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Spectral observations of active region sources with RATAN-600 and WSRTWe present spectral observations of neutral line and sunspot associated sources obtained with the RATAN-600 radio telescope and the WSRT in the wavelength range of 2 to 6 cm. Sources associated with large sunspots have flat spectra, while neutral line sources have very steep spectra. In the case of a large spot we estimated the magnetic field to be at least 2700 G at the base of the transition region and 1800 G in the low corona. We consider possible interpretations of the radio emission above the neutral lines. Gyroresonance emission at the fourth harmonic is inadequate, whereas emission from a small population of nonthermal electrons (total number 10 exp 30 to 10 exp 31) with a delta = 3 power law distribution seems to be sufficient.
Document ID
19940036475
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Alissandrakis, C. E.
(Athens Univ. Greece)
Gel'frejkh, G. B.
(NASA Headquarters Washington, DC United States)
Borovik, V. N.
(Main Astronomical Observatory Pulkovo, Russia)
Korzhavin, A. N.
(NASA Headquarters Washington, DC United States)
Bogod, V. M.
(Special Astrophysical Observatory Pulkovo, Russia)
Nindos, A.
(Athens Univ. Greece)
Kundu, M. R.
(Maryland Univ. College Park, United States)
Date Acquired
August 16, 2013
Publication Date
March 1, 1993
Publication Information
Publication: Astronomy and Astrophysics
Volume: 270
Issue: 2-Jan
ISSN: 0004-6361
Subject Category
Solar Physics
Accession Number
94A13130
Funding Number(s)
CONTRACT_GRANT: NSF ATM-90-19893
CONTRACT_GRANT: NAGW-1541
Distribution Limits
Public
Copyright
Other

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