1. Alexander Mishev and Ilya Usoskin
Using global neutron monitor network data for GLE analysis: recent results
Alexander Mishev and Ilya Usoskin
University of Oulu

2. Outline 1. Introduction & Motivation
2. NM yield function, method for GLE analysis
3. sub-GLE analysis
4. Examples
5. Summary

3. 3
Introduction
An important topic of solar physics, space weather, atmospheric physics is the assessment
Primary SEP parameters:
energy spectrum
anisotropy
using the information from NMs

4. Global neutron monitor network

5. Method for GLE analysis
The NM count rate modeling
NM yield function
NM rel. increase

6. New NM yield function Mishev, Usoskin & Kovaltsov JGR,2013, 118, 2783-2788

7. The GLE analysis procedure
1. Definition of asymptotic viewing cones and Pc of the NM stations:
Computation of particle trajectory in a model magnetosphere.
2. making an initial guess of the inverse problem
3. Application of a optimization procedure (inverse method)
primary solar proton parameters:
(energy spectrum, anisotropy axis direction, pitch-angle distribution)

8. Modified power law or exponent
PAD – Gaussian like
From 5 Up to 14 parameters

9. Inverse, constrained nonlinear problem
Levenberg Marquardt algorithm using MINPACK

10. Rigidity spectrum and PAD during GLE 70, 13 December 2006

11. GLE 70 –

12. GLE 70 –

13. Contour plot for best fit solution vs
Contour plot for best fit solution vs. geo latitude and longitude (18:00 UT)

14. Asymptotic viewing directions during GLE 67, 2 November 2003

15. Rigidity spectra during GLE 67, 3 November 2003
Initial & main phase
17:30—17:55
Late phase
18:00—18:30

16. PAD during GLE 67, 3 November 2003

17. Rigidity spectra during GLE 71, 17 May 2012

18. PAD during GLE 71, 17 May 2012

19. Sub-GLE event of 29 October 2015 contour plot

20. Derived family of spectra and PAD sub-GLE 29 October 2015

21. Conclusion 1. New NM yield function
2. Method for GLE analysis based on NM data
3. Method for sub-GLE analysis based on NM data

22. THANK YOU