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Ray tracing of broadband bursty radio emissions from Uranus
Author(s) -
Curran D. B.,
Menietti J. D.,
Wong H. K.
Publication year - 1990
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl017i002p00109
Subject(s) - physics , uranus , magnetic field , field line , plasma , broadband , astrophysics , emission spectrum , line (geometry) , computational physics , spectral line , optics , astronomy , planet , geometry , quantum mechanics , mathematics
To determine the source position of the broad‐band bursty emission, we traced rays of X‐mode emission from source positions along magnetic field lines with footprints that form a large grid centered approximately on the south magnetic pole of Uranus. We assumed the emission is just above the RX cutoff frequency, and we included sources only if the ratio of plasma to gyrofrequency was less than about 0.25. Contrary to the results of others who have assumed straight‐line propagation, we found, for large wave normal angles, source regions different from those producing b‐smooth emission, and along field lines with footprints in a relatively large area associated with the south magnetic pole. The emission which was observed prior to closest approach has a source along field lines that are distinct from those which generate emissions observed after closest approach. In order to understand these findings and the bursty nature of the emission we speculate the plasma distribution in the source region and/or the source mechanism is distinct from that which generates the b‐smooth emission.