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1. Title NMDB meeting Kiel, Germany, 3-8 December, 2008 Real time GLE modeling and Relativistic Solar Cosmic Ray parameters deriving E.V.Vashenuyk, Yu.V.Balabin, B.B.Gvozdevsky Polar Geophysical Institute Apatity, Russia

2. Real time operating GLE alerting systems: • 1. T Kuvabara, J.W.Bieber, P.Evenson, R.Pyle, et al., Real time cosmic ray monitoring system for space weather. Space weather, V.4, 2006, • H.Mavromichalaki, G.Souvatzog,lou, C.Sarlanis, G.Mariatos, M. Gerontidou, A.Papaioannu, C.PAnn. Geophys. 23, 3103, 2005lainaki, S.Tatsis, A.Belov, E.Eroshenko, and V.Yanke. The new Athens center on data processing from the neutron monitor network in real time.

3. The GLE onset detected.. • Next we want to know the solar cosmic ray characteristics, to estimate the hazardous consequents. But deriving SCR parameters from the neutron network data is not an easy task. The problem becomes more complicated if one has to solve it for the limited time and at the limited number of stations. As we face in a case of the NMDB

4. OUTLINE • Neutron monitor network as an instrument for relativistic solar cosmic ray studies and GLE modeling technique • Results of relativistic solar cosmic ray events study with the GLE modeling • Real time GLE modeling in frames of NMDB project. Approaches to the problem

5. Variations of cosmic ray intensity as recorded by the neutron monitors with solar activity. By black triangles are shown GLE occurrences.

6. Asymptotic Cone of Acceptance is formed by trajectories of particles contributing into response of NM Effect of magnetosphere on cosmic rays Barentsburg is a high-latitude station and accepts radiation from high latitudes of the selestial sphere and a subpolar station Apatity from equatorial latitudes 5

7. Anisotropy Solar cosmic rays anisotropy effect during the GLE on December 13, 2006 Apatity (10 s data) Barentsburg (1 min) 6

8. Set of NMs The worldwide network of neutron monitors as a multidirectional cosmic ray spectrometer 7

9. GLE modeling techniqueof deriving the characteristics of relativistic solar protons (RSP) from the neutron monitor network data consists of a few steps: 1. Definition of asymptotic viewing cones (taking into account not only vertical but also oblique incident on a detector particles) by the particle trajectory computations in a model magnetosphere (Tsyganenko 2002) 2. Calculation of the NM responses at variable primary solar proton flux parameters. 3. Application of a least square procedure for determining primary solar proton parameters (namely, energy spectrum, anisotropy axis direction, pitch-angle distribution) outside the magnetosphere by comparison of computed ground based detector responses with observations

10. Method: 8 direct. Scheme of asymptotic cones calculations: To account the contribution of oblique incident particles we calculate 8 trajectories of particles launched at zenith angle 20o and 8 azimuths Asymptotic directions at magnetopause SCR GCR ~20° Starting directions at a launching point Calculated asymptotic directions are then used inthe following modeling of a NM response 9

11. The response function of a i-th neutron monitor to anisotropic flux of solar protons. • (dN/N)i is percentage increase effect at a given neutron monitor i • J(R) = JoR-*is rigidity spectrum of RSP fluxwith changing slope • * =  +  ·(R-1) where  is increase per 1 GV (Cramp et al., 1997) • S(R) is specific yield function (Debrunner et al., 1984), • θ(R) is pitch angle (angle between the anisotropy axis given • by;  parameters) • F(θ(R )) ~ exp(-θ2/C)is pitch-angle distribution in a form of Gaussian (Shea&Smart, 1982) Formula 8

12. Thus, 6 parameters of anisotropic solar proton flux outside magnetosphere ; , Jo, , , C are to be determined by a solving of the nonlinear least square problemby comparison of computed responses with observations As example of such study we consider the last GLE on December 13, 2006.

13. Increase profilesat some NM stations: Oulu, Apatity, Moscow, Barentsburg, Fort Smith GLE 70 13.12.2006 GLE 70 The asymptotic cones (1-20 GV), for the above NM stations and Th-Thule, McM-McMurdo, SA-SANAE, Ma-Mawson, No-Norilsk, Ti-Tixie, CS-Cape Shmidt, In-Inuvik, Pe-Pewanuk. The derivedanisotropy axis and pitch angle grid lines for solar proton flux at 03.00 UT are shown. The cross is the IMF direction (ACE data). 9

14. Fitting Observed and modeled responses at a number neutron monitor stations ───increase profiles at neutron monitors ●●● modeling responses

15. Dynamics of pitch angle distributions (PAD) derived from neutron monitors data 5 to Sun 1 3 3 1 2 Numbers mark the moments of time 4 PAD demonstrates an initial highly collimated beam of particles (prompt component) followed by a delayed quasi-isotropic population (delayed component) 5 6

