Generation of conic ions by auroral electric fields

Perpendicular accelerations of ions by the auroral electric fields are examined systematically using the test particle approach to assess their contribution to the ion conics observed on high-latitude field lines. The results show (1) that the existence of a nonzero parallel electric field component (E/sub parallel/not =0) is a necessary condition for the static auroral electric fields to accelerate ions continuously across auroral field lines, (2) that the highly nonuniform two-dimensional auroral arc electric fields (with latitudinal thickness L/sub x/< or =rho/sub i/; the ion gyroradius) can contribute to conic ions with energy up to a few keV; (3) that the moderately nonuniform two-dimensional electric field of the inverted V scale (L/sub x/>>rho/sub i/) can contribute to low energy conic ions less than a few tens electron volts, and (4) that the O+ ions can be accelerated across field lines more efficiently than the H+ ions, resulting in more energetic and more coniclike O+ ions than H+ ions