Small-Scale Structures and Motions of Auroral Signatures as Observed From the Ground: A Planned Field Study Using Camera and Radar Observations

As a continuation of the CASCADES (the Changing Aurora: in Situ and Camera analysis of Electron precipitation Structures) sounding rocket campaign, a ground based study of auroral structures and motions will be conducted this coming winter from Poker Flat, AK. A major goal of this study is to examine the small-scale perpendicular motions of auroral features in the context of auroral poleward boundary activity associated with substorm breakup. The use of an all-sky camera and a narrow-field camera at Poker Flat will allow for a 2-D image of the auroral structures. The narrow-field camera has a 12 X 16 degree field of view and allows for viewing of sub-kilometer scale structures at 100 km altitude, and the all-sky camera provides a large scale auroral context. Ground magnetometers at Poker Flat, Fort Yukon, and Kaktovik provide a view of the 2-D equivalent horizontal current structures associated with the auroral intensification. The 30 MHz imaging radar located in Anchorage will be used to image the same area that is being observed with the narrow-field camera. The SuperDARN radar on Kodiak Island may also be used to view the larger scale auroral activity over AK. The AMISR that is currently being constructed at Poker Flat will give high time and space resolution information on the auroral plasma structures present. Some of the science questions to be addressed with this array of instruments are: How intense are small-scale structures when viewed with high resolution? Does auroral ray size correlate to the perpendicular ray speed? What differences are observed between the motions of adjacent light and dark auroral signatures, and what can this tell us about ionospheric electric fields and plasma density? Can large flow fields exist at very low altitudes on small scales due to ionospheric modification? We are interested in getting feedback from other experimenters and modelers in terms of the relevance of the questions we are trying to address with the camera data as well as with AMISR and its capabilities.