Estimation of Energy Input during Throat Aurora Processes

The throat aurora is a kind of discrete auroras occurred around the Magnetic Local Noon (MLN). The discrete arc is almost vertical to the auroral oval and extends equatorward. Previous studies have shown that the throat auroral structure corresponds to the localized magnetopause indentations which are related to the particular magnetopause reconnection. As is known, magnetic reconnection is the important approach inputting energy of solar wind, so the research of energy input of throat aurora is key to understand this particular magnetopause reconnection. A new way to estimate the energy input by using all auroral events happened on December 2015 is built. A relational expression about auroral intensity and energy flux of electronic precipitation is set up by observations of both ground station and satellite. Estimating the total energy input of a typical throat auroral event which lasted three minutes and happened on 8 December 2015 by this relational expression, and the answer is about $ 1.07\times {10}^{11}\;\mathrm{J} $. And the average power of input energy per area is about $ 1.31\times {10}^{-4}\;\mathrm{W} \cdot {\mathrm{m}}^{-2} $. Compared with the usual polar gap energy input results given by MHD simulation in previous studies, the energy input efficiency of the throat auroral process given in this paper is about twice that of the MHD simulation results, which indicates that the energy input accompanying the throat auroral process is very considerable and may cause local space weather effects.