FusionWiki - User contributions [en]

LNF:Organization

2023-02-01T15:51:53Z

Sanedi: /* Fusion Theory Unit */

== Laboratorio Nacional de Fusión ==

Asociación [[Euratom]]-[[CIEMAT]]: see [[Laboratorio Nacional de Fusión]].

Contact information is also available via the [http://www.ciemat.es/cargarFichaOrganizacion.do?idOrganizacion=F00 CIEMAT website]

The telephone numbers listed below are extensions; to call from outside the laboratory, dial: +34-91346xxxx, where xxxx is the extension. (When using 4-digit dialing from inside the laboratory: substitute any initial "0" by a "7".)

[https://www.gruptelecom.com/wp-content/uploads/2018/07/Manual_Unify_CP-200.pdf IP-phone manual]

{|class="wikitable" style="vertical-align:top;"||
|-
!Name!!Telephone (old)!!IP-phone
|-
| Hidalgo Vera, Carlos, Director || 6498 ||
|-
| Guerard Ortego, Carlos Kjell || - ||
|-
|}

=== TJ-II Experimental Division ===

{|class="wikitable" style="vertical-align:top;"||
|-
!Name!!Telephone (old)!!IP-phone
|-
| Alonso de Pablo, Arturo || +49 3834 88 2342 ||
|-
| Baciero Adrados, Alfonso || 6493 || 362601
|-
| Blanco Villareal, Emilio J. || 7904 ||
|-
| de la Cal Heusch, Eduardo || 6317 ||
|-
| Carralero Ortiz, Daniel || 7852 ||
|-
| Castro Rojo, Rodrigo || 6419 ||
|-
| Estrada García, Mª. Teresa || 0845 ||
|-
| Fontdecaba Climent, Jose María || 6642 ||
|-
| García Cortés, Mª. Isabel || 6515 || 362625
|-
| Hernanz Hernanz, Francisco J. || 6641 ||
|-
| López Miranda, Belén || || 362093
|-
| McCarthy, Kieran Joseph || 0846 || 362934
|-
| Medina Yela, Francisco || 0847 || 362935
|-
| Ochando Garcia, Mª. Antonia || 6462 ||
|-
| de Pablos Hernández, Jose Luis || 6374 ||
|-
| Panadero Álvarez, Nerea || 6642 || 362781
|-
| Pastor Díaz, Ignacio || 6324 ||
|-
| Pastor Santos, Carmen || || 362564
|-
| Rattá Gutiérrez, Giuseppe A. || 7917 ||
|-
| Rodríguez Fernández, Mª. Carmen || 2611 ||
|-
| [[User:Admin|van Milligen, Boudewijn]] || 6379 || 362482
|-
| Vega Sánchez, Jesús Antonio || 6474 ||
|}

=== TJ-II Operation Division===

{|class="wikitable" style="vertical-align:top;"||
|-
!Name!!Telephone (old)!!IP-phone
|-
| Ascasíbar, Enrique, Head Investigator || 6369 ||
|-
| Alegre Castro, Daniel || 0914 ||
|-
| Cappa Ascasíbar, Alvaro || 6646 Sala de Control ECRH 6828 ||
|-
| Cebrián Ruiz, Luis A. || 6338 ||
|-
| Chamorro Lastra, Manuel || 6641 ||
|-
| García Gomez, Raúl || 6641 ||
|-
| Guasp Pérez, Jose || 6510 ||
|-
| Guisse Arévalo, Víctor H. || 6285 ||
|-
| Liniers Vazquez, Macarena || 0844 Sala de Control NBI 6851 ||
|-
| Martín Diaz, Fernando || 0920 Sala de Control NBI 6851 ||
|-
| Martinez Fernandez, Jose || 6646 Sala de Control ECRH 6828 ||
|-
| Bueno Jañez, Luis Alberto || 6285 ||
|-
| Miguel Honrubia, Francisco J. || 6762 ||
|-
| Navarro Santana Miguel || 6824 ||
|-
| Pereira Gonzalez, Augusto || 0929 ||
|-
| Portas Ferreiro, Ana Belén || 0929 ||
|-
| Ros Vivancos, Alfonso || 6642 Sala de Control ECRH 6828 Lab. μOndas 6808 || 362782
|-
| Sánchez Sarabia, Emilio || 6762 ||
|-
| Sebastián Alfaro, José Antonio || 6684 Sala de Control NBI 6851 || 362828
|-
| Tabarés Vazquez, Francisco Luis || 6458 ||
|-
| Tafalla García, David || 0843 ||
|-
| Tolkachev, Alexander || 6828 ||
|}

=== Fusion Theory Unit ===

{|class="wikitable" style="vertical-align:top;"||
|-
!Name!!Telephone (old)!!IP-phone
|-
| Calvo Rubio, Iván, Head Investigator || 6739 || 362872
|-
| Escoto López, Francisco Javier || ||
|-
| García Regaña, José Manuel || 7850 || 362938
|-
| Godino Sedano, Guillermo Luis || 7920 || 362780
|-
| González Jerez, Antonio || 7916 ||
|-
| López Bruna, Daniel || 6638 ||
|-
| [[User:Esolano|Solano (Rodríguez-Solano Ribeiro), Emilia R.]]|| 6153 ||
|-
| Sánchez González, Edilberto || 6162 || 362264
|-
| Thienpondt, Hanne || ||
|-
| Velasco Garasa, José Luis || 6504 || 362610
|}

=== Engineering Unit ===

{|class="wikitable" style="vertical-align:top;"||
|-
!Name!!Telephone (old)!!IP-phone
|-
| Alonso, José Javier, Head Investigator || 6639 ||
|-
| Cabrera Pérez, Santiago || || 362994
|-
| Carrasco García, Ricardo || 7928 ||
|-
| Fernández Navarro, Alejandro || 6637 || 362771
|-
| Jimenez Denche, Andrés Enrique || 6584 ||
|-
| Kirpitchev, Igor || 6337 ||
|-
| Lapayese Puebla, Fernando || 0928 ||
|-
| Medrano Casanova, Mercedes || 6639 ||
|-
| Méndez Montero, Purificación || 6337 ||
|-
| de la Peña Gómez, Ángel || 6644 ||
|-
| Queral Mas, Vicente || 6419 || 362518
|-
| Ramos Rivero, Francisco || 6584 ||
|-
| Rincón Rincón, María Esther || 6637 ||
|-
| Soleto Palomo, M. Alfonso || 6636 ||
|-
| Weber Suárez, Moisés || 6636 ||
|}

