TJ-II:Turbulence properties near a rational surface - Revision history

Admin: /* Description of required resources */

2022-03-11T10:52:46Z

Description of required resources

← Older revision		Revision as of 12:52, 11 March 2022
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	Required resources:		Required resources:
	* Dynamic iota scan between configurations 100_40 and 100_44		* Dynamic iota scan between configurations 100_40 and 100_44
			* OH current control
	* Biasing at fixed voltage [-300, -150, 0, 150, 300] V		* Biasing at fixed voltage [-300, -150, 0, 150, 300] V
	* Number of plasma discharges or days of operation: 30 discharges, 1 day		* Number of plasma discharges or days of operation: 30 discharges, 1 day

Admin: /* Description of the activity */

2022-03-10T08:58:26Z

Description of the activity

← Older revision		Revision as of 10:58, 10 March 2022
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	In the present experiment, we therefore plan to repeat the iota scan experiments while applying a radial electric field, induced via probe biasing.		In the present experiment, we therefore plan to repeat the iota scan experiments while applying a radial electric field, induced via probe biasing.

	The plan is to scan iota between configurations 100_40 ~~(or 100_38)~~ and 100_44, while the B and D Langmuir probes are located at <math>\rho \simeq 0.85-0.90</math> (the reason being that this scan will move the important 8/5 rational surface across the Langmuir probe location, based on the results from the latest paper cited). The applied voltage to the biasing probe will be [-300, -150, 0, 150, 300], making 5 discharges at each voltage to verify reproducibility<ref>B.Ph. van Milligen, B.A. Carreras, L. García, G. Grenfell, I. Voldiner, C. Hidalgo, and the TJ-II Team. ''The impact of radial electric fields and plasma rotation on intermittence in TJ-II''. [[doi:10.1088/1361-6587/ac54e9\|Plasma Phys. Control. Fusion, 2021]].</ref>.		The plan is to scan iota between configurations 100_40 and 100_44, while the B and D Langmuir probes are located at <math>\rho \simeq 0.85-0.90</math> (the reason being that this scan will move the important 8/5 rational surface across the Langmuir probe location, based on the results from the latest paper cited). The applied voltage to the biasing probe will be [-300, -150, 0, 150, 300], making 5 discharges at each voltage to verify reproducibility<ref>B.Ph. van Milligen, B.A. Carreras, L. García, G. Grenfell, I. Voldiner, C. Hidalgo, and the TJ-II Team. ''The impact of radial electric fields and plasma rotation on intermittence in TJ-II''. [[doi:10.1088/1361-6587/ac54e9\|Plasma Phys. Control. Fusion, 2021]].</ref>.
	Apart from intermittence, we will quantify all other turbulence parameters that can be measured by the probes: <math>V_f, I_{\rm sat}, E_r, E_\theta, v_\theta, \Gamma</math>, the RMS of various quantities, long-range correlations between probes B and D, cross phase (between <math>E_\theta, I_{\rm sat}</math>), etc.<ref>B. van Milligen, B. Carreras, I. Voldiner, U. Losada, C. Hidalgo, and the TJ-II Team. ''Causality, intermittence and crossphase evolution during confinement transitions in the TJ-II stellarator''. [[doi:10.1063/5.0057791\|Phys. Plasmas, 28:092302, 2021]].</ref>		Apart from intermittence, we will quantify all other turbulence parameters that can be measured by the probes: <math>V_f, I_{\rm sat}, E_r, E_\theta, v_\theta, \Gamma</math>, the RMS of various quantities, long-range correlations between probes B and D, cross phase (between <math>E_\theta, I_{\rm sat}</math>), etc.<ref>B. van Milligen, B. Carreras, I. Voldiner, U. Losada, C. Hidalgo, and the TJ-II Team. ''Causality, intermittence and crossphase evolution during confinement transitions in the TJ-II stellarator''. [[doi:10.1063/5.0057791\|Phys. Plasmas, 28:092302, 2021]].</ref>

Admin at 08:56, 10 March 2022

2022-03-10T08:56:39Z

← Older revision		Revision as of 10:56, 10 March 2022
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	In the present experiment, we therefore plan to repeat the iota scan experiments while applying a radial electric field, induced via probe biasing.		In the present experiment, we therefore plan to repeat the iota scan experiments while applying a radial electric field, induced via probe biasing.

