Remote Sensing of Auroral Conductance using Incoherent Scatter Radar and All-sky Imagers

Abstract:

Ionospheric conductance is a key component necessary for characterizing high-latitude electrodynamics at all scale sizes, yet remains difficult to observe directly. Gradients in the local conductance are a key mechanism that support the closure of field-aligned currents. The enhancement of conductance caused by auroral particle precipitation has been difficult to assimilate into global conductance models. Thus, determining the conductance on mesoscale sizes (100s of km) is important for linking local scale sizes (1-10s of km) and global scale sizes (> 1000 km). Incoherent scatter radar is able to obtain high spatially resolved measurements on the local scale sizes, whereas, all-sky imagers are able to obtain mesoscale maps of visible auroral emission. Flexible, rapidly steered ISRs, such as Advanced Modular Incoherent Scatter Radar (AMISR) systems enable imaging of the electron density and conductivities. We present results of case studies from observations taken during the PFISR Ion-Neutral Observations of the Thermosphere (PINOT) campaign to examine the structure of the conductance for stable auroral configurations near magnetic zenith. All sky imager observations are presented which characterize the visible aurora simultaneously observed by the ISR. We discuss the techniques used to take measurements of conductance from the ISR and project them onto the all-sky image. The characteristic energy and energy flux using other techniques are compared against the radar derived characteristic energy and energy flux. We investigate techniques for remotely determining mesoscale conductance using ISR and all-sky imagers to investigate the role conductance has in high-latitude electrodynamics.