Results from experiments on the radial distribution of the magnetic fields in axial plasma flows formed during the compression of a plasma–current sheath carried out at the KPF-4-PHOENIX plasmafocus installation are presented. The plasma flows were generated in a discharge with stationary filling of the chamber with a working gas of argon or hydrogen, and also with a pulsed injection of argon. Analysis of the radial profiles of the magnetic field distribution and their time variations are used to localize regions of trappedmagnetic field, as well as regions where a return current flows at the periphery of the plasma flow. It is shown that the transverse (radial) size of the plasma flow depends on the density of the ambient medium (background gas) through which it propagates. These experiments were carried out in the framework of a project on laboratory simulations of non-relativistic jets from young stars.

The results of experiments aimed at investigating axial plasma flows forming during the compression of a current–plasma sheath are presented. These experiments were carried out at the KPF-4-PHOENIX plasma-focus installation, as part of a program of laboratory simulations of astrophysical jets. The plasma flows were generated in a discharge when the chamber was filled with the working gas (argon) at initial pressures of 0.5–2 Torr. Experimental data obtained using a magnetic probe and optical diagnostics are compared. The data obtained can be used to determine the location of trapped magnetic field relative to regions of intense optical glow in the plasma flow.

Experiments with electric explosion of tungsten wires are described. These are intended to check the results of G.L. Wendt and C.E. Irion’s experiments published in 1922. The historical and theoretical background of this study are described in detail. The gas phase formed in the chamber after the electric explosion was carefully studied in the experiments. The results of the study do not contradict with the results of the Wendt and Irion experiments. c ⃝ 2017 ISCMNS. All rights reserved. ISSN 2227-3123

Results are presented from experimental studies of the plasma flows generated in the KPF-4 Phoenix Mather-type plasma focus device (Sukhum Physical Technical Institute). In order to study how the formation and dynamics of the plasma flow depend on the initial distribution of the working gas, a system of pulsed gas puffing into the discharge volume was developed. The system allows one to create profiled gas distributions, including those with a reduced gas density in the region of plasma flow propagation. Results of measurements of the magnetic field, flow profile, and flow deceleration dynamics at different initial distributions of the gas pressure are presented.

Представлены результаты измерений магнитных полей в области пинчевания плазмы при сжатии токово-плазменной оболочки в разряде в дейтерии на установке плазменный фокус КПФ-4-ФЕНИКС. Исследована при помощи магнитозондовой методики “тонкая” структура токонесущей плазменной оболочки (ударная волна – магнитный поршень) и ее изменение по мере сжатия плазмы к оси установки. Показано, что эффективность транспортировки тока плазменной оболочкой в приосевую область установки не превышает 65% от полного разрядного тока. Интегральный выход нейтронов Yn хорошо описывается зависимостью Yn (1.5-3)?1010I , где Ip – ток пинча внутри области r 22 мм.

Results are presented from magnetic probe measurements in the pinching region formed during the compression of the plasma current sheath (PCS) in a discharge in deuterium at the KPF-4-Phoenix plasma focus facility. The fine structure (shock front-magnetic piston) of the PCS and its time evolution in the course of plasma compression toward the facility axis was studied by means of magnetic probes. It is shown that the fraction of the current transported into the axial region by the PCS does not exceed 65% of the total discharge current. The integral neutron yield Y n is well described by the formula Y n ≈ (1.5–3) × 10 10 I p 4 , where I p (in MA) is the pinch current flowing in the region r ≤ 22 mm.

The engineering characteristics of the KPF-4 Phoenix megajoule Mather-type plasma focus facility constructed at the Sukhumi Physicotechnical Institute are described. Results from preliminary studies of the plasma dynamics at a capacitive-storage energy of up to 700 kJ are discussed. Future experiments in KPF-4 will be oriented at technological applications and will complement the studies carried out in the 2.8-MJ Filippovtype PF-3 plasma focus facility at the Nuclear Fusion Institute of the Russian Research Centre Kurchatov Institute.

Приведены технические характеристики сооруженной в Сухумском физико-техническом институте крупной плазмофокусной установки КПФ-4 (“Феникс”) мегаджоулевого уровня с разрядным устройством мэйзеровского типа. Обсуждаются результаты предварительных исследований динамики плазмы, проведенных при энергосодержании емкостного накопителя до 700 кДж. Планируемые на КПФ-4 исследования ориентированы на технологические применения и дополнят ведущиеся в ИЯС РНЦ “КИ” работы на ПФ-3 (2.8 МДж) с разрядным устройством филипповского типа.