ULF Wave Absorption at Mercury
Authors: Eua-Hwa Kim, Jay R. Johnson, and Kyung-Dong Lee
Abstract:
The field line resonance at Mercury is expected to occur
when the ion‐ ion hybrid (IIH) and/or Alfvén resonance
conditions are satisfied. However, the relative efficiency of
wave energy absorption at these resonances has not been
studied in the context of Mercury’ s magnetosphere. To
understand the efficiency of wave absorption, we evaluate
absorption coefficients at the IIH and Alfvén resonances for
variable concentrations of sodium and azimuthal and fieldaligned
wave numbers in 1D multi‐ion plasmas. The results
show that wave absorption is much more efficient at the
IIH resonance than at the Alfvén resonance at Mercury. Our
results suggest that the mode conversion efficiency is sensitive
to the azimuthal and field aligned wave numbers as well
as heavy ion concentration ratio. Therefore, the radial profile
of field‐line resonances at Mercury can exhibit complex,
discontinuous structure.
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Submitted to: Geophysical Research Letter (June 2011)
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