Solar wind structure sources and periodicities of auroral electron power over three solar cycles

We assess the contributions of various types of solar wind structures (transients, coronal hole high-speed streams (HSS), and slow-speed wind) to hourly average auroral electron power (Pe). The time variation of the solar wind velocity (Vsw) and Pe are determined by HSS, which contribute ∼47% to Pe and Vsw. Transients contribute ∼42% of Pe in solar maxima, and ∼6% in solar minimum. Cross-correlations of Pe with Vsw|B| for negative Bz are significant. Pe exhibits solar rotational periodicities similar to those for Vsw, with strong 7- and 9-day periodicities in 2005–2008 and equinox semiannual periodicities in 1995–1999.