Accession Number : AD0697670

Title :   THERMAL INSTABILITIES IN INTERSTELLAR GAS HEATED BY COSMIC RAYS.

Descriptive Note : Technical rept.,

Corporate Author : STANFORD UNIV CALIF INST FOR PLASMA RESEARCH

Personal Author(s) : Goldsmith,D. W.

Report Date : JUL 1969

Pagination or Media Count : 40

Abstract : The paper presents a theoretical study of therma instabilities in interstellar gas that is heated by cosmic rays. As a result of such instabilities, perturbations within the hot, rarefield intercloud medium can grow in magnitude and cause a transition to a dense, cool gas phase in pressure equilibrium with the intercloud phase. Analytic expressions give a growth rate from the linearized hydrodynamic equations, and a computer program follows the perturbations into the non-linear regime. The equations of constraint allow for changes in the ionization of the interstellar gas and for the presence of a magnetic field component perpendicular to the wave vector of the perturbation. The computer program was also used to study a one-dimensional spherical piston problem, as an approximation to the advance of a supernova shell into the initially homogeneous intercloud medium. (Author)

Descriptors :   (*INTERSTELLAR MATTER, THERMAL STABILITY), COSMIC RAYS, HEATING, PHASE STUDIES, IONIZATION, RECOMBINATION REACTIONS, THERMAL CONDUCTIVITY, HYDRODYNAMICS, PERTURBATION THEORY, NUMERICAL ANALYSIS, THESES

Subject Categories : Astrophysics

Distribution Statement : APPROVED FOR PUBLIC RELEASE