The Solar Probe Cup on Parker Solar Probe

TL;DR

The Solar Probe Cup on NASA's Parker Solar Probe is a Faraday Cup instrument that measures solar wind plasma close to the Sun, providing valuable data on plasma heating and acceleration.

Contribution

This paper introduces the design and initial performance of the Solar Probe Cup instrument on PSP, enabling plasma measurements closer to the Sun than ever before.

Findings

Instrument functions well during initial orbit

Capable of measuring a wide range of proton and electron energies

Successfully collects data in extreme solar proximity

Abstract

The Solar Probe Cup (SPC) is a Faraday Cup instrument onboard NASA's Parker Solar Probe (PSP) spacecraft designed to make rapid measurements of thermal coronal and solar wind plasma. The spacecraft is in a heliocentric orbit that takes it closer to the Sun than any previous spacecraft, allowing measurements to be made where the coronal and solar wind plasma is being heated and accelerated. The SPC instrument was designed to be pointed directly at the Sun at all times, allowing the solar wind (which is flowing primarily radially away from the Sun) to be measured throughout the orbit. The instrument is capable of measuring solar wind ions with an energy/charge between 100 V and 6000 V (protons with speeds from $139-1072~km~s^{-1})$. It also measures electrons with an energy between 100 V and 1500 V. SPC has been designed to have a wide dynamic range that is capable of measuring protons and alpha particles at the closest perihelion (9.86 solar radii from the center of the Sun) and out to 0.25 AU. Initial observations from the first orbit of PSP indicate that the instrument is functioning well.