Simulated Encounters of Parker Solar Probe with A Coronal-Hole Jet

TL;DR

This study simulates Parker Solar Probe encounters with coronal-hole jets using 3D MHD models, identifying distinct in situ signatures of different jet regions and predicting numerous encounters during the mission.

Contribution

It introduces a detailed 3D MHD simulation of CH jets tailored for PSP encounters, revealing specific signatures of jet regions and their detectability in situ.

Findings

Distinct wave modes and signatures identified in jet regions

Leading Alfvén wave front characterized by trans-Alfvénic flows and shock signatures

Remote wake region shows mixed characteristics of other jet regions

Abstract

Solar coronal jets are small, transient, collimated ejections most easily observed in coronal holes (CHs). The upcoming Parker Solar Probe (PSP) mission provides the first opportunity to encounter CH jets in situ near the Sun and examine their internal structure and dynamics. Using projected mission orbital parameters, we have simulated PSP encounters with a fully three-dimensional magnetohydrodynamic (MHD) model of a CH jet. We find that three internal jet regions, featuring different wave modes and levels of compressibility, have distinct identifying signatures detectable by PSP. The leading Alfv\'{e}n wave front and its immediate wake are characterized by trans-Alfv\'{e}nic plasma flows with mild density enhancements. This front exhibits characteristics of a fast switch-on MHD shock, whose arrival is signaled by the sudden onset of large-amplitude transverse velocity and magnetic-field oscillations highly correlated in space and time. The trailing portion is characterized by supersonic but sub-Alfv\'{e}nic outflows of dense plasma with uncorrelated velocity and magnetic-field oscillations. This compressible region contains most of the jet's mass. The volume between the immediate wake and dense jet, the remote wake, mixes and transitions the characteristics of the two other regions. In addition to probing each region separately, we also simulate a co-rotational PSP-jet encounter. In this scenario, the simulated spacecraft hovers over the jet-producing CH, as may occur during the mission's co-rotational phases, sampling each jet region in turn. We estimate that PSP will encounter numerous CH jets over the lifetime of the mission.