Faraday-rotation fluctuations from radio-sounding measurements of the circumsolar plasma using polarized signals from the HELIOS-1 and HELIOS-2 space probes
| Autor: | I. V. Chashei, L. N. Samoznaev, A. I. Efimov, Martin Paetzold, Michael K. Bird, A. I. Rogashkova, L. A. Lukanina |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Astronomy Reports. 59:313-326 |
| ISSN: | 1562-6881 1063-7729 |
| DOI: | 10.1134/s1063772915040022 |
| Popis: | Fluctuations in the Faraday rotation of the plane of polarization of S-band (2.3 GHz) radio signals transmitted through the solar corona by the HELIOS-1 AND HELIOS-2 space probes are analyzed. Simultaneous measurements of the Faraday-rotation fluctuations at the Goldstone and Canberra stations have yielded estimates of the velocity of perturbations of the magnetic field in the circumsolar plasma at heliocentric distances of three to six solar radii. The velocity of these perturbations is a combination of the Alfven and solar-wind speeds. Temporal spectra of the Faraday-rotation fluctuations are obtained based on a large volume of observational data obtained in various years in four cycles of radio-sounding experiments. Filtration of the input data using spectral, correlation, and wavelet analyses shows that trains of quasi-periodic oscillations of the magnetic field with various amplitudes and periods from 2 to 160 min are regularly present in the Faraday-rotation fluctuations. This quasi-periodic character of these perturbations supports their connection with Alfven waves propagating in the circumsolar plasma. |
| Databáze: | OpenAIRE |
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