logo

SCIENCE CHINA Technological Sciences, Volume 61 , Issue 2 : 212-218(2018) https://doi.org/10.1007/s11431-017-9067-y

Butterfly distribution of Earth's radiation belt relativistic electrons induced by dayside chorus

More info
  • ReceivedMar 27, 2017
  • AcceptedMay 11, 2017
  • PublishedSep 12, 2017

Abstract

Previous theoretical studies have shown that dayside chorus can produce butterfly distribution of energetic electrons in the Earth's radiation belts by preferentially accelerating medium pitch angle electrons, but this requires the further confirmation from high-resolution satellite observation. Here, we report correlated Van Allen Probes data on wave and particle during the 11–13 April, 2014 geomagnetic storm. We find that a butterfly pitch angle distribution of relativistic electrons is formed around the location $L=4.52$, corresponding to the presence of enhanced dayside chorus. Using a Gaussian distribution fit to the observed chorus spectra, we calculate the bounce-averaged diffusion rates and solve two-dimensional Fokker-Planck equation. Numerical results demonstrate that acceleration by dayside chorus can yield the electron flux evolution both in the energy and butterfly pitch angle distribution comparable to the observation, providing a further evidence for the formation of butterfly distribution of relativistic electrons driven by very low frequency (VLF) plasma waves.


Acknowledgment

This work was supported by the National Natural Science Foundation of China (Grant Nos. 41531072, 41404130, 41504125 rm 41674166). We appreciate the Van Allen Probes REPT team for providing relativistic electron data.


References

[1] Li L. Combined acceleration of electrons by whistler-mode and compressional ULF turbulences near the geosynchronous orbit. J Geophys Res, 2005, 110: A03203 CrossRef ADS Google Scholar

[2] Summers D, Thorne R M, Xiao F. Relativistic theory of wave-particle resonant diffusion with application to electron acceleration in the magnetosphere. J Geophys Res, 1998, 103: 20487-20500 CrossRef ADS Google Scholar

[3] Summers D, Ma C, Meredith N P. Model of the energization of outer-zone electrons by whistler-mode chorus during the October 9, 1990 geomagnetic storm. Geophys Res Lett, 2002, 29: 27-1-27-4 CrossRef ADS Google Scholar

[4] Horne R B. Timescale for radiation belt electron acceleration by whistler mode chorus waves. J Geophys Res, 2005, 110: A03225 CrossRef ADS Google Scholar

[5] Tao X, Chan A A, Albert J M. Stochastic modeling of multidimensional diffusion in the radiation belts. J Geophys Res, 2008, 113: A07212 CrossRef ADS Google Scholar

[6] Thorne R M, Li W, Ni B. Rapid local acceleration of relativistic radiation-belt electrons by magnetospheric chorus. Nature, 2013, 504: 411-414 CrossRef PubMed ADS Google Scholar

[7] Xiao F, Su Z, Zheng H. Modeling of outer radiation belt electrons by multidimensional diffusion process. J Geophys Res, 2009, 114: A03201 CrossRef ADS Google Scholar

[8] Xiao F, Su Z, Zheng H. Three-dimensional simulations of outer radiation belt electron dynamics including cross-diffusion terms. J Geophys Res, 2010, 115: A05216 CrossRef ADS Google Scholar

[9] Ni B, Bortnik J, Thorne R M. Resonant scattering and resultant pitch angle evolution of relativistic electrons by plasmaspheric hiss. J Geophys Res Space Phys, 2013, 118: 7740-7751 CrossRef ADS Google Scholar

[10] Ni B, Cao X, Zou Z. Resonant scattering of outer zone relativistic electrons by multiband EMIC waves and resultant electron loss time scales. J Geophys Res Space Phys, 2015, 120: 7357-7373 CrossRef ADS Google Scholar

[11] Su Z, Gao Z, Zhu H. Nonstorm time dropout of radiation belt electron fluxes on 24 September 2013. J Geophys Res Space Phys, 2016, 121: 6400-6416 CrossRef ADS Google Scholar

[12] Wang B, Su Z, Zhang Y. Nonlinear Landau resonant scattering of near equatorially mirroring radiation belt electrons by oblique EMIC waves. Geophys Res Lett, 2016, 43: 3628-3636 CrossRef ADS Google Scholar

[13] Wang G, Su Z, Zheng H. Nonlinear fundamental and harmonic cyclotron resonant scattering of radiation belt ultrarelativistic electrons by oblique monochromatic EMIC waves. J Geophys Res Space Phys, 2017, 108: 1928-1945 CrossRef ADS Google Scholar

