Wyniki wyszukiwania - BazTech

1

Studies of plasma interactions with tungsten targets in PF-1000U facility

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.

Nukleonika

|

2016

|

Vol. 61, No. 2

149--153

EN

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.

2

Study of tungsten surface interaction with plasma streams at DPF-1000U

Ladygina M. S., Skladnik-Sadowska E., Zaloga D. R., Malinowski K., Sadowski M. J., Kubkowska M., Kowalska-Strzeciwilk E., Paduch M., Zielinska E., Miklaszewski R., Garkusha I. E., Gribkov V. A.

Nukleonika

|

2015

|

Vol. 60, No. 2

293--296

EN

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 stream (i.e., the plasma stream observed without any target inside the vacuum chamber) was estimated on the basis of the half-width of the Dβ spectral line, taking into account the linear Stark effect. For a freely propagating plasma stream the maximum electron density amounted to about 1.3 × 1017 cm–3 and was reached during the maximum plasma compression. The plasma electron density depends on the initial conditions of the experiments. It was thus important to determine first the plasma flow characteristics before attempting any target irradiation. These data were needed for comparison with plasma characteristics after an irradiation of the investigated target. In fact, spectroscopic measurements performed during interactions of plasma streams with the investigated W samples showed many WI and WII spectral lines. The surface erosion was determined from mass losses of the irradiated samples. Changes on the surfaces of the irradiated samples were also investigated with an optical microscope and some sputtering and melting zones were observed.

3

Damage and modification of materials produced by pulsed ion and plasma streams in Dense Plasma Focus device

Pimenov V. N., Demina E. V., Ivanov L. I., Gribkov V. A., Dubrovsky A. V., Ugaste U., Laas T., Scholz M., Miklaszewski R., Kolman B., Tartari A.

Nukleonika

|

2008

|

Vol. 53, No. 3

111-121

EN

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 functional components of thermonuclear fusion devices with magnetic (MPC) and inertial (IPC) plasma confinement, as well as for working chambers of plasma and accelerator devices. The main features of the materials are low-activation and radiation-resistant properties. On the basis of the investigations a significant progress was achieved in understanding of dynamics of high-energy nano- and micro-second pulsed streams in DPF from one side as well as on the mechanisms of their influence upon materials under irradiation from the other one. We demonstrated that this approach can be useful for certain tests of plasma-facing materials (e.g. W for MPC and stainless steels for IPC) and of structural (construction) elements of the above-mentioned devices subjected to pulsed high-energy radiation streams. The results obtained suggest also that DPF devices can be used in new pulse technologies for material treatment by means of powerful nanosecond and microsecond pulses of plasma and ion streams.

4

Surface and bulk processes in materials induced by pulsed ion and plasma beams at Dense Plasma Focus devices

Pimenov V., Maslyaev S., Ivanov L., Dyomina E., Gribkov V., Dubrovsky A., Scholz M., Miklaszewski R., Ugaste U., Kolman B.

Nukleonika

|

2006

|

Vol. 51, nr 1

71-78

EN

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 both surface and bulk of the material positioned at the cathode part of the DPF device have been considered. Advanced directions of DPF use for scientific and applied problems of radiation material science were determined.

5

PF-6 an effective plasma focus as a source of ionizing radiation and plasma streams for application in material technology, biology and medicine

Gribkov V., Dubrovsky A., Scholz M., Jednorog S., Karpiński L., Tomaszewski K., Paduch M., Miklaszewski R., Pimenov V., Ivanov L. I., Dyomina E. V., Maslyaev S. A., Orlova M. A.

Nukleonika

|

2006

|

Vol. 51, nr 1

55-62

EN

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. These results are compared with the analogous information received at the biggest facility PF-1000. It is shown that it is possible to have about the same power flux density (in the range of 105 109 W/cm2) in both devices however in different areas. Doses of soft X-rays produced by the device within the resists for the goals of microlithography and micromachining appear to be several times less that it is with the conventional X-ray tube. In biological application of this device, medium- and hard-energy X-rays are exploited in the field of radioenzymology. It was found that the necessary dose producing activation/inactivation of enzymes can be by several orders of magnitude lower if used at a high-power flux density in comparison with those received with isotope sources. In medicine, short-life isotope production for the goals of the positron emission tomography (medicine diagnostics) is possible by means of the fast ions generated within DPF. All these experiments are discussed in the framework of pulsed radiation physics and chemistry in its perfect sense thereto the criteria are formulated.

