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Wyświetlanie 1-8 z 8
Tytuł:
Interferometry of the plasma focus equipped with forehead cathode
Autorzy:
Kubeš, P.
Klír, D.
Rezac, K.
Paduch, M.
Pisarczyk, T.
Scholz, M.
Chodukowski, T.
Kalinowska, Z.
Hitschfel, J.
Kortanek, J.
Kravárik, J.
Ivanova-Stanik, I.
Bienkowska, B.
Karpinski, L.
Zielinska, E.
Sadowski, M. J.
Tomaszewski, K.
Powiązania:
https://bibliotekanauki.pl/articles/147512.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
interferometry
neutron diagnostics
plasma focus discharge
Opis:
The PF-1000 plasma-focus facility in Warsaw, equipped with Mather-type coaxial electrodes working with a deuterium filling, was modified by the addition of a cathode disk in front of the anode front-plate at a distance of 3 cm. The plasma was diagnosed with temporal resolved interferometry and neutron diagnostics. The modified electrode configuration showed an increase of the current in the pinch phase and a decrease of the total neutron yield. The lower total neutron yield is caused by a lower energy of deuterons producing the observed neutrons and by a decrease of the velocity of transformations of the structures in the pinch column.
Źródło:
Nukleonika; 2012, 57, 2; 189-192
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurements of fast electron beams and soft X-ray emission from plasma-focus experiments
Autorzy:
Surała, W.
Sadowski, M. J.
Kwiatkowski, R.
Jakubowski, L.
Żebrowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/147850.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron beams
X-ray emission
plasma focus
hot spots
Opis:
The paper reports results of the recent experimental studies of pulsed electron beams and soft X-rays in plasma-focus (PF) experiments carried out within a modifi ed PF-360U facility at the NCBJ, Poland. Particular attention was focused on time-resolved measurements of the fast electron beams by means of two different magnetic analyzers, which could record electrons of energy ranging from about 41 keV to about 715 keV in several (6 or 8) measuring channels. For discharges performed with the pure deuterium fi lling, many strong electron signals were recorded in all the measuring channels. Those signals were well correlated with the fi rst hard X-ray pulse detected by an external scintillation neutron-counter. In some of the analyzer channels, electron spikes (lasting about dozens of nanoseconds) and appearing in different instants after the current peculiarity (so-called current dip) were also recorded. For several discharges, fast ion beams, which were emitted along the z-axis and recorded with nuclear track detectors, were also investigated. Those measurements confi rmed a multibeam character of the ion emission. The time-integrated soft X-ray images, which were taken side-on by means of a pinhole camera and sensitive X-ray fi lms, showed the appearance of some fi lamentary structures and so-called hot spots. The application of small amounts of admixtures of different heavy noble gases, i.e. of argon (4.8% volumetric), krypton (1.6% volumetric), or xenon (0.8% volumetric), decreased intensity of the recorded electron beams, but increased intensity of the soft X-ray emission and showed more distinct and numerous hot spots. The recorded electron spikes have been explained as signals produced by quasi-mono-energetic microbeams emitted from tiny sources (probably plasma diodes), which can be formed near the observed hot spots.
Źródło:
Nukleonika; 2016, 61, 2; 161-167
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of optical spectra recorded during DPF-1000U plasma experiments with gas-puffing
Autorzy:
Zaloga, D. R.
Skladnik-Sadowska, E.
Kubkowska, M.
Ladygina, M. S.
Malinowski, K.
Kwiatkowski, R.
Sadowski, M. J.
Paduch, M.
Zielinska, E.
Makhlaj, V. A.
