FusionWiki - User contributions [en]

LNF: Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)

2026-04-08T11:37:22Z

Belenlmiranda:

== LNF - Nationally funded project ==

'''Title''': '''Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)'''

'''Reference''': PID2024-162966OA-I00

'''Programme and date''': Proyectos de Generación de Conocimiento 2024

'''Programme type (Modalidad de proyecto)''': Proyectos Generación de Conocimiento - Investigación orientada

'''Area/subarea (Área temática / subárea)''': Clima, Energía y Movilidad / Energía

'''Principal Investigator(s)''': Nerea Panadero [https://orcid.org/0000-0003-0462-2432] Belén López-Miranda [https://orcid.org/0000-0003-4236-7727]

'''Project type''': Proyecto individual

'''Start-end dates''': 01/09/2025 - 31/08/2029

'''Financing granted (direct costs)''': 218 750 €

'''Acknowledgement''': Grant PID2024-162966OA-I00 funded by MICIU/AEI/ 10.13039/501100011033 and by “ERDF/EU”.

[[File:LogoOficial_PlanNacional_2021.png|500px]]

== Description of the project ==
The PaRaPel project should be framed as a contributor to the solution of energy and climate problems. First, fusion has the potential to be a clean and sustainable energy source. Unlike fossil fuels, which release greenhouse gases, fusion reactor will produce no emissions. This could contribute to mitigating the effects of climate change. Second, it could be a reliable, abundant, and steady source of energy. This could make it a more robust energy source for population growing needs. Third, fusion power could help alleviating our dependence on foreign oil. Currently, we import about a large percentage of the used oil, making us vulnerable to price shocks and political instability. Fusion energy could contribute to reducing our dependence on foreign oil, making us more energy self-sufficient. Finally, fusion power could create new jobs and industries. The development of a fusion industry would create millions of new jobs and generate billions of euros in economic activity. There are, however, many challenges that need to be overcome before fusion power can become a reality. Indeed, MCF is a promising technology that could provide a clean and sustainable source of energy. Stellarators are one type of magnetic confinement device that has several advantages over tokamaks, such as intrinsic stability and operation in continuous mode. One of the key challenges is plasma fuelling. Understanding all the mechanisms that affect fuelling efficiency will enable the design of optimized fuelling schemes that result in peak density profiles, allowing stellarators to improve their performance and thus contribute to solving climate and energy-related problems. In particular, we expect to answer the following questions:

- How can fast particles affect the pellet ablation and the particle deposition in stellarators?

- How can fast ion losses affect the pellet fuelling and vice versa in stellarators?

- How can these results be extrapolated to reactor scenarios in order to improve the fuelling?

Characterizing and understanding the interaction of pellets and energetic particles could provide valuable insights into a critical area, helping to improve the design and operation of future fusion reactors. If we successfully meet this quest, it could contribute to lead to a new era of clean and abundant energy that could solve many of the world's most pressing problems.



== Project documentation ==

== Main results ==

During the 2025 financial year, the activities were carried out as part of project PID2024-162966OA-I00 (PaRaPel), with a view to achieving the objectives set out in "Plan Generación de Conocimiento 2024". These actions have contributed to the progress of the planned lines of work through the completion of technical tasks, inter-institutional coordination, and the development of interim results that strengthen the project’s implementation and ensure its continuity in subsequent phases. It is also worth highlighting the project’s marked cross-cutting nature, which has facilitated the coordination of activities that go beyond the initially defined objectives, integrating multidisciplinary approaches and fostering synergies between different fields of knowledge. This cross-cutting dimension has made it possible not only to optimise the use of interim results, but also to generate new complementary lines of work, reinforcing the project’s scientific and technical impact and its capacity to adapt to emerging challenges within the framework of the Plan. Consequently, the project’s development is not limited to the achievement of the specific objectives set out, but contributes more broadly to the advancement of knowledge and the consolidation of scientific collaboration networks of high strategic value.

== Dissemination of project results (peer-reviewed publications and conference presentations) ==

*Peer-reviewed publications:

1. P. Aguayo, G. Farias, A. González-Ganzábal, E. Fabregas, T. Estrada, B.van Milligen, A. Baciero, B. López-Miranda, F. Medina y G.A. Rattá-Gutiérrez, A data-driven approach to estimate plasma density in TJ-II stellarator. Fusion Engineering and Design 224 (2026) 115596.

2. A. González-Ganzábal, G.A. Rattá, T. Estrada, J. Martínez-Fernández, N. Panadero, Á. Cappa, B. López-Miranda,, A. Baciero, F. Martín, D. Tafalla, B.P. Van Milligen, F. Medina, Á. de la Peña, S. Dormido-Canto b , the TJ-II team. A comprehensive database of TJ-II signals and diagnostics for statistically based models. Fusion Engineering and Design 224 (2026) 115613

3. B. López-Miranda, D. Amador, J. Vega, S. Dormido-Canto, J. M. García-Regaña, J. de la Riva, A. Baciero, K. J. McCarthy, I. Pastor, and the TJ-II team. Estimation of ion temperature using an upgraded multichannel Doppler spectroscopic system in NBI-heated plasmas. Submitted manuscript (2026)

*Conference presentations:
1. N. Panadero. Fuelling a fusion reactor: a comparison of stellarators and tokamaks. Invited talk, 25th International Stellarator Heliotron Workshop (ISHW-2026), Córdoba,(Spain). 20th-24th April, 2026 https://ishw2026.com/invited-speakers/

2. B. López-Miranda, M. Delgado-Pérez, J. Vega, S. Dormido-Canto, D. Jiménez-Rey, N. Panadero, A. Baciero, I Pastor, and the TJ II team. Relative estimation of fast-ion losses in the TJ-II stellarator under different NBI-heating scenarios. P1.04, 25th International Stellarator Heliotron Workshop (ISHW-2026), Córdoba,(Spain). 20th-24th April, 2026 https://ishw2026.com/list-of-posters-contributions/

3. A. González-Ganzábal , G.A. Rattá , T. Estrada, J. Martínez Fernández, N. Panadero, Á.Cappa, B. López Miranda, A. Baciero , F. Martín, D. Tafalla, B.P. Van Milligen , F. Medina, Á. de la Peña,S. Dormido Canto, and the TJ II team. Development of a standardised TJ-II database for Machine Learning models and applications. P2.31, 25th International Stellarator Heliotron Workshop (ISHW-2026), Córdoba,(Spain). 20th-24th April, 2026 https://ishw2026.com/list-of-posters-contributions/

== References ==


<hr>
[[LNF:Nationally Funded Projects|Back to list of nationally funded projects]]

[[Category:LNF Nationally Funded Projects]]

LNF: Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)

2026-04-07T12:27:49Z

Belenlmiranda:

== LNF - Nationally funded project ==

'''Title''': '''Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)'''

'''Reference''': PID2024-162966OA-I00

'''Programme and date''': Proyectos de Generación de Conocimiento 2024

'''Programme type (Modalidad de proyecto)''': Proyectos Generación de Conocimiento - Investigación orientada

'''Area/subarea (Área temática / subárea)''': Clima, Energía y Movilidad / Energía

'''Principal Investigator(s)''': Nerea Panadero [https://orcid.org/0000-0003-0462-2432] Belén López-Miranda [https://orcid.org/0000-0003-4236-7727]

'''Project type''': Proyecto individual

'''Start-end dates''': 01/09/2025 - 31/08/2029

'''Financing granted (direct costs)''': 218 750 €

'''Acknowledgement''': Grant PID2024-162966OA-I00 funded by MICIU/AEI/ 10.13039/501100011033 and by “ERDF/EU”.

[[File:LogoOficial_PlanNacional_2021.png|500px]]

== Description of the project ==
The PaRaPel project should be framed as a contributor to the solution of energy and climate problems. First, fusion has the potential to be a clean and sustainable energy source. Unlike fossil fuels, which release greenhouse gases, fusion reactor will produce no emissions. This could contribute to mitigating the effects of climate change. Second, it could be a reliable, abundant, and steady source of energy. This could make it a more robust energy source for population growing needs. Third, fusion power could help alleviating our dependence on foreign oil. Currently, we import about a large percentage of the used oil, making us vulnerable to price shocks and political instability. Fusion energy could contribute to reducing our dependence on foreign oil, making us more energy self-sufficient. Finally, fusion power could create new jobs and industries. The development of a fusion industry would create millions of new jobs and generate billions of euros in economic activity. There are, however, many challenges that need to be overcome before fusion power can become a reality. Indeed, MCF is a promising technology that could provide a clean and sustainable source of energy. Stellarators are one type of magnetic confinement device that has several advantages over tokamaks, such as intrinsic stability and operation in continuous mode. One of the key challenges is plasma fuelling. Understanding all the mechanisms that affect fuelling efficiency will enable the design of optimized fuelling schemes that result in peak density profiles, allowing stellarators to improve their performance and thus contribute to solving climate and energy-related problems. In particular, we expect to answer the following questions:

- How can fast particles affect the pellet ablation and the particle deposition in stellarators?

- How can fast ion losses affect the pellet fuelling and vice versa in stellarators?

- How can these results be extrapolated to reactor scenarios in order to improve the fuelling?

Characterizing and understanding the interaction of pellets and energetic particles could provide valuable insights into a critical area, helping to improve the design and operation of future fusion reactors. If we successfully meet this quest, it could contribute to lead to a new era of clean and abundant energy that could solve many of the world's most pressing problems.



== Project documentation ==

== Main results ==

During the 2025 financial year, the activities were carried out as part of project PID2024-162966OA-I00 (PaRaPel), with a view to achieving the objectives set out in "Plan Generación de Conocimiento 2024". These actions have contributed to the progress of the planned lines of work through the completion of technical tasks, inter-institutional coordination, and the development of interim results that strengthen the project’s implementation and ensure its continuity in subsequent phases. It is also worth highlighting the project’s marked cross-cutting nature, which has facilitated the coordination of activities that go beyond the initially defined objectives, integrating multidisciplinary approaches and fostering synergies between different fields of knowledge. This cross-cutting dimension has made it possible not only to optimise the use of interim results, but also to generate new complementary lines of work, reinforcing the project’s scientific and technical impact and its capacity to adapt to emerging challenges within the framework of the Plan. Consequently, the project’s development is not limited to the achievement of the specific objectives set out, but contributes more broadly to the advancement of knowledge and the consolidation of scientific collaboration networks of high strategic value.

