ISSN:
1573-093X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Direction finding measurements with the plasma wave experiments on the HAWKEYE 1 and IMP-8 satellites are used to find the source locations of type III solar radio bursts in elevation (geocentric solar ecliptic latitude) and azimuth (geocentric solar ecliptic longitude) in a frequency range from 31.1 kHz to 500 kHz. IMP-8 has its spin axis perpendicular to the ecliptic plane, hence by analyzing the spin modulation of the signals the location of the type III burst projected into the ecliptic can be found. HAWKEYE 1 has its spin axis nearly parallel to the ecliptic plane, hence the elevation of the source may also be determined. The trajectory of the electrons generating the burst, projected onto the ecliptic plane, follows an Archimedean spiral. Out of the ecliptic plane the trajectory is at a nearly constant heliographic latitude. The electrons originate from a region near a solar flare. With direction measurements of elevation and azimuth along with the modulation factor it is possible to determine the source size. Typical half angle source sizes range from ∼60° at 500 kHz to ∼40° at 56.2 kHz as viewed from the sun.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00149871
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