The collision meter: An experimental technique to measure charged-neutral interactions and gas composition in the upper atmosphere

A method of exploring the upper atmosphere through measurements of charged-neutral particle collisions is described. The method utilizes a charged particle beam which is injected into space from an in-situ probe and returns to the probe under its gyromotion about the ambient magnetic field. Measurements of the attenuation of the returned beam provide direct information on the collisional cross sections between the beam particles and the ambient medium. The method is discussed and expected measurements displayed and evaluated. In addition to providing new information on collision processes in the upper atmosphere, it is shown that this method has the potential for returning very accurate determinations of the densities of the major neutral gas species, including atomic oxygen. Initial in-situ experiments and directions for extension and further use are discussed.