Oxygen-hydrogen differentiated observations from TWINS: The 22 July 2009 storm

P. W. Valek, J. Goldstein, D. J. McComas, R. Iiie, N. Buzulukova, M. C. Fok, J. D. Perez

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

The 22 July 2009 magnetic storm is the first significant storm during the emergence of the recent prolonged solar cycle minimum. This moderate storm (minimum Dst approximately ≤ -78 nT) has received a good deal of attention in the community. We present here global observations of the H and O populations in the inner magnetosphere using Energetic Neutral Atom (ENA) observations from the TWINS mission. We develop and provide the methodology for separating H and O ENAs, based on mass dependent differences in the pulse height distributions of the microchannel plate (MCP) based detectors. We present the first composition separated H and O ENA images at central energies of 16 and 32 keV. We also show that TWINS has sufficient angular resolution to separate the High Altitude Emissions (HAEs) from the Low Altitude Emissions (LAEs). We observe that all ENA emissions in this energy range quickly rise, but the O ENAs have a larger relative increase, and stay at elevated levels much longer, well into the recovery phase. Key Points We present the first 16 and 32 keV global O and H ENA images Sufficient spatial resolution to differentiate between H and O HAEs and LAEs We identified key differences in the evolution of H and O during this storm

Original languageEnglish (US)
Pages (from-to)3377-3393
Number of pages17
JournalJournal of Geophysical Research: Space Physics
Volume118
Issue number6
DOIs
StatePublished - Jan 1 2013
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Keywords

  • ENAs
  • magnetic storms
  • Oxygen
  • TWINS

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