Particle acceleration in multiple dissipation regions

Feb, 2004
12 pages
Published in:
  • Astrophys.J.Lett. 605 (2004) L69-L72
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Abstract: (arXiv)
The sharp magnetic discontinuities which naturally appear in solar magnetic flux tubes driven by turbulent photospheric motions are associated with intense currents. \citet{Par83} proposed that these currents can become unstable to a variety of microscopic processes, with the net result of dramatically enhanced resistivity and heating (nanoflares). The electric fields associated with such ``hot spots'' are also expected to enhance particle acceleration. We test this hypothesis by exact relativistic orbit simulations in strong random phase magnetohydrodynamic (MHD) turbulence which is forming localized super-Dreicer Ohm electric fields (EΩ/EDE_\Omega/E_D = 102...10510^2 ... 10^5) occurring in 2..15 % of the volume. It is found that these fields indeed yield a large amplification of acceleration of electrons and ions, and can effectively overcome the injection problem. We suggest in this article that nanoflare heating will be associated with sporadic particle acceleration.