In the plasma focus chamber of the PF-MOL facility, a pulse valve allows an inhomogeneous density of the working gas to be obtained. In the combined mode of operation (stationary filling and additional injection), it is possible to use different gases together in one run. The facility has a capacitive source with a maximum current of 750 kA. The chamber houses a system of magnetic probes. At currents of 700 kA in the normal mode of stationary filling with deuterium, the neutron yield Yn is (4–5) × 109 per pulse. The maximum yield Yn = 1.2 × 1010 was obtained with the additional pulsed deuterium resupply of the area of current sheath focusing. Experiments have been carried out with a helium current sheath that compresses the injected deuterium. At a current of 530 kA, the yield Yn 2 × 109 was reproducibly recorded. Tests have been carried out that indicate the absence of a helium impurity in the deuterium pinch plasma.

The problem of building a fertility management system for reclaimed lands is considered and it is stated that a possible cause of failures in increasing fertility is not only the incomplete formulation of the concept of fertility in the laws, but also the lack of effective tools for assessing organic matter in the soil. Possibilities and some experiments on the use of an X-ray microscope to assess soil organic matter are being considered. Methodological issues of preparing samples for research are discussed, and the possibility of determining the biomass of the soil biotic community based on the results of fluoroscopy of the soil sample is established. Analysis of X-ray images of peat soils showed the possibility of determining in the sample organic matter (48%), water (30%), air (20%), mineral particles less than 2%. It became possible to see and analyze the volume of the rhizosphere of the root of the plant, the space in which the main processes of preparing the nutrient «substrate» for the plant with soil biota take place. Given that the X-ray radiation of this microscope does not damage living tissues, presumably, it is possible to observe the dynamics of changes in the rhizosphere, thus visualizing the processes of change in actual fertility over time. The prospects for using this methodology for reclamation studies related to the management of the fertility of reclaimed lands within the framework of the concept of development of accurate reclamation regulation of environmental factors, the scope of which includes not only the plant, but also the soil biota, were discussed. It is assumed that the considered methodology can be used to manage (minimize) the «carbon footprint»” in land reclamation.

— In electromagnetic generators of the terawatt range with current pulse of 1–30 MA, electric explosion of the surface of current-carrying electrodes takes place. One of the options for protecting the electrodes is covering the current-carrying surface with different materials. In this work, we present experimental data and results of numerical simulations of the processes that take place in a thick-walled heterophase electrode during the passage of current with a high linear density. The amplitude value of the linear current density in the simulations was of 2.8 MA/cm. The results of the simulations of the processes that occur in the electrodes during the passage of current with high linear density are in qualitative agreement with experimental data.

The formation of plasma on the surface of a current-carrying electrode of a high-current facility when a current flows through it with a linear density of up to 4 MA/cm and is coated with lead foil or ceramic is studied. The propagation velocity of a dense plasma from a stainless steel electrode is 2–10 km/s, and when the electrode is coated with lead, it is 1–6 km/s. In these experiments, there is no load typical for such facilities—a source of intense X-ray radiation. The plasma propagation from ceramic-coated electrodes starts 200 ns later than that for metal electrodes.

Thick-walled tubes were used as a model of line nodes that are subjected to the greatest dynamic and energy loads. The formation of plasma on the surface of lead-coated and ceramic-coated electrodes was studied using shadow frame and streak photography. The linear current density was of the order of 1-3 MA/cm with a rise time of 100 ns. It is necessary to underline that the experiment was conducted in the absence of a source of powerful x-ray radiation. Numerical calculations were performed to simulate the processes that occur in a thick-walled tube when a current with a high linear density is passed through it. The results of numerical modeling of parameter evolution in such a linear density of 3MA/cm for steel cylindrical conductor with diameter of d = 3mm and a wall thickness of 0.5 mm covered by lead foil is in good agreement with experiment.

Interaction of plasma flows and magnetic field with the formation of a shock wave in nested arrays V. V. Aleksandrov, A. V. Branitsky, A. S. Boldarev, V. A. Gasilov , E. V. Grabovskiy, A. N. Gritsuk, K. N. Mitrofanov, O. G. Olkhovskaya, P. V. Sasorov, A. O. Shishlov 1 Troitsk Institute for Innovation and Fusion Research, Troitsk, Moscow, Russia 2 Keldysh Institute of Applied Mathematics of the RAS, Moscow, Russia 3 National Research Nuclear University ‘MEPhI’, Moscow, Russia The results of plasma compression studies of nested wire and fiber arrays with current flowing through them are presented in this work. Experiments were made on the Angara-5-1 facility with current up to 4 MA. Current implosion of nested arrays represents a unique opportunity to simulate the interaction of a plasma flow with a magnetic field. Different plasma flow regimes in the space between the inner and outer arrays were obtained: subAlfven (Vr<VА), super-Alfven (Vr>VА) and a mode with the formation of a transition region—shock wave (SW)— between the arrays, depending on the radii ratio of the inner and outer arrays. The dependence of these flow regimes on the plasma production rate of the inner and outer arrays is shown. At certain parameters of nested arrays, a quasiclosed shell is formed in the azimuthal direction around the inner array. At the same time, the plasma of the outer array surrounds the inner and stabilizes its compression. The suppression of MRT instabilities during plasma compression of the inner array leads to the formation of a stable, compact Z-pinch and the generation of a short-time soft X-ray pulse.