	The plan is to scan iota between configurations 100_40 (or 100_38) and 100_44, while the B and D Langmuir probes are located at <math>\rho \simeq 0.85-0.90</math> (the reason being that this scan will move the important 8/5 rational surface across the Langmuir probe location, based on the results from the latest paper cited). The applied voltage to the biasing probe will be [-300, -150, 0, 150, 300], making 5 discharges at each voltage to verify reproducibility<ref>B.Ph. van Milligen, B.A. Carreras, L. ~~Garc ́ıa~~, G. Grenfell, I. Voldiner, C. Hidalgo, and the TJ-II Team. ''The impact of radial electric fields and plasma rotation on intermittence in TJ-II''. [[doi:10.1088/1361-6587/ac54e9\|Plasma Phys. Control. Fusion, 2021]].</ref>.		The plan is to scan iota between configurations 100_40 (or 100_38) and 100_44, while the B and D Langmuir probes are located at <math>\rho \simeq 0.85-0.90</math> (the reason being that this scan will move the important 8/5 rational surface across the Langmuir probe location, based on the results from the latest paper cited). The applied voltage to the biasing probe will be [-300, -150, 0, 150, 300], making 5 discharges at each voltage to verify reproducibility<ref>B.Ph. van Milligen, B.A. Carreras, L. García, G. Grenfell, I. Voldiner, C. Hidalgo, and the TJ-II Team. ''The impact of radial electric fields and plasma rotation on intermittence in TJ-II''. [[doi:10.1088/1361-6587/ac54e9\|Plasma Phys. Control. Fusion, 2021]].</ref>.
	Apart from intermittence, we will quantify all other turbulence parameters that can be measured by the probes: <math>V_f, I_{\rm sat}, E_r, E_\theta, v_\theta, \Gamma</math>, the RMS of various quantities, long-range correlations between probes B and D, cross phase (between <math>E_\theta, I_{\rm sat}</math>), etc.<ref>B. van Milligen, B. Carreras, I. Voldiner, U. Losada, C. Hidalgo, and the TJ-II Team. ''Causality, intermittence and crossphase evolution during confinement transitions in the TJ-II stellarator''. [[doi:10.1063/5.0057791\|Phys. Plasmas, 28:092302, 2021]].</ref>		Apart from intermittence, we will quantify all other turbulence parameters that can be measured by the probes: <math>V_f, I_{\rm sat}, E_r, E_\theta, v_\theta, \Gamma</math>, the RMS of various quantities, long-range correlations between probes B and D, cross phase (between <math>E_\theta, I_{\rm sat}</math>), etc.<ref>B. van Milligen, B. Carreras, I. Voldiner, U. Losada, C. Hidalgo, and the TJ-II Team. ''Causality, intermittence and crossphase evolution during confinement transitions in the TJ-II stellarator''. [[doi:10.1063/5.0057791\|Phys. Plasmas, 28:092302, 2021]].</ref>

Admin at 08:55, 10 March 2022

2022-03-10T08:55:32Z

← Older revision		Revision as of 10:55, 10 March 2022
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	== Description of the activity ==		== Description of the activity ==
	In previous work, we have established that the intermittence parameter C(1) varies in a systematic way near rational surfaces<ref>B. Carreras, L. García, J. Nicolau, B. van Milligen, U. Hoefel, M. Hirsch, and the TJ-II and W7-X Teams. ''Intermittence and turbulence in fusion devices''. Plasma Phys. Control. Fusion, 62:025011, 2020.</ref>. This was found to be the case both in a numerical model of resistive MHD turbulence, and confirmed using data from the W7-X stellarator. Hence, the intermittence parameter provides an indirect diagnostic of the magnetic configuration.		In previous work, we have established that the intermittence parameter C(1) varies in a systematic way near rational surfaces<ref>B. Carreras, L. García, J. Nicolau, B. van Milligen, U. Hoefel, M. Hirsch, and the TJ-II and W7-X Teams. ''Intermittence and turbulence in fusion devices''. [[doi:10.1088/1361-6587/ab57f9\|Plasma Phys. Control. Fusion, 62:025011, 2020]].</ref>. This was found to be the case both in a numerical model of resistive MHD turbulence, and confirmed using data from the W7-X stellarator. Hence, the intermittence parameter provides an indirect diagnostic of the magnetic configuration.

