The 2013 Hannes Alfvén Medal is awarded to Göran Marklund for his outstanding contributions in auroral physics, especially his discovery of downward directed magnetic-field aligned electric fields, an essential feature of the auroral circuit, and their association with black aurora.
Göran Marklund received his PhD in plasma physics from the Royal Institute of Technology in Stockholm, Sweden in 1983. His thesis was an important contribution to the classification of aural arcs based on direct measurements of electric fields in the auroral plasma. As a co-worker and later successor of Ulf Fahleson and Lars Block, Göran Marklund specialised in theory and measurements of auroral electric fields by means of rockets and satellites, using the double-probe technique. This was very much in the spirit of Hannes Alfvén, who frequently emphasised the crucial importance of direct measurements of electric fields in space as a check on theory and simulation.
As leader of the space research programme of the Division of Space and Plasma Physics of the Royal Institute of Technology, Göran Marklund has greatly contributed to the success of this research. He has been PI of the electric field experiments on the satellites Viking and Freja, has been involved in a number of other missions, and is author in more than a hundred refereed publications. Amongst his achievements is the discovery of the existence of downward directed magnetic-field aligned electric fields in the auroral return current region. He has pioneered the experimental study of the temporal evolution of these electric fields and their role in the auroral circuit, as well as their relation to black aurora. Further, he established experimentally that magnetic-field-aligned electric fields are ubiquitous in magnetised space plasmas, existing regardless of current direction, electric resistance, and magnetic field divergence.
In summary, Marklund has in a substantial way paved the way for the understanding of plasma processes in the solar system and other cosmical plasma environments, which makes him a very worthy recipient of the Alfvén Medal.