SNOWPLOW AND MULTIPLE BOUNCE MODELS FOR THE EXPANSION AND RETARDATION OF A PLASMA EXPLOSION BUBBLE. Chap. 1 OF THEORETICAL STUDY OF HYDROMAGNETIC STABILITY AND TURBULENCE. INVESTIGATIONS AND DETAILED RESULTS. Annual Report, Period: January 1-December 31, 1961

Technical Report · Wed Oct 31 04:00:00 EST 1962

OSTI ID:4812547

Kruskal, M D; Bernstein, I B; Kulsrud, R M

Two models describing the expansion of a plasma bubble into an ambient ionized atmosphere are studied. The plasma bubble is a cold perfectly conducting medium which expands uniformly from zero radius. The external environment is assumed to decelerate the expansion by exerting constant back pressure at the interface separating the freely expanding medium from its surrounding. The snowplow model assumes that any element of uniformly expanding plasma which strikes the interface adheres to the interface. The multiple bounce model assumes that any element of the freely expanding plasma which strikes the interface is specularly reflecting therefrom. Since the interface is decelerating, a given element of fluid collides again and again as the interface catches up with it. The muItiple bounce picture leads to the formation of a surface layer containing particles which are reflected at least once by the interface. The simpler snowplow model is a good approximation to the multiple bounce model so long as the thickness of this surface layer is small compared with the retardation of the interface from the position it would have if the expansion were an ideal free expansion. The muitiple bounce model is plausible as long as this surface layer thickness is much greater than the distance of penetration of the magnetic field predicted by microscopic theory. Both models are reasonable representations of the independent expansion in the early expansion period and at altitudes where the effect of neutrals can be neglected. (auth)

• Research Organization: Radio Corp. of America. Missile and Surface Radar Div., Moorestown, N.J.
• NSA Number: NSA-16-022711
• OSTI ID: 4812547
• Report Number(s): AFSWC-TDR-62-12(Vol.II)(Chap.1
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ATMOSPHERE
BUBBLES
EXPANSION
IONIZATION
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
PHYSICS
PINCH
PLASMA
REFLECTION
SNOW PLOW MODEL
SURFACES