Vladimir Gribkov

Russian Academy of Sciences | RAS · A. A. Baikov Institute of Metallurgy and Materials Science (IMET)

The changes of the structure and properties of a dual phase tungsten (W) alloy (with either 3 % or 5 % of an added mixture of Fe and Ni) are investigated after irradiation with powerful deuterium plasma pulses. The interplay of very powerful plasma pulses, comparable with the off-normal events of ITER or plasma pulses with heat flux factor values c...

Armour materials in fusion devices, especially in the region of divertor, are exposed to a continuous heat and particle load. In addition, several off-normal events can reach the material during a work session. Calculations show that the effects of plasma and heat during such events can lead to cracking, erosion and detachment of the armour materia...

In this study, morphological, microstructural and phase changes of four types of tungsten materials after exposure to dense deuterium plasma were examined. The microstructures of the prepared materials mutually differ by the porosity, grain size and phase content. It was found that inherent porosity of sintered materials leads to a specific mechani...

Progress in the field of nuclear fusion requires the development of a new generation of tungsten materials that are expected to meet specific property, lifetime and safety requirements. Pursuing this goal, the new materials must be properly tested in a wide range of conditions including cases where material is brought to the molten stage, such as w...

The influence of extreme heat loads, as produced by a multiple pulses of non-homogeneous flow of slow plasma (0.1–1 keV) and fast ions (100 keV), on double-forged tungsten (DFW) was investigated. For generation of deuterium plasma and fast deuterons, plasma-focus devices PF-12 and PF-1000 are used. Depending on devices and conditions, the power flu...

Today tungsten (W) is considered as the most perspective material for use as an element for the divertor system in construction of fusion facilities. Different investigations have shown that dispersed oxides cannot improve W properties significantly (e.g. creep strength, recrystallization, brittleness). Due to a number of disadvantages of pure W, t...

Samples of materials counted as perspective ones for use in the first-wall and construction elements in nuclear fusion reactors (FRs) with magnetic and inertial plasma confinement (W, Ti, Al, low-activated ferritic steel 'Eurofer' and some alloys) were irradiated in the dense plasma focus (DPF) device 'Bora' having a bank energy of ≤5 kJ. The devic...

In this note experimental studies of tungsten (W) samples irradiated by intense plasma-ion streams are reported. Measurements were performed using the modified plasma focus device DPF-1000U equipped with an axial gas-puffing system. The main diagnostic tool was a Mechelle®900 optical spectrometer. The electron density of a freely propagating plasma...

The paper presents some outcomes obtained during the year of 2013 of the activity in the frame of the International Atomic Energy Agency Co-ordinated research project »Investigations of Materials under High Repetition and Intense Fusion-Relevant Pulses». The main results are related to the effects created at the interaction of powerful pulses of di...

The paper presents a comparison of the results of numerical simulations of the shock wave (SW) produced inside a stainless steel plate by a powerful pulsed stream of fast ions generated in a dense plasma focus device with its experimental observations. A SW was detected for the first time in a materials science experiment directly by means of multi...

The effects of low and ultra-low doses of X-ray radiation and neutron fluxes produced by continuous-wave and pulsed sources of different nature and power on the activity of plant peroxidases and the bovine lung angiotensin-converting enzyme were studied. Certain ranges of doses (including ultra-low), the exposure to which under particular condition...

The double forged pure tungsten (W) samples (supplied by IAEA CRP from the FZJ team in Juelich, Germany) were irradiated in DPF (dense plasma focus) devices PF-12, ''Bora'' and PF-1000 by hot plasma and fast ion streams. We have used the following analytical methods: microscopy (optical and scanning electron), X-ray photoelectron spectroscopy, elec...

The double forged pure tungsten (W) samples (supplied by IAEA CRP from the FZJ team in Juelich, Germany) were irradiated in DPF (dense plasma focus) devices PF-12, “Bora” and PF-1000 by hot plasma and fast ion streams. We have used the following analytical methods: microscopy (optical and scanning electron), X-ray photoelectron spectroscopy, electr...

Experiments on the plasma focus device PF-12 have been carried out to investigate changes in the structure of the surface and bulk of tungsten and tungsten doped with 1% lanthanum oxide after repeated powerful deuterium plasma shots (8, 25 and 100). The surface morphology of the targets exposed to plasma streams is analyzed by electron and optical...

Scanning electron microscopy, X-ray electron probe analysis, and X-ray phase analysis are used to investigate the surface structure of W-1% La2O3 alloy after irradiation with submicrosecond pulses of deuterium ions and high-temperature deuterium plasma in a Plasma Focus installation for simulation of a plasma disruption in the ITER tokamak. It is e...

