Radial Evolution of Non-Maxwellian Electron Populations Derived from Quasi-thermal Noise Spectroscopy: Parker Solar Probe Observations
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Authors
Zheng, X.
Liu, K.
Martinović, M.M.
Pierrard, V.
Klein, K.G.
Liu, M.
Abraham, J.B.
Liu, Y.
Luo, J.
Lin, X.
Liu, G.
Li, J.
Discipline
Physical sciences
Audience
Scientific
Date
2024Metadata
Show full item recordDescription
Understanding the transport of energy within space plasmas, particularly in the solar wind, remains a complex challenge. Accurate measurement of electron temperatures and their nonthermal characteristics is crucial for comprehending energy transport properties in plasmas. Quasi-thermal-noise (QTN) spectroscopy has emerged as a dependable tool for precise electron parameters assessment as it is less susceptible to spacecraft effects than particle detectors. In this study, we apply a QTN spectroscopy fitting method to analyze data from the Parker Solar Probe FIELDS radio instrument obtained during Encounters 2 through 13, under unbiased antenna conditions. We use the kappa function to characterize the electron velocity distribution and employ a fitting technique to derive the changes in each parameter across heliocentric distances ranging from 12 Rs to 76 Rs. Specifically, we find that the electron density scales as ne ∝ r−2.09±0.04 and the Te ∝ r−0.65±0.02. The distribution of the kappa index has three distinct regions as a function of radial distance from the Sun. Furthermore, we conduct a statistical analysis of solar wind energy flux which we finds follows a power-law relationship wtotal ∝ r−1.92±0.04.
Citation
Zheng, X.; Liu, K.; Martinović, M.M.; Pierrard, V.; Klein, K.G.; Liu, M.; Abraham, J.B.; Liu, Y.; Luo, J.; Lin, X.; Liu, G.; Li, J. (2024). Radial Evolution of Non-Maxwellian Electron Populations Derived from Quasi-thermal Noise Spectroscopy: Parker Solar Probe Observations. , The Astrophysical Journal, Vol. 977, Issue 1, A39, DOI: 10.3847/1538-4357/ad7d05.Identifiers
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Type
Article
Peer-Review
Yes
Language
eng