== Dissemination of project results (peer-reviewed publications and conference presentations) ==

*Peer-reviewed publications:

1. P. Aguayo, G. Farias, A. González-Ganzábal, E. Fabregas, T. Estrada, B.van Milligen, A. Baciero, B. López-Miranda, F. Medina y G.A. Rattá-Gutiérrez, A data-driven approach to estimate plasma density in TJ-II stellarator. Fusion Engineering and Design 224 (2026) 115596.

2. A. González-Ganzábal, G.A. Rattá, T. Estrada, J. Martínez-Fernández, N. Panadero, Á. Cappa, B. López-Miranda,, A. Baciero, F. Martín, D. Tafalla, B.P. Van Milligen, F. Medina, Á. de la Peña, S. Dormido-Canto b , the TJ-II team. A comprehensive database of TJ-II signals and diagnostics for statistically based models. Fusion Engineering and Design 224 (2026) 115613

3. B. López-Miranda, D. Amador, J. Vega, S. Dormido-Canto, J. M. García-Regaña, J. de la Riva, A. Baciero, K. J. McCarthy, I. Pastor, and the TJ-II team. Estimation of ion temperature using an upgraded multichannel Doppler spectroscopic system in NBI-heated plasmas. Submitted manuscript (2026)

*Conference presentations:
1. N. Panadero. Fuelling a fusion reactor: a comparison of stellarators and tokamaks. Invited talk, 25th International Stellarator Heliotron Workshop (ISHW-2026), Córdoba,(Spain). 20th-24th April, 2026 https://ishw2026.com/invited-speakers/

2. B. López-Miranda, M. Delgado-Pérez, J. Vega, S. Dormido-Canto, N. Panadero, A. Baciero, I Pastor, and the TJ II team. Relative estimation of fast-ion losses in the TJ-II stellarator under different NBI-heating scenarios. P1.04, 25th International Stellarator Heliotron Workshop (ISHW-2026), Córdoba,(Spain). 20th-24th April, 2026 https://ishw2026.com/list-of-posters-contributions/

3. A. González-Ganzábal , G.A. Rattá , T. Estrada, J. Martínez Fernández, N. Panadero, Á.Cappa, B. López Miranda, A. Baciero , F. Martín, D. Tafalla, B.P. Van Milligen , F. Medina, Á. de la Peña,S. Dormido Canto, and the TJ II team. Development of a standardised TJ-II database for Machine Learning models and applications. P2.31, 25th International Stellarator Heliotron Workshop (ISHW-2026), Córdoba,(Spain). 20th-24th April, 2026 https://ishw2026.com/list-of-posters-contributions/

== References ==


<hr>
[[LNF:Nationally Funded Projects|Back to list of nationally funded projects]]

[[Category:LNF Nationally Funded Projects]]

LNF: Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)

2026-03-26T09:51:13Z

Belenlmiranda:

== Dissemination of project results (peer-reviewed publications and conference presentations) ==

*Peer-reviewed publications:

1. P. Aguayo, G. Farias, A. González-Ganzábal, E. Fabregas, T. Estrada, B.van Milligen, A. Baciero, B. López-Miranda, F. Medina y G.A. Rattá-Gutiérrez, A data-driven approach to estimate plasma density in TJ-II stellarator. Fusion Engineering and Design 224 (2026) 115596.

2. A. González-Ganzábal, G.A. Rattá, T. Estrada, J. Martínez-Fernández, N. Panadero, Á. Cappa, B. López-Miranda,, A. Baciero, F. Martín, D. Tafalla, B.P. Van Milligen, F. Medina, Á. de la Peña, S. Dormido-Canto b , the TJ-II team. A comprehensive database of TJ-II signals and diagnostics for statistically based models. Fusion Engineering and Design 224 (2026) 115613

3. B. López-Miranda, D. Amador, J. Vega, S. Dormido-Canto, J. M. García-Regaña, J. de la Riva, A. Baciero, K. J. McCarthy, I. Pastor, and the TJ-II team. Estimation of ion temperature using an upgraded multichannel Doppler spectroscopic system in NBI-heated plasmas. Submitted manuscript (2026)

*Conference presentations:
1. N. Panadero. Fuelling a fusion reactor: a comparison of stellarators and tokamaks. Invited talk, 25th International Stellarator Heliotron Workshop (ISHW-2026), Córdoba,(Spain). 20th-24th April, 2026 https://ishw2026.com/invited-speakers/

2. B. López-Miranda, M. Delgado-Pérez, J. Vega, S. Dormido-Canto, N. Panadero, A. Baciero, I Pastor, and the TJ II team. Relative estimation of fast-ion losses in the TJ-II stellarator under different NBI-heating scenarios. P1.04, 25th International Stellarator Heliotron Workshop (ISHW-2026), Córdoba,(Spain). 20th-24th April, 2026 https://ishw2026.com/list-of-posters-contributions/

3. A. González-Ganzábal , G.A. Rattá , T. Estrada, J. Martínez Fernández, N. Panadero, Á.Cappa, B. López Miranda, A. Baciero , F. Martín, D. Tafalla, B.P. Van Milligen , F. Medina, Á. de la Peña,S. Dormido Canto, and the TJ II team. Development of a standardised TJ-II database for Machine Learning models and applications. P2.31, 25th International Stellarator Heliotron Workshop (ISHW-2026), Córdoba,(Spain). 20th-24th April, 2026 https://ishw2026.com/list-of-posters-contributions/

LNF: Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)

2026-03-19T08:25:58Z

Belenlmiranda: /* Dissemination of project results (peer-reviewed publications and conference presentations) */

== LNF - Nationally funded project ==

'''Title''': '''Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)'''

'''Reference''': PID2024-162966OA-I00

'''Programme and date''': Proyectos de Generación de Conocimiento 2024

'''Programme type (Modalidad de proyecto)''': Proyectos Generación de Conocimiento - Investigación orientada

'''Area/subarea (Área temática / subárea)''': Clima, Energía y Movilidad / Energía

'''Principal Investigator(s)''': Nerea Panadero [https://orcid.org/0000-0003-0462-2432] Belén López-Miranda [https://orcid.org/0000-0003-4236-7727]

'''Project type''': Proyecto individual

'''Start-end dates''': 01/09/2025 - 31/08/2029

'''Financing granted (direct costs)''': 218 750 €

'''Acknowledgement''': Grant PID2024-162966OA-I00 funded by MICIU/AEI/ 10.13039/501100011033 and by “ERDF/EU”.

[[File:LogoOficial_PlanNacional_2021.png|500px]]

== Description of the project ==
The PaRaPel project should be framed as a contributor to the solution of energy and climate problems. First, fusion has the potential to be a clean and sustainable energy source. Unlike fossil fuels, which release greenhouse gases, fusion reactor will produce no emissions. This could contribute to mitigating the effects of climate change. Second, it could be a reliable, abundant, and steady source of energy. This could make it a more robust energy source for population growing needs. Third, fusion power could help alleviating our dependence on foreign oil. Currently, we import about a large percentage of the used oil, making us vulnerable to price shocks and political instability. Fusion energy could contribute to reducing our dependence on foreign oil, making us more energy self-sufficient. Finally, fusion power could create new jobs and industries. The development of a fusion industry would create millions of new jobs and generate billions of euros in economic activity. There are, however, many challenges that need to be overcome before fusion power can become a reality. Indeed, MCF is a promising technology that could provide a clean and sustainable source of energy. Stellarators are one type of magnetic confinement device that has several advantages over tokamaks, such as intrinsic stability and operation in continuous mode. One of the key challenges is plasma fuelling. Understanding all the mechanisms that affect fuelling efficiency will enable the design of optimized fuelling schemes that result in peak density profiles, allowing stellarators to improve their performance and thus contribute to solving climate and energy-related problems. In particular, we expect to answer the following questions:

- How can fast particles affect the pellet ablation and the particle deposition in stellarators?

- How can fast ion losses affect the pellet fuelling and vice versa in stellarators?

- How can these results be extrapolated to reactor scenarios in order to improve the fuelling?

Characterizing and understanding the interaction of pellets and energetic particles could provide valuable insights into a critical area, helping to improve the design and operation of future fusion reactors. If we successfully meet this quest, it could contribute to lead to a new era of clean and abundant energy that could solve many of the world's most pressing problems.



== Project documentation ==

== Main results ==

During the 2025 financial year, the activities were carried out as part of project PID2024-162966OA-I00 (PaRaPel), with a view to achieving the objectives set out in "Plan Generación de Conocimiento 2024". These actions have contributed to the progress of the planned lines of work through the completion of technical tasks, inter-institutional coordination, and the development of interim results that strengthen the project’s implementation and ensure its continuity in subsequent phases. It is also worth highlighting the project’s marked cross-cutting nature, which has facilitated the coordination of activities that go beyond the initially defined objectives, integrating multidisciplinary approaches and fostering synergies between different fields of knowledge. This cross-cutting dimension has made it possible not only to optimise the use of interim results, but also to generate new complementary lines of work, reinforcing the project’s scientific and technical impact and its capacity to adapt to emerging challenges within the framework of the Plan. Consequently, the project’s development is not limited to the achievement of the specific objectives set out, but contributes more broadly to the advancement of knowledge and the consolidation of scientific collaboration networks of high strategic value.

== Dissemination of project results (peer-reviewed publications and conference presentations) ==

*Peer-reviewed publications:

1. P. Aguayo, G. Farias, A. González-Ganzábal, E. Fabregas, T. Estrada, B.van Milligen, A. Baciero, B. López-Miranda, F. Medina y G.A. Rattá-Gutiérrez, A data-driven approach to estimate plasma density in TJ-II stellarator. Fusion Engineering and Design 224 (2026) 115596.

