Simulational study on losses of neutral beam-injected energetic ions via collisional ripple transport in the low aspect ratio helical system CHS

摘要

Confinement and loss properties of tangentially co-injected beam ions have been studied for a standard configuration of the Compact Helical System (R_ax/B_t=0.921 m/1.9 T) by use of the global particle simulation code DELTA5D. Both ripple transport and collisions with a background plasma are taken into account. It has appeared that partially thermalized, pitch-angle scattered beam ions are dominantly lost at the small major radius side. It has also been shown that the negative potential can enhance beam ions losses.