Physics
Scientific paper
Dec 2002
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002agufmsm52a0530l&link_type=abstract
American Geophysical Union, Fall Meeting 2002, abstract #SM52A-0530
Physics
2431 Ionosphere/Magnetosphere Interactions (2736), 2487 Wave Propagation (6934), 2753 Numerical Modeling, 2768 Plasmasphere, 2788 Storms And Substorms
Scientific paper
Pi2 pulsations observed in the plasmasphere indicate the presence of the toroidal components, radial electric field and azimuthal magnetic field, of field line oscillations. According to an Akebono spacecraft observation made at 24-40 degree magnetic latitude, the oscillations carried a large Poynting flux directed toward the ionosphere and it has been suggested that the cavity mode oscillation is quickly damped by this loss mechanism [Osaki et al., JGR, 17,605, 1998]. However, a recent Polar observation at 10-14 degree magnetic latitude showed a small Poynting flux [Keiling et al., JGR, page 25,8981, 2001]. These conflicting observations motivated us to run the simulation code developed in a previous study of plasmaspheric Pi2 pulsations [Lee and Lysak, 1999]. The simulation incorporated a nightside impulsive source, a plasmapause density gradient, energy loss from the magnetopause, and ionospheric damping. The cross phase between the electric and magnetic fields of the toroidal mode was near 90 degrees near the equator but it became smaller as latitude increased. This is consistent with the behavior of the Poynting flux observed from spacecraft. The cross phase changes because the electric field is required to gradually become in phase with the magnetic field as the ionosphere approaches. The simulation also produced compressional poloidal oscillations exhibiting the properties of virtual plasmaspheric resonance (cavity mode). The decay time scale differed between the toroidal and poloidal modes, and we conclude that the duration of the virtual resonance is not much affected by the ionospheric damping of the toroidal mode.
Lee Daehee
Takahashi Keitaro
No associations
LandOfFree
Simulation Study of Ionospheric Damping of Pi2 Pulsations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Simulation Study of Ionospheric Damping of Pi2 Pulsations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Simulation Study of Ionospheric Damping of Pi2 Pulsations will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1439025