2. A. González-Ganzábal, G.A. Rattá, T. Estrada, J. Martínez-Fernández, N. Panadero, Á. Cappa, B. López-Miranda,, A. Baciero, F. Martín, D. Tafalla, B.P. Van Milligen, F. Medina, Á. de la Peña, S. Dormido-Canto b , the TJ-II team. A comprehensive database of TJ-II signals and diagnostics for statistically based models. Fusion Engineering and Design 224 (2026) 115613

3. B. López-Miranda, D. Amador, J. Vega, S. Dormido-Canto, J. M. García-Regaña, J. de la Riva, A. Baciero, K. J. McCarthy, I. Pastor, and the TJ-II team. Estimation of ion temperature using an upgraded multichannel Doppler spectroscopic system in NBI-heated plasmas. Submitted manuscript (2026)

*Conference presentations:

== References ==


<hr>
[[LNF:Nationally Funded Projects|Back to list of nationally funded projects]]

[[Category:LNF Nationally Funded Projects]]

LNF: Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)

2026-03-19T07:30:14Z

Belenlmiranda: /* Dissemination of project results (peer-reviewed publications and conference presentations) */

== LNF - Nationally funded project ==

'''Title''': '''Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)'''

'''Reference''': PID2024-162966OA-I00

'''Programme and date''': Proyectos de Generación de Conocimiento 2024

'''Programme type (Modalidad de proyecto)''': Proyectos Generación de Conocimiento - Investigación orientada

'''Area/subarea (Área temática / subárea)''': Clima, Energía y Movilidad / Energía

'''Principal Investigator(s)''': Nerea Panadero [https://orcid.org/0000-0003-0462-2432] Belén López-Miranda [https://orcid.org/0000-0003-4236-7727]

'''Project type''': Proyecto individual

'''Start-end dates''': 01/09/2025 - 31/08/2029

'''Financing granted (direct costs)''': 218 750 €

'''Acknowledgement''': Grant PID2024-162966OA-I00 funded by MICIU/AEI/ 10.13039/501100011033 and by “ERDF/EU”.

[[File:LogoOficial_PlanNacional_2021.png|500px]]

== Description of the project ==
The PaRaPel project should be framed as a contributor to the solution of energy and climate problems. First, fusion has the potential to be a clean and sustainable energy source. Unlike fossil fuels, which release greenhouse gases, fusion reactor will produce no emissions. This could contribute to mitigating the effects of climate change. Second, it could be a reliable, abundant, and steady source of energy. This could make it a more robust energy source for population growing needs. Third, fusion power could help alleviating our dependence on foreign oil. Currently, we import about a large percentage of the used oil, making us vulnerable to price shocks and political instability. Fusion energy could contribute to reducing our dependence on foreign oil, making us more energy self-sufficient. Finally, fusion power could create new jobs and industries. The development of a fusion industry would create millions of new jobs and generate billions of euros in economic activity. There are, however, many challenges that need to be overcome before fusion power can become a reality. Indeed, MCF is a promising technology that could provide a clean and sustainable source of energy. Stellarators are one type of magnetic confinement device that has several advantages over tokamaks, such as intrinsic stability and operation in continuous mode. One of the key challenges is plasma fuelling. Understanding all the mechanisms that affect fuelling efficiency will enable the design of optimized fuelling schemes that result in peak density profiles, allowing stellarators to improve their performance and thus contribute to solving climate and energy-related problems. In particular, we expect to answer the following questions:

- How can fast particles affect the pellet ablation and the particle deposition in stellarators?

- How can fast ion losses affect the pellet fuelling and vice versa in stellarators?

- How can these results be extrapolated to reactor scenarios in order to improve the fuelling?

Characterizing and understanding the interaction of pellets and energetic particles could provide valuable insights into a critical area, helping to improve the design and operation of future fusion reactors. If we successfully meet this quest, it could contribute to lead to a new era of clean and abundant energy that could solve many of the world's most pressing problems.



== Project documentation ==

== Main results ==

During the 2025 financial year, the activities were carried out as part of project PID2024-162966OA-I00 (PaRaPel), with a view to achieving the objectives set out in "Plan Generación de Conocimiento 2024". These actions have contributed to the progress of the planned lines of work through the completion of technical tasks, inter-institutional coordination, and the development of interim results that strengthen the project’s implementation and ensure its continuity in subsequent phases. It is also worth highlighting the project’s marked cross-cutting nature, which has facilitated the coordination of activities that go beyond the initially defined objectives, integrating multidisciplinary approaches and fostering synergies between different fields of knowledge. This cross-cutting dimension has made it possible not only to optimise the use of interim results, but also to generate new complementary lines of work, reinforcing the project’s scientific and technical impact and its capacity to adapt to emerging challenges within the framework of the Plan. Consequently, the project’s development is not limited to the achievement of the specific objectives set out, but contributes more broadly to the advancement of knowledge and the consolidation of scientific collaboration networks of high strategic value.

== Dissemination of project results (peer-reviewed publications and conference presentations) ==

Peer-reviewed publications:

1. P. Aguayo, G. Farias, A. González-Ganzábal, E. Fabregas, T. Estrada, B.van Milligen, A. Baciero, B. López-Miranda, F. Medina y G.A. Rattá-Gutiérrez, A data-driven approach to estimate plasma density in TJ-II stellarator. Fusion Engineering and Design 224 (2026) 115596.

2. A. González-Ganzábal, G.A. Rattá, T. Estrada, J. Martínez-Fernández, N. Panadero, Á. Cappa, B. López-Miranda,, A. Baciero, F. Martín, D. Tafalla, B.P. Van Milligen, F. Medina, Á. de la Peña, S. Dormido-Canto b , the TJ-II team. A comprehensive database of TJ-II signals and diagnostics for statistically based models. Fusion Engineering and Design 224 (2026) 115613

3. B. López-Miranda, D. Amador, J. Vega, S. Dormido-Canto, J. M. García-Regaña, J. de la Riva, A. Baciero, K. J. McCarthy, I. Pastor, and the TJ-II team. Estimation of ion temperature using an upgraded multichannel Doppler spectroscopic system in NBI-heated plasmas. Submitted manuscript (2026)

== References ==


<hr>
[[LNF:Nationally Funded Projects|Back to list of nationally funded projects]]

[[Category:LNF Nationally Funded Projects]]

LNF: Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)

2026-03-19T07:27:08Z

Belenlmiranda: /* Dissemination of project results (peer-reviewed publications and conference presentations) */

== LNF - Nationally funded project ==

'''Title''': '''Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)'''

'''Reference''': PID2024-162966OA-I00

'''Programme and date''': Proyectos de Generación de Conocimiento 2024

'''Programme type (Modalidad de proyecto)''': Proyectos Generación de Conocimiento - Investigación orientada

'''Area/subarea (Área temática / subárea)''': Clima, Energía y Movilidad / Energía

'''Principal Investigator(s)''': Nerea Panadero [https://orcid.org/0000-0003-0462-2432] Belén López-Miranda [https://orcid.org/0000-0003-4236-7727]

'''Project type''': Proyecto individual

'''Start-end dates''': 01/09/2025 - 31/08/2029

'''Financing granted (direct costs)''': 218 750 €

'''Acknowledgement''': Grant PID2024-162966OA-I00 funded by MICIU/AEI/ 10.13039/501100011033 and by “ERDF/EU”.

[[File:LogoOficial_PlanNacional_2021.png|500px]]

== Description of the project ==
The PaRaPel project should be framed as a contributor to the solution of energy and climate problems. First, fusion has the potential to be a clean and sustainable energy source. Unlike fossil fuels, which release greenhouse gases, fusion reactor will produce no emissions. This could contribute to mitigating the effects of climate change. Second, it could be a reliable, abundant, and steady source of energy. This could make it a more robust energy source for population growing needs. Third, fusion power could help alleviating our dependence on foreign oil. Currently, we import about a large percentage of the used oil, making us vulnerable to price shocks and political instability. Fusion energy could contribute to reducing our dependence on foreign oil, making us more energy self-sufficient. Finally, fusion power could create new jobs and industries. The development of a fusion industry would create millions of new jobs and generate billions of euros in economic activity. There are, however, many challenges that need to be overcome before fusion power can become a reality. Indeed, MCF is a promising technology that could provide a clean and sustainable source of energy. Stellarators are one type of magnetic confinement device that has several advantages over tokamaks, such as intrinsic stability and operation in continuous mode. One of the key challenges is plasma fuelling. Understanding all the mechanisms that affect fuelling efficiency will enable the design of optimized fuelling schemes that result in peak density profiles, allowing stellarators to improve their performance and thus contribute to solving climate and energy-related problems. In particular, we expect to answer the following questions:

- How can fast particles affect the pellet ablation and the particle deposition in stellarators?

- How can fast ion losses affect the pellet fuelling and vice versa in stellarators?

- How can these results be extrapolated to reactor scenarios in order to improve the fuelling?

Characterizing and understanding the interaction of pellets and energetic particles could provide valuable insights into a critical area, helping to improve the design and operation of future fusion reactors. If we successfully meet this quest, it could contribute to lead to a new era of clean and abundant energy that could solve many of the world's most pressing problems.



== Project documentation ==

== Main results ==

During the 2025 financial year, the activities were carried out as part of project PID2024-162966OA-I00 (PaRaPel), with a view to achieving the objectives set out in "Plan Generación de Conocimiento 2024". These actions have contributed to the progress of the planned lines of work through the completion of technical tasks, inter-institutional coordination, and the development of interim results that strengthen the project’s implementation and ensure its continuity in subsequent phases. It is also worth highlighting the project’s marked cross-cutting nature, which has facilitated the coordination of activities that go beyond the initially defined objectives, integrating multidisciplinary approaches and fostering synergies between different fields of knowledge. This cross-cutting dimension has made it possible not only to optimise the use of interim results, but also to generate new complementary lines of work, reinforcing the project’s scientific and technical impact and its capacity to adapt to emerging challenges within the framework of the Plan. Consequently, the project’s development is not limited to the achievement of the specific objectives set out, but contributes more broadly to the advancement of knowledge and the consolidation of scientific collaboration networks of high strategic value.

== Dissemination of project results (peer-reviewed publications and conference presentations) ==

1. P. Aguayo, G. Farias, A. González-Ganzábal, E. Fabregas, T. Estrada, B.van Milligen, A. Baciero, B. López-Miranda, F. Medina y G.A. Rattá-Gutiérrez, A data-driven approach to estimate plasma density in TJ-II stellarator. Fusion Engineering and Design 224 (2026) 115596.

