Simulation of the Cluster-Spacecraft Floating Probe Potential

In this paper, a numerical model of the Cluster-spacecraft electric potential has been developed and validated. This model provides a good fit to the plasma density as a function of spacecraft chassis potential relative to a Langmuir probe as recorded along the Cluster-spacecraft orbit when the plasma density was between 1 and 80 cm
^-3
during a plasmaspheric crossing. The model is used to assess the uncertainty in density-determination methods based on potential measurements. Furthermore, this model provides constraints on the parameters suitable for describing the photoelectron emission and might be used in the future to estimate plasma temperature in space