Hannah Rogers, University of Edinburgh, Edinburgh, EH9, United Kingdom, Kathryn A Whaler, Univ Edinburgh, Edinburgh, United Kingdom and Ciaran Beggan, British Geological Survey, Edinburgh, United Kingdom

Beck E Strauss, National Institute of Standards and Technology Gaithersburg, Gaithersburg, MD, United States, Michael E Purucker, NASA Goddard Space Flight Center, Planetary Magnetospheres Laboratory, Greenbelt, MD, United States and David Sheppard, NASA Goddard Space Flight Center, Greenbelt, MD, United States

Yixiati Dilixiati, Eldar Baykiev and Joerg Ebbing, University of Kiel, Kiel, Germany

Alexey V Kuvshinov, Adriaan Visser and Alexander Grayver, ETH Swiss Federal Institute of Technology Zurich, Institute of Geophysics, Zurich, Switzerland

Sam Califf, University of Colorado, Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, Patrick Alken, University of Colorado Boulder, CIRES, Boulder, CO, United States and Arnaud Chulliat, National Geophysical Data Center, Boulder, CO, United States

Foteini Vervelidou, Massachusetts Institute of Technology, Cambridge, MA, United States, Vincent Lesur, Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, UMR 7154 CNRS/INSU, Paris, France, Benjamin P Weiss, MIT, Earth, Atmospheric and Planetary Sciences, Cambridge, MA, United States, Eduardo A. Lima, MIT-Earth & Planetary Sciences, Cambridge, MA, United States and France Lagroix, IPGP, Paris, France

Alain Plattner, University of Alabama, Geological Sciences, Tuscaloosa, AL, United States and Catherine Johnson, University of British Columbia, Vancouver, BC, Canada; Planetary Science Institute, Tucson, AZ, United States