Powiązania:
https://bibliotekanauki.pl/articles/147780.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron density
gas-puff
optical spectrum
plasma focus
plasma stream
Opis:
The results are presented of the optical spectra measurements for free plasma streams generated with the use of the modifi ed DPF-1000U machine. This facility was recently equipped with a gas injection system (the so-called gas-puff) placed on the symmetry axis behind the central opening in the inner electrode. The DPF-1000U experimental chamber was fi lled up with pure deuterium at the initial pressure of 1.6 or 2.4 mbar. Additionally, when the use was made of the gas-puff system about 1 cm3 of pure deuterium was injected at the pressure of 2 bars. The gas injection was initiated 1.5 or 2 ms before the triggering of the main discharge. The investigated plasma discharges were powered from a condenser bank charged initially to 23 kV (corresponding to the energy of 352 kJ), and the maximum discharge current amounted to about 1.8 MA. In order to investigate properties of a dense plasma column formed during DPF-1000U discharges the use was made of the optical emission spectroscopy. The optical spectra were recorded along the line of sight perpendicular to the vacuum chamber, using a Mechelle®900 spectrometer. The recent analysis of all the recorded spectra made it possible to compare the temporal changes in the electron density of a freely propagating plasma stream for discharges without and with the gas-puffing. Using this data an appropriate mode of operation of the DPF-1000U facility could be determined.
Źródło:
Nukleonika; 2015, 60, 2; 309-314
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Progress in MJ plasma focus research at IPPLM
Autorzy:
Scholz, M.
Karpinski, L.
Krauz, V. I.
Kubeš, P.
Paduch, M.
Sadowski, M. J.
Powiązania:
https://bibliotekanauki.pl/articles/147514.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma focus
PF-1000 facility
magnetic probes
interferometry
neutron yield scaling
Opis:
The results of studies of the plasma dynamics and neutron emission on a PF-1000 facility in the stage of pinch formation are presented. The measurements were performed using various modifications of the calibrated magnetic probes, 16 frame interferometry, silver activation counters and photomultiplier tube (PMT) neutron probes. The current measurements at a distance of 40 mm from the axis of the electrodes was measured. This dependence agrees well with the known scaling, Yn similar to I4. The evolution plasma density during pinch formation and a neutron emission were study.
Źródło:
Nukleonika; 2012, 57, 2; 183-188
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of plasma interactions with tungsten targets in PF-1000U facility
Autorzy:
Ladygina, M. S.
Skladnik-Sadowska, E.
Zaloga, D. R.
Sadowski, M. J.
Kubkowska, M.
Kowalska-Strzeciwilk, E.
Krawczyk, N.
Paduch, M.
Miklaszewski, R.
Garkusha, I. E.
Powiązania:
https://bibliotekanauki.pl/articles/147524.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma-surface interaction
plasma streams
tungsten
plasma focus
PF-1000U
Opis:
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 modifi ed 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. Investigation of a target surface morphology, after its irradiation by intense plasma streams, was performed by means of an optical microscope. The observations revealed that some amounts of the electrodes material (mainly copper) were deposited upon the irradiated sample surface. In all the cases, melted zones were observed upon the irradiated target surface, and in experiments performed at the highest charging voltage there were formed some cracks.
Źródło:
Nukleonika; 2016, 61, 2; 149-153
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent measurements of soft X-ray emission from the DPF-1000U facility
Autorzy:
Surała, W.
Sadowski, M. J.
Paduch, M.
Zielinska, E.
Tomaszewski, K.
Powiązania:
https://bibliotekanauki.pl/articles/148171.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma focus
X-ray emission
X-ray images
gas puffing
filaments
hot spots
Opis:
Soft X-ray imaging is a very useful diagnostic technique in plasma-focus (PF) experiments. This paper reports results of four experimental sessions which were carried out at the DPF-1000U plasma-focus facility in 2013 and 2014. Over 200 discharges were performed at various experimental conditions. Measurements were taken using two X-ray pinhole cameras with a line of sight perpendicular to the z-axis, at different azimuthal angles (about 20° and 200°), and looking towards the centre of the PF-pinch column. They were equipped with diaphragms 1000 μm or 200–300 μm in diameter and coated with filters of 500 μm Al foil and 10 μm Be foil, respectively. Data on the neutron emission were collected with silver activation counters. For time-resolved measurements the use was made of four PIN diodes equipped with various fi lters and oriented towards the centre of the PF-column, in the direction perpendicular to the electrode axis. The recorded X-ray images revealed that when the additional gas-puff system is activated during the discharge, the stability of the discharge is improved. The data collected in these experiments confi rmed the appearance of a filamentary fi ne structure in the PF discharges. In the past years the formation of such fi laments was observed in many Z-pinch type experiments. Some of the recorded X-ray images have also revealed the appearance of the so-called hot- -spots, i.e. small plasma regions of a very intense X-ray emission. Such a phenomenon was observed before in many PF experiments, e.g. in the MAJA-PF device, but it has not been investigated so far in a large facility such as the DPF-1000U. The time-resolved measurements provided the evidence of a time lapse between the X-ray emission from plasma regions located at different distance from the anode surface. The formation of distinct ‘hot-spots’ in different instants of the DPF-1000U discharge was also observed.
