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Sample records for thermal plasma generating

  1. Inductive thermal plasma generation applied for the materials coating

    International Nuclear Information System (INIS)

    Pacheco, J.; Pena, R.; Cota, G.; Segovia, A.; Cruz, A.

    1996-01-01

    The coatings by thermal plasma are carried out introducing particles into a plasma system where they are accelerated and melted (total or partially) before striking the substrate to which they adhere and are suddenly cooled down. The nature of consolidation and solidification of the particles allows to have control upon the microstructure of the deposit. This technique is able to deposit any kind of material that is suitable to be merged (metal, alloy, ceramic, glass) upon any type of substrate (metal, graphite, ceramic, wood) with an adjustable thickness ranging from a few microns up to several millimeters. The applications are particularly focused to the coating of materials in order to improve their properties of resistance to corrosion, thermal and mechanical efforts as well as to preserve the properties of the so formed compound. In this work the electromagnetic induction phenomenon in an ionized medium by means of electric conductivity, is described. Emphasis is made on the devices and control systems employed in order to generate the thermal plasma and in carrying out the coatings of surfaces by the projection of particles based on plasma

  2. Spontaneous generation of electromagnetic waves in plasmas with electron thermal flux

    International Nuclear Information System (INIS)

    Okada, Toshio

    1977-01-01

    Spontaneous generation of propagating electromagnetic fields due to a microinstability is investigated for plasmas which convey electron thermal fluxes. The following two cases are examined: 1) Electromagnetic fields spontaneously excited by electrons in a velocity distribution of skewed Maxwellian type. 2) Electromagnetic waves generated by electrons in a velocity distribution which consists of a main part and a high energy part. In this case, the electron thermal flux can be very high. In both cases, induced electromagnetic waves with relatively low frequencies propagate parallel to the direction of Thermal flux. (auth.)

  3. Thermal plasmas: fundamental aspects

    International Nuclear Information System (INIS)

    Fauchais, P.

    2005-01-01

    This article treats of thermal plasmas, i.e. mainly produced by electric arcs and RF discharges. Their main characteristic is that they are generated at a pressure close to the atmospheric pressure (between 10 4 and 10 6 Pa) and refer to the classical kinetics of the Boltzmann equation. Because of the pressure, the collisions between particles are numerous and ionization is mainly due to a thermal effect. They correspond to electron densities between 10 20 and 10 24 m -3 and temperatures between 6000 and 25000 K. In these plasmas, the electric fields and the average free trajectories are too weak to generate a ionization state by direct inelastic collision. Ionization is thus essentially a thermal phenomenon due to elastic collisions. This article presents: 1 - the particles present in a plasma: definition, energy states; 2 - characteristic data: collisions, average free path and collision cross-section, distribution function, ionization types, charged particles mobility inside an electric field, scattering, Debye length; 3 - plasmas at the thermodynamical equilibrium: conditions of equilibrium, calculation of composition, thermodynamic properties, transport properties, radiation; 4 - thermal plasmas away from equilibrium: conditions of non-equilibrium, calculation of plasma composition, calculation of transport properties, quenching phenomenon. (J.S.)

  4. Thermal Plasma Generators with Water Stabilized Arc

    Czech Academy of Sciences Publication Activity Database

    Hrabovský, Milan

    2009-01-01

    Roč. 2, č. 1 (2009), s. 99-104 ISSN 1876-5343 R&D Projects: GA ČR GA202/08/1084 Institutional research plan: CEZ:AV0Z20430508 Keywords : Thermal plasma * plasma torch * Gerdien arc Subject RIV: BL - Plasma and Gas Discharge Physics http://www.bentham.org/open/toppj/openaccess2.htm

  5. Thermal Plasma decomposition of fluoriated greenhouse gases

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Soo Seok; Watanabe, Takayuki [Tokyo Institute of Technology, Yokohama (Japan); Park, Dong Wha [Inha University, Incheon (Korea, Republic of)

    2012-02-15

    Fluorinated compounds mainly used in the semiconductor industry are potent greenhouse gases. Recently, thermal plasma gas scrubbers have been gradually replacing conventional burn-wet type gas scrubbers which are based on the combustion of fossil fuels because high conversion efficiency and control of byproduct generation are achievable in chemically reactive high temperature thermal plasma. Chemical equilibrium composition at high temperature and numerical analysis on a complex thermal flow in the thermal plasma decomposition system are used to predict the process of thermal decomposition of fluorinated gas. In order to increase economic feasibility of the thermal plasma decomposition process, increase of thermal efficiency of the plasma torch and enhancement of gas mixing between the thermal plasma jet and waste gas are discussed. In addition, noble thermal plasma systems to be applied in the thermal plasma gas treatment are introduced in the present paper.

  6. Technological challenges in thermal plasma production

    International Nuclear Information System (INIS)

    Ramakrishnan, S.

    1995-01-01

    Thermal plasmas, generated by electric arc discharges, are used in a variety of industrial applications. The electric arc is a constricted electrical discharge with a high temperature in the range 6000-25,000 K. These characteristics are useful in plasma cutting, spraying, welding and specific areas of material processing. The thermal plasma technology is an enabling process technology and its status in the market depends upon its advantages over competing technologies. A few technological challenges to enhance the status of plasma technology are to improve the utilisation of the unique characteristics of the electric arc and to provide enhanced control of the process. In particular, new solutions are required for increasing the plasma-material interaction, controlling the electrode roots and controlling the thermal power generated by the arcing process. In this paper, the advantages of plasma technology, its constraints and future challenges for technology developments are highlighted. 36 refs., 14 figs

  7. Cell death induced on cell cultures and nude mouse skin by non-thermal, nanosecond-pulsed generated plasma.

    Directory of Open Access Journals (Sweden)

    Arnaud Duval

    Full Text Available Non-thermal plasmas are gaseous mixtures of molecules, radicals, and excited species with a small proportion of ions and energetic electrons. Non-thermal plasmas can be generated with any high electro-magnetic field. We studied here the pathological effects, and in particular cell death, induced by nanosecond-pulsed high voltage generated plasmas homogeneously applied on cell cultures and nude mouse skin. In vitro, Jurkat cells and HMEC exhibited apoptosis and necrosis, in dose-dependent manner. In vivo, on nude mouse skin, cell death occurred for doses above 113 J/cm(2 for the epidermis, 281 J/cm(2 for the dermis, and 394 J/cm(2 for the hypodermis. Using electron microscopy, we characterized apoptosis for low doses and necrosis for high doses. We demonstrated that these effects were not related to thermal, photonic or pH variations, and were due to the production of free radicals. The ability of cold plasmas to generate apoptosis on cells in suspension and, without any sensitizer, on precise skin areas, opens new fields of application in dermatology for extracorporeal blood cell treatment and the eradication of superficial skin lesions.

  8. Power supply controlled for plasma torch generation

    International Nuclear Information System (INIS)

    Diaz Z, S.

    1996-01-01

    The high density of energy furnished by thermal plasma is profited in a wide range of applications, such as those related with welding fusion, spray coating and at the present in waste destruction. The waste destruction by plasma is a very attractive process because the remaining products are formed by inert glassy grains and non-toxic gases. The main characteristics of thermal plasmas are presented in this work. Techniques based on power electronics are utilized to achieve a good performance in thermal plasma generation. This work shown the design and construction of three phase control system for electric supply of thermal plasma torch, with 250 kw of capacity, as a part of the project named 'Destruction of hazard wastes by thermal plasma' actually working in the Instituto Nacional de Investigaciones Nucleares (ININ). The characteristics of thermal plasma and its generation are treated in the first chapter. The A C controllers by thyristors applied in three phase arrays are described in the chapter II, talking into account the power transformer, rectifiers bank and aliasing coil. The chapter III is dedicated in the design of the trigger module which controls the plasma current by varying the trigger angle of the SCR's; the protection and isolating unit are also presented in this chapter. The results and conclusions are discussed in chapter IV. (Author)

  9. Development of plasma properties along thermal plasma jet generated by hybrid water-argon torch

    Czech Academy of Sciences Publication Activity Database

    Kavka, Tetyana; Hrabovský, Milan

    2002-01-01

    Roč. 52, supplement D (2002), s. 637-642 ISSN 0011-4626. [Symposium on Plasma Physics and Technology/20th./. Prague, 10.06.2002-13.06.2002] Institutional research plan: CEZ:AV0Z2043910 Keywords : thermal plasma, plasma jet, enthalpy probe Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.311, year: 2002

  10. Thermal plasma waste treatment

    International Nuclear Information System (INIS)

    Heberlein, Joachim; Murphy, Anthony B

    2008-01-01

    Plasma waste treatment has over the past decade become a more prominent technology because of the increasing problems with waste disposal and because of the realization of opportunities to generate valuable co-products. Plasma vitrification of hazardous slags has been a commercial technology for several years, and volume reduction of hazardous wastes using plasma processes is increasingly being used. Plasma gasification of wastes with low negative values has attracted interest as a source of energy and spawned process developments for treatment of even municipal solid wastes. Numerous technologies and approaches exist for plasma treatment of wastes. This review summarizes the approaches that have been developed, presents some of the basic physical principles, provides details of some specific processes and considers the advantages and disadvantages of thermal plasmas in waste treatment applications. (topical review)

  11. SUPERFAST THERMALIZATION OF PLASMA

    Science.gov (United States)

    Chang, C.C.

    1962-06-12

    A method is given for the superfast thermalization of plasma by shock conversion of the kinetic energy stored in rotating plasma rings or plasmoids colliding at near supersonic speeds in a containment field to heat energy in the resultant confined plasma mass. The method includes means for generating rotating plasmoids at the opposite ends of a Pyrotron or Astron containment field. The plasmoids are magnetically accelerated towards each other into the opposite ends of time containment field. During acceleration of the plasmoids toward the center of the containment field, the intensity of the field is sequentially increased to adiabatically compress the plasmoids and increase the plasma energy. The plasmoids hence collide with a violent shock at the eenter of the containment field, causing the substantial kinetic energy stored in the plasmoids to be converted to heat in the resultant plasma mass. (AEC)

  12. Non-thermal Plasma and Oxidative Stress

    Science.gov (United States)

    Toyokuni, Shinya

    2015-09-01

    Thermal plasmas and lasers have been used in medicine to cut and ablate tissues and for coagulation. Non-equilibrium atmospheric pressure plasma (NEAPP; non-thermal plasma) is a recently developed, non-thermal technique with possible biomedical applications. Although NEAPP reportedly generates reactive oxygen/nitrogen species, electrons, positive ions, and ultraviolet radiation, few research projects have been conducted to merge this technique with conventional free radical biology. Recently, Prof. Masaru Hori's group (Plasma Nanotechnology Research Center, Nagoya University) developed a NEAPP device with high electron density. Here electron spin resonance revealed hydroxyl radicals as a major product. To merge non-thermal plasma biology with the preexisting free radical biology, we evaluated lipid peroxidation and DNA modifications in various in vitro and ex vivo experiments. Conjugated dienes increased after exposure to linoleic and alfa-linolenic acids. An increase in 2-thiobarbituric acid-reactive substances was also increased after exposure to phosphatidylcholine, liposomes or liver homogenate. Direct exposure to rat liver in medium produced immunohistochemical evidence of 4-hydroxy-2-nonenal- and acrolein-modified proteins. Exposure to plasmid DNA induced dose-dependent single/double strand breaks and increased the amounts of 8-hydroxy-2'-deoxyguanosine and cyclobutane pyrimidine dimers. These results indicate that oxidative biomolecular damage by NEAPP is dose-dependent and thus can be controlled in a site-specific manner. Simultaneous oxidative and UV-specific DNA damage may be useful in cancer treatment. Other recent advancements in the related studies of non-thermal plasma in Nagoya University Graduate School of Medicine will also be discussed.

  13. The low-current low-temperature plasma generators

    International Nuclear Information System (INIS)

    Dautov, G.Yu.

    2000-01-01

    In this article, the results of low-current gas-discharge plasma generator investigations carried out by a group of scientists from the Kazan' Aviation Institute are presented. When considered necessary, the results are compared with the data obtained by other authors. The basic configurations and theoretical calculation peculiarities of plasma generators are described. The electrical, thermal and energy characteristics of discharges in gas flows, as well as summarised empirical formulae and experimental data necessary for calculations and design of plasma devices are presented. (author)

  14. Power supply controlled for plasma torch generation; Fuente de alimentacion controlada para la generacion de un plasma

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Z, S

    1997-12-31

    The high density of energy furnished by thermal plasma is profited in a wide range of applications, such as those related with welding fusion, spray coating and at the present in waste destruction. The waste destruction by plasma is a very attractive process because the remaining products are formed by inert glassy grains and non-toxic gases. The main characteristics of thermal plasmas are presented in this work. Techniques based on power electronics are utilized to achieve a good performance in thermal plasma generation. This work shown the design and construction of three phase control system for electric supply of thermal plasma torch, with 250 kw of capacity, as a part of the project named `Destruction of hazard wastes by thermal plasma` actually working in the Instituto Nacional de Investigaciones Nucleares (ININ). The characteristics of thermal plasma and its generation are treated in the first chapter. The A C controllers by thyristors applied in three phase arrays are described in the chapter II, talking into account the power transformer, rectifiers bank and aliasing coil. The chapter III is dedicated in the design of the trigger module which controls the plasma current by varying the trigger angle of the SCR`s; the protection and isolating unit are also presented in this chapter. The results and conclusions are discussed in chapter IV. (Author).

  15. Non-thermal plasma at atmospheric pressure for ozone generation and volatile organic compounds decomposition

    International Nuclear Information System (INIS)

    Pekarek, S.; Khun, J.

    2006-01-01

    The non-thermal plasma technologies based on electrical discharges play an important role in ecological applications. The classical corona discharge is however relatively low power discharge. With the aim to extend its current-voltage range we studied hollow needle-to-plate DC corona discharge enhanced by the flow of a gas through the needle electrode. With this type of the discharge we performed an extensive study of ozone generation and volatile organic compounds decomposition. We found that supply of air through the needle substantially increases current-voltage range of the discharge in comparison with classical pin-to-plate corona discharge. Consequently the ozone generation as well as toluene decomposition efficiency was increased (Authors)

  16. Preliminary experiments on wastes degradation by thermal plasma

    International Nuclear Information System (INIS)

    Cota S, G.; Pacheco S, J.; Segovia R, A.; Pena E, R.; Merlo S, L.

    1996-01-01

    This work presents the fundamental aspects involved in the installation and start up of an experimental equipment for the hazardous wastes degradation using the thermal plasma technology. It is mentioned about the form in which the thermal plasma is generated and the characteristics that its make to be an appropriate technology for the hazardous wastes degradation. Just as the installed structures for to realize the experiments and results of the first studies on degradation, using nylon as problem sample. (Author)

  17. Development of twin cannons of thermal plasma

    International Nuclear Information System (INIS)

    Pena E, R.

    1996-01-01

    Today several service and transformation industries that generate hazardous wastes must implement programs in order to fulfill with requirements established by the present standardization. This problem is solved here for proposing the design and construction of a thermal plasma transferred torch with double cannon which is generated by an electric arc with a capacity of 50 k W, a regulable gas flow from 0-50 lt./min and thermal yield higher than 85 %. This equipment would be capable for degradating industrial and hospital wastes. (Author)

  18. Treatment of mixed wastes by thermal plasma discharges

    International Nuclear Information System (INIS)

    Diaz A, L.V.

    2007-01-01

    The present study has as purpose to apply the technology of thermal plasma in the destruction of certain type of waste generated in the ININ. As first instance, origin, classification and disposition of the radioactive waste generated in the ININ is identified. Once identified the waste, the waste to treat is determined based on: the easiness of treating him with plasma, classification and importance. Later on, a substance or compound settles down (sample model) that serves as indicative of the waste for its physical-chemical characteristics, this is made because in the Thermal Plasma Applications Laboratory is not had the license to work with radioactive material. The sample model and the material to form the vitreous matrix are characterized before and after the treatment in order to evaluating their degradation and vitrification. During the treatment by means of the thermal plasma, the appropriate conditions are determined for the degradation and vitrification of the waste. Also, it is carried out an energy balance in the system to know the capacity to fuse the material depending the transfer of existent heat between the plasma and the material to treat. Obtaining favorable results, it thought about to climb in the project and by this way to help to solve one of the environmental problems in Mexico, as they are it the mixed wastes. (Author)

  19. Foundations of High-Pressure Thermal Plasmas

    Science.gov (United States)

    Murphy, Anthony B.; Uhrlandt, Dirk

    2018-06-01

    An introduction to the main methods used to produce, model and measure thermal plasmas is provided, with emphasis on the differences between thermal plasmas and other types of processing plasmas. The critical properties of thermal plasmas are explained in physical terms and their importance in different applications is considered. The characteristics, and advantages and disadvantages, of the different main types of thermal plasmas (transferred and non-transferred arcs, radio-frequency inductively-coupled plasmas and microwave plasmas) are discussed. The methods by which flow is stabilized in arc plasmas are considered. The important concept of local thermodynamic equilibrium (LTE) is explained, leading into a discussion of the importance of thermophysical properties, and their calculation in LTE and two-temperature plasmas. The standard equations for modelling thermal plasmas are presented and contrasted with those used for non-equilibrium plasmas. Treatments of mixed-gas and non-LTE plasmas are considered, as well as the sheath regions adjacent to electrodes. Finally, the main methods used for electrical, optical, spectroscopic and laser diagnostics of thermal plasmas are briefly introduced, with an emphasis on the required assumptions for their reliable implementation, and the specific requirements of thermal plasmas.

  20. Use of residual hydrocarbons treated by Thermal Plasma (recovery of energy by-products)

    International Nuclear Information System (INIS)

    Carreno B, J.A.; Pacheco S, J.O.; Ramos F, F.; Cruz A, A.; Duran G, M.

    2001-01-01

    The emergence of new technologies is getting greater importance for the control of pollution. One of them is the destruction of hazardous wastes treated by thermal plasma, which is of special interest for the efficient treatment of the hazardous wastes since the heat generated by thermal plasma is able to destroy the molecular bonds generating solids and gaseous products which do not represent danger for the human being and the environment. The thermal plasma is the suitable technology for treating a wide range of hazardous wastes, including the residual hydrocarbons from the refinement process of petroleum, plasma exceeds the barrier of 3000 Centigrade. The efficiency of the degradation of residues is greater than 99.99%. Toxic emissions are not generated to environment as SO 2 , NO x and CO 2 neither dioxins and furans by being a pyrolysis process. The use of hydrogen as fuel does not generate pollution to environment. (Author)

  1. Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

    International Nuclear Information System (INIS)

    Tanaka, Hiromasa; Mizuno, Masaaki; Toyokuni, Shinya; Maruyama, Shoichi; Kodera, Yasuhiro; Terasaki, Hiroko; Adachi, Tetsuo; Kato, Masashi; Kikkawa, Fumitaka; Hori, Masaru

    2015-01-01

    Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established

  2. Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Hiromasa [Institute of Innovation for Future Society, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Center for Advanced Medicine and Clinical Research, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Mizuno, Masaaki [Center for Advanced Medicine and Clinical Research, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Toyokuni, Shinya [Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Maruyama, Shoichi [Department of Nephrology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Kodera, Yasuhiro [Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Terasaki, Hiroko [Department of Ophthalmology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Adachi, Tetsuo [Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University, 501-1196 Gifu (Japan); Kato, Masashi [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Kikkawa, Fumitaka [Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Hori, Masaru [Institute of Innovation for Future Society, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2015-12-15

    Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established.

  3. Energy and costs scoping study for plasma pyrolysis thermal processing system

    International Nuclear Information System (INIS)

    Sherick, K.E.; Findley, J.E.

    1992-01-01

    The purpose of this study was to provide information in support of an investigation of thermal technologies as possible treatment process for buried wastes at the INEL. Material and energy balances and a cost estimate were generated for a representative plasma torch-based thermal waste treatment system operating in a pyrolysis mode. Two waste streams were selected which are representative of INEL buried wastes, large in volume, and difficult to treat by other technologies. These streams were a solidified nitrate sludge waste stream and a waste/soil mix of other buried waste components. The treatment scheme selected includes a main plasma chamber operating under pyrolyzing conditions; a plasma afterburner to provide additional residence time at high temperature to ensure complete destruction of hazardous organics; an off-gas treatment system; and a incinerator and stack to oxidize carbon monoxide to carbon dioxide and vent the clean, oxidized gases to atmosphere. The material balances generated provide materials flow and equipment duty information of sufficient accuracy to generate initial rough-order-of-magnitude (ROM) system capital and operating cost estimates for a representative plasma thermal processing system

  4. Suitability of thermal plasmas for large-area bacteria inactivation on temperature-sensitive surfaces – first results with Geobacillus stearothermophilus spores

    International Nuclear Information System (INIS)

    Szulc, M; Schein, S; Schaup, J; Zimmermann, S; Schein, J

    2017-01-01

    The application of thermal plasma for large-area bacteria inactivation on temperature-sensitive surfaces is not a common one. Nonetheless, there are thermal plasma generators which offer a high sheath homogeneity and have proven to be suitable for treatment of thermally sensitive materials in the past. To investigate the suitability of such plasmas, agar dishes plated with endospores of Geobacillus stearothermophilus have been treated with a long arc plasma generator called LARGE. The achieved results have been compared with a commercially available non-thermal plasma generator. A significant inactivation of the endospores could be observed only after 60 s of treatment with the thermal plasma source. This was not possible with the non-thermal generator. Moreover, no temperature damage or increase of the specimen could be detected. An attempt to determine the main agents responsible for the microbicidal effects have been made – the influence of plasma gas composition, discharge current and treatment time has been investigated. Significant improvements in the disinfection rates after adding small amounts of nitrogen to the plasma gas could be observed. A first discussion regarding the suitability of thermal plasmas for bacteria inactivation has been given. (paper)

  5. Role of thermo-physical properties on design and development of thermal plasma devices

    International Nuclear Information System (INIS)

    Ghorui, S.

    2014-01-01

    Thermal plasma devices find wide application in variety of technological areas like cutting, welding, spray coating, waste management, material processing, chemical reduction, nano-synthesis, novel material synthesis etc. Highly non-linear behavior of the plasma properties coupled with inherent instabilities, extremely high temperature, high gradients in thermal, and flow field, presence of thermal and chemical non-equilibrium make design and development of the plasma generating devices a challenging task as power levels of the devices increase

  6. A dc non-thermal atmospheric-pressure plasma microjet

    Science.gov (United States)

    Zhu, WeiDong; Lopez, Jose L.

    2012-06-01

    A direct current (dc), non-thermal, atmospheric-pressure plasma microjet is generated with helium/oxygen gas mixture as working gas. The electrical property is characterized as a function of the oxygen concentration and show distinctive regions of operation. Side-on images of the jet were taken to analyze the mode of operation as well as the jet length. A self-pulsed mode is observed before the transition of the discharge to normal glow mode. Optical emission spectroscopy is employed from both end-on and side-on along the jet to analyze the reactive species generated in the plasma. Line emissions from atomic oxygen (at 777.4 nm) and helium (at 706.5 nm) were studied with respect to the oxygen volume percentage in the working gas, flow rate and discharge current. Optical emission intensities of Cu and OH are found to depend heavily on the oxygen concentration in the working gas. Ozone concentration measured in a semi-confined zone in front of the plasma jet is found to be from tens to ˜120 ppm. The results presented here demonstrate potential pathways for the adjustment and tuning of various plasma parameters such as reactive species selectivity and quantities or even ultraviolet emission intensities manipulation in an atmospheric-pressure non-thermal plasma source. The possibilities of fine tuning these plasma species allows for enhanced applications in health and medical related areas.

