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

Abstract

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 ( P e). The time variation of the solar wind velocity ( V sw) and P e are determined by HSS, which contribute ∼47% to P e and V sw. Transients contribute ∼42% of P e in solar maxima, and ∼6% in solar minimum. Cross-correlations of P e with V sw|B| for negative B z are significant. P e exhibits solar rotational periodicities similar to those for V sw, with strong 7- and 9-day periodicities in 2005–2008 and equinox semiannual periodicities in 1995–1999.