Transport barrier for the radial diffusion due to the ExB drift motion of guiding centers in cylindrical confinement geometry
Résumé
We consider the radial transport of test particles due to the ExB drift motion in the guiding center approximation. In a configuration where the magnetic field is constant and uniform in linear devices or with neglecting toroidal effects in tokamaks, the ExB instability is one of the main sources of deconfinement of magnetized plasmas. Using an explicit expression to modify the electrostatic potential, we show that it is possible to construct a transport barrier which suppresses the radial transport. We propose an algorithm and a simulation of test particles for the implementation of this local modification computed from an electrostatic potential known on a spatio-temporal grid. The number of particles which escape the inner region defined by the barrier measures the efficiency of the control.
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