  7. A dc non-thermal atmospheric-pressure plasma microjet

    International Nuclear Information System (INIS)

    Zhu Weidong; Lopez, Jose L

    2012-01-01

    A direct current (dc), non-thermal, atmospheric-pressure plasma microjet is generated with helium/oxygen gas mixture as working gas. The electrical property is characterized as a function of the oxygen concentration and show distinctive regions of operation. Side-on images of the jet were taken to analyze the mode of operation as well as the jet length. A self-pulsed mode is observed before the transition of the discharge to normal glow mode. Optical emission spectroscopy is employed from both end-on and side-on along the jet to analyze the reactive species generated in the plasma. Line emissions from atomic oxygen (at 777.4 nm) and helium (at 706.5 nm) were studied with respect to the oxygen volume percentage in the working gas, flow rate and discharge current. Optical emission intensities of Cu and OH are found to depend heavily on the oxygen concentration in the working gas. Ozone concentration measured in a semi-confined zone in front of the plasma jet is found to be from tens to ∼120 ppm. The results presented here demonstrate potential pathways for the adjustment and tuning of various plasma parameters such as reactive species selectivity and quantities or even ultraviolet emission intensities manipulation in an atmospheric-pressure non-thermal plasma source. The possibilities of fine tuning these plasma species allows for enhanced applications in health and medical related areas. (paper)

  8. Development of twin cannons of thermal plasma; Desarrollo de canones gemelos de plasma termico.

    Energy Technology Data Exchange (ETDEWEB)

    Pena E, R [Instituto Nacional de Investigaciones Nucleares, Mexico D.F. (Mexico)

    1997-12-31

    Today several service and transformation industries that generate hazardous wastes must implement programs in order to fulfill with requirements established by the present standardization. This problem is solved here for proposing the design and construction of a thermal plasma transferred torch with double cannon which is generated by an electric arc with a capacity of 50 k W, a regulable gas flow from 0-50 lt./min and thermal yield higher than 85 %. This equipment would be capable for degradating industrial and hospital wastes. (Author).

  9. Electron thermal capacity in plasma generated at cavitation bubble collapse in D-acetone

    International Nuclear Information System (INIS)

    Kostenko, B.F.; Pribis, J.

    2004-01-01

    The latest experimental data on nuclear reaction product registration at cavitation bubble collapse in deuterated acetone (C 3 D 6 O) still argue in favour of existence of a new possibility to realize the thermonuclear synthesis. Theoretical description based on numerical solution of simultaneous conservation equations for gaseous and liquid phases also confirms this possibility, although it requires further more precise definitions. In particular, description of electron degrees of freedom in dense nonequilibrium plasma generated at the final stage of bubble collapse need specification. Calculations of electron thermal capacity in the deuterated acetone multiple ionization region at electron temperatures T e ≅ 10 4 K and above and compression range ρ/ρ 0 ≅ 1 - 100 have been fulfilled on the basis of direct numerical solution of equation for chemical potential. (author)

  10. Physical phenomena in a low-temperature non-equilibrium plasma and in MHD generators with non-equilibrium conductivity

    International Nuclear Information System (INIS)

    Velikhov, E.P.; Golubev, V.S.; Dykhne, A.M.

    1976-01-01

    The paper assesses the position in 1975 of theoretical and experimental work on the physics of a magnetohydrodynamic generator with non-equilibrium plasma conductivity. This research started at the beginning of the 1960s; as work on the properties of thermally non-equilibrium plasma in magnetic fields and also in MHD generator ducts progressed, a number of phenomena were discovered and investigated that had either been unknown in plasma physics or had remained uninvestigated until that time: ionization instability and ionization turbulence of plasma in a magnetic field, acoustic instability of a plasma with anisotropic conductivity, the non-equilibrium ionization wave and the energy balance of a non-equilibrium plasma. At the same time, it was discovered what physical requirements an MHD generator with non-equilibrium conductivity must satisfy to achieve high efficiency in converting the thermal or kinetic energy of the gas flow into electric energy. The experiments on MHD power generation with thermally non-equilibrium plasma carried out up to 1975 indicated that it should be possible to achieve conversion efficiencies of up to 20-30%. (author)

  11. Electrical conductivity of the thermal dusty plasma under the conditions of a hybrid plasma environment simulation facility

    Science.gov (United States)

    Zhukhovitskii, Dmitry I.; Petrov, Oleg F.; Hyde, Truell W.; Herdrich, Georg; Laufer, Rene; Dropmann, Michael; Matthews, Lorin S.

    2015-05-01

    We discuss the inductively heated plasma generator (IPG) facility in application to the generation of the thermal dusty plasma formed by the positively charged dust particles and the electrons emitted by them. We develop a theoretical model for the calculation of plasma electrical conductivity under typical conditions of the IPG. We show that the electrical conductivity of dusty plasma is defined by collisions with the neutral gas molecules and by the electron number density. The latter is calculated in the approximations of an ideal and strongly coupled particle system and in the regime of weak and strong screening of the particle charge. The maximum attainable electron number density and corresponding maximum plasma electrical conductivity prove to be independent of the particle emissivity. Analysis of available experiments is performed, in particular, of our recent experiment with plasma formed by the combustion products of a propane-air mixture and the CeO2 particles injected into it. A good correlation between the theory and experimental data points to the adequacy of our approach. Our main conclusion is that a level of the electrical conductivity due to the thermal ionization of the dust particles is sufficiently high to compete with that of the potassium-doped plasmas.

  12. Super-Gaussian transport theory and the field-generating thermal instability in laser–plasmas

    International Nuclear Information System (INIS)

    Bissell, J J; Ridgers, C P; Kingham, R J

    2013-01-01

    Inverse bremsstrahlung (IB) heating is known to distort the electron distribution function in laser–plasmas from a Gaussian towards a super-Gaussian, thereby modifying the equations of classical transport theory (Ridgers et al 2008 Phys. Plasmas 15 092311). Here we explore these modified equations, demonstrating that super-Gaussian effects both suppress traditional transport processes, while simultaneously introducing new effects, such as isothermal (anomalous Nernst) magnetic field advection up gradients in the electron number density n e , which we associate with a novel heat-flow q n ∝∇n e . Suppression of classical phenomena is shown to be most pronounced in the limit of low Hall-parameter χ, in which case the Nernst effect is reduced by a factor of five, the ∇T e × ∇n e field generation mechanism by ∼30% (where T e is the electron temperature), and the diffusive and Righi–Leduc heat-flows by ∼80 and ∼90% respectively. The new isothermal field advection phenomenon and associated density-gradient driven heat-flux q n are checked against kinetic simulation using the Vlasov–Fokker–Planck code impact, and interpreted in relation to the underlying super-Gaussian distribution through simplified kinetic analysis. Given such strong inhibition of transport at low χ, we consider the impact of IB on the seeding and evolution of magnetic fields (in otherwise un-magnetized conditions) by examining the well-known field-generating thermal instability in the light of super-Gaussian transport theory (Tidman and Shanny 1974 Phys. Fluids 12 1207). Estimates based on conditions in an inertial confinement fusion (ICF) hohlraum suggest that super-Gaussian effects can reduce the growth-rate of the instability by ≳80%. This result may be important for ICF experiments, since by increasing the strength of IB heating it would appear possible to inhibit the spontaneous generation of large magnetic fields. (paper)

  13. Super-Gaussian transport theory and the field-generating thermal instability in laser-plasmas

    Science.gov (United States)

    Bissell, J. J.; Ridgers, C. P.; Kingham, R. J.

    2013-02-01

    Inverse bremsstrahlung (IB) heating is known to distort the electron distribution function in laser-plasmas from a Gaussian towards a super-Gaussian, thereby modifying the equations of classical transport theory (Ridgers et al 2008 Phys. Plasmas 15 092311). Here we explore these modified equations, demonstrating that super-Gaussian effects both suppress traditional transport processes, while simultaneously introducing new effects, such as isothermal (anomalous Nernst) magnetic field advection up gradients in the electron number density ne, which we associate with a novel heat-flow qn∝∇ne. Suppression of classical phenomena is shown to be most pronounced in the limit of low Hall-parameter χ, in which case the Nernst effect is reduced by a factor of five, the ∇Te × ∇ne field generation mechanism by ˜30% (where Te is the electron temperature), and the diffusive and Righi-Leduc heat-flows by ˜80 and ˜90% respectively. The new isothermal field advection phenomenon and associated density-gradient driven heat-flux qn are checked against kinetic simulation using the Vlasov-Fokker-Planck code impact, and interpreted in relation to the underlying super-Gaussian distribution through simplified kinetic analysis. Given such strong inhibition of transport at low χ, we consider the impact of IB on the seeding and evolution of magnetic fields (in otherwise un-magnetized conditions) by examining the well-known field-generating thermal instability in the light of super-Gaussian transport theory (Tidman and Shanny 1974 Phys. Fluids 12 1207). Estimates based on conditions in an inertial confinement fusion (ICF) hohlraum suggest that super-Gaussian effects can reduce the growth-rate of the instability by ≳80%. This result may be important for ICF experiments, since by increasing the strength of IB heating it would appear possible to inhibit the spontaneous generation of large magnetic fields.

  14. Electron Thermal Capacity in Plasma Generated at Cavitation Bubble Collapse in D-acetone

    CERN Document Server

    Kostenko, B F

    2004-01-01

    The latest experimental data on nuclear reaction product registration at cavitation bubble collapse in deuterated acetone (C$_3$D$_6$O) still argue in favour of existence of a new possibility to realize the thermonuclear synthesis. Theoretical description based on numerical solution of simultaneous conservation equations for gaseous and liquid phases also confirms this possibility, although it requires further more precise definitions. In particular, description of electron degrees of freedom in very dense nonequilibrium plasma generated at the final stage of bubble collapse needs specification. In the present paper, calculations of electron thermal capacity in the deuterated acetone multiple ionization region at electron temperatures $T_e \\simeq 10^4 $ K and above and compression range $\\rho/\\rho_0 \\simeq 1 \\div 100$ have been fulfilled on the basis of direct numerical solution of equation for chemical potential.

  15. Monitoring system for thermal plasma

    International Nuclear Information System (INIS)

    Romero G, M.; Vilchis P, A.E.

    1999-01-01

    In the Thermal plasma applications laboratory it has been the degradation project of oils for isolation in transformers. These are a very hazardous residues and at this time in the country they are stored in metal barrels. It has been the intention to undergo the oils to plasma for degradate them to non-hazardous residues. The system behavior must be monitored to establish the thermal plasma behavior. (Author)

  16. Generator of the low-temperature heterogeneous plasma flow

    Science.gov (United States)

    Yusupov, D. I.; Gadzhiev, M. Kh; Tyuftyaev, A. S.; Chinnov, V. F.; Sargsyan, M. A.

    2018-01-01

    A generator of low-temperature dc plasma with an expanding channel of an output electrode for gas-thermal spraying was designed and constructed. The delivery of the sprayed powder into the cathode and anode arc-binding zones or into the plasma jet below the anode binding was realized. The electrophysical characteristics of both the plasma torch and the heterogeneous plasma flow with Al2O3 powder are studied. It is shown that the current-voltage characteristic (CVC) of a plasma torch depends on the gas flow rate. If the flow rate varies from 1 to 3 g/s, the falling CVC becomes gradually increasing. The speed and temperature of the sprayed powder are determined.

  17. Kinetic study on non-thermal volumetric plasma decay in the early afterglow of air discharge generated by a short pulse microwave or laser

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wei, E-mail: yangwei861212@126.com; Zhou, Qianhong; Dong, Zhiwei [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)

    2016-08-28

    This paper reports a kinetic study on non-thermal plasma decay in the early afterglow of air discharge generated by short pulse microwave or laser. A global self-consistent model is based on the particle balance of complex plasma chemistry, electron energy equation, and gas thermal balance equation. Electron-ion Coulomb collision is included in the steady state Boltzmann equation solver to accurately describe the electron mobility and other transport coefficients. The model is used to simulate the afterglow of microsecond to nanosecond pulse microwave discharge in N{sub 2}, O{sub 2}, and air, as well as femtosecond laser filament discharge in dry and humid air. The simulated results for electron density decay are in quantitative agreement with the available measured ones. The evolution of plasma decay under an external electric field is also investigated, and the effect of gas heating is considered. The underlying mechanism of plasma density decay is unveiled through the above kinetic modeling.

  18. Industrial implementation of plasma deposition using the expanding thermal plasma technique

    NARCIS (Netherlands)

    Sanden, van de M.C.M.; Oever, van den P.J.; Creatore, M.; Schaepkens, M.; Miebach, T.; Iacovangelo, C.D.; Bosch, R.C.M.; Bijker, M.D.; Evers, M.F.J.; Schram, D.C.; Kessels, W.M.M.

    2004-01-01

    Two successful industrial implementations of the expanding thermal plasma setup, a novel plasma source, obtaining high deposition rate are discussed. The Ar/O2/hexamethyldisiloxane and Ar/O2/octamethyl-cyclosiloxane-fed expanding thermal plasma setup is used to deposit scratch resistant silicone

  19. The structure and thermal properties of plasma-sprayed beryllium for the International Thermonuclear Experimental Reactor (ITER)

    International Nuclear Information System (INIS)

    Castro, R.G.; Bartlett, A.; Elliott, K.E.; Hollis, K.J.

    1996-01-01

    Plasma spraying is being studied for in situ repair of damaged Be and W plasma facing surfaces for ITER, the next generation magnetic fusion energy device, and is also being considered for fabricating Be and W plasma-facing components for the first wall of ITER. Investigators at LANL's Beryllium Atomization and Thermal Spray Facility have concentrated on investigating the structure-property relation between as-deposited microstructures of plasma sprayed Be coatings and resulting thermal properties. In this study, the effect of initial substrate temperature on resulting thermal diffusivity of Be coatings and the thermal diffusivity at the coating/Be substrate interface (interface thermal resistance) was investigated. Results show that initial Be substrate temperatures above 600 C can improve the thermal diffusivity of the Be coatings and minimize any thermal resistance at the interface between the Be coating and Be substrate

  20. Non-thermal plasmas for non-catalytic and catalytic VOC abatement

    International Nuclear Information System (INIS)

    Vandenbroucke, Arne M.; Morent, Rino; De Geyter, Nathalie; Leys, Christophe

    2011-01-01

    Highlights: → We review the current status of catalytic and non-catalytic VOC abatement based on a vast number of research papers. → The underlying mechanisms of plasma-catalysis for VOC abatement are discussed. → Critical process parameters that determine the influent are discussed and compared. - Abstract: This paper reviews recent achievements and the current status of non-thermal plasma (NTP) technology for the abatement of volatile organic compounds (VOCs). Many reactor configurations have been developed to generate a NTP at atmospheric pressure. Therefore in this review article, the principles of generating NTPs are outlined. Further on, this paper is divided in two equally important parts: plasma-alone and plasma-catalytic systems. Combination of NTP with heterogeneous catalysis has attracted increased attention in order to overcome the weaknesses of plasma-alone systems. An overview is given of the present understanding of the mechanisms involved in plasma-catalytic processes. In both parts (plasma-alone systems and plasma-catalysis), literature on the abatement of VOCs is reviewed in close detail. Special attention is given to the influence of critical process parameters on the removal process.

  1. An Explorative Study to Use DBD Plasma Generation for Aircraft Icing Mitigation

    Science.gov (United States)

    Hu, Hui; Zhou, Wenwu; Liu, Yang; Kolbakir, Cem

    2017-11-01

    An explorative investigation was performed to demonstrate the feasibility of utilizing thermal effect induced by Dielectric-Barrier-Discharge (DBD) plasma generation for aircraft icing mitigation. The experimental study was performed in an Icing Research Tunnel available at Iowa State University (i.e., ISU-IRT). A NACA0012 airfoil/wing model embedded with DBD plasma actuators was installed in ISU-IRT under typical glaze icing conditions pertinent to aircraft inflight icing phenomena. While a high-speed imaging system was used to record the dynamic ice accretion process over the airfoil surface for the test cases with and without switching on the DBD plasma actuators, an infrared (IR) thermal imaging system was utilized to map the corresponding temperature distributions to quantify the unsteady heat transfer and phase changing process over the airfoil surface. The thermal effect induced by DBD plasma generation was demonstrated to be able to keep the airfoil surface staying free of ice during the entire ice accretion experiment. The measured quantitative surface temperature distributions were correlated with the acquired images of the dynamic ice accretion and water runback processes to elucidate the underlying physics. National Science Foundation CBET-1064196 and CBET-1435590.

  2. Water-stabilized plasma generators

    Czech Academy of Sciences Publication Activity Database

    Hrabovský, Milan

    1998-01-01

    Roč. 70, č. 6 (1998), s. 1157-1162 ISSN 0033-4545 R&D Projects: GA ČR GA102/95/0592; GA ČR GV106/96/K245 Institutional research plan: CEZ:AV0Z2043910 Keywords : thermal plasma, plasma torch, water-stabilized plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.677, year: 1998

  3. EXPERIMENTAL CHARACTERIZATION OF A MAGNETOHYDRODYNAMIC POWER GENERATOR UNDER DC ARC PLASMA

    Directory of Open Access Journals (Sweden)

    Ayokunle Oluwaseun Ayeleso

    2018-02-01

    Full Text Available The generation of electric power through the conventional systems (thermal and hydroelectric is no longer sufficient to meet the increasing industrial and commercial usage. Therefore, an alternative energy conversion system is currently being sought. The aim of the presented study is to develop a direct energy conversion system (Magnetohydrodynamics, MHD generator to generate electric power using plasma. Additionally, the generator electric response is investigated based on the Faraday’s principle of electromagnetism and fluid dynamics. For this purpose, a rectangular MHD generator prototype with segmented electrodes was constructed and subjected to continuous plasma from a DC arc source at test facilities available in the Western Cape region (South Africa. Subsequently, the terminal voltages at the middle-electrodes were measured one after another across 1, 100 and 470 Ω load resistors. In all experiments, the absolute time-averages of the measured terminal voltage across each load resistor were similar, which indicates a generation of power. The maximum power of the order 0.203mW was obtained when 1 Ω resistor was connected to the middle-electrodes. Conclusively, these results validate the measurement approach of the MHD generator with segmented electrodes and could be used to design a large MHD unit that can be incorporated to the existing conventional thermal plant to improve their cyclic thermal efficiency.

  4. Waves generated in the plasma plume of helicon magnetic nozzle

    International Nuclear Information System (INIS)

    Singh, Nagendra; Rao, Sathyanarayan; Ranganath, Praveen

    2013-01-01

    Experimental measurements have shown that the plasma plume created in a helicon plasma device contains a conical structure in the plasma density and a U-shaped double layer (US-DL) tightly confined near the throat where plasma begins to expand from the source. Recently reported two-dimensional particle-in-cell simulations verified these density and US-DL features of the plasma plume. Simulations also showed that the plasma in the plume develops non-thermal feature consisting of radial ion beams with large densities near the conical surface of the density structure. The plasma waves that are generated by the radial ion beams affecting the structure of the plasma plume are studied here. We find that most intense waves persist in the high-density regions of the conical density structure, where the transversely accelerated ions in the radial electric fields in the plume are reflected setting up counter-streaming. The waves generated are primarily ion Bernstein modes. The nonlinear evolution of the waves leads to magnetic field-aligned striations in the fields and the plasma near the conical surface of the density structure.

  5. Waves generated in the plasma plume of helicon magnetic nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Nagendra; Rao, Sathyanarayan; Ranganath, Praveen [Department of Electrical and Computer Engineering, University of Alabama, Huntsville, Alabama 35899 (United States)

    2013-03-15

    Experimental measurements have shown that the plasma plume created in a helicon plasma device contains a conical structure in the plasma density and a U-shaped double layer (US-DL) tightly confined near the throat where plasma begins to expand from the source. Recently reported two-dimensional particle-in-cell simulations verified these density and US-DL features of the plasma plume. Simulations also showed that the plasma in the plume develops non-thermal feature consisting of radial ion beams with large densities near the conical surface of the density structure. The plasma waves that are generated by the radial ion beams affecting the structure of the plasma plume are studied here. We find that most intense waves persist in the high-density regions of the conical density structure, where the transversely accelerated ions in the radial electric fields in the plume are reflected setting up counter-streaming. The waves generated are primarily ion Bernstein modes. The nonlinear evolution of the waves leads to magnetic field-aligned striations in the fields and the plasma near the conical surface of the density structure.

  6. Advanced oxidation technology for H2S odor gas using non-thermal plasma

    Science.gov (United States)

    Tao, ZHU; Ruonan, WANG; Wenjing, BIAN; Yang, CHEN; Weidong, JING

    2018-05-01

    Non-thermal plasma technology is a new type of odor treatment processing. We deal with H2S from waste gas emission using non-thermal plasma generated by dielectric barrier discharge. On the basis of two criteria, removal efficiency and absolute removal amount, we deeply investigate the changes in electrical parameters and process parameters, and the reaction process of the influence of ozone on H2S gas removal. The experimental results show that H2S removal efficiency is proportional to the voltage, frequency, power, residence time and energy efficiency, while it is inversely proportional to the initial concentration of H2S gas, and ozone concentration. This study lays the foundations of non-thermal plasma technology for further commercial application.

  7. Non-thermal plasma ethanol reforming in bubbles immersed in liquids

    International Nuclear Information System (INIS)

    Levko, Dmitry; Sharma, Ashish; Raja, Laxminarayan L

    2017-01-01

    Ethanol reforming in non-thermal plasma generated in atmospheric-pressure argon bubbles immersed in liquid ethanol/water solution is studied using a self-consistent multi-species fluid model. The influence of the dielectric constant of the liquid on the plasma dynamics and its effect on the generation of active species is analyzed. Several modes of discharge are obtained for large liquid dielectric constant. In these modes, we obtain either an axial streamer or a combination of two simultaneous streamers propagating along the bubble axis and near the liquid wall. The influence of these modes on the production of active species is also studied. The main reactions responsible for the generation of molecular hydrogen and light hydrocarbon species are analyzed. A possible mechanism of hydrogen generation in liquid phase is discussed. (paper)

  8. Study of non inductive current generation in a plasma

    International Nuclear Information System (INIS)

    Rax, J.M.

    1987-01-01

    The problem of non-thermal bremsstrahlung during lower hybrid current drive is considered. The proposed method shows the role of the Compton effects at low frequencies and allows us to establish the link between the emitted power and the absorbed power at high frequency. The non-thermal emission is considered as a kinematical mode conversion between the absorbed radio-frequency mode and the emitted X ray photons. The fast electrons diagnostics and the ways to reach the wave structure are shown. Kinetic and electromagnetic problems concerning current generation are described. The plasma properties and diagnostics in the case of a non inductive current generation are discussed [fr

  9. Beam-plasma instability in ion beam systems used in neutral beam generation

    International Nuclear Information System (INIS)

    Hooper, E.B. Jr.

    1977-02-01

    The beam-plasma instability is analyzed for the ion beams used for neutral beam generation. Both positive and negative ion beams are considered. Stability is predicted when the beam velocity is less than the electron thermal velocity; the only exception occurs when the electron density accompanying a negative ion beam is less than the ion density by nearly the ratio of electron to ion masses. For cases in which the beam velocity is greater than the electron thermal velocity, instability is predicted near the electron plasma frequency

  10. Electron current generated in a toroidal plasma on injection of high-energy neutrals

    International Nuclear Information System (INIS)

    Kolesnichenko, Ya.I.; Reznik, S.N.

    1981-01-01

    Problem of generation of electron current in toroidal plasma with a high-energy ion beam produced during neutral injection has been considered. The analysis was performed on the assumption that plasma is in the regime of rare collisions (banana regime) and ion beam velocity is considerably lower than thermal velocity of plasma ions. Formulae establishing the relation between beam current and electron current have been derived. It follows from them that toroidal affect considerably plasma current generated with the beam and under certain conditions result in changing this current direction in an area remoted from magne-- tic axis [ru

  11. Characterization of pulsed atmospheric-pressure plasma streams (PAPS) generated by a plasma gun

    Science.gov (United States)

    Robert, E.; Sarron, V.; Riès, D.; Dozias, S.; Vandamme, M.; Pouvesle, J.-M.