This paper reports on studies of the plasma-irradiation resistance of silicon carbide (SiC). The SiC target was placed on the symmetry axis of a PF-1000 facility, at a distance of 9 cm from the inner electrode end. Pulsed plasma-ion streams were generated at p(0) = 1.3 hPa D-2 filling, and powered from a condenser bank charged to 380 kJ. Each plasm...

The paper presents results of experimental research on emission of the visible radiation (VR) from intense deuterium plasma streams propagating freely within a vacuum chamber or interacting with silicon-carbide (SiC) targets. The investigated pulsed plasma streams were generated by high-current discharges realized within two facilities of the Plasm...

Erosion of divertor and first-wall armour material of ITER is still a problem not resolved. Tungsten as a candidate for the divertor material of ITER or other fusion devices is very brittle and has a high DBTT. The main damage in lower temperatures is a mesh of cracks. At higher temperatures sputters and splashes appear. It is suggested that additi...

Changes in the surface and structure of tungsten and tungsten doped with 1% lanthanum-oxide samples irradiated by powerful deuterium plasma shots are investigated. Comparative analysis of the samples microroughness, the damage factor estimated from SEM images, and the hardness of cross-sections has been carried out. It can be concluded that the dop...

This invited lecture presents the most important results of research on emission of the visible radiation (VR) from intense pulsed plasma-ion streams generated by high-current discharges within RPI- or PF-type experimental facilities. The optical emission spectroscopy measurements were performed during a free-propagation of such plasma-ion streams,...

Dynamics of the interaction of powerful streams of high-temperature plasma and fast ions generated in a device of the “Dense Plasma Focus” (DPF) type has been studied for a special case. In these experiments solid conductive targets with the shape of a plate and a tube, respectively, were placed normally and axially with respect to the Z axis of th...

The use of short and powerful neutron pulses for boron neutron capture therapy (BNCT) can potentially increase selectivity and reduce the total dose absorbed by the patient. The biological effects of radiation depend on the dose, the dose power and the spatial distribution of the microscopic energy deposition. A dense plasma focus (DPF) device emit...

Recent progress in the development of a Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects (explosives and other illicit materials) by means of measuring elastically and non-elastically scattered neutrons is presented. The method uses very bright neutron pulses having durations of the order of few n...

A novel technique with the potential of detecting hidden fissile materials is presented utilizing the interaction of a single powerful and nanosecond wide neutron pulse with matter. The experimental system is based on a Dense Plasma Focus (DPF) device as a neutron source generating pulses of almost mono-energetic 2.45 MeV and/or 14.0 MeV neutrons,...

We present results of experiments on the action of nanosecond pulsed beams of nitrogen ions and nitrogen plasma on specimens of Ti-4 Al-3 V (wt %) alloy that were obtained using a plasma focus device. Two regimes of material treatment were studied: a high-energy irradiation (with radiation power density of 108 W/cm2), where the surface layer is mel...

Experiments on the plasma focus devices PF12 and PF1000 have been carried out by using deuterium for investigating changes in the surface and structure of tungsten and tungsten doped with 1% lanthanum-oxide. The surfaces were analyzed and the damage factor of the irradiated samples was investigated by using electron microscopy. Also, microroughness...

The Workshop on Dense Magnetized Plasma and Plasma Diagnostics was held from 15 to 26 November 2010 at the Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy. It was attended by 60 participants, including 15 lecturers, 2 tutors and 37 trainees, representing 25 countries.

Two methods of temporal and spatial separation of the fluxes of hot plasma and fast ions in the Plasma Focus setup are experimentally investigated. In the first case, in a traditional geometry of the experiment, different distances from the focus to the target are used. Ion and plasma fluxes are generated at different instants, move with different...

Changes in the structure and phase composition of low-activated Cr-Mn austenite and 9Cr ferrite steels exposed to high-power nanosecond pulses of high-temperature nitrogen plasma and swift nitrogen ions (desk-size plasma focus devices, 106–109 W/cm2) are observed. Keywordshigh-temperature plasma–swift ions–nitrogen implantation–nitride phase

This paper reports on experiments undertaken to compare the radiation resistance of two types of ceramics, boron nitride (BN) and pure alumina (Al2O3), which are used in a TAEA antenna coil installed in the MAST spherical tokamak. Samples of the investigated materials (bulk BN and a 20 μm film of Al2O3 on Al substrate) were exposed on the axis of t...

Austenitic steel 10Cr12Mn14Ni4AlMo and Ti-4Al-3V alloy were irradiated with nanosecond pulsed nitrogen ion and plasma streams in plasma focus devices. The two different modes of the treatment were applied: high power density (≥ 10 8 W/cm 2) irradiation with melting of the surface layer and irradiation with power density ~ 10 7 W/cm 2 below the melt...

Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF)...