2. A. González-Ganzábal, G.A. Rattá, T. Estrada, J. Martínez-Fernández, N. Panadero, Á. Cappa, B. López-Miranda,, A. Baciero, F. Martín, D. Tafalla, B.P. Van Milligen, F. Medina, Á. de la Peña, S. Dormido-Canto b , the TJ-II team. A comprehensive database of TJ-II signals and diagnostics for statistically based models. Fusion Engineering and Design 224 (2026) 115613

3. B. López-Miranda, D. Amador, J. Vega, S. Dormido-Canto, J. M. García-Regaña, J. de la Riva, A. Baciero, K. J. McCarthy, I. Pastor, and the TJ-II team. Estimation of ion temperature using an upgraded multichannel Doppler spectroscopic system in NBI-heated plasmas. Submitted manuscript (2026)

== References ==


<hr>
[[LNF:Nationally Funded Projects|Back to list of nationally funded projects]]

[[Category:LNF Nationally Funded Projects]]

LNF: Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)

2026-03-19T07:23:13Z

Belenlmiranda: /* Main results */

== LNF - Nationally funded project ==

'''Title''': '''Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)'''

'''Reference''': PID2024-162966OA-I00

'''Programme and date''': Proyectos de Generación de Conocimiento 2024

'''Programme type (Modalidad de proyecto)''': Proyectos Generación de Conocimiento - Investigación orientada

'''Area/subarea (Área temática / subárea)''': Clima, Energía y Movilidad / Energía

'''Principal Investigator(s)''': Nerea Panadero [https://orcid.org/0000-0003-0462-2432] Belén López-Miranda [https://orcid.org/0000-0003-4236-7727]

'''Project type''': Proyecto individual

'''Start-end dates''': 01/09/2025 - 31/08/2029

'''Financing granted (direct costs)''': 218 750 €

'''Acknowledgement''': Grant PID2024-162966OA-I00 funded by MICIU/AEI/ 10.13039/501100011033 and by “ERDF/EU”.

[[File:LogoOficial_PlanNacional_2021.png|500px]]

== Description of the project ==
The PaRaPel project should be framed as a contributor to the solution of energy and climate problems. First, fusion has the potential to be a clean and sustainable energy source. Unlike fossil fuels, which release greenhouse gases, fusion reactor will produce no emissions. This could contribute to mitigating the effects of climate change. Second, it could be a reliable, abundant, and steady source of energy. This could make it a more robust energy source for population growing needs. Third, fusion power could help alleviating our dependence on foreign oil. Currently, we import about a large percentage of the used oil, making us vulnerable to price shocks and political instability. Fusion energy could contribute to reducing our dependence on foreign oil, making us more energy self-sufficient. Finally, fusion power could create new jobs and industries. The development of a fusion industry would create millions of new jobs and generate billions of euros in economic activity. There are, however, many challenges that need to be overcome before fusion power can become a reality. Indeed, MCF is a promising technology that could provide a clean and sustainable source of energy. Stellarators are one type of magnetic confinement device that has several advantages over tokamaks, such as intrinsic stability and operation in continuous mode. One of the key challenges is plasma fuelling. Understanding all the mechanisms that affect fuelling efficiency will enable the design of optimized fuelling schemes that result in peak density profiles, allowing stellarators to improve their performance and thus contribute to solving climate and energy-related problems. In particular, we expect to answer the following questions:

- How can fast particles affect the pellet ablation and the particle deposition in stellarators?

- How can fast ion losses affect the pellet fuelling and vice versa in stellarators?

- How can these results be extrapolated to reactor scenarios in order to improve the fuelling?

Characterizing and understanding the interaction of pellets and energetic particles could provide valuable insights into a critical area, helping to improve the design and operation of future fusion reactors. If we successfully meet this quest, it could contribute to lead to a new era of clean and abundant energy that could solve many of the world's most pressing problems.



== Project documentation ==

== Main results ==

During the 2025 financial year, the activities were carried out as part of project PID2024-162966OA-I00 (PaRaPel), with a view to achieving the objectives set out in "Plan Generación de Conocimiento 2024". These actions have contributed to the progress of the planned lines of work through the completion of technical tasks, inter-institutional coordination, and the development of interim results that strengthen the project’s implementation and ensure its continuity in subsequent phases. It is also worth highlighting the project’s marked cross-cutting nature, which has facilitated the coordination of activities that go beyond the initially defined objectives, integrating multidisciplinary approaches and fostering synergies between different fields of knowledge. This cross-cutting dimension has made it possible not only to optimise the use of interim results, but also to generate new complementary lines of work, reinforcing the project’s scientific and technical impact and its capacity to adapt to emerging challenges within the framework of the Plan. Consequently, the project’s development is not limited to the achievement of the specific objectives set out, but contributes more broadly to the advancement of knowledge and the consolidation of scientific collaboration networks of high strategic value.

== Dissemination of project results (peer-reviewed publications and conference presentations) ==

P. Aguayo, G. Farias, A. González-Ganzábal, E. Fabregas, T. Estrada, B.van Milligen, A. Baciero, B. López-Miranda, F. Medina y G.A. Rattá-Gutiérrez, A data-driven approach to estimate plasma density in TJ-II stellarator. Fusion Engineering and Design 224 (2026) 115596.

A. González-Ganzábal, G.A. Rattá, T. Estrada, J. Martínez-Fernández, N. Panadero, Á. Cappa, B. López-Miranda,, A. Baciero, F. Martín, D. Tafalla, B.P. Van Milligen, F. Medina, Á. de la Peña, S. Dormido-Canto b , the TJ-II team. A comprehensive database of TJ-II signals and diagnostics for statistically based models. Fusion Engineering and Design 224 (2026) 115613

B. López-Miranda, D. Amador, J. Vega, S. Dormido-Canto, J. M. García-Regaña, J. de la Riva, A. Baciero, K. J. McCarthy, I. Pastor, and the TJ-II team. Estimation of ion temperature using an upgraded multichannel Doppler spectroscopic system in NBI-heated plasmas. Submitted manuscript (2026)

== References ==


<hr>
[[LNF:Nationally Funded Projects|Back to list of nationally funded projects]]

[[Category:LNF Nationally Funded Projects]]

LNF: Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)

2026-03-19T07:20:18Z

Belenlmiranda: /* Project documentation */

LNF: Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)

2026-03-18T14:52:22Z

Belenlmiranda: Created page with "== LNF - Nationally funded project == '''Title''': '''Evaluation of the impact of fast particles on refuelling with cryogenic pellets in stellarator reactors (PaRaPel)''' '''Reference''': PID2024-162966OA-I00 '''Programme and date''': Proyectos de Generación de Conocimiento 2024 '''Programme type (Modalidad de proyecto)''': Proyectos Generación de Conocimiento - Investigación orientada '''Area/subarea (Área temática / subárea)''': Clima, Energía y Movilidad..."

TJ-II: Impurity injection by laser blow-off (LBO): Confinement and transport studies of high Z impurity injection by LBO in ion-root scenarios (II). Comparison to neoclassical and turbulence simulations.

2022-01-13T14:12:48Z

Belenlmiranda: Created page with "== Experimental campaign == Spring 2022 == Proposal title == '''TJ-II: Impurity injection by laser blow-off (LBO): Confinement and transport studies of high Z impurity inject..."

== Experimental campaign ==
Spring 2022

== Proposal title ==
'''TJ-II: Impurity injection by laser blow-off (LBO): Confinement and transport studies of high Z impurity injection by LBO in ion-root scenarios (II). Comparison to neoclassical and turbulence simulations.'''

== Name and affiliation of proponent ==
[https://orcid.org/0000-0003-4236-7727 López-Miranda, B.], [https://orcid.org/0000-0003-1717-3509 Baciero, A.], [https://orcid.org/0000-0001-7521-4503 Ochando, M. A.], Medina, F., [https://orcid.org/0000-0002-5881-1442 McCarthy K. J.], [https://orcid.org/0000-0001-7632-3357 García-Regaña, J. M.], [https://orcid.org/0000-0001-8510-1422 Velasco, J. L.], Melnikov, A., [https://orcid.org/0000-0003-0891-0941 Pastor, I.], HIBP group and the TJ-II team,
Laboratorio Nacional de Fusion, CIEMAT (Spain)

== Details of contact person at LNF ==
belen.lopez.miranda@ciemat.es

== Description of the activity ==
'''Motivation.'''

In previous works [1, 2, 3], we have studied impurity (BC, LiF, BN, Fe) transport mainly in ECRH plasmas heated by ECR [2]. Transport has been measured in low-density regimes (injecting controlled amounts of B or Fe impurities), where the radial electric field is positive, Er > 0, and the plasma is in the electron root. Several limitations were found to inject heavy impurities (Fe, W), particularly in high-density regimes, due to the intrinsic limitation of the cut-off density that interrupts the discharge and the lack of density control due to the absence of a true plateau. Near the value of the density where the transition to a positive electric field occurs (from electron-root to ion-root), an increase in confinement time was observed, but in those discharges with higher densities, the estimated confinement time was much longer than the duration of the discharge and it was not possible to deduce any value for the confinement time. Here we try to study the confinement time in ion-root regimes using LBO in order to investigate the behaviour of heavy impurities injected both in electron-root regimes and in ion-root regimes TJ-II plasmas. We also would compare the experimental results with the predictions of neoclassical transport in order to figure out the mechanisms involved in these processes.

'''Proposal.'''

We plan to inject heavy impurities (Fe, W) by means of LBO into TJ-II discharges. This scenario requires a constant high line averaged density (0.9×1019 m-3), similar to 48223. For this, the confinement times of the impurities and the transport coefficients will be estimated after injecting impurities of different masses. The confinement times of the impurities will be deduced from the decay of different radiation signals. Thanks to the reconstructions of bolometric and X-ray radiation profiles [4, 5], an attempt will be made to deduce the diffusion (D) and transport (v) coefficients that account for these emissions by using the STRAHL [6] transport code. Finally, since neoclassical transport simulations also predict differences in transport in different regimes [7], we would compare these results with the simulations of the EUTERPE [8] and STELLA codes used to estimate neoclassical and turbulence transport respectively.

'''Discharges and diagnostics.'''

We need discharges with good control of plasma density discharges in a fixed magnetic configuration (100_44_64). We wish plasma electron densities were sufficiently high to obtain good Thomson Scattering profiles before and after impurity injection. Main diagnostics, apart from standard monitors, will be radiation diagnostics (bolometers, X-ray detectors, VUV spectrometer, etc.), and we also need the values of Er with HIBP system and Doppler reflectometer. It is necessary to obtain the ion temperature profiles using the NPA system. A good plasma-wall condition is also required, so we prefer a fresh-lithiated wall.
The transport properties of a selected group of discharges will be analyzed with the transport code STRAHL. The values of D and v coefficients obtained by STRAHL will be compared with neoclassical simulations in DKES/EUTERPE and with the turbulence code STELLA or similar ones performed by the TJ-II theoretical group.

== International or National funding project or entity ==
This work was funded by the projects from the Spanish Ministerio de Ciencia e Innovación RTI2018-100835-B-I00 (MCIU/AEI/FEDER, UE) and PID2020-116599RB-I00.