    2012-06-01

    An experimental study of atmospheric-pressure rare gas plasma propagation in a high-aspect-ratio capillary is reported. The plasma is generated with a plasma gun device based on a dielectric barrier discharge (DBD) reactor powered by either nanosecond or microsecond rise-time high-voltage pulses at single-shot to multi-kHz frequencies. The influence of the voltage waveform, pulse polarity, pulse repetition rate and capillary material have been studied using nanosecond intensified charge-coupled device imaging and plasma-front velocity measurements. The evolution of the plasma appearance during its propagation and the study of the role of the different experimental parameters lead us to suggest a new denomination of pulsed atmospheric-pressure plasma streams to describe all the plasma features, including the previously so-called plasma bullet. The unique properties of such non-thermal plasma launching in capillaries, far from the primary DBD plasma, are associated with a fast ionization wave travelling with velocity in the 107-108 cm s-1 range. Voltage pulse tailoring is shown to allow for a significant improvement of such plasma delivery. Thus, the plasma gun device affords unique opportunities in biomedical endoscopic applications.

  12. Characterization of pulsed atmospheric-pressure plasma streams (PAPS) generated by a plasma gun

    International Nuclear Information System (INIS)

    Robert, E; Sarron, V; Riès, D; Dozias, S; Vandamme, M; Pouvesle, J-M

    2012-01-01

    An experimental study of atmospheric-pressure rare gas plasma propagation in a high-aspect-ratio capillary is reported. The plasma is generated with a plasma gun device based on a dielectric barrier discharge (DBD) reactor powered by either nanosecond or microsecond rise-time high-voltage pulses at single-shot to multi-kHz frequencies. The influence of the voltage waveform, pulse polarity, pulse repetition rate and capillary material have been studied using nanosecond intensified charge-coupled device imaging and plasma-front velocity measurements. The evolution of the plasma appearance during its propagation and the study of the role of the different experimental parameters lead us to suggest a new denomination of pulsed atmospheric-pressure plasma streams to describe all the plasma features, including the previously so-called plasma bullet. The unique properties of such non-thermal plasma launching in capillaries, far from the primary DBD plasma, are associated with a fast ionization wave travelling with velocity in the 10 7 –10 8 cm s −1 range. Voltage pulse tailoring is shown to allow for a significant improvement of such plasma delivery. Thus, the plasma gun device affords unique opportunities in biomedical endoscopic applications. (paper)

  13. The conversion of the thermal energy of plasma in the SOL of tokamaks

    International Nuclear Information System (INIS)

    Nedospasov, A.V.; Nenova, N.V.

    2008-01-01

    When the plasma expands across the confining magnetic field, a part of its thermal energy is converted to electrical energy. In the SOL of tokamaks, the motion of the plasma across the field due to turbulent processes is accompanied by its departure along the open lines of the magnetic field. The conversion of thermal energy is taken into account in theoretical studies devoted to the physics of plasma in the SOL; however, this conversion is ignored in numerical models, for example, in B2-SOLPS4.0. This paper deals with thermal-to-electrical energy conversion in the SOL of tokamaks. It is demonstrated that the part of the thermal energy subjected to conversion to electrical energy forms an appreciable part of the total energy flowing in the SOL. In ITER, this fraction may be as high as 20-25%. The electrical energy generated in the SOL volume is liberated in the form of Joule heat in a relatively cold plasma in the vicinity of diverter plates or directly on these plates. (letter)

  14. Next Generation Thermal Barrier Coatings for the Gas Turbine Industry

    Science.gov (United States)

    Curry, Nicholas; Markocsan, Nicolaie; Li, Xin-Hai; Tricoire, Aurélien; Dorfman, Mitch

    2011-01-01

    The aim of this study is to develop the next generation of production ready air plasma sprayed thermal barrier coating with a low conductivity and long lifetime. A number of coating architectures were produced using commercially available plasma spray guns. Modifications were made to powder chemistry, including high purity powders, dysprosia stabilized zirconia powders, and powders containing porosity formers. Agglomerated & sintered and homogenized oven spheroidized powder morphologies were used to attain beneficial microstructures. Dual layer coatings were produced using the two powders. Laser flash technique was used to evaluate the thermal conductivity of the coating systems from room temperature to 1200 °C. Tests were performed on as-sprayed samples and samples were heat treated for 100 h at 1150 °C. Thermal conductivity results were correlated to the coating microstructure using image analysis of porosity and cracks. The results show the influence of beneficial porosity on reducing the thermal conductivity of the produced coatings.

  15. Monitoring system for thermal plasma; Sistema de monitoreo para plasma termico

    Energy Technology Data Exchange (ETDEWEB)

    Romero G, M.; Vilchis P, A.E. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1999-07-01

    In the Thermal plasma applications laboratory it has been the degradation project of oils for isolation in transformers. These are a very hazardous residues and at this time in the country they are stored in metal barrels. It has been the intention to undergo the oils to plasma for degradate them to non-hazardous residues. The system behavior must be monitored to establish the thermal plasma behavior. (Author)

  16. Richtmyer–Meshkov instability of a thermal interface in a two-fluid plasma

    KAUST Repository

    Bond, D.

    2017-11-03

    We computationally investigate the Richtmyer–Meshkov instability of a density interface with a single-mode perturbation in a two-fluid, ion–electron plasma with no initial magnetic field. Self-generated magnetic fields arise subsequently. We study the case where the density jump across the initial interface is due to a thermal discontinuity, and select plasma parameters for which two-fluid plasma effects are expected to be significant in order to elucidate how they alter the instability. The instability is driven via a Riemann problem generated precursor electron shock that impacts the density interface ahead of the ion shock. The resultant charge separation and motion generates electromagnetic fields that cause the electron shock to degenerate and periodically accelerate the electron and ion interfaces, driving Rayleigh–Taylor instability. This generates small-scale structures and substantially increases interfacial growth over the hydrodynamic case.

  17. Modeling of thermalization phenomena in coaxial plasma accelerators

    Science.gov (United States)

    Subramaniam, Vivek; Panneerchelvam, Premkumar; Raja, Laxminarayan L.

    2018-05-01

    Coaxial plasma accelerators are electromagnetic acceleration devices that employ a self-induced Lorentz force to produce collimated plasma jets with velocities ~50 km s‑1. The accelerator operation is characterized by the formation of an ionization/thermalization zone near gas inlet of the device that continually processes the incoming neutral gas into a highly ionized thermal plasma. In this paper, we present a 1D non-equilibrium plasma model to resolve the plasma formation and the electron-heavy species thermalization phenomena that take place in the thermalization zone. The non-equilibrium model is based on a self-consistent multi-species continuum description of the plasma with finite-rate chemistry. The thermalization zone is modelled by tracking a 1D gas-bit as it convects down the device with an initial gas pressure of 1 atm. The thermalization process occurs in two stages. The first is a plasma production stage, associated with a rapid increase in the charged species number densities facilitated by cathode surface electron emission and volumetric production processes. The production stage results in the formation of a two-temperature plasma with electron energies of ~2.5 eV in a low temperature background gas of ~300 K. The second, a temperature equilibration stage, is characterized by the energy transfer between the electrons and heavy species. The characteristic length scale for thermalization is found to be comparable to axial length of the accelerator thus putting into question the equilibrium magnetohydrodynamics assumption used in modeling coaxial accelerators.

  18. High duty factor plasma generator for CERN's Superconducting Proton Linac.

    Science.gov (United States)

    Lettry, J; Kronberger, M; Scrivens, R; Chaudet, E; Faircloth, D; Favre, G; Geisser, J-M; Küchler, D; Mathot, S; Midttun, O; Paoluzzi, M; Schmitzer, C; Steyaert, D

    2010-02-01

    CERN's Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN's PS-Booster. Its ion source is a noncesiated rf driven H(-) volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H(-) during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the Large Hadron Collider. It consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H(-) during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H(-) plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the required heat dissipation and maintains the original functionality. Materials with higher thermal conductivity are selected and, wherever possible, thermal barriers resulting from low pressure contacts are removed by brazing metals on insulators. The AlN plasma chamber cooling circuit is inspired from the approach chosen for the cesiated high duty factor rf H(-) source operating at SNS.

  19. Waste cell phone recycling by thermal plasma techniques

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, T.; Kunimoto, N.; Abe, S. [Chuo Univ., Bunkyo-Ku, Tokyo (Japan). Dept. of Electrical, Electronics, and Communication Engineering; Li, O.L.; Chang, J.S.; Ruj, B. [McMaster Univ., Hamilton, ON (Canada). Faculty of Engineering

    2010-07-01

    Due to the cost-effective nature of wireless networks, the number of cell phones used around the world has increased significantly. However, a major problem of this technology is the generation of a great deal of complex electronics wastes, such as cell phones. The typical average life of a cell phone is around 2 years. Therefore, inexpensive recycling techniques must be developed for valuable resources such as real metals and plastics used in cell phones. Thermal plasma has been used for many different waste treatments since it has the capability to detoxify waste by-products. This paper presented a preliminary investigation for cell phone recycling by a thermal plasma technology. Recyclable resource material was identified by neutron activation analyses. Then, the cell phone waste was first crashed and treated by Ar twin torch plasmas to remove the majority of organic materials. The paper described the experimental apparatus and results. It was concluded that styrene (C{sub 8}H{sub 8}) and benzene (C{sub 6}H{sub 6}O) may be two major by-products in on-line by-products gas. The molecule becomes a much heavier by-product gas after cooling down. 6 refs., 6 figs.

  20. 27.12 MHz plasma generation in supercritical carbon dioxide

    International Nuclear Information System (INIS)

    Kawashima, Ayato; Toyota, Hiromichi; Nomura, Shinfuku; Takemori, Toshihiko; Mukasa, Shinobu; Maehara, Tsunehiro; Yamashita, Hiroshi

    2007-01-01

    An experiment was conducted for generating high-frequency plasma in supercritical carbon dioxide; it is expected to have the potential for applications in various types of practical processes. It was successfully generated at 6-20 MPa using electrodes mounted in a supercritical cell with a gap of 1 mm. Emission spectra were then measured to investigate the physical properties of supercritical carbon dioxide plasma. The results indicated that while the emission spectra for carbon dioxide and carbon monoxide could be mainly obtained at a low pressure, the emission spectra for atomic oxygen could be obtained in the supercritical state, which increased with the pressure. The temperature of the plasma in supercritical state was estimated to be approximately 6000-7000 K on the assumption of local thermodynamic equilibrium and the calculation results of thermal equilibrium composition in this state showed the increase of atomic oxygen by the decomposition of CO 2

  1. Ignition phase and steady-state structures of a non-thermal air plasma

    CERN Document Server

    Lu Xin Pei

    2003-01-01

    An AC-driven, non-thermal, atmospheric pressure air plasma is generated within the gap separating a disc-shaped metal electrode and a water electrode. The ignition phase and the steady-state are studied by a high-speed CCD camera. It is found that the plasma always initiates at the surface of the water electrode. The plasma exhibits different structures depending on the polarity of the water electrode: when the water electrode plays the role of cathode, a relatively wide but visibly dim plasma column is generated. At the maximum driving voltage, the gas temperature is between 800 and 900 K, and the peak current is 67 mA; when the water electrode is anode, the plasma column narrows but increases its light emission. The gas temperature in this case is measured to be in the 1400-1500 K range, and the peak current is 81 mA.

  2. Thermal instability in a stratified plasma

    International Nuclear Information System (INIS)

    Hermanns, D.F.M.; Priest, E.R.

    1989-01-01

    The thermal instability mechansism has been studied in connection to observed coronal features, like, e.g. prominences or cool cores in loops. Although these features show a lot of structure, most studies concern the thermal instability in an uniform medium. In this paper, we investigate the thermal instability and the interaction between thermal modes and the slow magneto-acoustic subspectrum for a stratified plasma slab. We fomulate the relevant system of equations and give some straightforward properties of the linear spectrum of a non-uniform plasma slab, i.e. the existence of continuous parts in the spectrum. We present a numerical scheme with which we can investigate the linear spectrum for equilibrium states with stratification. The slow and thermal subspectra of a crude coronal model are given as a preliminary result. (author). 6 refs.; 1 fig

  3. Exogenous nitric oxide (NO) generated by NO-plasma treatment modulates osteoprogenitor cells early differentiation

    International Nuclear Information System (INIS)

    Elsaadany, Mostafa; Subramanian, Gayathri; Ayan, Halim; Yildirim-Ayan, Eda

    2015-01-01

    In this study, we investigated whether nitric oxide (NO) generated using a non-thermal plasma system can mediate osteoblastic differentiation of osteoprogenitor cells without creating toxicity. Our objective was to create an NO delivery mechanism using NO-dielectric barrier discharge (DBD) plasma that can generate and transport NO with controlled concentration to the area of interest to regulate osteoprogenitor cell activity. We built a non-thermal atmospheric pressure DBD plasma nozzle system based on our previously published design and similar designs in the literature. The electrical and spectral analyses demonstrated that N 2 dissociated into NO under typical DBD voltage–current characteristics. We treated osteoprogenitor cells (MC3T3-E1) using NO-plasma treatment system. Our results demonstrated that we could control NO concentration within cell culture media and could introduce NO into the intracellular space using NO-plasma treatment with various treatment times. We confirmed that NO-plasma treatment maintained cell viability and did not create any toxicity even with prolonged treatment durations. Finally, we demonstrated that NO-plasma treatment induced early osteogenic differentiation in the absence of pro-osteogenic growth factors/proteins. These findings suggest that through the NO-plasma treatment system we are able to generate and transport tissue-specific amounts of NO to an area of interest to mediate osteoprogenitor cell activity without subsequent toxicity. This opens up the possibility to develop DBD plasma-assisted tissue-specific NO delivery strategies for therapeutic intervention in the prevention and treatment of bone diseases. (paper)

  4. Monitoring non-thermal plasma processes for nanoparticle synthesis

    Science.gov (United States)

    Mangolini, Lorenzo

    2017-09-01

    Process characterization tools have played a crucial role in the investigation of dusty plasmas. The presence of dust in certain non-thermal plasma processes was first detected by laser light scattering measurements. Techniques like laser induced particle explosive evaporation and ion mass spectrometry have provided the experimental evidence necessary for the development of the theory of particle nucleation in silane-containing non-thermal plasmas. This review provides first a summary of these early efforts, and then discusses recent investigations using in situ characterization techniques to understand the interaction between nanoparticles and plasmas. The advancement of such monitoring techniques is necessary to fully develop the potential of non-thermal plasmas as unique materials synthesis and processing platforms. At the same time, the strong coupling between materials and plasma properties suggest that it is also necessary to advance techniques for the measurement of plasma properties while in presence of dust. Recent progress in this area will be discussed.

  5. Magnetic field approaches in dc thermal plasma modelling

    International Nuclear Information System (INIS)

    Freton, P; Gonzalez, J J; Masquere, M; Reichert, Frank

    2011-01-01

    The self-induced magnetic field has an important role in thermal plasma configurations generated by electric arcs as it generates velocity through Lorentz forces. In the models a good representation of the magnetic field is thus necessary. Several approaches exist to calculate the self-induced magnetic field such as the Maxwell-Ampere formulation, the vector potential approach combined with different kinds of boundary conditions or the Biot and Savart (B and S) formulation. The calculation of the self-induced magnetic field is alone a difficult problem and only few papers of the thermal plasma community speak on this subject. In this study different approaches with different boundary conditions are applied on two geometries to compare the methods and their limitations. The calculation time is also one of the criteria for the choice of the method and a compromise must be found between method precision and computation time. The study shows the importance of the current carrying path representation in the electrode on the deduced magnetic field. The best compromise consists of using the B and S formulation on the walls and/or edges of the calculation domain to determine the boundary conditions and to solve the vector potential in a 2D system. This approach provides results identical to those obtained using the B and S formulation over the entire domain but with a considerable decrease in calculation time.

  6. Plasma generator

    International Nuclear Information System (INIS)

    Omichi, Takeo; Yamanaka, Toshiyuki.

    1976-01-01

    Object: To recycle a coolant in a sealed hollow portion formed interiorly of a plasma limiter itself to thereby to cause direct contact between the coolant and the plasma limiter and increase of contact area therebetween to cool the plasma limiter. Structure: The heat resulting from plasma generated during operation and applied to the body of the plasma limiter is transmitted to the coolant, which recycles through an inlet and outlet pipe, an inlet and outlet nozzle and a hollow portion to hold the plasma limiter at a level less than a predetermined temperature. On the other hand, the heater wire is, at the time of emergency operation, energized to heat the plasma limiter, but this heat is transmitted to the limiter body to increase the temperature thereof. However, the coolant recycling the hollow portion comes into direct contact with the limiter body, and since the plasma limiter surround the hollow portion, the heat amount transmitted from the limiter body to the coolant increases to sufficiently cool the plasma limiter. (Yoshihara, H.)

  7. Investigation of non-thermal plasma effects on lung cancer cells within 3D collagen matrices

    Science.gov (United States)

    Karki, Surya B.; Thapa Gupta, Tripti; Yildirim-Ayan, Eda; Eisenmann, Kathryn M.; Ayan, Halim

    2017-08-01

    Recent breakthroughs in plasma medicine have identified a potential application for the non-thermal plasma in cancer therapy. Most studies on the effects of non-thermal plasma on cancer cells have used traditional two-dimensional (2D) monolayer cell culture. However, very few studies are conducted employing non-thermal plasma in animal models. Two dimensional models do not fully mimic the three-dimensional (3D) tumor microenvironment and animal models are expensive and time-consuming. Therefore, we used 3D collagen matrices that closely resemble the native geometry of cancer tissues and provide more physiologically relevant results than 2D models, while providing a more cost effective and efficient precursor to animal studies. We previously demonstrated a role for non-thermal plasma application in promoting apoptotic cell death and reducing the viability of A549 lung adenocarcinoma epithelial cells cultured upon 2D matrices. In this study, we wished to determine the efficacy of non-thermal plasma application in driving apoptotic cell death of A549 lung cancer cells encapsulated within a 3D collagen matrix. The percentage of apoptosis increased as treatment time increased and was time dependent. In addition, the anti-viability effect of plasma was demonstrated. Twenty-four hours post-plasma treatment, 38% and 99% of cell death occurred with shortest (15 s) and longest treatment time (120 s) respectively at the plasma-treated region. We found that plasma has a greater effect on the viability of A549 lung cancer cells on the superficial surface of 3D matrices and has diminishing effects as it penetrates the 3D matrix. We also identified the nitrogen and oxygen species generated by plasma and characterized their penetration in vertical and lateral directions within the 3D matrix from the center of the plasma-treated region. Therefore, the utility of non-thermal dielectric barrier discharge plasma in driving apoptosis and reducing the viability of lung cancer cells

  8. Investigation of non-thermal plasma effects on lung cancer cells within 3D collagen matrices

    International Nuclear Information System (INIS)

    Karki, Surya B; Gupta, Tripti Thapa; Yildirim-Ayan, Eda; Ayan, Halim; Eisenmann, Kathryn M

    2017-01-01

    Recent breakthroughs in plasma medicine have identified a potential application for the non-thermal plasma in cancer therapy. Most studies on the effects of non-thermal plasma on cancer cells have used traditional two-dimensional (2D) monolayer cell culture. However, very few studies are conducted employing non-thermal plasma in animal models. Two dimensional models do not fully mimic the three-dimensional (3D) tumor microenvironment and animal models are expensive and time-consuming. Therefore, we used 3D collagen matrices that closely resemble the native geometry of cancer tissues and provide more physiologically relevant results than 2D models, while providing a more cost effective and efficient precursor to animal studies. We previously demonstrated a role for non-thermal plasma application in promoting apoptotic cell death and reducing the viability of A549 lung adenocarcinoma epithelial cells cultured upon 2D matrices. In this study, we wished to determine the efficacy of non-thermal plasma application in driving apoptotic cell death of A549 lung cancer cells encapsulated within a 3D collagen matrix. The percentage of apoptosis increased as treatment time increased and was time dependent. In addition, the anti-viability effect of plasma was demonstrated. Twenty-four hours post-plasma treatment, 38% and 99% of cell death occurred with shortest (15 s) and longest treatment time (120 s) respectively at the plasma-treated region. We found that plasma has a greater effect on the viability of A549 lung cancer cells on the superficial surface of 3D matrices and has diminishing effects as it penetrates the 3D matrix. We also identified the nitrogen and oxygen species generated by plasma and characterized their penetration in vertical and lateral directions within the 3D matrix from the center of the plasma-treated region. Therefore, the utility of non-thermal dielectric barrier discharge plasma in driving apoptosis and reducing the viability of lung cancer cells

  9. On thermalization of electron-positron-photon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Siutsou, I. A., E-mail: siutsou@icranet.org [CAPES–ICRANet program, ICRANet–Rio, CBPF 22290-180, Rua Dr. Xavier Sigaud, 150, Urca, Rio de Janeiro, RJ (Brazil); Aksenov, A. G. [Institute for Computer-Aided Design, Russian Academy of Sciences 123056, 2nd Brestskaya st., 19/18, Moscow (Russian Federation); Vereshchagin, G. V. [ICRANet 65122, p.le della Republica, 10, Pescara (Italy)

    2015-12-17

    Recently a progress has been made in understanding thermalization mechanism of relativistic plasma starting from a non-equilibrium state. Relativistic Boltzmann equations were solved numerically for homogeneous isotropic plasma with collision integrals for two- and three-particle interactions calculated from the first principles by means of QED matrix elements. All particles were assumed to fulfill Boltzmann statistics. In this work we follow plasma thermalization by accounting for Bose enhancement and Pauli blocking in particle interactions. Our results show that particle in equilibrium reach Bose-Einstein distribution for photons, and Fermi-Dirac one for electrons, respectively.

  10. On thermalization of electron-positron-photon plasma

    Science.gov (United States)

    Siutsou, I. A.; Aksenov, A. G.; Vereshchagin, G. V.

    2015-12-01

    Recently a progress has been made in understanding thermalization mechanism of relativistic plasma starting from a non-equilibrium state. Relativistic Boltzmann equations were solved numerically for homogeneous isotropic plasma with collision integrals for two- and three-particle interactions calculated from the first principles by means of QED matrix elements. All particles were assumed to fulfill Boltzmann statistics. In this work we follow plasma thermalization by accounting for Bose enhancement and Pauli blocking in particle interactions. Our results show that particle in equilibrium reach Bose-Einstein distribution for photons, and Fermi-Dirac one for electrons, respectively.

  11. High resolution X-ray spectroscopy of thermal plasmas

    International Nuclear Information System (INIS)

    Canizares, C.R.

    1990-01-01

    This paper concentrates on reviewing highlights of the Focal Plane Crystal Spectrometer (FPCS) results on thermal plasmas, particularly supernova remnants (SNRs) and clusters of galaxies from the Einstein observatory. During Einstein's short but happy life, we made over 400 observations with the FPCS of 40 different objects. Three quarters of these were objects in which the emission was primarily from optically thin thermal plasma, primarily supernova remnants (SNRs) and clusters of galaxies. Thermal plasmas provide an excellent illustration of how spectral data, particularly high resolution spectral data, can be an important tool for probing the physical properties of astrophysical objects. (author)

  12. THERMODYNAMIC REASONS OF AGGLOMERATION OF DUST PARTICLES IN THE THERMAL DUSTY PLASMA

    Directory of Open Access Journals (Sweden)

    V.I.Vishnyakov

    2003-01-01

    Full Text Available The thermodynamic equilibrium of thermal dusty plasmas consisting of ionized gas (plasma and solid particles (dust grains, which interact with each other, is studied. The tendency of grains in dusty plasmas to agglomerate corresponds to the tendency of dusty plasmas to balanced states. When grains agglomerate, electrical perturbations generated by each grain concentrate inside the agglomerate. The plasma is perturbed only by the agglomerate's exterior surface. The greater number of possible states for electrons and ions in plasma depends on the volume of perturbation of grains. The fewer are the perturbations the greater is the amount of possible states for electrons and ions in plasma. If the grains collected from a distance smaller than 8 Debye lengths, the total volume of perturbations is minimized; the free energy of the plasma is also minimized.

  13. Stimulated Brillouin backscattering and magnetic field generation in laser-produced plasmas

    International Nuclear Information System (INIS)

    Bawa'aneh, M.S.

