Variability in the Electrodynamics of the Small Scale Auroral Arc

A statistical study has been made of dynamic small‐scale auroral events in order to understand the drivers of the large variability in the electrodynamics of auroral arcs at fine scales. We used the Auroral Structure and Kinetics (ASK) instrument, located on Svalbard, in order to measure various electrodynamic properties of fine scale auroral arcs. We performed Spearman and Kendall statistical tests and found two significant correlations. The first is between the mean precipitation flux and the variability of flux, which we assume is because of the dynamic and bursty nature of the acceleration mechanism and its dependence on Alfvén waves. The second correlation is between the variability of the precipitating electron flux and the variability of the tangential component of the electric field close to the arc and perpendicular to the magnetic field. We propose that both variabilities occur because of the variability of the upward (field‐aligned) current sheet in and around the arc, which is dynamic and non‐uniform. The correlation between the two variabilities can therefore be explained by their common source. Key Points We report a statistical analysis of small scale electrodynamics, to better understand the drivers of small scale variability There is a significant correlation between average flux and variability of the flux in our events There is a significant correlation between variability of tangential component of the electric field and variability in flux We propose that variability of the dynamic non‐uniform field aligned current sheet would be a source of variability in both electric fields and in flux, causing them to be correlated