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Relativistic solar neutrons and protons on 28 October 2003
Author(s) -
Bieber John W.,
Clem John,
Evenson Paul,
Pyle Roger,
Ruffolo David,
Sáiz Alejandro
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl021492
Subject(s) - physics , nuclear physics , neutron , solar energetic particles , coronal mass ejection , environmental science , atmospheric sciences , astronomy , astrophysics , solar wind , plasma
The solar cosmic ray event associated with the X17.2 class flare of 28 October 2003 was unusual in several respects: (1) Several high‐latitude neutron monitors observed a large, highly anisotropic spike at event onset. (2) The earliest onset was detected by stations viewing towards the anti‐Sunward hemisphere. (3) The event displayed an extremely slow, protracted decay. (4) The near‐equatorial monitor in Tsumeb, Africa recorded a small increase consistent with a solar neutron event ≈7 minutes prior to the onset at high latitudes. We analyze these signals and infer that relativistic solar neutrons were emitted over a duration of ≈9 minutes, starting ≈7 minutes before the main injection of relativistic protons.