IMAGE/MENA observations of ENA enhancements associated with increases in magnetospheric convection strength R M Skoug, M F Thomsen, H O Funsten, G D Reeves, M G Henderson (Los Alamos National Laboratory, MS D466, Los Alamos, NM 87545; 505-667-6594; rskoug@lanl.gov) C J Pollock, D J McComas (Southwest Research Institute, Instrumentation and Space Research Division, San Antonio, TX 78238) The Medium Energy Neutral Atom (MENA) imager on the IMAGE spacecraft measures magnetospheric neutral atoms from ~1-30 keV with ~4x4 degree angular resolution. The observed flux of neutral atoms is a convolution of the flux of energetic charged particles and the density of the neutral hydrogen exosphere. Enhanced neutral atom fluxes are thus observed both at times when the charged particle density is increased and at times when the charged particles are closer to the Earth and so encounter a higher neutral particle density. MENA detects enhancements in the flux of neutral atoms during storm and substorm times. MENA also detects such enhancements at other times, when no storm or substorm signatures are observed. These intervals correspond to times when the MPA instruments on the LANL geosynchronous satellites observe an increase in the upper cutoff energy of plasma sheet electrons. It is thought that this upper cutoff provides a measure of the strength of the convection electric field. The MENA observations support this idea, showing that magnetospheric charged particles are convected to near the Earth at times when the cutoff energy is increased. _______________ Presented at the Fall American Geophysical Union Meeting, San Francisco, CA., December 15-19, 2000