    1999-01-01

    This thesis is concerned with aspects of laser-plasma interactions related to fusion reactions; in particular thermoelectric magnetic field generation around a hole dug in plasma by intense laser beams, and stimulated Brillouin back scattering (SBBS) from plasmas containing hot spots. A hole, of the size of the laser focal spot, is dug in the plasma when illuminated by intense laser if the laser pressure exceeds the plasma thermal pressure. This hole is found to have steep, radial density gradients. My first concern arose from the prediction that magnetic fields might be generated around the hole-plasma interface in places where the steep density gradients overlap with the non-aligned temperature gradients. When a high-power laser beam is focused on a solid pellet, plasma is formed at the surface. In order to create conditions for thermonuclear reactions in the interior of the pellet, an effective deposition of the laser energy to thermal energy of the pellet via laser-plasma coupling is necessary. When light irradiates a plasma collective processes occur, which can either enhance or reduce the light absorption. For a better understanding of the fusion problem a knowledge of the nature of these collective processes and of the fraction of light reflected from the plasma modes is required. Local hot spots seen experimentally lead to higher gain levels of scattered light. These local temperature inhomogeneities could lead to non-equilibrium distributions, which result in a free energy leading to some interesting phenomena in plasma. In the second part of the thesis stimulated Brillouin back scattering from an ion acoustic mode in a hot spot is studied. Temperature inhomogeneities lead to an ion acoustic instability, and to higher levels of SBBS gain, which leads to lower thresholds for the same electron to ion temperature ratios. This could be the answer for the observed high levels of scattering from hot spots. (author)

  14. Simulations of planar non-thermal plasma assisted ignition at atmospheric pressure

    KAUST Repository

    Casey, Tiernan A.

    2016-10-21

    The opportunity for ignition assistance by a pulsed applied voltage is investigated in a canonical one-dimensional configuration. An incipient ignition kernel, formed by localized energy deposition into a lean mixture of methane and air at atmospheric pressure, is subjected to sub-breakdown electric fields (E/N ≈ 100 Td) by a DC potential applied across the domain, resulting in non-thermal behavior of the plasma formed during the discharge. A two-fluid approach is employed to couple thermal neutrals and ions to the non-thermal electrons. A two-temperature plasma mechanism describing gas phase combustion, excitation of neutral species, and high-energy electron kinetics is employed to account for non-thermal effects. Charged species transported from the ignition zone drift rapidly through the domain, augmenting the magnitude of the electric field in the fresh gas during the pulse through a dynamic-electrode effect, which results in an increase in the energy of the electrons in the fresh mixture with increasing time. Enhanced fuel and oxidizer decomposition due to electron impact dissociation and interaction with excited neutrals generate a pool of radicals, mostly O and H, in the fresh gas ahead of the flame\\'s preheat zone. In the configuration considered, the effect of the nanosecond pulse is to increase the mass of fuel burned at equivalent times relative to the unsupported ignition through enhanced radical generation, resulting in an increased heat release rate in the immediate aftermath of the pulse.

  15. Non-thermal plasma mills bacteria: Scanning electron microscopy observations

    International Nuclear Information System (INIS)

    Lunov, O.; Churpita, O.; Zablotskii, V.; Jäger, A.; Dejneka, A.; Deyneka, I. G.; Meshkovskii, I. K.; Syková, E.; Kubinová, Š.

    2015-01-01

    Non-thermal plasmas hold great promise for a variety of biomedical applications. To ensure safe clinical application of plasma, a rigorous analysis of plasma-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal plasma remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric plasma on Gram-positive and Gram-negative bacteria. Using scanning electron microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium plasma. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin–stained rat skin sections from plasma–treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal plasma irradiation. Our findings disclose how helium plasma destroys bacteria and demonstrates the safe use of plasma treatment for MSCs and skin cells, highlighting the favorability of plasma applications for chronic wound therapy

  16. Non-thermal plasma induces mitochondria-mediated apoptotic signaling pathway via ROS generation in HeLa cells.

    Science.gov (United States)

    Li, Wei; Yu, K N; Ma, Jie; Shen, Jie; Cheng, Cheng; Zhou, Fangjian; Cai, Zhiming; Han, Wei

    2017-11-01

    Non-thermal plasma (NTP) has been proposed as a novel therapeutic method for anticancer treatment. Although increasing evidence suggests that NTP selectively induces apoptosis in some types of tumor cells, the molecular mechanisms underlying this phenomenon remain unclear. In this study, we further investigated possible molecular mechanisms for NTP-induced apoptosis of HeLa cells. The results showed that NTP exposure significantly inhibited the growth and viability of HeLa cells. Morphological observation and flow cytometry analysis demonstrated that NTP exposure induced HeLa cell apoptosis. NTP exposure also activated caspase-9 and caspase-3, which subsequently cleaved poly (ADP- ribose) polymerase. Furthermore, NTP exposure suppressed Bcl-2 expression, enhanced Bax expression and translocation to mitochondria, activated mitochondria-mediated apoptotic pathway, followed by the release of cytochrome c. Further studies showed that NTP treatment led to ROS generation, whereas blockade of ROS generation by N-acetyl-l-cysteine (NAC, ROS scavengers) significantly prevented NTP-induced mitochondrial alteration and subsequent apoptosis of HeLa cells via suppressing Bax translocation, cytochrome c and caspase-3 activation. Taken together, our results indicated that NTP exposure induced mitochondria-mediated intrinsic apoptosis of HeLa cells was activated by ROS generation. These findings provide insights to the therapeutic potential and clinical research of NTP as a novel tool in cervical cancer treatment. Copyright © 2017. Published by Elsevier Inc.

  17. Synthesis of Ni2B nanoparticles by RF thermal plasma for fuel cell catalyst

    International Nuclear Information System (INIS)

    Cheng, Y; Tanaka, M; Watanabe, T; Choi, S Y; Shin, M S; Lee, K H

    2014-01-01

    The catalyst of Ni 2 B nanoparticles was successfully prepared using nickel and boron as precursors with the quenching gas in radio frequency thermal plasmas. The generating of Ni 2 B needs adequate reaction temperature and boron content in precursors. The quenching gas is beneficial for the synthesis of Ni 2 B in RF thermal plasma. The effect of quenching rate, powder feed rate and boron content in feeding powders on the synthesis of nickel boride nanoparticles was studied in this research. The high mass fraction of 28 % of Ni 2 B nanoparticles can be generated at the fixed initial composition of Ni:B = 2:3. Quenching gas is necessary in the synthesis of Ni 2 B nanoaprticles. In addition, the mass fraction of Ni 2 B increases with the increase of quenching gas flow rate and powder feed rate

  18. Implosive Thermal Plasma Source for Energy Conversion

    Czech Academy of Sciences Publication Activity Database

    Šonský, Jiří; Tesař, Václav; Gruber, Jan; Mašláni, Alan

    2017-01-01

    Roč. 4, č. 1 (2017), s. 87-90 ISSN 2336-2626 Institutional support: RVO:61388998 ; RVO:61389021 Keywords : implosion * thermal plasma * detonation wave Subject RIV: BL - Plasma and Gas Discharge Physics; BL - Plasma and Gas Discharge Physics (UFP-V) OBOR OECD: Fluids and plasma physics (including surface physics); Fluids and plasma physics (including surface physics) (UFP-V) https://ppt.fel.cvut.cz/ppt2017.html#number1

  19. Non-thermal plasma instabilities induced by deformation of the electron energy distribution function

    Science.gov (United States)

    Dyatko, N. A.; Kochetov, I. V.; Napartovich, A. P.

    2014-08-01

    Non-thermal plasma is a key component in gas lasers, microelectronics, medical applications, waste gas cleaners, ozone generators, plasma igniters, flame holders, flow control in high-speed aerodynamics and others. A specific feature of non-thermal plasma is its high sensitivity to variations in governing parameters (gas composition, pressure, pulse duration, E/N parameter). This sensitivity is due to complex deformations of the electron energy distribution function (EEDF) shape induced by variations in electric field strength, electron and ion number densities and gas excitation degree. Particular attention in this article is paid to mechanisms of instabilities based on non-linearity of plasma properties for specific conditions: gas composition, steady-state and decaying plasma produced by the electron beam, or by an electric current pulse. The following effects are analyzed: the negative differential electron conductivity; the absolute negative electron mobility; the stepwise changes of plasma properties induced by the EEDF bi-stability; thermo-current instability and the constriction of the glow discharge column in rare gases. Some of these effects were observed experimentally and some of them were theoretically predicted and still wait for experimental confirmation.

  20. Hydrogen production by thermal water splitting using a thermal plasma

    International Nuclear Information System (INIS)

    Boudesocque, N.; Lafon, C.; Girold, C.; Vandensteendam, C.; Baronnet, J.M.

    2006-01-01

    CEA has been working for more than 10 years in plasma technologies devoted to waste treatment: incineration, vitrification, gases and liquid treatment. Based on this experience, CEA experiments since several years an innovative route for hydrogen production by thermal water splitting, using a plasma as heat source. This new approach could be considered as an alternative to electrolysis for massive hydrogen production from water and electricity. This paper presents a brief state of the art of water thermal plasmas, showing the temperatures and quench velocity ranges technologically achievable today. Thermodynamic properties of a water plasma are presented and discussed. A kinetic computational model is presented, describing the behavior of splitted products during the quench in a plasma plume for various parameters, such as the quench rate. The model results are compared to gas analysis in the plasma plume obtained with in-situ sampling probe. The plasma composition measurements are issued from an Optical Emission Spectroscopic method (OES). The prediction of 30 % H 2 recovery with a 108 K.s -1 quench rate has been verified. A second experimentation has been performed: mass gas analysis, flowrate measurement and OES to study the 'behavior' and species in underwater electrical arc stricken between graphite electrodes. With this quench, a synthesis gas was produced with a content 55 % of hydrogen. (authors)

  1. Beam-generated plasmas for processing applications

    Science.gov (United States)

    Meger, R. A.; Blackwell, D. D.; Fernsler, R. F.; Lampe, M.; Leonhardt, D.; Manheimer, W. M.; Murphy, D. P.; Walton, S. G.

    2001-05-01

    The use of moderate energy electron beams (e-beams) to generate plasma can provide greater control and larger area than existing techniques for processing applications. Kilovolt energy electrons have the ability to efficiently ionize low pressure neutral gas nearly independent of composition. This results in a low-temperature, high-density plasma of nearly controllable composition generated in the beam channel. By confining the electron beam magnetically the plasma generation region can be designated independent of surrounding structures. Particle fluxes to surfaces can then be controlled by the beam and gas parameters, system geometry, and the externally applied rf bias. The Large Area Plasma Processing System (LAPPS) utilizes a 1-5 kV, 2-10 mA/cm2 sheet beam of electrons to generate a 1011-1012cm-3 density, 1 eV electron temperature plasma. Plasma sheets of up to 60×60 cm2 area have been generated in a variety of molecular and atomic gases using both pulsed and cw e-beam sources. The theoretical basis for the plasma production and decay is presented along with experiments measuring the plasma density, temperature, and potential. Particle fluxes to nearby surfaces are measured along with the effects of radio frequency biasing. The LAPPS source is found to generate large-area plasmas suitable for materials processing.

  2. Plasma wave and second harmonic generation

    International Nuclear Information System (INIS)

    Sodha, M.S.; Sharma, J.K.; Tewari, D.P.; Sharma, R.P.; Kaushik, S.C.

    1978-01-01

    An investigation is made of a plasma wave at pump wave frequency and second harmonic generation caused by a self induced transverse inhomogeneity introduced by a Gaussian electromagnetic beam in a hot collisionless plasma. In the presence of a Gaussian beam the carriers get redistributed from the high field region to the low field region by ponderomative force and a transverse density gradient is established in the plasma. When the electric vector of the main beam is parallel to this density gradient, a plasma wave at the pump wave frequency is generated. In addition to this the transverse intensity gradient of the electromagnetic wave also contributes significantly to the plasma wave generation. The power of the plasma wave exhibits a maximum and minimum with the power of the pump wave (at z = 0). The generated plasma wave interacts with the electromagnetic wave and leads to the generation of a second harmonic. Furthermore, if the initial power of the pump wave is more than the critical power for self-focusing, the beam gets self-focused and hence the generated plasma wave and second harmonic which depend upon the background electron concentration and power of the main beam also get accordingly modified. (author)

  3. Deviations from thermal equilibrium in plasmas

    International Nuclear Information System (INIS)

    Burm, K.T.A.L.

    2004-01-01

    A plasma system in local thermal equilibrium can usually be described with only two parameters. To describe deviations from equilibrium two extra parameters are needed. However, it will be shown that deviations from temperature equilibrium and deviations from Saha equilibrium depend on one another. As a result, non-equilibrium plasmas can be described with three parameters. This reduction in parameter space will ease the plasma describing effort enormously

  4. Enthalpy probe measurements and three-dimensional modelling on air plasma jets generated by a non-transferred plasma torch with hollow electrodes

    International Nuclear Information System (INIS)

    Kim, Keun Su; Park, Jin Myung; Choi, Sooseok; Kim, Jongin; Hong, Sang Hee

    2008-01-01

    Thermal flow characteristics of air plasma jets generated by a non-transferred plasma torch with hollow electrodes are experimentally and numerically investigated in order to provide more reliable scientific and technical information, which has been insufficient for their practical applications to material and environmental industries. In this work, a thermal plasma torch of hollow electrode type is first designed and fabricated, and similarity criteria for predicting operational conditions for the scale-up to high-power torches are derived from the arc voltage characteristics measured with various operating and geometry conditions of the torch. The thermal flow characteristics of air plasma jets ejected from the torch are measured by enthalpy probe diagnostics and turn out to have relatively low temperatures of around 3000-7000 K, but show features of other unique properties, such as high energy flux, broad high temperature region and long plasma jet with moderate axial velocity, which are promising for their applications to material syntheses and hazardous waste treatments. Such high enthalpy at a relatively low temperature of air thermal plasma compared with the argon one is due to the high thermal energy residing in the vibrational and rotational states and oxygen dissociation, besides the translational states in monatomic gases such as argon. It is expected that this high specific enthalpy of the air plasma will enable material and environmental industries to treat a large amount of precursors and waste materials effectively at a lower temperature for a longer residence time by the low plasma velocity. It is also found from the measurements that the turbulence intensity influenced by the size of the electrode diameter has a significant effect on the axial and radial profiles of plasma jet properties and that a longer plasma jet is more readily achievable with a larger electrode diameter reducing the turbulence intensity in the external region of the torch. In

  5. Electrical and thermal conductivities in dense plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Faussurier, G., E-mail: gerald.faussurier@cea.fr; Blancard, C.; Combis, P.; Videau, L. [CEA, DAM, DIF, F-91297 Arpajon (France)

    2014-09-15

    Expressions for the electrical and thermal conductivities in dense plasmas are derived combining the Chester-Thellung-Kubo-Greenwood approach and the Kramers approximation. The infrared divergence is removed assuming a Drude-like behaviour. An analytical expression is obtained for the Lorenz number that interpolates between the cold solid-state and the hot plasma phases. An expression for the electrical resistivity is proposed using the Ziman-Evans formula, from which the thermal conductivity can be deduced using the analytical expression for the Lorenz number. The present method can be used to estimate electrical and thermal conductivities of mixtures. Comparisons with experiment and quantum molecular dynamics simulations are done.

  6. The impact of transient thermal loads on beryllium as plasma facing material

    Energy Technology Data Exchange (ETDEWEB)

    Spilker, Benjamin Christof

    2017-01-24

    The rising global energy consumption requires a broad research and development approach in the field of energy technology. Besides renewables, nuclear fusion promises an efficient, CO{sub 2} free, no long-term radioactive waste producing, and safe energy source using only deuterium and lithium as primary resources, which are widely abundant. However, several technical challenges have to be overcome before a nuclear fusion power plant can be built. For this purpose, the experimental reactor ITER is currently under construction in France. ITER is intended to demonstrate the scientific and technological feasibility of net energy generation via nuclear fusion. The most heavily loaded components inside a fusion reactor, which are directly facing the fusion plasma, have to be armoured with well suited materials, which need to be able to withstand the high thermal and particle loads for an economically reasonable lifetime. For ITER, beryllium is chosen as plasma facing material for the largest fraction of the inner vacuum vessel, the so called first wall. Tungsten will be applied in the bottom region of the vacuum vessel, the so called divertor, which acts as the exhaust system of the machine. The choice of beryllium as plasma facing material was driven by its outstanding advantages, e.g. the low atomic number assures that eroded wall material does not strongly decrease the fusion plasma performance, while it combines a high thermal conductivity with low chemical sputtering characteristics. However, the relatively low melting temperature of beryllium of 1287 C comprises the risk of amour damage by melting during transient plasma events, such as edge localized modes or plasma disruptions. Even when mitigated, these events put tremendous power densities in the GW m{sup -2} range with durations in the ms scale onto the plasma facing materials. Hence, the performance of the ITER reference beryllium grade S-65 under transient thermal loads was studied within this work. Thereby

  7. The impact of transient thermal loads on beryllium as plasma facing material

    International Nuclear Information System (INIS)

    Spilker, Benjamin Christof

    2017-01-01

    The rising global energy consumption requires a broad research and development approach in the field of energy technology. Besides renewables, nuclear fusion promises an efficient, CO_2 free, no long-term radioactive waste producing, and safe energy source using only deuterium and lithium as primary resources, which are widely abundant. However, several technical challenges have to be overcome before a nuclear fusion power plant can be built. For this purpose, the experimental reactor ITER is currently under construction in France. ITER is intended to demonstrate the scientific and technological feasibility of net energy generation via nuclear fusion. The most heavily loaded components inside a fusion reactor, which are directly facing the fusion plasma, have to be armoured with well suited materials, which need to be able to withstand the high thermal and particle loads for an economically reasonable lifetime. For ITER, beryllium is chosen as plasma facing material for the largest fraction of the inner vacuum vessel, the so called first wall. Tungsten will be applied in the bottom region of the vacuum vessel, the so called divertor, which acts as the exhaust system of the machine. The choice of beryllium as plasma facing material was driven by its outstanding advantages, e.g. the low atomic number assures that eroded wall material does not strongly decrease the fusion plasma performance, while it combines a high thermal conductivity with low chemical sputtering characteristics. However, the relatively low melting temperature of beryllium of 1287 C comprises the risk of amour damage by melting during transient plasma events, such as edge localized modes or plasma disruptions. Even when mitigated, these events put tremendous power densities in the GW m"-"2 range with durations in the ms scale onto the plasma facing materials. Hence, the performance of the ITER reference beryllium grade S-65 under transient thermal loads was studied within this work. Thereby, the

  8. Formation of hydrophobic coating on glass surface using atmospheric pressure non-thermal plasma in ambient air

    International Nuclear Information System (INIS)

    Fang, Z; Qiu, Y; Kuffel, E

    2004-01-01

    Non-thermal plasmas under atmospheric pressure are of great interest in material surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of a glass surface for improving hydrophobicity using a non-thermal plasma generated by a dielectric barrier corona discharge (DBCD) with a needle array-to-plane electrode arrangement in atmospheric air is conducted, and the surface properties of the glass before and after the DBCD treatment are studied using contact angle measurement, surface resistance measurement and the wet flashover voltage test. The effects of the plasma dose (the product of average discharge power and treatment time) of DBCD on the surface modification are studied, and the mechanism of interaction between the plasma and glass surface is discussed. It is found that a layer of hydrophobic coating is formed on the glass surface through DBCD treatment, and the improvement of hydrophobicity depends on the plasma dose of the DBCD. It seems that there is an optimum plasma dose for the surface treatment. The test results of thermal ageing and chemical ageing show that the hydrophobic layer has quite stable characteristics

  9. Analysis of the expanding thermal argon-oxygen plasma gas phase

    International Nuclear Information System (INIS)

    Hest, M F A M van; Haartsen, J R; Weert, M H M van; Schram, D C; Sanden, M C M van de

    2003-01-01

    An expanding thermal argon plasma into which oxygen is injected has been analysed by means of Langmuir and Pitot probe measurements. Information is obtained on the ion density profile and the flow pattern in the downstream plasma. A combination of Langmuir and Pitot probe measurements provide information on the total ion flux generated by the plasma source (cascaded arc). It has been found that the ion diffusion is mainly determined by the background pressure in the expansion vessel and the arc current. The ion density is determined by the total power input into the plasma as well as the gas flow in the plasma source. There is an optimum in the power transfer used for ionization from plasma source to the feed gas. Interaction of oxygen with the plasma results in a decrease in the argon ion density and the plasma beam radius. The recirculation pattern of the downstream plasma has been investigated experimentally using the Pitot probe. Due to the low downstream pressure (10-30 Pa), the conventional compressible Pitot probe theory no longer applies. It is concluded that viscous effects start to play an important role at these low pressures and should be taken into account in the analysis of the Pitot probe measurements

  10. Preliminary degradation process study of infectious biological waste in a 5 k W thermal plasma equipment

    International Nuclear Information System (INIS)

    Xochihua S M, M.C.

    1997-01-01

    This work is a preliminary study of infectious biological waste degradation process by thermal plasma and was made in Thermal Plasma Applications Laboratory of Environmental Studies Department of the National Institute of Nuclear Research (ININ). Infectious biological waste degradation process is realized by using samples such polyethylene, cotton, glass, etc., but the present study scope is to analyze polyethylene degradation process with mass and energy balances involved. Degradation method is realized as follow: a polyethylene sample is put in an appropriated crucible localized inside a pyrolysis reactor chamber, the plasma jet is projected to the sample, by the pyrolysis phenomena the sample is degraded into its constitutive particles: carbon and hydrogen. Air was utilized as a recombination gas in order to obtain the higher percent of CO 2 if amount of O 2 is greater in the recombination gas, the CO generation is reduced. The effluent gases of exhaust pyrolysis reactor through are passed through a heat exchanger to get cooled gases, the temperature water used is 15 Centigrade degrees. Finally the gases was tried into absorption tower with water as an absorbent fluid. Thermal plasma degradation process is a very promising technology, but is necessary to develop engineering process area to avail all advantages of thermal plasma. (Author)

  11. Thermal stability of the tokamak plasma edge

    International Nuclear Information System (INIS)

    Stacey, W.M.

    1997-01-01

    The general linear, fluid, thermal instability theory for the plasma edge has been extended. An analysis of a two-dimensional fluid model of the plasma edge has identified the importance of many previously unappreciated phenomena associated with parallel and gyroviscous forces in the presence of large radial gradients, with large radial or parallel flows, with the temperature dependence of transport coefficients, and with the coupling of temperature, flow and density perturbations. The radiative condensation effect is generalized to include a further destabilizing condensation effect associated with radial heat conduction. Representative plasma edge neutral and impurity densities are found to be capable of driving thermal instabilities in the edge transport barrier and radiative mantle, respectively. (author)

  12. Generators of nonequilibrium low-temperature plasma

    International Nuclear Information System (INIS)

    Dautov, G.Yu.

    1988-01-01

    Results are described of a study and of the characteristics of sources of a non-equilibrium gas-discharge plasma. The plasma generators considered include glow, high frequency, and arc discharge generators. Thermodynamic, ionic, and electronic processes occurring in the plasmas are evaluated

  13. Solar thermal aided power generation

    International Nuclear Information System (INIS)

    Hu, Eric; Yang, YongPing; Nishimura, Akira; Yilmaz, Ferdi; Kouzani, Abbas

    2010-01-01

    Fossil fuel based power generation is and will still be the back bone of our world economy, albeit such form of power generation significantly contributes to global CO 2 emissions. Solar energy is a clean, environmental friendly energy source for power generation, however solar photovoltaic electricity generation is not practical for large commercial scales due to its cost and high-tech nature. Solar thermal is another way to use solar energy to generate power. Many attempts to establish solar (solo) thermal power stations have been practiced all over the world. Although there are some advantages in solo solar thermal power systems, the efficiencies and costs of these systems are not so attractive. Alternately by modifying, if possible, the existing coal-fired power stations to generate green sustainable power, a much more efficient means of power generation can be reached. This paper presents the concept of solar aided power generation in conventional coal-fired power stations, i.e., integrating solar (thermal) energy into conventional fossil fuelled power generation cycles (termed as solar aided thermal power). The solar aided power generation (SAPG) concept has technically been derived to use the strong points of the two technologies (traditional regenerative Rankine cycle with relatively higher efficiency and solar heating at relatively low temperature range). The SAPG does not only contribute to increase the efficiencies of the conventional power station and reduce its emission of the greenhouse gases, but also provides a better way to use solar heat to generate the power. This paper presents the advantages of the SAPG at conceptual level.

