Articles | Volume 19, issue 10/12
Ann. Geophys., 19, 1273–1288, 2001

Special issue: CLUSTER

Ann. Geophys., 19, 1273–1288, 2001

  30 Sep 2001

30 Sep 2001

The Electron Drift Instrument on Cluster: overview of first results

G. Paschmann1, J. M. Quinn2, R. B. Torbert2, H. Vaith1, C. E. McIlwain3, G. Haerendel4, O. H. Bauer1, T. Bauer1, W. Baumjohann5, W. Fillius3, M. Förster1, S. Frey1, E. Georgescu1, S. S. Kerr3, C. A. Kletzing6, H. Matsui2, P. Puhl-Quinn1, and E. C. Whipple7 G. Paschmann et al.
  • 1Max-Planck-Institut für extraterrestrische Physik, 85748 Garching, Germany
  • 2University of New Hampshire, Durham, NH 03824, USA
  • 3University of California at San Diego, La Jolla, CA 92093, USA
  • 4International University Bremen, 28725 Bremen, Germany
  • 5Space Research Institute, 8042 Graz, Austria
  • 6University of Iowa, Iowa City, IA 52242, USA
  • 7University of Washington, Seattle, WA 98195, USA

Abstract. EDI measures the drift velocity of artificially injected electron beams. From this drift velocity, the perpendicular electric field and the local magnetic field gradients can be deduced when employing different electron energies. The technique requires the injection of two electron beams at right angles to the magnetic field and the search for those directions within the plane that return the beams to their associated detectors after one or more gyrations. The drift velocity is then derived from the directions of the two beams and/or from the difference in their times-of-flight, measured via amplitude-modulation and coding of the emitted electron beams and correlation with the signal from the returning electrons. After careful adjustment of the control parameters, the beam recognition algorithms, and the onboard magnetometer calibrations during the commissioning phase, EDI is providing excellent data over a wide range of conditions. In this paper, we present first results in a variety of regions ranging from the polar cap, across the magnetopause, and well into the magnetosheath.

Key words. Electron drift velocity (electric fields; plasma convection; instruments and techniques)

Special issue