Temporal and spatial evolution of the solar energetic particle event on 20 January 2005 and resulting radiation doses in aviation
Artikel i vetenskaplig tidskrift, 2009

The solar energetic particle event on 20 January 2005 was one of the largest ground level events ever observed. Neutron monitor stations in the Antarctic recorded count rate increases of several thousand percent caused by secondary energetic particles, and it took more than 36 h to return to background level. Such huge increases in high energetic solar cosmic radiation on the ground are obviously accompanied by considerable changes in the radiation environment at aviation altitudes. Measurements of 28 neutron monitor stations were used in this work to numerically approximate the primary solar proton spectra during the first 12 h of the event by minimizing the differences between measurements and the results of Monte-Carlo calculated count rate increases. The primary spectrum of solar energetic protons was approximated by a power law in rigidity and a linear angular distribution. The incoming direction of the solar energetic particles was determined and compared to the interplanetary magnetic field direction during the event. The effects on the radiation exposure at altitudes of about 12 km during that time were estimated to range from none at low latitudes up to almost 2 mSv/h for a very short time in the Antarctic region and about 0.1 mSv/h at high latitudes on the Northern Hemisphere. After 12 h, dose rates were still increased by 50% at latitudes above 60 degrees whereas no increases at all occurred at latitudes below 40 degrees during the whole event.

10 tev

neutrons

cosmic-rays

shock acceleration

fluence

flare

latitude

conversion coefficients

abundances

magnetic-fields

Författare

D. Matthia

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Christian-Albrechts-Universität zu Kiel

B. Heber

Christian-Albrechts-Universität zu Kiel

G. Reitz

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

M. Meier

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Lembit Sihver

Chalmers, Teknisk fysik, Nukleär teknik

T. Berger

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

K. Herbst

Christian-Albrechts-Universität zu Kiel

Journal of Geophysical Research

0148-0227 (ISSN)

Vol. 114 8 A08104 (art no)-

Ämneskategorier

Fysik

DOI

10.1029/2009JA014125

Mer information

Senast uppdaterat

2018-05-29