=== Technology Division ===

{|class="wikitable" style="vertical-align:top;"||
|-
!Name!!Telephone (old)!!IP-phone
|-
| Rapisarda Socorro, David, Head Investigator || 0913/6335 (prov) || 362998
|-
| Brañas Lasala, Beatriz || 6289 ||
|-
| Carella, Elisabetta || 6507 ||
|-
| Fernández Berceruelo, Iván || 2579 ||
|-
| García Gonzalez, Juan Manuel || 7842 ||
|-
| Garcinuño Pindado, Belit || 6584 || 362717
|-
| Gonzalez Viada, María || 2582 ||
|-
| Gutierrez Pérez, Víctor || 6307 || 362413
|-
| Hernandez Diaz, Mª. Teresa || 2581 ||
|-
| Herranz Marco, Jesús Antonio || 0848 ||
|-
| Jimenez Baena, Francisco M. || 6204 ||
|-
| Jiménez Rey, David || 6640 ||
|-
| Malo Huerta, Marta || 6636 || 362769
|-
| Martín Laso, Montserrat || 6512 ||
|-
| Molla Lorente, Joaquín || 6580 ||
|-
| de la Morena Álvarez-Palencia, Cristina || 2600 ||
|-
| Moroño Guadalajara, Alejandro A. || 6372 ||
|-
| Mota García, Fernando || 6578 || 362708
|-
| Navas, Julia || || 362428
|-
| Ortíz, Christophe || 2582 ||
|-
| Palermo, Iole || 6784 ||
|-
| Patiño, Julian || || 362428
|-
| Regidor Serrano, David || 6584 ||
|-
| Roldán Blanco, Marcelo || 2574 Lab. 6512 ||
|-
| Román Chacón, Raquel || 6203 ||
|-
| Sánchez Sanz, Fernando José || 6578 FIB-SEM 6790 ||
|-
| Valle Paisan, Francisco J. || 6204 ||
|-
| Vila Vazquez, Rafael Alberto || 6580 ||
|-
| Villamayor Callejo, Víctor || 6578 ||
|-
|}

=== Support Unit ===

{|class="wikitable" style="vertical-align:top;"||
|-
!Name!!Telephone (old)!!IP-phone
|-
| Barrera Orte, Laura || || 362262
|-
| Fernandez-Mayoralas López, Lorena || 6663 ||
|-
| Moreno García, Sabina || 6159 ||
|-
| Sánchez Rubio, Cristina || 6738 ||
|}

EUTERPE

2022-06-28T07:20:37Z

Sanedi:

The EUTERPE gyrokinetic code was created at the CRPP in Lausanne as a global linear particle in cell code for studying electrostatic plasma instabilities <ref>G. Jost, T. M. Tran, K. Appert, W. A. Cooper, and L. Villard, [http://www.ispp.it/Courses_and_Workshops.html in Theory of Fusion Plasmas, International Workshop, Varenna, September 1998 (Editrice Compositori, Società Italiana di Fisica, Bologna, 1999), p. 419.]</ref>. It allows three-dimensional turbulence simulations using a plasma equilibrium calculated with the [[VMEC]] code as a starting point. EUTERPE was further developed at the Max Planck IPP and several linear calculations of ion temperature gradient (ITG) driven turbulence in [[Tokamak|tokamak]] and [[Stellarator|stellarator]] geometry have been carried out using it
<ref>G. Jost, T. M. Tran, W. Cooper, and K. Appert. [[doi:10.1063/1.1374585|Phys. Plasmas '''8''': 3321 (2001)]]</ref>
<ref>V. Kornilov, R. Kleiber, R. Hatzky, L. Villard, and G. Jost. [[doi:10.1063/1.1737393|Phys. Plasmas '''11''': 3196 (2004)]]</ref>
<ref>V. Kornilov, R. Kleiber, and R. Hatzky, [[doi:10.1088/0029-5515/45/4/003|Nucl. Fusion '''45''': 238 (2005)]]</ref>
<ref>R. Kleiber, ''Global linear gyrokinetic simulations for stellarator and axisymmetric equilibria'', Joint Varenna-Lausanne International Workshop. [[doi:10.1063/1.2404546|AIP Conference Proceedings, 871, p. 136, 2006]]</ref>
<ref>Particle in cell simulations at the Laboratorio Nacional de Fusión[[http://fusionsites.ciemat.es/picgklnf/]]</ref>.
Afterwards, the code has been heavily optimized and improved. The perturbation to the magnetic field, a third species (in adition to electrons and ions) and the non-linear dynamics have been included.

The EUTERPE code solves the gyroaveraged Vlasov equation for the distribution function of ions

:<math>
\frac{\partial f}{\partial t} + \frac{\rm{d}v_{||}}{\rm{d}t} \frac{\partial f}{\partial v_{||}} + \frac{\rm{d}\vec{R}}{\rm{d}t} \frac{\partial f}{\partial \vec{R}} = 0
</math>

The code is based on the particle-in-cell (PIC) scheme, where the distribution function is discretized using markers. The δf approximation is used, so that the distribution function is decomposed in an equilibrium part (Maxwellian) and a time-dependent perturbation.

:<math>
f(\vec R, v_{||}, \mu, t) = f_{0}(\vec R, v_{||}, v_{\perp})+ \delta f(\vec R, v_{||}, \mu, t)
</math>

Each marker along with its weight is evolved following the particle trayectories and contributes a part to the distribution function, so that

:<math>
\delta f = \sum_{p=1} ^{N} w_p \delta ^{3}(\vec R - \vec R_p)\delta(v_{||} - v_{||p})\delta(\mu - \mu_p) /(2 \pi B),
</math>

where the <math>w_p</math> are the weights (contribution to the distribution function) associated to each marker.

The electric potential is represented on a spatial grid, the electric charge being carried by the markers. Two coordinate systems are used in the code: a system of magnetic coordinates (PEST) <math>(s, \theta,\phi )</math> is used for the electrostatic potential and cylindrical coordinates <math>(r, z,\phi )</math> are used for pushing the particles, where <math>s=\Psi / \Psi_0</math> is the normalized toroidal flux. The change between coordinate systems, which is facilitated by the existence of the common coordinate <math>(\phi)</math>, is done in a continuous way. The equation for the field is discretized using finite elements (B-splines) and the PETSc library is used for solving it. The integration of the motion is done using a fourth order Runge-Kutta scheme. In linear simulations a phase factor transformation can be used and the equations can be integrated using a predictor-corrector scheme.

An equilibrium state calculated with the code VMEC is used as a starting point. The equilibrium quantities computed by VMEC are mapped onto the spatial grid using an intermediate program.

EUTERPE features several techniques for the noise control: the filtering of Fourier modes (square and diagonal filters can be used) and the optimized loading <ref>Hatzky, R Tran, TM Konies, A Kleiber, R Allfrey, SJ .Energy conservation in a nonlinear gyrokinetic particle-in-cell code for ion-temperature-gradient-driven modes in theta-pinch geometry. [[doi:10.1063/1.1449889|Phys. Plasmas, 9- 3, p. 898, 2002.]]</ref>.

