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Szewczak K.,Central Laboratory for Radiological Protection | Jednorog S.,Poland Institute of Plasma Physics and Laser Microfusion
Physica Scripta | Year: 2014

The Institute of Plasma Physics and Laser Microfusion operates the biggest plasma focus device built so far in the world. It is identified as DPF-1000 U (Dense Plasma Focus Upgrade). The plasma produced by the described device constitutes a pulse of highly effective neutron source with the neutron yield ranging up to 1012 n per impulse. The precise composition of the stainless steel from which the vacuum chamber of the plasma focus device is made, was determined by neutron activation analysis. It was found that nuclear reactions that occur inside the stainless steel are mainly (n, γ), (n, p) and (n, α) reactions. Taking into consideration the neutron energy spectrum and the material composition, 63 nuclear reactions leading to vacuum chamber material activation were identified in total. It was observed that in the first hour after shut-down, the main activity comes from 59Fe and 59Ni isotopes. One year after the shut-down, the main contribution to the observed radioactivity of the experimental chamber material was related to the presence of 54Mn isotope, while after 10 years the only significant contribution to the activity will be made by molybdenum isotopes such as 93mMo and 99Mo. © 2014 The Royal Swedish Academy of Sciences.

Jablonski S.,Poland Institute of Plasma Physics and Laser Microfusion
Physica Scripta | Year: 2014

Results of a new relativistic two-dimensional particle-in-cell code for simulation of laser-driven ion acceleration are presented. It is shown that a complex electric field structure arose during the laser-target interaction as well as the evolution of the ion and electron concentration for the laser-induced cavity pressure acceleration scheme took place. During computation the influence of parameters such as target thickness and width, target starting position inside cavity and its atomic composition, as well as laser pulse length and beam width are examined. Values adopted for the calculation reflect the experimental conditions. © 2014 The Royal Swedish Academy of Sciences.

Kurzyna J.,Poland Institute of Plasma Physics and Laser Microfusion
Physica Scripta | Year: 2014

Although xenon has long remained the propellant of choice for Hall effect and ion thrusters, its very high price has motivated the investigation of other noble gases as cost-effective options. The development of a 500 W-class Hall thruster at the Institute of Plasma Physics and Laser Microfusion (IPPLM) aims at demonstrating the possibility of operating with krypton at efficiencies close to that obtained with xenon. However, krypton's lower ionization cross-sections need to be compensated by a significant increase of the mass flow rate in comparison with xenon. The subsequent increase of the thermal load has a large impact on the thermal design of the thruster. In order to assess the operating parameters and the thermal fluxes expected during krypton operation, an extensive parametric study of Krypton Large Impulse Thruster's performance was conducted with the one-dimensional time-dependent hydrodynamic HETMAn solver developed at IPPLM. Comparative computations for xenon and krypton confirm that high efficiencies with krypton are possible, with a predicted maximum efficiency only a few per cent below that of xenon, although at mass flow rates ∼50% higher. © 2014 The Royal Swedish Academy of Sciences.

Gribkov V.A.,Poland Institute of Plasma Physics and Laser Microfusion | Gribkov V.A.,RAS Institute of Metallurgy
Plasma Physics and Controlled Fusion | Year: 2015

The dense plasma focus (DPF) device represents a source of powerful streams of penetrating radiations (hot plasma, fast electron and ion beams, x-rays and neutrons) of ns-scale pulse durations. Power flux densities of the radiation types may reach in certain cases the values up to 1013W cm-2. They are widely used at present time in more than 30 labs in the world in the field of radiation material science. Areas of their implementations are testing of the materials perspective for use in modern fusion reactors (FR) of both types, modification of surface layers with an aim of improvements their properties, production of some nanostructures on their surface, and so on. To use a DPF correctly in these applications it is important to understand the mechanisms of generation of the above-mentioned radiations, their dynamics inside and outside of the pinch and processes of interaction of these streams with targets. In this paper, the most important issues on the above matter we discuss in relation to the cumulative hot plasma stream and the beam of fast ions with illustration of experimental results obtained at four DPF devices ranged in the limits of bank energies from 1 kJ to 1 MJ. Among them mechanisms of a jet formation, a current abruption phenomenon, a super-Alfven ion beam propagation inside and outside of DPF plasma, generation of secondary plasma and formation of shock waves in plasma and inside a solid-state target, etc. Nanosecond time-resolved techniques (electric probes, laser interferometry, frame self-luminescent imaging, x-ray/neutron probes, etc) give an opportunity to investigate the above-mentioned events and to observe the process of interaction of the radiation types with targets. After irradiation, we analyzed the specimens by contemporary instrumentation: optical and scanning electron microscopy, local x-ray spectral and structure analysis, atomic force microscopy, the portable x-ray diffractometer that combines x-ray single photon detection with high spectroscopic and angular resolutions, an x-ray microCT system with Cobra 7.4 and DIGIX CT software, microhardness measurements, etc. Some results in this area are presented. © 2015 IOP Publishing Ltd.

