Journal of Astronomy and Space Sciences

The Korean Space Science Society (한국우주과학회)
권호 표지
DOI QR코드

DOI QR Code

Dependence of Energetic Electron Precipitation on the Geomagnetic Index Kp and Electron Energy

  • Park, Mi-Young (Department of Astronomy and Space Science Chungbuk National University) ;
  • Lee, Dae-Young (Department of Astronomy and Space Science Chungbuk National University) ;
  • Shin, Dae-Kyu (Department of Astronomy and Space Science Chungbuk National University) ;
  • Cho, Jung-Hee (Department of Astronomy and Space Science Chungbuk National University) ;
  • Lee, Eun-Hee (Yonsei University Observatory)
  • Received : 2013.11.04
  • Accepted : 2013.11.17
  • Published : 2013.12.15
Download PDF
⟨ Previous Next ⟩

Abstract

It has long been known that the magnetospheric particles can precipitate into the atmosphere of the Earth. In this paper we examine such precipitation of energetic electrons using the data obtained from low-altitude polar orbiting satellite observations. We analyze the precipitating electron flux data for many periods selected from a total of 84 storm events identified for 2001-2012. The analysis includes the dependence of precipitation on the Kp index and the electron energy, for which we use three energies E1 > 30 keV, E2 > 100 keV, E3 > 300 keV. We find that the precipitation is best correlated with Kp after a time delay of < 3 hours. Most importantly, the correlation with Kp is notably tighter for lower energy than for higher energy in the sense that the lower energy precipitation flux increases more rapidly with Kp than does the higher energy precipitation flux. Based on this we suggest that the Kp index reflects excitation of a wave that is responsible for scattering of preferably lower energy electrons. The role of waves of other types should become increasingly important for higher energy, for which we suggest to rely on other indicators than Kp if one can identify such an indicator.