This paper gives results on the interaction of a chromium-manganese austenitic stainless steel and a pulsed high current deuterium beam. Features of damages, phase-structural transformations and chemical content changes were investigated. The interrelationship between the characteristics of the topographical surface structure and the number of puls...

A new-generation plasma-focus device is proposed to be used in a new inspection system for detection of hidden explosives and other illicit materials. Fast neutrons are produced in the D-D reaction (2.45 MeV) and are emitted during very short (∼ 10 ns) and intense pulses (up to 109 neutrons per pulse). The neutrons scattered by the investigated obj...

Recent progress in a single-pulse nanosecond technique of interrogation of unknown (hidden) objects by means of measuring of the elastically scattered neutrons is presented. The method uses very bright neutron pulses having duration of the order of 10 ns generated by Dense Plasma Focus (DPF) devices. Small size occupied by the neutron flash in spac...

Innovative technology of a plasma accelerator of the Dense Plasma Focus (DPF) type based on modern elements of high-current nanosecond electronics is presented. This technology ensures operation of the devices having capacitor bank energy 1 through 10 kJ with a high repetition rate (up to tens cps) and a long lifetime (on the level of 106 "shots")....

We present some results of our experiments with use of a number of plasma accelerators of the Dense Plasma Focus type, namely PF-5M (IMET, bank energy - 5 kJ), PF-6 (IPPLM, 7 kJ), and the largest in the world DPF facility operating with deuterium as a working gas PF-1000 (IPPLM, 1.2 MJ). We use this set of devices for application in the field of ra...

This paper presents a summary of the recent results reported on several topics on magnetic confinement, dense magnetized plasmas and materials studies. The main topics covered on magnetic confinement devices are configuration studies, diagnostics developments, alternative fuelling techniques, turbulence and transport studies, confinement experiment...

Dense Plasma Focus (DPF) devices' applications, which are intended to support the main‐stream large‐scale nuclear fusion programs (NFP) from one side (both in fundamental problems of Dense Magnetized Plasma physics and in its engineering issues) as well as elaborated for an immediate use in a number of fields from the other one, are describe...

Four small (in the energy range 2–7 kJ) dense plasma focus devices were elaborated and put into operation in the last several years: ING‐103, DPF‐10, PF‐5M, and DPF‐6. Each device has its own parameters (energy, current rise‐time and magnitude, pulse duration of ionizing radiation of different types, weight, etc.) and together with the specific di...

The paper reports on experimental studies of processes of the interaction of pulsed streams of fast deuterium ions (Ei~100 keV) and dense deuterium plasma (vpl>107 cm/s) with samples made of carbon and tungsten. Experiments were performed in the large PF-1000 plasma-focus facility with the charging energy of 481 kJ and with the pure deuterium filli...

The paper presents results of recent experimental studies within the PF-1000 plasma-focus facility [1], which were performed during the free propagation of pulsed plasma-ion streams inside the vacuum chamber, and during their interaction with different targets. Optical spectra were recorder by means of a Mechelle®900 spectrometer operated with some...

The Dense Plasma Focus (DPF) devices PF-1000, PF-6 and PF-5M working with different gases and in dissimilar irradiation modes were used to carry out experimental investigations of irradiation of a number of materials by powerful pulsed ion and high-temperature plasma streams. The materials under test were designed for application in structural and...

This paper describes investigations of neutrons produced by small plasma focus device PF-6 operating in the Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland. Main parameters of neutron radiation have been measured by scintillation probe, dI/dt probe and by activation technique. Simultaneously neutron transport calculations have bee...

The limits of applicability of double-beam interferometry in investigations of hightemperature plasma are considered. An analysis is made of the techniques for calculating interferograms of axisymmetric objects with steep density gradients by the Abel integral method. It is shown that the calculation methods used so far, based on the linear approxi...

The results are given of an experimental investigation of planar and quasicylindrical laser plasma cumulation. It is shown that when laser radiation is focused into a cone drilled in a solid target (and also in some cases of heating of a plane target), the dynamic heating is affected significantly by cumulative jets and parametric instability.

Electron and ion beam dynamics of the PF-1000 facility were investigated for the first time at its upper energy limit (ap1 MJ) in relation to neutron emission, the pinch's plasma ('target') characteristics and some other parameters with the help of a number of diagnostics with ns temporal resolution. Special attention was paid to the temporal and t...

This paper (paper I) presents the first part of results obtained with the PF-1000 facility for the first time at its upper energy limit (≈ 1 MJ). Special attention is paid here to plasma ('pinch') dynamics, which was investigated in relation to its electro-technical and radiation (especially neutron) characteristics with the help of a number of dia...

Electron and ion beam dynamics of the PF-1000 facility were investigated for the first time at its upper energy limit (≈1 MJ) in relation to neutron emission, the pinch's plasma ('target') characteristics and some other parameters with the help of a number of diagnostics with ns temporal resolution. Special attention was paid to the temporal and th...

