On the correlation between a magnetopause penetration parameter and FTE occurrence

Impulsive plasma penetration has been proposed as a means by which solar wind plasma may cross the magnetopause and enter the magnetosphere. It has been predicted that plasma entry by this means will be correlated with a magnetopause penetration parameter. One of the most important signatures of plasma entry into the magnetosphere are flux transfer events (FTEs). If plasma penetration is an important mechanism in plasma entry, then it would be expected that the occurrence of flux transfer events will correlate with the penetration parameter. On the other hand, if reconnection is, as widely believed, the dominant mechanism for the entry of solar-wind plasma into the magnetosphere, then plasma entry will be correlated with the north/south IMF component. AMPTE UKS data show that the occurrence of FTE signatures is better correlated with the direction of the IMF than with the penetration parameter. Thus, impulsive plasma penetration is unlikely to be the mechanism responsible for FTEs.