A PSP Perihelion

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Revision as of 15:26, 21 January 2020

Introduction

The [Parker Solar Probe] is edging its way into the innermost heliosphere, one perihelion at a time. This Nugget deals with planning for these occasions, which may produce the major breakthrough of an actual identification of the magnetic connectivity between a 2D point on the surface of the Sun with a point in the 3D space that the spacecraft traverses. It might be an actual *event*, of the sort long sought for by RHESSI in the form of a match between SEP electrons and flare ejecta. But more likely it will have to do with the [*strahl*] component of the solar wind.

In either case we need to proceed from our existing understanding of the coronal magnetic field (limited) to make a best guess about where to look. This is vitally important for imaging instruments with small fields of view. The imminent perihelion is the first really good one, with the footpoint on the visible hemisphere, but there will be a continuous set of future perihelia with the same issue, as we proceed into Cycle 25.

Identifying the likely footpoint

An expert team has tackled this problem, with a helpful Web site at

 https://whpi.hao.ucar.edu/whpi_campaign-cr2226.php

in which one can see updating maps providing target information. The example map at the time of writing this Nugget is here as Figure 1.

Figure 1: The "concensus target" as predicted from contemporaneous databases, marked with yellow squares. The heliographic current sheet (red) shows the property expected for solar minimum: it hugs the equator.

North or South?

Conclusions

Bibliography