Physics Student Research

Document Type


Journal/Book Title/Conference

American Geophysical Union Fall Meeting

Publication Date



A study has been conducted of the effect that different physical assumptions have on global models of the electron density distribution. The study was conducted with the Ionosphere Forecast Model (IFM) and the Ionosphere Plasmasphere Model (IPM) developed by Utah State University. Both physics-based, time-dependent, global models use the same empirical models for the neutral atmosphere (MSIS) and neutral wind (Horizontal Wind Model, HWM), but the altitude range, thermal structure, number of ion species, and magnetic 2ield are different. The IFM covers the altitude range from 90-1400 km, calculates the densities for four ions (NO+, O2+, N2+, O+), has a simple prescription for calculating H+, and is based on a tilted offset dipole magnetic 2ield. The IPM extends from 90-20,000 km, includes six ion species (NO+, O2+, N2+, O+, H+, He+), is based on the International Geomagnetic Reference Field (IGRF), and allows for inter-hemisphere 2low. Therefore, the comparison of these models will elucidate the quantitative effect of these differences. In addition, simulations were conducted to study the effect of uncertainties in the zonal wind, secondary electron production, O+/ O collision frequency, tidal structure, and state of plasmasphere re2illing. The simulations were conducted for a wide range of solar, seasonal, and geomagnetic activity levels. Quantitative results will be given that establish the importance of the various physical processes.


Poster presented at the AGU Fall Meeting, December 13-17, 2010. PDF of poster is available for download through link above.