Parker Solar Probe Instruments: FIELDS

Tuesday, August 14, 2018

Parker Solar Probe works under extreme conditions as it gathers data in the Sun’s corona, grazing closer to our star than any spacecraft before. Its four instrument suites characterize the dynamic region close to the Sun by measuring particles and electric and magnetic fields, and each was specially designed to withstand the harsh radiation and temperatures they will encounter.


Surveyor of the invisible forces, the FIELDS instrument suite captures the scale and shape of electric and magnetic fields in the Sun’s atmosphere. FIELDS measures waves and turbulence in the inner heliosphere with high time resolution to understand the fields associated with waves, shocks and magnetic reconnection, a process by which magnetic field lines explosively realign.

FIELDS measures the electric field around the spacecraft with five antennas, four of which stick out beyond the spacecraft’s heat shield and into the sunlight, where they experience temperatures of 2,500 F. The 2-meter-long antennas are made of a niobium alloy, which can withstand extreme temperatures. FIELDS measures electric fields across a broad frequency range both directly, or in situ, and remotely. Operating in two modes, the four sunlit antennas measure the properties of the fast and slow solar wind — the flow of solar particles constantly streaming out from the Sun. The fifth antenna, which sticks out perpendicular to the others in the shade of the heat shield, helps make a three-dimensional picture of the electric field at higher frequencies.

A trio of magnetometers, each about the size of a fist, help FIELDS assess the magnetic field. A search coil magnetometer, or SCM, measures how the magnetic field changes over time. Since changing magnetic fields induce a voltage in the coil, it’s possible to track how the magnetic field changes by measuring that voltage. Two identical fluxgate magnetometers, MAGi and MAGo, measure the large-scale coronal magnetic field. The fluxgate magnetometers are specialized for measuring the magnetic field further from the Sun where it varies at a slower rate, while the search coil magnetometer is necessary closer to the Sun where the field changes quickly, as it can sample the magnetic field at a rate of two million times per second.

FIELDS was designed, built, and is operated by a team lead by the Space Sciences Laboratory at the University of California, Berkeley with principal investigator Stuart D. Bale.