Implications of the Stagnation Line Model for energy input through the dayside magnetopause

Based on the formation of a stagnation line at the magnetopause the electromagnetic energy transport from the solar wind into the dayside magnetosphere is analyzed. The resulting energy flux is proportional to v ∞ B ∞ ² sin² (θ ∞ ‐ ϕ ∞ ), where v ∞ and B ∞ are the solar wind speed and magnetic field and θ ∞ ‐ ϕ ∞ is the angle between the IMF and the stagnation line projected into the interplanetary space. A stagnation line parallel to the separator gives approximately the sin 4 (θ ∞ /2) energy flux dependence of Akasofu's ε‐index.