Proton energy spectrum and source parameters of the September 29, 1989 event

Vashenyuk, E.V. and Miroshnichenko, L.I. and Gvozdevsky, B.B. (2000) Proton energy spectrum and source parameters of the September 29, 1989 event. Il nuovo cimento C, 23 C (3). pp. 285-292. ISSN 1826-9885

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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 (RF1 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 A1-2 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 = 1.23107 cm23 ; 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.

Item Type: Article
Uncontrolled Keywords: Cosmic rays
Subjects: 500 Scienze naturali e Matematica > 550 Scienze della Terra > 551 Geologia, Idrologia, Meteorologia > 551.5 Meteorologia (Classificare qui l'atmosfera) (Classificare la previsione e le previsioni di specifici fenomeni meteorologici in 551.64; classificare la Micrometeorologia in 551.66) > 551.52 Termodinamica, interazioni atmosferiche con la superficie terrestre, temperature, radiazioni > 551.527 Radiazioni (per fenomeni ottici, vedi 551.565) > 551.5276 Radiazioni cosmiche (Include il rumore cosmico) (Classificare qui i raggi cosmici)
Depositing User: Marina Spanti
Date Deposited: 09 Mar 2020 14:58
Last Modified: 09 Mar 2020 14:58

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