Plasma-gun-assisted field-reversed configuration formation in a conical θ-pinch

Abstract

Injection of plasma via an annular array of coaxial plasma guns during the pre-ionization phase of field-reversed configuration (FRC) formation is shown to catalyze the bulk ionization of a neutral gas prefill in the presence of a strong axial magnetic field and change the character of outward flux flow during field-reversal from a convective process to a much slower resistive diffusion process. This approach has been found to significantly improve FRC formation in a conical h-pinch, resulting in a $350% increase in trapped flux at typical operating conditions, an expansion of accessible formation parameter space to lower densities and higher temperatures, and a reduction or elimination of several deleterious effects associated with the pre-ionization phase. V C 2015 AIP Publishing LLC.

Miniaturized rotating magnetic field–driven plasma system: proof-of-concept experiments

“…Apparently, the Rotamak system features some similarity with the electrodeless Lorentz thruster (ELF), yet at a different scale. While the ELF operates in a 30-200 kW range and is intended for the applications in deep space [36,37], our device is designed for small satellites, and as such it will be smaller and more compact; early prototypes will be tested in a currently available space environment simulation system. Please find more details about the formulation and physical mechanisms which are responsible for igniting, maintaining and confining plasma in Rotamak-type devices in appendix A at the end of the paper.…”

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

“…Controlling magnetic field reconnection through programmed formation of the FRC proved to be crucial in creating stable, long-lived FRC plasmas [8]. For IPPT applications using conical theta-pinch geometries, research suggests it is possible to achieve this closed-flux equilibrium state on timescales faster than the ejection time of the plasmoid [29]. However, uncertainties exist regarding the scalability of FRTP to energy levels useful for electric propulsion, the sensitivity to preionization, the recovery of thermal energy obtained during compression, and the quantification of potentially significant plasma-wall interactions during field-reversal.…”

“…See . Schematic showing field-reversed theta pinch formation for closed magnetic flux thrusters: (a) preionization plasma is introduced into a background magnetic field; (b) a strong pulse of current generates a time-dependent magnetic field with polarity opposing the initial background magnetic field that compresses the plasma both radially and axially; (c) a closed magnetic field structure confines the plasma within a separatrix that divides the forward and reverse fields; and (d) magnetic field gradients in the axial direction accelerate and eject the resulting plasmoid (Reproduced/modified from [29]; with the permission of AIP Publishing. ).…”

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