skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Decimetric gyrosynchrotron emission during a solar flare

Abstract

A decimetric, microwave, and hard X-ray burst has been observed during a solar flare in which the radio spectrum below peak plux fits an f/sup +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. Thiis 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 reportd. 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 th single-temperature thermal radio spectrum and its association with the hard X-ray burst imply that the source had an area approx.10/sup 18/ cm/sup 2/, a temperature approx.5 x 10/sup 8/ K, an electron density < or =7 x 10/sup 9/ cm/sup -3/, and a magnetic fiel of approx.120 gauss. H..cap alpha.. and 400--800 MHz evidence suggest that a loop structuremore » of length > or =10,000 km existed in the flare active region which could have been the common, thermal source of the observed impulsive emissions.« less

Authors:
; ;
Publication Date:
Research Org.:
Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina
OSTI Identifier:
6196233
Resource Type:
Journal Article
Journal Name:
Astrophys. J.; (United States)
Additional Journal Information:
Journal Volume: 280:2
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; SOLAR FLARES; RADIOWAVE RADIATION; SYNCHROTRON RADIATION; SUN; SOLAR X-RAY BURSTS; HARD X RADIATION; MHZ RANGE 100-1000; BREMSSTRAHLUNG; ELECTROMAGNETIC RADIATION; FREQUENCY RANGE; IONIZING RADIATIONS; MAIN SEQUENCE STARS; MHZ RANGE; RADIATIONS; SOLAR ACTIVITY; STARS; X RADIATION; 640104* - Astrophysics & Cosmology- Solar Phenomena

Citation Formats

Batchelor, D A, Benz, A O, and Wiehl, H J. Decimetric gyrosynchrotron emission during a solar flare. United States: N. p., 1984. Web. doi:10.1086/162062.
Batchelor, D A, Benz, A O, & Wiehl, H J. Decimetric gyrosynchrotron emission during a solar flare. United States. https://doi.org/10.1086/162062
Batchelor, D A, Benz, A O, and Wiehl, H J. 1984. "Decimetric gyrosynchrotron emission during a solar flare". United States. https://doi.org/10.1086/162062.
@article{osti_6196233,
title = {Decimetric gyrosynchrotron emission during a solar flare},
author = {Batchelor, D A and Benz, A O and Wiehl, H J},
abstractNote = {A decimetric, microwave, and hard X-ray burst has been observed during a solar flare in which the radio spectrum below peak plux fits an f/sup +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. Thiis 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 reportd. 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 th single-temperature thermal radio spectrum and its association with the hard X-ray burst imply that the source had an area approx.10/sup 18/ cm/sup 2/, a temperature approx.5 x 10/sup 8/ K, an electron density < or =7 x 10/sup 9/ cm/sup -3/, and a magnetic fiel of approx.120 gauss. H..cap alpha.. and 400--800 MHz evidence suggest that a loop structure of length > or =10,000 km existed in the flare active region which could have been the common, thermal source of the observed impulsive emissions.},
doi = {10.1086/162062},
url = {https://www.osti.gov/biblio/6196233}, journal = {Astrophys. J.; (United States)},
number = ,
volume = 280:2,
place = {United States},
year = {Tue May 15 00:00:00 EDT 1984},
month = {Tue May 15 00:00:00 EDT 1984}
}