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Ann. Geophys., 22, 2073-2080, 2004
www.ann-geophys.net/22/2073/2004/
© European Geosciences Union 2004
Spacecraft potential effects on electron moments derived from a perfect plasma detector
V. Génot1,* and S. J. Schwartz1
1Astronomy Unit, Queen Mary, University of London, Mile End Road, London E1 4NS, England, UK
*Now permanently at CESR, Toulouse, France
Abstract. A complete computation of the effect of the spacecraft potential
on electron moments is presented. We adopt the perfect detector
concept to estimate how measured density, velocity and temperature
are affected by the constraints imposed by the detector, such as
the finite lower energy cutoff and the spacecraft potential. We
investigate the role of the potential in different plasma regimes
usually crossed by satellites. It appears that the solar wind is
the region where the moments are most compromised, as the particle
temperature is low. To a lesser extent the moments calculated in
the magnetosheath may also deviate from the real moments,
displaying up to 40% overestimation for the density under typical
detector operation. The analysis allows us to identify a range of
spacecraft potential values which minimizes the variation in the
estimation; it is found that it corresponds to the common value
adopted by potential controlling experiments.
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