== Description of required resources ==
Required resources:
* Number of plasma discharges or days of operation: 3 days

* Essential diagnostic systems: Nd:YAG laser, spectroscopic system, Bolometric arrays, X-Ray detectors, VUV spectrometer, Thomson Scattering, NPA system, Doppler reflectometer, HIBP.
* Type of plasmas (heating configuration): standard configuration (100_44_64), ECRH, and NBI, this scenario requires a constant high line averaged density (0.9×1019 m-3), similar to 48223.

* Specific requirements on wall conditioning if any: fresh-lithiated wall.

* External users: need a local computer account for data access: no

* Any external equipment to be integrated? Provide description and integration needs:

== Preferred dates and degree of flexibility ==
Preferred dates: (format dd-mm-yyyy)


== References ==
<references />
[1] Zurro B, Hollmann E, Baciero A, Ochando MA, Medina F, McCarthy KJ et al., (2011). Transport studies using laser blow-off injection of low-Z trace impurities injected into the TJ-II stellarator, Nuclear Fusion 51 (2011) 063015 (9pp).

[2] Zurro B., Hollmann, E. M., Baciero, A., Ochando, M. A., Medina, F. et al., (2014). Studying the impurity charge and main ion mass dependence of impurity confinement in ECR-heated TJ-II stellarator, Plasma Phys. Control. Fusion 56, [124007].

https://doi.org/10.1088/0741-3335/56/12/124007

[3] Zurro, B., Velasco, J. L., Hollmann, E. M., Baciero, A., et al, (2015). Transport analysis of impurities injected by laser blow-off in ECRH and NBI heated plasmas of TJ-II, Proc. EPS 2015. Lisbon.

[4] Medina, F., Pedrosa, M. A., Ochando, M. A., Rodríguez-Rodrigo, L., Hidalgo, C. et al., (2001). Filamentary current detection in stellarator plasmas. Rev. Sci. Instrum. 72, [471]. https://doi.org/10.1063/1.1310579

[5] Ochando, M. A., Medina, F., Zurro, B., Baciero, A., McCarthy, K. J. et al., (2006). Up-down and in-out asymmetry monitoring based on broadband radiation detectors. Fusion Sci. Tech. 50, [31]. https://doi.org/10.13182/FST06-A1252

[6] Dux, R., Neu, R., Peeters, A. G., Pereverzev, G., Mück, A. et al., (2003). Plasma Phys. Control. Fusion 45, [1815]. https,//doi.org/10.1088/0741-3335/45/9/317

[7] Velasco J. L., Calvo, I., Satake, S., Alonso, A., Nunami, M. et al., (2017). Moderation of neoclassical impurity accumulation in high-temperature plasmas of helical devices, Nucl. Fusion, 57, [016016]. https://doi.org/10.1088/0029-5515/57/1/016016

[8] García-Regaña, J. M., Beidler, C. D., Kleiber, R., Helander, P., Mollen, A. et al., (2017). Electrostatic potential variation on the flux surface and its impact on impurity transport. Nucl. Fusion 57, [056004]. https://doi.org/10.1088/1741-4326/aa5fd5

<hr>
[[TJ-II:Experimental proposals|Back to list of experimental proposals]]

[[Category:TJ-II internal documents]]
[[Category:TJ-II experimental proposals Spring 2022]]

TJ-II:Impurity transport studies by LILA-TOF detection. A Lithium Laser-Ablation based Time-of-Flight (LILA-TOF) diagnostic for measuring plasma edge ion temperature (II). Influence of toroidal plasma rotation

2022-01-13T13:37:16Z

Belenlmiranda: Created page with "== Experimental campaign == Spring 2022 == Proposal title == '''TJ-II:Impurity transport studies by LILA-TOF detection. A Lithium Laser-Ablation based Time-of-Flight (LILA-TO..."

== Experimental campaign ==
Spring 2022

== Proposal title ==
'''TJ-II:Impurity transport studies by LILA-TOF detection. A Lithium Laser-Ablation based Time-of-Flight (LILA-TOF) diagnostic for measuring plasma edge ion temperature (II). Influence of toroidal plasma rotation'''

== Name and affiliation of proponent ==

[https://orcid.org/0000-0003-4236-7727 López-Miranda, B.], Tabarés, F.,[https://orcid.org/0000-0003-1717-3509 Baciero, A.], [https://orcid.org/0000-0001-7521-4503 Ochando, M. A.], Medina, F.,Tafalla. D., [https://orcid.org/0000-0002-5881-1442 McCarthy K. J.], Laboratorio Nacional de Fusion, CIEMAT (Spain)

== Details of contact person at LNF ==

belen.lopez.miranda@ciemat.es

== Description of the activity ==
'''Background:'''

Although several methods for the measurement of Ti at the edge of TJ-II have been tried (RFA, He beam, Doppler spectroscopy…) [1-7] no systematic recording of this important parameter has been achieved so far. A new method for studying the thermalization and transport of injected impurities at the edge of hot plasma, (considering the last closed magnetic surface, the free path is between 1 to 2 cm approx.) under no perturbative conditions, was developed [8] using a Nd:YAG laser called Lithium Laser-Ablation based Time-of-Flight (LILA-TOF) technique. Ion temperatures deduced from the application of this technique (25 eV in the edge) are in good agreement with previous measurements in TJ-II by Retarding Field Analyzer (RFA) (17-21 eV in the SOL) [9].

'''Description:'''

In the proposed technique, a Nd:YAG laser is used to ablate Li from the lithiated wall of the stellarator TJ-II. While the laser pulse allows for the analysis of the released species through Laser-Induced Breakdown Spectroscopy (LIBS) [10], its laser pulse also provides a time reference for the Time-of-Flight (TOF) measurements of the Li+ ions performed. This is done by positioning light detection systems sensitive to an intense Li II spectral line at different toroidal locations away from such a source. TOF times of tens to hundreds of microseconds are recorded. Fast recording of the TOF of the Li+ emission toroidally away from the source will provide the energy distribution of the thermalized particles.
Then, by de-convolving the shape of the recorded light pulse, the velocity distribution of the lithium-ion during its thermalization with the background plasma can be extracted. From this velocity distribution, the ion temperature of the background ions and the toroidal rotation at the plasma periphery can be deduced. The viability of injecting Li using LIBS and recording the lithium traces of the plasma-generated Li+ ions to study ion toroidal, and, consequently, deducing the TOF using its propagation has been demonstrated [10]. The preliminary values of Ti and vrot deduced are consistent with those measured with other diagnostics in TJ-II. Several limitations have been identified as the influence of plasma toroidal rotation. This parameter has a direct impact on the shape of the TOF trace.

'''Proposal:'''

Consequently, this proposal is oriented to obtain a more accurate estimation of the rotation and Ti would be performed by simultaneously recording the lithium traces at two toroidal locations, on opposite sides of the injection point whenever available. Reproducible plasmas are required to compare the Ti obtained using TOF measurements in the different TJ-II monitors located in opposite sectors.

== International or National funding project or entity ==
This work was funded by the projects from the Spanish Ministerio de Ciencia e Innovación RTI2018-100835-B-I00 (MCIU/AEI/FEDER, UE) and PID2020-116599RB-I00.

== Description of required resources ==
'''Required resources:'''

 Number of plasma discharges or days of operation: 3 days

 Essential diagnostic systems: Nd:YAG laser, spectroscopic system, Bolometric arrays, X-Ray detectors, VUV spectrometer, Thomson Scattering, Doppler reflectometer.

 Type of plasmas (heating configuration): standard configuration (100_44_64), ECRH, this scenario requires a constant high line averaged density, similar to March 24th, 2021.

 Specific requirements on wall conditioning if any: fresh-lithiated wall.

 External users: need a local computer account for data access: no

 Any external equipment to be integrated? Provide description and integration needs:

== Preferred dates and degree of flexibility ==
Preferred dates: (format dd-mm-yyyy)


== References ==
<references />
[1] Kocan, K., Gunn, J. P., Komm, M., et al. 2008. Rev. Sci. Instr. 79 073502

[2] Katsumata, I. and Okazaki, M., 1967. Jpn. J. Appl. Phys 6 123

[3] Zurro, B., Vega, J., Castejón, F., et al. 1992. Phys Rev Lett. 69 2919

[4] McCarthy, K. J., Zurro, B., Balbín R., et al., 2003. Europhys. Lett., 63 (1), 49-55

[5] Pitcher, C. S. and Stangeby, P. C., 1981. Plasma Phys. Control. Fusion 31 1305

[6] Tabarés, F. L., Tafalla, D., Ferreira J. A., et al. 2010. Rev. Sci. Instr. 81 10D708

[7] Tabarés, F. L. and Tafalla, D., 2015. Nucl. Fus. 55 013020

[8] López-Miranda, B., Tabarés, F. L., McCarthy, K. J., Baciero, A., D. Tafalla, F. L., et al. 2021. Plasma Phys. Control. Fusion, submitted.

[9] Nedzelskiy I. S., Silva C., Fernández H., et al., 2009. Probl. Atom. Sci. Tech. 1, 174

[10] López-Miranda, B., Zurro, B., Baciero, et al., (2018). Investigation of the toroidal propagation of lithium injected by LIBS into TJ-II plasmas to measure edge ion temperature. EPS Conference Prague.
<hr>
[[TJ-II:Experimental proposals|Back to list of experimental proposals]]

[[Category:TJ-II internal documents]]
[[Category:TJ-II experimental proposals Spring 2022]]

TJ-II:Impurity transport studies by LILA-TOF detection. A Lithium Laser-Ablation based Time-of-Flight (LILA-TOF) diagnostic for measuring plasma edge ion temperature and toroidal plasma rotation

2022-01-13T13:29:39Z

Belenlmiranda: /* Name and affiliation of proponent */

== Experimental campaign ==
Autumn 2021

== Proposal title ==
'''Impurity transport studies by LILA-TOF detection: A Lithium Laser-Ablation based Time-of-Flight (LILA-TOF) diagnostic for measuring plasma edge ion temperature and toroidal plasma rotation'''

== Name and affiliation of proponent ==
López-Miranda, B., Tabarés, F., Baciero, A., Ochando, M. A., Medina, F., Tafalla. D., McCarthy, K. J.,
Laboratorio Nacional de Fusion, CIEMAT (Spain)

== Details of contact person at LNF ==
belen.lopez.miranda@ciemat.es
== Description of the activity ==
Background:

Although several methods for the measurement of Ti at the edge of TJ-II have been tried (RFA, He beam, Doppler spectroscopy…) [1-7] no systematic recording of this important parameter has been achieved so far. A new method for studying the thermalization and transport of injected impurities at the edge of hot plasma, (considering the last closed magnetic surface, the free path is between 1 to 2 cm approx.) under no perturbative conditions, was developed [8] using a Nd:YAG laser called Lithium Laser-Ablation based Time-of-Flight (LILA-TOF) technique. Ion temperatures deduced from the application of this technique (25 eV in the edge) are in good agreement with previous measurements in TJ-II by Retarding Field Analyzer (RFA) (17-21 eV in the SOL) [9].

