Electric field scales at quasi-perpendicular shocks
- 1Department of Automatic Control and Systems Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
- 2Swedish Institute of Space Physics, Uppsala Division, Box 537, SE-751 21 Uppsala, Sweden
- 3Blackett Laboratory, ICSTM, Prince Consort Road, London. UK
Abstract. This paper investigates the short scale structures that are observed in the electric field during crossings of the quasi-perpendicular bow shock using data from the Cluster satellites. These structures exhibit large amplitudes, as high as 70 m Vm-1 and so make a significant contribution to the overall change in potential at the shock front. It is shown that the scale size of these short-lived electric field structures is of the order of a few c/ωpe. The relationships between the scale size and the upstream Mach number and θBn are studied. It is found that the scale size of these structures decreases with increasing plasma β and as θBn→90°. The amplitude of the spikes remains fairly constant with increasing Ma and appears to increase as θBn→90°.