	In more recent work, the iota scan experiments of 2013<ref>B.Ph. van Milligen et al., ''Parallel and perpendicular turbulence correlation length in the TJ-II stellarator''. Nucl. Fusion, 53:093025 (2013)</ref> were revisited, and a remarkably detailed confirmation of this phenomenon was obtained<ref>B. P. van Milligen, B. Carreras, L. García, and C. Hidalgo. ''The localization of low order rational surfaces based on the intermittence parameter in the TJ-II stellarator''. Nucl. Fusion, 60:056010, 2020.</ref>. The latter paper also suggested that a radial electric field (i.e., poloidal rotation) may affect the intermittence parameter significantly.		In more recent work, the iota scan experiments of 2013<ref>B.Ph. van Milligen et al., ''Parallel and perpendicular turbulence correlation length in the TJ-II stellarator''. [[doi:10.1088/0029-5515/53/9/093025\|Nucl. Fusion, 53:093025 (2013)]]</ref> were revisited, and a remarkably detailed confirmation of this phenomenon was obtained<ref>B. P. van Milligen, B. Carreras, L. García, and C. Hidalgo. ''The localization of low order rational surfaces based on the intermittence parameter in the TJ-II stellarator''. [[doi:10.1088/1741-4326/ab79cc\|Nucl. Fusion, 60:056010, 2020]].</ref>. The latter paper also suggested that a radial electric field (i.e., poloidal rotation) may affect the intermittence parameter significantly.
	In the present experiment, we therefore plan to repeat the iota scan experiments while applying a radial electric field, induced via probe biasing.		In the present experiment, we therefore plan to repeat the iota scan experiments while applying a radial electric field, induced via probe biasing.

	The plan is to scan iota between configurations 100_40 (or 100_38) and 100_44, while the B and D Langmuir probes are located at <math>\rho \simeq 0.85-0.90</math> (the reason being that this scan will move the important 8/5 rational surface across the Langmuir probe location, based on the results from the latest paper cited). The applied voltage to the biasing probe will be [-300, -150, 0, 150, 300], making 5 discharges at each voltage to verify reproducibility.		The plan is to scan iota between configurations 100_40 (or 100_38) and 100_44, while the B and D Langmuir probes are located at <math>\rho \simeq 0.85-0.90</math> (the reason being that this scan will move the important 8/5 rational surface across the Langmuir probe location, based on the results from the latest paper cited). The applied voltage to the biasing probe will be [-300, -150, 0, 150, 300], making 5 discharges at each voltage to verify reproducibility<ref>B.Ph. van Milligen, B.A. Carreras, L. Garc ́ıa, G. Grenfell, I. Voldiner, C. Hidalgo, and the TJ-II Team. ''The impact of radial electric fields and plasma rotation on intermittence in TJ-II''. [[doi:10.1088/1361-6587/ac54e9\|Plasma Phys. Control. Fusion, 2021]].</ref>.
	Apart from intermittence, we will quantify all other turbulence parameters that can be measured by the probes: <math>V_f, I_{\rm sat}, E_r, E_\theta, v_\theta, \Gamma</math>, the RMS of various quantities, long-range correlations between probes B and D, cross phase (between <math>E_\theta, I_{\rm sat}</math>), etc.<ref>B. van Milligen, B. Carreras, I. Voldiner, U. Losada, C. Hidalgo, and the TJ-II Team. ''Causality, intermittence and crossphase evolution during confinement transitions in the TJ-II stellarator''. Phys. Plasmas, 28:092302, 2021.</ref>		Apart from intermittence, we will quantify all other turbulence parameters that can be measured by the probes: <math>V_f, I_{\rm sat}, E_r, E_\theta, v_\theta, \Gamma</math>, the RMS of various quantities, long-range correlations between probes B and D, cross phase (between <math>E_\theta, I_{\rm sat}</math>), etc.<ref>B. van Milligen, B. Carreras, I. Voldiner, U. Losada, C. Hidalgo, and the TJ-II Team. ''Causality, intermittence and crossphase evolution during confinement transitions in the TJ-II stellarator''. [[doi:10.1063/5.0057791\|Phys. Plasmas, 28:092302, 2021]].</ref>

