BALLOON-VIKING DATA ANALYSIS

点击翻译按钮获取中文摘要

The Viking-Balloon campaign in July 1986 was an international collaborative effort and its goal was to utilize correlative measurements from ground, balloon, and space-craft to further understand aurora and the associated magnetospheric processes. The campaign resulted in a wealth of data from many complementary instruments providing an opportunity to study auroral processes from several different perspectives, from global scale to very localized phenomena, involving many relevant parameters - high and low energy particles and electric and magnetic fields - from widely varying regions of space. Preliminary results from the data have already been obtained which indicate interesting structure to pulsating aurora. This grant will support analysis of this extensive data set which has tremendous potential with regard to many magnetospheric-auroral problems. The dynamics of the aurora can be studied from several different regimes, each one distinguished by its characteristic length and time scales. Polar orbiting satellites and rocket experiments have the advantage of making in situ measurements of the local plasma parameters, however the constraints of orbital motion prevent many of these experiments (in particular, rockets and low altitude spacecraft) from making measurements over long time scales. Furthermore there is always an inherent ambiguity in separating spatial effect from temporal effects, due to the single point from which the data is gathered. Satellite imaging of the auroral oval and the polar cap is a powerful tool, but does not always fully elucidate the small scale dynamics occurring within an auroral arc. Balloon borne instruments, however, are able to examine the longer time scale behavior of auroral phenomena, since the balloon's motion is usually much slower than many typical auroral time scales. Furthermore, the space-time ambiguity can be deconvolved by the use of imaging techniques, and multiple point measurements. These imaging techniques allow an examination of structures of scale lengths of order tens of kilometers in as short as a few seconds. This was the general philosophy in the Viking-balloons project; to employ X-ray imaging from a balloon as a tool to understand Polar Ionospheric-Magnetospheric dynamics on time and length scales which are not easily obtainable by other means, and to correlate these measurements to data from a polar orbiting space craft. The Viking satellite from the Swedish Space Corporation provided an opportunity to carry out this experiment. The University of Washington will continue processing and scientific analysis of data obtained during the Viking balloon campaign and take part in coordinated studies with the international group in auroral and magnetospheric dynamics using the Viking-balloon data.