Dispersive Alfvén Wave Control of O+ Ion Outflow and Energy Densities in the Inner Magnetosphere

A. J. Hull, C. C. Chaston, J. W. Bonnell, J. R. Wygant, C. A. Kletzing, G. D. Reeves, A. Gerrard

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

The relationship between dispersive Alfvén waves (DAWs), magnetospheric activity, and O+ ion outflow/energy density is examined using measurements from the Van Allen Probes. We show that correlated DAW activity and O+ outflow/energization is a characteristic feature of the inner magnetosphere during active conditions and during storms persists for several hours over large L-shell and azimuthal ranges of the plasma sheet. Though enhanced during substorm and storm active periods, these correlated features are most intense during geomagnetic storms. Comparisons show a linear relationship between DAW electric (and magnetic) field energy density and outflowing O+ energy. Statistical measurements from a large number of storms also reveal a linear relationship between DAW energy density and gross enhancements in energetic O+ energy densities. These observations support the notion that DAWs play an important role in the energization of O+ ions into and within the inner magnetosphere.

Original languageEnglish (US)
Pages (from-to)8597-8606
Number of pages10
JournalGeophysical Research Letters
Volume46
Issue number15
DOIs
StatePublished - Aug 16 2019

Bibliographical note

Funding Information:
This research was supported by NASA grant NNX17AG69G and Van Allen Probes funding provided under NASA prime contract NAS5-01072, including the EFW investigation (PI: J.R. Wygant, University of Minnesota), the EMFISIS investigation (PI: C.A. Kletzing, University of Iowa) under JHU/APL contract 921647, RBSP-ECT JHU/APL under contract 967399, and RBSP-RBSPICE JHU/APL under contract 937836 to the New Jersey Institute of Technology. Data used are publicly available online (https://rbsp-ect.lanl.gov/data_pub/), https://emfisis.physics.uiowa.edu/, http://www.space.umn.edu/rbspefw-data/, and http://rbspice.ftecs.com/.

Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.

Keywords

  • dispersive Alfven waves
  • geomagnetic storms
  • inner magnetosphere
  • ion outflow
  • oxygen ions
  • substorms

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