Research of transportation efficiency of low-energy high-current electron beam in plasma channel in external magnetic field

Effective high current (5-20 kA) and low energy (tens of keV) electrons beam transportation is possible only with almost complete charging neutralization. It is also necessary to use quite high current neutralization for elimination beam self-pinching effect. The research is based on the self-consistent mathematical model that takes into account beam and plasma particles dynamic, current and charge neutralization of electron beam and examines the transportation of electron beam into a chamber with low-pressure plasma in magnetic field. A numerical study was conducted using particle in cell (PIC) method. The study was performed with various system parameters: rise time and magnitude of the beam current, gas pressure and plasma density and geometry of the system. Regularities of local virtual cathode field generated by the beam in the plasma channel, as well as ranges of parameters that let transportation beam with minimal losses, depending on the external magnetic field were determined through a series of numerical studies. In addition, the assessment of the impact of the plasma ion mobility during the transition period and during steady beam was performed

New Conformal Higher Spin Gravities in 3d3d

We propose a new class of conformal higher spin gravities in three dimensions, which extends the one by Pope and Townsend. The main new feature is that there are infinitely many examples of the new theories with a finite number of higher spin fields, much as in the massless case. The action has the Chern-Simons form for a higher spin extension of the conformal algebra. In general, the new theories contain Fradkin-Tseytlin fields with higher derivatives in the gauge transformations, which is reminiscent of partially-massless fields. A relation of the old and new theories to the parity anomaly is pointed out.Comment: 20 pages+refs; replaced with the journal versio

Opportunities Opened by Cooperation within the Eurasian Economic Union, Need to Actively Be Used, Including at the Regional Level

The article is devoted to prospects, which open for participants of the Eurasian Economic Union. The special attention is paid to cooperation at the regional level. The author analyzes economic, cultural, scientific relations of St. Petersburg with the State Parties of the Eurasian Economic Union

Type-B formal higher spin gravity

We propose non-linear equations for the formal Type-B Higher Spin Gravity that is dual to the free fermion or to the Gross-Neveu model, depending on the boundary conditions. The equations are directly obtained from the first principles: the gauge invariance of the CFT partition function on an arbitrary background for single-trace operators. We also get equations describing propagation of certain mixed-symmetry fields over higher spin flat backgrounds

A DISCRETE ELEMENT FORMALISM FOR MODELLING WEAR PARTICLE FORMATION IN CONTACT BETWEEN SLIDING METALS

The paper describes an advanced discrete-element based mechanical model, which allows modelling contact interaction of ductile materials with taking into account fracture and surface adhesion by the cold welding mechanism. The model describes these competitive processes from a unified standpoint and uses plastic work of deformation as a criterion of both local fracture and chemical bonding of surfaces in contact spots. Using this model, we carried out a preliminary study of the formation of wear particles and wedges during the friction of rough metal surfaces and the influence of the type of forming third body (interfacial) elements on the dynamics of the friction coefficient. The qualitative difference of friction dynamics in the areas of the contact zone characterized by different degrees of mechanical confinement is shown

Delirium in Children after Cardiac Surgery: Brain Resuscitation

This chapter presents the current data on delirium in children in the postoperative period with the correction of congenital heart defects. The analysis of the causes of delirium, according to the literature data, pathophysiology, clinical signs, and methods of diagnosis of postoperative delirium, is shown. In addition, methods for the prevention of delirium in children during cardiac surgery are presented

New Conformal Higher Spin Gravities in 3

peer reviewe

Matter-free higher spin gravities in 3D: Partially-massless fields and general structure

peer reviewe

Chiral criticality in doped Mn1−y_{1-y}Fey_ySi compounds

The critical spin fluctuations in doped compounds Mn$_{1-y}$Fe$_y$Si have been studied by means of ac-susceptibility measurements, polarized neutron small angle scattering and spin echo spectroscopy. It is shown that these compounds undergo the transition from the paramagnetic to helimagnetic phase through continuous, yet well distinguishable crossovers: (i) from paramagnetic to partially chiral, (ii) from partially chiral to highly chiral fluctuating state. The crossover points are identified on the basis of combined analysis of the temperature dependence of ac-susceptibility and polarized SANS data. The whole transition is marked by two inflection point of the temperature dependence of ac-susceptibility: the upper one corresponds to the crossover to partially chiral state at $T^*$, where the inverse correlation length $\kappa \approx 2 k$, the lower one corresponds to the transition to the spin helix structure. The intermediate crossover to the highly chiral phase is observed at the inflection point $T_k$ of the first derivative of ac-susceptibility, where $\kappa \approx k$. The temperature crossovers to the highly chiral fluctuating state is associated with the enhancing influence of the Dzyaloshinskii-Moria interaction close to $T_c$.Comment: 5 pages, 5 figures, 1 table, 13 cite