Description:

In the proposed technique, a Nd:YAG laser is used to ablate Li from the lithiated wall of the stellarator TJ-II. While the laser pulse allows for the analysis of the released species through Laser-Induced Breakdown Spectroscopy (LIBS) [10], its laser pulse also provides a time reference for the Time-of-Flight (TOF) measurements of the Li+ ions performed. This is done by positioning light detection systems sensitive to an intense Li II spectral line at different toroidal locations away from such a source. TOF times of tens to hundreds of microseconds are recorded. Fast recording of the TOF of the Li+ emission toroidally away from the source will provide the energy distribution of the thermalized particles.
Then, by de-convolving the shape of the recorded light pulse, the velocity distribution of the lithium-ion during its thermalization with the background plasma can be extracted. From this velocity distribution, the ion temperature of the background ions and the toroidal rotation at the plasma periphery can be deduced. The viability of injecting Li using LIBS and recording the lithium traces of the plasma-generated Li+ ions to study ion toroidal, and, consequently, deducing the TOF using its propagation has been demonstrated [10]. The preliminary values of Ti and vrot deduced are consistent with those measured with other diagnostics in TJ-II. Several limitations have been identified as the influence of plasma toroidal rotation. This parameter has a direct impact on the shape of the TOF trace. Consequently, this proposal is oriented to obtain a more accurate estimation of the rotation and Ti would be performed by simultaneously recording the lithium traces at two toroidal locations, on opposite sides of the injection point whenever available. Reproducible plasmas are required to compare the Ti obtained using TOF measurements in the different TJ-II monitors located in opposite sectors.

== International or National funding project or entity ==
This work was funded by the projects from the Spanish Ministerio de Ciencia e Innovación RTI2018-100835-B-I00 (MCIU/AEI/FEDER, UE) and PID2020-116599RB-I00.
== Description of required resources ==
Required resources:

 Number of plasma discharges or days of operation: 3 days

 Essential diagnostic systems: Nd:YAG laser, spectroscopic system, Bolometric arrays, X-Ray detectors, VUV spectrometer, Thomson Scattering, Doppler reflectometer.

 Type of plasmas (heating configuration): standard configuration (100_44_64), ECRH, this scenario requires a constant high line averaged density, similar to March 24th, 2021.

 Specific requirements on wall conditioning if any: fresh-lithiated wall.

 External users: need a local computer account for data access: no

 Any external equipment to be integrated? Provide description and integration needs:

== Preferred dates and degree of flexibility ==
Preferred dates: (format dd-mm-yyyy)


== References ==
<references />
[1] Kocan, K., Gunn, J. P., Komm, M., et al. 2008. Rev. Sci. Instr. 79 073502

[2] Katsumata, I. and Okazaki, M., 1967. Jpn. J. Appl. Phys 6 123

[3] Zurro, B., Vega, J., Castejón, F., et al. 1992. Phys Rev Lett. 69 2919

[4] McCarthy, K. J., Zurro, B., Balbín R., et al., 2003. Europhys. Lett., 63 (1), 49-55

[5] Pitcher, C. S. and Stangeby, P. C., 1981. Plasma Phys. Control. Fusion 31 1305

[6] Tabarés, F. L., Tafalla, D., Ferreira J. A., et al. 2010. Rev. Sci. Instr. 81 10D708

[7] Tabarés, F. L. and Tafalla, D., 2015. Nucl. Fus. 55 013020

[8] López-Miranda, B., Tabarés, F. L., McCarthy, K. J., Baciero, A., D. Tafalla, F. L., et al. 2021. Plasma Phys. Control. Fusion, submitted.

[9] Nedzelskiy I. S., Silva C., Fernández H., et al., 2009. Probl. Atom. Sci. Tech. 1, 174

[10] López-Miranda, B., Zurro, B., Baciero, et al., (2018). Investigation of the toroidal propagation of lithium injected by LIBS into TJ-II plasmas to measure edge ion temperature. EPS Conference Prague.

<hr>
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[[Category:TJ-II internal documents]]
[[Category:TJ-II experimental proposals Autumn 2021]]

TJ-II: Zeff measurement using visible bremsstrahlung (VB) with NBI heating (II)

2022-01-13T13:24:08Z

Belenlmiranda: Created page with "== Experimental campaign == Spring 2022 == Proposal title == '''Zeff measurement using visible bremsstrahlung (VB) with NBI heating (II) ''' == Name and affiliation of prop..."

== Experimental campaign ==
Spring 2022

== Proposal title ==
'''Zeff measurement using visible bremsstrahlung (VB) with NBI heating (II)

'''

== Name and affiliation of proponent ==

[https://orcid.org/0000-0003-4236-7727 López-Miranda, B.], [https://orcid.org/0000-0003-1717-3509 Baciero, A.], [https://orcid.org/0000-0001-7521-4503 Ochando, M. A.], Medina, F., [https://orcid.org/0000-0002-5881-1442 McCarthy K. J.], [https://orcid.org/0000-0003-0891-0941 Pastor, I.], [https://orcid.org/0000-0003-2101-0112 Liniers M.] and the TJ-II team, Laboratorio Nacional de Fusion, CIEMAT (Spain)

== Details of contact person at LNF ==
belen.lopez.miranda@ciemat.es

== Description of the activity ==
'''Motivation.'''

The study of the impurity behaviour in fusion plasmas is crucial for its performance and the understanding of its transport. Effective ion charge, Zeff, is one of the basic plasma parameters that estimate impurity content in high-temperature plasmas and its profile is essential for studying impurity transport in the plasma core.

Several methods have been implemented to evaluate the Zeff in different fusion devices, such as visible bremsstrahlung (VB) [1, 2], plasma resistivity [3], soft X-ray emission [4], or neutron flux [5]. Whereas in tokamak plasmas several methods are available to estimate the plasma Zeff, in stellarator devices, without significant current, only bremsstrahlung measurements in visible and soft X-ray ranges can be used for this purpose. Therefore, in the LHD and Wendelstein-7X stellarator devices, the Zeff has been determined from the spectrum of continuous radiation in the visible range [6, 7]. But, because the emissivity of the bremsstrahlung radiation is weak in the visible range, using the VB to estimate the visible Zeff is challenging. Previous attempts for measuring the Zeff profiles in TJ-II plasmas using VB profiles [8, 9, 10] provided unrealistic Zeff values much higher than those estimated by soft X-rays measurements. Accurate deduction of Zeff in ECRH plasma scenarios was possible with an absolutely calibrated measurement of the emissivity and electron density and temperature in a visible range where e-i bremsstrahlung was the dominant source of light [11].

'''Proposal.'''

In this work, we propose to study the emission from bremsstrahlung in relatively high-temperature fusion research plasmas created with ECRH and NBI and to measure the Zeff profile by scanning the VB. A general view of the impurity content will be obtained recording spectra between 200 to 900 nm with a PMA spectrometer and the spectral scanning system will be employed to record the VB signals. We will employ the previous system described in [11] upgraded with a plan-achromatic doublet; also, reducing the scanning mirror velocity will maximize the signal to avoid optical aberrations. The effect of the NBI overlapped with ECRH will be studied and the effect of NBI 1 and NBI 2 will be compared. In order to minimize the impurities in TJ-II plasmas, we need a fresh boronizated/lithiumizated wall.

== International or National funding project or entity ==
This work was funded by the projects from the Spanish Ministerio de Ciencia e Innovación RTI2018-100835-B-I00 (MCIU/AEI/FEDER, UE) and PID2020-116599RB-I00.

== Description of required resources ==

'''Required resources:'''
* Number of plasma discharges or days of operation: 3 days

* Essential diagnostic systems: spectral scanning system, Bolometric arrays, X-Ray detectors, VUV spectrometer, Thomson Scattering, Doppler reflectometer.

* Type of plasmas (heating configuration): standard configuration (100_44_64), ECRH, and NBI plasmas, this scenario requires a constant high line averaged density (0.9×1019 m-3), similar to 48223.

* Specific requirements on wall conditioning if any: fresh-lithiated wall.

* External users: need a local computer account for data access: no

* Any external equipment to be integrated? Provide description and integration needs:

== Preferred dates and degree of flexibility ==
Preferred dates: (format dd-mm-yyyy)


== References ==
<references />
[1] Chen, Y., Wu, Z., Gao, W., Ti, A., Zhang, L. et al., (2015). Application of visible bremsstrahlung to Zeff measurement on the Experimental Advanced Superconducting Tokamak. Rev. Sci. Instrum. 86, [023509]. https://aip.scitation.org/doi/10.1063/1.4908200

[2] Morita, S. y Baldzuhn, J., (1994) Max-Planck-Institut für Plasmaphysik, Garching, Germany, IPP Report No. III/199.

[3] Anderson, J. K., (2001). Measurement of the electrical resistivity profile in the Madison Symmetric Torus (Ph.D. Thesis). University of Wisconsin-Madison, (USA).
http://plasma.physics.wisc.edu/uploadedfiles/theses/anderson_thesis_2001.pdf

[4] Galante, M. E., Reusch, L. M., Den Hartog, D. J., Franz P., Johnson, J. R. et al., (2015). Determination of Zeff by Integrating Measurements from X-ray Tomography and Charge Exchange Recombination Spectroscopy, Nucl. Fusion 55, [123016].
https://doi.org/10.1088/0029-5515/55/12/123016

[5] Eriksson, J., Hellesen, C., Conroy, S., Ericsson, G., Hjalmarsson, A. et al., (2013). Deuterium Beam Ion Diffusion in JET H-mode Plasmas Studied with Transport Modelling and Neutron Diagnostics, 13th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems, Beijing, China. From:
http://www.euro-fusionscipub.org/wp-content/uploads/2014/11/EFDP13042.pdf

[6] Zhou, H. Y. Moriota, S., Goto, M. and Dong, C. F., (2010). Zeff profile diagnostics using visible bremsstrahlung continuum for nonaxisymmetric plasmas with finite  in large helical Device. J. Appl. Phys. 107, [053306]
http://dx.doi.org/10.1063/1.3326970

[7] Krychowiak, M., Dodt, D., Dreier, H., König, R. y Wolf, R., (2008). Development of a virtual Zeff diagnostic for the W7-X stellarator. Rev. Sci. Instrum. 79, [10F512]. https://doi.org/10.1063/1.2956826

[8] Baciero, A., Zurro, B. et al., Proc. 30th EPS Conf., St. Petersburg, 7-11 July 2003 ECA Vol. 27A, P-2.80.

