345
edits
TJ-II: Influence of edge radial electric fields on impurity transport: Difference between revisions
Jump to navigation
Jump to search
TJ-II: Influence of edge radial electric fields on impurity transport (view source)
Revision as of 17:17, 21 January 2022
, 21 January 2022→Details of contact person at LNF
| (4 intermediate revisions by the same user not shown) | |||
| Line 7: | Line 7: | ||
== Name and affiliation of proponent == | == Name and affiliation of proponent == | ||
Dominique Escande, Marseille University | Dominique Escande, Marseille University | ||
Eduardo de la Cal, Igor Voldiner, Marian Ochando, Carlos Hidalgo, Ciemat | |||
== Details of contact person at LNF == | == Details of contact person at LNF == | ||
Eduardo de la Cal, Ciemat | |||
== Description of the activity == | == Description of the activity == | ||
| Line 18: | Line 19: | ||
Goal. It is proposed to investigate the role of edge radial electric fields and low frequency zonal flows on impurity (He) inward transport in the plasma boundary region in the TJ-II stellarator. | Goal. It is proposed to investigate the role of edge radial electric fields and low frequency zonal flows on impurity (He) inward transport in the plasma boundary region in the TJ-II stellarator. | ||
Scenario. Experiments will be carried out in the proximity of the elctron-ion root transition. | Scenario. Experiments will be carried out in the proximity of the elctron-ion root transition and in the proximity to de NBI density limit. | ||
The ambipolarity condition (i.e. the equality of ion and electron fluxes) determining the radial neoclassical electric field has two stable roots in stellarators: the ion root with typically negative Er, usually achieved in high density plasmas, and the electron root with positive Er, that is typically realized when electrons are subject to strong heating. In addition the neoclassical viscosity vanishes as electron – ion root transition [J.L. Velasco et al., PRL-2012]. This allows large deviations of Er from NC ambipolarity including the amplification of zonal flows [M.A. Pedrosa et al., PRL-2008]. The electron – ion root transition allows to modify DC radial electric fields in a continuos and controlled manner. | The ambipolarity condition (i.e. the equality of ion and electron fluxes) determining the radial neoclassical electric field has two stable roots in stellarators: the ion root with typically negative Er, usually achieved in high density plasmas, and the electron root with positive Er, that is typically realized when electrons are subject to strong heating. In addition the neoclassical viscosity vanishes as electron – ion root transition [J.L. Velasco et al., PRL-2012]. This allows large deviations of Er from NC ambipolarity including the amplification of zonal flows [M.A. Pedrosa et al., PRL-2008]. The electron – ion root transition allows to modify DC radial electric fields in a continuos and controlled manner. | ||
| Line 28: | Line 30: | ||
== Description of required resources == | == Description of required resources == | ||
Required resources: | Required resources: | ||
* Number of plasma discharges or days of operation: | * Number of plasma discharges or days of operation: 2 | ||
* Essential diagnostic systems: Fast caremas with triple boundle | * Essential diagnostic systems: Fast caremas with triple boundle | ||
* Type of plasmas (heating configuration): ECRH | * Type of plasmas (heating configuration): ECRH (electron - ion root) and NBI (density limit) | ||
* Specific requirements on wall conditioning if any: | * Specific requirements on wall conditioning if any: | ||
* External users: need a local computer account for data access: no | * External users: need a local computer account for data access: no | ||