Cavitons and spontaneous hot flow anomalies in a hybrid-Vlasov global magnetospheric simulation

Research output: Contribution to journalArticle


  • Xochitl Blanco-Cano
  • Markus Battarbee
  • Lucile Turc
  • Andrew P. Dimmock
  • Emilia K.J. Kilpua
  • Sanni Hoilijoki
  • Urs Ganse
  • David G. Sibeck
  • Paul A. Cassak
  • Robert C. Fear
  • Riku Järvinen

  • Liisa Juusola
  • Yann Pfau-Kempf
  • Rami Vainio
  • Minna Palmroth

Research units

  • Universidad Nacional Autonoma de Mexico
  • University of Helsinki
  • Uppsala University
  • University of Colorado Boulder
  • NASA Goddard Space Flight Center
  • West Virginia University
  • University of Southampton
  • Finnish Meteorological Institute
  • University of Turku


In this paper we present the first identification of foreshock cavitons and the formation of spontaneous hot flow anomalies (SHFAs) with the Vlasiator global magnetospheric hybrid-Vlasov simulation code. In agreement with previous studies we show that cavitons evolve into SHFAs. In the presented run, this occurs very near the bow shock. We report on SHFAs surviving the shock crossing into the downstream region and show that the interaction of SHFAs with the bow shock can lead to the formation of a magnetosheath cavity, previously identified in observations and simulations. We report on the first identification of long-term local weakening and erosion of the bow shock, associated with a region of increased foreshock SHFA and caviton formation, and repeated shock crossings by them. We show that SHFAs are linked to an increase in suprathermal particle pitch-angle spreads. The realistic length scales in our simulation allow us to present a statistical study of global caviton and SHFA size distributions, and their comparable size distributions support the theory that SHFAs are formed from cavitons. Virtual spacecraft observations are shown to be in good agreement with observational studies.


Original languageEnglish
Pages (from-to)1081-1097
Number of pages17
JournalAnnales Geophysicae
Issue number4
Publication statusPublished - 8 Aug 2018
MoE publication typeA1 Journal article-refereed

Download statistics

No data available

ID: 27327302