Diagnostics of magnetospheric electron density and ion composition using whistler mode sounding data from the image satellite

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Author
Proddaturi, Radha Krishna
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URI
http://hdl.handle.net/11122/5724
Abstract
This thesis reports the observations of the Magnetospherically Reflected (MR) Whistler Mode (WM) echoes on the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite. These observations and interpretations were first reported in Sonwalkar et at. [2006]. MR-WM echoes were observed when RPI (Radio Plasma Imager) onboard the IMAGE satellite transmitted 3.2 ms pulses in the 6 kHz to 63 kHz frequency band. These echoes occurred at frequencies less than ~12 kHz with time delays ranging from 40 ms to 130 ms. MR-WM echoes were recorded when the satellite was at altitudes ranging from 700 km to 4000 km, geomagnetic latitudes from -30° to 50°, and magnetic local times 3 to 17. Ray tracing simulations confirmed that MR- WM echoes are a result of WM waves propagating along the geomagnetic field line and reflecting at an altitude where local flh [almost equal] f, where flh is the lower hybrid frequency and f is the wave frequency. In this interpretation, the lower and upper cutoff frequencies of the MR- WM echoes are equal to the flh at the satellite and the maximum flh along the geomagnetic field line passing through the satellite, respectively. These echoes were frequently accompanied by discrete WM echoes at frequencies greater than the maximum frequency of the MR- WM echoes. By matching the measured dispersions of the MR- WM and discrete WM echoes with that calculated from ray tracing simulations, remote estimates of electron density and ion effective mass were obtained along the geomagnetic field line passing through the satellite.
Description
Thesis (M.S.) University of Alaska Fairbanks, 2007
Table of Contents
1. Introduction -- 2. Experiment description -- 2.1. The IMAGE satellite orbit -- 2.2. Data analysis tools -- 3. Geomagnetic field model, cold plasma density model -- 3.1. The geomagnetic field model -- 3.2. The cold plasma density model -- 4. Analysis tools -- 4.1. Free space mode wave ray tracing program -- 5. Plasma diagnostics using multi-mode sounding of the magnetosphere -- 5.1. Interpretation of multi-mode echoes observed on 27 July 2003 -- 5.2. The procedure for estimating the electron density model from the ray tracing analysis of the multi-mode case -- 5.2.1. Estimation of the plasmapause location -- 5.3. Ray tracing analysis -- 5.3.1. Building a reference 'Cyan electron density' model -- 5.3.2. Ray tracing analysis of the discrete WM echo -- 5.3.3. ZM echo constraints on the electron density model -- 5.3.4. Fast ZM echo ray tracing analysis, estimated 'Green electron density' model -- 5.3.5. Discrete WM echo ray tracing analysis using the Green electron density model, estimated 'Red electron density' model -- 5.3.6. Comparison of the Cyan, Green, and Red electron density models estimated from the ray tracing analysis of the discrete WM and fast ZM echoes -- 5.3.7. Ray tracing analysis of the LO mode echo, estimated 'Blue electron density' model -- 5.3.8. Ray tracing analysis of the RX mode echo, estimated 'Brown electron density' model -- 5.3.9. Summary of the estimated electron density models from the ray tracing analysis of the multi-mode case -- 6. Magnetospherically reflected (MR) Whistler mode (WM) echoes -- 7. Summary, conclusions, and suggestions for the future work -- References -- Appendices.
Date
2007-08
Type
Thesis
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