Recent Achievements of Plasma Studies within PF-1000U Facility (original) (raw)
Related papers
Investigation of fusion-reaction protons from PF-discharges
Czechoslovak Journal of Physics, 2006
The paper describes results of the recent measurements of fusion-reaction protons, which were performed within the large PF-1000 facility operated at IPPLM in Warsaw. The main aim of those studies was to perform time-integrated measurements of fast (about 3-MeV) protons by means of ion-pinhole cameras, which were equipped with nuclear track detectors (of the PM-355 type) and appropriate absorption filters. To determine the angular distribution of fusion protons the use was made of seven miniature pinhole cameras placed at different angles to the PF-1000 axis. The irradiated and etched detectors were analyzed with an optical microscope. To gain more information about fusion processes occurring inside the high-temperature deuterium plasma, the results were compared with those provided by other diagnostics. The most important result is a comparison of the fusion-reaction protons characteristics with the results of neutron and hard X-ray measurements. Fusion-reaction neutron measurements, which were performed by means of a few scintillation-probes placed at different distances from the PF facility electrode outlet, delivered some complementary information.
Peculiar Features of Plasma-Focus Discharges Within PF360 Facility
Czechoslovak Journal of Physics, 2004
The paper reports on recent studies of plasma-focus (PF) discharge dynamics and fusion neutron emission, which were performed with the PF-360 device at the energy level of about 120 kJ and the maximum current of 1.85 MA. Using the high-speed multi-frame imaging system, the behavior of a current-sheath layer during the radial compression phase and of a plasma column during the pinch phase has been investigated. Dynamics of the pinch phase was studied in the visible radiation and soft X-rays simultaneously. Characteristics of the neutron emission from PF discharges, which were carried out with and without the use of planar D2O-ice target, were studied experimentally. In particular, the anisotropy coefficient, defined as a ratio of the fusion-neutron yield to that measured at 90° to the z-axis, i.e. Y n(θ)/Y n (90°), was investigated under different experimental conditions. Various structures of the time-resolved neutron signals were recorded and interpreted, e.g. as a result of a double pinch. Possible mechanisms of the fusion neutron production have also been discussed.
Measurements of ion micro-beams in RPI-type discharges and fusion protons in PF-1000 experiments
Physica Scripta, 2006
The paper reports on experimental investigation of micro-beams of fast ions emitted from high-current pulse discharges within the RPI-IBIS (Rod Plasma Injector) device in Swierk and the PF-1000 (Plasma-Focus) facility in Warsaw. Time-integrated ion measurements were performed with pinhole cameras equipped with solid-state nuclear track detectors (SSNTDs). Before expositions the SSNTDs were calibrated by means of mono-energetic ion beams and/or Thomson-type parabolas recorded on the detector samples. The ion-pinhole cameras were placed at different angles to the symmetry axes of the investigated facilities. In order to record fast (>3 MeV) protons, which originated from D-D nuclear fusion reactions in the PF-1000 facility, the SSNTDs were covered with appropriate Al filters. Time-integrated measurements of the fusion protons were performed for chosen series of PF discharges. The paper presents for the first time detailed maps of the fast proton fluxes, which makes it possible to draw conclusions regarding the spatial distribution of the fusion-proton sources.
Physics of Plasmas
Several series of high-current discharges were carried out within the PF-1000U facility at various gas conditions. The initial filling pressures were p 0 ¼ 1.2 hPa D 2 , 1.06 hPa D 2 þ 10% He, or 0.53 hPa D 2 þ 25% Ne. The discharges were performed with or without an additional gas puffing. In shots with the puffing, 1 cm 3 of gas (or mixture), compressed to the pressure of (0.13-0.20) MPa, was injected 1.5 ms before the discharge initiation. Pure D 2 , He, Ne, or a mixture of 50% He þ 50% Ne was used for puffing. The optical spectroscopic measurements were performed at a distance of 16 or 27 cm from the electrode outlets. Almost all discharges produced a dense plasmafocus (of about 10 cm in length) and a long plasma jet, which was observed for several ls. The ambient plasma density at the investigated gas-conditions was about 10 16 cm À3 , but an admixture of 10% He or 25% Ne (added to the D 2-filling) induced an increase in this density by factor 1.8-2.5. In all the cases, the plasma jet density was above 10-times higher than that of ambient plasma. At the He-or Ne-puffing, this density reached (3.5-6) Â 10 17 cm À3. Electron temperatures in the plasma jet changed from about 5.0 to about 3 eV in 5-7 ls.
Journal of Physics D-applied Physics, 2007
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 the spatial cross correlations of different phenomena. Results of these experiments are in favour of a neutron emission model based on ion beam-plasma interaction with three important features: (1) the plasma target is hot and confined during a few 'inertial confinement times'; (2) the ions of the main part of the beam are magnetized and entrapped around the pinch plasma target for a period longer than the characteristic time of the plasma inductive storage system and (3) ion-ion collisions (both fusion collisions, due to head-on impacts and Coulomb collisions) are responsible for neutron emission. Analysis has shown that one of the ways for achieving a future improvement in the neutron yield of the PF-1000 facility may by changing the geometry of the device. It may ensure an increase in both the discharge current and the initial working gas pressure, eventually resulting in the neutron yield boost.
