Dynamic Screening and Thermonuclear Reaction Rates

We show that there are no dynamic screening corrections to the Salpeter's enhancement factor in the weak-screening limit.Comment: 7 pages LaTex, no figures, Submitted to Ap

Toroidal equilibria in spherical coordinates

The standard Grad-Shafranov equation for axisymmetric toroidal plasma equilibrium is customary expressed in cylindrical coordinates with toroidal contours, and through which benchmark equilibria are solved. An alternative approach to cast the Grad-Shafranov equation in spherical coordinates is presented. This equation, in spherical coordinates, is examined for toroidal solutions to describe low $\beta$ Solovev and high $\beta$ plasma equilibria in terms of elementary functions

Effects of Rotation and Relativistic Charge Flow on Pulsar Magnetospheric Structure

We propose an analytical 3-D model of the open field-line region of a neutron star (NS) magnetosphere. We construct an explicit analytic solution for arbitrary obliquity (angle between the rotation and magnetic axes) incorporating the effects of magnetospheric rotation, relativistic flow of charges (e.g. primary electron beam) along the open field lines, and E X B drift of these charges. Our solution employs the space-charge-limited longitudinal current calculated in the electrodynamic model of Muslimov & Tsygan (1992) and is valid up to very high altitudes nearly approaching the light cylinder. We assume that in the innermost magnetosphere, the NS magnetic field can be well represented by a static magnetic dipole configuration. At high altitudes the open magnetic field lines significantly deviate from those of a static dipole and tend to focus into a cylindrical bundle, swept back in the direction opposite to the rotation, and also bent towards the rotational equator. We briefly discuss some implications of our study to spin-powered pulsars.Comment: 24 pages, 3 figures, accepted for publication in Ap

Shafranov's virial theorem and magnetic plasma confinement

Shafranov's virial theorem implies that nontrivial magnetohydrodynamical equilibrium configurations must be supported by externally supplied currents. Here we extend the virial theorem to field theory, where it relates to Derrick's scaling argument on soliton stability. We then employ virial arguments to investigate a realistic field theory model of a two-component plasma, and conclude that stable localized solitons can exist in the bulk of a finite density plasma. These solitons entail a nontrivial electric field which implies that purely magnetohydrodynamical arguments are insufficient for describing stable, nontrivial structures within the bulk of a plasma.Comment: 9 pages no figure

Career Self-Guidance as a Key Factor in the Development of High School Students’ Competitive Ability and Orientedness

Introduction. The article discusses the relationship between career self-guidance of high school students and their competitiveness. The authors highlight the indicators of career self-guidance and analyze their influence on the actualization of socially significant qualities, promoting the development of adolescent competitiveness. Influence of information technologies changes radically content and structure of professional activities. The ability to respond to the changes in the labor market and integrate into the relations while carrying out professional activity is essential for young people. The purpose of this article is to consider the specifics of career self-guidance of contemporary senior pupils and to analyze its influence on the competitive orientation of pupils. Materials and Methods. A questionnaire survey of high school students was selected for its reliability and validity in studying competitive skills. IBM SPSS Statistics 23 software was used to process and analyze the obtained data (N = 1 067 respondents). Results. The results reveal that the career self-guidance of high school students is a key factor in the process of formation of their competitive orientation. The main motives of future professional activity of senior students and the criteria of educational institution choice were defined. In addition, the key factors that influence the process of making decision of education continuing and their connection with competitive oriented pupils were considered. The indicators of career self-guidance process were revealed. Discussion and Conclusion. The research results may be useful for teachers and psychologists at high schools, for representatives who study competitive relations in educational sphere and for educators at vocational institutions and universities to develop career guidance strategies. These findings provide the following insights for future research: a comparative analysis of senior pupils’ career guidance measures` efficiency, conducted by different structures, the study of Internet technologies impact on career self-guidance and the study of atlases and new occupations list and their position in a future labor market

Current driven rotating kink mode in a plasma column with a non-line-tied free end

First experimental measurements are presented for the kink instability in a linear plasma column which is insulated from an axial boundary by finite sheath resistivity. Instability threshold below the classical Kruskal-Shafranov threshold, axially asymmetric mode structure and rotation are observed. These are accurately reproduced by a recent kink theory, which includes axial plasma flow and one end of the plasma column that is free to move due to a non-line-tied boundary condition.Comment: 4 pages, 6 figure