HR: 16:00h
AN: SM14B-01 INVITED    [Abstracts]
TI: New insights on radiation belt physics from global data assimilation models
AU: * Reeves, G D
EM: reeves@lanl.gov
AF: Los Alamos National Lab., Mail Stop D-466 Space Sciences, ISR-1, Los Alamos, NM 87544,
AB: As we have progressed toward an integrated, predictive space weather system, space physics has undergone dramatic changes in both our understanding of the underlying physics and in the methods used to develop that understanding. Radiation belt dynamics and their connection to the broader heliophysical system are a powerful example. In recent decades a shift from single spacecraft observations to multi-spacecraft systems analysis precipitated fundamental changes in our understanding of radiation belt physics. Variations in intensity by many orders of magnitude were observed throughout the system on time scales as short as minutes. The connection between radiation belt events and geomagnetic storms was revealed to be both more complex and less predictable than previously imagined. Simple drivers such as high speed streams evolved into comparative studies of heliospheric structures such as CMEs and CIRs. As a result, new theories of diffusion and wave- particle interactions were developed to explain radiation belt acceleration, transport, and losses. Now, a different analysis methods based on application of the techniques of data assimilation are able to test and develop highly sophisticated, physics-based models of the radiation belts and the coupled inner magnetosphere system. Data assimilation-based modeling not only provides a specification of the global state of the magnetosphere but also provides tools for understanding the dynamics, testing specific theoretical predictions, and developing more complete (but still physically constrained) radiation belt models. In this paper we discuss how data assimilation- based radiation belt models are being used by different research groups to develop new physical insights and improved models. We will also highlight recent results from the DREAM model that test the effects of magnetopause shadowing, electron precipitation, the Dst effect, and VLF wave-particle acceleration.
DE: 2720 Energetic particles: trapped
DE: 2730 Magnetosphere: inner
DE: 2753 Numerical modeling
DE: 2774 Radiation belts
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting