Accession Number:

ADA200754

Title:

Models of the Aneurysm in Expanding Laser-Plasma

Descriptive Note:

Technical rept. 2 May 1985-31 Jul 1988

Corporate Author:

MISSION RESEARCH CORP ALBUQUERQUE NM PLASMA SCIENCES DIV

Report Date:

1988-07-31

Pagination or Media Count:

96.0

Abstract:

This report describes theoretical models of laser plasma experiments in which hot laser-irradiated target debris expands into few Torr background gas. The most interesting characteristics of these experiments are the formation and evolution of a spherical blast wave, and in some cases, the appearance of one or more distinctive protuberances or aneurysms on the expanding wave. Many possible mechanisms for the formation of these structures have been suggested, ranging from instabilities in the blast wave itself to the effects of jets of material ejected from the target. Many of these mechanisms are of interest to the problem of early-time structuring in high altitude nuclear bursts. This report discusses a series of magnetohydrodynamic models that accurately describe this phenomenon, and identify the processes that mold the blast wave and the aneurysm. In most cases the aneurysm can be explained by a channel heating mechanism due to inverse bremsstrahlung in the laser channel. A simple model is derived that clearly shows this effect and matches the detailed two-dimensional models as well as the experimental results. The effects of laser-target interaction, thermal conduction, radiation cooling, multiple materials, self-generated magnetic fields, and ambient magnetic fields are included and discussed.

Subject Categories:

  • Plasma Physics and Magnetohydrodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE