SYNERGISTIC EFFECTS OF HOT PLASMA-DRIVEN POTENTIALS AND WAVE-DRIVEN ION HEATING ON AURORAL IONOSPHERIC PLASMA TRANSPORT

Transverse acceleration by waves and parallel acceleration by field-al igned electric fields are important processes in the transport of iono spheric ions along auroral field Lines. In order to study the transpor t of ionospheric plasma in this environment we have developed a genera lized semikinetic model which combines the tracking of ionospheric ion gyrocenters with a generalized fluid treatment of ionospheric electro ns. Large-scale upward and downward directed electric fields are gener ated within the model by introducing magnetospheric plasma whose compo nents have differing temperature anisotropies. We study the effects of such potentials when combined with the effect of ion heating by a dis tribution of waves along the flux tube. We find that the combination o f wave heating and an upward electric field results in an order of mag nitude increase in O+ outflow (compared to a case with an upward elect ric field and no wave heating). Under these conditions we observe the formation of bimodal conics. When a downward electric field is added t o a case with wave heating, the energy gained by the ions from the wav es increases by a factor of 2 or 3 (over the scenario with wave heatin g and no hot plasma-driven electric field) owing to their slower trans it of the heating region. Typically, the velocity distributions under these conditions are toroids and counterstreaming conics. We also find that the upflowing, dense, heated ionospheric plasma acts to reduce t he potential set up by the anisotropies in the magnetospheric componen ts.