	== International or National funding project or entity ==		== International or National funding project or entity ==

Admin: /* Description of required resources */

2022-01-13T09:35:32Z

Description of required resources

← Older revision		Revision as of 11:35, 13 January 2022
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	* Essential diagnostic systems: Langmuir probes		* Essential diagnostic systems: Langmuir probes
	* Desirable diagnostic systems: Doppler reflectometer, HIBP (at similar radial positions as the Langmuir probes)		* Desirable diagnostic systems: Doppler reflectometer, HIBP (at similar radial positions as the Langmuir probes)
	* Type of plasmas (heating configuration): ECRH heated, density constant, below critical density (<math>n_e \simeq 0.6\cdot 10^{19} {\mathrm m}^{-3}</math>)		* Type of plasmas (heating configuration): ECRH heated, density constant, below critical density (<math>n_e^{\rm crit} \simeq 0.6\cdot 10^{19} {\mathrm m}^{-3}</math>)

	== Preferred dates and degree of flexibility ==		== Preferred dates and degree of flexibility ==

Admin: /* Description of required resources */

2022-01-13T09:34:54Z

Description of required resources

← Older revision		Revision as of 11:34, 13 January 2022
Line 26:		Line 26:
	Required resources:		Required resources:
	* Dynamic iota scan between configurations 100_40 and 100_44		* Dynamic iota scan between configurations 100_40 and 100_44
	* Biasing at fixed voltage [-300, -150, 0, 150, 300]		* Biasing at fixed voltage [-300, -150, 0, 150, 300] V
	* Number of plasma discharges or days of operation: 30 discharges, 1 day		* Number of plasma discharges or days of operation: 30 discharges, 1 day
	* Essential diagnostic systems: Langmuir probes		* Essential diagnostic systems: Langmuir probes

Admin: /* Description of the activity */

2022-01-13T09:30:00Z

Description of the activity

← Older revision		Revision as of 11:30, 13 January 2022
Line 17:		Line 17:
	In the present experiment, we therefore plan to repeat the iota scan experiments while applying a radial electric field, induced via probe biasing.		In the present experiment, we therefore plan to repeat the iota scan experiments while applying a radial electric field, induced via probe biasing.

	The plan is to scan iota between configurations 100_40 and 100_44, while the B and D Langmuir probes are located at &rho~~; ≃~~ 0.85 (the reason being that this scan will move the important 8/5 rational surface across the Langmuir probe location, based on the results from the latest paper cited). The applied voltage to the biasing probe will be [-300, -150, 0, 150, 300], making 5 discharges at each voltage to verify reproducibility.		The plan is to scan iota between configurations 100_40 (or 100_38) and 100_44, while the B and D Langmuir probes are located at <math>\rho \simeq 0.85-0.90</math> (the reason being that this scan will move the important 8/5 rational surface across the Langmuir probe location, based on the results from the latest paper cited). The applied voltage to the biasing probe will be [-300, -150, 0, 150, 300], making 5 discharges at each voltage to verify reproducibility.
	Apart from intermittence, we will quantify all other turbulence parameters that can be measured by the probes: <math>V_f, I_{\rm sat}, E_r, E_\theta, v_\theta, \Gamma</math>, the RMS of various quantities, long-range correlations between probes B and D, cross phase (between <math>E_\theta, I_{\rm sat}</math>), etc.<ref>B. van Milligen, B. Carreras, I. Voldiner, U. Losada, C. Hidalgo, and the TJ-II Team. ''Causality, intermittence and crossphase evolution during confinement transitions in the TJ-II stellarator''. Phys. Plasmas, 28:092302, 2021.</ref>		Apart from intermittence, we will quantify all other turbulence parameters that can be measured by the probes: <math>V_f, I_{\rm sat}, E_r, E_\theta, v_\theta, \Gamma</math>, the RMS of various quantities, long-range correlations between probes B and D, cross phase (between <math>E_\theta, I_{\rm sat}</math>), etc.<ref>B. van Milligen, B. Carreras, I. Voldiner, U. Losada, C. Hidalgo, and the TJ-II Team. ''Causality, intermittence and crossphase evolution during confinement transitions in the TJ-II stellarator''. Phys. Plasmas, 28:092302, 2021.</ref>

