Flare-plasma diagnostics from millisecond pulsations of the solar radio emission

V. F. Melnikov, Gregory Fleishman, Q. J. Fu, G. L. Huang

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Two solar radio bursts exhibiting narrow-band millisecond pulsations in intensity and polarization are analyzed. There were considerable time delays between the left- and right-circularly polarized components of the radio emission. The observed oscillations of the degree of polarization are due to the different group velocities of the ordinary and extraordinary modes in their propagation from the source to the observer; the frequency dependence of the delay is in excellent agreement with the theoretically calculated group delay in a magnetoactive plasma. It unambiguously follows that the pulsed radio emission is generated near the double upper hybrid frequency by the nonlinear plasma mechanism, since the source emission has a low degree of polarization. In addition to dispersion effects, a Fourier analysis also reveals effects associated with the source inhomogeneity. We detected a frequency drift of pulsations (autodelays) with different signs for different polarization components. This drift suggests that, apart from the dispersion effects, there are also the effects related to inhomogeneity of the radio source. It is shown, in particular, that the upper hybrid modes (generating the radio emission) are unstable in regions with enhanced gradients of the plasma density and/or magnetic field.

Original languageEnglish (US)
Pages (from-to)497-514
Number of pages18
JournalAstronomy Reports
Volume46
Issue number6
DOIs
StatePublished - 2002

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint Dive into the research topics of 'Flare-plasma diagnostics from millisecond pulsations of the solar radio emission'. Together they form a unique fingerprint.

Cite this