Transport de particules induit par les Dents-de-Scie dans les palsmas de tokamak

Abstract : The radial transport of particles in tokamaks is one of the most stringent issues faced by the magnetic confinement fusion community, because the fusion power is proportional to the square of the pressure, and also because accumulation of heavy impurities in the core leads to important power losses which can lead to a "radiative collapse". Sawteeth and the associated periodic redistribution of the core quantities can significantly impact the radial transport of electrons and impurities. In this thesis, we perform numerical simulations of sawteeth using a nonlinear tridimensional magnetohydrodynamic code called XTOR-2F to study the particle transport induced by sawtooth crashes. We show that the code recovers, after the crash, the fine structures of electron density that are observed with fast-sweeping reflectometry on the JET and TS tokamaks. The presence of these structure may indicate a low efficiency of the sawtooth in expelling the impurities from the core. However, applying the same code to impurity profiles, we show that the redistribution is quantitatively similar to that predicted by Kadomtsev's model, which could not be predicted a priori. Hence finally the sawtooth flushing is efficient in expelling impurities from the core.
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https://pastel.archives-ouvertes.fr/pastel-00926428
Contributor : Timothée Nicolas <>
Submitted on : Thursday, January 9, 2014 - 3:30:40 PM
Last modification on : Monday, October 1, 2018 - 4:03:07 PM
Long-term archiving on : Thursday, April 10, 2014 - 3:20:23 PM

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Timothée Nicolas. Transport de particules induit par les Dents-de-Scie dans les palsmas de tokamak. Physique des plasmas [physics.plasm-ph]. Ecole Polytechnique X, 2013. Français. ⟨pastel-00926428⟩

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