The motion of the outer boundary of a quasi-spherical tungsten wire array at currents of 2−4 MA was studied experimentally. It is shown that the outer boundary shifts later than it is predicted by simulations by the heterogeneous array model. The instabilities developing at the boundary of the quasi-spherical array are similar to those occurring in a cylindrical array made of the same material. It is found that, in spite of the different time behaviors of the inductances during implosions of quasi-spherical and cylindrical arrays, the energies required to compress these arrays to ~0.4 of the initial radius differ insignificantly.

The output unit of the Angara-5-1 installation was upgraded in order to increase megabar pressure. Upgrading was carried out taking into account those fact that pressure was created using the magnetic field of the current flowing through the specimen. To increasing the power impulse acting on the flyer from the side of the magnetic field, variants of increasing the time duration of the magnetic field were considered by controlled current shorting (crowbar). In accordance with the mathematical simulation when extending the current pulse, it is possible to increase the flyer velocity by a factor of two.

Preliminary results are presented for the parameters of flyer used in experimental studies of material properties in the shock-wave compression of a sample by a magnetic field.

The high pressure created by magnetic field which was induced by the current flowing through the flyer allows one to reach the megabar pressures and to accelerate the flyers to high velocities. The effectiveness of the flyer acceleration was investigated on the Angara-5-1 installation at the linear current density up to 5 MA/cm.

Implosion of quasi-spherical wire arrays opens the possibility of more efficient use of the kinetic energy of the material being compressed to create a source of soft X-rays (SXR), compared to two-dimensional compression in the case of a cylindrical wire array. This is due to the contribution of the kinetic energy of the axial movement of the plasma into the internal energy of SXR source. The purpose of the experiments was to achieve three-dimensional synchronous compression of the plasma in the geometric center of a quasi-spherical array. For the optimal linear mass profile (m l (θ) = mfsinθ), it follows from the measured distribution of the azimuthal magnetic field that, in the stage of plasma production up to the SXR pulse, the plasma with the frozen-in magnetic field penetrates the array from the polar and equatorial regions almost synchronously. The size and shape of the X-ray radiation source in quasi-spherical current implosion were inferred from plasma emission spectrum measurement with spatial resolution and registration of framing X-ray images. Estimation of the radiation flux on the surface of such a source was received.

The experimental and numerical study of the evolution of the aluminum and steel flyers under flowing of submicrosecond megaampere current pulse with linear current density up to 5 MA/cm through it was carried out. It was obtained that during hundreds nanoseconds the substance of the aluminum flyer near its working surface is in the solid state, and the velocity of the surface can reached ~ 10 km/s.

Current leakages in the magnetically insulated transmission lines (MITL) impose restrictions on the transmission of electromagnetic pulses to the load in high-power electrophysical facilities. The multimodule Angara-5-1 facility with an output electric power of up to 6 TW is considered. In this work, the experimental and calculated profiles of leakage currents in two sections of the line are compared when the eight-module facility is loaded by a wire array. The azimuthal distribution of the current in the cylindrical section of the MITL is also considered.

Conditions for the propagation in soil of current pulses with an amplitude of up to 85 kA and temporal characteristics typical of a lightning stroke are studied with the help of a specially designed mobile test complex on the basis of a 4-MJ capacitive energy storage with an output voltage of up to 2 MV. In contrast to the conventional opinion that the ionization processes in highly conductive soils are weakly pronounced, a dramatic reduction in the grounding resistance at a resistivity of about 100 Ω m and currents above 10 kA was observed. A time interval in which the grounding resistance is determined by the skin effect in soil is revealed. It is shown that the grounding resistance continues to decrease behind the front of the current pulse due to the continuous growth of spark channels in soil. Time variations in the grounding resistance cannot be related to the formation of a continuous ionization zone near the grounding electrodes and are explained only by the simultaneous growth of several long spark channels extending from the grounding device.