[14] Horne R B, Thorne R M, Glauert S A. Electron acceleration in the Van Allen radiation belts by fast magnetosonic waves. Geophys Res Lett, 2007, 34: L17107 CrossRef ADS Google Scholar

[15] Li J, Ni B, Ma Q. Formation of energetic electron butterfly distributions by magnetosonic waves via Landau resonance. Geophys Res Lett, 2016, 43: 3009-3016 CrossRef ADS Google Scholar

[16] Xiao F, Yang C, Su Z. Wave-driven butterfly distribution of Van Allen belt relativistic electrons. Nat Commun, 2015, 6: 8590 CrossRef PubMed ADS Google Scholar

[17] Ni B, Zou Z, Li X. Occurrence characteristics of outer zone relativistic electron butterfly distribution: A survey of Van Allen Probes REPT measurements. Geophys Res Lett, 2016, 43: 5644-5652 CrossRef ADS Google Scholar

[18] Mauk B H, Fox N J, Kanekal S G. Science Objectives and Rationale for the Radiation Belt Storm Probes Mission. Space Sci Rev, 2013, 179: 3-27 CrossRef ADS Google Scholar

[19] Blake J B, Carranza P A, Claudepierre S G. The Magnetic Electron Ion Spectrometer (MagEIS) Instruments Aboard the Radiation Belt Storm Probes (RBSP) Spacecraft. Space Sci Rev, 2013, 179: 383-421 CrossRef ADS Google Scholar

[20] Kletzing C A, Kurth W S, Acuna M. The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) on RBSP. Space Sci Rev, 2013, 179: 127-181 CrossRef ADS Google Scholar

[21] Wygant J R, Bonnell J W, Goetz K. The Electric Field and Waves Instruments on the Radiation Belt Storm Probes Mission. Space Sci Rev, 2013, 179: 183-220 CrossRef ADS Google Scholar

[22] Xiao F, Zhou Q, Zheng H. Whistler instability threshold condition of energetic electrons by kappa distribution in space plasmas. J Geophys Res, 2006, 111: A08208 CrossRef ADS Google Scholar

[23] Summers D, Tang R, Thorne R M. Limit on stably trapped particle fluxes in planetary magnetospheres. J Geophys Res, 2009, 114: A10210 CrossRef ADS Google Scholar

[24] He Y, Xiao F, Zhou Q. Van Allen Probes observation and modeling of chorus excitation and propagation during weak geomagnetic activities. J Geophys Res Space Phys, 2015, 120: 6371-6385 CrossRef ADS Google Scholar

[25] Xiao F, Thorne R M, Summers D. Instability of electromagnetic R-mode waves in a relativistic plasma. Phys Plasmas, 1998, 5: 2489-2497 CrossRef ADS Google Scholar

[26] Li W, Thorne R M, Angelopoulos V. Global distribution of whistler-mode chorus waves observed on the THEMIS spacecraft. Geophys Res Lett, 2009, 36: L09104 CrossRef ADS Google Scholar

[27] Jordanova V K, Thorne R M, Li W. Excitation of whistler mode chorus from global ring current simulations. J Geophys Res, 2010, 115: A00F10 CrossRef ADS Google Scholar

[28] Yang Q W, Yang C, He Y H. Magnetospheric chorus wave instability induced by relativistic Kappa-type distributions. Sci China Technol Sci, 2016, 59: 1739-1745 CrossRef Google Scholar

[29] Baker D N, Kanekal S G, Hoxie V C. The Relativistic Electron-Proton Telescope (REPT) Instrument on Board the Radiation Belt Storm Probes (RBSP) Spacecraft: Characterization of Earth's Radiation Belt High-Energy Particle Populations. Space Sci Rev, 2013, 179: 337-381 CrossRef ADS Google Scholar

[30] Tsurutani B T, Verkhoglyadova O P, Lakhina G S. Properties of dayside outer zone chorus during HILDCAA events: Loss of energetic electrons. J Geophys Res, 2009, 114: A03207 CrossRef ADS Google Scholar

[31] Lyons L R, Thorne R M, Kennel C F. Pitch-angle diffusion of radiation belt electrons within the plasmasphere. J Geophys Res, 1972, 77: 3455-3474 CrossRef ADS Google Scholar

[32] Vasyliunas V M. A survey of low-energy electrons in the evening sector of the magnetosphere with OGO 1 and OGO 3. J Geophys Res, 1968, 73: 2839-2884 CrossRef ADS Google Scholar

