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Decay time of type III solar bursts observed at kilometric wavelengths

✍ Scribed by Hector Alvarez; F. T. Haddock

Publisher
Springer
Year
1973
Tongue
English
Weight
412 KB
Volume
30
Category
Article
ISSN
0038-0938

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✦ Synopsis

Type llI bursts were observed between 3.5 MHz and 50 kHz by the University of Michigan radio astronomy experiment aboard the OGO-5 satellite.

Decay times were measured and then combined with published data ranging up to about 200 MHz. The observed decay times increase with decreasing frequency but at a rate considerably slower than that expected from electron-proton Coulomb collisions. At 50 kHz values differ by about a factor of 100. Using Hartle and Sturrock's solar wind model, Coulomb collisional frequencies were computed and compared with the apparent collisional frequencies deduced from the observations. It was found that the ratio of observed to computed values varies with heliocentric distance according to an inverse 0.71 power. This is similar to an ad hoc function used by Wolff, Brandt, and Southwick to increase the electron-proton collisional energy exchange and make the solar wind theory agree with the measurements of electron and proton temperature near the Earth. These results may provide a clue about the nature of the non-collisional plasma wave damping process responsible for the short duration of type III bursts.

πŸ“œ SIMILAR VOLUMES

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