Keywords

References

  1. Angelopoulos V, The THEMIS mission, SSRv, 141, 5-34 (2008). http://dx.doi.org/10.1007/s11214-008-9336-1
  2. Bortnik JR, Thorne M, O'Brien TP, Green JC, Strangeway RJ, et al., Observation of two distinct, rapid loss mechanisms during the 20 November 2003 radiation belt dropout event, JGR, 111, A12216 (2006). http:// dx.doi.org/10.1029/2006JA011802
  3. Green JC, Kivelson MG, Relativistic electrons in the outer radiation belt: Differentiating between acceleration mechanisms, JGR, 109, A03213 (2004). http://dx.doi. org/10.1029/2003JA010153
  4. Green JC, Onsager TG, O'Brien TP, Baker DN, Testing loss mechanisms capable of rapidly depleting relativistic electron flux in the Earth's outer radiation belt, JGR, 109, A12211, (2004). http://dx.doi. org/10.1029/2004JA010579
  5. Horne RB, Thorne RM, Relativistic electron acceleration and precipitation during resonant interactions with whistler-mode chorus, GRL, 30(10), 1527 (2003). http:// dx.doi.org/10.1029/2003GL016973
  6. Hwang J, Lee DY, Kim KC, Shin DK, Kim JH, et al., Significant loss of energetic electrons at the heart of the outer radiation belt during weak magnetic storms, JGR, 118, 4221-4236 (2013). http://dx.doi.org/10.1002/jgra.50410
  7. Kim HJ, Chan AA, Fully adiabatic changes in storm time relativistic electron fluxes, JGR, 102(10), 22107-22116 (1997). https://doi.org/10.1029/97JA01814
  8. Kim KC, Lee DY, Kim HJ, Lee ES, Choi CR, Numerical estimates of drift loss and Dst effect for outer radiation belt relativistic electrons with arbitrary pitch angle, JGR, 115, A03208 (2010). http://dx.doi. org/10.1029/2009JA014523
  9. Kim KC, Lee DY, Kim HJ, Lyons LR, Lee ES, et al., Numerical calculations of relativistic electron drift loss effect, JGR, 113, A09212, (2008). http://dx.doi. org/10.1029/2007JA013011
  10. Kim KC, Shprits Y, Subbotin D, Ni B, Understanding the dynamic evolution of the relativistic electron slot region including radial and pitch angle diffusion, JGR, 116, A10214 (2011). http://dx.doi. org/10.1029/2011JA016684
  11. Lam MM, Horne RB, Meredith NP, Glauert SA, Moffat- Griffin T, et al., Origin of energetic electron precipitation > 30 keV into the atmosphere, JGR 115, A00F08 (2010). http://dx.doi.org/10.1029/2009JA014619
  12. Lee DY, Shin DK, Kim JH, Cho JH, Kim KC, et al., Longterm loss and re-formation of the outer radiation belt, JGR, 118, 3297-3313 (2013). http://dx.doi.org/10.1002/ jgra.50357
  13. Lee JH, Lee DY, Park MY, Kim KC, Kim HS, Magnetic turbulence associated with magnetic dipolarizations in the near-tail of the Earth's magnetosphere: Test of anisotropy, JASS, 28, 117-122 (2011). http://dx.doi. org/10.5140/JASS.2013.30.2.095
  14. Li W, Thorne RM, Nishimura Y, Bortnik J, Angelopoulos V, et al. THEMIS analysis of observed equatorial electron distributions responsible for the chorus excitation, JGR, 115, A00F11 (2010). http://dx.doi. org/10.1002/2009JA014845
  15. Lyons LR, Lee DY, Thorne RM, Horne RB, Smith AJ, Solar wind-magnetosphere coupling leading to relativistic electron energization during high-speed streams JGR, 110, A11202 (2005). http://dx.doi. org/10.1029/2005JA011254
  16. Millan RM, Thorne RM, Review of radiation belt relativistic electron losses, J. Atmos. Solar Terr. Phys., 69, 362-377 (2007). http://dx.doi.org/10.1016/j.jastp.2006.06.019
  17. Millan RM, Lin RP, Smith DM, McCarthy MP, Observation of relativistic electron precipitation during a rapid decrease of trapped relativistic electron flux, GRL, 34, L10101 (2007). http://dx.doi.org/10.1029/2006GL028653
  18. Ohtani S, Miyoshi Y, Singer HJ, Weygand JM, On the Loss of Relativistic Electrons at Geosynchronous Altitude: Its Dependence on Magnetic Configurations and External Conditions, JGR, 114, A01202 (2009). http://dx.doi. org/10.1029/2008JA013391
  19. Rodger CJ, Clilverd MA, Green JC, Lam MM, Use of POES SEM-2 observations to examine radiation bet dynamics and energetic electron precipitation into the atmosphere, JGR, 115, A04202 (2010). http://dx.doi. org/10.1029/2008JA014023
  20. Shprits YY, Subbotin DA, Meredith NP, Elkington SR, Review of modeling of losses and sources of relativistic electrons in the outer radiat ion bel t II : Local acceleration and loss, JASTP, 70, 1694-1713 (2008). http://dx.doi.org/10.1016/j.jastp.2008.06.014
  21. Shprits YY, Subbotin DA, Ni B, Evolution of electron fluxes in the outer radiation belt computed with the VERB code, JGR,114, A11209 (2009). http://dx.doi. org/10.1029/2008JA013784
  22. Summers D, Ni B, Meredith NP, Timescales for radiation belt electron acceleration and loss due to resonant waveparticle interactions: 2. Evaluation for VLF chorus, ELF hiss, and electromagnetic ion cyclotron waves, JGR, 112, A04207 (2007). http://dx.doi.org/10.1029/2006JA011993
  23. Turner DL, Shprits Y, Hartinger M, Angelopoulos V, Explaining sudden losses of outer radiation belt electrons during geomagnetic storms, Nature-Phys, 8, 208-212 (2012). http://dx.doi.org/10.1038/NPHYS2185
  24. Ukhorskiy AY, Anderson BJ, Brandt PC, Tsyganenko NA, Storm time evolution of the outer radiation Belt : Transport and losses, JGR, 111, A11S03 (2006). http:// dx.doi.org/10.1029/2006JA011690

Cited by

  1. Model CRAC:EPII for atmospheric ionization due to precipitating electrons: Yield function and applications vol.121, pp.2, 2016, https://doi.org/10.1002/2015JA022276
  2. Pitch-angle diffusion of electrons through growing and propagating along a magnetic field electromagnetic wave in Earth's radiation belts vol.22, pp.6, 2015, https://doi.org/10.1063/1.4923267
  3. Estimation of pitch angle diffusion rates and precipitation time scales of electrons due to EMIC waves in a realistic field model vol.120, pp.10, 2015, https://doi.org/10.1002/2014JA020644
  4. Atmospheric ionization induced by precipitating electrons: Comparison of CRAC:EPII model with a parametrization model vol.149, 2016, https://doi.org/10.1016/j.jastp.2016.04.020