uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
On the Origin of Perpendicular Ion Anisotropy Inside Dipolarizing Flux Bundles
Peking Univ, Sch Earth & Space Sci, Beijing, Peoples R China.
Peking Univ, Sch Earth & Space Sci, Beijing, Peoples R China.
Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA.
Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA.ORCID iD: 0000-0002-7489-9384
Show others and affiliations
2019 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 124, no 6, p. 4009-4021Article in journal (Refereed) Published
Abstract [en]

Perpendicular anisotropy of suprathermal ions, observed inside some of the dipolarizing flux bundles (DFBs) in the magnetotail plasma sheet, have been attributed to successive, betatron-type accelerations during the DFB entry of ambient ions. It has been unclear, however, where and how these ions enter the DFBs. The proposed locations include the DFB flanks where cross-tail drifting ions are picked up, and the DFB leading edge with sharp magnetic field gradient (the dipolarization front, DF). Here we examine the latter scenario, based on a simplistic, test particle approach, to predict the preferred conditions for the appearance of the DFB ion anisotropy. Our model predicts that the ion anisotropy would be stronger at locations closer to the neutral sheet and would appear preferentially in the DFB dawnside and central sectors rather than the duskside sector. We also predict that the ion anisotropy would more likely be observed in DFBs with higher propagation speeds. These properties can be understood in our model by the dawnward drift of ions during their DF penetration (attributed to the large magnetic gradient). To examine these predictions, we carry out a statistical survey based on observations from the THEMIS (Time History of Events and Macroscale Interactions during Substorms) mission, to show a clear dependence of the ion anisotropy on spacecraft location and the DFB propagation speed. These findings, therefore, are consistent with the scenario that the perpendicular ion anisotropy originates from the ion acceleration and penetration across sharp DFs.

Place, publisher, year, edition, pages
2019. Vol. 124, no 6, p. 4009-4021
National Category
Geophysics Fusion, Plasma and Space Physics
Identifiers
URN: urn:nbn:se:uu:diva-392050DOI: 10.1029/2019JA026519ISI: 000477723100011OAI: oai:DiVA.org:uu-392050DiVA, id: diva2:1349960
Available from: 2019-09-10 Created: 2019-09-10 Last updated: 2019-09-10Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full text

Search in DiVA

By author/editor
Liu, JiangPan, Dong-Xiao
By organisation
Swedish Institute of Space Physics, Uppsala Division
In the same journal
Journal of Geophysical Research - Space Physics
GeophysicsFusion, Plasma and Space Physics

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 3 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf