The paper reviews studies of the dynamics of relativistic electrons in the geosynchronous region. It lists the physical processes that lead to the acceleration of electrons filling the outer radiation belt. As one of the space weather factors, high-energy electron fluxes pose a serious threat to the operation of satellite equipment in one of the most populated orbital regions. Necessity is emphasized for efforts to develop methods of forecasting the situation in this part of the magnetosphere, possible predictors are listed, and their classification is given. An example of a predictive model for forecasting relativistic electron flux with a lead time of 1–2 days is proposed. Some questions of practical organization of prediction are discussed; the main objec-tives of short-term, medium-term, and long-term forecasts are listed.
radiation belts, relativistic electrons, forecast, magnetosphere, solar wind.
1. Baker D.N. The occurrence of operational anomalies in spacecraft and their relationship to space weather. IEEE Trans. Plasma Sci. 2000, vol. 28, pp. 2007-2016.
2. Baker D. Satellite anomalies due to space storms. Space Storms and Space Weather Hazards / Ed. Daglis I.A. New York, Springer Publ., 2001, chap. 10, pp. 251-284.
3. Baker D.N., Higbie P.R., Belian R.D., Hones E.W. Do Jovian electrons influence the terrestrial outer radiation zone? Ge-ophys. Res. Lett. 1979, vol. 6, pp. 531-534. DOI: 10.1029/ GL006i006p00531.
4. Baker D.N., Belian R.D., Higbie P.R., Klebesadel R.W., Blake J.B. Deep dielectric charging effects due to high energy electrons in the Earth's outer magnetosphere. J. Electrostatics. 1987, vol. 20, pp. 3-19.
5. Baker D.N., McPherron R.L., Cayton T.E., Klebesadel R.W. Linear prediction filter analysis of relativistic electron properties at 6.6 RE. J. Geophys. Res. 1990, vol. 95, no. A9, pp. 15133-15140. DOI:https://doi.org/10.1029/JA095iA09p15133.
6. Baker D.N., Allen J.H., Kanekal S.G., Reeves G.D. Disturbed space environment may have been related to Pager satellite failure. EOS Trans. AGU. 1998, p. 477.
7. Baker D.N., Kanekal S.G., Blake J.B., Pulkkinen T.I. The global efficiency of relativistic electron production in the Earth's magnetosphere. J. Geophys. Res. 2001, vol. 106, pp. 19169-19178.
8. Balikhin M.A., Boynton R.J., Walker S.N., Borovsky J.E., Billings S.A., Wei H.L. Using the NARMAX approach to model the evolution of energetic electrons fluxes at geostationary orbit. Geophys. Res. Lett. 2011, vol. 38, L18105. DOI: 10.1029/ 2011GL048980.
9. Borovsky J.E., Cayton T.E., Denton M.H., Belian R.D., Christensen R.A., Ingraham J.C. The proton and electron radia-tion belts at geosynchronous orbit: Statistics and behavior during high-speed stream-driven storms. J. Geophys. Res.: Space Phys. 2016, vol. 121, pp. 5449-5488. DOI: 10.1002/ 2016JA022520.
10. Brautigam D.H., Albert J.M. Radial diffusion analysis of outer radiation belt electrons during the October 9, 1990 mag-netic storm. J. Geophys. Res. 2000, vol. 105, pp. 291-309. DOI:https://doi.org/10.1029/1999JA900344.
11. Degtyarev V.I., Chudnenko S.E., Kharchenko I.P., Tsegmed B., Xue B. Prediction of maximal daily average values of relativistic electron fluxes in geostationary orbit during the magnetic storm recovery phase. Geomagnetism and Aero-nomy. 2009a, vol. 49, no. 8, pp. 1208-1217. DOI: 10.1134/ S0016793209080349.
12. Degtyarev V.I., Kharchenko I.P., Potapov A.S., Tsegmed B., Chudnenko S.E. Qualitative estimation of magnetic storm efficiency in producing relativistic electron flux in the Earth's outer radiation belt using geomagnetic pulsations data. Adv. Space Res. 2009b, vol. 43, pp. 829-836. DOI:https://doi.org/10.1016/j.asr. 2008.07.004.
13. Degtyarev V.I., Kharchenko I.P., Potapov A.S., Tsegmed B., Chudnenko S. E. The relation between geomagnetic pulsations and an increase in the fluxes of geosynchronous relativistic electrons during geomagnetic storms. Geomagnetism and Aeronomy. 2010, vol. 50, no. 7, pp. 885-893. DOI: 10.1134/ S0016793210070108.
14. Efitorov A., Myagkova I., Sentemova N., et al. Prediction of relativistic electrons flux in the outer radiation belt of the Earth using adaptive methods. Biologically Inspired Cognitive Architectures (BICA) for Young Scientists. Springer Inter-national Publ., 2016. P. 281-287. (Adv. Intelligent Systems and Computing. vol. 449). URL: http://link.springer.com/chapter/ 10.1007%2F978-3-319-32554-5_36#page-1 (accessed September 30, 2016).
15. Elkington S.R., Hudson M.K., Chan A.A. Acceleration of relativistic electrons via drift-resonant interaction with toroidal-mode Pc-5 ULF oscillations. Geophys. Res. Lett. 1999, vol. 26, no. 21, pp. 3273-3276.
16. Fujimoto M., Nishida A. Energization and anisotropization of energetic electrons in the Earth's radiation belt by the recirculation process. J. Geophys. Res. 1990, vol. 95, no. A4, pp. 4265-4270. DOI:https://doi.org/10.1029/JA095iA04p04265.
17. Freeman J.W., O'Brien T.P., Chan A.A., Wolf R.A. Energetic electrons at geostationary orbit during the November 3-4, 1993 storm: Spatial/temporal morphology, characterization by a power law spectrum and, representation by an artificial neural network. J. Geophys. Res. 1998, vol. 103, pp. 26251-26260. DOI:https://doi.org/10.1029/97JA03268.
18. Friedel R.H.W., Reeves G.D., Obara T. Relativistic electron dynamics in the inner magnetosphere - A review. J. Atmos. Solar-Terr. Phys. 2002, vol. 64, pp. 265-282.
19. Gal’per A.M., Grachev V.M., Dmitrenko V.V., Kirillov-Ugryumov V.G., Ulin S.E. New component of the Earth's inner radiation belt: High-energy electrons. JETP Lett. 1983, vol. 38, no. 8, pp. 497-500.
20. Green J.C., Kivelson M.G. Relativistic electrons in the outer radiation belt: Differentiating between acceleration mechanisms. J. Geophys. Res. 2004, vol. 109, A03213. DOI: 10.1029/ 2003JA010153.
21. Gubar 'Yu.I. Drift resonance of relativistic electrons with ULF waves as a nonlinear resonance. Cosmic Res. 2010, vol. 48, no. 4, pp. 300-307. DOI:https://doi.org/10.1134/S0010952510040039.
22. Horne R.B., Thorne R.M. Potential waves for relativistic electron scattering and stochastic acceleration during magnetic storms. Geophys. Res. Lett. 1998, vol. 25, pp. 3011-3014. DOI:https://doi.org/10.1029/98GL01002.
23. Hudson M.K., Elkington S.R., Lyon J.G., Goodrich C.C. Increase in relativistic electron flux in the inner magnetosphere: ULF wave mode structure. Adv. Space Res. 2000, vol. 25, no. 12, pp. 2327-2337. DOI:https://doi.org/10.1016/S0273-1177(99)00518-9.
24. Kellerman A.C., Shprits Y.Y. On the influence of solar wind conditions on the outer-electron radiation belt. J. Geophys. Res. 2012, vol. 117, A05217. DOI:https://doi.org/10.1029/2011JA017253.
