Electric Field Measurements at the Magnetopause

During the first year of operation the Cluster satellites have traversed the magnetopause in a variety of local time sectors. High time resolution measurements of the spacecraft potential and the electric field from the Electric Field and Wave instrument are presented. The magnetopause location, orientation and velocity are determined from these measurements, and compared to magnetic field data from the Fluxgate Magnetometer instrument. The electric field is transformed to the magnetopause frame of reference and characteristics of the normal and tangential components are shown. The magneopause current as determined from the magnetic field is used together with the electric field to estimate the E.J power dissipation.