Numerical Examination of Akasofu's Energy Coupling Function

Based on the general formula of the energy transfer rate from the solar wind into the magnetosphere, the coupling mechanism of MHD flow is examined by using solar wind data for a period, of 34 days. It is shown that MHD flow mechanism is valid when B_z<0 (or IMF is southward). In this case the energy transfer rate can be expressed by P =CBT^2/3V^5/3n^1/3sin⁴((3/2). This is dfferent from Akasofu's coupling function, but in good agreement with Murayama & Hakamada, Svalgaard, Murayama, and Holzer & Slavin. The factors influencing the calculations of coupling function are also discussed.