Modeling radiation belt dynamics using a 3‐D layer method code

Wang, C.; Tao, X.; Zhang, Y.; Teng, Shang‐Hua; Albert, J. M.; Chan, A. A.; Li, W.; Ni, Binbin; Lu, Quanming; Wang, S.

doi:10.1002/2017ja024143

Cited by 16 publications

(16 citation statements)

References 90 publications

(137 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Xiao et al (2014) calculated drift and bounce-averaged diffusion coefficients based on observed chorus spectra and used them in numerical simulations to demonstrate that the observed lower-band chorus waves could cause the observed increase in electron fluxes within 15 hr. Wang et al (2017) concluded that the rapid enhancement of radiation belt flux resulted from the combination of transport by radial diffusion of a seed electron population and subsequent local acceleration driven by chorus waves, and Ma et al (2018), who incorporated both local electron heating by chorus waves and radial transport in their simulation, concluded that resonant interaction with chorus waves was the dominant process that accounted for the electron flux enhancement, particularly near the location of the flux peak. Figure 16a shows a sudden jump in solar wind pressure associated with an interplanetary shock near 06:00 UT on 17 March from~1 nPa to over 7 nPa.…”

Section: Stormtime Enhancement: 17-19 March 2013mentioning

confidence: 99%

EMIC Wave Events During the Four GEM QARBM Challenge Intervals

et al. 2018

Self Cite

View full text Add to dashboard Cite

This paper presents observations of electromagnetic ion cyclotron (EMIC) waves from multiple data sources during the four Geospace Environment Modeling challenge events in 2013 selected by the Geospace Environment Modeling Quantitative Assessment of Radiation Belt Modeling focus group: 17 and 18 March (stormtime enhancement), 31 May to 2 June (stormtime dropout), 19 and 20 September (nonstorm enhancement), and 23–25 September (nonstorm dropout). Observations include EMIC wave data from the Van Allen Probes, Geostationary Operational Environmental Satellite, and Time History of Events and Macroscale Interactions during Substorms spacecraft in the near‐equatorial magnetosphere and from several arrays of ground‐based search coil magnetometers worldwide, as well as localized ring current proton precipitation data from low‐altitude Polar Operational Environmental Satellite spacecraft. Each of these data sets provides only limited spatial coverage, but their combination shows consistent occurrence patterns and reveals some events that would not be identified as significant using near‐equatorial spacecraft alone. Relativistic and ultrarelativistic electron flux observations, phase space density data, and pitch angle distributions based on data from the Relativistic Electron‐Proton Telescope and Magnetic Electron Ion Spectrometer instruments on the Van Allen Probes during these events show two cases during which EMIC waves are likely to have played an important role in causing major flux dropouts of ultrarelativistic electrons, particularly near L* ~4.0. In three other cases, identifiable smaller and more short‐lived dropouts appeared, and in five other cases, these waves evidently had little or no effect.

show abstract

Section: Stormtime Enhancement: 17-19 March 2013mentioning

confidence: 99%

EMIC Wave Events During the Four GEM QARBM Challenge Intervals

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…The selected events were “St. Patrick's Day” storm time enhancement: 17 March 2013 through 19 March 2013 (e.g., Boyd et al, ; Hudson et al, ; Z. Li et al, ; W. Li et al, ; Ma et al, ; Olifer et al, ; Shprits et al, ; Ukhorskiy et al, ; Wang et al, ; Xiao et al, ). “Children's Day” storm time dropout: 31 May 2013 through 3 June 2013 (e.g., Clilverd et al, ; Kang et al, ). “International Talk Like a Pirate Day” nonstorm enhancement: 19 September 2013 through 21 September 2013 (e.g., Ma et al, ; Pakhotin et al, ). “National Punctuation Day” nonstorm dropout: 23 September 2013 through 26 September 2013 (e.g., Capannolo et al, ; Pakhotin et al, ; Su et al, ). A key part of the challenge activity was the collection—in publicly accessible cloud storage—of supporting data, especially of the type used for setting model boundary conditions or incorporating physical processes. As the community continues to move toward open data practices this type of activity will become less necessary, but it proved to be a great community resource for modelers engaging in the FG.…”

