Accession Number:

ADA169099

Title:

Interaction of an Intense Relativistic Electron Beam with Preformed Channels.

Descriptive Note:

Interim rept.,

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Report Date:

1986-06-12

Pagination or Media Count:

82.0

Abstract:

The interaction of an intense relativistic electron beam REB with preformed channels in gaseous atmospheres demonstrates the effects of reduced density, avalanche ionization, preexisting conductivity, and channel currents. The intense REB for these experiments was produced from a field emission diode driven by the approx. 1.4 MV pulse from a pulse forming line. Peak REB currents up to approx. 16 kA, and current densities up to approx. 2 kAcm2 were achieved. The time history of the REB was approximately a half-sinewave of width 27 ns FWHM. Channels in the atmosphere were created using laser-guided electric discharges. Current-carrying reduced density channels were produced by applying a second discharge to the reduced density channel produced by the first discharge. Reduced density or pho sub 080, non-conducting channels were produced by the absorption of radiation from a pulsed CO2 laser in ammonia gas at background pressures of approx. 40 Torr approx. pho sub 020. Our results showed that reduced density had little effect of REB propagation except for the decreased scattering, until it was reduced so much that the generation of conductivity changes. Avalanche ionization in a uniform atmosphere increased the growth of instabilities but when avalanche ionization was confined to a reduced density channel the REB was always repelled or expelled from the channel. Pre-existing conductivity in the form of a conducting channel with conductivity, sigma or 0.1 Sm, also caused the REB to be repelled or expelled from the channel. However, the presence of a parallel channel current permitted the REB to be readily injected into the channel and guided along it with minimal losses.

Subject Categories:

  • Fusion Devices (Thermonuclear)
  • Nuclear Physics and Elementary Particle Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE