On Magnetic Field Amplification in Gamma-Ray Burst Sources

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dc.creatorBlackman, Eric G.
dc.date2002-11-10
dc.date2002-11-12
dc.date.accessioned2026-07-07T02:06:07Z
dc.date.available2026-07-07T02:06:07Z
dc.descriptionMagnetic fields play a dual role in gamma-ray bursts (GRBs). First, GRB and afterglow spectra (the latter interpreted as emission from external shocks) imply synchrotron radiation in a magnetic field that is a significant fraction of equipartition with the particle energy density. Second, magnetized rotators with $\sim 10^{15}$ Gauss field may power GRB by transporting Poynting flux to large distances where it dissipates and also drives an external shock. The field amplification at external shocks and in the engine involve separate processes. External shock fields are likely either seeded by a pre-GRB wind, or are amplified by two-stream plasma instabilities with MHD turbulence playing a subsequent role. In the engine, the large scale fields are likely produced by MHD helical dynamos, since flux accretion cannot easily compete with turbulent diffusion, and because structures must be large enough to rise to coronae before diffusing. Why helical dynamos are feasible, and their relation to the magnetorotational instability are among the points discussed.
dc.description12 pages LaTeX (Q&A at end), to appear in proceedings of the 1st Niels Bohr Summer Institute: "Beaming and Jets in Gamma-Ray Bursts", Copenhagen, Aug 2002
dc.identifierhttps://arxiv.org/abs/astro-ph/0211187
dc.identifierhttp://arxiv.org/abs/astro-ph/0211187
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/5312
dc.subjectAstrophysics
dc.titleOn Magnetic Field Amplification in Gamma-Ray Burst Sources
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