A mathematical model of the middle and high latitude ionosphere

A time-dependent three-dimensional model of the middle and high latitude ionosphere is described. The density distributions of six ion species NO(+), O(2+), N(2+), O(+), N(+), He(+), and the electron and ion temperatures are obtained from a numerical solution of the appropriate continuity, momentum, and energy equations. The equations are solved as a function of height for an inclined magnetic field at E and F region altitudes. The three-dimensional nature of the model is obtained by following flux tubes of plasma as they convect or corotate through a moving neutral atmosphere. The model takes account of field-aligned diffusion, cross-field electrodynamic drifts, thermospheric winds, polar wind escape, energy-dependent chemical reactions, neutral composition changes, ion production due to solar EUV radiation and auroral precipitation, thermal conduction, diffusion-thermal heat flow and local heating and cooling processes. The model also takes account of the offset between the geomagnetic and geographic poles.