  14. Synthesis of functional nanocrystallites through reactive thermal plasma processing

    Directory of Open Access Journals (Sweden)

    Takamasa Ishigaki and Ji-Guang Li

    2007-01-01

    Full Text Available A method of synthesizing functional nanostructured powders through reactive thermal plasma processing has been developed. The synthesis of nanosized titanium oxide powders was performed by the oxidation of solid and liquid precursors. Quench gases, either injected from the shoulder of the reactor or injected counter to the plasma plume from the bottom of the reactor, were used to vary the quench rate, and therefore the particle size, of the resultant powders. The experimental results are well supported by numerical analysis on the effects of the quench gas on the flow pattern and temperature field of the thermal plasma as well as on the trajectory and temperature history of the particles. The plasma-synthesized TiO2 nanoparticles showed phase preferences different from those synthesized by conventional wet-chemical processes. Nanosized particles of high crystallinity and nonequilibrium chemical composition were formed in one step via reactive thermal plasma processing.

  15. Radial thermal diffusivity of toroidal plasma affected by resonant magnetic perturbations

    International Nuclear Information System (INIS)

    Kanno, Ryutaro; Nunami, Masanori; Satake, Shinsuke; Takamaru, Hisanori; Okamoto, Masao

    2012-04-01

    We investigate how the radial thermal diffusivity of an axisymmetric toroidal plasma is modified by effect of resonant magnetic perturbations (RMPs), using a drift kinetic simulation code for calculating the thermal diffusivity in the perturbed region. The perturbed region is assumed to be generated on and around the resonance surfaces, and is wedged in between the regular closed magnetic surfaces. It has been found that the radial thermal diffusivity χ r in the perturbed region is represented as χ r = χ r (0) {1 + c r parallel 2 >}. Here r parallel 2 > 1/2 is the strength of the RMPs in the radial directions, means the flux surface average defined by the unperturbed (i.e., original) magnetic field, χ r (0) is the neoclassical thermal diffusivity, and c is a positive coefficient. In this paper, dependence of the coefficient c on parameters of the toroidal plasma is studied in results given by the δ f simulation code solving the drift kinetic equation under an assumption of zero electric field. We find that the dependence of c is given as c ∝ ω b /ν eff m in the low collisionality regime ν eff b , where ν eff is the effective collision frequency, ω b is the bounce frequency and m is the particle mass. In case of ν eff > ω b , the thermal diffusivity χ r evaluated by the simulations becomes close to the neoclassical thermal diffusivity χ r (0) . (author)

  16. System and method for generating steady state confining current for a toroidal plasma fusion reactor

    International Nuclear Information System (INIS)

    Bers, A.

    1981-01-01

    A system for generating steady state confining current for a toroidal plasma fusion reactor providing steady-state generation of the thermonuclear power. A dense, hot toroidal plasma is initially prepared with a confining magnetic field with toroidal and poloidal components. Continuous wave rf energy is injected into said plasma to estalish a spectrum of traveling waves in the plasma, where the traveling waves have momentum components substantially either all parallel, or all anti-parallel to the confining magnetic field. The injected rf energy is phased to couple to said traveling waves with both a phase velocity component and a wave momentum component in the direction of the plasma traveling wave components. The injected rf energy has a predetermined spectrum selected so that said traveling waves couple to plasma electrons having velocities in a predetermined range delta . The velocities in the range are substantially greater than the thermal electron velocity of the plasma. In addition, the range is sufficiently broad to produce a raised plateau having width delta in the plasma electron velocity distribution so that the plateau electrons provide steady-state current to generate a poloidal magnetic field component sufficient for confining the plasma. In steady state operation of the fusion reactor, the fusion power density in the plasma exceeds the power dissipated inthe plasma

  17. An ECR table plasma generator

    International Nuclear Information System (INIS)

    Racz, R.; Palinkas, J.; Bin, S.

    2012-01-01

    A compact ECR plasma device was built in our lab using the 'spare parts' of the ATOMKI ECR ion source. We call it 'ECR Table Plasma Generator'. It consists of a relatively big plasma chamber (ID=10 cm, L=40 cm) in a thin NdFeB hexapole magnet with independent vacuum and gas dosing systems. For microwave coupling two low power TWTAs (Travelling Wave tube amplifier) can be applied individually or simultaneously, operating in the 6-18 GHz range. There is no axial magnetic trap and there is no extraction. The technical details of the plasma generator and preliminary plasma photo study results are shown. This paper is followed by the associated poster. (authors)

  18. Hollow core plasma channel generation

    International Nuclear Information System (INIS)

    Quast, Heinrich Martin

    2018-03-01

    The use of a hollow plasma channel in plasma-based acceleration has beneficial properties for the acceleration of electron and positron bunches. In the scope of the FLASHForward facility at DESY, the generation of such a plasma structure is examined. Therefore, the generation of a ring-shaped laser intensity profile with different techniques is analyzed. From the obtained intensity profiles the electron density of a hollow plasma channel is simulated in the focal region. Different parameters are scanned to understand their influence on the electron density distribution - an important parameter being, for example, the radius of the central region of the channel. In addition to the simulations, experiments are presented, during which a laser pulse is transformed into a hollow beam with a spiral phase plate. Subsequently, it forms a plasma during the interaction with hydrogen, where the plasma is imaged with interferometry. For energies above 0.9 mJ a hollow plasma structure can be observed at the location of first plasma formation.

  19. High duty factor Plasma Generator for CERN’s Superconducting Proton Linac

    CERN Document Server

    Lettry, J; Scrivens, R; Chaudet, E; Faircloth, D; Favre, G; Geisser, JM; Kuchler, D; Mathot, S; Midttun, O; Paoluzzi, M; Schmitzer, C; Steyaert, D

    2010-01-01

    CERN’s Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN’s PS-Booster. Its ion source is a non-cesiated RF driven H- volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H- during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the LHC, it consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV Synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H- during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H- plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the...

  20. Coherent bremsstrahlung generation of harmonics in a laser-produced plasma

    International Nuclear Information System (INIS)

    Silin, Viktor P

    1999-01-01

    Foundations of a theory of generation of the harmonics of a laser pump in a fully ionised plasma are proposed. This theory makes it possible to describe the relationships governing harmonic generation in an analytical form. For an elliptically polarised pump field with a low degree of circular polarisation A, the range of plasma parameters is established in which the number of harmonics is found to be of the order of A -1 . Anomalous polarisation properties of the harmonics are predicted. In this case, their polarisation is seen to be nearly perpendicular to the pump polarisation and the degree of circular polarisation increases with the harmonic order number. The harmonic-order-dependent intensity of the pump field which results in circular polarisation of a harmonic is determined making allowance for thermal plasma motion. The conditions under which increasing the low degree of circular pump polarisation increases the efficiency of harmonic generation are established. The nonlinear dependence of the pump polarisation on its intensity under the conditions of collisional absorption in a plasma are identified and an instability of the circular polarisation is revealed. For a plane-polarised pump, it is shown how the maximum power of a harmonic and the pump power corresponding to this maximum scale up with the harmonic order number. The conditions under which the number of harmonics generated is limited owing to the relativistic nature of electron motion in the pump field are established. This effect appears for an unexpectedly weak relativity. (invited paper)

  1. Non-thermal atmospheric-pressure plasma possible application in wound healing.

    Science.gov (United States)

    Haertel, Beate; von Woedtke, Thomas; Weltmann, Klaus-Dieter; Lindequist, Ulrike

    2014-11-01

    Non-thermal atmospheric-pressure plasma, also named cold plasma, is defined as a partly ionized gas. Therefore, it cannot be equated with plasma from blood; it is not biological in nature. Non-thermal atmospheric-pressure plasma is a new innovative approach in medicine not only for the treatment of wounds, but with a wide-range of other applications, as e.g. topical treatment of other skin diseases with microbial involvement or treatment of cancer diseases. This review emphasizes plasma effects on wound healing. Non-thermal atmospheric-pressure plasma can support wound healing by its antiseptic effects, by stimulation of proliferation and migration of wound relating skin cells, by activation or inhibition of integrin receptors on the cell surface or by its pro-angiogenic effect. We summarize the effects of plasma on eukaryotic cells, especially on keratinocytes in terms of viability, proliferation, DNA, adhesion molecules and angiogenesis together with the role of reactive oxygen species and other components of plasma. The outcome of first clinical trials regarding wound healing is pointed out.

  2. Applying chemical engineering concepts to non-thermal plasma reactors

    Science.gov (United States)

    Pedro AFFONSO, NOBREGA; Alain, GAUNAND; Vandad, ROHANI; François, CAUNEAU; Laurent, FULCHERI

    2018-06-01

    Process scale-up remains a considerable challenge for environmental applications of non-thermal plasmas. Undersanding the impact of reactor hydrodynamics in the performance of the process is a key step to overcome this challenge. In this work, we apply chemical engineering concepts to analyse the impact that different non-thermal plasma reactor configurations and regimes, such as laminar or plug flow, may have on the reactor performance. We do this in the particular context of the removal of pollutants by non-thermal plasmas, for which a simplified model is available. We generalise this model to different reactor configurations and, under certain hypotheses, we show that a reactor in the laminar regime may have a behaviour significantly different from one in the plug flow regime, often assumed in the non-thermal plasma literature. On the other hand, we show that a packed-bed reactor behaves very similarly to one in the plug flow regime. Beyond those results, the reader will find in this work a quick introduction to chemical reaction engineering concepts.

  3. Runaway electron generation during plasma shutdown by killer pellet injection

    International Nuclear Information System (INIS)

    Gal, K; Feher, T; Smith, H; Fueloep, T; Helander, P

    2008-01-01

    Tokamak discharges are sometimes terminated by disruptions that may cause large mechanical and thermal loads on the vessel. To mitigate disruption-induced problems it has been proposed that 'killer' pellets could be injected into the plasma in order to safely terminate the discharge. Killer pellets enhance radiative energy loss and thereby lead to rapid cooling and shutdown of the discharge. But pellets may also cause runaway electron generation, as has been observed in experiments in several tokamaks. In this work, runaway dynamics in connection with deuterium or carbon pellet-induced fast plasma shutdown is considered. A pellet code, which calculates the material deposition and initial cooling caused by the pellet is coupled to a runaway code, which determines the subsequent temperature evolution and runaway generation. In this way, a tool has been created to test the suitability of different pellet injection scenarios for disruption mitigation. If runaway generation is avoided, the resulting current quench times are too long to safely avoid large forces on the vessel due to halo currents

  4. Antimicrobial properties of uncapped silver nanoparticles synthesized by DC arc thermal plasma technique.

    Science.gov (United States)

    Shinde, Manish; Patil, Rajendra; Karmakar, Soumen; Bhoraskar, Sudha; Rane, Sunit; Gade, Wasudev; Amalnerkar, Dinesh

    2012-02-01

    We, herein, report the antimicrobial properties of uncapped silver nanoparticles for a Gram positive model organism, Bacillus subtilis. Uncapped silver nanoparticles have been prepared using less-explored DC arc thermal plasma technique by considering its large scale generation capability. It is observed that the resultant nanoparticles show size as well as optical property dependent antimicrobial effect.

  5. The use of cold plasma generators in medicine

    Directory of Open Access Journals (Sweden)

    Kolomiiets R.O.

    2017-04-01

    Full Text Available Cold plasma treatment of wounds is a modern area of therapeutic medicine. We describe the physical mechanisms of cold plasma, the principles of therapeutic effects and design of two common types of cold plasma generators for medical use. This work aims at disclosing the basic principles of construction of cold atmospheric plasma generators in medicine and prospects for their further improvement. The purpose of this work is to improve the existing cold atmospheric plasma generators for use in medical applications. Novelty of this work consists in the application of new principles of construction of cold atmospheric plasmas medical apparatus, namely the combination of the gas discharge chamber, electrodes complex shape forming device and plasma flow in a single package. This helps to achieve a significant reduction in the size of the device, and a discharge chamber design change increases the therapeutic effect. The design of cold atmospheric plasma generator type «pin-to-hole», which is able to control parameters using the plasma current (modulation fluctuations in the primary winding and mechanically (using optional rotary electrode. It is also possible to combine some similar generators in the set, which will increase the surface area of the plasma treatment. We consider the basic principles of generating low atmospheric plasma flow, especially the formation of the plasma jet, changing its shape and modulation stream. The features of cold plasma generator design and information about prospects for further application, and opportunities for further improvement are revealed. The recommendations for further use of cold atmospheric plasma generators in medicine are formulated.

  6. Horizontal steam generator thermal-hydraulics

    Energy Technology Data Exchange (ETDEWEB)

    Ubra, O. [SKODA Praha Company, Prague (Czechoslovakia); Doubek, M. [Czech Technical Univ., Prague (Czechoslovakia)

    1995-09-01

    Horizontal steam generators are typical components of nuclear power plants with pressure water reactor type VVER. Thermal-hydraulic behavior of horizontal steam generators is very different from the vertical U-tube steam generator, which has been extensively studied for several years. To contribute to the understanding of the horizontal steam generator thermal-hydraulics a computer program for 3-D steady state analysis of the PGV-1000 steam generator has been developed. By means of this computer program, a detailed thermal-hydraulic and thermodynamic study of the horizontal steam generator PGV-1000 has been carried out and a set of important steam generator characteristics has been obtained. The 3-D distribution of the void fraction and 3-D level profile as functions of load and secondary side pressure have been investigated and secondary side volumes and masses as functions of load and pressure have been evaluated. Some of the interesting results of calculations are presented in the paper.

  7. System and method for generating steady state confining current for a toroidal plasma fusion reactor

    International Nuclear Information System (INIS)

    Fisch, N.J.

    1981-01-01

    A system for generating steady state confining current for a toroidal plasma fusion reactor providing steady-state generation of the thermonuclear power. A dense, hot toroidal plasma is initially prepared with a confining magnetic field with toroidal and poloidal components. Continuous wave rf energy is injected into said plasma to establish a spectrum of traveling waves in the plasma, where the traveling waves have momentum components substantially either all parallel, or all anti-parallel to the confining magnetic field. The injected rf energy is phased to couple to said traveling waves with both a phase velocity component and a wave momentum component in the direction of the plasma traveling wave components. The injected rf energy has a predetermined spectrum selected so that said traveling waves couple to plasma electrons having velocities in a predetermined range delta . The velocities in the range are substantially greater than the thermal electron velocity of the plasma. In addition, the range is sufficiently broad to produce a raised plateau having width delta in the plasma electron velocity distribution so that the plateau electrons provide steady-state current to generate a poloidal magnetic field component sufficient for confining the plasma. In steady state operation of the fusion reactor, the fusion power density in the plasma exceeds the power dissipated in the plasma

  8. A plasma needle generates nitric oxide

    International Nuclear Information System (INIS)

    Stoffels, E; Gonzalvo, Y Aranda; Whitmore, T D; Seymour, D L; Rees, J A

    2006-01-01

    Generation of nitric oxide (NO) by a plasma needle is studied by means of mass spectrometry. The plasma needle is an atmospheric glow generated by a radio-frequency excitation in a mixture of helium and air. This source is used for the treatment of living tissues, and nitric oxide may be one of the most important active agents in plasma therapy. Efficient NO generation is of particular importance in the treatment of cardiovascular diseases. Mass spectrometric measurements have been performed under various plasma conditions; gas composition in the plasma and conversion of feed gases (nitrogen and oxygen) into other species has been studied. Up to 30% of the N 2 and O 2 input is consumed in the discharge, and NO has been identified as the main conversion product

  9. Arc generators of low-temperature plasma

    International Nuclear Information System (INIS)

    Krolikowski, Cz.; Niewiedzial, R.; Siwiec, J.

    1979-01-01

    This paper is a review of works concerning investigation and use of low-temperature plasma in arc plasma generators made in Electric Power Institute of PP. There are discussed: analytical approach to a problem of volt-current and operational characteristics of DC arc plasma generators, determination of limits of their stable work and possibilities of their use to technological aims. (author)

  10. Development and evaluation of suspension plasma sprayed yttria stabilized zirconia coatings as thermal barriers

    Science.gov (United States)

    van Every, Kent J.

    The insulating effects from thermal barrier coatings (TBCs) in gas turbine engines allow for increased operational efficiencies and longer service lifetimes. Consequently, improving TBCs can lead to enhanced gas turbine engine performance. This study was conducted to investigate if yttria-stabilized zirconia (YSZ) coatings, the standard industrial choice for TBCs, produced from nano-sized powder could provide better thermal insulation than current commericial YSZ coatings generated using micron-sized powders. The coatings for this research were made via the recently developed suspension plasma spraying (SPS) process. With SPS, powders are suspended in a solvent containing dispersing agents; the suspension is then injected directly into a plasma flow that evaporates the solvent and melts the powder while transporting it to the substrate. Although related to the industrial TBC production method of air plasma spraying (APS), SPS has two important differences---the ability to spray sub-micron diameter ceramic particles, and the ability to alloy the particles with chemicals dissolved in the solvent. These aspects of SPS were employed to generate a series of coatings from suspensions containing ˜100 nm diameter YSZ powder particles, some of which were alloyed with neodymium and ytterbium ions from the solvent. The SPS coatings contained columnar structures not observed in APS TBCs; thus, a theory was developed to explain the formation of these features. The thermal conductivity of the coatings was tested to evaluate the effects of these unique microstructures and the effects of the alloying process. The results for samples in the as-sprayed and heat-treated conditions were compared to conventional YSZ TBCs. This comparison showed that, relative to APS YSZ coatings, the unalloyed SPS samples typically exhibited higher as-sprayed and lower heat-treated thermal conductivities. All thermal conductivity values for the alloyed samples were lower than conventional YSZ TBCs

  11. Performance Testing of Suspension Plasma Sprayed Thermal Barrier Coatings Produced with Varied Suspension Parameters

    Directory of Open Access Journals (Sweden)

    Nicholas Curry

    2015-07-01

    Full Text Available Suspension plasma spraying has become an emerging technology for the production of thermal barrier coatings for the gas turbine industry. Presently, though commercial systems for coating production are available, coatings remain in the development stage. Suitable suspension parameters for coating production remain an outstanding question and the influence of suspension properties on the final coatings is not well known. For this study, a number of suspensions were produced with varied solid loadings, powder size distributions and solvents. Suspensions were sprayed onto superalloy substrates coated with high velocity air fuel (HVAF -sprayed bond coats. Plasma spray parameters were selected to generate columnar structures based on previous experiments and were maintained at constant to discover the influence of the suspension behavior on coating microstructures. Testing of the produced thermal barrier coating (TBC systems has included thermal cyclic fatigue testing and thermal conductivity analysis. Pore size distribution has been characterized by mercury infiltration porosimetry. Results show a strong influence of suspension viscosity and surface tension on the microstructure of the produced coatings.

  12. Study of the thermal and suprathermal electron density fluctuations of the plasma in the Focus experiment

    International Nuclear Information System (INIS)

    Jolas, A.

    1981-10-01

    An experiment on Thomson scattering of ruby laser light by the electrons of a plasma produced by an intense discharge between the electrodes of a coaxial gun in a gas at low pressure has been carried out. It is shown that the imploding plasma is made up of layers with different characteristics: a dense plasma layer where the density fluctuations are isotropic and have a thermal level, and a tenuous plasma layer where the fluctuations are anisotropic, and strongly suprathermal. The suprathermal fluctuations are attributed to microscopic instabilities generated by the electric current circulating in the transition zone where the magnetic field penetrates the plasma [fr

  13. Optimization of Non-Thermal Plasma Treatment in an In Vivo Model Organism.

    Directory of Open Access Journals (Sweden)

    Amanda Lee

    Full Text Available Non-thermal plasma is increasingly being recognized for a wide range of medical and biological applications. However, the effect of non-thermal plasma on physiological functions is not well characterized in in vivo model systems. Here we use a genetically amenable, widely used model system, Drosophila melanogaster, to develop an in vivo system, and investigate the role of non-thermal plasma in blood cell differentiation. Although the blood system in Drosophila is primitive, it is an efficient system with three types of hemocytes, functioning during different developmental stages and environmental stimuli. Blood cell differentiation in Drosophila plays an essential role in tissue modeling during embryogenesis, morphogenesis and also in innate immunity. In this study, we optimized distance and frequency for a direct non-thermal plasma application, and standardized doses to treat larvae and adult flies so that there is no effect on the viability, fertility or locomotion of the organism. We discovered that at optimal distance, time and frequency, application of plasma induced blood cell differentiation in the Drosophila larval lymph gland. We articulate that the augmented differentiation could be due to an increase in the levels of reactive oxygen species (ROS upon non-thermal plasma application. Our studies open avenues to use Drosophila as a model system in plasma medicine to study various genetic disorders and biological processes where non-thermal plasma has a possible therapeutic application.

  14. Solar energy thermally powered electrical generating system

    Science.gov (United States)

    Owens, William R. (Inventor)

    1989-01-01

    A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.

  15. Diagnostic methods of thermal dusty plasma flows

    International Nuclear Information System (INIS)

    Nefedov, A.P.

    1995-01-01

    The presence in the high-temperature flows of condensed disperse phase (CDP) particles may lead either to an increase of the electron number density n e if the particles assume a positive charge or to its decrease if the charge is negative. The existence of CDP also may effect on optical parameters of the thermal dusty plasma flows, on heat and radiative transfer in the plasma. The entire range of states, from a Debye plasma to a highly nonideal system of charged particles, is realized in a thermal dusty plasma under standard conditions T=2000-3000 K, n e =10 8 - 10 14 cm -3 . The advanced probe and optical diagnostic instruments are needed to study the optical and electrophysical properties of thermal dusty plasma flows. The diagnostic techniques must give the data about such parameters of gas and dispersed phase as temperatures of gas and particles, number densities of electrons, atoms and ions of alkali metals, sizes, velocities and concentrations of CDP particles. It should be noted that number density of alkali metal atoms and gas temperature may be measured by the well known full absorption and generalized reversal methods. This paper describes the probe and optical techniques for diagnostic of dusty plasma flows developed in High Energy Density Research Center of Russian Academy of Sciences. The Forward Angle Scattering Transmissometer (FAST) allows measurement of the average size (Sauter diameter), mass number density, and refractive index of particles in the 0.5-15.0 gm size range. The basis of the method is a dependence of the measured extinction of radiation upon an angular acceptance aperture of the photo detector. The FAST instrument allows one to determine the mass density and the Sauter diameter of a polydispersion of particles without a priori specification of the particle size distribution model and exact data about the article refractive index

  16. Diagnostic methods of thermal dusty plasma flows

    International Nuclear Information System (INIS)

    Nefedov, A.P.

    1995-01-01

    The presence in the high-temperature flows of condensed disperse phase (CDP) particles may lead either to an increase of the electron number density n e if the particles assume a positive charge or to its decrease if the charge is negative. The existence of CDP also may effect on optical parameters of the thermal dusty plasma flows, on heat and radiative transfer in the plasma. The entire range of states, from a Debye plasma to a highly nonideal system of charged particles, is realized in a thermal dusty plasma under standard conditions T=2000-3000 K, n e =10 8 -10 14 cm -3 . The advanced probe and optical diagnostic instruments are needed to study the optical and electrophysical properties of thermal dusty plasma flows. The diagnostic techniques must give the data about such parameters of gas and dispersed phase as temperatures of gas and particles, number densities of electrons, atoms and ions of alkali metals, sizes, velocities and concentrations of CDP particles. It should be noted that number density of alkali metal atoms and gas temperature may be measured by the well known full absorption and generalized reversal methods. This paper describes the probe and optical techniques for diagnostic of dusty plasma flows developed in High Energy Density Research Center of Russian Academy of Sciences. The Forward Angle Scattering Transmissometer (FAST) allows measurement of the average size (Sauter diameter), mass number density, and refractive index of particles in the 0.5-15.0 μm size range. The basis of the method is a dependence of the measured extinction of radiation upon an angular acceptance aperture of the photo detector. The FAST instrument allows one to determine the mass density and the Sauter diameter of a polydispersion of particles without a priori specification of the particle size distribution model and exact data about the particle refractive index

  17. Self-organization process of a magnetohydrodynamic plasma in the presence of thermal conduction

    International Nuclear Information System (INIS)

    Zhu, Shao-ping; Horiuchi, Ritoku; Sato, Tetsuya; Watanabe, K.; Hayashi, T.; Todo, Y.; Watanabe, T.H.; Kageyama, A.; Takamaru, H.

    1995-12-01

    A self-organization process of a magnetohydrodynamic(MHD) plasma with a finite thermal conductivity is investigated by means of a three-dimensional MHD simulation. With no thermal conduction an MHD system self-organizes to a non-Taylor's state in which the electric current perpendicular to the magnetic field remains comparable to the parallel electric current. In the presence of thermal conductivity the perpendicular component of electric current and the nonuniformity of thermal pressure generated by driven reconnection tend to be smoothened. Thus, the self-organized state approaches to a force-free minimum energy state under the influence of thermal conduction. Detailed energy conversion processes are also studied to find that the rapid decay of magnetic energy during the self-organization process is caused not only through the ohmic heating, but also through the work done by the j x B force. (author)

  18. Thermal radiation properties of PTFE plasma

    Science.gov (United States)

    Liu, Xiangyang; Wang, Siyu; Zhou, Yang; Wu, Zhiwen; Xie, Kan; Wang, Ningfei

    2017-06-01

    To illuminate the thermal transfer mechanism of devices adopting polytetrafluoroethylene (PTFE) as ablation materials, the thermal radiation properties of PTFE plasma are calculated and discussed based on local thermodynamic equilibrium (LTE) and optical thin assumptions. It is clarified that line radiation is the dominant mechanism of PTFE plasma. The emission coefficient shows an opposite trend for both wavelength regions divided by 550 nm at a temperature above 15 000 K. The emission coefficient increases with increasing temperature and pressure. Furthermore, it has a good log linear relation with pressure. Equivalent emissivity varies complexly with temperature, and has a critical point between 20 000 K to 25 000 K. The equivalent cross points of the average ionic valence and radiation property are about 10 000 K and 15 000 K for fully single ionization.

  19. Realization of thermally durable close-packed 2D gold nanoparticle arrays using self-assembly and plasma etching

    International Nuclear Information System (INIS)

    Sivaraman, Sankar K; Santhanam, Venugopal

    2012-01-01

    Realization of thermally and chemically durable, ordered gold nanostructures using bottom-up self-assembly techniques are essential for applications in a wide range of areas including catalysis, energy generation, and sensing. Herein, we describe a modular process for realizing uniform arrays of gold nanoparticles, with interparticle spacings of 2 nm and above, by using RF plasma etching to remove ligands from self-assembled arrays of ligand-coated gold nanoparticles. Both nanoscale imaging and macroscale spectroscopic characterization techniques were used to determine the optimal conditions for plasma etching, namely RF power, operating pressure, duration of treatment, and type of gas. We then studied the effect of nanoparticle size, interparticle spacing, and type of substrate on the thermal durability of plasma-treated and untreated nanoparticle arrays. Plasma-treated arrays showed enhanced chemical and thermal durability, on account of the removal of ligands. To illustrate the application potential of the developed process, robust SERS (surface-enhanced Raman scattering) substrates were formed using plasma-treated arrays of silver-coated gold nanoparticles that had a silicon wafer or photopaper as the underlying support. The measured value of the average SERS enhancement factor (2 × 10 5 ) was quantitatively reproducible on both silicon and paper substrates. The silicon substrates gave quantitatively reproducible results even after thermal annealing. The paper-based SERS substrate was also used to swab and detect probe molecules deposited on a solid surface. (paper)

  20. Stationary self-focusing of Gaussian laser beam in relativistic thermal quantum plasma

    International Nuclear Information System (INIS)

    Patil, S. D.; Takale, M. V.

    2013-01-01

    In the present paper, we have employed the quantum dielectric response in thermal quantum plasma to model relativistic self-focusing of Gaussian laser beam in a plasma. We have presented an extensive parametric investigation of the dependence of beam-width parameter on distance of propagation in relativistic thermal quantum plasma. We have studied the role of Fermi temperature in the phenomenon of self-focusing. It is found that the quantum effects cause much higher oscillations of beam-width parameter and better relativistic focusing of laser beam in thermal quantum plasma in comparison with that in the relativistic cold quantum plasma and classical relativistic plasma. Our computations show more reliable results in comparison to the previous works

  1. Induction of Immunogenic Cell Death with Non-Thermal Plasma for Cancer Immunotherapy

    Science.gov (United States)

    Lin, Abraham G.

    Even with the recent advancements in cancer immunotherapy, treatments are still associated with debilitating side effects and unacceptable fail rates. Induction of immunogenic cell death (ICD) in tumors is a promising approach to cancer treatment that may overcome these deficiencies. Cells undergoing ICD pathways enhance the interactions between cancerous cells and immune cells of the patient, resulting in the generation of anti-cancer immunity. The goal of this therapy relies on the engagement and reestablishment of the patient's natural immune processes to target and eliminate cancerous cells systemically. The main objective of this research was to determine if non-thermal plasma could be used to elicit immunogenic cancer cell death for cancer immunotherapy. My hypothesis was that plasma induces immunogenic cancer cell death through oxidative stress pathways, followed by development of a specific anti-tumor immune response. This was tested by investigating the interactions between plasma and multiple cancerous cells in vitro and validating anti-tumor immune responses in vivo. Following plasma treatment, two surrogate ICD markers, secreted adenosine triphosphate (ATP) and surface exposed calreticulin (ecto-CRT), were emitted from all three cancerous cell lines tested: A549 lung carcinoma cell line, CNE-1 radiation-resistant nasopharyngeal cell line and CT26 colorectal cancer cell line. When these cells were co-cultured with macrophages, cells of the innate immune system, the tumoricidal activity of macrophages was enhanced, thus demonstrating the immunostimulatory activity of cells undergoing ICD. The underlying mechanisms of plasma-induced ICD were also evaluated. When plasma is generated, four major components are produced: electromagnetic fields, ultraviolet radiation, and charged and neutral reactive species. Of these, we determined that plasma-generated charged and short-lived reactive oxygen species (ROS) were the major effectors of ICD. Following plasma

  2. Functionalization of polymer surfaces by medium frequency non-thermal plasma

    Science.gov (United States)

    Felix, T.; Trigueiro, J. S.; Bundaleski, N.; Teodoro, O. M. N. D.; Sério, S.; Debacher, N. A.

    2018-01-01

    This work addresses the surface modification of different polymers by argon dielectric barrier discharge, using bromoform vapours. Atomic Force Microscopy and Scanning Electron Microscopy showed that plasma etching occurs in stages and may be related to the reach of the species generated and obviously the gap between the electrodes. In addition, the stages of flatten surface or homogeneity may be the result of the transient crosslinking promoted by the intense UV radiation generated by the non- thermal plasma. X-ray Photoelectron Spectroscopy analysis showed that bromine was inserted on the polymer surface as Csbnd Br bonds and as adsorbed HBr. The obtained results demonstrate that the highest degree of bromofunctionalization was achieved on polypropylene surface, which contains about 8,5% of Br. After its derivatization in ammonia, Br disappeared and about 6% of nitrogen in the form of amine group was incorporated at the surface. This result can be considered as a clear fingerprint of the Br substitution by the amine group, thus illustrating the efficiency of the proposed method for functionalization of polymer surfaces.

  3. High speed and high functional inverter power supplies for plasma generation and control, and their performance

    International Nuclear Information System (INIS)

    Uesugi, Yoshihiko; Razzak, Mohammad A.; Kondo, Kenji; Kikuchi, Yusuke; Takamura, Shuichi; Imai, Takahiro; Toyoda, Mitsuhiro

    2003-01-01

    The Rapid development of high power and high speed semiconductor switching devices has led to their various applications in related plasma fields. Especially, a high speed inverter power supply can be used as an RF power source instead of conventional linear amplifiers and a power supply to control the magnetic field in a fusion plasma device. In this paper, RF thermal plasma production and plasma heating experiments are described emphasis placed on using a static induction transistor inverter at a frequency range between 200 kHz and 2.5 MHz as an RF power supply. Efficient thermal plasma production is achieved experimentally by using a flexible and easily operated high power semiconductor inverter power supply. Insulated gate bipolar transistor (IGBT) inverter power supplies driven by a high speed digital signal processor are applied as tokamak joule coil and vertical coil power supplies to control plasma current waveform and plasma equilibrium. Output characteristics, such as the arbitrary bipolar waveform generation of a pulse width modulation (PWM) inverter using digital signal processor (DSP) can be successfully applied to tokamak power supplies for flexible plasma current operation and fast position control of a small tokamak. (author)

  4. Thermal plasma synthesis of Fe1−xNix alloy nanoparticles

    International Nuclear Information System (INIS)

    Raut, Suyog A.; Kanhe, Nilesh S.; Bhoraskar, S. V.; Mathe, V. L.; Das, A. K.

    2014-01-01

    Fe-Ni alloy nanoparticles are of great interest because of diverse practical applications in the fields such as magnetic fluids, high density recording media, catalysis and medicine. We report the synthesis of Fe-Ni nanoparticles via thermal plasma route. Thermal plasma assisted synthesis is a high temperature process and gives high yields of production. Here, we have used direct arc thermal plasma plume of 6kw as a source of energy at operating pressure 500 Torr. The mixture of Fe-Ni powder in required proportion (Fe 1−x Ni x ; x=0.30, 0.32, 0.34, 0.36, 0.38 and 0.40) was made to evaporate simultaneously from the graphite anode in thermal plasma reactor to form Fe-Ni bimetallic nanoparticles. The as synthesized particles were characterized by X-Ray Diffraction (XRD), Thermo-Gravimetric Analysis/Differential Scanning Calorimtry (TGA/DSC)

  5. Synthesis of {gamma}-aluminium oxynitride spinel using thermal plasma technique

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Pravuram; Singh, S. K.; Sinha, S. P. [School of Applied Science (Physics), KIIT University, Bhubaneswar 751024 (India); Advanced Materials Technology Department, IMMT (CSIR), Bhubaneswar 751013 (India); School of Applied Science (Physics), KIIT University, Bhubaneswar 751024 (India)

    2012-07-23

    The synthesis technique of {gamma}-AlON in NH{sub 3} plasma using extended arc thermal plasma reactor have been reported. Dense cubic AlON spinel was synthesized in liquid state by fusion of mixture of Al{sub 2}O{sub 3} and AlN powder under thermal plasma. The density of the fused AlON was found to be 3.64 g/cc which is 98.11% of theoretical value. The formation of AlON was confirmed from XRD and Raman studies. Well faceted structure of plasma fused AlON was observed in FE-SEM micrograph.

  6. Plasma processes and film growth of expanding thermal plasma deposited textured zinc oxide

    NARCIS (Netherlands)

    Groenen, R.; Linden, J.L.; Sanden, van de M.C.M.

    2005-01-01

    Plasma processes and film growth of textured zinc oxide deposited from oxygen and diethyl zinc utilizing expanding thermal argon plasma created by a cascaded arc is discussed. In all conditions explored, an excess of argon ions and low temperature electrons is available, which represent the

  7. Cytocompatibility of Plasma and Thermally Treated Biopolymers

    Directory of Open Access Journals (Sweden)

    Petr Slepička

    2013-01-01

    Full Text Available This paper is focused on the surface characterization of plasma and consequently thermally treated biocompatible polymers. PLLA (poly(L-lactide acid and PMP (poly-4-methyl-1-pentene are studied. The influence of Ar plasma treatment on the surface polarity of substrate measured immediately after treatment and during the polymer surface aging is studied. Surface roughness, morphology, wettability, and surface chemistry were determined. Plasma treatment leads to significant changes in PLLA surface morphology and chemistry, with the PMP being slightly affected. The higher resistance to plasma fluence results in smaller ablation of PMP than that of PLLA. The plasma treatment improves cell adhesion and proliferation on the PMP. Plasma treatment of PLLA influences mostly the homogeneity of adhered and proliferated VSMC.

  8. An investigation of non-equilibrium effects in thermal argon plasmas

    International Nuclear Information System (INIS)

    Rosado, R.J.

    1981-01-01

    This thesis deals with the study of the validity of the assumption of Local Thermal Equilibrium (LTE) in the description of the parameters of a thermal argon plasma. The aim is twofold. As the studied plasma is close to, but not completely in equilibrium, the author first attempts to obtain a simple description of the plasma in terms of an LTE model in which suitable corrections for the deviations of the plasma parameters from their LTE values is introduced. To this end the plasma parameters are studied by means of a diagnostic method in which the assumption of LTE is not made. The evaluation of the usefulness of this method is the second aim of this thesis. (Auth.)

  9. Helium generated cold plasma finely regulates activation of human fibroblast-like primary cells.

    Directory of Open Access Journals (Sweden)

    Paola Brun

    Full Text Available Non-thermal atmospheric pressure plasmas are being developed for a wide range of health care applications, including wound healing. However in order to exploit the potential of plasma for clinical applications, the understanding of the mechanisms involved in plasma-induced activation of fibroblasts, the cells active in the healing process, is mandatory. In this study, the role of helium generated plasma in the tissue repairing process was investigated in cultured human fibroblast-like primary cells, and specifically in hepatic stellate cells and intestinal subepithelial myofibroblasts. Five minutes after treatment, plasma induced formation of reactive oxygen species (ROS in cultured cells, as assessed by flow cytometric analysis of fluorescence-activated 2',7'-dichlorofluorescein diacetate probe. Plasma-induced intracellular ROS were characterized by lower concentrations and shorter half-lives with respect to hydrogen peroxide-induced ROS. Moreover ROS generated by plasma treatment increased the expression of peroxisome proliferator activated receptor (PPAR-γ, nuclear receptor that modulates the inflammatory responses. Plasma exposure promoted wound healing in an in vitro model and induced fibroblast migration and proliferation, as demonstrated, respectively, by trans-well assay and partitioning between daughter cells of carboxyfluorescein diacetate succinimidyl ester fluorescent dye. Plasma-induced fibroblast migration and proliferation were found to be ROS-dependent as cellular incubation with antioxidant agents (e.g. N-acetyl L-cysteine cancelled the biological effects. This study provides evidence that helium generated plasma promotes proliferation and migration in liver and intestinal fibroblast-like primary cells mainly by increasing intracellular ROS levels. Since plasma-evoked ROS are time-restricted and elicit the PPAR-γ anti-inflammatory molecular pathway, this strategy ensures precise regulation of human fibroblast activation and

  10. Extremely high-power-density atmospheric-pressure thermal plasma jet generated by the nitrogen-boosted effect

    Science.gov (United States)

    Hanafusa, Hiroaki; Nakashima, Ryosuke; Nakano, Wataru; Higashi, Seiichiro

    2018-06-01

    In this study, the effect of N2 addition to an atmospheric-pressure Ar thermal plasma jet (TPJ) on ultrarapid heating was investigated. With increasing N2 flow rate, a boost of arc voltage to ∼36 V was observed, which significantly improved heating characteristics. As a result, a drastic power density increase from 10 to 125 kW/cm2 was achieved with the addition of 2.0 L/min N2 to 3.0 L/min Ar. The results of optical emission analysis and heating characteristics evaluation implied that dissociation and recombination of N2 molecules and the high thermal transport property of nitrogen gas play important roles in the increase in TPJ power density. Furthermore, we obtained TPJ extension with N2 addition that reached 300 mm, and it showed spatial enhancement of heat transport characteristics.

  11. What makes a thermal plasma suitable for hazardous waste disposal

    International Nuclear Information System (INIS)

    Benocci, R.; Florio, R.; Galassi, A.; Paolicchio, M.; Sindoni, E.

    1997-01-01

    The basic transport and thermodynamic characteristic of a thermal plasma are analysed in order to emphasize those properties that make a high-temperature source profitable and suitable over the conventional devices for hazardous waste treatment. In addition a survey of the basic reaction sequence and apparatus units is made together with the different approaches to thermal plasma waste treatments

  12. Transition Region Emission and the Energy Input to Thermal Plasma in Solar Flares

    Science.gov (United States)

    Holman, Gordon D.; Holman, Gordon D.; Dennis, Brian R.; Haga, Leah; Raymond, John C.; Panasyuk, Alexander

    2005-01-01

    Understanding the energetics of solar flares depends on obtaining reliable determinations of the energy input to flare plasma. X-ray observations of the thermal bremsstrahlung from hot flare plasma provide temperatures and emission measures which, along with estimates of the plasma volume, allow the energy content of this hot plasma to be computed. However, if thermal energy losses are significant or if significant energy goes directly into cooler plasma, this is only a lower limit on the total energy injected into thermal plasma during the flare. We use SOHO UVCS observations of O VI flare emission scattered by coronal O VI ions to deduce the flare emission at transition region temperatures between 100,000 K and 1 MK for the 2002 July 23 and other flares. We find that the radiated energy at these temperatures significantly increases the deduced energy input to the thermal plasma, but by an amount that is less than the uncertainty in the computed energies. Comparisons of computed thermal and nonthermal electron energies deduced from RHESSI, GOES, and UVCS are shown.

  13. Numerical Modelling of Wood Gasification in Thermal Plasma Reactor

    Czech Academy of Sciences Publication Activity Database

    Hirka, Ivan; Živný, Oldřich; Hrabovský, Milan

    2017-01-01

    Roč. 37, č. 4 (2017), s. 947-965 ISSN 0272-4324 Institutional support: RVO:61389021 Keywords : Plasma modelling * CFD * Thermal plasma reactor * Biomass * Gasification * Syngas Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.355, year: 2016 https://link.springer.com/article/10.1007/s11090-017-9812-z

  14. Characterization of a microwave generated plasma

    International Nuclear Information System (INIS)

    Root, D.J.; Mahoney, L.; Asmussen, J.

    1986-01-01

    Recent experiments have demonstrated a microwave ion beam source without and with static magnetic fields in inert gases and in oxygen gases. This plasma generation configuration also has uses in the areas of plasma processing such as plasma etching, plasma assisted thin flim deposition and plasma assisted oxide growth. These ion beam and plasma processing applications have provided motivation to investigate microwave discharge properties, such as electron density, electron temperature, gas temperature, degree of ionization, etc., of the microwave generated plasma over a wide range of experimental operating conditions. This paper presents the results of experimental measurements which attempt to characterize the experimental microwave discharge in the absence of a static magnetic field. Measurements from a double probe, which is located in the plasma in a zero microwave field region, are presented in argon, xenon and oxygen gases. Variations of plasma density and electron temperature versus absorbed microwave power, gas pressure (0.2 m Torr to 200 m Torr) and discharge diffusion length are presented and compared to dc positive column discharge theory

  15. The Tethered Balloon Current Generator - A space shuttle-tethered subsatellite for plasma studies and power generation

    Science.gov (United States)

    Williamson, P. R.; Banks, P. M.

    1976-01-01

    The objectives of the Tethered Balloon Current Generator experiment are to: (1) generate relatively large regions of thermalized, field-aligned currents, (2) produce controlled-amplitude Alfven waves, (3) study current-driven electrostatic plasma instabilities, and (4) generate substantial amounts of power or propulsion through the MHD interaction. A large balloon (a diameter of about 30 m) will be deployed with a conducting surface above the space shuttle at a distance of about 10 km. For a generally eastward directed orbit at an altitude near 400 km, the balloon, connected to the shuttle by a conducting wire, will be positive with respect to the shuttle, enabling it to collect electrons. At the same time, the shuttle will collect positive ions and, upon command, emit an electron beam to vary current flow in the system.

  16. Theory and experimental show up of axial magnetic fields self-generated in dense laser-produced plasmas

    International Nuclear Information System (INIS)

    El Tamer, M.

    1986-09-01

    The work presented in this thesis concerns the magnetic fields generated in laser produced plasma. A summary of the theoretical and experimental studies concerning the toroidal magnetic fields and realised by different groups of research is presented. Then, we present our original contribution on the generation of axial magnetic fields by the dynamo effect. The experimental work for the detection of magnetic field is based on the Faraday rotation and Zeeman effects. The experimental diagrams are detailed and discussed. The experimental results are presented and compared to the theory. Finaly, we present some consequences of the generation of the axial magnetic fields in laser produced plasma as a discussion of the thermal conductivity [fr

  17. Modeling of thermal plasma arc technology FY 1994 report

    International Nuclear Information System (INIS)

    Hawkes, G.L.; Nguyen, H.D.; Paik, S.; McKellar, M.G.

    1995-03-01

    The thermal plasma arc process is under consideration to thermally treat hazardous and radioactive waste. A computer model for the thermal plasma arc technology was designed as a tool to aid in the development and use of the plasma arc-Joule beating process. The value of this computer model is to: (a) aid in understanding the plasma arc-Joule beating process as applied to buried waste or exhumed buried waste, (b) help design melter geometry and electrode configuration, (c) calculate the process capability of vitrifying waste (i.e., tons/hour), (d) develop efficient plasma and melter operating conditions to optimize the process and/or reduce safety hazards, (e) calculate chemical reactions during treatment of waste to track chemical composition of off-gas products, and composition of final vitrified waste form and (f) help compare the designs of different plasma-arc facilities. A steady-state model of a two-dimensional axisymmetric transferred plasma arc has been developed and validated. A parametric analysis was performed that studied the effects of arc length, plasma gas composition, and input power on the temperatures and velocity profiles of the slag and plasma gas. A two-dimensional transient thermo-fluid model of the US Bureau of Mines plasma arc melter has been developed. This model includes the growth of a slag pool. The thermo-fluid model is used to predict the temperature and pressure fields within a plasma arc furnace. An analysis was performed to determine the effects of a molten metal pool on the temperature, velocity, and voltage fields within the slag. A robust and accurate model for the chemical equilibrium calculations has been selected to determine chemical composition of final waste form and off-gas based on the temperatures and pressures within the plasma-arc furnace. A chemical database has been selected. The database is based on the materials to be processed in the plasma arc furnaces

  18. Application of non-thermal plasmas to pollution control

    International Nuclear Information System (INIS)

    Penetrante, B.M.; Vogtlin, G.E.; Bardsley, J.N.; Vitello, P.A.; Wallman, P.H.

    1993-06-01

    Non-thermal plasma techniques can be used to destroy many types of hazardous molecules. They are particularly efficient when the toxic materials are present in very small concentrations. This paper discusses three particular applications of non-thermal plasmas: (1) decomposition of hydrogen sulfide (H 2 S), (2) removal of trichloroethylene (TCE), and (3) removal of nitrogen oxides (NO x ). Emphasis is placed on the energy cost for implementing the decomposition or removal of these pollutants. Some of the factors affecting the energy cost are discussed. The authors discuss in detail their work at LLNL on pulsed plasma processing for the treatment of NO x in diesel engine exhaust. The results suggest that their plasma reactor can remove up to 70% of NO with relatively high initial concentrations (up to 500 ppM) at a power consumption cost of 2.5% for an engine with an output of 14 kW and an exhaust gas flow rate of 1,200 liters per minute

  19. Application of non-thermal plasmas to pollution control

    International Nuclear Information System (INIS)

    Penetrante, B.M.; Vogtlin, G.E.; Bardsley, J.N.; Vitello, P.A.; Wallman, P.H.

    1993-01-01

    Non-thermal plasma techniques can be used to destroy many types of hazardous molecules. They are particularly efficient when the toxic materials are present in very small concentrations. This paper discusses three particular applications of non-thermal plasmas: (1) decomposition of hydrogen sulfide (H 2 S), (2) removal of trichloroethylene (TCE), and (3) removal of nitric oxides (NO x ) Emphasis is placed on the energy cost for implementing the decomposition or removal of these pollutants. Some of the factors affecting the energy cost are discussed. We discuss in detail our work at LLNL on pulsed plasma processing for the treatment of NO x in diesel engine exhaust. Our results suggest that our plasma reactor can remove up to 70% of NO x with relatively high initial concentrations (up to 500 ppM) at a power consumption cost of 2.5% for an engine with an output of 14 kill and an exhaust gas flow rate of 1200 liters per minute

  20. Finite element thermal study of the Linac4 plasma generator

    International Nuclear Information System (INIS)

    Faircloth, D.; Kronberger, M.; Kuechler, D.; Lettry, J.; Scrivens, R.

