MMS Insights into CME Driven Sub-Alfvénic Solar Wind at 1 AU

Fuente: arXiv
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Autori principali: Gurram, Harsha, Chen, Li-Jen, Argall, Matthew R., Adhikari, Subash, Wilson, Lynn B., Shuster, Jason R., Wilder, Victoria D.
Natura: Preprint
Pubblicazione: 2026
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author Gurram, Harsha
Chen, Li-Jen
Argall, Matthew R.
Adhikari, Subash
Wilson, Lynn B.
Shuster, Jason R.
Wilder, Victoria D.
author_facet Gurram, Harsha
Chen, Li-Jen
Argall, Matthew R.
Adhikari, Subash
Wilson, Lynn B.
Shuster, Jason R.
Wilder, Victoria D.
contents We report the properties of electron distributions and turbulence during a Coronal Mass Ejection (CME) in April 2023 observed by Magnetospheric Multiscale (MMS). The CME exhibits a clear sheath and magnetic cloud (MC), and within the MC, the solar wind becomes sub-Alfvénic for two hours. We investigate plasma and turbulence properties of the sub-Alfvénic CME wind and compare them with those in the super-Alfvénic solar wind in the MC and CME sheath. Electrons within the sub-Alfvénic MC show significantly higher temperatures than those in the CME sheath and the super-Alfvénic MC, with their one-dimensional distributions revealing super-thermal tail and a depletion in electron populations between 15-50 eV. Within the CME sheath, isolated regions of electron heating are observed, where parallel energy flux is enhanced up to ~1 keV. Magnetic field fluctuations within the sub-Alfvénic MC interval exhibit negligible cross helicity and steeper-than-Kolmogorov scaling in the inertial range, with no clear spectral break. These fluctuations also show reduced intermittency at ion and sub-ion scales, emerging intermittency at electron scales, and weak magnetic compressibility. Together, these observations point to the presence of weak magnetohydrodynamic (MHD) turbulence within the sub-Alfvénic MC, resembling conditions commonly observed in planetary magnetospheres such as Jupiter's.
format Preprint
id arxiv_https___arxiv_org_abs_2604_12000
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle MMS Insights into CME Driven Sub-Alfvénic Solar Wind at 1 AU
Gurram, Harsha
Chen, Li-Jen
Argall, Matthew R.
Adhikari, Subash
Wilson, Lynn B.
Shuster, Jason R.
Wilder, Victoria D.
Space Physics
Solar and Stellar Astrophysics
Plasma Physics
We report the properties of electron distributions and turbulence during a Coronal Mass Ejection (CME) in April 2023 observed by Magnetospheric Multiscale (MMS). The CME exhibits a clear sheath and magnetic cloud (MC), and within the MC, the solar wind becomes sub-Alfvénic for two hours. We investigate plasma and turbulence properties of the sub-Alfvénic CME wind and compare them with those in the super-Alfvénic solar wind in the MC and CME sheath. Electrons within the sub-Alfvénic MC show significantly higher temperatures than those in the CME sheath and the super-Alfvénic MC, with their one-dimensional distributions revealing super-thermal tail and a depletion in electron populations between 15-50 eV. Within the CME sheath, isolated regions of electron heating are observed, where parallel energy flux is enhanced up to ~1 keV. Magnetic field fluctuations within the sub-Alfvénic MC interval exhibit negligible cross helicity and steeper-than-Kolmogorov scaling in the inertial range, with no clear spectral break. These fluctuations also show reduced intermittency at ion and sub-ion scales, emerging intermittency at electron scales, and weak magnetic compressibility. Together, these observations point to the presence of weak magnetohydrodynamic (MHD) turbulence within the sub-Alfvénic MC, resembling conditions commonly observed in planetary magnetospheres such as Jupiter's.
title MMS Insights into CME Driven Sub-Alfvénic Solar Wind at 1 AU
topic Space Physics
Solar and Stellar Astrophysics
Plasma Physics
url https://arxiv.org/abs/2604.12000