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Tytuł:
The role of anomalous resistivities in Plasma Focus discharges
Autorzy:
Bruzzone, H.
Powiązania:
https://bibliotekanauki.pl/articles/148185.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
anomalous resistivity
pinches
plasma focus
Opis:
The existence of plasma microturbulence in Plasma Focus (PF) devices is a widely accepted fact within the PF community. This microturbulence must be generated as a final stage of microscopic instabilities, which could develop during certain phases of the plasma evolution. Among the candidate instabilities to occur in these devices, the lower hybrid drift instability is the one with better possibilities, because its triggering condition (electron drift velocity approaching ion thermal velocity) has reasonable chances to be fulfilled. The main effect of the development of this instability is the modification of the collision frequencies in the plasma, which adds an anomalous term to the plasma resistivity. The theory for evaluating this extra term exists, and has been already used in PF 1D numerical simulations and in Z-pinch calculations. The role of this anomalous resistivity in PF behaviour has been the subject of considerable speculations. In this work, a 1D MHD (magnetohydrodynamics) calculation of the pinch stage in a PF device will be presented, including anomalous resistivity effects and their influence on electric fields and the discharge current are discussed.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 3-7
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Results of large scale Plasma-Focus experiments and prospects for neutron yield optimization
Autorzy:
Sadowski, M.
Scholz, M.
Powiązania:
https://bibliotekanauki.pl/articles/147144.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
neutron yield
nuclear target
optimization
plasma focus
Opis:
This paper summarizes results of the recent Plasma-Focus (PF) studies carried out with different PF facilities in Poland, which were operated at energies ranging from 100 kJ to about 1000 kJ. Particular attention has been paid to currentsheath (CS) dynamics, the emission of pulsed X-rays, fast electron beams, energetic ion beams, and fusion-produced neutrons. Some efforts, undertaken in order to increase the neutron emission, have been described. In particular, nuclear targets made of D2O-ice layers, which were deposited upon special cryogenic devices, have been applied in the PF-360 machine. An increase in the neutron yield from 2.4×1010 up to 3.8×1010 neutrons per shot has been achieved in 130-kJ discharges. With the PF-1000 machine, for the first time the well-formed plasma pinch columns were obtained in PF discharges performed at 1 MJ, and the neutron yield of 2×1011 neutrons per shot was achieved.
Źródło:
Nukleonika; 2002, 47, 1; 31-37
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the influence of gas puff loads on plasma focus dynamics
Autorzy:
Schmidt, H.
Powiązania:
https://bibliotekanauki.pl/articles/971523.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
computer modelling
gas puffing
nuclear fusion
nuclear reactions
plasma focus
Z-pinch
Opis:
The plasma focus is a source of pulsed radiation, which is of interest in various fields of physics and technology. Applications include soft X-ray microscopy, soft X-ray and electron beam lithography. The plasma focus is also a highly efficient source of fast neutrons. If one applies gas puffing instead of static filling, decoupling of plasma conditions in the breakdown and compression phases can be achieved. Results of experiments with a fast valve and accompanying 2D modelling of the dynamic gas target are presented. Among other advantages of gas puffing, neutron yield could be increased up to a factor of three in appropriate experiments. The concept of gas puffing has been extensively investigated in many Z-pinch experiments including multiple gas puffs. It seems desirable to increase the efforts to understand and optimise the gas puffing option for small and large plasma focus devices.
Źródło:
Nukleonika; 2001, 46, 1; 15-19
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Installations based on high efficiency high repetition rate miniature DPF chambers for material science
Autorzy:
Dubrovsky, A.
Gribkov, V.
Powiązania:
https://bibliotekanauki.pl/articles/146795.pdf
Data publikacji:
2000
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
dense plasma focus (DPF)
miniature focus chamber
PF instalation
Opis:
The report describes two DPF installations based on a miniature plasma focus chamber: the installation PF-3 of the energy store W = 3 kJ and the installation PF-0.2 (W = 200 J). The possibility of an adaptation of the small DPF device for the experimental samples irradiation is reported. A new construction intended for experiments with samples of various materials is presented.
Źródło:
Nukleonika; 2000, 45, 3; 159-162
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on a low energy plasma focus discharge
Autorzy:
Allam, T. M.
Abd El-Latif, S. T.
Soliman, H. M.
Powiązania:
https://bibliotekanauki.pl/articles/146872.pdf
Data publikacji:
2007
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma focus
plasma sheath dynamics
magnetic force
focusing action
Opis:
This paper is devoted to the experimental and theoretical study of plasma current sheath behavior for a low energy plasma focus device operating at a filling nitrogen gas pressure of 3.3 torr, and at a stored energy of 1.2 kJ. Axial distribution profiles of plasma current sheath (PCS) characteristics such as propagation velocity Vz, acceleration az, azimuthal magnetic field induction Btheta, and magnetic force per unit volume Fz/m3 along the coaxial electrodes system was performed from a magnetic probe and miniature Rogovsky coil signals. The experimental results showed that the axial distribution of Vz, az, Btheta and Fz has approximately the same profile and the maximum value of these parameters was detected nearly at a mid-distance of coaxial electrodes system. Theoretical description of PCS dynamics at the axial phase, based on a snowplough, was estimated as a function of discharge time. These data were compared with the received experimental results.