==References==
<references />

[[Category:Software]]

EUTERPE

2022-06-28T07:19:32Z

Sanedi:

The EUTERPE gyrokinetic code was created at the CRPP in Lausanne as a global linear particle in cell code for studying electrostatic plasma instabilities <ref>G. Jost, T. M. Tran, K. Appert, W. A. Cooper, and L. Villard, [http://www.ispp.it/Courses_and_Workshops.html in Theory of Fusion Plasmas, International Workshop, Varenna, September 1998 (Editrice Compositori, Società Italiana di Fisica, Bologna, 1999), p. 419.]</ref>. It allows three-dimensional turbulence simulations using a plasma equilibrium calculated with the [[VMEC]] code as a starting point. EUTERPE was further developed at the Max Planck IPP and several linear calculations of ion temperature gradient (ITG) driven turbulence in [[Tokamak|tokamak]] and [[Stellarator|stellarator]] geometry have been carried out using it
<ref>G. Jost, T. M. Tran, W. Cooper, and K. Appert. [[doi:10.1063/1.1374585|Phys. Plasmas '''8''': 3321 (2001)]]</ref>
<ref>V. Kornilov, R. Kleiber, R. Hatzky, L. Villard, and G. Jost. [[doi:10.1063/1.1737393|Phys. Plasmas '''11''': 3196 (2004)]]</ref>
<ref>V. Kornilov, R. Kleiber, and R. Hatzky, [[doi:10.1088/0029-5515/45/4/003|Nucl. Fusion '''45''': 238 (2005)]]</ref>
<ref>R. Kleiber, ''Global linear gyrokinetic simulations for stellarator and axisymmetric equilibria'', Joint Varenna-Lausanne International Workshop. [[doi:10.1063/1.2404546|AIP Conference Proceedings, 871, p. 136, 2006]]</ref>
<ref>[[http://fusionsites.ciemat.es/picgklnf/]]</ref>.
Afterwards, the code has been heavily optimized and improved. The perturbation to the magnetic field, a third species (in adition to electrons and ions) and the non-linear dynamics have been included.

The EUTERPE code solves the gyroaveraged Vlasov equation for the distribution function of ions

:<math>
\frac{\partial f}{\partial t} + \frac{\rm{d}v_{||}}{\rm{d}t} \frac{\partial f}{\partial v_{||}} + \frac{\rm{d}\vec{R}}{\rm{d}t} \frac{\partial f}{\partial \vec{R}} = 0
</math>

The code is based on the particle-in-cell (PIC) scheme, where the distribution function is discretized using markers. The δf approximation is used, so that the distribution function is decomposed in an equilibrium part (Maxwellian) and a time-dependent perturbation.

:<math>
f(\vec R, v_{||}, \mu, t) = f_{0}(\vec R, v_{||}, v_{\perp})+ \delta f(\vec R, v_{||}, \mu, t)
</math>

Each marker along with its weight is evolved following the particle trayectories and contributes a part to the distribution function, so that

:<math>
\delta f = \sum_{p=1} ^{N} w_p \delta ^{3}(\vec R - \vec R_p)\delta(v_{||} - v_{||p})\delta(\mu - \mu_p) /(2 \pi B),
</math>

where the <math>w_p</math> are the weights (contribution to the distribution function) associated to each marker.

The electric potential is represented on a spatial grid, the electric charge being carried by the markers. Two coordinate systems are used in the code: a system of magnetic coordinates (PEST) <math>(s, \theta,\phi )</math> is used for the electrostatic potential and cylindrical coordinates <math>(r, z,\phi )</math> are used for pushing the particles, where <math>s=\Psi / \Psi_0</math> is the normalized toroidal flux. The change between coordinate systems, which is facilitated by the existence of the common coordinate <math>(\phi)</math>, is done in a continuous way. The equation for the field is discretized using finite elements (B-splines) and the PETSc library is used for solving it. The integration of the motion is done using a fourth order Runge-Kutta scheme. In linear simulations a phase factor transformation can be used and the equations can be integrated using a predictor-corrector scheme.

An equilibrium state calculated with the code VMEC is used as a starting point. The equilibrium quantities computed by VMEC are mapped onto the spatial grid using an intermediate program.

EUTERPE features several techniques for the noise control: the filtering of Fourier modes (square and diagonal filters can be used) and the optimized loading <ref>Hatzky, R Tran, TM Konies, A Kleiber, R Allfrey, SJ .Energy conservation in a nonlinear gyrokinetic particle-in-cell code for ion-temperature-gradient-driven modes in theta-pinch geometry. [[doi:10.1063/1.1449889|Phys. Plasmas, 9- 3, p. 898, 2002.]]</ref>.

==References==
<references />

[[Category:Software]]

TJ-II:Comparison of transport of on-axis and off-axis ECH-heated plasmas

2017-01-27T12:29:06Z

Sanedi: /* Description of required resources */

== Experimental campaign ==
2017 Spring

== Proposal title ==
''Comparison of transport of on-axis and off-axis ECH-heated plasmas''

== Name and affiliation of proponent ==
José Luis Velasco, Edi Sánchez, Teresa Estrada, Álvaro Cappa, the HIBP team et al.

== Details of contact person at LNF (if applicable) ==

== Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)==
'''Motivation.'''

Particle transport of ECH plasmas<ref>Yokoyama 2005 NF</ref> is not well understood, as neoclassical simulations seem to overestimate the radial particle flux of on-axis heated ECH-plasmas; on the other hand, preliminary analyses show that this problem does not exist for off-axis ECH-heated plasmas. A comparison between these two situations (including neoclassical and gyrokinetic simulations and corresponding measurements) may shed some light on this problem, probably relevant for assessing the fuelling requirements of reactor plasmas<ref>Maassberg 1999 NF</ref>. Even if the results along this line are finally not conclusive, the experimental and theoretical characterization of turbulence with different profiles (peaked/hollow <math>T_e</math> with hollow/peaked <math>n_e</math>) is itself relevant. We will also have a look at impurity transport, as off-axis heated plasmas have been predicted to have negative radial electric field in the core and positive radial electric field closer to the edge, contrary to typical ECH plasmas.

'''Objectives.'''

In this experiment we plan to scan (shot-to-shot) the radial position of ECH absortion and measure:

* Electron density and temperature profile.
* Radial electric field profile.
* ....

We will compare the measurements with neoclassical and gyrokinetic simulations.

== If applicable, International or National funding project or entity ==
EUROfusion WP17.S1.A2, WP17.S1.A3, WP17.S2.1.8,ENE2015-70142-P

== Description of required resources ==
Required resources:
* Number of plasma discharges or days of operation: 1 day.
* Essential diagnostic systems:
We will measure:

- The time evolution of the line-averaged density <math><n_e(t)></math> with interferometry.

