The low-energy neutral atom imager for IMAGE

The 'Imager for Magnetosphere-to-Aurora Global Exploration' (IMAGE) will be launched early in the year 2000. It will be the first mission dedicated to imaging, with the capability to determine how the magnetosphere changes gl obally in response to solar storm effects in the solar wind, on time scales as short as a few minutes. The low energy neutral atom (LENA) imager uses a new atom-to-negative ion surface conversion technology to image the neutr al atom flux and measure its composition (H and O) and energy distribution (10 to 750 eV). LENA uses electrostatic optics techniques for energy (per c harge) discrimination and carbon foil time-of-flight techniques for mass di scrimination. It has a 90 degrees x8 degrees field-of-view in 12 pixels, ea ch nominally 8 degrees x8 degrees. Spacecraft spin provides a total field-o f-view of 90 degrees x360 degrees, comprised of 12x45 pixels. LENA is desig ned to image fast neutral atom fluxes in its energy range, emitted by auror al ionospheres or the sun, or penetrating from the interstellar medium. It will thereby determine how superthermal plasma heating is distributed in sp ace, how and why it varies on short time scales, and how this heating is dr iven by solar activity as reflected in solar wind conditions.