American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article (file size: 1167261 bytes)    Cited by

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, A11S08, doi:10.1029/2006JA011609, 2006

Evolution of the proton ring current energy distribution during 21–25 April 2001 storm

N. Y. Ganushkina

Finnish Meteorological Institute, Space Research Division, Helsinki, Finland


T. I. Pulkkinen

Finnish Meteorological Institute, Space Research Division, Helsinki, Finland


A. Milillo

Istituto di Fisica dello Spazio Interplanetario, Rome, Italy


M. Liemohn

Space Physics Research Laboratory, University of Michigan, Ann Arbor, Michigan, USA


Abstract

Three ring current models are used to follow the evolution of the proton ring current during the 2001-04-21–25 storm: The ring current model combined with tracing particles numerically in the drift approximation by Ganushkina et al. (2005), the empirical model of proton fluxes in the inner magnetosphere developed by Milillo et al. (2003), and the kinetic ring current-atmosphere interaction model (RAM) by Liemohn et al. (2001). The paper focuses on the effects of the electric and magnetic field models and initial particle distributions on the final energy distribution. We examine a variety of large-scale magnetic field and convection electric field models as well as substorm-associated, smaller-scale, and time-varying electric fields. We find that (1) using more realistic magnetic field models leads to reduction of the ring current energy content by ∼30%; (2) details of the global convection field have little influence on the overall ring current evolution; (3) smaller-scale impulsive electric field have profound effects on the ring current evolution, particularly with regard to the acceleration of the higher-energy particles; and (4) in the ring current models, the choice of the initial and boundary conditions have significant effects on the modeled ring current intensity and energy spectrum.

Received 11 January 2006; accepted 14 August 2006; published 11 October 2006.

Keywords: drift model; magnetic storm; ring current.

Index Terms: 2788 Magnetospheric Physics: Magnetic storms and substorms (7954); 2760 Magnetospheric Physics: Plasma convection (2463); 2778 Magnetospheric Physics: Ring current; 2753 Magnetospheric Physics: Numerical modeling.

Read Full Article (file size: 1167261 bytes)    Cited by

Citation: Ganushkina, N. Y., T. I. Pulkkinen, A. Milillo, and M. Liemohn (2006), Evolution of the proton ring current energy distribution during 21–25 April 2001 storm, J. Geophys. Res., 111, A11S08, doi:10.1029/2006JA011609.