Plasma dynamics and radiation characteristics of the PF‐1000 facility at its upper energy limit (≈ 1 MJ) were investigated by help of a number of diagnostics with ns temporal resolution. Special attention was paid to the temporal and spatial cross correlation between plasma, electron and ion beams dynamics as well as e/m radiation but in particul...

The paper presents results of recent experiments, as performed with the PF-1000 and PF-6 Plasma-Focus facilities, which were aimed at investigation of the correlation between processes of the irradiation of different materials of fusion devices and results of this irradiation. Among the irradiated samples there were pure tungsten, tantalum, copper,...

Dense Plasma Focus device is proposed for use as a neutron source to generate very powerful pulses of neutrons in the nanosecond (ns) range of its duration. Our devices PF‐6, recently put into operation at the Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland, and PF‐10 belonging to the Institute for Theoretical and Experimental Ph...

We report the observations of pinching in a miniature plasma focus (PF) (58—160 J) operated in repetitive mode using fast pseudospark switch (PSS). The size of the device, which includes the capacitor bank, PSS and the focus chamber, is of the order of 22 cm ×22 cm × 38 cm. Several diagnostic tools, the gated imager, streak camera, current and volt...

Experiments show that the performance of the plasma focus (PF) depends on several macroscopic parameters like the energy of the capacitor bank, current, voltage, electrodes dimension, and curvature of current sheath in the axial phase. Recent work (IEEE Trans. Plasma Sci., vol. 24, no. 3, pp. 1101-1105, 1996) shows that overriding the dependence of...

Common research topics that are being studied in small, medium and large devices such as H-mode like or improved confinement, turbulence and transport are reported. These included modelling and diagnostic developments for edge and core, to characterize plasma density, temperature, electric potential, plasma flows, turbulence scale, etc. Innovative...

A source of soft X-ray emission (9–14Å) based on the miniature 15kJ plasma focus was developed and tested. The X-ray emission was channelled along the chamber axis through an opening in the inner electrode (anode). A regime with a mean output of more than 100 J per discharge was found. At a discharge current of 280kA and repetition rate of 3.5Hz ac...

This paper concerns various applications of powerful ion- and plasma-streams generated by high-current pulse discharges realized within different plasma-focus (PF) facilities. General characteristics of the emitted plasma-ion streams are summarized. The possibility of application of special arrangements, e.g. cryogenic targets, CD2 or metal wires,...

The paper presents characteristics of synthetic sapphire, natural quartz and topaz after their irradiation in the RPI-IBIS facility by microsecond-pulses of hydrogen plasma with ions of energies up to tens keV. The optical reflection (measured in the 200-900 nm range) was compared with data obtained from optical and atomic force microscopy, and fro...

Plasma-focus device is intended to be used in a single shot inspection system for a detection of hidden explosives. Fast neutrons emitted during a short, intense pulse are scattered by the investigated object. Unfolding of the elemental content of unknown bulk sample should be possible from the recorded energy spectrum of the scattered neutrons. Th...

Physics of high energy density (PHED) was developed during last four decades mainly in the context of interaction of high-power laser radiation with matter (see e.g. (1)). However absorption of this radiation in solid targets takes place at depths, which are much less than the working wavelength of the lasers due to a high-frequency skin-effect (by...

A review of results on the design and operation of the new efficient Dense Plasma Focus device PF-6 of medium size (transportable) having bank energy of ca. 7 kJ and possessing a long lifetime is presented. New data on the interaction of the pulsed fast ion beams and dense plasma streams generated at this apparatus with various materials are given....

A review of results and new data on the interaction of pulsed ion and dense plasma beams with metals in different Dense Plasma Focus (DPF) devices are presented. Different irradiation conditions with microsecond pulses of the power density in the range of 105-109 W/cm2 were applied. The most interesting thermal and radiation effects observed in bot...

A review of the results received in the course of fulfillment of the International Atomic Energy Agency Coordinated Research Project "Dense Magnetized Plasma" for the last 3 years is presented. Niche of the plasma type within the plasma physics field is outlined. Efforts of the CRP participants concentrated on design and operation of new Dense Magn...

A review of some experimental results obtained using the dense plasma focus (DPF) device PF-1000 is presented. The copper Kα1,2 radiation line generated by DPF in the case of device anode made of copper was the main object of this study. The predominance of this characteristic radiation over other kinds of radiation in the DPF X-ray spectrum is sho...

Several experiments are described that relate to the application of new regimes of radiation action on enzymes in vitro and some other materials. These regimes have recently come into practice due to the appearance of a new generation of devices with very short high-energy pulses of ionizing radiation. It is shown that the term "flash radiation bio...