Radial energy flux during destabilized Alfven eigenmodes

摘要

Equations which determine the density of the transverse energy flux generated by destabilized Alfven eigenmodes in bounded plasmas are derived and analyzed. It is shown that the energy flux can be directed outwards or inwards. The value, direction, and radial distribution of the flux depend on the instability growth rate and location of the regions driving the instability. The transverse flux provides the growth of the mode amplitude in places where the instability drive is weak or absent. Moreover, it provides the spatial channeling of the energy [the energy transfer by the mode predicted by Kolesnichenko et al. [Phys. Rev. Lett. 104, 075001 (2010)]] from unstable regions to the regions where damping dominates. This improves the plasma energy confinement in the case of an inward flux and deteriorates the confinement in the contrary case. The energy fluxes during some Alfven instabilities in the tokamak-reactor ITER and the Wendelstein 7-X stellarator are evaluated. Published by AIP Publishing.