Ion-Scale Wave Properties and Enhanced Ion Heating across the Low-Latitude boundary Layer during Kelvin-Helmholtz Instability

Thomas Moore, Katariina Nykyri, Andrew Dimmock

Research output: Contribution to journalArticleScientificpeer-review

12 Citations (Scopus)
128 Downloads (Pure)

Abstract

In the Earth's magnetosphere, the magnetotail plasma sheet ions are much hotter than in the shocked solar wind. On the dawn-sector, the cold-component ions are more abundant and hotter by 30-40 percent when compared to the dusk sector. Recent statistical studies of the flank magnetopause and magnetosheath have shown that the level of temperature asymmetry of the magnetosheath is unable to account for this, so additional physical mechanisms must be at play, either at the magnetopause or plasma sheet that contribute to this asymmetry. In this study, we perform a statistical analysis on the ion-scale wave properties in the three main plasma regimes common to flank magnetopause boundary crossings when the boundary is unstable to KHI: hot and tenuous magnetospheric, cold and dense magnetosheath and mixed [Hasegawa et al., 2004]. These statistics of ion-scale wave properties are compared to observations of fast magnetosonic wave modes that have recently been linked to Kelvin-Helmholtz (KH) vortex centered ion heating [Moore et al., 2016]. The statistical analysis shows that during KH events there is enhanced non-adiabatic heating calculated during ion scale wave intervals when compared to non-KH events. This suggests that during KH events there is more free energy for ion-scale wave generation, which in turn can heat ions more effectively when compared to cases when KH waves are absent. This may contribute to the dawn favored temperature asymmetry of the plasma sheet, recent studies suggest KH waves favor the dawn flank during Parker-Spiral (PS) interplanetary magnetic field (IMF).
Original languageEnglish
Pages (from-to)128-153
Number of pages26
JournalJournal of geophysical research: Space physics
Volume122
Issue number11
DOIs
Publication statusPublished - 18 Dec 2017
MoE publication typeA1 Journal article-refereed

Keywords

  • ion heating
  • Kelvin-Helmholtz instability
  • multi-scale

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