Whistler Mode Experiments using the Radio Plasma Imager on-board the IMAGE satellite Maria Salvati Space, Telecommunications and Radioscience Laboratory Stanford University NASA Advisor: Dr. Robert Benson Faculty Advisors: Dr. Umran Inan & Dr. Donald Carpenter The Radio Plasma Imager (RPI) instrument currently operating on the IMAGE satellite performs radar remote sensing measurements of plasma density structures in the Earth's magnetosphere using a radio wave sounder in the frequency range of 3 kHz to 3 MHz. Within the plasmasphere and at low altitudes over the southern polar regions, the lower frequencies of RPI can be used for transmission and reception in the whistler mode. This mode exists for frequencies lower than the smaller of the electron plasma and gyrofrequency. This paper discusses three types of whistler mode experiments performed with RPI. The first is a study of whistler mode echoes returning to the IMAGE satellite. Whistler mode waves propagating in the magnetosphere can be reflected due to magnetospheric reflection, which occurs where the plasma's lower hybrid resonance frequency becomes equal to the transmitted frequency, or by specular reflection, which occurs at the lower ionosphere-Earth boundary due to the sharp refractive index change. In the second experiment, several ground stations in the Antarctic will attempt to receive pulses transmitted by RPI in the whistler mode that have penetrated the ionosphere. Study of signal penetration could provide new understanding of the conditions under which natural plasma emissions are received on the ground. The third whistler mode experiment will be a joint campaign between the IMAGE satellite and the High-frequency Active Auroral Research Program (HAARP). The HAARP ionospheric heater will be used to generate very low frequency waves by artificial modulation of the auroral electrojet currents. RPI will be placed in receive mode to observe the stimulated VLF emissions. ______________ Presented at the GSFC, Graduate Student Research Program (GSRP) Symposium, September 21, 2000.