Publication Date:
2015-08-15
Description:
We present a study of the potential radiation hazard of the powerful, superfast interplanetary coronal mass ejection (ICME) observed by STEREO A on 23 July 2012. Using energetic proton flux data from the HET and LET instruments aboard STEREO A together with the EMMREM radiation model, we compute dose rates and accumulated doses during the event for both skin/eye and blood forming organs using four physically relevant levels of shielding. For spacesuit equivalent shielding, we compute a peak skin/eye dose rate of 1970 cGy-Eq/day, a value far greater than those of the 2003 Halloween storms or the January and March SEP events of 2012. However, due to the relative brevity of the event, the resulting accumulated dose was just 383 cGy-Eq, which is more aligned with the total doses of the 2003 Halloween and 2012 January/March events. Additionally, we use dose rates at STEREO B and LRO/CRaTER during the event to show how the radiation impact is affected by the position of the ICME relative to the observer. Specifically, we find that the energetic particle event associated with the local shock and ICME passage at STEREO A caused greatly enhanced dose rates when compared to STEREO B and LRO/CRaTER, which were longitudinally distant from the ICME. The STEREO A/B dose rates used here will soon be made available to the community as a tool for studying the energetic particle radiation of solar events from different longitudes as a part of NASA's Heliophysics Virtual Observatories and on the PREDICCS and CRaTER websites.
Print ISSN:
1539-4964
Electronic ISSN:
1542-7390
Topics:
Geosciences
,
Physics
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