Hydrodynamical constraints on cosmic-ray acceleration in relativistic shocks

Journal Article · Sat Aug 01 04:00:00 EDT 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/165448· OSTI ID:5931691

Webb, G M

A two-fluid hydrodynamical model governing the transport of cosmic rays in a relativistically moving background plasma is developed. The equations are used to discuss the time asymptotic structure of a relativistic, plane-parallel shock wave significantly modified by first-order Fermi acceleration of cosmic rays. The model allows for an anisotropic cosmic-ray pressure tensor with pressure components parallel and perpendicular to the shock normal. It is surmised that the well-known energy threshold problem for diffusive shock acceleration that downstream particles have a large enough velocity to overtake the shock and subsequently scatter in the upstream medium before returning to the downstream medium may be expressed hydrodynamically by the condition V less than V(cr), where V is the fluid velocity relative to the shock and V(cr) is the relativistic cosmic-ray sound speed. Astrophysical implications of the results are briefly discussed. 65 references.

• Research Organization: Arizona Univ., Tucson
• OSTI ID: 5931691
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 319; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
ANISOTROPY
CONSTRAINTS
COSMIC RADIATION
FLUID FLOW
HYDRODYNAMIC MODEL
IONIZING RADIATIONS
MATHEMATICAL MODELS
PARTICLE MODELS
PLASMA
RADIATION PRESSURE
RADIATIONS
RELATIVISTIC PLASMA
SHOCK WAVES
STATISTICAL MODELS
THERMODYNAMIC MODEL
TWO-PHASE FLOW
WAVE PROPAGATION