The Parker Solar Probe WISPR Instrument: Results from the First Two Years of Observations

Abstract:

The Wide-field Imager for Solar Probe (WISPR) has now completed two years of its mission to image the solar atmosphere and heliosphere from a near-Sun vantage point. WISPR is the imaging instrument on board NASA’s Parker Solar Probe (PSP), launched in August 2018 with the mission of making measurements of the near-Sun plasma with gradually reduced perihelia from 35 Rs in 2018-19 to 9.8 Rs in 2025. Here we report the results from the imaging observations of the electron and dust corona taken by WISPR during these first two years of the mission. The WISPR instrument consists of two telescopes which together observe in the spacecraft ram direction along the ecliptic plane from 13.5 to 108 degrees from the Sun. To date PSP has successfully completed five perihelia, with the fifth perihelion descending to 26.8 Rs, and it is now on its way to a sixth perihelion, going down to 20 Rs, in September of 2020.

WISPR imaging has revealed the structure of magnetic features in the inner heliosphere, such as streamer substructure, streamer blowouts, coronal mass ejections, coronal rays, and reconnection events, from a vantage point significantly closer to their origin in the solar corona than has been possible before. This allows for examination of sub-structures of these features which are unresolved from prior remote sensing observations taken from 1AU. WISPR observations have presented us with evidence that the primordial dust orbiting the Sun is depleted near the Sun – a long-hypothesized phenomenon. In addition, WISPR has detected the circumsolar dust ring near Venus’ orbit and the dust trails left behind in the orbits of active asteroid 3200 Phaethon and comet 2P/Encke, as well as images of comets themselves as they near the perihelia of their orbits about the Sun. We will review these observations and analyses, and discuss prospects for what WISPR may be able to find for us as it continues its voyage down to 9.8 Rs.

We acknowledge the work of the PSP operations team. Parker Solar Probe was designed, built, and is now operated by the Johns Hopkins Applied Physics Laboratory as part of NASA’s Living with a Star (LWS) program (contract NNN06AA01C). We also acknowledge the work of the WISPR team developing and operating the instrument. WISPR is funded by NASA grant NNG11EK11I.