Auroral Arc Lifetimes and the Stationary Inertial Alfv\'{e}n Wave*

Images from the NORSTAR array of All-Sky-Imagers are used to analyze discrete auroral arcs by observing optical emission of the arcs from formation through breakup. 2-D images of the aurora, collected by All-Sky-Imagers at three sites across Canada, have been analyzed to define the lifetime of a discrete auroral arc. This poster presents a frequency distribution of auroral arc lifetimes and the statistics of other temporal quantities defined in this study (e.g., duty cycle of a given structure). The prevalence of long-lived static arcs in this study is contrasted with the lack of a complete theory to explain these statistics. We suggest that this prevalence is consistent with the laboratory-observed and predicted properties of the Stationary Inertial Alfv\'{e}n Wave, a non-fluctuating, non-travelling, spatially periodic pattern in electromagnetic field and fluid quantities that arises in the simultaneous presence of a magnetic-field-aligned current channel and cross-magnetic field plasma flow [1,2].\\[4pt] [1] D.J. Knudsen, J. Geophys. Res. \textbf{101}, 10761, 1996;\\[0pt] [2] S.M. Finnegan, et. al., Phys. Plasmas. \textbf{15}, 052108, 2008.