- The radial profiles of electron density <math>n_e(r,t_0)</math> and temperature <math>T_e(r,t_0)</math> at one time instant <math>t_0</math> with Thomson Scattering (TS) and the He beam.

- The time evolution of the electron temperature profile <math>T_e(r,t)</math> with Electron Cyclotron Emission (ECE), when available, calibrated with TS.

- The time evolution of the ion temperature in the core and in an outer radial position, <math>T_i(r/a=0.2,t)</math> and <math>T_i(r/a~=0.6,t)</math>, with the Neutral Particle Analyzer (NPA).

- The time evolution of the radial electric field in the gradient region <math>E_r(r/a~=0.65,t)</math>, with reflectometry.

- The profiles of the electrostatic potential.

- ...

* Type of plasmas (heating configuration): ECH plasmas with constant line-averaged density. From previous experiments, we have on-axis heated plasmas, and plasmas with one gyrotron on-axis and the other off-axis, so we will focus in totally off-axis heating.
* Specific requirements on wall conditioning if any: recent lithium-coating for good density control.
* External users: need a local computer account for data access: yes/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 />

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

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

TJ-II:Excitation of zonal flow oscillations by energetic particles

2017-01-25T12:30:02Z

Sanedi: /* Description of required resources */

== Experimental campaign ==
2017 Spring

== Proposal title ==
'''Excitation of zonal flow oscillations by energetic particles'''

== Name and affiliation of proponent ==
Edilberto Sánchez, José Luis Velasco, Iván Calvo, José Manuel García-Regaña

== Details of contact person at LNF (if applicable) ==
Edilberto Sánchez (edi.sanchez@ciemat.es)

== Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)==

'''Motivation'''

In stellarators the zonal flows (ZF) undergo several oscillations depending on the magnetic geometry and the plasma conditions. First, a Geodesic Acoustic Mode (GAM) oscillation, similar to that in tokamaks, appears, whose collisionless damping strongly depends on the rotational transform. A new oscillation, at a lower frequency, recently discovered theoretically <ref>Mishchenko PoP 2008</ref>, appears in stelallarators that is not present in quasisymmetric devices. In TJ-II, both oscillations have been found in simulations <ref>Sánchez PPCF 2013</ref> and the low frequency one has been identified for the first time during pellet injection experiments <ref>Alonso PRL 2017</ref>. Other experimental evidences appear to be related to zonal flow oscillations, both low frequency <ref>Pedrosa PoP 2008</ref> and GAM <ref>Castejón PPCF 2016</ref>.

According to gyrokinetic simulations, the GAM and LFO oscillations are damped in the TJ-II geometry (even collisionlessly) and the necessary driving mechanism has not been identified so far. The turbulence can drive (non-linearly) these oscillations, but it is not the only option as driving mechanism.
In tokamaks it has been found that energetic particles can drive the GAM oscillation (EGAMs) <ref>Zarzoso PRL 2013 and reference therein</ref>, but in stellarators there are less evidences <ref>Sun EFL 2016</ref> and the oscillation fauna is wider than in tokamaks.

'''Objectives'''

In this experiment we plan to study the excitation of ZF oscillations by energetic particles in TJ-II.

We will work in NBI plasmas and will look for LFO by means of the Doppler reflectometry system and the dual HIBP. We will change the energy and intensity of the neutral beam in order to identify changes in the LFO, that can be reproduced in GK simulations, if these oscillations are generated.

As an alternative we could work in ECRH heated plasmas and generate fast ions by means of the diagnostic neutral beam injector (DNBI) and try to measure oscillations in the zonal potential, if we are able to generate them. If so, we will characterize their spectrum and study the dependency with parameters: beam intensity, beam energy, and ion and electron temperatures.

The experimental results will be compared to dedicated gyrokinetic simulations.

== If applicable, International or National funding project or entity ==
N/A

== Description of required resources ==

The experiments will be carried out in ECRH plasmas that will provide a ground state to add the fast ions from the neutral beam. At this stage, no change in the magnetic configuraton is required. We will work in the standard 100_44_64.

A basic characterization of the plasmas will require the interferometer and Thomson Scattering diagnostics.
A good estimation of experimental electron density and temperature profiles at times of interest will be required for the simulations. In addition to the Thomson measurements, the He beam will help in fitting the profiles in the plasma edge and the NPA will be required to have some information about the ion temperature.
The Doppler reflectometer and the dual HIBP are basic for the characterization of the potential oscillations.

A characterization of the fast ions populations by means of the CNPA and passive spectrroscopy and/or luminiscent probes will be very convenient.

Required resources:
* Number of plasma discharges or days of operation: one experimental day.
* Essential diagnostic systems:

- Interferometry
- Thomson Scattering
- Neutral Particle Analyzer
- Helium beam
- The double Heavy Ion Beam probe
- Doppler reflectometer
- [ CNPA - passive spectrroscopy and/or luminiscent probes]

* Type of plasmas (heating configuration): stable NBI (and/or ECRH) plasmas in the standard configuration.
* Specific requirements on wall conditioning if any:
* 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 />

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

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

TJ-II:Excitation of zonal flow oscillations by energetic particles

2017-01-25T12:29:14Z

Sanedi: /* Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages) */

== Experimental campaign ==
2017 Spring

== Proposal title ==
'''Excitation of zonal flow oscillations by energetic particles'''

== Name and affiliation of proponent ==
Edilberto Sánchez, José Luis Velasco, Iván Calvo, José Manuel García-Regaña

== Details of contact person at LNF (if applicable) ==
Edilberto Sánchez (edi.sanchez@ciemat.es)

== Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)==

'''Motivation'''

In stellarators the zonal flows (ZF) undergo several oscillations depending on the magnetic geometry and the plasma conditions. First, a Geodesic Acoustic Mode (GAM) oscillation, similar to that in tokamaks, appears, whose collisionless damping strongly depends on the rotational transform. A new oscillation, at a lower frequency, recently discovered theoretically <ref>Mishchenko PoP 2008</ref>, appears in stelallarators that is not present in quasisymmetric devices. In TJ-II, both oscillations have been found in simulations <ref>Sánchez PPCF 2013</ref> and the low frequency one has been identified for the first time during pellet injection experiments <ref>Alonso PRL 2017</ref>. Other experimental evidences appear to be related to zonal flow oscillations, both low frequency <ref>Pedrosa PoP 2008</ref> and GAM <ref>Castejón PPCF 2016</ref>.

According to gyrokinetic simulations, the GAM and LFO oscillations are damped in the TJ-II geometry (even collisionlessly) and the necessary driving mechanism has not been identified so far. The turbulence can drive (non-linearly) these oscillations, but it is not the only option as driving mechanism.
In tokamaks it has been found that energetic particles can drive the GAM oscillation (EGAMs) <ref>Zarzoso PRL 2013 and reference therein</ref>, but in stellarators there are less evidences <ref>Sun EFL 2016</ref> and the oscillation fauna is wider than in tokamaks.

