イオンスラスタ排出ビームイオンのENA観測への応用に関する研究

抄録

The observing method that uses ENA (Energetic Neutral Atom), produced by Charge Exchange Collision, is studied and researched by ISAS in order to estimate the density of neutral particles in the upper atmosphere. Its method is called ENA observation. At present, the ENA observation is done by Charge Exchange Collision between neutrals in the upper atmosphere and the ions in the magnetospheric ring current field that is activated by solar wind. But in this method, it is difficult to separate the informations between neutrals and ions from ENA data because the ions in the magnetospheric ring current field are the natural origin and their energies are not constant. In this study, we propose the new method of ENA observation that uses ions exhausted from ion thruster. Ions from ion thruster are the artificial ones and are more suitable for ENA observation because their energies and densities can be controlled. We evaluate the possibility of application of ion thruster’s exhausted ions to ENA observation. Analytical results show the range of altitude and the operating conditions of ion thruster that this method effectively can apply.