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Abstract
of the Dissertation:
Dynamics and Interaction of Plasma Currents with Large
Self-Magnetic Fields and their Relaxation Toward of Force-Free
Configuration.
by Hans Pfister
The
dynamics of current channels with large self-generated magnetic
fields in a background plasma and, in particular, their relaxation
toward a force-free configuration is investigated. Relaxation,
in the sense of the theoretical conception of Woltjer and
Taylor, to configurations regarded as minimum energy states,
described by the Beltrami equations 
is reexamined in light of Salingaros' theoretical results.
Detailed 3-D measurements in a quiescent laboratory plasma
of 10 m length and 50 cm diameter yield the magnetic field
B (x,y,z,t) and the plasma parameters, n(x,y,z,t),
kTe(x,y,z,t) and V(x,y,z,t) at several thousand measurement
locations. The plasma current J , plasma pressure p
=nkT, pressure gradient force 
and 
force are determined and relaxation toward a force-free configuration
that includes pressure gradient forces, i.e., that validity
of
= ,
is tested. The temporal relaxation of a single current channel
and the spatial relaxation of a dual current sustem is illustrated.
The return currents that prevent the two current channels
from twisting about ech other, after turn-off of the externally
applied electric field, are identified.
See
Also:
Gekelman, W., Maggs, J., Pfister, H., Experiments on the Interaction
of Current Channels in a Laboratory Plasma: Relaxation to the
Force- Free State, IEEE Transactions on Plasma Science,
V20, N6, 1992.
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