'''Objectives'''

In this experiment we plan to study the excitation of ZF oscillations by energetic particles in TJ-II.

We will work in NBI plasmas and will look for LFO by means of the Doppler reflectometry system and the dual HIBP. We will change the energy and intensity of the neutral beam in order to identify changes in the LFO, that can be reproduced in GK simulations, if these oscillations are generated.

As an alternative we could work in ECRH heated plasmas and generate fast ions by means of the diagnostic neutral beam injector (DNBI) and try to measure oscillations in the zonal potential, if we are able to generate them. If so, we will characterize their spectrum and study the dependency with parameters: beam intensity, beam energy, and ion and electron temperatures.

The experimental results will be compared to dedicated gyrokinetic simulations.

== If applicable, International or National funding project or entity ==
N/A

== Description of required resources ==

The experiments will be carried out in ECRH plasmas that will provide a ground state to add the fast ions from the neutral beam. At this stage, no change in the magnetic configuraton is required. We will work in the standard 100_44_64.

A basic characterization of the plasmas will require the interferometer and Thomson Scattering diagnostics.
A good estimation of experimental electron density and temperature profiles at times of interest will be required for the simulations. In addition to the Thomson measurements, the He beam will help in fitting the profiles in the plasma edge and the NPA will be required to have some information about the ion temperature.
The Doppler reflectometer and the dual HIBP are basic for the characterization of the potential oscillations.

A characterization of the fast ions populations by means of the CNPA and passive spectrroscopy and/or luminiscent probes will be very convenient.

Required resources:
* Number of plasma discharges or days of operation: one experimental day.
* Essential diagnostic systems:

- Interferometry
- Thomson Scattering
- Neutral Particle Analyzer
- Helium beam
- The double Heavy Ion Beam probe
- Doppler reflectometer
- [ CNPA - passive spectrroscopy and/or luminiscent probes]

* Type of plasmas (heating configuration): stable ECRH plasmas in the standard configuration.
* Specific requirements on wall conditioning if any:
* 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 />

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

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

TJ-II:Excitation of zonal flow oscillations by energetic particles

2017-01-25T12:22:21Z

Sanedi: /* Description of required resources */

== Experimental campaign ==
2017 Spring

== Proposal title ==
'''Excitation of zonal flow oscillations by energetic particles'''

== Name and affiliation of proponent ==
Edilberto Sánchez, José Luis Velasco, Iván Calvo, José Manuel García-Regaña

== Details of contact person at LNF (if applicable) ==
Edilberto Sánchez (edi.sanchez@ciemat.es)

== Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)==

'''Motivation'''

In stellarators the zonal flows (ZF) undergo several oscillations depending on the magnetic geometry and the plasma conditions. First, a Geodesic Acoustic Mode (GAM) oscillation, similar to that in tokamaks, appears, whose collisionless damping strongly depends on the rotational transform. A new oscillation, at a lower frequency, recently discovered theoretically <ref>Mishchenko PoP 2008</ref>, appears in stelallarators that is not present in quasisymmetric devices. In TJ-II, both oscillations have been found in simulations <ref>Sánchez PPCF 2013</ref> and the low frequency one has been identified for the first time during pellet injection experiments <ref>Alonso PRL 2017</ref>. Other experimental evidences appear to be related to zonal flow oscillations, both low frequency <ref>Pedrosa PoP 2008</ref> and GAM <ref>Castejón PPCF 2016</ref>.

According to gyrokinetic simulations, the GAM and LFO oscillations are damped in the TJ-II geometry (even collisionlessly) and the necessary driving mechanism has not been identified so far. The turbulence can drive (non-linearly) these oscillations, but it is not the only option as driving mechanism.
In tokamaks it has been found that energetic particles can drive the GAM oscillation (EGAMs) <ref>Zarzoso PRL 2013 and reference therein</ref>, but in stellarators there are less evidences <ref>Sun EFL 2016</ref> and the oscillation fauna is wider than in tokamaks.

'''Objectives'''

In this experiment we plan to study the excitation of ZF oscillations by energetic particles in TJ-II.

We will generate fast ions by means of the diagnostic neutral beam injector and try to measure oscillations in the zonal potential, if we are able to generate them. If so, we will characterize their spectrum and study the dependency with parameters: beam intensity, beam energy, and ion and electron temperatures.

The experimental results will be compared to dedicated gyrokinetic simulations.

== If applicable, International or National funding project or entity ==
N/A

== Description of required resources ==

The experiments will be carried out in ECRH plasmas that will provide a ground state to add the fast ions from the neutral beam. At this stage, no change in the magnetic configuraton is required. We will work in the standard 100_44_64.

A basic characterization of the plasmas will require the interferometer and Thomson Scattering diagnostics.
A good estimation of experimental electron density and temperature profiles at times of interest will be required for the simulations. In addition to the Thomson measurements, the He beam will help in fitting the profiles in the plasma edge and the NPA will be required to have some information about the ion temperature.
The Doppler reflectometer and the dual HIBP are basic for the characterization of the potential oscillations.

A characterization of the fast ions populations by means of the CNPA and passive spectrroscopy and/or luminiscent probes will be very convenient.

Required resources:
* Number of plasma discharges or days of operation: one experimental day.
* Essential diagnostic systems:

- Interferometry
- Thomson Scattering
- Neutral Particle Analyzer
- Helium beam
- The double Heavy Ion Beam probe
- Doppler reflectometer
- [ CNPA - passive spectrroscopy and/or luminiscent probes]

* Type of plasmas (heating configuration): stable ECRH plasmas in the standard configuration.
* Specific requirements on wall conditioning if any:
* 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 />

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

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

TJ-II:Excitation of zonal flow oscillations by energetic particles

2017-01-25T12:21:09Z

Sanedi: /* Description of required resources */

== Experimental campaign ==
2017 Spring

== Proposal title ==
'''Excitation of zonal flow oscillations by energetic particles'''

== Name and affiliation of proponent ==
Edilberto Sánchez, José Luis Velasco, Iván Calvo, José Manuel García-Regaña

== Details of contact person at LNF (if applicable) ==
Edilberto Sánchez (edi.sanchez@ciemat.es)

== Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)==

'''Motivation'''

In stellarators the zonal flows (ZF) undergo several oscillations depending on the magnetic geometry and the plasma conditions. First, a Geodesic Acoustic Mode (GAM) oscillation, similar to that in tokamaks, appears, whose collisionless damping strongly depends on the rotational transform. A new oscillation, at a lower frequency, recently discovered theoretically <ref>Mishchenko PoP 2008</ref>, appears in stelallarators that is not present in quasisymmetric devices. In TJ-II, both oscillations have been found in simulations <ref>Sánchez PPCF 2013</ref> and the low frequency one has been identified for the first time during pellet injection experiments <ref>Alonso PRL 2017</ref>. Other experimental evidences appear to be related to zonal flow oscillations, both low frequency <ref>Pedrosa PoP 2008</ref> and GAM <ref>Castejón PPCF 2016</ref>.

