Incoherent Scatter Radar-FAST Satellite Common Volume Observations of Upflow-to-Outflow Conversion

Abstract

Incoherent scatter radar measurements from the Sondrestrom Research Facility and the European Incoherent Scatter Svalbard radar have been combined with all-sky images, polar convection measurements, and FAST particle and field measurements to quantify the contribution of different magnetosphere-ionosphere coupling processes to the extraction efficiency of ions from the ionosphere. Upflowing ions are traced from their source vertically and horizontally to determine where and when they are likely to intersect the acceleration region observed by FAST. The duration and location of auroral emissions are used to estimate the size and duration of the acceleration region. The upflow-to-outflow efficiency is estimated for three periods of polar cap boundary intensifications and streamers during substorm recovery and steady magnetospheric convection. The extraction efficiency of conics ranges between 0.1%, for the lowest amplitude of broadband extremely low frequency waves, and 5%, for the highest-amplitude waves sampled. Simultaneous measurements of all-sky images and magnetic field-aligned radar measurements show that the most intense ion upflux occurs adjacent to the boundary of intense electron precipitation characteristic of polar cap boundary intensifications and streamers, suggesting that the most efficient acceleration mechanisms couple ionospheric heating at F region altitude with dispersive Alfvén waves that grow from horizontal gradients in electric field and conductivity.