Energetic neutral atom imaging of Mercury's magnetosphere 3. Simulated images and instrument requirements

The paper presents simulations of the energetic neutral atom (ENA) producti on in the Mercury magnetosphere and the obtained ENA images for the equator ial and polar vantage points. The ENA fluxes are found to be 10(2)-10(3) (c m(2) sr s keV)(-1) and up to 10(4)-10(5) (cm(2) sr s keV)(-1) in the energy range 10-50 keV. Due to the small size of the magnetosphere, the particles injected in the tail can fill up the entire dayside magnetosphere making p ossible ENA imaging of the magnetospheric shape. The high variability of th e Hermean magnetosphere gives rise to pulsating ENA emissions (ENA "flashes ") which can be used to study the global dynamics. The ENA instrument requi rements, 10 degrees x 10 degrees angular resolution and 20 s accumulation t ime, can be easily met by modem ENA instrumentation. Therefore, ENA imaging of the Mercury magnetosphere is feasible. (C) 2001 Elsevier Science Ltd. A ll rights reserved.