[9] Baciero, A., Zurro, B. et al, Proc. 34th EPS Conf., Warsaw, July, 2007 ECA Vol.31F, P-5.089.

[10] López-Miranda, B., Baciero, A., Zurro, B. et al., (2016). Proc. 43rd EPS Conf., Leuven, Belgium, July, 2016 Vol. 40A ISBN: 2-914771-99-1.

[11] López-Miranda, B., (2021). Study of the impurities and continuous radiation in the visible spectral range by means of spectroscopic techniques and lasers in the TJ-II stellarator. (Ph.D. Thesis). Universidad Complutense de Madrid (Spain).

<hr>
[[TJ-II:Experimental proposals|Back to list of experimental proposals]]

[[Category:TJ-II internal documents]]
[[Category:TJ-II experimental proposals Spring 2022]]

TJ-II: Zeff measurement using visible bremsstrahlung emissions with NBI heating

2021-09-30T11:55:33Z

Belenlmiranda: Created page with "== Experimental campaign == Autumn 2021 == Proposal title == '''Zeff measurement using visible bremsstrahlung emissions with NBI heating''' == Name and affiliation of propon..."

== Experimental campaign ==
Autumn 2021

== Proposal title ==
'''Zeff measurement using visible bremsstrahlung emissions with NBI heating'''

== Name and affiliation of proponent ==
López-Miranda, B., Baciero, A., Ochando, M. A., Medina, F., McCarthy, K. J., Pastor, I., Liniers M. and the TJ-II team,
Laboratorio Nacional de Fusion, CIEMAT (Spain)

== Details of contact person at LNF ==
belen.lopez.miranda@ciemat.es

== Description of the activity ==
Motivation.

The study of the impurity behaviour in fusion plasmas is crucial for its performance and the understanding of its transport. Effective ion charge, Zeff, is one of the basic plasma parameters that estimates impurity content in high-temperature plasmas and its profile is essential for studying impurity transport in the plasma core.

Several methods have been implemented to evaluate the Zeff in different fusion devices, such as visible bremsstrahlung (VB) [1, 2], plasma resistivity [3], soft X-ray emission [4], or neutron flux [5]. Whereas in tokamak plasmas several methods are available to estimate the plasma Zeff, in stellarator devices, without significant current, only bremsstrahlung measurements in visible and soft X-ray ranges can be used for this purpose. Therefore, in the LHD and Wendelstein-7X stellarator devices, the Zeff has been determined from the spectrum of continuous radiation in the visible range [6, 7]. But, because the emissivity of the bremsstrahlung radiation is weak in the visible range, using the VB to estimate the visible Zeff is challenging. Previous attempts for measuring the Zeff profiles in TJ-II plasmas using VB profiles [8, 9, 10] provided unrealistic Zeff values much higher than those estimated by soft X-rays measurements. Accurate deduction of Zeff in ECRH plasma scenarios was possible with an absolutely calibrated measurement of the emissivity and electron density and temperature in a visible range where e-i bremsstrahlung was the dominant source of light [11].

Proposal.

In this work, we propose to study the emission from bremsstrahlung in relatively high-temperature fusion research plasmas created with ECRH and NBI and to measure the Zeff profile by scanning the VB. A general view of the impurity content will be obtained recording spectra between 200 to 900 nm with a PMA spectrometer and the spectral scanning system will be employed to record the VB signals. We will employ the previous system described in [11] upgraded with a plan-achromatic doublet; also, reducing the scanning mirror velocity will maximize the signal to avoid optical aberrations. The effect of the NBI overlapped with ECRH will be studied and the effect of NBI 1 and NBI 2 will be compared. In order to minimize the impurities in TJ-II plasmas, we need a fresh boronizated/lithiumizated wall.

== International or National funding project or entity ==
This work was funded by the projects from the Spanish Ministerio de Ciencia e Innovación RTI2018-100835-B-I00 (MCIU/AEI/FEDER, UE) and PID2020-116599RB-I00.

== Description of required resources ==
Required resources:
* Number of plasma discharges or days of operation: 3 days

* Essential diagnostic systems: spectral scanning system, Bolometric arrays, X-Ray detectors, VUV spectrometer, Thomson Scattering, Doppler reflectometer.

* Type of plasmas (heating configuration): standard configuration (100_44_64), ECRH, and NBI plasmas, this scenario requires a constant high line averaged density (0.9×1019 m-3), similar to 48223.

* Specific requirements on wall conditioning if any: fresh-lithiated wall.

* External users: need a local computer account for data access: no

* Any external equipment to be integrated? Provide description and integration needs:

== Preferred dates and degree of flexibility ==
Preferred dates: (format dd-mm-yyyy)


== References ==
<references />
[1] Chen, Y., Wu, Z., Gao, W., Ti, A., Zhang, L. et al., (2015). Application of visible bremsstrahlung to Zeff measurement on the Experimental Advanced Superconducting Tokamak. Rev. Sci. Instrum. 86, [023509]. https://aip.scitation.org/doi/10.1063/1.4908200

[2] Morita, S. y Baldzuhn, J., (1994) Max-Planck-Institut für Plasmaphysik, Garching, Germany, IPP Report No. III/199.

[3] Anderson, J. K., (2001). Measurement of the electrical resistivity profile in the Madison Symmetric Torus (Ph.D. Thesis). University of Wisconsin-Madison, (USA).
http://plasma.physics.wisc.edu/uploadedfiles/theses/anderson_thesis_2001.pdf

[4] Galante, M. E., Reusch, L. M., Den Hartog, D. J., Franz P., Johnson, J. R. et al., (2015). Determination of Zeff by Integrating Measurements from X-ray Tomography and Charge Exchange Recombination Spectroscopy, Nucl. Fusion 55, [123016].
https://doi.org/10.1088/0029-5515/55/12/123016

[5] Eriksson, J., Hellesen, C., Conroy, S., Ericsson, G., Hjalmarsson, A. et al., (2013). Deuterium Beam Ion Diffusion in JET H-mode Plasmas Studied with Transport Modelling and Neutron Diagnostics, 13th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems, Beijing, China. From:
http://www.euro-fusionscipub.org/wp-content/uploads/2014/11/EFDP13042.pdf

[6] Zhou, H. Y. Moriota, S., Goto, M. and Dong, C. F., (2010). Zeff profile diagnostics using visible bremsstrahlung continuum for nonaxisymmetric plasmas with finite  in large helical Device. J. Appl. Phys. 107, [053306]
http://dx.doi.org/10.1063/1.3326970

[7] Krychowiak, M., Dodt, D., Dreier, H., König, R. y Wolf, R., (2008). Development of a virtual Zeff diagnostic for the W7-X stellarator. Rev. Sci. Instrum. 79, [10F512]. https://doi.org/10.1063/1.2956826

[8] Baciero, A., Zurro, B. et al., Proc. 30th EPS Conf., St. Petersburg, 7-11 July 2003 ECA Vol. 27A, P-2.80.

[9] Baciero, A., Zurro, B. et al, Proc. 34th EPS Conf., Warsaw, July, 2007 ECA Vol.31F, P-5.089.

[10] López-Miranda, B., Baciero, A., Zurro, B. et al., (2016). Proc. 43rd EPS Conf., Leuven, Belgium, July, 2016 Vol. 40A ISBN: 2-914771-99-1.

[11] López-Miranda, B., (2021). Study of the impurities and continuous radiation in the visible spectral range by means of spectroscopic techniques and lasers in the TJ-II stellarator. (Ph.D. Thesis). Universidad Complutense de Madrid (Spain).

<hr>
[[TJ-II:Experimental proposals|Back to list of experimental proposals]]

[[Category:TJ-II internal documents]]
[[Category:TJ-II experimental proposals Autumn 2021]]

TJ-II: Impurity injection by laser blow-off (LBO): Confinement and transport studies of high Z impurity injection by LBO in ion-root regime discharges

2021-09-30T11:39:23Z

Belenlmiranda: Created page with "== Experimental campaign == Autumn 2021 == Proposal title == '''Impurity injection by laser blow-off (LBO): Confinement and transport studies of high Z Impurity injection by ..."

== Experimental campaign ==
Autumn 2021

== Proposal title ==
'''Impurity injection by laser blow-off (LBO): Confinement and transport studies of high Z Impurity injection by LBO in ion-root regime discharges'''

== Name and affiliation of proponent ==
López-Miranda, B., Baciero, A., Ochando, M. A., Medina, F., McCarthy, K. J., García-Regaña, J. M., Velasco, J. L., Pastor, I. HIBP group and the TJ-II team,
Laboratorio Nacional de Fusion, CIEMAT (Spain)

== Details of contact person at LNF ==

belen.lopez.miranda@ciemat.es

== Description of the activity ==
Motivation.

In previous works [1, 2, 3], we have studied impurity (BC, LiF, BN, Fe) transport mainly in ECRH plasmas heated by ECR [2]. Transport has been measured in low-density regimes (injecting controlled amounts of B or Fe impurities), where the radial electric field is positive, Er > 0, and the plasma is in the electron root. Several limitations were found to inject heavy impurities (Fe, W), particularly in high-density regimes, due to the intrinsic limitation of the cut-off density that interrupts the discharge and the lack of density control due to the absence of a true plateau. Near the value of the density where the transition to a positive electric field occurs (from electron-root to ion-root), an increase in confinement time was observed, but in those discharges with higher densities, the estimated confinement time was much longer than the duration of the discharge and it was not possible to deduce any value for the confinement time. Here we try to study the confinement time in ion-root regimes using LBO in order to investigate the behaviour of heavy impurities injected both in electron-root regimes and in ion-root regimes TJ-II plasmas. We also would compare the experimental results with the predictions of neoclassical transport in order to figure out the mechanisms involved in these processes.

Proposal.

We plan to inject heavy impurities (Fe, W) by means of LBO into TJ-II discharges. This scenario requires a constant high line averaged density (0.9×1019 m-3), similar to 48223. For this, the confinement times of the impurities and the transport coefficients will be estimated after injecting impurities of different masses. The confinement times of the impurities will be deduced from the decay of different radiation signals. Thanks to the reconstructions of bolometric and X-ray radiation profiles [4, 5], an attempt will be made to deduce the diffusion (D) and transport (v) coefficients that account for these emissions by using the STRAHL [6] transport code. Finally, since neoclassical transport simulations also predict differences in transport in different regimes [7], we would compare these results with the simulations of the EUTERPE [8] code used to estimate neoclassical transport.

