Magnetospheric cusp observations using the image satellite radio plasma imager

Abstract

On March 25, 2000, the Imager for Magnetopause-to-Auroral Global Exploration (IMAGE) satellite mission was launched with the Radio Plasma Imager (RPI) radio sounder instrument onboard. Once deployed, the RPI began remote detection of regions of differing plasma densities via the reflection of transmitted radio waves. One of these regions is the magnetospheric polar cusp, which contains solar wind particles injected onto magnetospheric field lines by the process of dayside reconnection. Using data from the first month of RPI active sounding operation, a candidate cusp plasma echo return was analyzed to confirm that these signatures are in fact due to cusp plasmas. Associated in situ measurements also taken by the RPI instrument, as well as theoretical ray traces within an idealized model magnetosphere, strongly indicate that the RPI can and does remotely observe particle densities within the cusp region.