TJ-II: Searching for AEs suppression scenarios using off-axis ECCD: Difference between revisions

TJ-II: Searching for AEs suppression scenarios using off-axis ECCD (view source)

Revision as of 16:32, 16 October 2019

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 == Background ==
-[[File:imagen1.png |thumb|right|300px| Figure 1. Heating scheme. ECH2 beam is launched with two different power levels]]
+The goal of the proposal is to find ECRH launching configurations for which the amplitude of
+NBI-driven Alfvén Eigenmodes (AEs) is mitigated. Many different scenarios making use of different "control" parameters
+have already been tested in past experimental sessions, showing always strong changes in AEs activity.
+Plasma density variations and changes of the rotational transform profile due to the
+many contributions to the total plasma current (NBCD, ECCD, Bootstrap current) are the parameters
+with the higher impact. However, although inducing modifications in the general spectrum of the excited modes,
+none of the investigated scenarios show a clear possibility to suppress AEs without inducing large
+changes in plasma parameters. In this particular case we intend to investigate the effect of off-axis ECCD at different
+plasma radius.
-The goal of the proposal is to find ECRH launching configurations for which the amplitude of
-NBI-driven Alfvén Eigenmodes is mitigated. Many different scenarios have already been tested, showing always
-strong changes in AEs activity related to changes in plasma conditions or to changes in rotational transform profiles.
-increasing density or using ON-axis ECCD to modify iota and . some of this. In this particular case we intend to investigate the effect of off-axis ECCD at different
+In this particular case we intend to investigate the effect of off-axis ECCD at different
 plasma radius. The heating power set-up shown in figure 1 will allows us to investigate the effect of ECCD with different combinations of power and ECCD efficiency. Studies of coupling between NBI-driven AEs and low frequency zonal flows will benefit from scenario in which AEs activity can be altered without inducing large changes in plasma conditions.