Overview of the Remote Sensing Observations from PSP Solar Encounter 10 with Perihelion at 13.3 R _⊙

Abstract

The closest perihelion pass of Parker Solar Probe (PSP), so far, occurred between 2021 November 16 and 26 and reached ∼13.29 R ☉ from Sun center. This pass resulted in very unique observations of the solar corona by the Wide-field Instrument for Solar PRobe (WISPR). WISPR observed at least 10 coronal mass ejections (CMEs), some of which were so close that the structures appear distorted. All of the CMEs appeared to have a magnetic flux rope (MFR) structure, and most were oriented such that the view was along the axis orientation, revealing very complex interiors. Two CMEs had a small MFR develop in the interior, with a bright circular boundary surrounding a very dark interior. Trailing the larger CMEs were substantial outflows of small blobs and flux-rope-like structures within striated ribbons, lasting for many hours. When the heliospheric plasma sheet was inclined, as it was during the days around perihelion on 2021 November 21, the outflow was over a very wide latitude range. One CME was overtaken by a faster one, with a resultant compression of the rear of the leading CME and an unusual expansion in the trailing CME. The small Thomson surface creates brightness variations of structures as they pass through the field of view. In addition to this dynamic activity, a brightness band from excess dust along the orbit of asteroid/comet 3200 Phaethon is also seen for several days.

Structure of the Plasma near the Heliospheric Current Sheet as Seen by WISPR/Parker Solar Probe from inside the Streamer Belt

“…Two such algorithms, which can reveal discrete features in both the K-corona (e.g., coronal transients and streamers) and F-corona (dust rings, asteroid and cometary trails), were described in the Appendix of Howard et al (2022). Here, we describe a third algorithm, which is used routinely to generate the L3 WISPR data products, which were used for most of the analysis in this work.…”

“…The idea behind this algorithm is similar to that used for the "LT" data product, described in Appendix B of Howard et al (2022). The procedure is totally heuristic and can be tuned by varying the free parameters of the algorithm-the results depend upon the spatial scales of the discrete features of interest.…”

“…As the mission progresses, PSP perihelion is lowered by gravity assists from encounters with Venus (Fox et al 2016). With decreasing distance to the Sun, WISPR's ability to resolve coronal features improves dramatically (Vourlidas et al 2016;Howard et al 2022). This is in part because the spacecraft is closer to the Sun and, more importantly, because WISPR's coronal images result from Thomson scattering of sunlight by coronal electrons.…”

“…The image on the left is the L3 processing with calibrated brightness (see Appendix). The right image is processed using an image-differencing process, which enhances the changes from image to image, named LW processing (see Appendix toHoward et al 2022). Using this processing, the very small variations in density along the rays are revealed.…”

Coronal Mass Ejection Deformation at 0.1 au Observed by WISPR

“…running window and kernel size affects the degree of detail in the resulting product, akin to a high-pass filter. For details the reader is referred to Howard et al (2022). A sigma filter as implemented in IDL (sigma_filter.pro) was applied to the background-corrected frames displayed in Figures 2, 3, and 10 to reduce the effect of point-like sources such as the star field.…”