Barral S.,Poland Institute of Plasma Physics and Laser Microfusion | Peradzynski Z.,University of Warsaw
Physics of Plasmas | Year: 2010

The underlying mechanism of low-frequency oscillations in Hall accelerators is investigated theoretically. It is shown that relaxation oscillations arise from a competition between avalanche ionization and the advective transport of the working gas. The model derived recovers the slow progression and fast recession of the ionization front. Analytical approximations of the shape of current pulses and of the oscillation frequency are provided for the case of large amplitude oscillations. © 2010 American Institute of Physics.

Szewczak K.,Central Laboratory for Radiological Protection | Jednorog S.,Poland Institute of Plasma Physics and Laser Microfusion
Central European Journal of Physics | Year: 2014

Plasma research poses a radiation hazard. Due to the program of deuterium plasma research using the PF-1000 device, it is an intensive source of neutrons (up to 1011 n · pulse -1) with energy of 2,45 MeV and ionizing electromagnetic radiation with a broad energy spectrum. Both types of radiation are mostly emitted in ultra-short pulses (∼100 ns). The aim of this work was to test and calibrate the RSS-131 radiometer for its application in measurements of ultra-short electromagnetic radiation pulses with broad energy spectrum emitted during PF-1000 discharge. In addition, the results of raw measurements performed in the control room are presented. © 2014 Versita Warsaw and Springer-Verlag Wien.

Badziak J.,Poland Institute of Plasma Physics and Laser Microfusion
Bulletin of the Polish Academy of Sciences: Technical Sciences | Year: 2012

In 2009, in Lawrence Livermore National Laboratory, USA, National Ignition Facility (NIF) - the largest thermonuclear fusion device ever made was launched. Its main part is a multi-beam laser whose energy in nanosecond pulse exceeds 1MJ (106 J). Its task is to compress DT fuel to the density over a few thousand times higher than that of solid-state DT and heat it to 100 millions of K degrees. In this case, the process of fuel compression and heating is realized in an indirect way - laser radiation (in UV range) is converted in the so-called hohlraum (1 cm cylinder with a spherical DT pellet inside) into very intense soft X radiation symmetrically illuminating DT pellet. For the first time ever, the fusion device's energetic parameters are sufficient for the achieving the ignition and self-sustained burn of thermonuclear fuel on a scale allowing for the generation of energy far bigger than that delivered to the fuel. The main purpose of the current experimental campaign on NIF is bringing about, within the next two-three years, a controlled thermonuclear 'big bang' in which the fusion energy will exceed the energy delivered by the laser at least ten times. The expected 'big bang' would be the culmination of fifty years of international efforts aiming at demonstrating both physical and technical feasibility of generating, in a controlled way, the energy from nuclear fusion in inertial confined plasma and would pave the way for practical realization of the laser-driven thermonuclear reactor. This paper briefly reviews the basic current concepts of laser fusion and main problems and challenges facing the research community dealing with this field. In particular, the conventional, central hot spot ignition approach to laser fusion is discussed together with the more recent ones - fast ignition, shock ignition and impact ignition fusion. The research projects directed towards building an experimental laser-driven thermonuclear reactor are presented as well.

Ivanova-Stanik I.,Poland Institute of Plasma Physics and Laser Microfusion | Zagorski R.,Poland Institute of Plasma Physics and Laser Microfusion
Journal of Nuclear Materials | Year: 2015

Abstract This paper describes integrated numerical modeling applied to DEMO discharges with tungsten wall in slab geometry, rather than the full X-point geometry of the DEMO design, using the COREDIV code. Calculations are performed for inductive DEMO scenario with Ne, Ar and Ni seeding for different radial diffusion coefficients in the SOL region, and different pinch velocities for impurities in the core. Simulations show only for Ar and Ni, with high enough radial diffusion in the SOL, it is possible to achieve H-mode plasma operation (power to the SOL > L-H transition threshold power) with acceptable level of the power to the target plates. For neon seeding such regime of operation seems not to be possible. © 2014 Elsevier B.V.

Zielinska E.,Poland Institute of Plasma Physics and Laser Microfusion | Paduch M.,Poland Institute of Plasma Physics and Laser Microfusion | Scholz M.,Poland Institute of Plasma Physics and Laser Microfusion
Contributions to Plasma Physics | Year: 2011

Multiframe laser interferometer system for studies of rapidly varying processes in dense, high-temperature plasma in plasma-focus device is described. The setup of sixteen-frame interferometer contains the Mach-Zehnder system and the completely new, innovative beams separator which allows obtaining sixteen interferometric frames in one discharge. Each interferogram is recorded separately with the same linear size and quality. Delay from the first to the last frame is 220 ns. The result obtained using this system is given. It demonstrates its quality and suitability for investigations of dynamics of fast, irreproducible processes in PF-1000. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Danilko D.,Poland Institute of Plasma Physics and Laser Microfusion | Barral S.,QuinteScience
Physica Scripta | Year: 2015

In the presence of crossed electric and magnetic fields, charged particles in a plasma experience a drift in the E x B direction. Their transport in the direction parallel to the electric field is hindered by their gyration around magnetic field lines, giving rise to classical collision-driven transport, proportional to 1 B2. It is shown, however, that the fluid plasma description ignores a potentially large contribution to the cross-field mobility resulting from energy-position correlation of magnetized particles along their gyro-orbits. © 2015 The Royal Swedish Academy of Sciences.

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