Discharges and diagnostics.

We need discharges with good control of plasma density discharges in a fixed magnetic configuration (100_44_64). We wish plasma electron densities sufficiently high to obtain good Thomson Scattering profiles before and after impurity injection. Main diagnostics, apart from standard monitors, will be radiation diagnostics (bolometers, X-ray detectors, VUV spectrometer, etc.), and we also need the values of Er with HIBP system and Doppler reflectometer. It is necessary to obtain the ion temperature profiles by means of NPA system. A good plasma-wall condition is also required, so we prefer a fresh-lithiated wall.
The transport properties of a selected group of discharges will be analyzed with the transport code STRAHL. The values of D and v coefficients obtained by STRAHL will be compared with neoclassical simulations in DKES/EUTERPE or similar codes performed by the TJ-II theoretical group.

== International or National funding project or entity ==
This work was funded by the projects from the Spanish Ministerio de Ciencia e Innovación RTI2018-100835-B-I00 (MCIU/AEI/FEDER, UE) and PID2020-116599RB-I00.

== Description of required resources ==
Required resources:
* Number of plasma discharges or days of operation: 3 days

* Essential diagnostic systems: Nd:YAG laser, spectroscopic system, Bolometric arrays, X-Ray detectors, VUV spectrometer, Thomson Scattering, NPA system, Doppler reflectometer, HIBP.
* Type of plasmas (heating configuration): standard configuration (100_44_64), ECRH and NBI, this scenario requires a constant high line averaged density (0.9×1019 m-3), similar to 48223.

* Specific requirements on wall conditioning if any: fresh-lithiated wall.

* External users: need a local computer account for data access: no

* Any external equipment to be integrated? Provide description and integration needs:

== Preferred dates and degree of flexibility ==
Preferred dates: (format dd-mm-yyyy)


== References ==
<references />
[1] Zurro B, Hollmann E, Baciero A, Ochando MA, Medina F, McCarthy KJ et al., (2011). Transport studies using laser blow-off injection of low-Z trace impurities injected into the TJ-II stellarator, Nuclear Fusion 51 (2011) 063015 (9pp).

[2] Zurro B., Hollmann, E. M., Baciero, A., Ochando, M. A., Medina, F. et al., (2014). Studying the impurity charge and main ion mass dependence of impurity confinement in ECR-heated TJ-II stellarator, Plasma Phys. Control. Fusion 56, [124007].

https://doi.org/10.1088/0741-3335/56/12/124007

[3] Zurro, B., Velasco, J. L., Hollmann, E. M., Baciero, A., et al, (2015). Transport analysis of impurities injected by laser blow-off in ECRH and NBI heated plasmas of TJ-II, Proc. EPS 2015. Lisbon.

[4] Medina, F., Pedrosa, M. A., Ochando, M. A., Rodríguez-Rodrigo, L., Hidalgo, C. et al., (2001). Filamentary current detection in stellarator plasmas. Rev. Sci. Instrum. 72, [471]. https://doi.org/10.1063/1.1310579

[5] Ochando, M. A., Medina, F., Zurro, B., Baciero, A., McCarthy, K. J. et al., (2006). Up-down and in-out asymmetry monitoring based on broadband radiation detectors. Fusion Sci. Tech. 50, [31]. https://doi.org/10.13182/FST06-A1252

[6] Dux, R., Neu, R., Peeters, A. G., Pereverzev, G., Mück, A. et al., (2003). Plasma Phys. Control. Fusion 45, [1815]. https,//doi.org/10.1088/0741-3335/45/9/317

[7] Velasco J. L., Calvo, I., Satake, S., Alonso, A., Nunami, M. et al., (2017). Moderation of neoclassical impurity accumulation in high-temperature plasmas of helical devices, Nucl. Fusion, 57, [016016]. https://doi.org/10.1088/0029-5515/57/1/016016

[8] García-Regaña, J. M., Beidler, C. D., Kleiber, R., Helander, P., Mollen, A. et al., (2017). Electrostatic potential variation on the flux surface and its impact on impurity transport. Nucl. Fusion 57, [056004]. https://doi.org/10.1088/1741-4326/aa5fd5

<hr>
[[TJ-II:Experimental proposals|Back to list of experimental proposals]]

[[Category:TJ-II internal documents]]
[[Category:TJ-II experimental proposals Autumn 2021]]

TJ-II:Impurity transport studies by LILA-TOF detection. A Lithium Laser-Ablation based Time-of-Flight (LILA-TOF) diagnostic for measuring plasma edge ion temperature and toroidal plasma rotation

2021-09-30T11:28:05Z

Belenlmiranda: Created page with "== Experimental campaign == Autumn 2021 == Proposal title == '''Impurity transport studies by LILA-TOF detection: A Lithium Laser-Ablation based Time-of-Flight (LILA-TOF) dia..."

== Experimental campaign ==
Autumn 2021

== Proposal title ==
'''Impurity transport studies by LILA-TOF detection: A Lithium Laser-Ablation based Time-of-Flight (LILA-TOF) diagnostic for measuring plasma edge ion temperature and toroidal plasma rotation'''

== Name and affiliation of proponent ==
López-Miranda, B., Tabarés, F., Baciero, A., Ochando, M. A., Medina, F., Tafalla. D., McCarthy, K. J.,
Laboratorio Nacional de Fusion, CIEMAT (Spain)

Suggested format:

[https://orcid.org/0000-0000-0000-0000 John Doe], University of Ivory Tower

== Details of contact person at LNF ==
belen.lopez.miranda@ciemat.es
== Description of the activity ==
Background:

Although several methods for the measurement of Ti at the edge of TJ-II have been tried (RFA, He beam, Doppler spectroscopy…) [1-7] no systematic recording of this important parameter has been achieved so far. A new method for studying the thermalization and transport of injected impurities at the edge of hot plasma, (considering the last closed magnetic surface, the free path is between 1 to 2 cm approx.) under no perturbative conditions, was developed [8] using a Nd:YAG laser called Lithium Laser-Ablation based Time-of-Flight (LILA-TOF) technique. Ion temperatures deduced from the application of this technique (25 eV in the edge) are in good agreement with previous measurements in TJ-II by Retarding Field Analyzer (RFA) (17-21 eV in the SOL) [9].

Description:

In the proposed technique, a Nd:YAG laser is used to ablate Li from the lithiated wall of the stellarator TJ-II. While the laser pulse allows for the analysis of the released species through Laser-Induced Breakdown Spectroscopy (LIBS) [10], its laser pulse also provides a time reference for the Time-of-Flight (TOF) measurements of the Li+ ions performed. This is done by positioning light detection systems sensitive to an intense Li II spectral line at different toroidal locations away from such a source. TOF times of tens to hundreds of microseconds are recorded. Fast recording of the TOF of the Li+ emission toroidally away from the source will provide the energy distribution of the thermalized particles.
Then, by de-convolving the shape of the recorded light pulse, the velocity distribution of the lithium-ion during its thermalization with the background plasma can be extracted. From this velocity distribution, the ion temperature of the background ions and the toroidal rotation at the plasma periphery can be deduced. The viability of injecting Li using LIBS and recording the lithium traces of the plasma-generated Li+ ions to study ion toroidal, and, consequently, deducing the TOF using its propagation has been demonstrated [10]. The preliminary values of Ti and vrot deduced are consistent with those measured with other diagnostics in TJ-II. Several limitations have been identified as the influence of plasma toroidal rotation. This parameter has a direct impact on the shape of the TOF trace. Consequently, this proposal is oriented to obtain a more accurate estimation of the rotation and Ti would be performed by simultaneously recording the lithium traces at two toroidal locations, on opposite sides of the injection point whenever available. Reproducible plasmas are required to compare the Ti obtained using TOF measurements in the different TJ-II monitors located in opposite sectors.

== International or National funding project or entity ==
This work was funded by the projects from the Spanish Ministerio de Ciencia e Innovación RTI2018-100835-B-I00 (MCIU/AEI/FEDER, UE) and PID2020-116599RB-I00.
== Description of required resources ==
Required resources:

 Number of plasma discharges or days of operation: 3 days

 Essential diagnostic systems: Nd:YAG laser, spectroscopic system, Bolometric arrays, X-Ray detectors, VUV spectrometer, Thomson Scattering, Doppler reflectometer.

 Type of plasmas (heating configuration): standard configuration (100_44_64), ECRH, this scenario requires a constant high line averaged density, similar to March 24th, 2021.

 Specific requirements on wall conditioning if any: fresh-lithiated wall.

 External users: need a local computer account for data access: no

 Any external equipment to be integrated? Provide description and integration needs:

== Preferred dates and degree of flexibility ==
Preferred dates: (format dd-mm-yyyy)


== References ==
<references />
[1] Kocan, K., Gunn, J. P., Komm, M., et al. 2008. Rev. Sci. Instr. 79 073502

[2] Katsumata, I. and Okazaki, M., 1967. Jpn. J. Appl. Phys 6 123

[3] Zurro, B., Vega, J., Castejón, F., et al. 1992. Phys Rev Lett. 69 2919

[4] McCarthy, K. J., Zurro, B., Balbín R., et al., 2003. Europhys. Lett., 63 (1), 49-55

[5] Pitcher, C. S. and Stangeby, P. C., 1981. Plasma Phys. Control. Fusion 31 1305

[6] Tabarés, F. L., Tafalla, D., Ferreira J. A., et al. 2010. Rev. Sci. Instr. 81 10D708

[7] Tabarés, F. L. and Tafalla, D., 2015. Nucl. Fus. 55 013020

[8] López-Miranda, B., Tabarés, F. L., McCarthy, K. J., Baciero, A., D. Tafalla, F. L., et al. 2021. Plasma Phys. Control. Fusion, submitted.

[9] Nedzelskiy I. S., Silva C., Fernández H., et al., 2009. Probl. Atom. Sci. Tech. 1, 174

[10] López-Miranda, B., Zurro, B., Baciero, et al., (2018). Investigation of the toroidal propagation of lithium injected by LIBS into TJ-II plasmas to measure edge ion temperature. EPS Conference Prague.

<hr>
[[TJ-II: Experimental proposals|Back to list of experimental proposals]]

[[Category:TJ-II internal documents]]
[[Category:TJ-II experimental proposals Autumn 2021]]