EDP Sciences
Free access
Volume 392, Number 3, September IV 2002
Page(s) 1089 - 1094
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20020980

A&A 392, 1089-1094 (2002)
DOI: 10.1051/0004-6361:20020980

Polarization changes in solar radio emission caused by scattering from high-frequency plasma turbulence

V. G. Ledenev1, V. V. Tirsky2, V. M. Tomozov1 and P. Zlobec3

1  Institute of Solar-Terrestrial Physics, Irkutsk, 664033, PO Box 4026, Russia
2  Institute of Laser Physics, Irkutsk Branch, Russia
3  Trieste Astronomical Observatory, via G. B. Tiepolo 11, 34131 Trieste, Italy

(Received 29 March 2002 / Accepted 13 May 2002)

This paper deals with the scattering of electromagnetic radiation during propagation through a plasma layer with developed Langmuir turbulence. The ordinary component is slightly lowered, while the extraordinary component undergoes the most effective scattering. This leads to a change in the polarization characteristics of the original radiation, namely: the extraordinarily polarized emission can undergo a substantial decrease and even the polarization sign can be changed. As a consequence the radiation increases its polarization degree in the ordinary mode.

We performed calculations of the polarization of the radio emission propagating through a layer of turbulent plasma and examined the complex event that occurred on July 14, 2000; specifically, this event showed long-lasting emissions and the polarization varied both in time and in frequency range. Assuming that the variation of the polarization degree during the lifetime of the phenomenon is determined by the scattering from Langmuir turbulence, we obtained an estimate of the level of turbulence and of the magnetic field intensity in the emission region.

Key words: Sun: activity; flares; particle emission; radio radiation

Offprint request: V. G. Ledenev, leden@iszf.irk.ru

SIMBAD Objects in preparation

© ESO 2002