Ion energization during substorms at Mercury

D. C. Delcourt, F. Leblanc, K. Seki, N. Terada, T. E. Moore, M. C. Fok

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

We investigate the dynamics of magnetospheric ions during transient reconfigurations of Mercury's magnetotail. At Earth, numerous observations during similar events reveal a prominent energization (up to the hundreds of keV range) of heavy ions (O+) originating from the topside ionosphere. This energization likely results from a resonant nonadiabatic interaction with the electric field that is induced by dipolarization of the magnetic field lines, the time scale of this reconfiguration being comparable to the heavy ion cyclotron period. The question then arises whether such an energization may occur at Mercury. Using single-particle simulations in time-varying electric and magnetic fields, we show that prominent nonadiabatic heating is obtained for ions with small mass-to-charge ratios (e.g., H+, He+). As for heavy ions (e.g., Na+, Ca+) that have cyclotron periods well above the time scale of the magnetotail reconfiguration (several seconds), a weaker energization is obtained. The resonant heating mechanism that we examine here may be of importance for solar wind protons that gain access to the inner hermean magnetotail as well as for light ions of planetary origin that directly feed the near-Mercury plasma sheet.

Original languageEnglish
Pages (from-to)1502-1508
Number of pages7
JournalPlanetary and Space Science
Volume55
Issue number11
DOIs
Publication statusPublished - 2007 Sep
Externally publishedYes

Keywords

  • Charged particle motion and acceleration
  • Mercury's magnetosphere
  • Substorms

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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