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TJ-II: Searching for AEs suppression scenarios using off-axis ECCD: Difference between revisions
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TJ-II: Searching for AEs suppression scenarios using off-axis ECCD (view source)
Revision as of 18:31, 16 October 2019
, 16 October 2019→Preferred dates and degree of flexibility
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The goal of the proposal is to find ECRH launching configurations for which the amplitude of | The goal of the proposal is to find ECRH launching configurations for which the amplitude of | ||
NBI-driven Alfvén Eigenmodes (AEs) is mitigated. Many | NBI-driven Alfvén Eigenmodes (AEs) is mitigated. Besides the interest that such scenarios have for the fast particles topic, studies of coupling between NBI-driven AEs and low frequency zonal flows may also benefit from them. | ||
Many scenarios making use of different "control" parameters | |||
have already been tested in past experimental sessions, showing always strong changes in AEs activity. | 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 | Plasma density variations and changes of the rotational transform profile due to the | ||
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changes in plasma parameters, being the most promising the one employing ECCD. | changes in plasma parameters, being the most promising the one employing ECCD. | ||
In this particular case we intend to investigate the effect of | In this particular case we intend to investigate the effect of | ||
off-axis ECCD at different plasma radius | off-axis ECCD at different plasma radius. | ||
== Experimental plan == | == Experimental plan == | ||
[[File:imagen1.png |thumb|right|300px| Figure 1. Heating scheme. ECH1 beam, used to induce current, is launched with two different power levels]] | [[File:imagen1.png |thumb|right|300px| Figure 1. Heating scheme. ECH1 beam, used to induce current, is | ||
launched with two different power levels for gyrotron stability purposes]] | |||
Until now, only ECCD on-axis has been investigated. | Until now, only ECCD on-axis has been investigated. We will now try to modify the rotational transform profile by inducing ECCD off-axis with | ||
We will now try to modify the rotational transform profile by inducing ECCD off-axis with | different levels of power at different plasma radius. The heating power set-up shown in figure 1 will allow | ||
different levels of power at different plasma radius. The heating power set-up shown in figure 1 will | us to investigate the effect of ECCD using different combinations of ECH1 beam power and ECCD efficiency. | ||
With this set-up, launching ECH2 power with <math>n_{||}=0</math> , only a small amount of ECCD current will be induced by the | |||
ECH1 beam during the ECRH phase while the larger amount of ECCD will be induced during the NBI phase by increasing the ECH1 beam power. For stability purposes ECH1 must be working at low power from the begginning of the shot until higher power is requested. | |||
== Description of required resources == | == Description of required resources == | ||
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* Essential diagnostic systems: Besides the common shot to shot diagnostics (ECE, Thomson, Interferometry, Radiation), all systems providing edge plasma profiles are needed. Moreover, HIBP, Doppler Reflectometer, Mirnov coils (both helicoidal and poloidal arrays) and CNPA meaurements are mandatory. MSE would also be desirable to measure changes induced by ECCD. | * Essential diagnostic systems: Besides the common shot to shot diagnostics (ECE, Thomson, Interferometry, Radiation), all systems providing edge plasma profiles are needed. Moreover, HIBP, Doppler Reflectometer, Mirnov coils (both helicoidal and poloidal arrays) and CNPA meaurements are mandatory. MSE would also be desirable to measure changes induced by ECCD. | ||
* Type of plasmas (heating configuration): ECRH + NBI-1 hydrogen plasmas following the heating scheme shown in Figure 1. | * Type of plasmas (heating configuration): ECRH + NBI-1 hydrogen plasmas following the heating scheme shown in Figure 1. | ||
== Preferred dates and degree of flexibility == | == Preferred dates and degree of flexibility == | ||
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of the proposal submission | of the proposal submission | ||
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