Energy Conversion in Solar Flares

  1. J. H. Waite Jr.,
  2. J. L. Burch and
  3. R. L. Moore
  1. Peter A. Sturrock

Published Online: 18 MAR 2013

DOI: 10.1029/GM054p0181

Solar System Plasma Physics

Solar System Plasma Physics

How to Cite

Sturrock, P. A. (1989) Energy Conversion in Solar Flares, in Solar System Plasma Physics (eds J. H. Waite, J. L. Burch and R. L. Moore), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM054p0181

Author Information

  1. Center for Space Science and Astrophysics, Stanford University, Stanford, CA 94305

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875900742

Online ISBN: 9781118664315



  • Space plasmas;
  • Sun;
  • Magnetosphere;
  • Astrophysics


Flares involve a sequence of energy conversion processes beginning with the initial stressing of the magnetic field and ending with radiation. This article is concerned primarily with the processes by which magnetic energy is suddenly converted into other forms. We pay special attention to a sub-class of large flares, for which the flare process appears to begin with the activation of a filament. This activation may be either an MHD instability or a combination of MHD processes and reconnection. The main phase of particle acceleration, that may be either impulsive or gradual, is associated with the sudden release of magnetic energy in a large flux system. This may be attributed to reconnection that is due to, and also generates, fine-scale magnetic fluctuations. This process may be triggered either by the Kelvin-Helmholtz instability of an erupting filament, or by reconnection at a current sheet between adjacent flux systems. As a result of the fine-scale fluctuations, electric field components parallel to the magnetic field develop that can be responsible for the acceleration of large numbers of electrons to keV energies. Acceleration of electrons and ions to relativistic energies may be attributed to stochastic acceleration due to the same MHD fluctuations that are responsible for the E-parallel acceleration.