The heliospheric current sheet and plasma sheet during Parker Solar Probe’s first orbit

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Title: The heliospheric current sheet and plasma sheet during Parker Solar Probe’s first orbit
Authors: Lavraud, B
Fargette, N
Réville, V
Szabo, A
Huang, J
Rouillard, AP
Viall, N
Phan, TD
Kasper, JC
Bale, SD
Berthomier, M
Bonnell, JW
Case, AW
Dudok de Wit, T
Eastwood, JP
Génot, V
Goetz, K
Griton, LS
Halekas, JS
Harvey, P
Kieokaew, R
Klein, KG
Korreck, KE
Kouloumvakos, A
Larson, DE
Lavarra, M
Livi, R
Louarn, P
MacDowall, RJ
Maksimovic, M
Malaspina, D
Nieves-Chinchilla, T
Pinto, RF
Poirier, N
Pulupa, M
Raouafi, NE
Stevens, ML
Toledo-Redondo, S
Whittlesey, PL
Item Type: Journal Article
Abstract: We present heliospheric current sheet (HCS) and plasma sheet (HPS) observations during Parker Solar Probe's (PSP) first orbit around the Sun. We focus on the eight intervals that display a true sector boundary (TSB; based on suprathermal electron pitch angle distributions) with one or several associated current sheets. The analysis shows that (1) the main density enhancements in the vicinity of the TSB and HCS are typically associated with electron strahl dropouts, implying magnetic disconnection from the Sun, (2) the density enhancements are just about twice that in the surrounding regions, suggesting mixing of plasmas from each side of the HCS, (3) the velocity changes at the main boundaries are either correlated or anticorrelated with magnetic field changes, consistent with magnetic reconnection, (4) there often exists a layer of disconnected magnetic field just outside the high-density regions, in agreement with a reconnected topology, (5) while a few cases consist of short-lived density and velocity changes, compatible with short-duration reconnection exhausts, most events are much longer and show the presence of flux ropes interleaved with higher-β regions. These findings are consistent with the transient release of density blobs and flux ropes through sequential magnetic reconnection at the tip of the helmet streamer. The data also demonstrate that, at least during PSP's first orbit, the only structure that may be defined as the HPS is the density structure that results from magnetic reconnection, and its byproducts, likely released near the tip of the helmet streamer.
Date of Acceptance: 26-Apr-2020
DOI: 10.3847/2041-8213/ab8d2d
ISSN: 2041-8205
Publisher: American Astronomical Society
Start Page: 1
End Page: 8
Journal / Book Title: Letters of the Astrophysical Journal
Volume: 894
Issue: 2
Copyright Statement: © 2020. The American Astronomical Society. All rights reserved. This is an author-created, un-copyedited version of an article accepted for publication in Astrophysical Journal Letters. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher authenticated version is available online at
Sponsor/Funder: Science and Technology Facilities Council (STFC)
Funder's Grant Number: ST/S000364/1
Keywords: Science & Technology
Physical Sciences
Astronomy & Astrophysics
Slow solar wind
Solar coronal streamers
Solar coronal transients
Solar magnetic reconnection
Space plasmas
Plasma jets
0201 Astronomical and Space Sciences
Astronomy & Astrophysics
Publication Status: Published online
Online Publication Date: 2020-05-08
Appears in Collections:Space and Atmospheric Physics

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