Solar Physics

, Volume 49, Issue 1, pp 117–140 | Cite as

Continuous injection model for hard X-ray correlated microwave bursts

  • Christian Mätzler
Article
Received:
Revised:

Abstract

Asymmetric magnetic field configurations in solar active regions hinder mildly relativistic electrons with magnetic moments suitable to produce microwave radiation from being trapped. Therefore the duration of stay of electrons in the microwave source region is much shorter (<0.2 s) than in the usually assumed trapping models. On this basis we construct a consistent model of hard X-ray correlated microwave bursts due to continuous injection of electrons into a pole field of an asymmetric magnetic loop (Figures 1 and 2). This resolves the discrepancy of the numbers of electrons needed to produce X-ray and radio emission.

We compute gyrosynchrotron spectra with the assumption of conservation of the magnetic moment M in the microwave source. The consequence is an anticorrelation between the low frequency power index a of the microwave spectrum and the power index γ of the hard X-ray spectrum. In fact during the flare of May 18, 1972 γ increases with time while a is decreasing, so that γ+a= constant. Furthermore, it is shown that electrons with energies below 100 keV contribute significantly to the microwave radiation; they determine the low frequency spectrum completely.

The model is able to explain the most often observed type C-spectra (Guidice and Castelli, 1975), but also flat spectra over one frequency decade.

Keywords

Microwave Flare Microwave Radiation Radio Emission Power Index 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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Copyright information

© D. Reidel Publishing Company 1976

Authors and Affiliations

  • Christian Mätzler
    • 1
  1. 1.NASA Goddard Space Flight Center, Code 660GreenbeltUSA

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