Survey analysis of chorus intensity at Saturn

Author
Keywords
Abstract
In order to conduct theoretical studies or modeling of pitch angle scattering of electrons by whistler mode chorus emission at Saturn, a knowledge of chorus occurrence and magnetic intensity levels, PB, as well as the distribution of PB relative to frequency and spatial parameters is essential. In this paper an extensive survey of whistler mode magnetic intensity levels at Saturn is carried out, and Gaussian fits of PB are performed. We fit the spectrum of wave magnetic intensity between the lower hybrid frequency and fceq/2 and for frequencies in the interval fceq/2 < f < 0.9 fceq, where fceq is the cyclotron frequency mapped to the equator. Saturn chorus is observed over most local times, but is dominant on the nightside in the range of 4.5 < L <7.5, with minimum power at the equator and peak power in the range of 5\textdegree < λ < 10\textdegree. Saturn wave magnetic intensity averaged in frequency bins peaks in the range of 10-5 < PB < 10-4 nT2 for 0.4 < β < 0.5 (β = f/fceq). Gaussian fits of PB with frequency and latitude are obtained for lower band chorus. Plasma injection regions are occasionally encountered with significant chorus power levels. Upper band chorus is seen almost exclusively within plasma injection regions, and the number of events is very limited, but when present, the average levels of PB can be higher than the lower band chorus. The overall magnetic intensity contribution of the upper band, however, is insignificant relative to the lower band.
Year of Publication
2014
Journal
Journal of Geophysical Research: Space Physics
Volume
119
Number of Pages
8415-8425
Date Published
10/2014
URL
http://doi.wiley.com/10.1002/jgra.v119.10http://doi.wiley.com/10.1002/2014JA020523
DOI
10.1002/jgra.v119.1010.1002/2014JA020523