Robert B. Sheldon and Scott Spurrier
March 9, 2001
Physics Dept., The University of Alabama in Huntsville, Huntsville, AL 35899
The observation of 40 keV field-aligned plasma flows, [Sheldon et.
al., 1998] has been conjectured as the result of a space-charge driven
instability generating kV parallel potentials [Sheldon, 1999], which occur
whenever hot plasma drifts in an inhomogeneous magnetic field. Such
conditions occur in almost any magnetic field that interacts with an
energetic plasma; at the Earth, the Sun, Jupiter, and perhaps even
astrophysical magnetospheres of stars, black holes and active galactic
nuclei, all of which possess collimated flows. From this ubiquity,
we have looked for field-aligned flows in a table top plasma experiment
involving a permanent magnet and a DC discharge source of energetic
plasma. We emphasize that a one-fluid plasma theory such as
magnetohydrodynamics is incapable of describing a parallel potential
drop, and that most second order corrections to the theory predict weak
parallel voltages proportional to the thermal energy. In contrast, we show
photographs of the plasma and peculiar high-voltage ( 500eV
kT)
discharges suggestive of a large field-aligned potential drop. We propose
that this may be a manifestation of the Quasi-Neutral Catastrophe
heretofore neglected by
space and laboratory plasma physicists, which may unify many disparate
observations.