Flux-limited heat flow in a double plasma device

Abstract

Electron heat flow has been studied in a double plasma device. Electrons of mean energies 5.1 eV and 2.3 eV were separated by a grid which was then pulsed to create a thermal wave moving in a large temperature gradient. Changes in the electrons' velocity distribution, concentration and energy agreed qualitatively with a simple theory based on transport in neutral gases. Thermoelectric effects reduced the heat flow by a factor of 5. This factor combined with the theory suggests a flux-limiting parameter with an upper limit of 0.15 for laser fusion. This value lies within the range found in experiments on plasmas heated by lasers.