Hemispheric Distribution of Lower-band Chorus Waves Observed by Van Allen Probes
doi: 10.11728/cjss2020.02.186
-
摘要: Whistler mode chorus waves are important electromagnetic emissions due to their dual roles in acceleration and loss processes of Earth’s radiation belt electrons. A detailed global survey of lower-band chorus is performed using EMFISIS data from Van Allen Probes in near-equatorial orbits. In addition to the confirmation of the positive correlation of chorus wave intensities to geomagnetic activity and dayside-nightside distribution asymmetry of wave amplitude and occurrence probability, the analysis results find that in statistics lower-band chorus emissions exhibit higher wave occurrence rates and larger normalized peak wave frequencies in the magnetically northern hemisphere but somehow stronger peak wave intensities in the magnetically southern hemisphere. While overall the differences between the two magnetically hemispheric distributions tend to be not significant, it is important to establish the magnetically hemispheric distribution profiles of lowerband chorus with respect to L-shell, magnetic local time, and geomagnetic latitude for improved understanding of chorus-induced dynamics of radiation belt electrons.Abstract: Whistler mode chorus waves are important electromagnetic emissions due to their dual roles in acceleration and loss processes of Earth’s radiation belt electrons. A detailed global survey of lower-band chorus is performed using EMFISIS data from Van Allen Probes in near-equatorial orbits. In addition to the confirmation of the positive correlation of chorus wave intensities to geomagnetic activity and dayside-nightside distribution asymmetry of wave amplitude and occurrence probability, the analysis results find that in statistics lower-band chorus emissions exhibit higher wave occurrence rates and larger normalized peak wave frequencies in the magnetically northern hemisphere but somehow stronger peak wave intensities in the magnetically southern hemisphere. While overall the differences between the two magnetically hemispheric distributions tend to be not significant, it is important to establish the magnetically hemispheric distribution profiles of lowerband chorus with respect to L-shell, magnetic local time, and geomagnetic latitude for improved understanding of chorus-induced dynamics of radiation belt electrons.
-
[1] BURTIS W J, HELLIWELL R A. Banded chorus-A new type of VLF radiation observed in the magnetosphere by OGO 1 and OGO 3[J]. J. Geophys. Res., 1969, 74(11):3002-3010 [2] SANTOLÍK O, GURNETT D A, PICKETT J S, et al. Spatio-temporal structure of storm-time chorus[J]. J. Geophys. Res., 2003, 108(A7):1278 [3] TSURUTANI B T, SMITH E J. Postmidnight chorus:a substorm phenomenon[J]. J. Geophys. Res., 1974, 79(1):118-127 [4] LI Wen, THORNE R M, BORTNIK J, et al. Typical properties of rising and falling tone chorus waves[J]. Geophys. Res. Lett., 2011, 38(14):L14103 [5] KOONS H C, ROEDER J L. A survey of equatorial magnetospheric wave activity between 5 and 8 RE[J]. Planet. Space Sci., 1990, 38(10):1335-1341 [6] LI Wen, THORNE R M, ANGELOPOULOS V, et al. Global distribution of whistler-mode chorus waves observed on the THEMIS spacecraft[J]. Geophys. Res. Lett., 2009, 36(9):L09104 [7] LI WEN, BORTNIK J, THORNE R M, et al. Global distribution of wave amplitudes and wave normal angles of chorus waves using THEMIS wave observations[J]. J. Geophys. Res., 2011, 116(A12):A12205 [8] MEREDITH N P, HORNE R B, THORNE R M, et al. Favored regions for chorus-driven electron acceleration to relativistic energies in the Earth's outer radiation belt[J]. Geophys. Res. Lett., 2003, 30(16):1871 [9] MEREDITH N P, HORNE R B, SICARD-PIET A, et al. Global model of lower band and upper band chorus from multiple satellite observations[J]. J. Geophys. Res., 2012, 117(A10):A10225 [10] NI Binbin, THORNE R M, SHPRITS Y Y, et al. Resonant scattering of plasma sheet electrons by whistler-mode chorus:contribution to diffuse auroral precipitation[J]. Geophys. Res. Lett., 2008, 35:L11106 [11] NI Binbin, THORNE R M, HORNE R B. Resonant scattering of plasma sheet electrons leading to diffuse auroral precipitation:1. evaluation for electrostatic electron cyclotron harmonic waves[J]. Geophys. Res. Lett., 2011, 116(A4):L11106 [12] NI Binbin, THORNE R M, MEREDITH N P, et al. Resonant scattering of plasma sheet electrons leading to diffuse auroral precipitation:2. evaluation for whistler mode chorus waves[J]. J. Geophys. Res., 2011, 116(A4):A04219 [13] THORNE R, NI BINBIN, TAO X, et al. Scattering by chorus waves as the dominant cause of diffuse auroral precipitation[J]. Nature, 2010, 467(7318):943-946 [14] MEREDITH N P, HORNE R B, GLAUERT S A, et al. Energetic outer zone electron loss timescales during low geomagnetic activity[J]. J. Geophys. Res., 2006, 111(A5):A05212 [15] SUMMERS D, MA C, MEREDITH N P, et al. Modeling outer-zone relativistic electron response to whistle-mode activity during substroms[J]. J. Atmos. Sol.:Terr. Phys., 2004, 66(2):133-146 [16] SUMMERS D. Quasi-linear diffusion coefficients for fieldaligned electromagnetic waves with applications to the magnetosphere[J]. J. Geophys. Res., 2005, 110(A8):A08213 [17] SUMMERS D, NI Binbin, MEREDITH N P. Timescales for radiation belt electron acceleration and loss due to resonant wave-particle interactions:1. theory[J]. J. Geophys. Res., 2007, 112(A4):A04206 [18] SUMMERS D, NI Binbin, MEREDITH N P. Timescales for radiation belt electron acceleration and loss due to resonant wave-particle interactions:2. evaluation for VLF chorus, ELF hiss, and electromagnetic ion cyclotron waves[J]. J. Geophys. Res., 2007, 112(A4):A04207 [19] MAUK B H, FOX N J, KANEKAL S G, et al. Science objectives and rationale for the radiation belt storm probes mission[J]. Space Sci. Rev., 2013, 179:3-27 [20] MOLDWIN M B, DOWNWARD L, RASSOUL H K, et al. A new model of the location of the plasmapause:CRRES results[J]. J. Geophys. Res., 2002, 107(A11):1339 [21] BORTNIK J, CUTLER J W, DUNSON C, et al. An automatic wave detection algorithm applied to Pc1 pulsations[J]. J. Geophys. Res., 2007, 112(A4):A04204 [22] TSURUTANI B T, VERKHOGLYADOVA O P, LAKHINA G S, et al. Properties of dayside outer zone chorus during HILDCAA events:loss of energetic electrons[J]. J. Geophys. Res., 2009, 114(A3):A03207
点击查看大图
计量
- 文章访问数: 838
- HTML全文浏览量: 66
- PDF下载量: 36
- 被引次数: 0