According to gyrokinetic simulations, the GAM and LFO oscillations are damped in the TJ-II geometry (even collisionlessly) and the necessary driving mechanism has not been identified so far. The turbulence can drive (non-linearly) these oscillations, but it is not the only option as driving mechanism.
In tokamaks it has been found that energetic particles can drive the GAM oscillation (EGAMs) <ref>Zarzoso PRL 2013 and reference therein</ref>, but in stellarators there are less evidences <ref>Sun EFL 2016</ref> and the oscillation fauna is wider than in tokamaks.

'''Objectives'''

In this experiment we plan to study the excitation of ZF oscillations by energetic particles in TJ-II.

We will generate fast ions by means of the diagnostic neutral beam injector and try to measure oscillations in the zonal potential, if we are able to generate them. If so, we will characterize their spectrum and study the dependency with parameters: beam intensity, beam energy, and ion and electron temperatures.

The experimental results will be compared to dedicated gyrokinetic simulations.

== If applicable, International or National funding project or entity ==
N/A

== Description of required resources ==

The experiments will be carried out in ECRH plasmas that will provide a ground state to add the fast ions from the neutral beam. At this stage, no change in the magnetic configuraton is required. We will work in the standard 100_44_64.

A basic characterization of the plasmas will require the interferometer and Thomson Scattering diagnostics.
A good estimation of experimental electron density and temperature profiles at times of interest will be required for the simulations. In addition to the Thomson measurements, the He beam will help in fitting the profiles in the plasma edge and the NPA will be required to have some information about the ion temperature.
The Doppler reflectometer and the dual HIBP are basic for the characterization of the potential oscillations.

A characterization of the fast ions populations by means of passive spectrroscopy and/or luminiscent probes will be very convenient.

Required resources:
* Number of plasma discharges or days of operation: one experimental day.
* Essential diagnostic systems:

- Interferometry
- Thomson Scattering
- Neutral Particle Analyzer
- Helium beam
- The double Heavy Ion Beam probe
- Doppler reflectometer
- [ CNPA - passive spectrroscopy and/or luminiscent probes]

* Type of plasmas (heating configuration): stable ECRH plasmas in the standard configuration.
* Specific requirements on wall conditioning if any:
* 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 />

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

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

TJ-II:Excitation of zonal flow oscillations by energetic particles

2017-01-25T12:20:51Z

Sanedi: /* Description of required resources */

== Experimental campaign ==
2017 Spring

== Proposal title ==
'''Excitation of zonal flow oscillations by energetic particles'''

== Name and affiliation of proponent ==
Edilberto Sánchez, José Luis Velasco, Iván Calvo, José Manuel García-Regaña

== Details of contact person at LNF (if applicable) ==
Edilberto Sánchez (edi.sanchez@ciemat.es)

== Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)==

'''Motivation'''

In stellarators the zonal flows (ZF) undergo several oscillations depending on the magnetic geometry and the plasma conditions. First, a Geodesic Acoustic Mode (GAM) oscillation, similar to that in tokamaks, appears, whose collisionless damping strongly depends on the rotational transform. A new oscillation, at a lower frequency, recently discovered theoretically <ref>Mishchenko PoP 2008</ref>, appears in stelallarators that is not present in quasisymmetric devices. In TJ-II, both oscillations have been found in simulations <ref>Sánchez PPCF 2013</ref> and the low frequency one has been identified for the first time during pellet injection experiments <ref>Alonso PRL 2017</ref>. Other experimental evidences appear to be related to zonal flow oscillations, both low frequency <ref>Pedrosa PoP 2008</ref> and GAM <ref>Castejón PPCF 2016</ref>.

According to gyrokinetic simulations, the GAM and LFO oscillations are damped in the TJ-II geometry (even collisionlessly) and the necessary driving mechanism has not been identified so far. The turbulence can drive (non-linearly) these oscillations, but it is not the only option as driving mechanism.
In tokamaks it has been found that energetic particles can drive the GAM oscillation (EGAMs) <ref>Zarzoso PRL 2013 and reference therein</ref>, but in stellarators there are less evidences <ref>Sun EFL 2016</ref> and the oscillation fauna is wider than in tokamaks.

'''Objectives'''

In this experiment we plan to study the excitation of ZF oscillations by energetic particles in TJ-II.

We will generate fast ions by means of the diagnostic neutral beam injector and try to measure oscillations in the zonal potential, if we are able to generate them. If so, we will characterize their spectrum and study the dependency with parameters: beam intensity, beam energy, and ion and electron temperatures.

The experimental results will be compared to dedicated gyrokinetic simulations.

== If applicable, International or National funding project or entity ==
N/A

== Description of required resources ==

The experiments will be carried out in ECRH plasmas that will provide a ground state to add the fast ions from the neutral beam. At this stage, no change in the magnetic configuraton is required. We will work in the standard 100_44_64.

A basic characterization of the plasmas will require the interferometer and Thomson Scattering diagnostics.
A good estimation of experimental electron density and temperature profiles at times of interest will be required for the simulations. In addition to the Thomson measurements, the He beam will help in fitting the profiles in the plasma edge and the NPA will be required to have some information about the ion temperature.
The Doppler reflectometer and the dual HIBP are basic for the characterization of the potential oscillations.

A characterization of the fast ions populations by means of passive spectrroscopy and/or luminiscent probes will be very convenient.

Required resources:
* Number of plasma discharges or days of operation: one experimental day.
* Essential diagnostic systems:

- Interferometry
- Thomson Scattering
- Neutral Particle Analyzer
- Helium beam
- The double Heavy Ion Beam probe
- Doppler reflectometer
[- CNPA - passive spectrroscopy and/or luminiscent probes]

* Type of plasmas (heating configuration): stable ECRH plasmas in the standard configuration.
* Specific requirements on wall conditioning if any:
* 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 />

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

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

TJ-II:Excitation of zonal flow oscillations by energetic particles

2017-01-25T09:30:10Z

Sanedi: /* Name and affiliation of proponent */

== Experimental campaign ==
2017 Spring

== Proposal title ==
'''Excitation of zonal flow oscillations by energetic particles'''

== Name and affiliation of proponent ==
Edilberto Sánchez, José Luis Velasco, Iván Calvo, José Manuel García-Regaña

== Details of contact person at LNF (if applicable) ==
Edilberto Sánchez (edi.sanchez@ciemat.es)

== Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)==

'''Motivation'''

In stellarators the zonal flows (ZF) undergo several oscillations depending on the magnetic geometry and the plasma conditions. First, a Geodesic Acoustic Mode (GAM) oscillation, similar to that in tokamaks, appears, whose collisionless damping strongly depends on the rotational transform. A new oscillation, at a lower frequency, recently discovered theoretically <ref>Mishchenko PoP 2008</ref>, appears in stelallarators that is not present in quasisymmetric devices. In TJ-II, both oscillations have been found in simulations <ref>Sánchez PPCF 2013</ref> and the low frequency one has been identified for the first time during pellet injection experiments <ref>Alonso PRL 2017</ref>. Other experimental evidences appear to be related to zonal flow oscillations, both low frequency <ref>Pedrosa PoP 2008</ref> and GAM <ref>Castejón PPCF 2016</ref>.

