HR: 0800h
AN: SM21A-0454    [Abstracts]
TI: Electromagnetic Ion Cyclotron Waves as a Diagnostic for Heavy Ion Mass Density
AU: * Johnson, J R
EM: jrj@pppl.gov
AF: Princeton University, Plasma Physics Laboratory PO Box 451, Princeton, NJ 08543 United States
AU: Cheng, C Z
EM: fcheng@pppl.gov
AF: Princeton University, Plasma Physics Laboratory PO Box 451, Princeton, NJ 08543 United States
AB: Conjugate observations of electromagnetic ion cyclotron (EMIC) waves by satellites, rockets, and ground based magnetometers have the potential to identify mass concentrations along magnetic field lines. EMIC wave tend to propagate along magnetic field lines so measurements made in conjunction along a field line can be used to infer conditions along that field line. Moreover, because wave propagation through heavy ion resonances is strongly dependent on the heavy ion concentration near the resonance location, it is possible to deduce localized information about the heavy ion mass concentration from a comparison between wave measurements and theoretical calculations of wave propagation that include wave dissipation near the heavy ion resonances. When a spectrum of wave measurements is available, the spread of frequency maps to an altitude range along the field line for which mass concentrations can be inferred. Because wave measurements are available in the range 1-200 Hz, it is possible to induce information about mass concentration from the topside ionosphere to beyond geosynchronous orbit. To obtain accurate wave solutions we solve a set of electromagnetic wave equations relevant to wave propagation through the magnetosphere and topside ionosphere. These solutions include the possibility of mode conversion among the propagating wave modes, dissipation at the cyclotron resonance, and collisional dissipation and reflection of the wave in the ionosphere. The model predicts observables such as Poynting flux, wave polarization, and wave amplitude that constrain the heavy ion concentrations along the field line. The wave solutions could also be the basis for a control experiment by emitting EMIC waves from a satellite and detecting them using other satellites or ground based instruments.
UR: http://w3.pppl.gov/$\sim$jrj/icw.html
DE: 7867 Wave/particle interactions
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2487 Wave propagation (6934)
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting