TJ-II: Why fast reaction of plasma fluctuations to ECRH ?: Difference between revisions

TJ-II: Why fast reaction of plasma fluctuations to ECRH ? (view source)

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 == Description of the activity ==
-Why do ERCH/ ICRH avoid core impurity accumulation?. Significant progress has been reported regarding the physics understanding of empirical actuators like core heating to avoid impurity accumulation, including the following mechanisms: 1) A reduction of the background density gradient, leading to a reduction of the inward (neoclassical) convection of impurities; 2) An increase of turbulent diffusion; 3) The amplification of core temperature screening which would be relevant in core alpha-heating regimes; 4) The development of core plasma potential flux surface asymmetries.
+Why do ERCH/ ICRH avoid core impurity accumulation?. Significant progress has been reported regarding the physics understanding of empirical actuators like core heating to avoid impurity accumulation, including the following mechanisms: 1) A reduction of the background density gradient, leading to a reduction of the inward (neoclassical) convection of impurities; 2) An increase of turbulent transport; 3) The amplification of core temperature screening which would be relevant in core alpha-heating regimes; 4) The development of core plasma potential flux surface asymmetries.
 Why fast reaction of plasma fluctuations to ECRH?. This is the (challenging) question that we want to answer including experiments in TJ-II 2019 / 20, data analysis and model validation.
-From the theoretical perpective we should consider two mechanisms:
+From the theoretical perpective we should consider different mechanisms:
-The role of phase space driven instabilities <ref>S. Itoh and K. Itoh Scientific Reports 2, 860 (2012)</ref> and the role of plasma gradient driven instabilities <ref>E. Sánchez et al., Nucl Fusion 59, 076029 (2019)</ref>.
+The role of phase space driven instabilities <ref>S. Itoh and K. Itoh Scientific Reports 2, 860 (2012)</ref>; role of fast particles on MHD stability <ref>L. Gonzalo et al., Physics of Plasmas 23, 062319 (2016)</ref>; the role of plasma gradient driven instabilities <ref>E. Sánchez et al., Nucl Fusion 59, 076029 (2019)</ref>.
 From the experimental perspective the goal is the investigation of the influence of ECRH on / off power heating in the dynamics of edge & core fluctuations and transport: 1) Level of fluctuations, 2) Phase relation between density and potential fluctuations, 3) Turbulent ExB transport.