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TJ-II: Influence of edge radial electric fields on impurity transport: Difference between revisions
TJ-II: Influence of edge radial electric fields on impurity transport (view source)
Revision as of 18:35, 20 January 2022
, 20 January 2022→Description of the activity
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== Description of the activity == | == Description of the activity == | ||
Rational. It has been recently argued that the existence of a time delay in the feedback loop relating radiation and impurity production on divertor plates can affect the density limit <ref>D.F. Escande et al 2022 Nucl. Fusion 62 026001</ref>. Furthermore, recent experiments in the TJ-II stellarator have shown the presence and amplification of low frequency Zonal Flows in the vicinity of this limit <ref>D. Fernández-Ruiz et al 2021 Nucl. Fusion 61 126038 </ref>. Whether the threshold radiation value for the density limit would be partially affected by the amplitude of (fluctuating and DC) zonal flows as well as the role of radiation to reduce the free energy available to the turbulence and the ZF-drive are open questions. | Rational. It has been recently argued that the existence of a time delay in the feedback loop relating radiation and impurity production on divertor plates can affect the density limit <ref>D.F. Escande et al 2022 Nucl. Fusion 62 026001</ref>. Furthermore, recent experiments in the TJ-II stellarator have shown the presence and amplification of low frequency Zonal Flows in the vicinity of this limit <ref>D. Fernández-Ruiz et al 2021 Nucl. Fusion 61 126038 </ref>. Whether the threshold radiation value for the density limit would be partially affected by the amplitude of (fluctuating and DC) zonal flows as well as the role of radiation to reduce the free energy available to the turbulence and the ZF-drive are open questions. | ||