|
|
 |
|
|
Ann. Geophys., 23, 2813-2823, 2005
www.ann-geophys.net/23/2813/2005/
© European Geosciences Union 2005
Spacecraft potential control for Double Star
K. Torkar1, H. Arends2, W. Baumjohann1, C. P. Escoubet2, A. Fazakerley3, M. Fehringer2, G. Fremuth1, H. Jeszenszky1, G. Laky1, B. T. Narheim4, W. Riedler1, F. Rüdenauer5, W. Steiger5, K. Svenes4, and H. Zhao6
1Space Research Institute, Austrian Academy of Sciences, A-8042 Graz, Austria
2ESA/ESTEC, NL-2200 AG Noordwijk, The Netherlands
3Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, UK
4Norwegian Defence Research Establishment (FFI), N-2007 Kjeller, Norway
5Austrian Research Centers Seibersdorf, A-2444 Seibersdorf, Austria
6Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080, P. R. China
Abstract. The spacecraft potential of Double Star TC-1 is positive in large parts
of the orbits due to the photo-effect from solar EUV irradiation. These
positive potentials typically disturb low energy plasma measurements on
board. The potential can be reduced, and thereby the particle measurements
improved, by emitting a positive ion beam. This method has successfully been
applied on several other spacecraft and it has also been chosen for TC-1.
The instrument TC-1/ASPOC is a derivative of the Cluster/ASPOC
instruments, from which it has inherited many features. The paper describes
the adaptations and further developments made for the ion emitters and the
electronics. The instrument performs very well and can support higher beam
currents than on Cluster. The expected significant improvement of the low
energy particle measurements on board was indeed observed. The modifications
of the electron distributions are analysed for a one-time interval when the
spacecraft was located in the magnetosheath. The change in the potential due
to the ion beam was determined, and first studies of the 3-D electron
distributions in response to the spacecraft potential control have been
performed, which indicate that the method works as expected.
Full Article in PDF (5957 KB) |
|
|
