1. Institute for Problems in Mechanics, Vernadskogo 101-1, Moscow 119526, Russia
2. Space Research Institute (IKI), Russian Academy of Sciences, Moscow, 117997, Russia
3. School of Mathematics and Statistics (SoMaS), The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK
4. Moscow Center for Fundamental and Applied Mathematics, Lomonosov Moscow State University, Moscow, 119991, Russia