Dependence of the High-Latitude Ionospheric Fields and Plasma Characteristics on the Properties of the Interplanetary Medium

Abstract

It has now been 16 years since Fairfield and Cahill (1966) and Rostoker and Fälthammar (1967) provided convincing evidence that, as predicted by Dungey (1961), the interplanetary magnetic field (IMF) modulated the transfer of energy from the solar wind to the magnetosphere. In particular, it was evident that the transfer function for the solar-terrestrial interaction was dependent on the direction of the IMF with respect to magnetopause field lines and, to some extent on the solar wind velocity. Rostoker and Fälthammar (1967) suggested that the component of the interplanetary electric field in the ecliptic plane and normal to the sun-earth line (E_ϕ = -v_sB_z where V_s is the solar wind velocity and B_z the component of the IMF parallel or antiparallel to magnetopause field lines) was the best quantitative indicator of the energy transfer and even at the present time it is favored by some researchers dealing with the solar-terrestrial interaction (e.g. Clauer, 1981). In recent years several researchers have attempted to utilize various combinations of solar wind parameters to predict magnetospheric activity levels (as quantified using a_p and AE by Garrett (1973) and using AE by Murayama and Hakamada (1975) amongst others).