Abstract
The sheath plasma of interplanetary coronal mass ejections (ICMEs) is highly compressed, heated, turbulent, and magnetically intense relative to the ambient solar wind. In this Letter, we perform a detailed study of proton temperature anisotropy within the 333 ICME sheath regions observed on board the Wind spacecraft spanning the years 1995–2015. Our observations show that marginal stability thresholds of mirror mode and firehose instabilities predominantly constrain the proton temperature anisotropy within these sheath regions regardless of ICME sheath plasma speed. This is true even when the plasma beta values are less than 2, a parameter space that should have favored the prevalence of parallel firehose and proton cyclotron instabilities according to linear stability analysis. This investigation demonstrates the critical role played by distinct plasma instabilities in shaping the evolution of ICME sheath plasma compared to the broader solar wind environment.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
