Behavior of a Cold Ion Plasma in a Toroidal Octupole
J. C. Sprott
Department of Physics, University
of Wisconsin, Madison, Wisconsin 53706
(Received 6 October 1969)
By raising the background hydrogen gas pressure to ~ 10^-4 Torr and injecting
10-100 kW of 700-9000 MHz microwave power for ~ 100 microsec, an afterglow
plasma with n ~ 10^9 - 10^11 /cc and kTi < kTe ~ 1 eV can be produced
in the Wisconsin toroidal octupole. The particle lifetime is ~ 3 msec,
or somewhat longer than for a hot ion, gun injected plasma, and most (~
80%) of the plasma is lost to the hoops. The electron temperature decays
rapidly as a result of inelastic electron-neutral collisions. By changing
the magnetic field strength and microwave frequency, the density distribution
can be varied, and a variety of fluctuations produced. These fluctuations
do not appear to be an important source of plasma loss.
Ref: J. C. Sprott, Phys. Fluids 13,
The complete paper is available in PDF format.
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