Reprints available upon request
Previous studies have shown that most ion conics in the auroral zone are associated with either broad-band extremely low frequency (BBELF) or electromagnetic ion cyclotron (EMIC) emissions. EMIC emissions are correlated with preferential acceleration of He+ but are concentrated in the pre-midnight sector; BBELF emissions are found at all local times but are not associated with preferential acceleration of any species. We present a case study of five auroral passes which show both wave emissions associated with ion conics at different locations. Our data indicate that EMIC waves can be locally important for accelerating outflowing He+ in the aurora. However, although this study's design exaggerates the contribution of EMIC waves to transverse ion acceleration, we find in each case that BBELF waves produce higher energy fluxes of upflowing ions. Therefore, events with BBELF emissions dominate the overall ion outflow.
[Key Figure | Publications | Home]