ANGEO Annales Geophysicae ANGEO 1432-0576 Copernicus GmbH Göttingen, Germany 10.5194/angeo-22-497-2004 Magnetospheric convection electric field dynamics andstormtime particle energization: case study of the magneticstorm of 4 May 1998 Khazanov G. V. 1 Liemohn M. W. 2 Newman T. S. 3 Fok M.-C. 4 Ridley A. J. 2 National Space Science and Technology Center, NASA Marshall Space Flight Center, Huntsville, Alabama 35899, USA Space Physics Research Laboratory, University of Michigan, Ann Arbor, Michigan 48109, USA Computer Science Department, The University of Alabama in Huntsville, Huntsville, Alabama 35899, USA Laboratory for Extraterrestrial Physics, Code 692, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA 01 01 2004 22 2 497 510 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.ann-geophys.net/22/497/2004/angeo-22-497-2004.html The full text article is available as a PDF file from http://www.ann-geophys.net/22/497/2004/angeo-22-497-2004.pdf

It is shown that narrow channels of high electric field are an effective mechanism for injecting plasma into the inner magnetosphere. Analytical expressions for the electric field cannot produce these channels of intense plasma flow, and thus, result in less entry and adiabatic energization of the plasma sheet into near-Earth space. For the ions, omission of these channels leads to an underprediction of the strength of the stormtime ring current and therefore, an underestimation of the geoeffectiveness of the storm event. For the electrons, omission of these channels leads to the inability to create a seed population of 10-100 keV electrons deep in the inner magnetosphere. These electrons can eventually be accelerated into MeV radiation belt particles. To examine this, the 1-7 May 1998 magnetic storm is studied with a plasma transport model by using three different convection electric field models: Volland-Stern, Weimer, and AMIE. It is found that the AMIE model can produce particle fluxes that are several orders of magnitude higher in the <i>L</i> = 2 – 4 range of the inner magnetosphere, even for a similar total cross-tail potential difference. <br><br><b>Key words.</b> Space plasma physics (charged particle motion and acceleration) – Magnetospheric physics (electric fields, storms and substorms)