Proton energy spectrum and source parameters of the September 29, 1989 eventстатья
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Дата последнего поиска статьи во внешних источниках: 27 мая 2015 г.
Аннотация:Résumé / Abstract
Ground Level Enhancement (GLE) of solar cosmic rays (SCR) widely observed on September 29, 1989 is studied. The event was remarkable for a number of unusual features. Among them were the double-peak increases observed at some neutron monitor (NM) stations and complicated behaviour of the proton energy spectrum and anisotropy at high rigidities (R≥ 1 GV). Two-component structure of the proton intensity-time profiles in the event has been demonstrated. The first (prompt) component (PC) had a short duration and very hard energy spectrum. The second (delayed) component (DC), being ejected from the Sun ∼1-2 h later, was dominated by a particle population with the soft spectrum and gradual profiles. By fitting the observed proton spectrum to the calculated one in a computational model with a fast acceleration mechanism at the first, early stage of the event, we estimate parameters of the magnetic field and plasma in the source of the prompt component: B = 91 G; n=1.2 ×107 cm-3; L=109 cm (B, n and L are magnetic field intensity, plasma density at the acceleration site and length of the current sheet, respectively). Such values of B and n are characteristic for the trailing part of coronal transient (behind an eruptive filament) at the coronal heights of several tenths of solar radius, and the value of L is of the order of the filament length.