Auroral precipitating energy during magnetic storms associated with HILDCAAs

HILDCAA (High Intensity Long Duration Continuous AE Activity) events produce intense and long-duration auroral activity. The power energy input carried by precipitating electrons into the auroral zone is an important parameter for understanding the energy transfer processes between the solar wind and the magnetosphere/ionosphere. We have used auroral images provided by the Ultraviolet Imager (UVI) on board Polar satellite to obtain quantitative information about the energy source during magnetic storms associated and non-associated with HILDCAAs. We have estimated the energy of the auroral precipitating particles during the events. In order to obtain accurate energy values, we developed a dayglow estimate method to remove solar contamination from the UVI images, before performing the energy computation. Our results have shown that the auroral energy is highly fluctuating during magnetic storms associated with HILDCAAs.