The Collisonal Tearing Mode Instability in a Quasi-stational Plasma

The behaviour of a small perturbation in the diffuse neutral sheet is analysed in a frame of MHD equations. It is shown that the normal magnetic component perpendicular to the current sheet does not contribute to the stability of the tearing instability in both the cases of high coductivity limit and low conductivity limit.The plasma flow expanding along the sheet can effectively stabilize the tearing instability.The nonlinear stage of this mode is estimated. It is shown that the secondary stationary flow with a hyperbolic pattern is structed.Tearing不安定は，天体プラズマ及び実験室プラズマでの応用と関連して，多くの研究がある。この不安定は，MHD的扱いのみならずCollisionlessプラズマでも起こる。又，この不安定は，太陽大気でのフレアー現象や，地球磁気圏での爆発的現象(substorm)と関連して，そして又，トカマクプラズマでのdisruptive不安定と関連しており，重要な不安定として研究されている。我々は，本稿で，MIlD領域でtearingmodeが安定化されないことを示す。論文の終わりで，tearing modeの非線形段階で現われる2次的な流れの効果についても述べる

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

Recent Advances in Understanding Particle Acceleration Processes in Solar Flares

We review basic theoretical concepts in particle acceleration, with particular emphasis on processes likely to occur in regions of magnetic reconnection. Several new developments are discussed, including detailed studies of reconnection in three-dimensional magnetic field configurations (e.g., current sheets, collapsing traps, separatrix regions) and stochastic acceleration in a turbulent environment. Fluid, test-particle, and particle-in-cell approaches are used and results compared. While these studies show considerable promise in accounting for the various observational manifestations of solar flares, they are limited by a number of factors, mostly relating to available computational power. Not the least of these issues is the need to explicitly incorporate the electrodynamic feedback of the accelerated particles themselves on the environment in which they are accelerated. A brief prognosis for future advancement is offered.Comment: This is a chapter in a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011

GPS positioning accuracy during the 2016 September and 2010 August campaigns at the SURA heater

We have conducted ionosphere heating experiments using HF radiation of SURA facility in August of 2010 and in September of 2016. We analyzed GPS positioning accuracy during the experiments. Positioning errors were estimated for 14 GPS receivers located at various distance, from just at the facility up to more than 1000 km from the facility. Data show that there were no noticeable positioning errors for both precise point positioning (PPP) and standard single-frequency modes