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Title: Microwave imaging of a solar limb flare: Comparison of spectra and spatial geometry with hard X-rays

Journal Article · · Astrophys. J.; (United States)
DOI:https://doi.org/10.1086/163769· OSTI ID:5802270

We have mapped a solar limb flare using the VLA at 6 cm wavelength with 8'' spatial resolution, simultaneously with hard X-ray spectral and spatial observations with the Solar Maximum Mission satellite. Microwave flux records from 2.8-19.6 Ghz have enabled us to determine the burst spectrum, which has a maximum at 10 GHz. The rising side of each of three microwave subbursts within the flare were simultaneous to < or approx. =1 s, with hard X-ray rises toward maxima. The flux spectrum and area of the burst sources were used to determine the number of electrons producing gyrosynchrotron emission (approx.1 x 10/sup 33/), the strength of the magnetic field (approx.550 G), and the energy distribution of gyrosynchrotron-emitting electrons (approx.E/sup -3/). Applying the thick target model to the hard X-ray flux spectrum, the number of high energy (E>25 keV) electrons responsible for the X-ray bursts was found to be Nroughly-equal110/sup 36/, and the electron energy distribution was approx.E/sup -5/, significantly different from the parameters derived from the microwave observations.

Research Organization:
Astronomy Program, University of Maryland
OSTI ID:
5802270
Journal Information:
Astrophys. J.; (United States), Vol. 299:2
Country of Publication:
United States
Language:
English