[33] Vi?as A F. Dispersion characteristics for plasma resonances of Maxwellian and Kappa distribution plasmas and their comparisons to the IMAGE/RPI observations. J Geophys Res, 2005, 110: A06202 CrossRef ADS Google Scholar

[34] Xiao F, Shen C, Wang Y. Energetic electron distributions fitted with a relativistic kappa-type function at geosynchronous orbit. J Geophys Res, 2008, 113: A05203 CrossRef ADS Google Scholar

[35] Mourenas D, Artemyev A V, Agapitov O V. Consequences of geomagnetic activity on energization and loss of radiation belt electrons by oblique chorus waves. J Geophys Res Space Phys, 2014, 119: 2775-2796 CrossRef ADS Google Scholar

[36] Artemyev A, Agapitov O, Mourenas D. Oblique Whistler-Mode Waves in the Earth's Inner Magnetosphere: Energy Distribution, Origins, and Role in Radiation Belt Dynamics. Space Sci Rev, 2016, 200: 261-355 CrossRef ADS Google Scholar

[37] Li W, Shprits Y Y, Thorne R M. Dynamic evolution of energetic outer zone electrons due to wave-particle interactions during storms. J Geophys Res, 2007, 112: A10220 CrossRef ADS Google Scholar

[38] Shprits Y Y, Meredith N P, Thorne R M. Parameterization of radiation belt electron loss timescales due to interactions with chorus waves. Geophys Res Lett, 2007, 34: L11110 CrossRef ADS Google Scholar

[39] Sheeley B W, Moldwin M B, Rassoul H K. An empirical plasmasphere and trough density model: CRRES observations. J Geophys Res, 2001, 106: 25631-25641 CrossRef ADS Google Scholar

[40] Yang C, Su Z, Xiao F. Rapid flattening of butterfly pitch angle distributions of radiation belt electrons by whistler-mode chorus. Geophys Res Lett, 2016, 43: 8339-8347 CrossRef ADS Google Scholar

[41] Artemyev A V, Agapitov O V, Mourenas D. Wave energy budget analysis in the Earth's radiation belts uncovers a missing energy. Nat Commun, 2015, 6: 8143 CrossRef PubMed ADS Google Scholar

[42] Reeves G D, Spence H E, Henderson M G. Electron Acceleration in the Heart of the Van Allen Radiation Belts. Science, 2013, 341: 991-994 CrossRef PubMed ADS Google Scholar

[43] Xiao F, Yang C, He Z. Chorus acceleration of radiation belt relativistic electrons during March 2013 geomagnetic storm. J Geophys Res Space Phys, 2014, 119: 3325-3332 CrossRef ADS Google Scholar

  • Figure 1

    (Color online) Van Allen Probes (A and B) data.a) The Dst and AE indexes; (b) and (c) energetic electron differential fluxes as a function of $L$; (d) and (e) magnetic spectral intensity of chorus and MS waves. The solid, dashed and dot-dashed lines denote the 0.1$f_{\rm~ce}$, 0.5$f_{\rm~ce}$ and $f_{\rm~ce}$, respectively. (f) and (g) Relativistic electron differential fluxes as a function of $L$. The vertical dotted lines indicate the simulation period.

  • Figure 2

    (Color online) (a) and (b) Magnetic and electric spectral density of dayside chorus and MS waves; (c) wave normal angle; (d) wave ellipticity.

  • Figure 3

    (Color online) (a) The Gaussian distribution fit (solid) to the observed (dotted) magnetic field spectral density at the indicated 4-min interval, with the corresponding fitting parameters (shown); (b) the time-frequency spectrogram in chorus magnetic field spectral density at the indicated 6-sec interval.

  • Figure 4

    (Color online) Formation of butterfly distribution.a)–(c) Normal/flat-top and (d)–(f) butterfly distributions for different indicated energies (1.5–2.1 MeV) electrons during a 20-min interval.

  • Figure 5

    (Color online) (a) Bounce-averaged pitch angle; (b) momentum and (c) cross diffusion rates (in unit of $\rm~s^{-1}$) for resonant interactions between dayside chorus and electrons; (d) the sign of cross diffusion rate.

  • Figure 6

    (Color online) Comparison of simulation results with observations.a) and (b) Observed evolution of the relativistic electron fluxes as a function of pitch angle at the same location (shown inside panels); (c) and (d) starting with an initial condition representative of relativistic electrons (a), we show the simulated evolution of relativistic (1.5–2.1 MeV) electrons induced by dayside chorus.

Copyright 2020  CHINA SCIENCE PUBLISHING & MEDIA LTD.  中国科技出版传媒股份有限公司  版权所有

京ICP备14028887号-23       京公网安备11010102003388号