The Warped Heliospheric Current Sheet

Peng, Jinfang; Liu, Yong C.‐M.; Huang, Jia; Klecker, B.; Wang, Chi

doi:10.1029/2019ja026517

Cited by 3 publications

(2 citation statements)

References 51 publications

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“…The PCS crossings could be caused by the warped HCSs (e.g., Peng et al 2019), but their signatures of long duration and recurrent appearance imply that they are most likely generated by the traveling large plasma blobs bulging onto both sides of the HCS crossings (e.g., Phan et al 2004;Lavraud et al 2020;Phan et al 2021). As a result, the PCS crossings represent the pristine state of the solar wind from the streamer belt, and it is valuable to compare the PCS solar wind with the HCS solar wind (i.e., HPS) to infer their differences in kinetic properties and origins.…”

Section: Introductionmentioning

confidence: 99%

Parker Solar Probe Observations of High Plasma β Solar Wind from the Streamer Belt

Huang

Kasper

Larson

et al. 2023

ApJS

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In general, slow solar wind from the streamer belt forms a high plasma β equatorial plasma sheet around the heliospheric current sheet (HCS) crossing, namely, the heliospheric plasma sheet (HPS). Current Parker Solar Probe (PSP) observations show that the HCS crossings near the Sun could be full or partial current sheet (PCS) crossings, and they share some common features but also have different properties. In this work, using the PSP observations from encounters 4–10, we identify streamer belt solar wind from enhancements in plasma β, and we further use electron pitch angle distributions to separate it into HPS solar wind around the full HCS crossings and PCS solar wind in the vicinity of PCS crossings. Based on our analysis, we find that the PCS solar wind has different characteristics as compared with HPS solar wind: (a) the PCS solar wind could be non-pressure-balanced structures rather than magnetic holes, and the total pressure enhancement mainly results from the less reduced magnetic pressure; (b) some of the PCS solar wind is mirror-unstable; and (c) the PCS solar wind is dominated by very low helium abundance but varied alpha–proton differential speed. We suggest that the PCS solar wind could originate from coronal loops deep inside the streamer belt, and it is pristine solar wind that still actively interacts with ambient solar wind; thus, it is valuable for further investigations of the heating and acceleration of slow solar wind.

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Section: Introductionmentioning

confidence: 99%

Parker Solar Probe Observations of High Plasma β Solar Wind from the Streamer Belt

Huang

Kasper

Larson

et al. 2023

ApJS

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“…Only 14% of the HCS crossings show angles between normal vectors greater than 45 • . For these cases, a possible explanation is found in the models of the global structure of the solar wind; Peng et al (2019) conclude that in some cases, the HCS is better described with an Archimedean spiral, superposed by small-scale ripples. Israelevich et al (2001) carried out numerical simulations with the Alfvén conceptual model including the radial and azimuthal components of the electric current, concluding that current sheet warping exhibits a spiral structure and a high dependency with the solar cycle.…”

Section: Principal Component Analysismentioning

confidence: 84%

Analysis of the heliospheric current sheet’s local structure based on a magnetic model

Arrazola

Blanco

Hidalgo

2022

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Context. An approach to the problem of estimating several physical properties of the heliospheric current sheet (HCS) local structure from a single spacecraft observation point of view was published in 2003. This method, HYperbolic TAngent ROtation (HYTARO), is based on the following two main assumptions: (a) that the HCS is locally flat, and (b) that its magnetic topology is described by a modified Harris field. Aims. A revision of HYTARO by including the spacecraft’s trajectory and developing a more precise procedure able to reduce the number of the required fit parameters is presented in this paper. Methods. This magnetic topology is proposed for the HCS’s local field at 1 AU, and it was applied as a fit function to a collection of 40 HCS crossings detected by the WIND spacecraft during the solar minimum. The estimated HCS local parameters (i.e., orientation and width) are consistent with previous works, which used the minimum variance analysis or the coplanarity variance analysis, and this is inferred from HYTARO results. One of the points of discussion about HYTARO was determining if it was necessary to apply two or three rotations to characterize the field’s relative orientation with respect to the current sheet (CS) plane. As principal component analysis (PCA) is a method to decompose a set of data into no correlated components by identifying eigenvalues and eigenvectors, it is feasible to analyze the possibility of reducing the dimensionality of the problem. Results. HYTARO gives a qualitative description of the observed magnetic field during an HCS crossing. The number of free parameters from the original HYTARO method has been reduced including the relative spacecraft trajectory through the CS and adding a background field related to each Cartesian component. Further, PCA has been implemented to justify applying two rotations with the HYTARO model. The dimensionality is another way to explore the number of rotations needed to relate the field in the local system with the field in GSE coordinates.

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