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Ukhorskiy AY, Sitnov MI, Millan RM, Kress BT, Fennell JF, Claudepierre SG, Barnes RJ. Global storm time depletion of the outer electron belt. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2015; 120:2543-2556. [PMID: 27656334 PMCID: PMC5014085 DOI: 10.1002/2014ja020645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 03/04/2015] [Accepted: 03/04/2015] [Indexed: 06/06/2023]
Abstract
The outer radiation belt consists of relativistic (>0.5 MeV) electrons trapped on closed trajectories around Earth where the magnetic field is nearly dipolar. During increased geomagnetic activity, electron intensities in the belt can vary by orders of magnitude at different spatial and temporal scales. The main phase of geomagnetic storms often produces deep depletions of electron intensities over broad regions of the outer belt. Previous studies identified three possible processes that can contribute to the main-phase depletions: adiabatic inflation of electron drift orbits caused by the ring current growth, electron loss into the atmosphere, and electron escape through the magnetopause boundary. In this paper we investigate the relative importance of the adiabatic effect and magnetopause loss to the rapid depletion of the outer belt observed at the Van Allen Probes spacecraft during the main phase of 17 March 2013 storm. The intensities of >1 MeV electrons were depleted by more than an order of magnitude over the entire radial extent of the belt in less than 6 h after the sudden storm commencement. For the analysis we used three-dimensional test particle simulations of global evolution of the outer belt in the Tsyganenko-Sitnov (TS07D) magnetic field model with an inductive electric field. Comparison of the simulation results with electron measurements from the Magnetic Electron Ion Spectrometer experiment shows that magnetopause loss accounts for most of the observed depletion at L>5, while at lower L shells the depletion is adiabatic. Both magnetopause loss and the adiabatic effect are controlled by the change in global configuration of the magnetic field due to storm time development of the ring current; a simulation of electron evolution without a ring current produces a much weaker depletion.
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Affiliation(s)
- A. Y. Ukhorskiy
- Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - M. I. Sitnov
- Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - R. M. Millan
- Department of Physics and AstronomyDartmouth CollegeHanoverNew HampshireUSA
| | - B. T. Kress
- Cooperative Institute for Research in Environmental SciencesUniversity of Colorado at BoulderBoulderColoradoUSA
| | | | | | - R. J. Barnes
- Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
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Kim KC, Shprits Y, Subbotin D, Ni B. Relativistic radiation belt electron responses to GEM magnetic storms: Comparison of CRRES observations with 3-D VERB simulations. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011ja017460] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Shprits Y, Daae M, Ni B. Statistical analysis of phase space density buildups and dropouts. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011ja016939] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kim KC, Lee DY, Shprits Y, Kim HJ, Lee E. Electron flux changes in the outer radiation belt by radial diffusion during the storm recovery phase in comparison with the fully adiabatic evolution. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016642] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Kyung-Chan Kim
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
| | - Dae-Young Lee
- Department of Astronomy and Space Science; Chungbuk National University; Cheongju South Korea
| | - Yuri Shprits
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
- Department of Atmospheric and Oceanic Science; University of California; Los Angeles California USA
| | - Hee-Jeong Kim
- Department of Atmospheric and Oceanic Science; University of California; Los Angeles California USA
| | - Ensang Lee
- School of Space Research; Kyung-Hee University; Yongin South Korea
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Matsumura C, Miyoshi Y, Seki K, Saito S, Angelopoulos V, Koller J. Outer radiation belt boundary location relative to the magnetopause: Implications for magnetopause shadowing. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016575] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- C. Matsumura
- Solar-Terrestrial Environment Laboratory; Nagoya University; Nagoya Japan
| | - Y. Miyoshi
- Solar-Terrestrial Environment Laboratory; Nagoya University; Nagoya Japan
| | - K. Seki
- Solar-Terrestrial Environment Laboratory; Nagoya University; Nagoya Japan
| | - S. Saito
- Solar-Terrestrial Environment Laboratory; Nagoya University; Nagoya Japan
| | | | - J. Koller
- Los Alamos National Laboratory; Los Alamos New Mexico USA
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Ni B, Shprits Y, Hartinger M, Angelopoulos V, Gu X, Larson D. Analysis of radiation belt energetic electron phase space density using THEMIS SST measurements: Cross-satellite calibration and a case study. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010ja016104] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Binbin Ni
