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BEGIN:VEVENT
SUMMARY:MHD simulations of magnetic island stabilization
DTSTART:20161028T103000
DTEND:20161028T113000
DTSTAMP:20260929T171559Z
UID:716b74358b66865c39a04a22dd97d8e0db71d0b2d6c22cc3c1c21920
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Olivier Février\nCEA-Cadarache\, F\nThe confinement degra
 dation of tokamak plasma by magnetic islands motivates to better understan
 d their possible suppression using Electron Cyclotron Current Drive (ECCD)
 . In this seminar\, we present nonlinear simulations of this process with 
 the toroidal MHD code XTOR\, which has been extended to incorporate in Ohm
 's law a source term modelling the RF driven current resulting from the in
 teraction of the RF waves with the plasma. The implementation has been val
 idated\, in a single fluid MHD model\, against analytical theory regarding
  the stabilization efficiency\, while the effect of the 3D spatial localiz
 ation of the RF source appears to impact the island dynamics when the plas
 ma is nearly static. We then move on to the topic of control strategies\, 
 and evaluate the efficiency of several control methods. A basic control sy
 stem has been implemented in XTOR\, allowing testing advanced strategies t
 hat require feedback on island position or phase. We focus in particular o
 n the robustness of the control strategies towards the uncertainties that 
 apply on the control and ECCD systems\, such as the risk of misalignment o
 f the current deposition or the possible inability to generate narrow curr
 ent deposition. We show that the proper choice of stabilization strategy a
 llows alleviating such experimental uncertainties. Finally\, we present pr
 eliminary results on current work on the modeling of sawtooth control with
  ECCD. Depending on the radial location of a current deposition\, we obser
 ve that the shape and period of sawtooth are altered\, and the results obt
 ained with XTOR appears to be in qualitative agreement with experimental r
 esults.
LOCATION:PPB 019
STATUS:CONFIRMED
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