Institution: | 1.Blekinge Institute of Technology, 371 79, Karlskrona, Sweden ;2.Department of Physics, Moscow State University, Moscow, Russia, 119991 ;3.Nizhni Novgorod State University, Nizhni Novgorod, Russia ;4.Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow, Russia ;5.Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia ; |