	== International or National funding project or entity ==		== International or National funding project or entity ==

Admin at 09:28, 13 January 2022

2022-01-13T09:28:08Z

← Older revision		Revision as of 11:28, 13 January 2022
Line 14:		Line 14:
	In previous work, we have established that the intermittence parameter C(1) varies in a systematic way near rational surfaces<ref>B. Carreras, L. García, J. Nicolau, B. van Milligen, U. Hoefel, M. Hirsch, and the TJ-II and W7-X Teams. ''Intermittence and turbulence in fusion devices''. Plasma Phys. Control. Fusion, 62:025011, 2020.</ref>. This was found to be the case both in a numerical model of resistive MHD turbulence, and confirmed using data from the W7-X stellarator. Hence, the intermittence parameter provides an indirect diagnostic of the magnetic configuration.		In previous work, we have established that the intermittence parameter C(1) varies in a systematic way near rational surfaces<ref>B. Carreras, L. García, J. Nicolau, B. van Milligen, U. Hoefel, M. Hirsch, and the TJ-II and W7-X Teams. ''Intermittence and turbulence in fusion devices''. Plasma Phys. Control. Fusion, 62:025011, 2020.</ref>. This was found to be the case both in a numerical model of resistive MHD turbulence, and confirmed using data from the W7-X stellarator. Hence, the intermittence parameter provides an indirect diagnostic of the magnetic configuration.

	In more recent work, the iota scan experiments of 2013<ref>B.Ph. van Milligen et al., Parallel and perpendicular turbulence correlation length in the TJ-II stellarator. Nucl. Fusion, 53:093025 (2013)</ref> were revisited, and a remarkably detailed confirmation of this phenomenon was obtained<ref>B. P. van Milligen, B. Carreras, L. García, and C. Hidalgo. ''The localization of low order rational surfaces based on the intermittence parameter in the TJ-II stellarator''. Nucl. Fusion, 60:056010, 2020.</ref>. The latter paper also suggested that a radial electric field (i.e., poloidal rotation) may affect the intermittence parameter significantly.		In more recent work, the iota scan experiments of 2013<ref>B.Ph. van Milligen et al., ''Parallel and perpendicular turbulence correlation length in the TJ-II stellarator''. Nucl. Fusion, 53:093025 (2013)</ref> were revisited, and a remarkably detailed confirmation of this phenomenon was obtained<ref>B. P. van Milligen, B. Carreras, L. García, and C. Hidalgo. ''The localization of low order rational surfaces based on the intermittence parameter in the TJ-II stellarator''. Nucl. Fusion, 60:056010, 2020.</ref>. The latter paper also suggested that a radial electric field (i.e., poloidal rotation) may affect the intermittence parameter significantly.
	In the present experiment, we therefore plan to repeat the iota scan experiments while applying a radial electric field, induced via probe biasing.		In the present experiment, we therefore plan to repeat the iota scan experiments while applying a radial electric field, induced via probe biasing.

Admin: /* International or National funding project or entity */

2022-01-13T08:36:41Z

International or National funding project or entity

← Older revision		Revision as of 10:36, 13 January 2022
Line 21:		Line 21:

	== International or National funding project or entity ==		== International or National funding project or entity ==
	~~Ministerio de Ciencia, Innovación y Universidades Nº PGC2018-097279-B-I00~~		N/A

	== Description of required resources ==		== Description of required resources ==

Admin: Created page with "== Experimental campaign == Spring 2022 == Proposal title == '''Turbulence properties near a rational surface''' == Name and affiliation of proponent == [https://orcid.org/0..."

