TitleAnticorrelation between the Bulk Speed and the Electron Temperature in the Pristine Solar Wind: First Results from the Parker Solar Probe and Comparison with Helios
Publication TypeJournal Article
Year of Publication2020
AuthorsMaksimovic, M, Bale, SD, Berčič, L, Bonnell, JW, Case, AW, T. de Wit, D, Goetz, K, Halekas, JS, Harvey, PR, Issautier, K, Kasper, JC, Korreck, KE, V. Jagarlamudi, K, Lahmiti, N, Larson, DE, Lecacheux, A, Livi, R, MacDowall, RJ, Malaspina, DM, Martinović, MM, Meyer-Vernet, N, Moncuquet, M, Pulupa, M, Salem, C, Stevens, ML, Štverák, Š, Velli, M, Whittlesey, PL
JournalThe Astrophysical Journal Supplement Series
Volume246
Issue2
Pagination62
Date Published02/2020
Keywordsparker solar probe; Solar Probe Plus
Abstract

We discuss the solar wind electron temperatures Te as measured in the nascent solar wind by Parker Solar Probe during its first perihelion pass. The measurements have been obtained by fitting the high-frequency part of quasi-thermal noise spectra recorded by the Radio Frequency Spectrometer. In addition we compare these measurements with those obtained by the electrostatic analyzer discussed in Halekas et al. These first electron observations show an anticorrelation between Te and the wind bulk speed V: this anticorrelation is most likely the remnant of the well-known mapping observed at 1 au and beyond between the fast wind and its coronal hole sources, where electrons are observed to be cooler than in the quiet corona. We also revisit Helios electron temperature measurements and show, for the first time, that an in situ ( T e ,V Te,V ) anticorrelation is well observed at 0.3 au but disappears as the wind expands, evolves, and mixes with different electron temperature gradients for different wind speeds.

URLhttps://iopscience.iop.org/article/10.3847/1538-4365/ab61fch
DOI10.3847/1538-4365/ab61fc
Short TitleApJS


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