Astronomy and Astrophysics – Astrophysics
Scientific paper
Oct 2009
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009jgra..11410105j&link_type=abstract
Journal of Geophysical Research, Volume 114, Issue A10, CiteID A10105
Astronomy and Astrophysics
Astrophysics
3
Ionosphere: Solar Radiation And Cosmic Ray Effects, Solar Physics, Astrophysics, And Astronomy: Solar Activity Cycle (2162), Solar Physics, Astrophysics, And Astronomy: Coronal Mass Ejections (2101), Interplanetary Physics: Solar Cycle Variations (7536), Space Weather: Solar Effects
Scientific paper
Solar energetic particle events (SEPEs) can exhibit flux increases of several orders of magnitude over background levels and have always been considered to be random in nature in statistical models with no dependence of any one event on the occurrence of previous events. We examine whether this assumption of randomness in time is correct. Engineering modeling of SEPEs is important to enable reliable and efficient design of both Earth-orbiting and interplanetary spacecraft and future manned missions to Mars and the Moon. All existing engineering models assume that the frequency of SEPEs follows a Poisson process. We present analysis of the event waiting times using alternative distributions described by Lévy and time-dependent Poisson processes and compared these with the usual Poisson distribution. The results show significant deviation from a Poisson process and indicate that the underlying physical processes might be more closely related to a Lévy-type process, suggesting that there is some inherent “memory” in the system. Inherent Poisson assumptions of stationarity and event independence are investigated, and it appears that they do not hold and can be dependent upon the event definition used. SEPEs appear to have some memory indicating that events are not completely random with activity levels varying even during solar active periods and are characterized by clusters of events. This could have significant ramifications for engineering models of the SEP environment, and it is recommended that current statistical engineering models of the SEP environment should be modified to incorporate long-term event dependency and short-term system memory.
Gabriel Stephen B.
Jiggens T. A. P.
No associations
LandOfFree
Time distributions of solar energetic particle events: Are SEPEs really random? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Time distributions of solar energetic particle events: Are SEPEs really random?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Time distributions of solar energetic particle events: Are SEPEs really random? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1515683