Źródło:
Nukleonika; 2007, 52, 3; 87-91
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tomographic system based on Plasma Focus X-rays
Autorzy:
Venere, M.
Moreno, C. H.
Clausse, A.
Barbuzza, R.
Del Fresno, M.
Powiązania:
https://bibliotekanauki.pl/articles/147461.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
defectoscopy
image processing
plasma focus applications
tomographic reconstruction
X-rays
Opis:
A system oriented to develop an image processing system, which takes advantage of radiation flashes from a plasma focus, by optimizing the emission-detection-reconstruction procedure, is presented. A computer technique for 3D reconstructions was combined with radiographic images of objects X-rayed with a compact plasma focus. The technique is able to automatically determine the position of the rotation axis, reconstruct the 3D-attenuation map, and display inner cuts. The system was demonstrated in introspective tomographic imaging of a stainless steel BNC elbow.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 93-94
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of deuteron motion in a filamentary Plasma-Focus pinch column for different configurations of filaments
Autorzy:
Pasternak, A.
Sadowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/146934.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
deuterons
filamentary pinch
ion trajectories
numerical modeling
plasma focus
Opis:
The motion of deuterons in dynamical filamentary configurations of a PF pinch column has been studied with a three-dimensional numerical model. Apart from magnetic fields, the motion-induced electrical fields as well as ion-ion and ion-electron collisions have been included in the equations of deuteron motion. Calculations were performed for different numbers of filaments and its spatial distributions under different initial conditions. Energy of ions was assumed to be from 10 keV up to 200 keV. The results obtained have shown many possible modes of ion motion and have demonstrated that the current filaments can cause peculiarities observed in the angular distribution of deuterons emitted from the PF pinch column.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 29-32
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent progress in 1 MJ Plasma-Focus research
Autorzy:
Scholz, M.
Karpiński, L.
Paduch, M.
Tomaszewski, K.
Miklaszewski, R.
Szydlowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/147553.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
neutron emission
plasma focus
scaling laws
soft X-ray radiation
Opis:
The paper reports on actual operational characteristics of the PF-1000 facility and it presents results of the first neutron experiments performed with a new set of large Mather-type electrodes, which were designed for shots up to 1000 kJ. Dynamics of a current-sheath was studied by means of two high-speed streak cameras and a two-frame camera. The last one was used for the side-on observation of the pinch column. The high-speed streak pictures were taken side-on behind slits oriented in the radial or axial direction. On the basis of the pictures taken behind the radial slit, average values of the radial compression and expansion velocities were estimated. Time-resolved X-ray signals were measured with PIN diodes covered by different filters, and they were compared with other traces (voltage waveforms, dI/dt signals, and neutron-induced pulses) in order to determine their correlation. The total neutron yield (Ytot), i.e. the number of neutrons produced during a single discharge and emitted in various directions, was measured by means of several silver-activation detectors placed at different angles around the PF-1000 experimental chamber.
Źródło:
Nukleonika; 2001, 46, 1; 35-39
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary study on X-ray source from Plasma Focus device for fast radiography
Autorzy:
Da Re, A.
Mezzetti, F.
Tartari, A.
Verri, G.
Rapezzi, L.
Gribkov, V. A.
Powiązania:
https://bibliotekanauki.pl/articles/147243.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma focus
X-ray sources
Opis:
Plasma derived flash X-ray sources may find potential applications in medicine and industry. Notwithstanding, as is the case of Plasma Focus (PF) devices, their characterisation in term of photon energy, temporal and spatial beam stability is far to be considered satisfactory. In this work, a radiographic approach, which avoids the effects caused by the intrinsic instability of the pinch output of a PF machine, is proposed and an attenuation curve can be attained even in presence of Xray emission instability. Using two radiographic films for each shot exposition symmetrically positioned and collimated to the pinch region the mean energy of the photons in the X-ray beam are evaluated. The X-ray emission symmetry from the pinch region was then utilised to control the validity of the proposed methodology.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 123-125
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:
On possible formulation of problems of a Dense Plasma Focus used in material sciences
Autorzy:
Gribkov, V.
Powiązania:
https://bibliotekanauki.pl/articles/146787.pdf
Data publikacji:
2000
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
cumulative plasma streams
dense plasma focus (DPF)
electron beam
ion beam
material sciences
neutrons
X-rays
Opis:
The paper describes various possibilities at can be given by the use of dense plasma focus (DPF) device in material sciences. Main distinguishing features of such a device – availability of several different types of hard radiation and its high power flux density – determine the niche of applications of this type devices in the field. Some directions of materials investigation and treatment, which can be developed at present time, are discussed.
Źródło:
Nukleonika; 2000, 45, 3; 149-153
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Plasma Focus discharges in the PF-360 facility with additional D2 gaspuffed targets
Autorzy:
Stanislawski, J.
Baranowski, J.
Sadowski, M.
Zebrowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/147013.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
current sheath
deuteron beams
gas puffing
neutron yield
plasma focus
Opis:
The paper describes experimental studies of Plasma-Focus (PF) discharges carried out within the modernized PF- 360 facility, which was operated with an additional D2-gas puffing into the region of the collapsing current sheath and PF pinch formation, i.e. into space in front of the electrode outlet. The main aim of these studies was to increase a neutron yield from PF discharges by using fast deuteron beams, which are usually emitted from a pinch column and which can interact with additional D2-gas target.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 73-75
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study of X-ray emission yield in a Filippov-type Plasma Focus operating in neon and neon-krypton mixture
Autorzy:
Babazadeh, A.
Roshan, M.
Kiai, S.
Powiązania:
https://bibliotekanauki.pl/articles/147028.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Filippov-type plasma focus
gas admixture
X-ray
Opis:
Since the installation of PF-DENA at AEOI about one year ago, we performed quantitative studies of variation of X-ray radiations from a new Filippov-type plasma focus device: Dena (90 kJ, 25 kV, 288 ěF). The operating gas was neon at a constant low pressure of 1 torr and different pressures of krypton admixture (up to 0.3 torr), with the discharge voltage up to 18 kV. For a charging voltage of 17 kV with 41 kJ stored energy and spark gap pressure of 1.2×10-2 torr, the maximum soft and little hard X-ray (SXR-HXR) emission is found for the neon, resulting in a total SXR yield of 2 V/shot measured by silicon semiconductor diode detectors. Concerning the effect of krypton admixture, a maximum intensity of SXR radiation has been observed at low krypton pressure that is about 1 V/shot. At higher pressure, the quantity of the SXR emission decreases down to zero. However, the maximum intensity of the HXR radiation yield in the same pressure range was found to be 2.5 V/shot. By increasing the pressure of krypton up to 0.3 torr, the results show that the krypton admixture gas generally causes, a decrease of the SXR radiation yield down to zero, whereas, the HXR emission yield carries a maximum value at the optimum pressure of krypton that is about 0.1 torr. Nevertheless, the pressure increments of krypton admixture lead to decreasing in the discharge voltage for the maximum X-ray production.
Źródło:
Nukleonika; 2002, 47, 3; 123-125
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of dense deuterium plasma pulses on materials in Plasma Focus device
Autorzy:
Ivanov, L.
Pimenov, V.
Maslyaev, S.
Dyomina, E.
Gribkov, V.
Mezzetti, F.
DeChiara, P.
Powiązania:
https://bibliotekanauki.pl/articles/146708.pdf
Data publikacji:
2000
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
high-temperature plasma
material science
plasma focus
Opis:
Experiments on the influence of high-temperature plasma nanosecond pulse radiation, as generated in plasma focus device, on the W-Cu pseudoalloy, V-35at%Ti alloy, austenitic chromium-manganese 10Cr12Mn20W and 25Cr12Mn20W steels have been carried out. Features of damages, phase-structural transformations and chemical content changes in those materials under such irradiation were investigated.
Źródło:
Nukleonika; 2000, 45, 3; 203-207
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pinch modes in the SPEED2 plasma focus
Autorzy:
Kies, W.
Decker, G.
Berntien, U.
Sidelnikov, U.
Glushkov, D.
Koshelev, K.
Simanovskij, D.
Bobashev, S.
Powiązania:
https://bibliotekanauki.pl/articles/146993.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
pinch plasma
pinch stability
plasma focus
plasma radiation
radiation source
Opis:
Deuterium discharges in the SPEED2 plasma focus (80 kJ, 200 kV, 2 MA, 400 ns) have been found unexpectedly stable within the operational regime as a neutron source. Only at higher filling pressures (above 6 mbar) sometimes m=0 instabilities appeared in the pinch column, especially in discharges of lower efficiency (moderate dynamics and neutron yield). Enhancing the electromagnetic radiation by doping these discharges with heavy gases (e.g. neon, argon) distinctly two pinch modes are produced, the micropinch mode (MPM) or the stable column mode (SCM), with a transition regime where the initial SCM is followed by the MPM. Micropinches are local radiative collapses initiated by m=0 instabilities of low-energy- density pinch plasmas. These instabilities and the successive micropinches can be suppressed by kinetic deuterons produced during dynamical compression of high-energy-density deuterium plasma sheaths. Depending on the relaxation of this fast deuteron component the pinch column can be stabilized for several tens of nanoseconds. While the short-lived (appr. 1 ns) micropinches erratically appear as point-like successive flashes along the pinch axis with temperatures about 1 keV and about solid density the reproducible SCM, optimized with respect to the compression ratio, forms a powerful linear radiation source of temperatures and densities similar to the MPM. The SCM needs powerful (fast) drivers in order to use the kinetic ion stabilization, but not necessarily MA currents as available from the SPEED2 driver. This opens the possibility to establish the SCM also in compact experiments like SPEED3 (8 kJ, 80 kV, 0.8 MA, 300 ns) or even SPEED4 (2 kJ, 40 kV, 250 kA, 300 ns).
Źródło:
Nukleonika; 2001, 46, 1; 9-14
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł

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