6

Influence of powerful pulses of hydrogen plasma upon materials in PF-1000 device

Pimenov V., Gribkov V., Dubrovsky A., Mezzetti F., Scholz M., Ugaste U., Dyomina E., Ivanov L., Maslyaev S., Miklaszewski R., Borowiecki M., De Chiara P., Pizzo L., Szydlowski A., Volobuev I. V.

Nukleonika

|

2002

|

Vol. 47, nr 4

155-162

EN

The results of experimental investigations of powerful hydrogen plasma jets and fast ion beams interaction with various materials (austenitic chromium-manganese steels, pure vanadium, tungsten, graphite, copper, and their alloys: Cu-4 mass% Ni and Cu-10 mass% Ga) are presented. The materials were placed on the discharge axis of the PF-1000 device and irradiated with fluxes of fast ions (of energy in the range from tens keV up to several MeV) and with plasma streams (of power flux density q~(108 109) W/cm2). It was found that the fast ions and plasma streams caused different damages to the aforementioned materials. A diverse character of the damages to the individual investigated material was revealed. Some peculiarities of the process as well as the correlation between the surface density of the "macroscopic" structural defects (blisters and craters) and the fluence of the fast ions implanted in the specimen are discussed.

7

Recent progress in 1 MJ Plasma-Focus research

Scholz M., Karpiński L., Paduch M., Tomaszewski K., Miklaszewski R., Szydlowski A.

Nukleonika

|

2001

|

Vol. 46, nr 1

35-39

EN

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.

8

Experimental study of a powerful energy flow effect on materials in PF-1000 installation

Borowiecki M., De Chiara P., Dubrovsky A. V., Dyomina E. V., Gribkov V. A., Ivanov L. I., Maslyaev S. A., Mezzetti F., Miklaszewski R., Pimenov V. N., Pizzo L., Scholz M., Szydlowski A., Ugaste Y. E., Volobuev I. V.

Nukleonika

|

2001

|

Vol. 46, suppl. 1

117--122

EN

The report describes some of the results obtained in an experimental study of the impact of a powerful plasma stream and a fast ion beam generated in a PF-1000 device on different materials perspective for the use in radiation loaded parts of pulsed plasma installations. Investigations were done during and after the interaction processes. It is shown that in case of irradiation of samples only by high power flux density plasma streams the effect of detachment still preserved. At the same time a low power flux density high-energy ion beam plays an important role in the process of saturation of the irradiated material by hydrogen.

9

Investigation of dynamic and stability of laser-produced plasma in strong external magnetic field.

Pisarczyk T., Kasperczuk A., Miklaszewski R., Zakharov Y.P.

Optica Applicata

|

2000

|

Vol. 30, nr 1

41-59

EN

The paper presents results of studies of the behaviour of a laser-produced plasma in strong external axial and transverse magnetic field of 5-20 T in induction generated from a flat teflon target at the laser power densities of about 10/sup 14/ Wcm/sup -2/. The investigations were carried on by means of three-frame interferometry and a non-contact magnetic probe, the so-called remote magnetic probe (RMP). The dynamics of the process of creation of the diamagnetic cavity, its shape and dimensions have been determined. Also computer simulation of plasma expansion by a 2D MHD code was made.

10

PF-1000 device

Scholz M., Miklaszewski R., Gribkov V., Mezzetti F.

Nukleonika

|

2000

|

Vol. 45, nr 3

155-158

EN

The paper presents the megajoule plasma focus facility operated at IPPLM. In order to study plasma focus (PF) discharges several diagnostics tools have been prepared. The preliminary observations of current sheath motion, as well as measurements of the current signals are reported.

11

On tuning mechanisms of DPF devices

Tsybenko S., Miklaszewski R.

Nukleonika

|

2000

|

Vol. 45, nr 3

163-165

EN

A global instability theory of pinching plasmas allows us to justify the well-known empirical facts of the use of a mismatched dense plasma focus (DPF) and heavy inert gas admixtures. We assume that an instability of tangential discontinuity is responsible for the instability of a current-carrying plasma column. To inhibit development of a tangential discontinuity in a plasma focus, an array of insulator fibers or metallic wires placed on the anode near the axis of a discharge camera can be used.