Microwave emission from steady and moving sunspotsForce-free extrapolations of photospheric magnetic field observations from Marshall Space Flight Center have been used to compute the total intensity and circular polarizaton of sunspot associated emission from active region 2502 in the period June 13 to 15, 1980. The computed maps were compared to high resolution observations of the same active region obtained with the Westerbork Synthesis Radio Telescope. The most interesting aspect of the active region was the development of a new spot between the preceding and the following spots on June 14, which subsequently merged with the preceding with the preceding spot. The new spot was associated with enhanced microwave emission with a peak brightness temperature in excess of 4 x 10 to the 6th K. It is shown that unrealistic values of the conductive flux are required for the interpretation of the emission of the new sunspot in terms of thermal processes. It is suggested that this source is due to gyrosynchrotron radiation from mildly relativistic electrons accelerated by resistive instabilities in the evolving magnetic field.
Document ID
19890045128
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Alissandrakis, C. E. (Athens, University Greece)
Chiuderi Drago, F. (Paris Observatoire, Meudon, France)
Hagyard, M. J. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1987
Subject Category
Solar Physics
Meeting Information
Meeting: European Regional Astronomy Meeting of the IAU