Estimation of the Electron Density From Spacecraft Potential During High‐Frequency Electric Field Fluctuations

Abstract

AbstractSpacecraft potential has often been used to infer electron density with much higher time resolution than is typically possible with plasma instruments. However, recently, two studies by Torkar et al. (2017, https://doi.org/10.1002/2017JA024724) and Graham, Vaivads, Khotyaintsev, Eriksson, et al. (2018, https://doi.org/10.1029/2018JA025874) have shown that external electric fields can also have an effect on the spacecraft potential by enhancing photoelectron escape from the surface. Consequently, should the electron density derived from the spacecraft potential be used during an event with a large electric field, the estimation would be contaminated and the user would see the effects of the electric field rather than density perturbations. The goal of this paper is to propose a method to remove the electric field effects to allow the density derived from spacecraft potential to be used even during large‐amplitude wave events such as Langmuir waves or upper hybrid waves.