Ion ring propagation in a magnetized plasma

Abstract

The propagation of an ion ring in a 2.5 m long, 0.30 m diam magnetized plasma column was studied using an axial array of magnetic probes and fast proton detectors, a microwave interferometer, and a grating spectrometer. The ring propagated with an initial axial velocity 3×106 m/sec, about four times the Alfvén speed in the plasma, and excited damped magnetosonic waves whose peak amplitude depended on the plasma return current. The plasma electrons were heated by about 1 eV in response to the ring, as measured by the Hγ line-to-continuum intensity ratio. This heating is primarily attributed to classical Coulomb collisions, although about 1%–10% can be attributed to the collective ring–plasma interaction. The collective interaction had no measurable effect on the dynamics of the ion ring, consistent with theoretical models, given the beam, plasma, and magnetic-field parameters in the experiment.

MHD Activity in an Extremely High-Beta Compact Toroid

“…Since the 1990's, a variety of alternative formation methods have emerged (Ono, Y et al, 1993;Gerhardt et al 2008;Slough & Miller, 2000;Knight & Jones, 1990;A. Hoffman et al, 2002;Guo et al, 2007;Logan et al, 1976;Davis, 1976;Greenly et al, 1986;Schamiloglu et. al., 1993).…”

“…Recently initiated new formation methods include (1) counter-helicity spheromakmerging (CHSM) (Yamada et al, 1990;Ono et al, 1993;Gerhardt et al 2008), (2) rotating magnetic field (RMF) (Slough & Miller, 2000;Knight & Jones, 1990;A. Hoffman et al, 2002;Guo et al, 2007), (3) field-reversed mirror configuration (FRM) driven by neutral beam injection (NBI) (Logan et al, 1976), relativistic electron beam (REB) (Davis, 1976), and intense light ion beam (ILIB) injections (Greenly et al, 1986;Schamiloglu et. al., 1993).…”

Advances in singly connected closed field line plasma devices and extrapolation to POP level experiments and reactors

“…[7] However, attempts to accomplish the same thing with ion beams, which would be required for practical fusion, were unsuccessful. [8] Field reversal was then pursued in high voltage theta-pinches through trapping some initial reverse bias field, which then reconnected with a rapidly applied forward field. [9] This method of producing field reversal with diamagnetic currents was very successful, and the resulting topologies were named fieldreversed-configurations (FRC).…”

“…Although this was unsuccessful, probably for reasons related to the lack of success in the 2XIIB experiments, field reversing electron rings were produced by Professor Hans Fleishmann at Cornell University using fast injection of energetic electrons [7]. However, attempts to accomplish the same thing with ion beams, which would be required for practical fusion, were unsuccessful [8]. Field reversal was then pursued in high voltage theta-pinches through trapping some initial reverse bias field, which then reconnected with a rapidly applied forward field [9].…”