Physics of auroral phenomena : proceedings of the 36th Annual seminar, Apatity, 26 February – 01 March, 2013 / [ed. board: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2013. - 215 с. : ил., табл.

our approximate calculations indicate on the fact that on 13 May 1987 the southern boundary of UREP did not become lower than 62° of North latitude for the radio-pass Ragby- Apatity. Southern boundary o f the ultra relativistic electron precipitation on May 13, 1987 Fig. 3 The discrepancy function GII(D) of parameter D. UT time UT time Fig. 4 Estimation of the accuracy of the inverse VLF problem of second kind by comparison of the experimental and calculated data. Black line - experimental data; red line - calculated data with optimal value of D = 1050 km. Conclusion The discrepancy function G11(D) gets its minimal value when (45 ± 5)% of the long radio pass is disturbed by the ultra-relativistic electron precipitation (on May 13, 1987). To this minimum a value ofNorth latitude, being equal to (62 ± 1)°, corresponds. R eferences 1. R em en ets, G. F., and М . I. B eloglazov, (1985) R eflection properties o f the low polar ionosphere, the peculiarities o f in to xicatio n and propagation o f the V L F w aves at high latitudes, Izvestija Vuzov. Radio Physics, 28, 1491-1504 (in Russian). 2. R em en ets, G. F. and М . I. B eloglazov, (1992) D ynam ics o f an auroral low ionospheric fringe at geophysical disturbances on 29 S ep tem b er 1989, P lanet S p a ce Sci., 40, 1101-1108. 3. R em en ets, G. F., (2001) Investigation o f the dynam ics o f high latitude upper atm osphere ionization due to the VLF ex p erim en tal data, Vestnick o f the St. P etersburg U niversity, series 4, issue 3, (no. 20), 2 3 -3 8 (in Russian). 4. B elog lazo v , М . I. and G. F. R em enets, (2005) Investigation o f pow erful VLF disturbances, Intern. J. Geom. A eronom .,} 5, No. 3, A pril issue, G I3004, doi: 10.10 2 9 /2 0 0 5G I0 0 0101. 5. B eloglazov, М . I. and G. F. R em enets, (2010) P henom enon o f ultra-relativistic electron precipitation in the m iddle polar atm osphere, in S cien ce C onference "The State an d P erspectives o f D evelopm ent o f the G eophysical Investigations at High L atitu d es", edited by V. G. V orobjov, (Polar G eophys. Inst, o f RA S, M urm ansk- A patity, Russia) 20-22 (in Russian). 6. B eloglazov, М . I. and G. F. R em enets, (2010) U ltra-relativistic electron precipitations as a m ain cause o f the m ost pow erful d isturbances in the m iddle po lar atm osphere, in P roceedings o f the 8th International C onference "Problems o f G eocosm os" h eld in St. P etersburg, R ussia, edited by V . S. Sem enov (S t Petersburg, 2010) 51-56. ISBN 978-5-9651-05045, h ttp ://g eo .p h y s.sp b u .ru/. 7. R em enets G. F., K ustov A. A. S outhern boundary o f the ultra-relativistic electron precipitation on M ay 13, 1987. In: 9th International conference “P rob lem s o f G eocosm os” . B ook o f abstracts. St. Petersburg, 2012. P. 222-224. 8. G un n in en E. М ., Z abavina I. N . P ropagation o f long radio w aves above the earth's surface. P roblem s o f the radio wave p ro p a g a tio n a n d diffraction. Issue 5. L eningrad, 1966. P. 5-30. 9. R em enets G. F. A bout the conditions o f quasi-degeneracy o f the norm al w aves in an anisotropic w aveguide. Problem s o f the radio w a v e p ro p a g a tio n an d diffraction. Issue 12. L eningrad, 1973. P. 195-207. 165