Storm enhanced electron density in the polar cap region observed by the Radio Plasma Imager 
on IMAGE

Nsumei, P., Song, P., Reinisch, B.W., Huang, X. 


The radio plasma imager (RPI) on the IMAGE satellite uses the radio sounding technique to
measure both the insitu and remote electron densities in the magnetosphere. Insitu, or 
local, electron densities are derived from the local plasma resonances stimulated by RPI 
transmitted signals while the remote densities are obtained from the observed R-X mode echo 
traces using an inversion technique. Analysis of RPI observations before, during and after 
a geomagnetic storm shows a greatly enhanced electron density during the main phase over 
the polar cap at radial distances up to 5.3 RE, invariant latitude above 80 degrees and 
magnetic local time between 2000 and midnight. In this report a case study will be 
presented and qualitative and quantitative assessment of the magnitude of electron density 
enhancement will be discussed. 
		   
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Fall 2002 Meeting of the American Geophysical Union
San Francisco, CA, USA, 6-10 December 2002