A role of cosmic rays in generation of radio and optical radiation by plasma mechanisms

I. N. Toptygin, G. D. Fleishman

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The radiation of ultrarelativistic particles is examined in a quasi-uniform magnetic field superimposed by a wide spectrum of magnetic, electric, and electron density inhomogeneities created in a turbulent plasma. The radiation spectrum from a particle of a given energy is shown to acquire a high-frequency power-law tail with the same spectral index as the index ν of small-scale turbulence. For a power-law spectrum of ultrarelativistic electrons, d N(ℰ)/dℰ ~ ℰ, with a cut-off at some energy ℰmax, the radiation spectrum consists of a few power-law ranges; the radiation intensity may suffer jumps at frequencies which separate these ranges. In the high-frequency range the spectral index ν is determined by small-scale magnetic and electric fields. At intermediate frequencies the main contribution comes from the synchrotron radiation in a large-scale field; the radiation spectrum has an index α=(ζ-1)/2. The same index may be produced by large-scale Langmuir waves. At lower frequencies the radiation spectrum increases owing to the transition radiation caused by electron density fluctuations; in this case the spectral index is equal to ζ+1-ν. The possibility of diagnostics of high-frequency cosmic plasma turbulence from radiation of high-energy particles is discussed. It is shown that the proposed theory may explain some features in the spectra of several cosmic objects.

Original languageEnglish (US)
Pages (from-to)213-248
Number of pages36
JournalAstrophysics and Space Science
Issue number2
StatePublished - Apr 1987
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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