Physics of auroral phenomena : proceedings of the 40th annual seminar, Apatity, 13-17 March, 2017 / [ed. board: N. V. Semenova, A. G. Yahnin]. - Апатиты : Издательство Кольского научного центра РАН, 2017. - 143 с. : ил., табл.

Change in the spectralfeatures ofQP emissions due to poleward magnetic bay (f < 1.7 kHz) of emissions could be generated at higher L-shells by the trapped particles injected by the polar substorm in the magnetosphere. We note that the high-frequency QP emissions (“candles”) seemed to be rather similar to the QP event discussed by Titova et al. (2015) comparing the simultaneous observations on RBSP spacecraft above UK and the ground-based data at KAN and concluded that this QP event was generated inside of the plasmasphere. It can confirm our assumption of the mention above scenario of the wave generation. Wide frequency band observed in each individual QP element allows us to assume that the particles injected by polar substorm could scatter in different L-shells inside and outside of the plasmasphere and cause the cyclotron generation of waves simultaneously at different L-shells. a b с Figure 8. The wave paths of three VLF transmitters (a) crossing the polar substorm area, the changes in the amplitude (b) the scheme of an ionospheric disturbances influence on the wave propagation (c). Summary The ground-based observations o f QP emissions can be a very sensitive tool for studying the state of the magnetospheric maser [Trakhtengerts and Rycroft, 2008] controlled conditions of the VLF emission generation. It is shown that even a small substorm at the very high-latitudes located far away from the ground VLF receiver can break the self-oscillation regime of the cyclotron instability and change the dynamic spectra of QP emissions observed on the ground or provide the better conditions for wave to penetrate through the ionosphere. Acknew legm ents. This work was supported by the Program № 28 of the Presidium of the Russian Academy of Sciences and by the Academy o f Finland (grant no. 287988 for N.K. and L.G). References Manninen J., Kleimenova N.G., and Kozyreva O.V. (2012), New type of ensemble of quasi-periodic long-lasting VLF emissions at the auroral zone, Ann. Geophys. 30, 1655-1660. Manninen J., Demekhov A.G., Titova E.E., Kozlovsky A.E., and Pasmanik D.L. (2014), Quasi-periodic VLF emissions with short-period modulation and their relationship to whistlers: A case study, J. Geophys.Res. Space Physics, 119, 3544-3557. Titova E.E., Kozelov B.V., Demekhov A.G., Manninen J., Santolik O., Kletzing C.A., and Reeves G. (2015), Identification of the source of quasi-periodic VLF emissions using ground-based and Van Allen Probes satellite observations, Geophys. Res. Lett. 42, P. 6137-6145, doi:10.1002/2015GL064911. Trakhtengerts V.Y. and Rycroft MJ . Whistler and Alfven Mode Cyclotron Masers in Space (2008). Cambridge Univ. Press. Cambridge. U.K. 354 p. 53