The DREAM3D diffusion model is applied to Van Allen Probes observations of the fast dropout and strong enhancement of MeV electrons during the October 2012 "double-dip" storm. We show that in order to explain the very different behavior in the two "dips," diffusion in all three dimensions (energy, pitch angle, and Lo) coupled with data-driven, event-specific inputs, and boundary conditions is required. Specifically, we find that outward radial diffusion to the solar wind-driven magnetopause, an event-specific chorus wave model, and a dynamic lower-energy seed population are critical for modeling the dynamics. In contrast, models that include only a subset of processes, use statistical wave amplitudes, or rely on inward radial diffusion of a seed population, perform poorly. The results illustrate the utility of the high resolution, comprehensive set of Van Allen Probes' measurements in studying the balance between source and loss in the radiation belt, a principal goal of the mission. Key Points DREAM3D uses event-specific driving conditions measured by Van Allen Probes Electron dropout is due to outward radial diffusion to compressed magnetopause Event-specific chorus and seed electrons are necessary for the enhancement.
Geophysical Research Letters
American Geophysical Union Publications
Digital Object Identifier (DOI)
Tu, W., G. S. Cunningham, Y. Chen, S. K. Morley, G. D. Reeves, J. B. Blake, D. N. Baker, and H. Spence (2014), Event-speciﬁc chorus wave and electron seed population models in DREAM3D using the Van Allen Probes, Geophys. Res. Lett.,41, 1359–1366, doi:10.1002/2013GL058819
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