25. Kessel M. Things we do not yet understand about solar driving of the radiation belts. J. Geophys. Res.: Space Phys. 2016, vol. 121, pp. 5549-5552. DOI:https://doi.org/10.1002/2016JA022472.
26. Kuznetsov S.N. Izbrannye trudy po solnechno-zemnoi fizike [Selected Works on Solar-Terrestrial Phys.]. Moscow, Universitetskaya Kniga Publ., 2010, 256 p. (In Russian).
27. Li X., Temerin M., Baker D.N., Reeves G.D., Larson D. Quantitative prediction of radiation belt electrons at geosta-tionary orbit based on solar wind measurements. Geophys. Res. Lett. 2001, vol. 28, pp. 1887-1890. DOI:https://doi.org/10.1029/2000GL012681.
28. Li L., Cao J., Zhou G. Combined acceleration of electrons by whistler-mode and compressional ULF turbulences near the geosynchronous orbit. J. Geophys. Res. 2005, vol. 110, A03203. DOI:https://doi.org/10.1029/2004JA010628.
29. Li L.Y., Cao J.B., Zhou G.C., Li X. Statistical roles of storms and substorms in changing the entire outer zone relativistic electron population. J. Geophys. Res. 2009, vol. 114, A12214. DOI:https://doi.org/10.1029/2009JA014333.
30. Ling A.G., Ginet G.P., Hilmer R.V., Perry K.L. A neural network-based geosynchronous relativistic electron flux forecasting model. Space Weather. 2010, vol. 8, S09003. DOI:https://doi.org/10.1029/2010SW000576.
31. Lyatsky W., Khazanov G.V. Effect of geomagnetic disturbances and solar wind density on relativistic electrons at geo-stationary orbit. J. Geophys. Res. 2008, vol. 113, A08224. DOI:https://doi.org/10.1029/2008JA013048.
32. Lyons L.R., Lee D.-Y., Thorne R.M., Horne R.B., Smith A.J. Solar wind-magnetosphere coupling leading to relativistic electron energization during high-speed streams. J. Geophys. Res. 2005, vol. 110, A11202. DOI:https://doi.org/10.1029/2005JA011254.
33. Mann I.R., O’Brien T.P., Milling D.K. Correlations between ULF wave power, solar wind speed, and relativistic electron flux in the magnetosphere: Solar cycle dependence. J. Atmos. Solar-Terr. Phys. 2004, vol. 66, pp. 187-198.
34. Mathie R.A., Mann I.R. On the solar wind control of Pc5 ULF pulsation power at midlatitudes: Implications for MeV electron acceleration in the outer radiation belt. J. Geophys. Res. 2001, vol. 106, pp. 29783-29796.
35. Miyoshi Y., Kataoka R. Ring current ions and radiation belt electrons during geomagnetic storms driven by coronal mass ejections and corotating interaction regions. Geophys. Res.Lett. 2005, vol. 32, L21105. DOI:https://doi.org/10.1029/2005GL024590.
36. Miyoshi Y., Kataoka R. Flux enhancement of the outer radiation belt electrons after the arrival of stream interaction regions. J. Geophys. Res. 2008, vol. 113, A03S09. DOI:https://doi.org/10.1029/2007 JA012506.
37. Myagkova I.N., Dolenko S.A. Comparative analysis of the quality of prediction for fluences of relativistic electrons of the outer radiation belt of the Earth at different phases of the solar activity cycle. 11th International Conference and School “Problems of Geocosmos”: Book of Abstracts. St.-Petersburg, October 3-7, 2016. St.-Petersburg, 2016, p. 79.
38. Nagai T. Space weather forecast: Prediction of relativistic electron intensity at synchronous orbit. Geophys. Res. Lett. 1988, vol. 15, pp. 425-428.
