Parker Solar Probe FIELDS instrument charging in the near Sun
environment: Part II - Comparison of In-Flight Data and Modeling Results
Abstract
This research shows Part II of the Spacecraft Interaction Plasma
Software (SPIS) used to model the Parker Solar Probe (PSP) FIELDS
instrument and its interactions with the Solar Wind. Flight data was
used to run the PSP model and compared with models using past predicted
parameters. The effect of voltage biasing between the antenna, its
shield, and the spacecraft on the current balance of each surface was
investigated at first perihelion (0.16AU). The model data was reduced to
I-V curves to find current saturations (analysis results 52µA versus
flight results 54-72 µA), and sheath resistances (analysis results of
307 kΩ versus flight results of 51 kΩ). The recommended bias current to
ensure optimal sensitivity of the FIELDS antenna was between -52 µA and
-22 µA, which corresponded to a differential potential with respect to
the spacecraft between -5V and 5V. The analysis also shows that plasma
sheath of the FIELDS antenna and the plasma sheath of the FIELDS shield
interacted between each other with an impedance of
~220kΩ.