16. Peak Peak caused by the prompt component of relativistic solar protons (Buetickofer &Flueckiger, 2006) Calculated magnetopause projection of the beam, registered by the Hodoscope MEPHI (blue spot). Asymptotic cones of NM stations (on the left) are shown. Neutron monitors Hodoscope MEPHI observation of collimated particle flux: D. A. Timashkov, Yu.V. Balabin, V. V. Borog, K. G. Kompaniets, A. A. Petrukhin,E.V.Vashenyuk et al, 30icrc, paper 0298

17. Dynamics of energetic spectra of relativistic solar protons GLE 70

18. GLE 20.01.2005 Increase profiles as registered by a number of NM stations and EAS array “Carpet”(Baksan, North Caucasus) The spectrum derived in moment (1 ) when the promptcomponent was dominated is exponentialin energy: J= 1.5105exp(-E/0.92), and spectrum of delayedcomponent (2) has a power-law form: J = 7.5104 E-4.9. (Vashenyuk et al.2006, 2007, Perez-Peraza et al., 2008)

19. Exponential spectrum of the prompt component was a cause of a giant increase effect at McMurdo neutron monitor and power law spectrum of delayed component produced rather moderate effect at this and other NM stations during the GLE 20.01.2005 SYF- specific yield function Debrunner et al., 1984 a c b d Increase profiles at the McMurdo and Mawson neutron monitors (a), rigidity spectra derived at the moments 07:00 (1) and 08:00 (2) UT (b), SYF and spectra 1 and 2 (c); differential responses (d) of the McMurdo neutron monitor to the exponential spectrum at the moment 1 (blue shading) and to the power-law spectrum at themoment 2 (red shading).

20. Two relativistic solar proton components in the GLE 23 February, 1956 (a)Increase profiles at the Leeds and Ottawa neutron monitors; (b) energy spectra derived at the moments 04:00 (1) and 06:00 UT (2), (c) SYF and spectra (1 and 2) and differential responses of the Leeds neutron monitor to the exponential spectrum (1,blue) and to the power-law spectrum (2,red). By numbers are marked, respectively,the moments when the prompt component (1) or delayed one (2) were dominating. One can see comparable responses of both neutron monitors to the power-law spectrum at moment (2).

21. Results of modeling analysis of 22 major GLEs showing existence of two RSP components Spectrum of prompt component: J=J0exp(E/E0), E (GeV); J0, J1 (m2 s st GeV) -1 Spectrum of delayed component J=J1E-γ E.V. Vashenyuk, Yu.V. Balabin, L.I. Miroshnichenko J. Perez-Peraza , A. Gallegos-Cruz3, 30 icrc, Merida, Mx, paper 0588

22. Prompt and delayed components of relativistic solar protons (RSP) • The modeling analysis of 22 large GLEs occurred in the period 1956-2006 on the data of the worldwide neutron monitors carried out by us revealed two distinct RSP populations (components): • Prompt Component (PC): the early collimated impulse-like intensity increase with exponential energy spectrum, • Delayed component (DC): the late quasi-isotropic gradual increase with a softer energy spectrum of the power law form. • The exponential spectrum may be an evidence of the acceleration by electric fields arising in the reconnecting current sheets in the corona. The possible source of delayed component particles can be stochastic acceleration at the MHD turbulence in expanding flare plasma. • E.V. Vashenyuk, Yu.V. Balabin, L.I. Miroshnichenko J. Perez-Peraza , A. Gallegos-Cruz,J ASR, V.38 (3), 411; (2006); 30 icrc, Merida, Mexico, paper 0658(2007)

23. Spectra of prompt and delayed solar proton components derived from neutron monitor data for a number of GLEs Delayed component Prompt component GLE No GLE No Points are direct solar proton data from spacecrafts and balloons Spectra of the prompt component as a rule have exponential dependence upon energy Spectra of the delayed component have close to the power law dependence upon energy

24. Spectra of prompt and delayed solar proton components derived from neutron monitor data for a number of GLEs Delayed component Prompt component GLE No GLE No PC 20.01.05 PC 20.01.05 Points are direct solar proton data from spacecrafts and balloons Spectra of the prompt component as a rule have exponential dependence upon energy Spectra of the delayed component have close to the power law dependence upon energy

25. Focusing effect of geomagnetic field Asymptotic cones calculated for particles launched under inclined directions. Focusing effect is seen for rigidities from 1 to 5-10 GV

26. Stations

27. Cut model,NMDB stations only • APTY • ATBA • ATHN • BKSN • BRBG • CAPS • IRKT • JUNG • KERG • KIEL • LARC • LMKS • MGDN • MOSC • NRLK • NVBK • OULU • TXBY • YKTK

28. Spectra derived at 3.55, 400 and 4.20 UT. Dashed curves: full model, solid curves- the cut one

30. Results of GLE 70 modeling by the full and cut models