On the structure of resistive MHD intermediate shocks

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA06p06539· OSTI ID:5834730

Hau, L N; Sonnerup, B U.O. ^[1]

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1. Dartmouth College, Hanover, NH (USA)

An overview is presented of the resistive steady state structure of intermediate MHD shocks, i.e., shocks that effect a transition from super-alfvenic to sub-alfvenic flow. The results are presented in terms of magnetic hodograms in which the two components of the magnetic field tangential to the shock surface are plotted against each other. By performing fixed-point analysis in this plane, at the possible upstream and downstream states of these shocks, and by solving the one-dimensional, steady state, resistive, nonviscous MHD equations numerically, it is found that three basic types of hodogram topology exist, describing the resistive intermediate shock structure. These topologies are characterized by the normal flow speed (in the shock frame) relative to the fast-wave speed and the sound speed at the upstream and downstream states. Fast-mode and slow-mode shocks are contained within these hodograms as well. In brief summary, it is found that all intermediate shocks that have an upstream normal flow speed, v{sub x1}, less than the local small-amplitude fast-mode wave speed, c{sub f1}, and a downstream normal flow speed, v{sub x2}, greater than the local small-amplitude slow-mode wave speed, c{sub s2}, have a unique magnetic structure consisting mainly of a rotation of the tangential magnetic field, accompanied by a more or less pronounced change in field magnitude. The structures of both weak and strong superfast intermediate shocks are found to be nonunique. When the intermediate shock involves a transition from supersonic (V{sub x1} > c{sub 1}) to subsonic (V{sub x2} < c{sub 2}) conditions, the resistive intermediate shock structure usually contains a discontinuous substructure consisting of a gas dynamic shock in which dissipation processes other than resistivity, namely viscosity and/or heat conductivity, are dominant.

• OSTI ID: 5834730
• Journal Information: Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 94:A6; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics &amp; Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
FLUID FLOW
FLUID MECHANICS
HELIOSPHERE
HYDRODYNAMICS
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MECHANICS
MOTION
NUMERICAL SOLUTION
PHYSICAL PROPERTIES
ROTATION
SHOCK WAVES
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOLAR WIND
STEADY-STATE CONDITIONS
SUBSONIC FLOW
SUPERSONIC FLOW
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES