Troitsk Institute for Innovation and Fusion Research

Two-photon laser generation of exciton states in krypton cryocrystals as a method for excitation of an anomalous low-energy isomeric nuclear state in the Thorium-229 isotope, Borisyuk P.V., Myzin D.A., Gubskiy K.L., Didenko N.V., Korneev P.A., Kuznetsov A.P., Lebedinskii Yu.Yu., Nauryzbaev Ja.M., Popruzhenko S.V., Chubunova E.V., Shilov V.A., Tkalya E.V.

The paper examines factors influencing tritium handling in a tokamak with reactor technologies (TRT) and in its operational support systems. It identifies the problems that should be taken into account when designing the tritium technological complex of the TRT facility and its implementation is formulated in the existing buildings on the site of JSC SSC RF TRINITI. The operating principle of the tritium complex and the operating characteristics of the devices that ensure the collection, processing, and storage of tritium for thermonuclear fusion experiments are described.

The object of our study is a barrier discharge in a capillary quartz tube blown with argon flow at atmospheric pressure. The discharge was powered by sinusoidal voltage with a frequency of 125 kHz. We present the experimental results on time-spatial behavior of the plasma structures arising both inside a discharge tube and in the plasma jet. Using high-speed and multi-frame Intensified Charge Coupled Device (ICCD) imaging of the discharge, it was revealed that the formation of the diffuse and constricted plasma structures inside the discharge zone and in plasma jet. The constricted plasma structures have a “memory,” that is, they save their spatial shape in time but not more than 100–150 μs. This time interval is much shorter compared to the time spent by gas flow to pass the discharge zone inside the tube. The plasma structures were formed jointly by the diffuse and constricted surface ionization waves arising and disappearing each half-cycle of the applied voltage. The revealed diffuse surface ionization waves are identical to well-known ionization waves (in fact, surface ionization waves) propagating inside a long capillary tube, but constricted surface ionization waves are similar to those propagating along a flat dielectric barrier in a pin-to-plane surface barrier discharge. Additionally, it was shown mathematically that the linear diffusion equation for plasma potential can be applied to describe the propagation of the diffuse surface ionization wave.

Experimental and numerical studies of the features of the spatial distribution of plasma parameters in a discharge not limited by walls were performed. A discharge supported by a hollow cathode in helium at low pressure was ignited in a chamber with dimensions much larger than the dimensions of the discharge system, and the distance between the cathode and the mesh anode significantly exceeded the height of the anode. Two-dimensional spatial distributions of the plasma potential, electron concentration, and average electron energy were measured by the Langmuir probe method. It was shown that, under experimental conditions, the region of plasma existence significantly exceeds the region limited by the aperture of the discharge system, and a significant concentration of electrons is observed in the region behind the anode. Numerical studies within the framework of 2D Monte Carlo simulation were performed. Electrons were launched from the open side of the cathode, and their motion in a given electric field was simulated. In the measurement region, the electric field was calculated from the measured values of the plasma potential and, outside this region, model assumptions about the field magnitude were used. The calculated and measured spatial distributions of electron concentration and their average energy were compared.

The article provides an overview of physical ideas, analytical and computational algorithms, specific practical applications that make up G. D. Malyuzhinets’ contribution to the development of the parabolic equation method: the principle of transversal diffusion; parabolic wave equation in ray coordinates; solution by the finite-difference method; generalizations for problems in radiophysics, optics and geophysics. The presentation is illustrated by examples from the works of Malyuzhinets, his students and younger colleagues.