    2010-01-01

    The temperature distribution and heat flow at equilibrium of the plasma generator of the rf-powered noncesiated Linac4 H - ion source have been studied with a finite element model. It is shown that the equilibrium temperatures obtained in the Linac4 nominal operation mode (100 kW rf power, 2 Hz repetition rate, and 0.4 ms pulse duration) are within material specifications except for the magnet cage, where a redesign may be necessary. To assess the upgrade of the Linac4 source for operation in the high-power operation mode of the Superconducting Proton Linac (SPL), an extrapolation of the heat load toward 100 kW rf power, 50 Hz repetition rate, and 0.4 ms pulse duration has been performed. The results indicate that a significant improvement of the source cooling is required to allow for operation in the high-power mode of SPL.

  1. Finite element thermal study of the Linac4 plasma generator

    Energy Technology Data Exchange (ETDEWEB)

    Faircloth, D. [STFC, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX (United Kingdom); Kronberger, M.; Kuechler, D.; Lettry, J.; Scrivens, R. [BE-ABP, Hadron Sources and Linacs, CERN, CH-1211 Geneva (Switzerland)

    2010-02-15

    The temperature distribution and heat flow at equilibrium of the plasma generator of the rf-powered noncesiated Linac4 H{sup -} ion source have been studied with a finite element model. It is shown that the equilibrium temperatures obtained in the Linac4 nominal operation mode (100 kW rf power, 2 Hz repetition rate, and 0.4 ms pulse duration) are within material specifications except for the magnet cage, where a redesign may be necessary. To assess the upgrade of the Linac4 source for operation in the high-power operation mode of the Superconducting Proton Linac (SPL), an extrapolation of the heat load toward 100 kW rf power, 50 Hz repetition rate, and 0.4 ms pulse duration has been performed. The results indicate that a significant improvement of the source cooling is required to allow for operation in the high-power mode of SPL.

  2. Characterization of the gas-puff imploding plasma on the NRL Gamble II generator

    International Nuclear Information System (INIS)

    Stephanakis, S.J.; Boller, J.R.; Cooperstein, G.

    1984-01-01

    Recently, an experimental and theoretical effort has been undertaken at NRL aimed at contributing to understanding the physics of the implosion dynamics and of the resulting highly localized plasma pinch in such experiments. Supersonic nozzles producing a cylindrical gas flow provide the load for the Gamble II generator operating at the 1.5 TW level. The gas jet is preionized and then imploded to the axis by the machine electrical pulse in a very short time scale. During the implosion process, the attained kinetic energy is efficiently converted to plasma thermal energy and produces the desired radiation. Preliminary experimental results are presented from the study of the conditions necessary in order to efficiently couple such loads to the Gamble II generator. These results are correlated to existing scaling laws and are compared with theoretical models

  3. D Surface Generation from Aerial Thermal Imagery

    Science.gov (United States)

    Khodaei, B.; Samadzadegan, F.; Dadras Javan, F.; Hasani, H.

    2015-12-01

    Aerial thermal imagery has been recently applied to quantitative analysis of several scenes. For the mapping purpose based on aerial thermal imagery, high accuracy photogrammetric process is necessary. However, due to low geometric resolution and low contrast of thermal imaging sensors, there are some challenges in precise 3D measurement of objects. In this paper the potential of thermal video in 3D surface generation is evaluated. In the pre-processing step, thermal camera is geometrically calibrated using a calibration grid based on emissivity differences between the background and the targets. Then, Digital Surface Model (DSM) generation from thermal video imagery is performed in four steps. Initially, frames are extracted from video, then tie points are generated by Scale-Invariant Feature Transform (SIFT) algorithm. Bundle adjustment is then applied and the camera position and orientation parameters are determined. Finally, multi-resolution dense image matching algorithm is used to create 3D point cloud of the scene. Potential of the proposed method is evaluated based on thermal imaging cover an industrial area. The thermal camera has 640×480 Uncooled Focal Plane Array (UFPA) sensor, equipped with a 25 mm lens which mounted in the Unmanned Aerial Vehicle (UAV). The obtained results show the comparable accuracy of 3D model generated based on thermal images with respect to DSM generated from visible images, however thermal based DSM is somehow smoother with lower level of texture. Comparing the generated DSM with the 9 measured GCPs in the area shows the Root Mean Square Error (RMSE) value is smaller than 5 decimetres in both X and Y directions and 1.6 meters for the Z direction.

  4. Non-thermal atmospheric pressure HF plasma source: generation of nitric oxide and ozone for bio-medical applications

    Science.gov (United States)

    Kühn, S.; Bibinov, N.; Gesche, R.; Awakowicz, P.

    2010-01-01

    A new miniature high-frequency (HF) plasma source intended for bio-medical applications is studied using nitrogen/oxygen mixture at atmospheric pressure. This plasma source can be used as an element of a plasma source array for applications in dermatology and surgery. Nitric oxide and ozone which are produced in this plasma source are well-known agents for proliferation of the cells, inhalation therapy for newborn infants, disinfection of wounds and blood ozonation. Using optical emission spectroscopy, microphotography and numerical simulation, the gas temperature in the active plasma region and plasma parameters (electron density and electron distribution function) are determined for varied nitrogen/oxygen flows. The influence of the gas flows on the plasma conditions is studied. Ozone and nitric oxide concentrations in the effluent of the plasma source are measured using absorption spectroscopy and electro-chemical NO-detector at variable gas flows. Correlations between plasma parameters and concentrations of the particles in the effluent of the plasma source are discussed. By varying the gas flows, the HF plasma source can be optimized for nitric oxide or ozone production. Maximum concentrations of 2750 ppm and 400 ppm of NO and O3, correspondingly, are generated.

  5. Plasma Generator Using Spiral Conductors

    Science.gov (United States)

    Szatkowski, George N. (Inventor); Dudley, Kenneth L. (Inventor); Ticatch, Larry A. (Inventor); Smith, Laura J. (Inventor); Koppen, Sandra V. (Inventor); Nguyen, Truong X. (Inventor); Ely, Jay J. (Inventor)

    2016-01-01

    A plasma generator includes a pair of identical spiraled electrical conductors separated by dielectric material. Both spiraled conductors have inductance and capacitance wherein, in the presence of a time-varying electromagnetic field, the spiraled conductors resonate to generate a harmonic electromagnetic field response. The spiraled conductors lie in parallel planes and partially overlap one another in a direction perpendicular to the parallel planes. The geometric centers of the spiraled conductors define endpoints of a line that is non-perpendicular with respect to the parallel planes. A voltage source coupled across the spiraled conductors applies a voltage sufficient to generate a plasma in at least a portion of the dielectric material.

  6. Entropy generation method to quantify thermal comfort

    Science.gov (United States)

    Boregowda, S. C.; Tiwari, S. N.; Chaturvedi, S. K.

    2001-01-01

    The present paper presents a thermodynamic approach to assess the quality of human-thermal environment interaction and quantify thermal comfort. The approach involves development of entropy generation term by applying second law of thermodynamics to the combined human-environment system. The entropy generation term combines both human thermal physiological responses and thermal environmental variables to provide an objective measure of thermal comfort. The original concepts and definitions form the basis for establishing the mathematical relationship between thermal comfort and entropy generation term. As a result of logic and deterministic approach, an Objective Thermal Comfort Index (OTCI) is defined and established as a function of entropy generation. In order to verify the entropy-based thermal comfort model, human thermal physiological responses due to changes in ambient conditions are simulated using a well established and validated human thermal model developed at the Institute of Environmental Research of Kansas State University (KSU). The finite element based KSU human thermal computer model is being utilized as a "Computational Environmental Chamber" to conduct series of simulations to examine the human thermal responses to different environmental conditions. The output from the simulation, which include human thermal responses and input data consisting of environmental conditions are fed into the thermal comfort model. Continuous monitoring of thermal comfort in comfortable and extreme environmental conditions is demonstrated. The Objective Thermal Comfort values obtained from the entropy-based model are validated against regression based Predicted Mean Vote (PMV) values. Using the corresponding air temperatures and vapor pressures that were used in the computer simulation in the regression equation generates the PMV values. The preliminary results indicate that the OTCI and PMV values correlate well under ideal conditions. However, an experimental study

  7. Thermal efficiency of a non-transferred thermal plasma cannon

    International Nuclear Information System (INIS)

    Mercado, A.; Cota, G.; Merlo, L.; Pacheco, J.; Pena, R.; Cruz, A.

    1997-01-01

    This work shows a thermal efficiency research (ν) for a plasma torch in d.c. which was carried out through the realization of an energy balance around the system under consideration. The plasma torch is manufactured in copper with a tungsten incrustations in cathode. The gas used was argon and the gas fluxes were at the rank of 10 and 40 lt/min to the total pressure of 1.2 bar (1.1 atm). With these conditions it was worked with electric currents at the rank of 40 and 180 A. The data were collected through a data acquisition card which was programmed in Windows environment. (Author)

  8. Thermal plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Heberlein, J.; Pfender, E.

    1993-01-01

    Thermal plasmas, with temperatures up to and even exceeding 10 4 K, are capable of producing high density vapor phase precursors for the deposition of relatively thick films. Although this technology is still in its infancy, it will fill the void between the relatively slow deposition processes such as physical vapor deposition and the high rate thermal spray deposition processes. In this chapter, the present state-of-the-art of this field is reviewed with emphasis on the various types of reactors proposed for this emerging technology. Only applications which attracted particular attention, namely diamond and high T c superconducting film deposition, are discussed in greater detail. (orig.)

  9. Beat-wave generation of plasmons in semiconductor plasmas

    International Nuclear Information System (INIS)

    Berezhiani, V.I.; Mahajan, S.M.

    1995-08-01

    It is shown that in semiconductor plasmas, it is possible to generate large amplitude plasma waves by the beating of two laser beams with frequency difference close to the plasma frequency. For narrow gap seimconductors (for example n-type InSb), the system can simulate the physics underlying beat wave generation in relativistic gaseous plasmas

  10. Calibrated kallikrein generation in human plasma

    DEFF Research Database (Denmark)

    Biltoft, D; Sidelmann, J J; Olsen, L F

    2016-01-01

    generation method as a template. RESULTS: A suitable kallikrein specific fluorogenic substrate was identified (KM=0.91mM, kcat=19s(-1)), and kallikrein generation could be measured in undiluted plasma when silica was added as activator. Disturbing effects, including substrate depletion and the inner......-filter effect, however, affected the signal. These problems were corrected for by external calibration with α2-macroglobulin-kallikrein complexes. Selectivity studies of the substrate, experiments with FXII and PK depleted plasmas, and plasma with high or low complement C1-esterase inhibitor activity indicated...

  11. Thermal cycling characteristics of plasma synthesized mullite films

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, O.R.; Hou, P.Y.; Brown, I.G. [Lawrence Berkeley National Lab., CA (United States)

    1997-12-01

    The authors have developed a plasma-based technique for the synthesis of mullite and mullite-like films on silicon carbide substrate material. The method, which they refer to as MePIIID (for Metal Plasma Immersion Ion Implantation and Deposition), uses two vacuum arc plasma sources and simultaneous pulse biasing of the substrate in a low pressure oxygen atmosphere. The Al:Si ratio can be controlled via the separate plasma guns, and the film adhesion, structure and morphology can be controlled via the ion energy which in turn is controlled by the pulse bias voltage. The films are amorphous as-deposited, and crystalline mullite is formed by subsequent annealing at 1000 C for 2 hours in air. Adhesion between the aluminum-silicon oxide film and the substrate increases after this first annealing. They have tested the behavior of films when subjected to repetitive thermal cycling between room temperature and 1100 C, and found that the films retain their adhesion and quality. Here they review the plasma synthesis technique and the characteristics of the mullite films prepared in this way, and summarize the status of the thermal cycling experiments.

  12. Thermal Conductivity Analysis and Lifetime Testing of Suspension Plasma-Sprayed Thermal Barrier Coatings

    Directory of Open Access Journals (Sweden)

    Nicholas Curry

    2014-08-01

    Full Text Available Suspension plasma spraying (SPS has become an interesting method for the production of thermal barrier coatings for gas turbine components. The development of the SPS process has led to structures with segmented vertical cracks or column-like structures that can imitate strain-tolerant air plasma spraying (APS or electron beam physical vapor deposition (EB-PVD coatings. Additionally, SPS coatings can have lower thermal conductivity than EB-PVD coatings, while also being easier to produce. The combination of similar or improved properties with a potential for lower production costs makes SPS of great interest to the gas turbine industry. This study compares a number of SPS thermal barrier coatings (TBCs with vertical cracks or column-like structures with the reference of segmented APS coatings. The primary focus has been on lifetime testing of these new coating systems. Samples were tested in thermo-cyclic fatigue at temperatures of 1100 °C for 1 h cycles. Additional testing was performed to assess thermal shock performance and erosion resistance. Thermal conductivity was also assessed for samples in their as-sprayed state, and the microstructures were investigated using SEM.

  13. Multi-Directional Optical Diagnostics of Thermal Plasma Jets

    Czech Academy of Sciences Publication Activity Database

    Hlína, Jan; Chvála, František; Šonský, Jiří; Gruber, Jan

    2008-01-01

    Roč. 19, č. 1 (2008), s. 1-6 ISSN 0957-0233 R&D Projects: GA ČR(CZ) GA202/05/0728 Institutional research plan: CEZ:AV0Z20570509 Keywords : thermal plasma jet * optical diagnostics * Radon transform Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.493, year: 2008

  14. Beat-wave generation of plasmons in semiconductor plasmas

    International Nuclear Information System (INIS)

    Berezhiani, V.I.; Mahajan, S.M.

    1995-08-01

    It is shown that in semiconductor plasmas, it is possible to generate large amplitude plasma waves by the beating of two laser beams with frequency difference close to the plasma frequency. For narrow gap semiconductor (for example n-type InSb), the system can simulate the physics underlying beat wave generation in relativistic gaseous plasmas. (author). 7 refs

  15. Timescale and magnitude of plasma thermal energy loss before and during disruptions in JET

    International Nuclear Information System (INIS)

    Riccardo, V.; Loarte, A.

    2005-01-01

    In this paper we analyse and discuss the thermal energy loss dynamics before and during JET disruptions that occurred between 2002 and 2004 in discharges which reached >4.5 MJ of thermal energy. We observe the slow thermal energy transients with diamagnetic loops and the fast ones with electron cyclotron emission and soft x-ray diagnostics. For most disruption types in JET, the plasma thermal energy at the time of the thermal quench is substantially less than that of the full performance plasma, typically in the range of 10-50% depending on plasma conditions and disruption type. The exceptions to this observation are disruptions in plasmas with a strong internal transport barrier (ITB) and in discharges terminating in a pure vertical displacement event, in which the plasma conserves a very high energy content up to the thermal quench. These disruption types are very sudden, leaving little scope for the combined action of soft plasma landing strategies and intrinsic performance degradation, both requiring >500 ms to be effective, to decrease the available thermal energy. The characteristic time for the loss of energy from the main plasma towards the PFCs in the thermal quench of JET disruptions is in the range 0.05-3.0 ms. The shortest timescales are typical of disruptions caused by excessive pressure peaking in ITB discharges. The available thermal energy fraction and thermal quench duration observed in JET can be processed (with due caution) into estimates for the projected PFC lifetime of the ITER target

  16. Optical plasma torch electron bunch generation in plasma wakefield accelerators

    Directory of Open Access Journals (Sweden)

    G. Wittig

    2015-08-01

    Full Text Available A novel, flexible method of witness electron bunch generation in plasma wakefield accelerators is described. A quasistationary plasma region is ignited by a focused laser pulse prior to the arrival of the plasma wave. This localized, shapeable optical plasma torch causes a strong distortion of the plasma blowout during passage of the electron driver bunch, leading to collective alteration of plasma electron trajectories and to controlled injection. This optically steered injection is more flexible and faster when compared to hydrodynamically controlled gas density transition injection methods.

  17. The Role of Higher-Order Modes on the Electromagnetic Whistler-Cyclotron Wave Fluctuations of Thermal and Non-Thermal Plasmas

    Science.gov (United States)

    Vinas, Adolfo F.; Moya, Pablo S.; Navarro, Roberto; Araneda, Jamie A.

    2014-01-01

    Two fundamental challenging problems of laboratory and astrophysical plasmas are the understanding of the relaxation of a collisionless plasmas with nearly isotropic velocity distribution functions and the resultant state of nearly equipartition energy density with electromagnetic plasma turbulence. Here, we present the results of a study which shows the role that higher-order-modes play in limiting the electromagnetic whistler-like fluctuations in a thermal and non-thermal plasma. Our main results show that for a thermal plasma the magnetic fluctuations are confined by regions that are bounded by the least-damped higher order modes. We further show that the zone where the whistler-cyclotron normal modes merges the electromagnetic fluctuations shifts to longer wavelengths as the beta(sub e) increases. This merging zone has been interpreted as the beginning of the region where the whistler-cyclotron waves losses their identity and become heavily damped while merging with the fluctuations. Our results further indicate that in the case of nonthermal plasmas, the higher-order modes do not confine the fluctuations due to the effective higher-temperature effects and the excess of suprathermal plasma particles. The analysis presented here considers the second-order theory of fluctuations and the dispersion relation of weakly transverse fluctuations, with wave vectors parallel to the uniform background magnetic field, in a finite temperature isotropic bi-Maxwellian and Tsallis-kappa-like magnetized electron-proton plasma. Our results indicate that the spontaneously emitted electromagnetic fluctuations are in fact enhanced over these quasi modes suggesting that such modes play an important role in the emission and absorption of electromagnetic fluctuations in thermal or quasi-thermal plasmas.

  18. A universal mirror wave-mode threshold condition for non-thermal space plasma environments

    Directory of Open Access Journals (Sweden)

    M. P. Leubner

    2002-01-01

    Full Text Available Magnetic fluctuations are recognized in a large variety of space plasmas by increasingly high resolution, in situ observations as mirror wave mode structures. A typical requirement for the excitation of mirror modes is a dominant perpendicular pressure in a high-beta plasma environment. Contrary, we demonstrate from a realistic kinetic analysis how details of the velocity space distributions are of considerable significance for the instability threshold. Introducing the most common characteristics of observed ion and electron distributions by a mixed suprathermal-loss-cone, we derive a universal mirror instability criterion from an energy principle for collisionless plasmas. As a result, the transition from two temperature Maxwellians to realistic non-thermal features provides a strong source for the generation of mirror wave mode activity, reducing drastically the instability threshold. In particular, a number of space-related examples illuminate how the specific structure of the velocity space distribution dominates as a regulating excitation mechanism over the effects related to changes in the plasma parameters.

  19. Using plasma-fuel systems at Eurasian coal-fired thermal power stations

    Science.gov (United States)

    Karpenko, E. I.; Karpenko, Yu. E.; Messerle, V. E.; Ustimenko, A. B.

    2009-06-01

    The development of plasma technology for igniting solid fuels at coal-fired thermal power stations in Russia, Kazakhstan, China, and other Eurasian countries is briefly reviewed. Basic layouts and technical and economic characteristics of plasma-fuel systems installed in different coal-fired boiles are considered together with some results from using these systems at coal-fired thermal power stations.

  20. D.C.-arc plasma generator for nonequilibrium plasmachemical processes

    International Nuclear Information System (INIS)

    Kvaltin, J.

    1990-06-01

    The analysis is made of the conditions for generation of nonequilibrium plasma in a plasmachemical reactor, and the design is described of a d.c. arc plasma generator based on the integral criterion. Results of measuring potentials on the plasma column of this generator are presented. (author)

  1. Flux compression generators as plasma compression power sources

    International Nuclear Information System (INIS)

    Fowler, C.M.; Caird, R.S.; Erickson, D.J.; Freeman, B.L.; Thomson, D.B.; Garn, W.B.

    1979-01-01

    A survey is made of applications where explosive-driven magnetic flux compression generators have been or can be used to directly power devices that produce dense plasmas. Representative examples are discussed that are specific to the theta pinch, the plasma gun, the dense plasma focus and the Z pinch. These examples are used to illustrate the high energy and power capabilities of explosive generators. An application employing a rocket-borne, generator-powered plasma gun emphasizes the size and weight potential of flux compression power supplies. Recent results from a local effort to drive a dense plasma focus are provided. Imploding liners ae discussed in the context of both the theta and Z pinches

  2. Resonant and hollow beam generation of plasma channels

    International Nuclear Information System (INIS)

    Alexeev, I.; Kim, K.Y.; Fan, J.; Parra, E.; Milchberg, H.M.; Margolin, L.Ya.; Pyatnitskii, L.N.

    2001-01-01

    We report two variations on plasma channel generation using the propagation of intense Bessel beams. In the first experiment, the propagation of a high intensity Bessel beam in neutral gas is observed to give rise to resonantly enhanced plasma channel generation, resulting from resonant self-trapping of the beam and enhanced laser-plasma heating. In the second experiment, a high power, hollow Bessel beam (J 5 ) is produced and the optical breakdown of a gas target and the generation of a tubular plasma channel with such a beam is realized for the first time. Hydrodynamic simulations of the laser-plasma interaction of are in good agreement with the results of both experiments

  3. Analytical method for thermal stress analysis of plasma facing materials

    Science.gov (United States)

    You, J. H.; Bolt, H.

    2001-10-01

    The thermo-mechanical response of plasma facing materials (PFMs) to heat loads from the fusion plasma is one of the crucial issues in fusion technology. In this work, a fully analytical description of the thermal stress distribution in armour tiles of plasma facing components is presented which is expected to occur under typical high heat flux (HHF) loads. The method of stress superposition is applied considering the temperature gradient and thermal expansion mismatch. Several combinations of PFMs and heat sink metals are analysed and compared. In the framework of the present theoretical model, plastic flow and the effect of residual stress can be quantitatively assessed. Possible failure features are discussed.

  4. Analytical method for thermal stress analysis of plasma facing materials

    International Nuclear Information System (INIS)

    You, J.H.; Bolt, H.

    2001-01-01

    The thermo-mechanical response of plasma facing materials (PFMs) to heat loads from the fusion plasma is one of the crucial issues in fusion technology. In this work, a fully analytical description of the thermal stress distribution in armour tiles of plasma facing components is presented which is expected to occur under typical high heat flux (HHF) loads. The method of stress superposition is applied considering the temperature gradient and thermal expansion mismatch. Several combinations of PFMs and heat sink metals are analysed and compared. In the framework of the present theoretical model, plastic flow and the effect of residual stress can be quantitatively assessed. Possible failure features are discussed

  5. Operational features and air plasma characteristics of a thermal plasma torch with hollow electrodes

    International Nuclear Information System (INIS)

    Hur, Min; Kim, Keun Su; Hong, Sang Hee

    2003-01-01

    The operational features and thermal plasma characteristics of a plasma torch with hollow electrodes are investigated based on their dependence on input current, gas flow rate and electrode diameter when air is used as a plasma gas. A plasma torch with a hollow cathode and anode has been designed and fabricated, and the arc voltages and thermal efficiencies are measured from its discharge. The newly modified similarity criteria are derived from the measured data related to torch performances. From the fact that these criteria successfully describe both the arc voltage and thermal efficiency behaviour of the torch, depending on its operating and geometrical parameters, it is proved that they can be usefully applied to the design and operation of high power torches. For the numerical modelling of the interior region of the torch, a cold flow analysis is employed along with a simplified balance equation of the Lorentz and gas dynamic drag forces in order to determine a cathode spot position on the cathode surface. The validity of this method is confirmed by comparison of the calculated and measured net powers. As a practically useful result of this analysis, carried out through this numerical and experimental work, it is suggested that low input current, high gas flow rate and relatively large electrode diameter are more favourable as appropriate operating conditions of the torch for the efficient treatment of hazardous organic wastes

  6. Plasma diagnostic techniques in thermal-barrier tandem-mirror fusion experiments

    International Nuclear Information System (INIS)

    Silver, E.H.; Clauser, J.F.; Carter, M.R.; Failor, B.H.; Foote, J.H.; Hornady, R.S.; James, R.A.; Lasnier, C.J.; Perkins, D.E.

