Polarization of Field Aligned Propogating Echoes in the Plasmasphere using the 
Radio Plasma Imager

G. S. Sales, B. W. Reinisch, X. Huang, I. A. Galkin 
Center for Atmospheric Research, University of Massachusetts Lowell, 
600 Suffolk Street, Lowell, MA 01854, USA

J.L. Green
NASA Goddard Space Flight Center, Greenbelt, MD, USA


Analysis of radio plasma imager (RP plasmagrams show that echo signals often 
propagate along the earthÕs magnetic field to both hemispheres. Using measured 
signals on RPIÕs orthogonal antenna system makes it possible to determine not 
only the arrival direction but also the polarization characteristics of the 
arriving wave. The measured arrival-angles are nearly parallel or anti-parallel 
to the local magnetic field. Based on plasmagram trace inversions, it has been 
concluded that these echoes are X mode waves. This result is confirmed here; 
all analyzed traces were X-mode, though the observed polarization ellipses were 
often not circular. 

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To be presented at the 27th General Assembly of International Union of 
Radio Science (URSI), Maastricht, The Netherlands, August 17-24, 2002.