Section: Rb Dropout and Rb Buildup Challengesmentioning

confidence: 99%

Quantitative Assessment of Radiation Belt Modeling

Albert

et al. 2019

JGR Space Physics

Self Cite

View full text Add to dashboard Cite

The “Quantitative Assessment of Radiation Belt Modeling” focus group was in place at Geospace Environment Modeling from 2014 to 2018. The overarching goals of this focus group were to bring together the current state‐of‐the‐art models for the acceleration, transport, and loss processes in Earth's radiation belts; develop event‐specific and global inputs of wave, plasma, and magnetic field to drive these models; and combine all these components to achieve a quantitative assessment of radiation belt modeling by validating against contemporary radiation belt measurements. This article briefly reviews the current understanding of radiation belt dynamics and related modeling efforts, summarizes the activities and accomplishments of the focus group, and discusses future directions.

show abstract

“…Present 3‐D radiation belt models generally either set the minimum energy to a constant value throughout the calculation region (e.g., Tu et al, ; Wang et al, ) or the minimum energy is defined by a line of constant first adiabatic invariant, μ (e.g., Albert et al, ; Glauert et al, ). Here we formulate the 90° electron flux at energies following a line of first adiabatic invariant to explore using the presented methods to generate low‐energy boundaries for models like the British Antarctic Survey (BAS) Radiation Belt Model (Glauert et al, ).…”

Section: Using the Poes Data To Form A Low‐energy Boundary Conditionmentioning

confidence: 99%

Determination of the Equatorial Electron Differential Flux From Observations at Low Earth Orbit

et al. 2018

View full text Add to dashboard Cite

Variations in the high-energy relativistic electron flux of the radiation belts depend on transport, acceleration, and loss processes, and importantly on the lower-energy seed population. However, data on the seed population is limited to a few satellite missions. Here we present a new method that utilizes data from the Medium Energy Proton/Electron Detector on board the low-altitude Polar Operational Environmental Satellites to retrieve the seed population at a pitch angle of 90 ∘ . The integral flux values measured by Medium Energy Proton/Electron Detector relate to a low equatorial pitch angle and were converted to omnidirectional flux using parameters obtained from fitting one or two sin N functions to pitch angle distributions given by three and a half years of Van Allen Probes data. Two methods to convert from integral to differential flux are explored. One utilizes integral and differential flux energy distributions from the AE9 model, the second employs an iterative fitting approach based on a Reverse Monte Carlo (RMC) method. The omnidirectional differential flux was converted to an equatorial pitch angle of 90 ∘ , again using statistical pitch angle distributions from Van Allen Probe data. We validate the resulting 90 ∘ flux for 100-to 600-keV electrons against measurements from the Van Allen Probes and show an average agreement within a factor of 4 for L* > 3.7. The resulting data set offers a high time resolution, across multiple magnetic local time planes, and may be used to formulate event-specific low-energy boundary conditions for radiation belt models.Prior to 2012, the National Oceanic and Atmospheric Administration (NOAA) Polar Operational Environmental Satellites (POES) were operational. The POES satellites carry the Space Environment Monitor (SEM-2) Medium Energy Proton and Electron Detector (MEPED), which measures >30-, >100-, and >300-keV electron data at a 2-s resolution (Evans & Greer, 2004). Launched in May 1998, NOAA15 was the first POES satellite to carry SEM-2. Since then, a further four POES satellites have been launched and, to date, three POES satellites are still sampling data. POES MEPED measurements are therefore available for more than the last 19 years, providing a wealth of information on seed population electrons. Operating in a ∼98.5 ∘ inclination low Earth orbit, these satellites sample the electron flux across a broad range of the magnetic coordinate L* (Roederer, 1970). During quiet conditions, POES coverage can extend from L* < 1.3 to L* > 8.5; a larger L* range than possible with the Van Allen Probes. Due to the orbit, the POES satellites offer very rapid measurements of the radiation belts and, with up to five satellites sampling the region, provide data in multiple magnetic local time (MLT) planes. However, one of the major limitations of the POES data set for studying the seed population is that the electron channels of MEPED only supply integral flux. Additionally, measurements are taken near the bottom of magnetic field lines, and the electron flux sampled is cons...

show abstract

Modeling radiation belt dynamics using a 3‐D layer method code

Cited by 16 publications

References 90 publications

EMIC Wave Events During the Four GEM QARBM Challenge Intervals

EMIC Wave Events During the Four GEM QARBM Challenge Intervals

Quantitative Assessment of Radiation Belt Modeling

Determination of the Equatorial Electron Differential Flux From Observations at Low Earth Orbit

Contact Info

Product

Resources

About