Ring current -atmosphere interactions model with stormtime magnetic field
type: CreativeWork
description: An improved version of the ring current-atmosphere interactions kinetic model (RAM) is presented in this thesis. The recent stormtime empirical model T04s and the IGRF model are used to represent the Earth's external and internal magnetic fields respectively. Particle drifts, losses due to charge exchange with geocoronal hydrogen and atmospheric losses are included in the model as they are considered the main mechanisms of ring current development and its following decay. A numerical technique for bounce-averaging along the field lines is introduced and results for the calculated bounce-averaged hydrogen densities and magnetic gradient-curvature drift velocities (general case) for the moderate storm of April 21-25, 2001, are presented. A comparison in the calculations between T04s and a dipole field shows that the bounce-averaged hydrogen density for T04s differs with &sim; 5% from that for a dipole field for quiet time and it may become 30% smaller for disturbed conditions on the nightside for L > 4. The gradient-curvature velocities for T04s at large L-shells are &sim; 20% higher on the nightside and 20% lower on the dayside than those for a dipole field for quiet time. For disturbed conditions they are respectively &sim; 200% higher and 20% lower than the dipole values. The contribution of the cross-B term to the magnetic drift is &sim; 5%. Results for the time evolution of the trapped equatorial flux for H+, He+, and O+ ions for various particle energies and pitch angles obtained by the new model with a non-dipole field (RAM-ND) are presented. The new computations for the April 2001 storm using a Volland-Stern convection model show a slight continued increase in the flux and the total ring current energy for the three ion species even after the storm main phase. A higher increase in the flux is observed towards the dusk side for the RAM-ND model compared to RAM due the difference in the charge exchange rates and the azimuthal drifts for the two different geomagn…
abstract: An improved version of the ring current-atmosphere interactions kinetic model (RAM) is presented in this thesis. The recent stormtime empirical model T04s and the IGRF model are used to represent the Earth's external and internal magnetic fields respectively. Particle drifts, losses due to charge exchange with geocoronal hydrogen and atmospheric losses are included in the model as they are considered the main mechanisms of ring current development and its following decay. A numerical technique for bounce-averaging along the field lines is introduced and results for the calculated bounce-averaged hydrogen densities and magnetic gradient-curvature drift velocities (general case) for the moderate storm of April 21-25, 2001, are presented. A comparison in the calculations between T04s and a dipole field shows that the bounce-averaged hydrogen density for T04s differs with &sim; 5% from that for a dipole field for quiet time and it may become 30% smaller for disturbed conditions on the nightside for L > 4. The gradient-curvature velocities for T04s at large L-shells are &sim; 20% higher on the nightside and 20% lower on the dayside than those for a dipole field for quiet time. For disturbed conditions they are respectively &sim; 200% higher and 20% lower than the dipole values. The contribution of the cross-B term to the magnetic drift is &sim; 5%. Results for the time evolution of the trapped equatorial flux for H+, He+, and O+ ions for various particle energies and pitch angles obtained by the new model with a non-dipole field (RAM-ND) are presented. The new computations for the April 2001 storm using a Volland-Stern convection model show a slight continued increase in the flux and the total ring current energy for the three ion species even after the storm main phase. A higher increase in the flux is observed towards the dusk side for the RAM-ND model compared to RAM due the difference in the charge exchange rates and the azimuthal drifts for the two different geomagn…
author: Vapirev, Alexander Emilov
keywords: Atmospheric Sciences, Physics, Fluid and Plasma
date published: 2007-01-01T08:00:00Z
date modified: 2026-07-24T05:22:19Z
provider: University of New Hampshire
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of New Hampshire