Gyrosynchrotron Emission from Anisotropic Electron Distributions'

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Gyrosynchrotron Emission from Anisotropic
Electron Distributions.
G.D.Fleishman

• .

G.D.Fleishman, V.F.Melnikov, 2003, ApJ, 584, 1071
G.D.Fleishman, V.F.Melnikov, 2003, ApJ, 587, 823
G.D.Fleishman, D.E.Gary, G.M.Nita, 2003, ApJ,
593, 571
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PLAN of the TALK.
1.Introduction. 2.Low frequency spectral
structure. 3.Gyrosynchrotron continuum. 4.ECM
emission vs GS continuum. 5.Observational
evidence and applications. 6.Conclusions.
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THEORY (why pitch-angle anisotropy affects
optically thin GS spectrum?)
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Energy spectral Index of the Electrons
d5
Spectral Index of the Electrons, Estimated
from Radio spectrum
dr3.4
(dDM2.7)
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• Model Assumptions
• - Magnetic mirroring,
• Weak diffusion,
• Isotropic injection,
• Particle losses.

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Example 28 May 1993 flare (Courtesy by Tim
Bastian)
x
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Anisotropy
?
Instability
Isotropisation
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CONCLUSIONS

• 1.Pitch-angle anisotropy affects strongly GS
  emission.
• 2.There are ample evidence of the pitch-angle
  anisotropy in the microwave bursts.
• 3.The entire (through the loop) distribution of
  the trapped fast electrons is anisotropic in the
  spike-producing events.