HR: 1330h
AN: SH42B-0508    [PDF]
TI: Coronal Radio Magnetography of Solar Active Region 8365
AU: Ryabov, B I
AF: Institute of Astronomy, Latvian University, Riga, LV-1586 Latvia
AU: Nindos, A
AF: Section of Astrogeophysics, Physics Department, University of Ioannina, Ioannina, GR- 45110 Greece
AU: Shibasaki, K
AF: Nobeyama Radio Observatory, Minamimaki, Nagano, 384-13 Japan
AU: Maksimov, V P
AF: Institute of Solar-Terrestrial Physics, PO Box 4026, Irkutsk, 664033 Russian Federation
AU: Lesovoi, S V
AF: Institute of Solar-Terrestrial Physics, PO Box 4026, Irkutsk, 664033 Russian Federation
AU: * Pevtsov, A A
EM: apevtsov@nso.edu
AF: National Solar Observatory, Sacramento Peak, Sunspot, NM 88349 United States
AB: Using the microwave radio observations with Siberian Solar Radio Telescope (SSRT) and Nobeyama Radio Heliograph (NoRH) we derived 2D coronal magnetograms of solar active region NOAA 8365. The circular polarization (CP) of radio source is modified, when the radiation passes through the overlying magnetic field transverse to the line-of-sight. This change in CP was used to study the properties of coronal fields. We employed the known theory of wave-mode coupling in quasi-transverse (QT) region to evaluate the distribution of the field strength at the level of transformation of 5.2 cm radiation (SSRT, field strength $\sim$ 10-30 G) and 1.76 cm (NoRH, $\sim$ 50-110 G). The magnetic field strength was derived under the assumption N~L$_\alpha$ = 10$^{18}$ cm$^{-2}$, where N is electron density and L$_\alpha$ is the scale of coronal field divergence along line-of-sight. The height of QT-region (H$_{QTR}$) was estimated using force free field extrapolations, H$_{QRT}$ = 6.3 $\times$ 10$^9$ cm (2.3 $\times$ 10$^9$ cm) for 20 G (85 G). We then compared the coronal radio magnetograms and the force free field extrapolation of photospheric magnetic field, and we found close similarity between them on large spatial scale.
DE: 7509 Corona
DE: 7524 Magnetic fields
DE: 7534 Radio emissions
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting