The New JPL Interplanetary Solar High-Energy Particle Environment Model
Abstract
The high-energy protons and heavy ions from solar energetic particle (SEP) events present hazard to space systems: damage to science instruments/electronics or to astronauts. A reliable estimate of the high-energy particle environment is very important to assure the mission success. Without it, system survivability is often ensured by setting grossly over-conservative mission requirements, resulting in high mission costs, weight and physically large systems. However, at present our ability to reliably predict the space environments for missions not shielded by planetary magnetic fields is surprisingly poor, especially for missions not at 1 AU. The primary reasons for this are that: (1) SEP events are infrequent and sporadic, (2) statistically valid data exist only at 1 AU, and (3) radial dependence of SEP fluxes and fluences is still to be determined. Our ultimate goal is to develop an advanced model that can reliably provide statistical estimates of mission- integrated fluences of SEP high-energy protons and heavy ions for arbitrary trajectories, launches on arbitrary future dates, and an improved radial dependence law. This will be achieved by adopting an approach used in a preliminary Solar Probe mission study, that is, by flying a spacecraft through the database (described below) with an appropriate radial dependence law being applied at each time step. Here we present the preliminary results for a high-energy "proton" model. For the study, we use the data obtained from the instruments onboard the IMP-8 spacecraft: Goddard's Low Energy Detector (LED) and Medium Energy Detector (MED) and the University of Chicago's Cosmic Ray Nuclear Composition (CRNC) telescope. The data set covers the period between 1973, day 305, and 1997, day 319, at 1 AU. All the data were averaged over 6- hour intervals and corrected for background by subtracting non-SEP contributions (i.e., contributions from galactic cosmic rays and spurious instrumental effects).
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFMSH51A1468J
- Keywords:
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- 7514 Energetic particles (2114)