Analysis of the ground level enhancements on 14 July 2000 and on 13 December 2006 using neutron monitor data

Abstract

On the basis of neutron monitor data we estimate the energy spectrum, anisotropy axis direction and pitch-angle distribution of solar energetic particles during two major ground level enhancements (GLE 59 on 14 July 2000 and GLE 70 on 13 December 2006). For the analysis we use a newly computed neutron monitor yield function. The method consists of several consecutive steps: definition of the asymptotic viewing cones of neutron monitor stations considered for the data analysis by computations of cosmic ray particles propagation in a model magnetosphere with the MAGNETOCOSMICS code; computation of the neutron monitor model responses and derivation of the solar energetic particle characteristics on the basis of inverse problem solution. The pitch-angle distribution and rigidity spectrum of high-energy protons are obtained as function of time in the course of ground level enhancements. A comparison with previously reported results is performed and reasonable agreement is achieved. A discussion of the obtained results is included as well their possible application is included.

arXiv comment23 pages, 9 figures, 3 tables; Accepted for publication in Solar Physics

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• Properties of Ground Level Enhancement Events and the Associated Solar Eruptions during Solar Cycle 23
• GeV Particle Acceleration in Solar Flares and Ground Level Enhancement (GLE) Events
• Neutron Monitor Yield Function: New Improved computations
• An Improved Model for Relativistic Solar Proton Acceleration applied to the 2005 January 20 and Earlier Events
• Relativistic Proton Production During the 14 July 2000 Solar Event: The Case for Multiple Source Mechanisms

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