1. Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA, 143 avenue de Rangueil, 31400 Toulouse, France
2. Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
3. Clarendon
Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom