In-Flight DC and Low-Frequency Electric Field Calibration for the Parker Solar Probe

Measurement of the quasi-DC and low-frequency vector electric fields in the solar wind is a prime objective of the NASA Parker Solar Probe (PSP) FIELDS Suite. The relatively short dipole sensors mounted close to the PSP spacecraft in highly variable plasma and spacecraft wake conditions make for a challenging measurement environment. However, the adaptation of standard in-flight E-field calibration procedures from decades of magnetospheric, ionospheric, and solar wind observations at 1 AU have proven quite successful during the first 3 perihelion encounters on PSP.

We shall present a summary of the operational scheme for the PSP E-field sensors, focusing particularly on the bias control and characterization schemes, and touching on the compromises required when sharing one set of antennas between receivers spanning DC to tens of MHz. We shall also describe the parameter estimation, calibration, and quality control algorithms developed for quasi-DC and low-frequency vector E-fields on PSP, and provide examples of optimal and less-than-optimal measurements on orbit.