Multiple wavelength observations of flaring active regions
Observations of flaring active regions with the Very Large Array (at 6 cm and 20 cm wavelengths) and the Westerbork Synthesis Radio Telescope (at 6 cm wavelength) are presented and these are compared with photospheric magnetograms and with H-alpha and offband H-alpha photographs. The 6 cm radiation of these active regions marks the legs of dipolar loops which have their footpoints in lower-lying sunspots and this radiation lies above sunspot umbrae in coronal regions. Circularly polarized horseshoe structures at 6 cm ring the sunspot umbrae and the high degree of circular polarization (95 percent) of the horseshoes can be attributed to gyroresonant emission above sunspot penumbrae. Looplike structures are exhibited in the 20 cm radiation of these active regions which extend across regions of opposite magnetic polarity in the underlying photosphere. The 20 cm loops were found to be the radio wavelength counterparts of the X-ray coronal loops. Calculations indicate semilengths of 5 x 10 to the 9th cm, maximum electron temperatures of 3 x 10 to the 6th K, and electron densities of 10 to the 9th/cu cm for the 20 cm bremsstrahlung. A total of eight solar bursts were observed at 6 cm or 20 cm wavelength with second-of-arc angular resolution.
- Research Organization:
- Tufts Univ., Medford, MA
- OSTI ID:
- 6448841
- Report Number(s):
- CONF-820582-; TRN: 84-022259
- Journal Information:
- Adv. Space Res.; (United States), Vol. 2; Conference: 24. COSPAR meeting (Committee on Space Research), Ottawa, Canada, 17 May 1982
- Country of Publication:
- United States
- Language:
- English
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