Acceleration Phenomena Observed by Interplanetary Scintillation at 0.1–0.3 AU

Abstract

Interplanetary scintillation has observed high-latitude streams which show low speeds (≤400 km/s) within 0.3 AU and high speeds (≥700 km/s) beyond 0.3 AU. The foot points of these streams were located in the Hel coronal holes or at their boundaries. Since the IPS measurement is biased by one or several mechanisms, we investigated whether this acceleration phenomena could be caused by bias effects or not. Speed increase of more than 100 km/s is left without being explained by the bias effects.