A NEW TECHNIQUE FOR IN-SITU MEASUREMENT OF THE COMPOSITION OF NEUTRAL GAS IN INTERPLANETARY SPACE

Neutral atoms filling interplanetary space play an important role in many processes relevant to the formation and evolution of the Solar System. A novel experimental approach for in situ atom detection is proposed. The technique is based on the conversion of neutral atoms to negative ions at a specially prepared sensitive surface. Negative ions are subsequently analyzed and detected in an essentially noise-free mode. As an application of the technique, in situ study of the composition of neutral interstellar atoms that penetrate the Solar System from the local interstellar medium is considered. It is shown that interstellar H, D and O atoms as well as, possibly, H-2 molecules can be measured by the proposed technique. The experiment can be performed from a high-apogee Earth-orbiting satellite or from a deep space probe. Other possible applications of the technique are discussed briefly.