文档介绍：Solar aspects of papers
THE OCCURRENCE PROBABILITY AND THE MAIN REGULAR FEATURES OF SOLAR ENERGETIC PARTICLE EVENTS AND FLUXES
Skobeltsyn Institute of Nuclear Physics, Moscow State University, Vorobyovy Gory, Moscow, 119992, Russia
ABSTRACT
The solar energetic particle fluxes, which occur sporadically in the Earth orbit, constitute an important factor of space weather. Despite the probabilistic nature of the solar energetic particle occurrences in the Earth orbit, they show quite a number of regular features that (if known) make it possible to predict the solar energetic particle flux sizes expected within a given probability for a given period of an expected solar activity level.
There exist two main regular features, namely,
the mean solar energetic particle event occurrence frequency at any solar activity level is proportional to sunspot number;
when normalized to a unified solar activity level, the solar energetic particle distribution function is independent of (invariant to) solar activity.
All the present-day experimental data on the number of solar energetic particle events, on the sizes of proton peak fluxes, and on the event cumulative fluences agree properly with the calculation results obtained basing on the above regular features.
INTRODUCTION
The occurrence frequency of the solar energetic particle (SEP) events is known to vary with changing solar activity. Namely, the SEP event occurrences are rare during solar minima and are more and more frequent as solar activity increases. During the rising solar activity period, the numerous SEP events include those with up to 109 proton/cm2 and even more protons of energies above 30 MeV.
Pursuing determination of the regular features of the SEP event occurrences, which are explicitly of statistical nature, we must answer the following questions in terms of a strict mathematics.
(1) What is the dependence of the SEP event occurrence frequency on solar activity level? Is the dependence