This paper presents the results of numerical simulation of plasma equilibrium and stability in the MEPHIST-0 tokamak with SIEMNED software and comparison of simulation results with experiments.The determined character...This paper presents the results of numerical simulation of plasma equilibrium and stability in the MEPHIST-0 tokamak with SIEMNED software and comparison of simulation results with experiments.The determined characteristics of the vacuum chamber show that it significantly affects the entire discharge.For various scenarios of the inductor operation,a comparison of experimental data and simulated currents and magnetic fields induced in the chamber was carried out.For steady-state tokamak operation,a numerical study of equilibrium plasma configurations was carried out depending on the currents in the poloidal magnetic field coils and plasma current.The vertical plasma instability was investigated.The limiting values of plasma ellipticity preventing the vertical plasma instability were numerically determined.Numerical simulations show that plasma equilibrium is supported by induced currents.It was shown numerically that magnetic configuration with‘zero of higher order’were obtained before the plasma shot,suggesting consistency between the simulation results and observations.展开更多
We present simulation results on evolution development of orbital motion of short-period comets with the revolution period not exceeding 6-7 years, namely comets 21P/Giacobini-Zinner, 26P/Grigg- Skjellerup and 7P/Pons...We present simulation results on evolution development of orbital motion of short-period comets with the revolution period not exceeding 6-7 years, namely comets 21P/Giacobini-Zinner, 26P/Grigg- Skjellerup and 7P/Pons-Winnecke. The calculations cover the range from the date of the object＇s discovery to 2100. Variations in the objects＇ orbital elements under the action of gravity disturbances, taking Earth＇s gravitational potential into account when the small body approaches, are analyzed. Corrected dates of peri- helion passages can be used for scheduling observations.展开更多
Primordial black holes （PBHs） are a profound signature of primordial cosmological structures and provide a theoretical tool to study nontrivial physics of the early Universe. The mechanisms of PBH formation are disc...Primordial black holes （PBHs） are a profound signature of primordial cosmological structures and provide a theoretical tool to study nontrivial physics of the early Universe. The mechanisms of PBH formation are discussed and observational constraints on the PBH spectrum, or effects of PBH evaporation, are shown to restrict a wide range of particle physics models, predicting an enhancement of the ultraviolet part of the spectrum of density perturbations, early dust-like stages, first order phase transitions and stages of superheavy metastable particle dominance in the early Universe. The mechanism of closed wall contraction can lead, in the inflationary Universe, to a new approach to galaxy formation, involving primordial clouds of massive BHs created around the intermediate mass or supermassive BH and playing the role of galactic seeds.展开更多
基金financial support of the Ministry of Education and Science of the Russian Federation as part of the program of the Mathematical Center for Fundamental and Applied Mathematics(No.075-15-2019-162)partly RFBR(No.20-07-00391)。
文摘This paper presents the results of numerical simulation of plasma equilibrium and stability in the MEPHIST-0 tokamak with SIEMNED software and comparison of simulation results with experiments.The determined characteristics of the vacuum chamber show that it significantly affects the entire discharge.For various scenarios of the inductor operation,a comparison of experimental data and simulated currents and magnetic fields induced in the chamber was carried out.For steady-state tokamak operation,a numerical study of equilibrium plasma configurations was carried out depending on the currents in the poloidal magnetic field coils and plasma current.The vertical plasma instability was investigated.The limiting values of plasma ellipticity preventing the vertical plasma instability were numerically determined.Numerical simulations show that plasma equilibrium is supported by induced currents.It was shown numerically that magnetic configuration with‘zero of higher order’were obtained before the plasma shot,suggesting consistency between the simulation results and observations.
文摘We present simulation results on evolution development of orbital motion of short-period comets with the revolution period not exceeding 6-7 years, namely comets 21P/Giacobini-Zinner, 26P/Grigg- Skjellerup and 7P/Pons-Winnecke. The calculations cover the range from the date of the object＇s discovery to 2100. Variations in the objects＇ orbital elements under the action of gravity disturbances, taking Earth＇s gravitational potential into account when the small body approaches, are analyzed. Corrected dates of peri- helion passages can be used for scheduling observations.
文摘Primordial black holes （PBHs） are a profound signature of primordial cosmological structures and provide a theoretical tool to study nontrivial physics of the early Universe. The mechanisms of PBH formation are discussed and observational constraints on the PBH spectrum, or effects of PBH evaporation, are shown to restrict a wide range of particle physics models, predicting an enhancement of the ultraviolet part of the spectrum of density perturbations, early dust-like stages, first order phase transitions and stages of superheavy metastable particle dominance in the early Universe. The mechanism of closed wall contraction can lead, in the inflationary Universe, to a new approach to galaxy formation, involving primordial clouds of massive BHs created around the intermediate mass or supermassive BH and playing the role of galactic seeds.
