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VLA (Very Large Array) observations of solar active regions at closely spaced frequencies. Evidence for thermal cyclotron line emission

Technical Report ·
OSTI ID:5684566
VLA observations of a solar-active region at 10 closely spaced frequencies between 1440 and 1720 MHz are presented. The synthesis maps show, on two successive days, significant changes in the brightness temperature within this narrow frequency range. It is shown that these changes cannot be due to either thermal bremsstrahlung or gyroresonance emission from a coronal loop in which the temperature, density, or magnetic field varies monotonically with height. Instead, the brighness spectrum is attributed to cyclotron line emission from a narrow layer where the temperature is elevated above the surrounding part of the loop.
Research Organization:
Tufts Univ., Medford, MA (USA). Dept. of Physics and Astronomy
OSTI ID:
5684566
Report Number(s):
AD-A-166118/0/XAB
Country of Publication:
United States
Language:
English