BGS Hosted Metadata
Global morphology of chorus waves in the outer radiation belt and the effect of geomagnetic activity and fpe/fce
Whistler-mode chorus waves play a key role in driving radiation belt dynamics by enabling both acceleration of electrons to relativistic energies as well as their loss into the atmosphere via pitch-angle scattering. The ratio between the electron plasma frequency (fpe) and the electron gyrofrequency (fce) significantly influences the efficiency of these processes, with electron acceleration being most effective during periods of low fpe/fce. In this study, a combined total of approximately 24.5 years of THEMIS wave data are analyzed to show how chorus wave intensity and spatial location vary with relative frequency, geomagnetic activity and fpe/fce. Results demonstrate that the strongest chorus emissions are observed during active conditions. At these times, equatorial chorus at low relative frequencies (flhr<f<0.1fce) is strongest when fpe/fce is high (fpe/fce>10) primarily in the region 5<L*<8, from 22:00-12:00 MLT. In sharp contrast at high relative frequencies (0.5fce<f<0.7fce), the equatorial chorus is strongest when fpe/fce is low (fpefce<6) mainly in the region 4<L*<6 from 21:00-09:00 MLT. At intermediate relative frequencies (0.3fce<f<0.4fce), equatorial chorus is strongest in the region 3.5<L*<8 from 21:00-12:00 MLT. In the off-equatorial region the strongest waves are seen in the frequency range (0.1fce<f<0.3fce) between 5<L*<8 and 06:00-15:00 MLT and again are mostly independent of fpe/fce. We show that the location of the strongest waves can be largely explained in terms of the source electrons being in the required energy range for resonance and the absence of Landau damping and highlight the regions where electron acceleration to relativistic energies is likely to be mostly significant.
Simple
- Date (Creation)
- 2026-01-09
- Date (Revision)
- 2026-01-09
- Date (Publication)
- 2026-01-09
- Date (released)
- 2026-01-09
- Edition
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1.0
- Unique resource identifier
- https://doi.org/10.5285/5586a319-fa57-4bb6-af3a-3746cd643c0d
- Codespace
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doi
- Unique resource identifier
- GB/NERC/BAS/PDC/02134
- Codespace
- Other citation details
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Please cite this item as: Bunting, K., Meredith, N., Bortnik, J., Ma, Q., Matsuura, R., & Shen, X. (2026). Global morphology of chorus waves in the outer radiation belt and the effect of geomagnetic activity and fpe/fce (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/5586a319-fa57-4bb6-af3a-3746cd643c0d
- Credit
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No credit.
- Status
- Completed
- Point of contact
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Organisation name Individual name Electronic mail address Role British Antarctic Survey Bunting, Kaine
Author British Antarctic Survey Meredith, Nigel
Author UCLA Space institute
Bortnik, Jacob
Author UCLA
Ma, Qianli
Author UCLA
Matsuura, Ryoma
Author Boston University
Shen, Xiao-Chen
Author NERC EDS UK Polar Data Centre Point of contact
- Maintenance and update frequency
- As needed
- Maintenance note
- Completed
- Theme
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Radiation belts
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Wave-particle interaction
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Whistler-mode chorus
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- Place
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Global
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GEMET - INSPIRE themes, version 1.0
- Access constraints
- Other restrictions
- Other constraints
- no limitations to public access
- Access constraints
- Other restrictions
- Other constraints
- no limitations
- Use constraints
- License
- Other constraints
- This dataset is supplied under the Open Government Licence v3.0: https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/
- Unique resource identifier
- url
- Codespace
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url
- Association Type
- Cross reference
- Spatial representation type
- Text, table
- Language
- English
- Character set
- UTF8
- Topic category
-
- Geoscientific information
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- Supplemental Information
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It is recommended that careful attention be paid to the contents of any data, and that the author be contacted with any questions regarding appropriate use. If you find any errors or omissions, please report them to polardatacentre@bas.ac.uk.
- Title
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European Petroleum Survey Group (EPSG) Geodetic Parameter Registry
- Date (Publication)
- 2008-11-12
- Cited responsible party
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Organisation name Individual name Electronic mail address Role European Petroleum Survey Group
Publisher
- Unique resource identifier
- urn:ogc:def:crs:EPSG::3031
- Version
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6.18.3
Distributor
- Distributor contact
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Organisation name Individual name Electronic mail address Role NERC EDS UK Polar Data Centre Distributor
- Units of distribution
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bytes
- Transfer size
- 1
- OnLine resource
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Protocol Linkage Name WWW:LINK-1.0-http--link
http://ramadda.data.bas.ac.uk/repository/entry/show?entryid=5586a319-fa57-4bb6-af3a-3746cd643c0d Get Data
- Hierarchy level
- Dataset
- Statement
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Methodology:
The data used in this study were collected by the NASA Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft. Specifically, we primarily use magnetic (fff) wave data. This data is publicly available at http://themis.ssl.berkeley edu/data/themis. Full details of the subsequent analysis are given in Bunting et al. (2025)
Data collection:
THEMIS data is used from the THEMIS -A, -D and -E satellites. THEMIS high resolution (fff) data is the fast Fourier transform of magnetic variations observed by the search coil magnetometer on board. The Fluxgate magnetometer gives the background magnetic field strength.
Data quality:
THEMIS data have been calibrated and quality-controlled prior to release.
Metadata
- File identifier
- 5586a319-fa57-4bb6-af3a-3746cd643c0d XML
- Metadata language
- English
- Character set
- UTF8
- Hierarchy level
- Dataset
- Hierarchy level name
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dataset
- Date stamp
- 2026-01-09
- Metadata standard name
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ISO 19115 Geographic Information - Metadata
- Metadata standard version
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ISO 19115:2003(E)
- Metadata author
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Organisation name Individual name Electronic mail address Role NERC EDS UK Polar Data Centre Point of contact
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