Źródło:
Nukleonika; 2015, 60, 2; 303-308
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Important issues in high - current plasma experiments of the Z - pinch type
Autorzy:
Sadowski, M. J.
Scholz, M.
Powiązania:
https://bibliotekanauki.pl/articles/147694.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Z-pinch
X-pinch
wire-array Z-pinch
gas-puffed Z-pinch
plasma focus (PF)
Opis:
This paper is based on an invited lecture given at the 10th International Workshop and Summer School "Towards Fusion Energy", which was held in Kudowa Zdrój, Poland, on June 12–18, 2011. A concise review is presented of the known experimental results on various plasma Z-pinch experiments supplied by high-voltage and high-current pulsed power generators. The most important issues and the most valuable results in this domain are highlighted. A broad class of various Z-pinches is considered, including simple inter-electrode discharges, single exploding wires, so-called X-pinches, cylindrical wire-array Z-pinches, radial wire-array discharges, conical wire-array experiments, and gas-puffed Z-pinches. Non-cylindrical Z-pinch discharges (often called plasma focus experiments) are also briefly characterized. The most important characteristics of each category of experiments are outlined. Particular attention is paid to fusion-oriented high-power Z-pinch experiments and the problems encountered in experiments with various sophisticated fusion targets. The main issues in the described Z-pinch experiments are identified. Finally, new trends in the dense Z-pinch research are described.
Źródło:
Nukleonika; 2012, 57, 1; 11-24
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical emission spectroscopy of plasma streams in PF-1000 experiments
Autorzy:
Jakubowska, K.
Kubkowska, M.
Skladnik-Sadowska, E.
Malinowski, K.
Marchenko, A. K.
Paduch, M.
Sadowski, M. J.
Scholz, M.
Powiązania:
https://bibliotekanauki.pl/articles/146628.pdf
Data publikacji:
2011
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
dense plasma focus (DPF)
optical emission spectroscopy
deuterium Balmer series
Ar II lines
electron density
Boltzmann plot
Opis:
The optical spectroscopy in the visible range was used to determine properties of the dense magnetized plasma generated in the PF-1000, a 1 MJ plasma focus device operating in the Institute of Plasma Physics and Laser Microfusion (IPPLM) in Warsaw, Poland. The experiments were performed in a vacuum chamber pumped out to the basic pressure of 2 x 10.5 hPa. The initial pressure of the pure deuterium filling was 2.9 hPa, while that of the deuterium--argon mixture was 1.07 hPa of D2 and 0.13 hPa of Ar. The deuterium-plasma emission contained the Balmer series (Dalfa, Dbeta and Dgamma) and a few distinct copper (Cu I) lines originating from the inner electrode material. The emission of the deuterium-argon plasma was rich in Ar II lines. The electron density (ne), averaged over line of sight, of order of 1016 cm.3 was calculated on the basis of the Dalfa and Dbeta emission only, because the D�ż line was strongly self-absorbed. A group of the Ar II spectral lines was used to estimate the excitation temperature (Texc = 3 eV) by means of a Boltzmann plot. Additionally, the temporal evolution of the electron density was determined on basis of the Stark broadening of the Dalfa and Dgamma lines.
Źródło:
Nukleonika; 2011, 56, 2; 125-129
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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