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2012ja017673.pdf | 1.36 MB | Adobe PDF | 見る/開く |
タイトル: | Plasma particle simulations on stray photoelectron current flows around a spacecraft |
著者: | Miyake, Y. Usui, H. Kojima, H. Nakashima, H. |
キーワード: | double-probe technique instruments and techniques particle simulation photoelectron current spacecraft charging |
発行日: | Sep-2012 |
出版者: | American Geophysical Union |
誌名: | Journal of Geophysical Research: Space Physics |
巻: | 117 |
号: | A9 |
論文番号: | A09210 |
抄録: | In tenuous space plasmas, photoelectron flows produce complex current paths among multiple conducting elements of spacecraft, which may influence the current–voltage characteristics of double-probe electric field sensors. We performed full-particle simulations on this effect by assuming a sensor configuration that is typical of recent designs like those on Cluster, THEMIS, and BepiColombo/MMO the spherical probe is separated from a conducting boom by biased electrodes known as the 'stub' and the 'guard'. The assumed bias potential scheme corresponds to that planned for BepiColombo/MMO and is different from those used in the other satellites. The analysis focuses on stray photoelectron currents flowing from these electrodes and a spacecraft body. Photoelectrons approaching the probe are commonly repelled by the guard, the potential of which is strongly biased negatively, and are subsequently affected by the probe potential. Consequently, the photoelectron current magnitude increases with increasing probe potential regardless of their origins, when the probe operates between the plasma and floating spacecraft potentials. The result indicates that both photoelectron currents from the spacecraft body and biased electrodes can be minimized by selecting the probe working potential as close as possible to the plasma potential. We also examine the photoelectron current dependence on the presence or absence of the guard electrode operation and confirm a positive effect of reducing the photoelectron current from the spacecraft. However, negative side effects of the guard operation enhance the photoelectron currents from the stub and guard, when the probe operates nearly at the plasma potential. |
著作権等: | ©2012. American Geophysical Union. |
URI: | http://hdl.handle.net/2433/193713 |
DOI(出版社版): | 10.1029/2012ja017673 |
出現コレクション: | 学術雑誌掲載論文等 |
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