An Investigation of the Spatial Scales of the Change in Electric Field Observed at the Front of a Quasi-perpendicular Shock.

Using data from the Cluster EFW instrument it is shown that there is a general increase in the level of the electric field observed as the shock is crossed and the extent of this region appears to be larger than that of the magnetic ramp. However, within this region, short scale spike-like features in the electric field are commonly observed. The scale size of these features is determined and their relationship to various upstream parameters investigated.