Guided Echoes in the Magnetosphere: Observations by Radio Plasma Imager on IMAGE Fung, S.F., R.F. Benson, D.L. Carpenter, J.L. Green, V. Jayanti, I.A. Galkan, and B.W. Reinisch Long-range, discrete, radio echo traces observed in the magnetosphere by the Radio Plasma Imager (RPI) on IMAGE have been interpreted as guided radio signals along geomagnetic field lines. During passages of the plasmapause and near-equatorial plasmaspohere by IMAGE, multiple echo traces are often observed resulting from guided echoes reflected successively between conjugate hemispheres. Single traces seen far beyond the plasmapause at high latitudes are attibuted to guided echoes from only the local hemisphere in the polar region. In this case the field lines are either open, or closed but too long to maintain the signal-guiding conditions or to allow the conjugate signals to return within the instrument listening time. In this paper we present examples of guided echoes observed by RPI at altitudes of a few Earth radii. If the guided echoes in different magnetospheric plasma regimes are all caused by field-aligned irregularities, then such plasma irregularities must be more pervasive than previously recognized. _______________ Submitted to Geophys. Res. Letts., May, 2002