Modeling and model-data comparisons of the thermal plasma flows in the midlatitude ionosphere.
详细信息
文摘
Starting from the theoretical work used by the Utah State University time-dependent ionospheric model (TDIM), we have developed a fully coupled ionospheric model (FCIM) that is well suited for examining the F region and the transition to the plasmasphere. The fully coupled ionospheric model adopts the Navier-Stokes system including the energy equations as the basic conservation laws and solves these conservation laws using the flux-corrected transport and the alternating-direction explicit (FCT-ADE) method. Solutions can be described as functions of local solar time and altitude along the real magnetic flux tube ranging from 150 to 3000 km. Discrete values of densities, velocities, and temperatures for O$\sp+$, H$\sp+$, and e$\sp-$ are the major outputs of the FCIM, while the molecular ions, such as NO$\sp+$, O$\sb2\sp+$, and N$\sb2\sp+$, are also solved based on photochemical equilibrium.;Although our original intent was to compare with the Arecibo plasma line data, this research started by comparing the FCIM with the Millstone Hill (MH) incoherent scatter radar data, which were already available. We chose to compare with days that showed an "anomalous" F region density maximum in the late afternoon or early evening. Through a series of model-data comparisons, the major cause of this anomaly was found to be the meridional wind. We also found that the most reasonable set of values for the meridional wind was obtained when a Burnside factor of 1.7, as opposed to 1.0, was used. Using empirical model inputs such as MSISe90 and HWM, and a Burnside factor of 1.7, the FCIM can reproduce the electron density distributions throughout the day within the uncertainty of the geophysical inputs. In addition to the meridional wind, the magnitude of the evening electron density peak was greatly affected by the incident solar flux, i.e., a larger F10.7 correlates with a larger evening peak density, and vice versa.