@inproceedings{oai:jaxa.repo.nii.ac.jp:00006404,
 author = {Engwall, E. and Eriksson, A. I.},
 book = {宇宙航空研究開発機構特別資料, JAXA Special Publication: 9th Spacecraft Charging Technology Conference},
 month = {Aug},
 note = {Behind a spacecraft in a supersonic ion flow, a negatively charged wake will form. In a sufficiently tenuous plasma, where the potential of a sunlit spacecraft becomes positive, the size of the ion wake can become very much larger than what may be expected from the spacecraft geometrical size. This occurs if the energy of the flowing ions is less than what is needed to overcome the positive spacecraft potential. As the ion flow must be supersonic, this means that the plasma flow has to be quite cold. It turns out that such conditions are quite common in the terrestrial magnetosphere, particularly in the polar wind region. The polar wind cold plasma flow at geocentric distances outside 10 Earth radii can have ion flow kinetic energy around 10 eV, ion temperature of a few eV and be so tenuous that the potential of a spacecraft reaches above 20 V. This plasma is rarely measured on scientific spacecraft, as the ions cannot reach an ion detector mounted on the highly positive spacecraft. Consequently, there are only a few studies of its properties and distribution. However, the cold ion density can be estimated by comparing the number of ions actually detected on the spacecraft with independent density estimates, for example spacecraft potential measurements or wave signatures. Another effect of the negatively charged wake is its impact on electric field measurements on the spacecraft, which shows a clear signature of the wake electrostatic potential. While this is a contamination to the measurement of the natural electric field, it is also potentially useful to derive flow properties like velocity and temperature. In order to understand the problems and exploit the possibilities of this effect, we have analyzed data from the Cluster double probe instrument EFW and used the PicUp3D code to perform PIC simulations. This study has given new information on the properties of the wake, as well as the photoemission from the electric field probes., 資料番号: AA0049206089, レポート番号: JAXA-SP-05-001E},
 pages = {772--779},
 publisher = {宇宙航空研究開発機構, Japan Aerospace Exploration Agency (JAXA)},
 title = {Cold magnetospheric plasma flows and spacecraft wakes: PicUp3D simulations and Cluster data},
 volume = {JAXA-SP-05-001E},
 year = {2005}
}