Physics of auroral phenomena : proceedings of the 33rd Annual seminar, Apatity, 02 - 05 March, 2010 / [ed.: A.G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2011. - 206 с. : ил.

А. V. Artemyev al al. Conclusions In this work the model of turbulent electromagnetic field with intermittency has been developed. It has been shown that the degree o f intermittency can be varied and set as a free parameter o f the model. Moreover the possibility of our model to approximate qualitatively the experimental observation has been demonstrated. Numerical calculations show that more efficient particle acceleration occurs in a more intermittent field. The effect of the influence of intermittency on the ratio between spatial transport and particle acceleration has been briefly discussed: in the intermittent field energy gained by particle turns out to be larger than in the non-intermittent field. The obtained results can explain the particle acceleration up to high energies even in the rather localized regions of the electromagnetic field of the turbulent Earth's magnetotail while the level of spatial transport remain the same. A cknow ledgm en ts. This work was supported in part by the RF Presidential Program for State Support o f Leading Scientific Schools (project no. NSh-320.2010.2), the Russian Foundation for Basic Research (projects n. 10-02- 00135), State Contract n. 02.740.11.5064. References Christon, S. P., D. J. Williams, D. G. Mitchell, L. A. Frank, and C. Y. Huang, Spectral characteristics of plasma sheet ion and electron populations during undisturbed geomagnetic conditions, J. Geophys. Res., 94, 13,409-13,424, doi: 10.1029/JA094iAl Op13409 Drake, J. F., M. Swisdak, H. Che, and M. A. Shay, Electron acceleration from contracting magnetic islands during reconnection, Nature, 443, 553-556, doi:10.1038/nature05116, 2006. Dudok de Wit, Т., and V. V. Krasnosel'skikh, Nongaussian statistics in space plasma turbulence: fractal properties and pitfalls, Nonlinear Processes in Geophysics, 3, 262-273, 1996. Frisch, U., Turbulence. The legacy o fA. N. Kolmogorov., 1995. Hoshino, М., Electron surfing acceleration in magnetic reconnection, J. Geophys. Res., 110, 10,215, doi: 10.1029/2005JA011229,2005. Lyons, L. R. and Speiser, T. W. Evidence for current sheet acceleration in the geomagnetic tail. J. Geophys. Res., 87, 2276-2286,1982 Manneville, P., Intermittency, self-similarity and 1/f spectrum in dissipative dynamical systems, J. Physique, 41, 1235-1243, 1980. Ono, Y., M. Nose, S. P. Christon, and A. T. Y. Lui, The role o f magnetic field fluctuations in nonadiabatic acceleration of ions during dipolarization, J. Geophys. Res., 114, 5209, doi:10.1029/2008JA013918,2009. Perri, S., A. Greco, and G. Zimbardo, Stochastic and direct acceleration mechanisms in the earth's magnetotail, Geophys. Res. Lett., 3 6 , 4103, doi:10.1029/2008GL036619,2009. Petrukovich, A. A., Low frequency magnetic fluctuations in the earth's plasma sheet, in Astrophysics and Space Science Library, Astrophysics and Space Science Library, vol. 321, edited by A. S. Sharma and P. K. Kaw, pp. 145, 2005. Sarris, E. Т., S. M. Krimigis, and T. P. Armstrong, Observations o f magnetospheric bursts o f high-energy protons and electrons at approximately 35 earth radii with imp 7, J. Geophys. Res., 81, 2341-2355, doi: 10.1029/JA081Ю13p02341, 1976. Vasyliunas, V. М., A survey of low-energy electrons in the evening sector of the magnetosphere with ogo 1 and ogo 3, J. Geophys. Res., 73, 2839, doi: 10.1029/JA073i009p02839, 1968. Veltri, P., G. Zimbardo, A. L. Taktakishvili, and L. M. Zelenyi, Effect of magnetic turbulence on the ion dynamics in the distant magnetotail, J. Geophys. Res., 103, 14,897-14,916, doi:10.1029/98JA00211, 1998. Voros, Z., W. Baumjohann, R. Nakamura, A. Runov, M. Volwerk, T. L. Zhang, and A. Balogh, Wavelet analysis of magnetic turbulence in the earth's plasma sheet, Physics o fPlasmas, 11, 1333-1338, doi: 10.1063/1.1667499, 2004. Zelenyi, L., A. Artemyev, H. Malova, A. V. Milovanov, and G. Zimbardo, Particle transport and acceleration in a time-varying electromagnetic field with a multi-scale structure, Physics Letters A, 372, 6284-6287, doi: 10.1016/j.physleta.2008.08.035, 2008. 1 2