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          Institute: MPI für Kernphysik     Collection: High-Energy Astrophysics     Display Documents

ID: 277679.0, MPI für Kernphysik / High-Energy Astrophysics
Magnetic Field Amplification in Tycho and other Shell-type Supernova Remnants
Authors:Völk, Heinrich J.; Ksenofontov, Leonid; Berezhko, Evgeni
Publisher:Forschungszentrum Karlsruhe
Place of Publication:Karlsruhe
Date of Publication (YYYY-MM-DD):2005-12
Title of Proceedings:Contributions to the 29th International Cosmic Ray Conference, Pune, India, 2005
Start Page:233
End Page:236
Name of Conference/Meeting:29th International Cosmic Ray Conference
Place of Conference/Meeting:Pune, India
(Start) Date of Conference/Meeting
End Date of Conference/Meeting 
Review Status:not specified
Audience:Experts Only
Abstract / Description:It is shown that amplification of the magnetic field in supernova remnants (SNRs) occurs in all seven objects
where morphological measurements are presently available in the hard X-ray continuum at several keV. For the
three archetypical objects (SN 1006, Cas A and Tycho's SNR) to which nonlinear time-dependent acceleration
theory has been successfully applied up to now, the global theoretical and the local observational eld strengths
agree very well, suggesting that all young SNRs exhibit the amplification effect as a result of very efficient
acceleration of nuclear cosmic rays (CRs) at the outer shock. A fourth such case is presented elsewhere in
these Proceedings for the remnant of Kepler's SN, with the same conclusion. We consider field amplification
as a measure of nuclear CR acceleration. The above results are also used to investigate the time evolution
of field amplification in young SNRs. They rather clearly show that the ratio of the magnetic field energy
density and the kinetic energy density of gas flow into the shock is of the order of a few percent if the shock
speed is high enough, Vs>103 km/s. It implies that the escape of the highest energy nuclear particles from their sources becomes progressively important with age, reducing also the cutoff in the π0-decay gamma-ray emission spectrum with time after the end of the sweep-up phase.
Free Keywords:Supernova Remnants
External Publication Status:published
Document Type:Conference-Paper
Affiliations:MPI für Kernphysik/Group H. J. Völk
External Affiliations:Yu.G.Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 677980 Yakutsk, Russia
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