39. O’Brien T.P., Lorentzen K.R., Mann I.R., Meredith N.P., Blake J.B., Fennell J.F., Looper M.D., Milling D.K., Anderson R.R. Energization of relativistic electrons in the presence of ULF power and MeV microbursts: Evidence for dual ULF and VLF acceleration. J. Geophys. Res. 2003, vol. 108, no. A8, pp. 2156-2202. DOI:https://doi.org/10.1029/2002JA009784.
40. Ozeke L.G., Mann I.R., Murphy K.R., Rae I.J., Milling D.K. Analytic expressions for ULF wave radiation belt radial diffusion coefficients. J. Geophys. Res.: Space Physics. 2014, vol. 119, pp. 1587-1605. DOI:https://doi.org/10.1002/2013JA019204.
41. Parker E.N. Geomagnetic fluctuations and the form of the outer zone of the Van Allen radiation belt. J. Geophys. Res. 1960, vol. 65, no. 10, pp. 3117-3130. DOI: 10.1029/ JZ065i010p03117.
42. Paulikas G.A., Blake J.B. Effects of the solar wind on magnetospheric dynamics: Energetic electrons at the synchronous orbit. Quantitative Modeling of Magnetospheric Processes. 1979. pp. 180-202. (Geophys. Monogr. Amer. Geophys. Un., Vol. 21).
43. Perry K.L., Ginet G.P., Ling A.G., Hilmer R.V. Comparing geosynchronous relativistic electron prediction models. Space Weather. 2010, vol. 8, S12002. DOI: 10.1029/ 2010SW000581.
44. Pilipenko V.A., Romanova N.V. The impact of space weather on the operation of spacecraft. Geofizicheskie issledovaniya [Geophys. Res.]. 2005, no. 2, pp. 71-82. (In Russian).
45. Pilipenko V., Yagova N., Romanova N., Allen J. Statistical relationships between the satellite anomalies at geostationary orbits and high-energy particles. Adv. Space Res. 2006, vol. 37, no. 6, pp. 1192-1205.
46. Potapov A.S. ULF wave activity in high-speed streams of the solar wind: Impact on the magnetosphere. J. Geophys. Res.: Space Phys. 2013, vol.118, no. 10, pp. 6465-6477. DOI:https://doi.org/10.1002/2013JA019119.
47. Potapov A.S., Tsegmed B., Ryzhakova L.V. Relationship between the fluxes of relativistic electrons at geosynchronous orbit and the level of ULF activity on the Earth's surface and in the solar wind during the 23rd solar activity cycle. Cosmic Res. 2012, vol. 50, no. 2, pp. 124-140. DOI: 10.1134/ S0010952512020086.
48. Potapov A.S., Tsegmed B., Ryzhakova L.V. Solar cycle variation of "killer" electrons at geosynchronous orbit and electron flux correlation with the solar wind parameters and ULF waves intensity. Acta Astronautica. 2014, vol. 93, pp. 55-63. DOI:https://doi.org/10.1016/j.actaastro.2013.07.004.
49. Potapov A.S., Ryzhakova L.V., Tsegmed B. A new approach to predict and estimate enhancements of "killer" electron flux at geosynchronous orbit. Acta Astronautica. 2016, vol. 126, pp. 47-51. DOI:https://doi.org/10.1016/j.actaastro.2016.04.017.
50. Potapov A.S., Ryzhakova L.V., Tsegmed B. A method to forecast the relativistic electron flux at geostationary orbit. Vestnik SibGAU [Bull. of Siberian State Aerospace University]. 2016, vol. 17, no. 3, pp. 611-617. (In Russian).
51. Reeves G.D., McAdams K.L., Friedel R.H.W., O’Brien T.R. Acceleration and loss of relativistic electrons during geomagnetic storms. Geophys. Res. Lett. 2003, vol. 30, no. 10, 1529. DOI:https://doi.org/10.1029/2002GL016513.
52. Reeves G.D., Morley S.K., Friedel R.H.W., Henderson M.G., Cayton T.E., Cunningham G., Blake J.B., Christensen R.A., Thomsen D. On the relationship between relativistic electron flux and solar wind velocity: Paulikas and Blake revisited. J. Geophys. Res. 2011, vol. 116, A02213. DOI: 10.1029/ 2010JA015735.
