Simulating White-Light Images of Coronal Structures for Parker Solar Probe/WISPR: Study of the Total Brightness Profiles

Abstract

The Wide-field Imager for Parker Solar Probe (WISPR) captures unprecedented white-light images of the solar corona and inner heliosphere. Thanks to the uniqueness of Parker Solar Probe's (PSP) orbit, WISPR is able to image ``locally'' coronal structures at high spatial and time resolutions. The observed plane of sky, however, rapidly changes because of the PSP's high orbital speed. Therefore, the interpretation of the dynamics of the coronal structures recorded by WISPR is not straightforward. A first study, undertaken by \citet{Liewer2019}, shows how different coronal features (e.g., streamers, flux ropes) appear in the field of view of WISPR by means of raytracing simulations. In particular, they analyze the effects of the spatial resolution changes on both the images and the associated height-time maps, and introduce the fundamentals for geometric triangulation. In this follow-up paper, we focus on the study of the total brightness of a simple, spherical, plasma density structure, to understand how the analysis of Thomson-scattered emission by the electrons in a coronal feature can shed light into the determination of its kinematic properties. We investigate two cases: {\it (a)} a density sphere at a constant distance from the Sun for different heliographic longitudes; {\it (b)} a density sphere moving outwardly with constant speed. The study allows us to characterize the effects of the varying heliocentric distance of the observer and scattering angle on the total brightness observed, which we exploit to contribute to a better determination of the position and speed of the coronal features observed by WISPR.

arXiv comment26 pages, 11 figures. Accepted for publication in Solar Physics

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Cited by in corpus (4)

• Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum
• Trajectory Determination for Coronal Ejecta Observed by WISPR/Parker Solar Probe
• Constraints on the variable nature of the slow solar wind with the Wide-Field Imager on board the Parker Solar Probe
• Tracking solar wind flows from rapidly varying viewpoints by the Wide-field Imager for Parker Solar Probe