According to gyrokinetic simulations, the GAM and LFO oscillations are damped in the TJ-II geometry (even collisionlessly) and the necessary driving mechanism has not been identified so far. The turbulence can drive (non-linearly) these oscillations, but it is not the only option as driving mechanism.
In tokamaks it has been found that energetic particles can drive the GAM oscillation (EGAMs) <ref>Zarzoso PRL 2013 and reference therein</ref>, but in stellarators there are less evidences <ref>Sun EFL 2016</ref> and the oscillation fauna is wider than in tokamaks.

'''Objectives'''

In this experiment we plan to study the excitation of ZF oscillations by energetic particles in TJ-II.

We will generate fast ions by means of the diagnostic neutral beam injector and try to measure oscillations in the zonal potential, if we are able to generate them. If so, we will characterize their spectrum and study the dependency with parameters: beam intensity, beam energy, and ion and electron temperatures.

The experimental results will be compared to dedicated gyrokinetic simulations.

== If applicable, International or National funding project or entity ==
N/A

== Description of required resources ==

The experiments will be carried out in ECRH plasmas that will provide a ground state to add the fast ions from the neutral beam. At this stage, no change in the magnetic configuraton is required. We will work in the standard 100_44_64.

A basic characterization of the plasmas will require the interferometer and Thomson Scattering diagnostics.
A good estimation of experimental electron density and temperature profiles at times of interest will be required for the simulations. In addition to the Thomson measurements, the He beam will help in fitting the profiles in the plasma edge and the NPA will be required to have some information about the ion temperature.
The Doppler reflectometer and the dual HIBP are basic for the characterization of the potential oscillations.

A characterization of the fast ions populations by means of passive spectrroscopy and/or luminiscent probes will be very convenient.

Required resources:
* Number of plasma discharges or days of operation: one experimental day.
* Essential diagnostic systems:

- Interferometry
- Thomson Scattering
- Neutral Particle Analyzer
- Helium beam
- The double Heavy Ion Beam probe
- Doppler reflectometer
- [passive spectrroscopy and/or luminiscent probes]

* Type of plasmas (heating configuration): stable ECRH plasmas in the standard configuration.
* Specific requirements on wall conditioning if any:
* 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 />

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

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

TJ-II:Excitation of zonal flow oscillations by energetic particles

2017-01-25T09:15:05Z

Sanedi: /* Details of contact person at LNF (if applicable) */

== Experimental campaign ==
2017 Spring

== Proposal title ==
'''Excitation of zonal flow oscillations by energetic particles'''

== Name and affiliation of proponent ==
Edilberto Sánchez, José Luis Velasco, Kieran McCarthy, Iván Calvo

== Details of contact person at LNF (if applicable) ==
Edilberto Sánchez (edi.sanchez@ciemat.es)

== Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)==

'''Motivation'''

In stellarators the zonal flows (ZF) undergo several oscillations depending on the magnetic geometry and the plasma conditions. First, a Geodesic Acoustic Mode (GAM) oscillation, similar to that in tokamaks, appears, whose collisionless damping strongly depends on the rotational transform. A new oscillation, at a lower frequency, recently discovered theoretically <ref>Mishchenko PoP 2008</ref>, appears in stelallarators that is not present in quasisymmetric devices. In TJ-II, both oscillations have been found in simulations <ref>Sánchez PPCF 2013</ref> and the low frequency one has been identified for the first time during pellet injection experiments <ref>Alonso PRL 2017</ref>. Other experimental evidences appear to be related to zonal flow oscillations, both low frequency <ref>Pedrosa PoP 2008</ref> and GAM <ref>Castejón PPCF 2016</ref>.

According to gyrokinetic simulations, the GAM and LFO oscillations are damped in the TJ-II geometry (even collisionlessly) and the necessary driving mechanism has not been identified so far. The turbulence can drive (non-linearly) these oscillations, but it is not the only option as driving mechanism.
In tokamaks it has been found that energetic particles can drive the GAM oscillation (EGAMs) <ref>Zarzoso PRL 2013 and reference therein</ref>, but in stellarators there are less evidences <ref>Sun EFL 2016</ref> and the oscillation fauna is wider than in tokamaks.

'''Objectives'''

In this experiment we plan to study the excitation of ZF oscillations by energetic particles in TJ-II.

We will generate fast ions by means of the diagnostic neutral beam injector and try to measure oscillations in the zonal potential, if we are able to generate them. If so, we will characterize their spectrum and study the dependency with parameters: beam intensity, beam energy, and ion and electron temperatures.

The experimental results will be compared to dedicated gyrokinetic simulations.

== If applicable, International or National funding project or entity ==
N/A

== Description of required resources ==

The experiments will be carried out in ECRH plasmas that will provide a ground state to add the fast ions from the neutral beam. At this stage, no change in the magnetic configuraton is required. We will work in the standard 100_44_64.

A basic characterization of the plasmas will require the interferometer and Thomson Scattering diagnostics.
A good estimation of experimental electron density and temperature profiles at times of interest will be required for the simulations. In addition to the Thomson measurements, the He beam will help in fitting the profiles in the plasma edge and the NPA will be required to have some information about the ion temperature.
The Doppler reflectometer and the dual HIBP are basic for the characterization of the potential oscillations.

A characterization of the fast ions populations by means of passive spectrroscopy and/or luminiscent probes will be very convenient.

