OBSERVATION OF ION HEATING IN A FAST-FLOWING PLASMA FOR AN ADVANCED PLASMA THRUSTER

摘要

The first observation of the ion cyclotron resonance heating by RF waves is attained in a fast flowing plasma produced by Magneto-Plasma-Dynamic arcjet operated with an externally applied magnetic field in the HITOP device. RF waves with an ion cyclotron range of frequency are excited by a helically-wound antenna. Dispersion relations of the propagating waves are measured and compared with theoretical ones. Effects of ion heating are investigated from the increase in an ion temperature T_i and a plasma thermal energy W_⊥ measured by a diamagnetic coil during the wave excitation, and an increase in the plasma thermal energy is clearly observed. The heating efficiency is compared for several magnetic field configurations and strengths and no clear indication of cyclotron resonance, which suggests that the ion collisional effect is dominant in the high density plasma. When the ratio of ion cyclotron frequency to ion-ion collisional one becomes high, features of ion cyclotron resonance are observed.