Physica Scripta, 2006
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, CD 2 or metal wires, hydrogen or deuterium getters, special alloy targets, etc, is described. The paper presents results of different experiments oriented on the interaction of the pulsed plasma-ion streams with various material targets placed inside PF-360 device (at IPJ in Swierk) and PF-1000 facility (at IPPLM in Warsaw). Attention is paid to plasma-target interactions and influence of the material targets on emission characteristics of the PF-type discharges. The diagnostics includes current and voltage measurements, optical photography and spectroscopy, x-ray emission observations and fast-neutron measurements (from deuterium discharges). Particular attention is paid to time-resolved spectroscopic studies. The use of pulsed ion-and plasma-streams for modifications of different materials, e.g. those of particular interest for the construction of nuclear fusion reactors, is described.
Studies of plasma interactions with tungsten targets in PF-1000U facility
Nukleonika, 2016
This paper presents results of experimental studies of tungsten samples of 99.95% purity, which were irradiated by intense plasma-ion streams. The behaviour of tungsten, and particularly its structural change induced by high plasma loads, is of great importance for fusion technology. The reported measurements were performed within a modified PF-1000U plasma-focus facility operated at the IFPiLM in Warsaw, Poland. The working gas was pure deuterium. In order to determine the main plasma parameters and to study the behaviour of impurities at different instants of the plasma discharge, the optical emission spectroscopy was used. The dependence of plasma parameters on the initial charging voltage (16, 19 and 21 kV) was studied. Detailed optical measurements were performed during interactions of a plasma stream with the tungsten samples placed at the z-axis of the facility, at a distance of 6 cm from the electrode outlets. The recorded spectra showed distinct WI and WII spectral lines. I...
Measurements of high energy electrons at PF-1000
Journal de Physique IV (Proceedings), 2006
The paper reports on measurements of pulsed high energy electrons formed by the PF 1000 device, operated at IPPLM in Warsaw, Poland. This plasma focus device is used as powerful pulse sources of particles and X-rays. When deuterium is used as a filling gas, fast neutrons originating from D-D fusion reactions can be also observed. To measure the electrons, X-rays and neutrons, we used different timeresolved diagnostics techniques, e.g. Cherenkov detectors, X-ray pinhole camera, visual quadro and streak cameras and different scintillation detectors for X-ray and neutrons. The correlations between obtained pulses and other investigated plasma -focus phenomena are discussed.
Progress in High-Temperature Plasma Research at NCBJ (Former Ipj) in Poland
2012
This invited lecture presents the most important results of theoretical and experimental studies of hightemperature plasma, which were performed at the NCBJ (former IPJ) in Otwock-Swierk, Poland, during recent two years. The research activity included: Studies of fast electrons and X-rays in Z-pinch and Tokamak devices; Research on applications of solid-state nuclear track detectors for detection of fast ions and neutrons emitted from plasma in experimental facilities of Z-pinch, Tokamak and ICF type; Investigations of high-temperature plasma streams and their interactions with solid targets; Ultra-high vacuum arc deposition of thin metallic films; Selected studies on plasma engineering of solid surfaces. The formation of the NCBJ (on Sept. 1, 2011) and its successive reorganization (on Jan. 1, 2012) led to the separation of the Division of Plasma Studies (TJ5) which is concentrated on high-temperature plasmas within frames of domestic and international research programs. PACS: 52.5...
Plasma Focus Fusion Research in Singapore
Protons from two fusion reactions -D( 3 He,p) 4 He and D(d,p) 3 H -were measured for a small plasma focus device operated with a 3 He-D 2 gas mixture. A pinhole camera on the forward plasma focus axis imaged the emission zones of protons for both reactions. For the sake of comparison, analogous experiments were performed with a 4 He-D 2 gas mixture and pure D 2 gas. For the 3 He-D 2 and 4 He-D 2 gas mixtures the He to D 2 partial pressures were in the ratio of 2:1, corresponding to an atomic number ratio of 1:1. For the 3 He-D 2 gas mixture two groups of protons with energies of approximately 3 and 15 MeV were observed: products of the D(d,p) 3 H and D( 3 He,p) 4 He reactions, respectively. These protons were recorded simultaneously using a doublelayer arrangement of CR-39 polymer nuclear track detectors. For the 4 He-D 2 and D 2 gases, D(d,p) 3 H protons were measured using a single layer of CR-39. For the 3 He-D 2 gas mixture it was found that the D( 3 He,p) 4 He and D(d,p) 3 H proton yields were of similar magnitude, but their angular distributions were very different. Monte Carlo simulations were performed to interpret the measured angular distributions in terms of an isotropic pinchsource contribution and an anisotropic beam-target source over an extended conical volume. It was found that both the D( 3 He,p) 4 He and D(d,p) 3 H fusion yields are produced predominantly by the beam-target mechanism: any contribution from thermonuclear fusion being less than 10% of the total yield. For the case of pure D 2 gas, a magnetic spectrometer was employed to measure the energy spectra of forward-axially-directed deuterons emitted from the plasma focus pinch. Spectra for a large number of plasma focus shots were measured, enabling the correlation between the intensity of the deuteron beam and the associated neutron yield to be studied at each of three working gas pressures. A clear positive correlation was observed at each gas pressure, further supporting the conclusion that the beam-target fusion mechanism is dominant for this small plasma focus device.