Electrodeless plasma acceleration system using rotating magnetic field method

We have proposed Rotating Magnetic Field (RMF) acceleration method as one ofelectrodeless plasma accelerations. In our experimental scheme, plasma generated by an rf(radio frequency) antenna, is accelerated by RMF antennas, which consist of two-pair,opposed, facing coils, and these antennas are outside of a discharge tube. Therefore,there is no wear of electrodes, degrading the propulsion performance. Here, we willintroduce our RMF acceleration system developed, including the experimental device, e.g.,external antennas, a tapered quartz tube, a vacuum chamber, external magnets, and apumping system. In addition, we can change RMF operation parameters (RMF applied currentIRMF and RMF current phase difference ϕ,focusing on RMF current frequency fRMF) by adjusting matchingconditions of RMF, and investigate the dependencies on plasma parameters (electron densityne and ion velocity vi); e.g.,higher increases of ne and vi(∼360 % and 55 %, respectively) than previous experimental results were obtained bydecreasing fRMF from 5 MHz to 0.7 MHz, whose RMF penetrationcondition was better according to Milroy’s expression. Moreover, time-varying component ofRMF has been measured directly to survey the penetration condition experimentally