Open AccessExistence of thresholds in proton flares and application to solar energetic particle alerts
Author(s) -
Kubo Yūki,
Akioka Maki
Publication year - 2004
Publication title -
space weather
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 56
ISSN - 1542-7390
DOI - 10.1029/2003sw000022
Subject(s) - flare , solar flare , proton , physics , space weather , flux (metallurgy) , solar cycle 22 , solar cycle 23 , event (particle physics) , solar cycle , coronal mass ejection , solar energetic particles , astrophysics , geostationary operational environmental satellite , satellite , solar cycle 24 , meteorology , astronomy , nuclear physics , plasma , solar wind , metallurgy , materials science
This article discusses our statistical investigations into the occurrence of proton events for solar energetic particle (SEP) alerts in space weather forecasts. We analyzed X‐ray flux and proton intensity data obtained with the GOES satellite in the 23rd solar cycle. We found that the total soft X‐ray flux (1–8Å) of almost all flares related to proton events exceeded a threshold value, which was ∼20 ergs cm −2 . This means that there is a threshold in flare duration in regard to peak X‐ray flux and this is ∼30 min for an M1.0 flare and/or 3 min for an X1.0 flare. We also confirmed this threshold with data in the 22nd solar cycle. These results will provide some of the most important criteria for SEP alerts and solar proton event forecasts in the future.