Is the Linear Mode Conversion Theory viable for generating Kilometric Continuum?

S.A. Boardsen, J.L. Green, K. Hasmimoto, H. Matsumoto, D.L. Gallagher, P.A. Webb


Kilometric Continuum (KC) usually exhibits a complicated banded radiation
pattern observed in frequency time spectrograms. Can the number of bands, the
frequency range over which the bands are observed, and their time variation be
explained with Linear Mode Conversion Theory (LMCT) using realistic plasmapause
models and Extreme Ultraviolet (EUV) plasmaspheric observations? In this paper
we compare KC observations with simulated frequency emission bands based on LMCT
for a number of cases. In LMCT the allowed frequency range across the equatorial
plasmapause is restricted to frequencies much greater than the electron
cyclotron frequency (fce) and less than the maximum plasma frequency in this
region. Fce also determines the number of allowed bands in this range. Is the
observed frequency range and number of bands consistent with the predications of
LMCT? Can irregularities in the shape of plasmaspheric structures like notches
be observed in the time variations of KC emissions? We will investigate these
and other questions. Simulated radiation patterns will be generated by ray
tracing calculations in the L-O mode from the radio window at the near
equatorial plasmapause. The KC observations used in this study are from the
Plasma Wave Instrument on the Geotail spacecraft and from the Radio Plasma
Imager on the IMAGE spacecraft. The plasmasphere and plasmapause will be derived
either from plasmasphere simulations, from images by the EUV imager on the IMAGE
spacecraft, and by using empirical models. In situ plasma density measurements
from a number of spacecraft will also be used in order to reconstruct the
plasmasphere for these case studies.

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Spring Joint Assembly, American Geophysical Union, Baltimore, Maryland, U.S.A., 
23-26 May 2006