Articles | Volume 35, issue 3
Ann. Geophys., 35, 645–657, 2017
Ann. Geophys., 35, 645–657, 2017

Regular paper 17 May 2017

Regular paper | 17 May 2017

Statistical survey of day-side magnetospheric current flow using Cluster observations: magnetopause

Evelyn Liebert, Christian Nabert, Christopher Perschke, Karl-Heinz Fornaçon, and Karl-Heinz Glassmeier Evelyn Liebert et al.
  • Institut für Geophysik und extraterrestrische Physik, Technische Universtität Braunschweig, Braunschweig, Germany

Abstract. We present a statistical survey of current structures observed by the Cluster spacecraft at high-latitude day-side magnetopause encounters in the close vicinity of the polar cusps. Making use of the curlometer technique and the fluxgate magnetometer data, we calculate the 3-D current densities and investigate the magnetopause current direction, location, and magnitude during varying solar wind conditions. We find that the orientation of the day-side current structures is in accordance with existing magnetopause current models. Based on the ambient plasma properties, we distinguish five different transition regions at the magnetopause surface and observe distinctive current properties for each region. Additionally, we find that the location of currents varies with respect to the onset of the changes in the plasma environment during magnetopause crossings.

Short summary
We present a statistical survey of current magnitudes, directions and locations at the high-latitude day-side magnetopause using Cluster's multi-spacecraft data. Our results show that the magnetopause current flow directions match expectations based on existing models and simulations. Current magnitudes are in correspondence with former studies. In addition, we observe a varying location of the currents with respect to changes in the ambient plasma properties.