Design of a Compact Coaxial Magnetized Plasma Gun for Laboratory Studies of Plasma Relaxation

Summary form only given. We discuss the design of a compact coaxial magnetized plasma gun and its associated systems in detail. The plasma gun will be used for experimental studies of plasma relaxation to be conducted in the HELCAT facility at UNM. These studies will advance our knowledge of basic plasma physics in the areas of magnetic relaxation and space and astrophysical plasmas, including the evolution of active galactic jets. The gun will be powered by a 120 muF ignitron switched capacitor bank which is operated in a range of 5 ~ 10kV. High pressure gas will be puffed into an annular gap between the inner and outer coaxial electrodes. The applied high voltage ionizes the gas and creates a radial current sheet. The ~ 100kA discharge current generates toroidal flux and an external applied magnetic field provides poloidal flux. The axial JxB force ejects plasma out of the gun. If the JxB force exceeds the magnetic tension of the poloidal flux by a sufficient amount then a detached magnetized plasma will be formed. We plan to study the evolution of this plasma "bubble" as it interacts with a preexisting lower pressure background plasma.