Relativistic Laser-Matter Interaction and Relativistic Laboratory Astrophysics

The paper is devoted to the prospects of using the laser radiation interaction with plasmas in the laboratory relativistic astrophysics context. We discuss the dimensionless parameters characterizing the processes in the laser and astrophysical plasmas and emphasize a similarity between the laser and astrophysical plasmas in the ultrarelativistic energy limit. In particular, we address basic mechanisms of the charged particle acceleration, the collisionless shock wave and magnetic reconnection and vortex dynamics properties relevant to the problem of ultrarelativistic particle acceleration.Comment: 58 pages, 19 figure

Relations between Russia and South Korea in the Arctic Region: Current Situation and Perspectives

The authors present a brief overview and motives for expanding of the Korean presence in the Arctic. The bilateral interaction between Russia and Korea in the economic and political sphere is analyzed. The authors conclude with highlighting topical issues of Russo-Korean relations in the Arctic and propose some ideas for the development of relations between the two countries

Homophily Evolution in Online Networks: Who Is a Good Friend and When?

Homophily is considered by network scientists as one of the major mechanisms of social network formation. However, the role of dynamic homophily in the network growth process has not been investigated in detail yet. In this paper, we estimate the role of homophily by various attributes at different stages of online network formation process. We consider the process of online friendship formation in the Vkontakte social networking site among first-year students at a Russian university. We reveal that at the beginning of the network formation a similarity in gender and score in entrance exams plays the key role, while by the end of network establishment period the role of the same group affiliation becomes more important. We explain the results with the tendency of students to follow different strategies to control the information flow in their social environment