1. Institute of Physics of the Earth, 10-1 B. Gruzinskaya, 123242 Moscow, Russia
2. Plasma Dynamics Group, Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield S13JD, United Kingdom
3. Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
4. The University of Texas at Austin, Austin, Texas 78712, USA
5. Plasma Dynamics Group, School of Mathematics and Statistics, University of Sheffield, Hicks Building, Sheffield S3 7RH, United Kingdom