Electrodeless plasma acceleration system using rotating magnetic field method

Abstract

COLLECTIONS This paper was selected as Featured ARTICLES YOU MAY BE INTERESTED INStudy on electromagnetic plasma propulsion using rotating magnetic field acceleration scheme Physics of Plasmas 24, 043505 (2017) We have proposed Rotating Magnetic Field (RMF) acceleration method as one of electrodeless 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 will introduce our RMF acceleration system developed, including the experimental device, e.g., external antennas, a tapered quartz tube, a vacuum chamber, external magnets, and a pumping system. In addition, we can change RMF operation parameters (RMF applied current I RMF and RMF current phase difference φ, focusing on RMF current frequency f RMF ) by adjusting matching conditions of RMF, and investigate the dependencies on plasma parameters (electron density n e and ion velocity v i ); e.g., higher increases of n e and v i (∼360 % and 55 %, respectively) than previous experimental results were obtained by decreasing f RMF from 5 MHz to 0.7 MHz, whose RMF penetration condition was better according to Milroy's expression. Moreover, time-varying component of RMF has been measured directly to survey the penetration condition experimentally. © 2017 Author (s)

Helicon high-density plasma sources: physics and applications

“…Basically, electromagnetic acceleration by the axial Lorentz force with the product of the induced azimuthal electron current j θ and external magnetic field B r , has been investigated. This j θ can be induced by (i) the rotating magnetic field (RMF) scheme [39,122,[200][201][202][203], the idea of which originates from the current drive method in FRC [204], (ii) the rotating electric field (REF) scheme [39,122,200,205], and (iii) a half cycle acceleration scheme with m = 0, low-frequency antenna current [39,42,122,200]. In order to induce a higher j θ , RMF (REF) penetration into a plasma is crucial [206] ( [207]), in addition to j θ penetration by the m = 0 scheme [39,122].…”

Spatial measurement in rotating magnetic field plasma acceleration method by using two-dimensional scanning instrument and thrust stand

“…Here, the developed scanning instrument has the lower height of a rail board, where movable mechanisms can move axially, considering the device geometry and disturbance of plasma flow. An electron density n e and an ion velocity v i have been measured to elucidate plasma performance by our electrodeless acceleration schemes, proposed under a Helicon Electrodeless Advanced Thruster (HEAT) project, 12,13 e.g., Rotating Magnetic Field (RMF) 14,15 acceleration [16][17][18] method. 12,13,19 Here, brief explanation of our plasma acceleration scheme will be described as follows, regarding the RMF acceleration scheme.…”

“…Previously, we have investigated plasma parameters as well as these dependencies on external operation parameters, e.g., radio frequency (rf) power applied to generation antenna, gas flow rate fr, in addition to RMF operation conditions. 17,18 Originally, the RMF method was utilized to induce an azimuthal current j θ to maintain a Field Reversed Configuration (FRC) in magnetically confined plasma fusion research. 13 We have tried applying this method to an electric thruster under the open magnetic field as the electrodeless plasma acceleration method, with an expectation to generate the axial Lorentz force derived from the cross product of the induced current by the RMF and radial component of the external field.…”

State-of-the-Art and Advancement Paths for Inductive Pulsed Plasma Thrusters

“…The electrodeless helicon plasma thruster (Figure 11a) leveraged the Large Mirror Device (LMD) configuration to study the acceleration of high density helicon plasmas [45]. It consists of a quartz tube that gradually expands as it enters a drift vacuum chamber.…”

“…The thruster performance is affected by the choice of propellant, but for any selected propellant the thruster is throttleable to higher power densities without any additional alterations to the overall thruster configuration [50]. [45]; licensed under a Creative Commons Attribution (CC BY) license), (b) MSNW electromagnetic plasma thruster (from [47]; reproduced with permission of the author), (c) Air Force Research Laboratory RP3-X thruster (from [49]), (d) MSNW electrodeless Lorentz force thruster (from [51]; reproduced with permission of the author), (e) CAD model of the University of Michigan RMF thruster (from [43]; reproduced with permission of Electric Rocket Propulsion Society).…”