© European Geosciences Union 2004
Magnetospheric convection electric field dynamics andstormtime particle energization: case study of the magneticstorm of 4 May 1998
1National Space Science and Technology Center, NASA Marshall Space Flight Center, Huntsville, Alabama 35899, USA
2Space Physics Research Laboratory, University of Michigan, Ann Arbor, Michigan 48109, USA
3Computer Science Department, The University of Alabama in Huntsville, Huntsville, Alabama 35899, USA
4Laboratory for Extraterrestrial Physics, Code 692, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
Abstract. 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 L = 2 – 4 range of the inner magnetosphere, even for a similar total cross-tail potential difference.
Key words. Space plasma physics (charged particle motion and acceleration) – Magnetospheric physics (electric fields, storms and substorms)