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.

“P hysics o f Auroral P henom ena”, Proc. XXXIII A n nua l Sem inar, A patity, pp. 99 -1 0 2 , 2011 © Kola Science Centre, Russian Academy of Science, 2011 Polar Geophysical Institute EARLY FORECAST OF RADIATION HAZARDOUS SOLAR COSMIC RAY FLUXES ON THE NEUTRON MONITORS DATA E.V. Vashenyuk, Yu.V. Balabin, B.B. Gvozdevsky, A.V. Germanenko (Polar Geophysical Institute KSC RAS, 15, Khalturina Str., Murmansk, 183010, Russia; E-mail: vashenyuk@pgia.ru) . Abstract. Possibility of the forecast of radiation-hazardous solar cosmic ray fluxes with energies in tens-hundreds MeV according to the neutron monitors located on a ground surface is discussed. Neutron monitors register the relativistic SCR (energies from 0.5 to a several GeV) with the minimal delay, however in a high-energy region intensity SCR is small and does not represent serious radiation hazard. At the same time, having spotted a spectrum a SCR in a high-energy region it is possible to give the forecast of radiation-hazardous fluxes of particles of moderate energies with advance time till several hours. However this forecast is possible only by data from so-called «delayed component» o f relativistic cosmic rays. 1. Introduction It is known that the maximum flux of cosmic rays in the radiation-dangerous energies of tens to hundreds of MeV are registered with a delay from ~ 1 to 1 0 hours in comparison with relativistic cosmic rays, which cause the increases in neutron monitors (NM). This enables real-time forecasting of radiation hazard SCR according to neutron monitors. In a number of authors in recent years the procedure of definition o f parameters of the relativistic SCR according to a land network of neutron monitors (NM) has been developed [1,2]. The method uses the inverse problem for resolve minorities’ characteristics of relativistic solar protons outside the atmosphere and Earth's magnetosphere from the NM network data. In the method [1 ,2 ] the calculated with great precision in modem models of the magnetosphere asymptotic cones of reception stations NM are also used. It has been shown, that in the flux of relativistic solar protons (RSP) are observed two components: the prompt component (PC) and the delayed component (DC) with specific properties [3, 4]. In the methods of forecasting can be used, that for the delayed component of CPR, the energy spectra in good agreement with direct measurements o f solar protons of lower energies during the peak, sometimes coming within a few hours [2, 3]. Thus, identifying the spectrum of DC in the energy region with the lower limit of ~ 430 MeV (an atmospheric energy threshold for neutron monitors) can, by means o f its extrapolation in the energy range of the hundreds and tens of MeV, to estimate fluxes of these particles in the absence o f direct measurements, as well as give the forecast o f these fluxes in the next hours. The problems here are limited number of available data from the NM stations and deficit of time for data processing and calculations. The usual procedure of such calculations require data no less than 30-35 NM stations, detailed calculations of the asymptotic cones of accept in the modem models of the magnetosphere [1,2]. With the advent of a network of the NM stations (23), giving the real-time data into a single database (European Project NMDB) [5] the possibility o f implementing such a forecast was created. We have developed a reasonably restricted computational model using data of about 20 stations NM. It performs calculations o f asymptotic cones in the model Tsyganenko 1989 and allows obtaining the spectra of relativistic solar protons (RSP) in real time with a sufficient degree of accuracy. Testing of a restricted method by comparing the data obtained with the help of the parameters of CPR with the results of the full method [1,2] has shown the good agreement between the two. Thus, we can expect that the proposed here method of estimating the radiation hazards related with the SCR, based on data of neutron monitors, will be developed and will be used in the upcoming cycle of solar activity. In following section in a number of examples method possibilities are shown. 1. Analysis of separate events 1.1. Event of 21 May 1990 Event SCR at ground level or Ground Level Enhancement (GLE) № 47 in the International Classification of 21.05.1990, has been associated with a solar flare of importance 2B/X5.5 and heliocoordinates N34 W37. The onset of type IV radio burst, the probable time of generation of SCR, was noted at 22.12 UT. Fig. la shows the characteristic profiles of increase at two neutron monitor stations: Apatity and Magadan. Profile of Apatity station has the typical for the prompt component (PC) of RSP peak at the beginning of the event. The increase at the Magadan station has a gradual profile, characteristic for the delayed component (DC) of RSP. 99