53. Reeves G., Morley S., Cunningham G. Long-term variations in solar wind velocity and radiation belt electrons. J. Ge-ophys. Res.: Space Physics 2013, vol. 118, no. 3, pp. 1040-1048. DOI:https://doi.org/10.1002/jgra.50126.
54. Roeder J.L., Fennell J.F., O'Brien T.P. Acceleration and losses of relativistic electrons due to whistler-mode chorus: SCATHA observations. AGU Fall Meeting. 2005, Abstract # SM41D-07.
55. Romanova N., Pilipenko V. ULF wave indices to characterize the solar wind - magnetosphere interaction and relativistic electron dynamics. Acta Geophys. 2009, vol. 57, pp. 158-170. DOI:https://doi.org/10.2478/s11600-008-0064-4.
56. Romanova N.V., Pilipenko V.A., Yagova N.V., Belov A.V. Statistical correlation of the rate of failures on geosynchronous satellites with fluxes of energetic electrons and protons. Cosmic Res. 2005, vol. 43, no. 3, pp. 179-185. DOI:https://doi.org/10.1007/s10604-005-0032-6.
57. Romanova N., Pilipenko V., Crosby N., Khabarova O. ULF wave index and its possible applications in space physics. Bulg. J. Phys. 2007, vol. 34, pp. 136-148.
58. Romanova N.V., Chizhenkov V.A., Pilipenko V.A. Possible relation of emergencies during spacecraft launches from the Plesetsk site to high-latitude geomagnetic disturbances. Geomagn. Aeron. 2009, vol. 49, no. 1, pp. 104-109. DOI:https://doi.org/10.1134/S0016793209010149.
59. Sakaguchi K., Nagatsuma T., Reeves G.D., Spence H.E. Prediction of MeV electron fluxes throughout the outer radiation belt using multivariate autoregressive models. Space Weather. 2015, vol. 13, pp. 853-867. DOI: 10.1002/ 2015SW001254.
60. Schulz M., Lanzerotti L. Particle Diffusion In The Radiation Belts. Berlin, Springer Pabl., 1974, 218 p.
61. Sheldon R.B., Spence H.E., Sullivan J.D., Fritz T.A., Chen J. The discovery of trapped energetic electrons in the outer cusp. Geophys. Res. Lett. 1998, vol. 25, no. 11, pp. 1825-1828.
62. Shiroky V.R., Dolenko S.A., Myagkova I.N., Sentemova N.S. A study of neural network forecasting horizon of the Earth’s magnetosphere state, XVIIIth International Scientific and Technical Conference “Neuroinformatika-2016”, Collection of scientific papers. In 3 parts. Moscow, NIYU MIPhI Pabl., 2016, Pt. 1, pp. 172-182. (In Russian).
63. Shprits Y., Drozdov A.Y., Spasojevic M., Kellerman A.C., Usanova M.E., Engebretson M.J., Agapitov O.V., Orlova K.G., Zhelavskaya I.S., Raita T., Spence H.E., Baker D.N., Zhu H. Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts. Nature Communications. 2016, vol. 7, 12883. DOI: 10.1038/ ncomms12883.
64. Simms L.E., Pilipenko V., Engebretson M.J., Reeves G.D., Smith A.J., Clilverd M. Prediction of relativistic electron flux at geostationary orbit following storms: Multiple regression analysis. J. Geophys. Res.: Space Phys. 2014, vol. 119, no. 9, pp. 7297-7318. DOI:https://doi.org/10.1002/2014JA019955.
65. Simms L.E., Engebretson M.J., Smith A.J., Clilverd M., Pilipenko V., Reeves G.D. Analysis of the effectiveness of ground-based VLF wave observations for predicting or nowcasting relativistic electron flux at geostationary orbit. J. Geophys. Res.: Space Phys. 2015, vol. 120, pp. 2052-2060. DOI: 10.1002/ 2014JA020337.
