1. Blackett Laboratory, Imperial College, London SW7 2BW, United Kingdom
2. Sandia National Laboratories, PO Box 5800, Albuquerque, New Mexico 87185-1193, USA
3. Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1, Canada
4. Key Laboratory of Pulsed Power, Institute of Fluid Physics, CAE, Mianyang 621900, China
5. Department of Pulsed Plasma Diagnostics, Northwest Institute of Nuclear Technology, Xi'an 710024, China