High velocity clouds interacting with galactic halo plasma as a source of X-ray emission

B.J. Kellett, R. Bingham

Research output: Contribution to journalArticle


Several high velocity clouds (HVCs) are now known to be soft X-ray sources. In this paper we suggest that all interaction between the HVCs and the galactic halo is leading to plasma instabilities that generate energetic electrons which in turn generate X-ray emission. This process is essentially analogous to the interaction process between cornets and non-magnetized planets with the solar wind which is also known to lead to the generation of X-rays. We show that for reasonable assumptions about the galactic halo magnetic field, the X-ray emission can be converted into an estimate of the mean galactic halo density it the position of the cloud. This provides a method for estimating the baryonic mass of the plasma halo provided that we call obtain a good estimate for the distance to the HVC.
Original languageEnglish
Pages (from-to)111-118
Number of pages8
JournalJournal of Plasma Physics
Issue number2
Publication statusPublished - 1 Apr 2005


  • high velocity clouds
  • soft X-ray sources
  • energetic electrons
  • solar wind
  • galactic halo density
  • X-ray emission

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