New Chorus Diffusion Coefficients for Radiation Belt Modelling

Whistler mode chorus is an important magnetospheric wave emission playing a major role in radiation belt dynamics, where it contributes to both the acceleration and loss of relativistic electrons. In this study we compute bounce and drift averaged chorus diffusion coefficients for 3.0 < L* < 6.0, using the TS04 external magnetic field model, taking into account co-located near-equatorial measurements of the wave intensity and fpe/fce, by combining the Van Allen probes measurements with data from a multi-satellite VLF wave database. The variation of chorus wave normal angle with spatial location and fpe/fce is also taken into account. We find that chorus propagating at small wave normal angles has the dominant contribution to the diffusion rates in most MLT sectors. However, in the region 4 <= MLT < 11 high wave normal angles dominate at intermediate pitch angles. In the region 3 < L* < 4, the bounce and drift averaged pitch angle and energy diffusion rates during active conditions are primarily larger than those in our earlier models by up to a factor of 10 depending on energy and pitch angle. Further out, the results are similar. We find that the bounce and drift averaged energy and pitch angle diffusion rates can be significantly larger than the new model in regions of low fpe/fce,eq, where the differences can be up to a factor of 10 depending on energy and pitch angle.

Funding was provided by the Natural Environment Research Council (NERC) Highlight Topic grant NE/P01738X/1 (Rad-Sat) and the NERC grants NE/V00249X/1 (Sat-Risk), NE/R016038/1 and NE/X000389/1.

Date (Creation): 2023-10-19

Date (Revision): 2023-10-19

Date (Publication): 2023-10-19

Date (released): 2023-10-19

Edition: 1.0

Unique resource identifier: https://doi.org/10.5285/fa63faf5-10d6-4c72-8b19-d41941f06812

Codespace: doi

Unique resource identifier: GB/NERC/BAS/PDC/01782

Codespace: https://data.bas.ac.uk/

Unique resource identifier: NE/P01738X/1

Codespace: award

Unique resource identifier: NE/R016038/1

Codespace: award

Unique resource identifier: NE/X000389/1

Codespace: award

Other citation details: Please cite this item as: Wong, J. (2023). New Chorus Diffusion Coefficients for Radiation Belt Modelling (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/fa63faf5-10d6-4c72-8b19-d41941f06812

Credit: No credit.

Status: Completed

Point of contact

Organisation name	Individual name	Electronic mail address	Role
British Antarctic Survey	Wong, Jin-Mann		Author
NERC EDS UK Polar Data Centre		PDCServiceDesk@bas.ac.uk	Point of contact

Maintenance and update frequency: As needed

Maintenance note: Completed

Global Change Master Directory (GCMD) Science Keywords

EARTH SCIENCE > Sun-earth Interactions > Ionosphere/Magnetosphere Dynamics

Theme

Chorus Waves
Electron Diffusion
Radiation Belts

Place

Van Allen Probes: Perigee ~1.1Re, Apogee ~5.8Re, Inclination 10 degrees Van Allen Radiation Belts

GEMET - INSPIRE themes, version 1.0

Atmospheric conditions

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Other constraints: Data supplied under Open Government Licence v3.0

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Language: English

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Climatology, meteorology, atmosphere

Begin date: 2012-11-07

End date: 2019-10-14

Supplemental Information: 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: European Petroleum Survey Group (EPSG) Geodetic Parameter Registry

Date (Publication): 2008-11-12

Cited responsible party

Organisation name	Individual name	Electronic mail address	Role
European Petroleum Survey Group		EPSGadministrator@iogp.org	Publisher

Unique resource identifier: urn:ogc:def:crs:EPSG::3031

Version: 6.18.3

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Organisation name	Individual name	Electronic mail address	Role
NERC EDS UK Polar Data Centre		PDCServiceDesk@bas.ac.uk	Distributor

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Protocol	Linkage	Name
WWW:LINK-1.0-http--link	http://ramadda.data.bas.ac.uk/repository/entry/show?entryid=fa63faf5-10d6-4c72-8b19-d41941f06812	Get Data

Hierarchy level: Dataset

Statement: Methodology:

The data for the figures and generation of the diffusion coefficients come from the EMFISIS instrument on Van Allen Probes RBSP-A available online ( https://emfisis.physics.uiowa.edu/data/index), and the VLF database derived in Meredith et al [2020]. The Kp indices used in this study are available from the NSSDC Omniweb. Full details of the subsequent analysis are given in Wong et al [2023]

Data collection:

We use data from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instruments on board RBSP-A. The EMFISIS Waveform Receivers on RBSP-A measured the sum of the three components of the magnetic power spectral density of the waves in 65 frequency channels, with centre frequencies between 2.13 Hz and 11.24 kHz. We also use density measurements from the EMFISIS High Frequency Receiver which measured the electric field power spectral density in the frequency range 10 kHz to 487 kHz.

The VLF database contains wave data from eight satellites, including approximately 3 years of data from Dynamics Explorer 1 (DE1), 1 year of data from Double Star TC1, 10 years of data from Cluster 1, 8 years of data from each of Time History of Events and Macroscale Interactions during Substorms (THEMIS)-A, THEMIS-D, and THEMIS-E, and 3 years of data from the Van Allen probes RBSP-A and RBSP-B.

Data quality:

The wave data have been calibrated and quality-controlled prior to release. We also omitted data during thruster firing, eclipse and charging times.

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File identifier: fa63faf5-10d6-4c72-8b19-d41941f06812 XML

Metadata language: English

Character set: UTF8

Hierarchy level: Dataset

Hierarchy level name: dataset

Date stamp: 2023-10-19

Metadata standard name: ISO 19115 Geographic Information - Metadata

Metadata standard version: ISO 19115:2003(E)

Metadata author

Organisation name	Individual name	Electronic mail address	Role
NERC EDS UK Polar Data Centre		polardatacentre@bas.ac.uk	Point of contact

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