Plasma Transport Induced by Cyclotron Resonance

点击翻译按钮获取中文摘要

We obtained the following results on plasma transports induced by nonuniform or traveling radio-frequency (rf) fields with cyclotron frequencies. 1. It is theoretically found that plasma particles drift in the radially-outward direction under axisymmetric rf fields with radially-increasing amplitude. 2. This is demonstrated in the Q-machine experiment where electromagnetic fields around the ion-cyclotron frequency are inductively excited by a multi-turn loop antenna (m=0). The plasma profile in the vicinity of the antenna is periodically modified to be largely peaked and hollow with the applied rf period. This large-scale expansion and compression of the plasma finally leads to the radially outward ion-drift, resulting in a high-energy ion collision with the antenna. 3. Far from the antenna along the plasma flow, on the other hand, radial profiles of density and ion perpendicular temperature show stationary peaks at the plasma-column center, where antenna near-fields spatially damp but a plasma (ion Berstein) wave still persists. 4. In order to explain this peaking phenomenon observed, a new mechanism is pro-posed on plasma particle drifts due to perpendicularly traveling waves with cyclo-tron frequencies. The theory including physical picture, analytic solution and numerical analysis is successfully developed. 5. According to our theory it is expected that plasma particles drift in the radi-ally-outward or -inward direction, depending on the propagation direction of rf fields. Thus, we continue to demonstrate this transport principle experimentally by setting an antenna array in the Q-machine, where the azimuthal mode of traveling waves is externally controlled.