Required resources:
* Number of plasma discharges or days of operation: one experimental day.
* Essential diagnostic systems:

- Interferometry
- Thomson Scattering
- Neutral Particle Analyzer
- Helium beam
- The double Heavy Ion Beam probe
- Doppler reflectometer
- [passive spectrroscopy and/or luminiscent probes]

* Type of plasmas (heating configuration): stable ECRH plasmas in the standard configuration.
* Specific requirements on wall conditioning if any:
* 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 />

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

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

TJ-II:Excitation of zonal flow oscillations by energetic particles

2017-01-25T09:14:49Z

Sanedi:

== Experimental campaign ==
2017 Spring

== Proposal title ==
'''Excitation of zonal flow oscillations by energetic particles'''

== Name and affiliation of proponent ==
Edilberto Sánchez, José Luis Velasco, Kieran McCarthy, Iván Calvo

== Details of contact person at LNF (if applicable) ==
Edilberto Sánchez

== Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)==

'''Motivation'''

In stellarators the zonal flows (ZF) undergo several oscillations depending on the magnetic geometry and the plasma conditions. First, a Geodesic Acoustic Mode (GAM) oscillation, similar to that in tokamaks, appears, whose collisionless damping strongly depends on the rotational transform. A new oscillation, at a lower frequency, recently discovered theoretically <ref>Mishchenko PoP 2008</ref>, appears in stelallarators that is not present in quasisymmetric devices. In TJ-II, both oscillations have been found in simulations <ref>Sánchez PPCF 2013</ref> and the low frequency one has been identified for the first time during pellet injection experiments <ref>Alonso PRL 2017</ref>. Other experimental evidences appear to be related to zonal flow oscillations, both low frequency <ref>Pedrosa PoP 2008</ref> and GAM <ref>Castejón PPCF 2016</ref>.

According to gyrokinetic simulations, the GAM and LFO oscillations are damped in the TJ-II geometry (even collisionlessly) and the necessary driving mechanism has not been identified so far. The turbulence can drive (non-linearly) these oscillations, but it is not the only option as driving mechanism.
In tokamaks it has been found that energetic particles can drive the GAM oscillation (EGAMs) <ref>Zarzoso PRL 2013 and reference therein</ref>, but in stellarators there are less evidences <ref>Sun EFL 2016</ref> and the oscillation fauna is wider than in tokamaks.

'''Objectives'''

In this experiment we plan to study the excitation of ZF oscillations by energetic particles in TJ-II.

We will generate fast ions by means of the diagnostic neutral beam injector and try to measure oscillations in the zonal potential, if we are able to generate them. If so, we will characterize their spectrum and study the dependency with parameters: beam intensity, beam energy, and ion and electron temperatures.

The experimental results will be compared to dedicated gyrokinetic simulations.

== If applicable, International or National funding project or entity ==
N/A

== Description of required resources ==

The experiments will be carried out in ECRH plasmas that will provide a ground state to add the fast ions from the neutral beam. At this stage, no change in the magnetic configuraton is required. We will work in the standard 100_44_64.

A basic characterization of the plasmas will require the interferometer and Thomson Scattering diagnostics.
A good estimation of experimental electron density and temperature profiles at times of interest will be required for the simulations. In addition to the Thomson measurements, the He beam will help in fitting the profiles in the plasma edge and the NPA will be required to have some information about the ion temperature.
The Doppler reflectometer and the dual HIBP are basic for the characterization of the potential oscillations.

A characterization of the fast ions populations by means of passive spectrroscopy and/or luminiscent probes will be very convenient.

Required resources:
* Number of plasma discharges or days of operation: one experimental day.
* Essential diagnostic systems:

- Interferometry
- Thomson Scattering
- Neutral Particle Analyzer
- Helium beam
- The double Heavy Ion Beam probe
- Doppler reflectometer
- [passive spectrroscopy and/or luminiscent probes]

* Type of plasmas (heating configuration): stable ECRH plasmas in the standard configuration.
* Specific requirements on wall conditioning if any:
* 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 />

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

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

TJ-II:Excitation of zonal flow oscillations by energetic particles

2017-01-22T16:13:51Z

Sanedi: Created page with "== Experimental campaign == 2017 Spring == Proposal title == '''Excitation of zonal flow oscillations by energetic particles''' == Name and affiliation of proponent == Edilb..."

== Experimental campaign ==
2017 Spring

== Proposal title ==
'''Excitation of zonal flow oscillations by energetic particles'''

== Name and affiliation of proponent ==
Edilberto Sánchez, José Luis Velasco, Iván Calvo

== Details of contact person at LNF (if applicable) ==
Edilberto Sánchez

== Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)==

'''Motivation'''

In stellarators the zonal flows (ZF) undergo several oscillations depending on the magnetic geometry and the plasma conditions. First, a Geodesic Acoustic Mode (GAM) oscillation, similar to that in tokamaks, appears, whose collisionless damping strongly depends on the rotational transform. A new oscillation, at a lower frequency, recently discovered theoretically [Mishchenko PoP 2008], appears in stelallarators that is not present in quasisymmetric devices. In TJ-II, both oscillations have been found in simulations [Sánchez PPCF 2013] and the low frequency one has been identified for the first time during pellet injection experiments [Alonso PRL 2017]. Other experimental evidences appear to be related to zonal flow oscillations, both low frequency [Pedrosa PoP 2008] and GAM [Castejón PPCF 2016].

According to gyrokinetic simulations, the GAM and LFO oscillations are damped in the TJ-II geometry (even collisionlessly) and the necessary driving mechanism has not been identified so far. The turbulence can drive (non-linearly) these oscillations, but it is not the only option as driving mechanism.
In tokamaks it has been found that energetic particles can drive the GAM oscillation (EGAMs) [Zarzoso PRL 2013 and reference therein], but in stellarators there are less evidences [Sun EFL 2016] and the oscillation fauna is wider than in tokamaks.

'''Objectives'''

In this experiment we plan to study the excitation of ZF oscillations by energetic particles in TJ-II.

We will generate fast ions by means of the diagnostic neutral beam injector and try to measure oscillations in the zonal potential, if we are able to generate them. If so, we will characterize their spectrum and study the dependency with parameters: beam intensity, beam energy, and ion and electron temperatures.

The experimental results will be compared to dedicated gyrokinetic simulations.

== If applicable, International or National funding project or entity ==
N/A

== Description of required resources ==

The experiments will be carried out in ECRH plasmas that will provide a ground state to add the fast ions from the neutral beam. At this stage, no change in the magnetic configuraton is required. We will work in the standard 100_44_64.

A basic characterization of the plasmas will require the interferometer and Thomson Scattering diagnostics.
A good estimation of experimental electron density and temperature profiles at times of interest will be required for the simulations. In addition to the Thomson measurements, the He beam will help in fitting the profiles in the plasma edge and the NPA will be required to have some information about the ion temperature.
The Doppler reflectometer and the dual HIBP are basic for the characterization of the potential oscillations.

A characterization of the fast ions populations by means of passive spectrroscopy and/or luminiscent probes will be very convenient.

Required resources:
* Number of plasma discharges or days of operation: one experimental day.
* Essential diagnostic systems:

- Interferometry
- Thomson Scattering
- Neutral Particle Analyzer
- Helium beam
- The double Heavy Ion Beam probe
- Doppler reflectometer
- [passive spectrroscopy and/or luminiscent probes]

* Type of plasmas (heating configuration): stable ECRH plasmas in the standard configuration.
* Specific requirements on wall conditioning if any:
* 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)

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

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