D.A. Istomin – Post-graduate Student, Perm National Research Polytechnic University 

E-mail: dai@pstu.ru

M.B. Gitman – Dr.Sc. (Phys.-Math.), Professor, Perm National Research Polytechnic University

E-mail: gmb@pstu.ru

V.A. Trefilov – Dr.Sc. (Eng.), Professor, Perm National Research Polytechnic University

E-email: bg@pstu.ru