Relativistic shock waves and the excitation of plerions

Conference · Mon Jan 07 04:00:00 EST 1991

OSTI ID:6138630

Arons, J ^[1]; Gallant, Y A ^[2]; Hoshino, Masahiro; Max, C E ^[3]; Langdon, A B ^[4]

---

1. California Univ., Berkeley, CA (USA)
2. California Univ., Berkeley, CA (USA). Dept. of Physics
3. California Univ., Livermore, CA (USA). Inst. of Geophysics and Planetary Physics
4. Lawrence Livermore National Lab., CA (USA)

The shock termination of a relativistic magnetohydrodynamic wind from a pulsar is the most interesting and viable model for the excitation of the synchrotron sources observed in plerionic supernova remnants. We have studied the structure of relativistic magnetosonic shock waves in plasmas composed purely of electrons and positrons, as well as those whose composition includes heavy ions as a minority constituent by number. We find that relativistic shocks in symmetric pair plasmas create fully thermalized distributions of particles and fields downstream. Therefore, such shocks are not good candidates for the mechanism which converts rotational energy lost from a pulsar into the nonthermal synchrotron emission observed in plerions. However, when the upstream wind contains heavy ions which are minority constituent by number density, but carry the bulk of the energy density, much of the energy of the shock goes into a downstream, nonthermal power law distribution of positrons with energy distribution N(E)dE {proportional to}E{sup {minus}s}. In a specific model presented in some detail, s = 3. These characteristics are close to those assumed for the pairs in macroscopic MHD wind models of plerion excitation. The essential mechanism is collective synchrotron emission of left-handed extraordinary modes by the ions in the shock front at high harmonics of the ion cyclotron frequency, with the downstream positrons preferentially absorbing almost all of this radiation, mostly at their fundamental (relativistic) cyclotron frequencies. Possible applications to models of plerions and to constraints on theories of energy loss from pulsars are briefly outlines. 27 refs., 5 figs.

• Research Organization: California Univ., Livermore, CA (USA). Inst. of Geophysics and Planetary Physics
• Sponsoring Organization: DOE; USDOE, Washington, DC (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6138630
• Report Number(s): UCRL-JC-105642; CONF-9106119--1; ON: DE91007623
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
CHARGED PARTICLES
COSMIC RADIO SOURCES
ELECTRIC FIELDS
ENERGY LOSSES
ENERGY-LEVEL TRANSITIONS
EXCITATION
FLUID MECHANICS
HEAVY IONS
HYDRODYNAMICS
IONS
LINEAR MOMENTUM
LOSSES
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MECHANICS
NEBULAE
PULSARS
SHOCK WAVES
STELLAR ATMOSPHERES
STELLAR MAGNETOSPHERES
SUPERNOVA REMNANTS
TRANSVERSE MOMENTUM