2022-01-13T08:32:33Z

Created page with "== Experimental campaign == Spring 2022 == Proposal title == '''Turbulence properties near a rational surface''' == Name and affiliation of proponent == [https://orcid.org/0..."

New page

== Experimental campaign ==
Spring 2022

== Proposal title ==
'''Turbulence properties near a rational surface'''

== Name and affiliation of proponent ==
[https://orcid.org/0000-0001-5344-6274 B.P. van Milligen], [https://orcid.org/0000-0001-6703-7754 I. Voldiner], [https://orcid.org/0000-0001-7921-4690 B.A. Carreras], [https://orcid.org/0000-0002-0736-7855 C. Hidalgo]

== Details of contact person at LNF ==
N/A

== Description of the activity ==
In previous work, we have established that the intermittence parameter C(1) varies in a systematic way near rational surfaces<ref>B. Carreras, L. García, J. Nicolau, B. van Milligen, U. Hoefel, M. Hirsch, and the TJ-II and W7-X Teams. ''Intermittence and turbulence in fusion devices''. Plasma Phys. Control. Fusion, 62:025011, 2020.</ref>. This was found to be the case both in a numerical model of resistive MHD turbulence, and confirmed using data from the W7-X stellarator. Hence, the intermittence parameter provides an indirect diagnostic of the magnetic configuration.

In more recent work, the iota scan experiments of 2013<ref>B.Ph. van Milligen et al., Parallel and perpendicular turbulence correlation length in the TJ-II stellarator. Nucl. Fusion, 53:093025 (2013)</ref> were revisited, and a remarkably detailed confirmation of this phenomenon was obtained<ref>B. P. van Milligen, B. Carreras, L. García, and C. Hidalgo. ''The localization of low order rational surfaces based on the intermittence parameter in the TJ-II stellarator''. Nucl. Fusion, 60:056010, 2020.</ref>. The latter paper also suggested that a radial electric field (i.e., poloidal rotation) may affect the intermittence parameter significantly.
In the present experiment, we therefore plan to repeat the iota scan experiments while applying a radial electric field, induced via probe biasing.

The plan is to scan iota between configurations 100_40 and 100_44, while the B and D Langmuir probes are located at ρ ≃ 0.85 (the reason being that this scan will move the important 8/5 rational surface across the Langmuir probe location, based on the results from the latest paper cited). The applied voltage to the biasing probe will be [-300, -150, 0, 150, 300], making 5 discharges at each voltage to verify reproducibility.
Apart from intermittence, we will quantify all other turbulence parameters that can be measured by the probes: <math>V_f, I_{\rm sat}, E_r, E_\theta, v_\theta, \Gamma</math>, the RMS of various quantities, long-range correlations between probes B and D, cross phase (between <math>E_\theta, I_{\rm sat}</math>), etc.<ref>B. van Milligen, B. Carreras, I. Voldiner, U. Losada, C. Hidalgo, and the TJ-II Team. ''Causality, intermittence and crossphase evolution during confinement transitions in the TJ-II stellarator''. Phys. Plasmas, 28:092302, 2021.</ref>

== International or National funding project or entity ==
Ministerio de Ciencia, Innovación y Universidades Nº PGC2018-097279-B-I00

== Description of required resources ==
Required resources:
* Dynamic iota scan between configurations 100_40 and 100_44
* Biasing at fixed voltage [-300, -150, 0, 150, 300]
* Number of plasma discharges or days of operation: 30 discharges, 1 day
* Essential diagnostic systems: Langmuir probes
* Desirable diagnostic systems: Doppler reflectometer, HIBP (at similar radial positions as the Langmuir probes)
* Type of plasmas (heating configuration): ECRH heated, density constant, below critical density (<math>n_e \simeq 0.6\cdot 10^{19} {\mathrm m}^{-3}</math>)

== Preferred dates and degree of flexibility ==
Preferred dates: N/A


== References ==
<references />

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