Decimetric gyrosynchrotron emission during a solar flare
A decimetric, microwave, and hard X-ray burst was observed during a solar flare in which the radio spectrum below peak flux fits an f+2 power law over more than a decade in frequency. The spectrum is interpreted to mean that the radio emission originated in a homogeneous, thermal, gyrosynchrotron source. This is the first time that gyrosynchrotron radiation has been identified at such low decimetric frequencies (900-998) MHz). The radio emission was cotemporal with the largest single hard X-ray spike burst ever reported. The spectrum of the hard X-ray burst can be well represented by a thermal bremsstrahlung function over the energy range from 30 to 463 keV at the time of maximum flux. The temporal coincidence and thermal form of both the X-ray and radio spectra suggest a common source electron distribution. The unusual low-frequency extent of the single-temperature thermal radio spectrum and its association with the hard X-ray burst imply that the source had an area approx. 10(18) sq cm a temperature approx 5x10(8) K, an electron density approx. 7.10(9) cu cm and a magnetic field of approx. 120 G. H(alpha) and 400-800 MHz evidence suggest that a loop structure of length 10,000 km existed in the flare active region which could have been the common, thermal source of the observed impulsive emissions.
- Research Organization:
- National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center
- OSTI ID:
- 6593501
- Report Number(s):
- N-84-16107; NASA-TM-85123
- Country of Publication:
- United States
- Language:
- English
Similar Records
THE SOLAR DECIMETRIC SPIKE BURST OF 2006 DECEMBER 6: POSSIBLE EVIDENCE FOR FIELD-ALIGNED POTENTIAL DROPS IN POST-ERUPTION LOOPS
Gyrosynchrotron emission from quasi-thermal electrons and applications to solar flares