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Duration of Individual Relativistic Electron Microbursts: A Probe Into Their Scattering Mechanism

https://doi.org/10.1029/2021GL093879

Shumko, M. ; Blum, L. W. ; Crew, A. B. ( September 2021 , Geophysical Research Letters)

Abstract
We used the Solar Anomalous and Magnetospheric Particle Explorer to identify and quantify the duration of relativistic,MeV, electron microbursts. A typical relativistic microburst has amillisecond (ms) duration, and the interquartile range of the duration distribution is 70–140 ms. We investigated trends in the microburst duration as a function of geomagnetic activity, L‐shell, and magnetic local time (MLT). The clearest trend is in MLT: the median microburst duration doubles from 75 milliseconds at midnight to 140 milliseconds noon MLT. This trend is similar to the whistler mode chorus rising tone element duration trend, suggesting a possible relationship.

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Estimating the Impacts of Radiation Belt Electrons on Atmospheric Chemistry Using FIREBIRD II and Van Allen Probes Observations

https://doi.org/10.1029/2020JD033098

Duderstadt, K. A. ; Huang, C. ‐L. ; Spence, H. E. ; Smith, S. ; Blake, J. B. ; Crew, A. B. ; Johnson, A. T. ; Klumpar, D. M. ; Marsh, D. R. ; Sample, J. G. ; et al ( March 2021 , Journal of Geophysical Research: Atmospheres)

Abstract
This study considers the impact of electron precipitation from Earth's radiation belts on atmospheric composition using observations from the NASA Van Allen Probes and NSF Focused Investigations of Relativistic Electron Burst Intensity, Range, and Dynamics (FIREBIRD II) CubeSats. Ratios of electron flux between the Van Allen Probes (in near‐equatorial orbit in the radiation belts) and FIREBIRD II (in polar low Earth orbit) during spacecraft conjunctions (2015–2017) allow an estimate of precipitation into the atmosphere. Total Radiation Belt Electron Content, calculated from Van Allen Probes RBSP‐ECT MagEIS data, identifies a sustained 10‐day electron loss event in March 2013 that serves as an initial case study. Atmospheric ionization profiles, calculated by integrating monoenergetic ionization rates across the precipitating electron flux spectrum, provide input to the NCAR Whole Atmosphere Community Climate Model in order to quantify enhancements of atmospheric HO_xand NO_xand subsequent destruction of O₃in the middle atmosphere. Results suggest that current APEEP parameterizations of radiation belt electrons used in Coupled Model Intercomparison Project may underestimate the duration of events as well as higher energy electron contributions to atmospheric ionization and modeled NO_xconcentrations in the mesosphere and upper stratosphere.

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The FIREBIRD-II CubeSat mission: Focused investigations of relativistic electron burst intensity, range, and dynamics

https://doi.org/10.1063/1.5137905

Johnson, A. T. ; Shumko, M. ; Griffith, B. ; Klumpar, D. M. ; Sample, J. ; Springer, L. ; Leh, N. ; Spence, H. E. ; Smith, S. ; Crew, A. ; et al ( March 2020 , Review of Scientific Instruments)
Spatial scale and duration of one microburst region on 13 August 2015: SPATIAL SCALE OF MICROBURSTS 13 AUG 2015

https://doi.org/10.1002/2016JA023752

Anderson, B. R. ; Shekhar, S. ; Millan, R. M. ; Crew, A. B. ; Spence, H. E. ; Klumpar, D. M. ; Blake, J. B. ; O'Brien, T. P. ; Turner, D. L. ( June 2017 , Journal of Geophysical Research: Space Physics)