HR: 0830h
AN: SM51C-0542    [PDF]
TI: Investigating the Properties of Field-Line Resonances in the Inner Magnetosphere Using Independent Techniques
AU: * Menk, F W
EM: fred.menk@physics.org
AF: University of Newcastle, School of Mathematics and Physical Science, University Drive, Callaghan, NSW 2308 Australia
AU: Clilverd, M A
EM: MACL@bas.ac.uk
AF: British Antarctic Survey, Madingley Road, Cambridge, CB3 0ET United Kingdom
AB: This paper outlines a new experiment that simultaneously monitors ULF field line resonances and VLF whistler-mode waves propagating in the same L=2.5 duct. Closely-spaced magnetometers located on the Antarctic peninsula and in the SAMNET-BGS array provide measurements of the local field line eigenfrequency. This depends on the mass density near the field line apex, although the magnetometer spectra also contain contributions from non-field guided fast mode waves. VLF signals from transmitters in the US propagate in field-aligned ducts and are received near the duct footprint, by receivers co-located with the Antarctic peninsula magnetometers. Group delay of the VLF transmissions provides a measurement of the electron density. The Doppler shift of the ducted VLF signals is also measured and often shows oscillatory features that relate to radial motions of the duct. These motions are strongly correlated with Pc3-4 ULF pulsations recorded by the co-located magnetometers. We examine power and phase spectra for specific examples and show that the VLF Doppler observations provide direct information on properties of the ULF waves, including the electric field and wave mode. We also examine a case where several VLF ducts are simultaneously located within the field of view of the ULF experiment. Related issues include the identification of harmonic oscillations in the spectra, and the effect of the ionospheric conductivity on the standing ULF oscillations.
DE: 2730 Magnetosphere--inner
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2768 Plasmasphere
DE: 2772 Plasma waves and instabilities
DE: 6969 Remote sensing
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting