Earth Planets Space, Vol. 56 (No. 11), pp. e33-e36, 2004E-LETTER
D.-H. Lee1, K.-H. Kim1, R.E.Denton2, K.Takahashi3
1Department of Astronomy and Space Science, Kyung Hee University, Korea
2Department of Physics and Astronomy, Dartmouth College, USA
3The Johns Hopkins University Applied Physics Laboratory, USA
(Received June 19, 2004; Revised October 20, 2004; Accepted October 21, 2004)
We calculate the mode structure of magnetospheric MHD waves on a meridional plane. We have added the effect of ionospheric dissipation to the three-dimensional dipole field MHD model of Lee and Lysak (1999); this model allows a realistic Alfven speed profile for the plasmasphere and realistic boundary conditions at the outer boundaries that vary with respect to local time. Using power spectra and plots of spatial mode structure, we show that the two-dimensional transverse modes on the dipolar meridian are strongly affected by ionospheric damping, but the compressional modes are not. The location of field line resonances spreads wide as the damping increases, but the compressional mode structure remains stable.
Key words: MHD waves, magnetosphere, ionosphere, field line resonance.