66. Simms L.E., Engebretson M.J., Pilipenko V., Reeves G.D., Clilverd M. Empirical predictive models of daily relativistic electron flux at geostationary orbit: Multiple regression analysis. J. Geophys. Res.: Space Phys. 2016, vol. 121, pp. 3181-3197. DOI:https://doi.org/10.1002/2016JA022414.
67. Summers D., Ma C. A model for generating relativistic electrons in the Earth's inner magnetosphere based on gyroresonant wave-particle interactions. J. Geophys. Res. 2000, vol. 105, no. A2, pp. 2625-2640. DOI: 10.1029/ 1999JA900444.
68. Summers D., Ni B., 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. Geophys. Res. 2007, vol. 112, A04207. DOI:https://doi.org/10.1029/2006JA011993.
69. Temny V.V. History of the discovery of the Earth's radiation belts: Who, when and how? Zemlya i Vselennaya [Earth and Universe]. 1993, no. 5, pp. 69-76. (In Russian).
70. Turner D.L., Morley S.K., Miyoshi Y., et al. Outer radiation belt flux dropouts: Current understanding and unresolved questions. Dynamics of Earth’s Radiation Belts and Inner Magnetosphere. Ed. by D. Summers et al. 2012, рр. 195-212. (Geophys. Monogr. Ser., Vol. 199). DOI:https://doi.org/10.1029/2012GM001310.
71. Tverskoy B.A. Capture of fast particles from interplanetary space. Izv. AN SSSR. Ser. fiz. [Bull. Russian Academy of Sciences. Physics]. 1964, vol. 28, pp. 2099-2103. (In Russian).
72. Tverskoy B.A. Dinamika radiatsionnykh poyasov Zemli [Dynamics of the Earth’s radiation belts]. Moscow, Nauka Publ., 1968. 224 p. (In Russian).
73. Ukhorskiy A.Y., Sitnov M.I., Sharma A.S., Anderson B.J., Ohtani S., Lui A.T.Y. Data-derived forecasting model for relativistic electron intensity at geosynchronous orbit. Geophys. Res. Lett. 2004, vol. 31, L09806. DOI:https://doi.org/10.1029/2004GL019616.
74. Ukhorskiy A.Y., Sitnov M.I., Millan R.M., Kress B.T., Smith D.C. Enhanced radial transport and energization of radia-tion belt electrons due to drift orbit bifurcations. J. Geophys. Res.: Space Physics. 2014. vol. 119, pp. 163-170. DOI: 10.1002/ 2013JA019315.
75. Ukhorskiy A. Y., Sitnov M.I., Millan R.M., Kress B.T., Fennell J.F., Claudepierre S.G., Barnes R.J. Global storm time depletion of the outer electron belt. J. Geophys. Res.: Space Phys. 2015, vol. 120, pp. 2543-2556. DOI:https://doi.org/10.1002/2014JA020645.
76. Weigel R.S., Klimas A.J., Vassiliadis D. Precursor analysis and prediction of large-amplitude relativistic electron fluxes. Space Weather. 2003, vol. 1, p. 1014. DOI: 10.1029/ 2003SW000023.
77. Xiao F., Shen C., Wang Y., Zheng H., Wang S. Energetic electron distributions fitted with a relativistic kappa-type function at geosynchronous orbit. J. Geophys. Res. 2008, vol. 113, A05203. DOI:https://doi.org/10.1029/2007JA012903.
78. URL: https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQRReeeIY4NuZm-hTm8qUT6aNUkZ53jtpe Cd8eo6d-pL88X2DVNZw/ (accessed September 30, 2016).
79. URL: http://www.swpc.noaa.gov/products/relativistic-elect-ron-forecast-model/ (accessed September 30, 2016).
80. URL: http://ulf.gcras.ru/ (accessed September 30, 2016).
