COMPARISON BETWEEN CALCULATED AND OBSERVED F-REGION ELECTRON-DENSITY PROFILES AT JICAMARCA, PERU

Electron density profiles and isodensity contours derived from Jicamar ca incoherent scatter radar observations in Peru for October 1-2, 1970 , are compared in detail with results from the Phillips Laboratory glo bal theoretical ionospheric model. This model solves the ion continuit y equation for O+ concentration through production, loss, and transpor t of ionization. The primary factor controlling the peak plasma densit y at Jicamarca is the vertical E x B drift, which drives the ionizatio n upward during the day and downward at night. When we use the measure d drift in the model, we achieve excellent results with the measured e lectron density profiles. We illustrate the sensitivity of the low-lat itude plasma density calculations to changes in the vertical E x B dri ft and changes in the neutral winds. We also compare the calculated pr ofiles and peak parameters with an empirical model, the International Reference Ionosphere (IRI). We illustrate several limitations associat ed with the IRI that contribute to its limited capability at the magne tic equator.