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - Yuri Shprits
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
| | - Michael Hartinger
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
- Department of Earth and Space Sciences; University of California; Los Angeles California USA
| | - Vassilis Angelopoulos
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
- Department of Earth and Space Sciences; University of California; Los Angeles California USA
| | - Xudong Gu
- Department of Space Physics; Wuhan University; Wuhan, Hubei China
| | - Davin Larson
- Space Sciences Laboratory; University of California; Berkeley California USA
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Saito S, Miyoshi Y, Seki K. A split in the outer radiation belt by magnetopause shadowing: Test particle simulations. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja014738] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- S. Saito
- Solar-Terrestrial Environment Laboratory; Nagoya University; Nagoya Japan
| | - Y. Miyoshi
- Solar-Terrestrial Environment Laboratory; Nagoya University; Nagoya Japan
| | - K. Seki
- Solar-Terrestrial Environment Laboratory; Nagoya University; Nagoya Japan
- Institute for Advanced Research; Nagoya University; Nagoya Japan
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Morley SK, Friedel RHW, Spanswick EL, Reeves GD, Steinberg JT, Koller J, Cayton T, Noveroske E. Dropouts of the outer electron radiation belt in response to solar wind stream interfaces: global positioning system observations. Proc Math Phys Eng Sci 2010. [DOI: 10.1098/rspa.2010.0078] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We present a statistical study of relativistic electron counts in the electron radiation belt across a range of drift shells (L*>4) combining data from nine combined X-ray dosimeters (CXD) on the global positioning system (GPS) constellation. The response of the electron counts as functions of time, energy and drift shell are examined statistically for 67 solar wind stream interfaces (SIs); two-dimensional superposed epoch analysis is performed with the CXD data. For these epochs we study the radiation belt dropouts and concurrent variations in key geophysical parameters.
At higher L* we observe a tendency for a gradual drop in the electron counts over the day preceding the SI, consistent with outward diffusion and magnetopause shadowing. At all L*, dropouts occur with a median time scale of ≃7 h and median counts fall by 0.4–1.8 orders of magnitude. The central tendencies of radiation belt dropout and recovery depend on both L* and energy. For ≃70 per cent of epochs Sym-H more than −30 nT, yet only three of 67 SIs did not have an associated dropout in the electron data. Statistical maps of electron precipitation suggest that chorus-driven relativistic electron microbursts might be major contributors to radiation belt losses under high-speed stream driving.
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Affiliation(s)
- Steven K. Morley
- Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Reiner H. W. Friedel
- Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Emma L. Spanswick
- Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM, USA
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - Geoffrey D. Reeves
- Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - John T. Steinberg
- Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Josef Koller
- Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Thomas Cayton
- Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Evan Noveroske
- Space Data Systems, Los Alamos National Laboratory, Los Alamos, NM, USA
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Kim KC, Lee DY, Kim HJ, Lee ES, Choi CR. Numerical estimates of drift loss and Dst effect for outer radiation belt relativistic electrons with arbitrary pitch angle. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja014523] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Kyung Chan Kim
- Department of Astronomy and Space Science; Chungbuk National University; Chungbuk South Korea
| | - D.-Y. Lee
- Department of Astronomy and Space Science; Chungbuk National University; Chungbuk South Korea
| | - H.-J. Kim
- Department of Atmospheric Sciences; University of California; Los Angeles California USA
| | - E. S. Lee
- Space Sciences Laboratory; University of California; Berkeley USA
| | - C. R. Choi
- Department of Physics; Korea Advanced Institute of Science and Technology; Daejeon South Korea
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Li LY, Cao JB, Zhou GC, Li X. Statistical roles of storms and substorms in changing the entire outer zone relativistic electron population. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009ja014333] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- L. Y. Li
- State Key Laboratory for Space Weather, Center for Space Science and Applied Research; Chinese Academy of Sciences; Beijing China
| | - J. B. Cao
- School of Astronautics; Beijing University of Aeronautics and Astronautics; Beijing China
| | - G. C. Zhou
- State Key Laboratory for Space Weather, Center for Space Science and Applied Research; Chinese Academy of Sciences; Beijing China
| | - X. Li
- Laboratory for Atmospheric and Space Physics; University of Colorado at Boulder; Boulder Colorado USA
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