Frequency variations of solar radio zebras and their power-law spectra

0429504 - ASÚ 2015 RIV FR eng J - Journal Article
Karlický, Marian
Frequency variations of solar radio zebras and their power-law spectra.
Astronomy & Astrophysics. Roč. 561, January (2014), A34/1-A34/4. ISSN 0004-6361. E-ISSN 1432-0746
R&D Projects: GA ČR GAP209/12/0103
Grant - others:EU(XE) PIRSES-GA-2011-295272
Institutional support: RVO:67985815
Keywords : Sun * radio radiation * plasmas
Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics
Impact factor: 4.378, year: 2014

Power spectra of the frequency variations of zebras are computed to estimate the spectra of the plasma density variations in radio zebra sources. Methods: Frequency variations of zebra lines and the high-frequency boundary of the whole radio burst were determined with and without the frequency fitting. The computed time dependencies of these variations were analyzed with the Fourier method. First, we computed the variation spectrum of the high-frequency boundary of the whole radio burst, which is composed of several zebra patterns. This power spectrum has a power-law form with a power-law index -1.65. Then, we selected three well-defined zebra-lines in three different zebra patterns and computed the spectra of their frequency variations. The power-law indices in these cases are found to be in the interval between -1.61 and -1.75. Finally, assuming that the zebra-line frequency is generated on the upper-hybrid frequency and that the plasma frequency omegape is much higher than the electron-cyclotron frequency omegace, the Fourier power spectra are interpreted to be those of the electron plasma density in zebra radio sources.
Permanent Link: http://hdl.handle.net/11104/0234634