Investigating Coronal Holes and CMEs as Sources of Brightness Depletion Detected in PSP/WISPR Images

The Parker Solar Probe (PSP) mission provides a unique opportunity to observe the solar corona from distances below 20 R _☉ . In this work, we utilize white light images from the Wide-field Imager for Solar PRobe aboard the PSP from solar encounters 10 through 13 to examine the causes of brightness depletions of the corona during the rapid transit of PSP through the perihelia of its orbit. We analyze the effect of (1) coronal holes (CHs) and (2) energetic coronal mass ejection (CME) events on the observed brightness of the images. We speculate on the causes of the brightness depletions, ascribing them to the evacuation of (1) free electrons (reduced K-corona) and (2) interplanetary dust (reduced F-corona). In particular, we show that (1) the presence of CHs in all of the orbits is directly correlated with the depletion of the global white light emission recorded, and (2) a huge CME event in encounter 13 caused a very deep depletion in its wake that removed the electron content as well as some of the interplanetary dust.