    1986-01-01

    We review two classes of plasma diagnostic techniques used in thermal-barrier tandem-mirror fusion experiments. The emphasis of the first class is to study mirror-trapped electrons at the thermal-barrier location. The focus of the second class is to measure the spatial and temporal behavior of the plasma space potential at various axial locations. The design and operation of the instruments in these two categories are discussed and data that are representative of their performance is presented

  7. Thermal Fatigue Behavior of Air-Plasma Sprayed Thermal Barrier Coating with Bond Coat Species in Cyclic Thermal Exposure

    Directory of Open Access Journals (Sweden)

    Ungyu Paik

    2013-08-01

    Full Text Available The effects of the bond coat species on the delamination or fracture behavior in thermal barrier coatings (TBCs was investigated using the yclic thermal fatigue and thermal-shock tests. The interface microstructures of each TBC showed a good condition without cracking or delamination after flame thermal fatigue (FTF for 1429 cycles. The TBC with the bond coat prepared by the air-plasma spray (APS method showed a good condition at the interface between the top and bond coats after cyclic furnace thermal fatigue (CFTF for 1429 cycles, whereas the TBCs with the bond coats prepared by the high-velocity oxygen fuel (HVOF and low-pressure plasma spray (LPPS methods showed a partial cracking (and/or delamination and a delamination after 780 cycles, respectively. The TBCs with the bond coats prepared by the APS, HVOF and LPPS methods were fully delaminated (>50% after 159, 36, and 46 cycles, respectively, during the thermal-shock tests. The TGO thickness in the TBCs was strongly dependent on the both exposure time and temperature difference tested. The hardness values were found to be increased only after the CFTF, and the TBC with the bond coat prepared by the APS showed the highest adhesive strength before and after the FTF.

  8. Influence of non-thermal plasma on structural and electrical properties of globular and nanostructured conductive polymer polypyrrole in water suspension.

    Science.gov (United States)

    Galář, Pavel; Khun, Josef; Kopecký, Dušan; Scholtz, Vladimír; Trchová, Miroslava; Fučíková, Anna; Jirešová, Jana; Fišer, Ladislav

    2017-11-08

    Non-thermal plasma has proved its benefits in medicine, plasma assisted polymerization, food industry and many other fields. Even though, the ability of non-thermal plasma to modify surface properties of various materials is generally known, only limited attention has been given to exploitations of this treatment on conductive polymers. Here, we show study of non-thermal plasma treatment on properties of globular and nanostructured polypyrrole in the distilled water. We observe that plasma presence over the suspension level doesn't change morphology of the polymer (shape), but significantly influences its elemental composition and physical properties. After 60 min of treatment, the relative concentration of chloride counter ions decreased approximately 3 and 4 times for nanostructured and globular form, respectively and concentration of oxygen increased approximately 3 times for both forms. Simultaneously, conductivity decrease (14 times for globular and 2 times for nanostructured one) and changes in zeta potential characteristics of both samples were observed. The modification evolution was dominated by multi-exponential function with time constants having values approximately 1 and 10 min for both samples. It is expected that these time constants are related to two modification processes connected to direct presence of the spark and to long-lived species generated by the plasma.

  9. Thermal conductivity of plasma modified polyethylene terephthalate and polyamide-6 layers

    Directory of Open Access Journals (Sweden)

    G. Kalacska

    2016-05-01

    Full Text Available Tribological performance of the materials greatly depends on the temperature of the contacting zones and surfaces and hence on the heat conducting behaviour of the materials. Heat conduction of polymers is, however, greatly affected even by a very narrow (few tens of nm modified layer formed on the surface after subjecting the polymer to plasma treatment. In this article the heat flow inhibiting properties of plasma modified surface layers were investigated on polyethylene terephthalate (PET and polyamide-6 (PA6 engineering polymers. Nitrogen Plasma Immersion Ion Implantation gave rise to compositional and structural changes of the polymers in a depth of 110 nm. It was found that even this thin layer exhibited significant heat flow inhibiting effect. The modified layer considerably decreased the thermal conductivity coefficient of the treated polymer and resulted in a reduced heat transmission for PET and PA6 by 33 and 28%, respectively. This new information supports and is in accordance with the former tribological results about extra friction heat generation experienced under NPIII surface layer of PA6 and PET during dry sliding.

  10. An amplitude modulated radio frequency plasma generator

    Science.gov (United States)

    Lei, Fan; Li, Xiaoping; Liu, Yanming; Liu, Donglin; Yang, Min; Xie, Kai; Yao, Bo

    2017-04-01

    A glow discharge plasma generator and diagnostic system has been developed to study the effects of rapidly variable plasmas on electromagnetic wave propagation, mimicking the plasma sheath conditions encountered in space vehicle reentry. The plasma chamber is 400 mm in diameter and 240 mm in length, with a 300-mm-diameter unobstructed clear aperture. Electron densities produced are in the mid 1010 electrons/cm3. An 800 W radio frequency (RF) generator is capacitively coupled through an RF matcher to an internally cooled stainless steel electrode to form the plasma. The RF power is amplitude modulated by a waveform generator that operates at different frequencies. The resulting plasma contains electron density modulations caused by the varying power levels. A 10 GHz microwave horn antenna pair situated on opposite sides of the chamber serves as the source and detector of probe radiation. The microwave power feed to the source horn is split and one portion is sent directly to a high-speed recording oscilloscope. On mixing this with the signal from the pickup horn antenna, the plasma-induced phase shift between the two signals gives the path-integrated electron density with its complete time dependent variation. Care is taken to avoid microwave reflections and extensive shielding is in place to minimize electronic pickup. Data clearly show the low frequency modulation of the electron density as well as higher harmonics and plasma fluctuations.

  11. Spectral characteristics of a relativistic plasma microwave generator

    International Nuclear Information System (INIS)

    Kuzelev, M.V.; Loza, O.T.; Ponomarev, A.V.; Rukhadze, A.A.; Strelkov, P.S.; Ul'yanov, D.K.; Shkvarunets, A.G.

    1996-01-01

    The radiation spectrum of a broad-band relativistic plasma microwave generator, in which a hollow relativistic electron beam is injected into a plasma waveguide consisting of a hollow plasma within a round metallic waveguide is measured experimentally. The radiation spectrum is measured using a wide-aperture calorimetric spectrometer in the frequency range 3-32 GHz. The influence of the plasma density and the beam-plasma gap on the radiation spectrum is investigated. The amplification of the noise electromagnetic radiation when a relativistic electron beam is injected into the plasma waveguide is calculated on the basis of the nonlinear theory. The theory predicts passage from a one-particle generation regime to a collective regime and narrowing of the radiation spectrum as the plasma density and the gap between the hollow beam and the plasma increases. A comparison of the measurement results with the nonlinear theory accounts for several features of the measured spectrum. However, the predicted change in the generation regimes is not observed experimentally. Qualitative arguments are advanced, which explain the observed phenomena and call for further theoretical and experimental research, are advanced

  12. The thermal evolution of targets under plasma focus pulsed ion implantation

    International Nuclear Information System (INIS)

    Sanchez, G.; Feugeas, J.

    1997-01-01

    Pulsed ion beam implantation with plasma focus has proved to be an effective method of metal surface treatment for tribological purposes. Nevertheless, the pulsed nature and the continuous energy spectrum of the ion beams differ from those of the standard ion implantation processes. In this paper a model of the thermal evolution of the surface layers of stainless steel, titanium and copper, during and after nitrogen and argon ion beam incidence, is presented using the finite-difference method. In the calculations, the geometry and physical characteristics of the ion beams, the single-ion-solid interaction process and the thermal properties of the materials were used. The results showed a strong thermal effect consisting in the generation of transitory heating slopes and heating speeds as high as ∼3600 K μm -1 and ∼40 K ns -1 respectively, with maximum temperatures that can reach even the material evaporation point at the surface layers. The cooling down process, through the thermal conduction mechanism at the target bulk, turns out to be fast enough to produce the complete thermal relaxation of the target in only a few microseconds after the end of the ion beam incidence. The results presented are contrasted with experiments performed in similar conditions to those used in the numerical model. (Author)

  13. Streaming metal plasma generation by vacuum arc plasma guns

    International Nuclear Information System (INIS)

    MacGill, R.A.; Dickinson, M.R.; Anders, A.; Monteiro, O.R.; Brown, I.G.

    1998-01-01

    We have developed several different embodiments of repetitively pulsed vacuum arc metal plasma gun, including miniature versions, multicathode versions that can produce up to 18 different metal plasma species between which one can switch, and a compact high-duty cycle well-cooled version, as well as a larger dc gun. Plasma guns of this kind can be incorporated into a vacuum arc ion source for the production of high-energy metal ion beams, or used as a plasma source for thin film formation and for metal plasma immersion ion implantation and deposition. The source can also be viewed as a low-energy metal ion source with ion drift velocity in the range 20 - 200 eV depending on the metal species used. Here we describe the plasma sources that we have developed, the properties of the plasma generated, and summarize their performance and limitations. copyright 1998 American Institute of Physics

  14. Hollow laser plasma self-confined microjet generation

    Science.gov (United States)

    Sizyuk, Valeryi; Hassanein, Ahmed; CenterMaterials under Extreme Environment Team

    2017-10-01

    Hollow laser beam produced plasma (LPP) devices are being used for the generation of the self-confined cumulative microjet. Most important place by this LPP device construction is achieving of an annular distribution of the laser beam intensity by spot. An integrated model is being developed to detailed simulation of the plasma generation and evolution inside the laser beam channel. The model describes in two temperature approximation hydrodynamic processes in plasma, laser absorption processes, heat conduction, and radiation energy transport. The total variation diminishing scheme in the Lax-Friedrich formulation for the description of plasma hydrodynamic is used. Laser absorption and radiation transport models on the base of Monte Carlo method are being developed. Heat conduction part on the implicit scheme with sparse matrixes using is realized. The developed models are being integrated into HEIGHTS-LPP computer simulation package. The integrated modeling of the hollow beam laser plasma generation showed the self-confinement and acceleration of the plasma microjet inside the laser channel. It was found dependence of the microjet parameters including radiation emission on the hole and beam radiuses ratio. This work is supported by the National Science Foundation, PIRE project.

  15. Novel methods of ozone generation by micro-plasma concept

    Energy Technology Data Exchange (ETDEWEB)

    Fateev, A.; Chiper, A.; Chen, W.; Stamate, E.

    2008-02-15

    The project objective was to study the possibilities for new and cheaper methods of generating ozone by means of different types of micro-plasma generators: DBD (Dielectric Barrier Discharge), MHCD (Micro-Hollow Cathode Discharge) and CPED (Capillary Plasma Electrode Discharge). This project supplements another current project where plasma-based DeNOx is being studied and optimised. The results show potentials for reducing ozone generation costs by means of micro-plasmas but that further development is needed. (ln)

  16. Investigation and applications of a plasma generator

    International Nuclear Information System (INIS)

    Frere, Isabelle

    1992-01-01

    This work describes the experimental study of a plasma generator: a cylindrical or parallelepipedic rectangle cathode. A permanent magnet creates an axial magnetic field of a few hundred Gauss. A cold and abnormal glow discharge plasma is obtained. The experimental research on the correlation between the discharge parameters (electrode geometry, gas pressure, discharge voltage and current, magnetic field) of the discharge is presented. Another part of the text mentions some generator applications to surface treatment: evaporation, sputtering, surface modification of polymers by exposure to plasma. (author) [fr

  17. Steam generator thermal-hydraulics

    International Nuclear Information System (INIS)

    Inch, W.W.; Scott, D.A.; Carver, M.B.

    1980-01-01

    This paper discusses a code for detailed numerical modelling of steam generator thermal-hydraulics, and describes related experimental programs designed to promote in-depth understanding of three-dimensional two-phase flow. (auth)

  18. Thermal Plasma Synthesis of Crystalline Gallium Nitride Nanopowder from Gallium Nitrate Hydrate and Melamine

    Directory of Open Access Journals (Sweden)

    Tae-Hee Kim

    2016-02-01

    Full Text Available Gallium nitride (GaN nanopowder used as a blue fluorescent material was synthesized by using a direct current (DC non-transferred arc plasma. Gallium nitrate hydrate (Ga(NO33∙xH2O was used as a raw material and NH3 gas was used as a nitridation source. Additionally, melamine (C3H6N6 powder was injected into the plasma flame to prevent the oxidation of gallium to gallium oxide (Ga2O3. Argon thermal plasma was applied to synthesize GaN nanopowder. The synthesized GaN nanopowder by thermal plasma has low crystallinity and purity. It was improved to relatively high crystallinity and purity by annealing. The crystallinity is enhanced by the thermal treatment and the purity was increased by the elimination of residual C3H6N6. The combined process of thermal plasma and annealing was appropriate for synthesizing crystalline GaN nanopowder. The annealing process after the plasma synthesis of GaN nanopowder eliminated residual contamination and enhanced the crystallinity of GaN nanopowder. As a result, crystalline GaN nanopowder which has an average particle size of 30 nm was synthesized by the combination of thermal plasma treatment and annealing.

  19. State of the art in medical applications using non-thermal atmospheric pressure plasma

    Science.gov (United States)

    Tanaka, Hiromasa; Ishikawa, Kenji; Mizuno, Masaaki; Toyokuni, Shinya; Kajiyama, Hiroaki; Kikkawa, Fumitaka; Metelmann, Hans-Robert; Hori, Masaru

    2017-12-01

    Plasma medical science is a novel interdisciplinary field that combines studies on plasma science and medical science, with the anticipation that understanding the scientific principles governing plasma medical science will lead to innovations in the field. Non-thermal atmospheric pressure plasma has been used for medical treatments, such as for cancer, blood coagulation, and wound healing. The interactions that occur between plasma and cells/tissues have been analyzed extensively. Direct and indirect treatment of cells with plasma has broadened the applications of non-thermal atmospheric pressure plasma in medicine. Examples of indirect treatment include plasma-assisted immune-therapy and plasma-activated medium. Controlling intracellular redox balance may be key in plasma cancer treatment. Animal studies are required to test the effectiveness and safety of these treatments for future clinical applications.

  20. Properties of thermal air plasma with admixing of copper and carbon

    International Nuclear Information System (INIS)

    Fesenko, S; Veklich, A; Boretskij, V; Cressault, Y; Gleizes, A; Teulet, Ph

    2014-01-01

    This paper deals with investigations of air plasma with admixing of copper and carbon. Model plasma source unit with real breaking arc was used for the simulation of real discharges, which can be occurred during sliding of Cu-C composite electrodes on copper wire at electromotive vehicles. The complex technique of plasma property studies is developed. From one hand, the radial profiles of temperature and electron density in plasma of electric arc discharge in air between Cu-C composite and copper electrodes in air flow were measured by optical spectroscopy techniques. From another hand, the radial profiles of electric conductivity of plasma mixture were calculated by solution of energy balance equation. It was assumed that the thermal conductivity of air plasma is not depending on copper or carbon vapor admixtures. The electron density is obtained from electric conductivity profiles by calculation in assumption of local thermodynamic equilibrium in plasma. Computed in such way radial profiles of electron density in plasma of electric arc discharge in air between copper electrodes were compared with experimentally measured profiles. It is concluded that developed techniques of plasma diagnostics can be reasonably used in investigations of thermal plasma with copper and carbon vapors

  1. Thermoelectric power generator for variable thermal power source

    Science.gov (United States)

    Bell, Lon E; Crane, Douglas Todd

    2015-04-14

    Traditional power generation systems using thermoelectric power generators are designed to operate most efficiently for a single operating condition. The present invention provides a power generation system in which the characteristics of the thermoelectrics, the flow of the thermal power, and the operational characteristics of the power generator are monitored and controlled such that higher operation efficiencies and/or higher output powers can be maintained with variably thermal power input. Such a system is particularly beneficial in variable thermal power source systems, such as recovering power from the waste heat generated in the exhaust of combustion engines.

  2. Thermalization of mini-jets in a quark–gluon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Iancu, Edmond, E-mail: edmond.iancu@cea.fr; Wu, Bin, E-mail: bin.wu.phys@gmail.com [Institut de Physique Théorique, CEA Saclay, CNRS UMR 3681, F-91191 Gif-sur-Yvette (France); Department of Physics, The Ohio State University, Columbus, OH 43210 (United States)

    2016-12-15

    We present the complete physical picture for the evolution of a high-energy jet propagating through a weakly-coupled quark-gluon plasma (QGP) by analytical and numerical investigation of thermalization of the soft components of the jet. Our results support the following physical picture: the leading particle emits a significant number of mini-jets which promptly evolve via multiple branching and thus degrade into a myriad of soft gluons, with energies of the order of the medium temperature T. Via elastic collisions with the medium constituents, these soft gluons relax to local thermal equilibrium with the plasma over a time scale which is considerably shorter than the typical lifetime of the mini-jet. The thermalized gluons form a tail which lags behind the hard components of the jet. Together with the background QGP, they behave hydrodynamically.

  3. Treatment of hazardous wastes by DC thermal plasma arc discharge

    International Nuclear Information System (INIS)

    Toru, Iwao; Yafang, Liu; Furuta, N.; Tsuginori, Inaba

    2001-01-01

    The temperature of the DC thermal plasma arc discharge is discussed, and examples of the waste treatment for the inorganic compounds such as fly ash, asbestos, and for the organic compounds such as the toxic dioxines and TBT by using the DC plasma arc discharge are shown. In addition, the plasma treatment by using a radiant power emitted from the DC plasma arc discharge is also shown as another new kind of ones. (authors)

  4. Radioactive waste combustion-vitrification under arc plasma: thermal and dynamic modelling

    International Nuclear Information System (INIS)

    Barthelemy, B.

    2003-06-01

    This thesis concerns the thermal and dynamic modelling for a combustion/vitrification process of surrogate radioactive waste under transferred arc plasma. The writer presents the confinement processes for radioactive waste using arc plasma and the different software used to model theses processes. This is followed by a description of our experimental equipment including a plasma arc reactor and an inductive system allowing the homogenization of glass temperature. A combustion/vitrification test is described. Thermal and material balances were discussed. The temperature fields of plasma arc and the glass frit conductivity are measured. Finally, the writer describes and clarifies the equations solved for the simulations of the electrically plasma arc and the glass melting including the thin layer of glass frit coating the crucible cold walls. The modelling results are presented in the form of spatial distribution of temperature, velocity and voluminal power... (author)

  5. Radioactive waste combustion / vitrification under arc plasma: thermal and dynamic modelling

    International Nuclear Information System (INIS)

    Barthelemy, B.

    2003-01-01

    This thesis concerns the thermal and dynamic modelling for a combustion/vitrification process of surrogate radioactive waste under transferred arc plasma. The writer presents the confinement processes for radioactive waste using arc plasma and the different software used to model theses processes. This is followed by a description of our experimental equipment including a plasma arc reactor and an inductive system allowing the homogenization of glass temperature. A combustion/vitrification test is described. Thermal and material balances were discussed. The temperature fields of plasma arc and the glass frit conductivity are measured. Finally, the writer describes and clarifies the equations solved for the simulations of the electrically plasma arc and the glass melting including the thin layer of glass frit coating the crucible cold walls. The modelling results are presented in the form of spatial distribution of temperature, velocity and volume power... (author)

  6. Formation of thermal eddies during rf heating of plasma

    International Nuclear Information System (INIS)

    Motley, R.W.; Hooke, W.M.; Anania, G.

    1979-07-01

    Moderate power (approx.1 kW) excitation of lower hybrid waves in a linear plasma column is found to increase the reflectivity of the phased waveguide exciter and to change the vertical position of the resonance cone. Probing of the plasma near the mouth of the waveguide reveals that the increased reflection results from an undulation in the plasma surface. We present evidence that this surface distortion is driven by thermal eddies associated with asymmetrical electron heating

  7. Thermal analysis of the in-vessel components of the ITER plasma-position reflectometry

    Energy Technology Data Exchange (ETDEWEB)

    Quental, P. B., E-mail: pquental@ipfn.tecnico.ulisboa.pt; Policarpo, H.; Luís, R.; Varela, P. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal)

    2016-11-15

    The ITER plasma position reflectometry system measures the edge electron density profile of the plasma, providing real-time supplementary contribution to the magnetic measurements of the plasma-wall distance. Some of the system components will be in direct sight of the plasma and therefore subject to plasma and stray radiation, which may cause excessive temperatures and stresses. In this work, thermal finite element analysis of the antenna and adjacent waveguides is conducted with ANSYS V17 (ANSYS® Academic Research, Release 17.0, 2016). Results allow the identification of critical temperature points, and solutions are proposed to improve the thermal behavior of the system.

  8. Thermal performances of molten salt steam generator

    International Nuclear Information System (INIS)

    Yuan, Yibo; He, Canming; Lu, Jianfeng; Ding, Jing

    2016-01-01

    Highlights: • Thermal performances of molten salt steam generator were experimentally studied. • Overall heat transfer coefficient reached maximum with optimal molten salt flow rate. • Energy efficiency first rose and then decreased with salt flow rate and temperature. • Optimal molten salt flow rate and temperature existed for good thermal performance. • High inlet water temperature benefited steam generating rate and energy efficiency. - Abstract: Molten salt steam generator is the key technology for thermal energy conversion from high temperature molten salt to steam, and it is used in solar thermal power station and molten salt reactor. A shell and tube type molten salt steam generator was set up, and its thermal performance and heat transfer mechanism were studied. As a coupling heat transfer process, molten salt steam generation is mainly affected by molten salt convective heat transfer and boiling heat transfer, while its energy efficiency is also affected by the heat loss. As molten salt temperature increased, the energy efficiency first rose with the increase of heat flow absorbed by water/steam, and then slightly decreased for large heat loss as the absorbed heat flow still rising. At very high molten salt temperature, the absorbed heat flow decreased as boiling heat transfer coefficient dropping, and then the energy efficiency quickly dropped. As the inlet water temperature increased, the boiling region in the steam generator remarkably expanded, and then the steam generation rate and energy efficiency both rose with the overall heat transfer coefficient increasing. As the molten salt flow rate increased, the wall temperature rose and the boiling heat transfer coefficient first increased and then decreased according to the boiling curve, so the overall heat transfer coefficient first increased and then decreased, and then the steam generation rate and energy efficiency of steam generator both had maxima.

  9. Atmospheric plasma generation for LCD panel cleaning

    Science.gov (United States)

    Kim, Gyu-Sik; Won, Chung-Yuen; Choi, Ju-Yeop; Yim, C. H.

    2007-12-01

    UV lamp systems have been used for cleaning of display panels of TFT LCD or Plasma Display Panel (PDP). However, the needs for high efficient cleaning and low cost made high voltage plasma cleaning techniques to be developed and to be improved. Dielectric-barrier discharges (DBDs), also referred to as barrier discharges or silent discharges have for a long time been exclusively related to ozone generation. In this paper, a 6kW high voltage plasma power supply system was developed for LCD cleaning. The -phase input voltage is rectified and then inverter system is used to make a high frequency pulse train, which is rectified after passing through a high-power transformer. Finally, bi-directional high voltage pulse switching circuits are used to generate the high voltage plasma. Some experimental results showed the usefulness of atmospheric plasma for LCD panel cleaning.

  10. Cascade generation in Al laser induced plasma

    Science.gov (United States)

    Nagli, Lev; Gaft, Michael; Raichlin, Yosef; Gornushkin, Igor

    2018-05-01

    We found cascade IR generation in Al laser induced plasma. This generation includes doublet transitions 3s 25s 2S1/2 → 3s24p 2P1/2,3/2 → 3s24s 2S1/2; corresponding to strong lines at 2110 and 2117 nm, and much weaker lines at 1312-1315 nm. The 3s25s2S 1/2 starting IR generation level is directly pumped from the 3s23p 2P3/2 ground level. The starting level for UV generation at 396.2 nm (transitions 3s24s 2S1/2 → 4p 2P3/2) is populated due to the fast collisional processes in the plasma plume. These differences led to different time and special dependences on the lasing in the IR and UV spectral range within the aluminum laser induced plasma.

  11. Reflection of oblique electron thermal modes in an inhomogeneous plasma

    International Nuclear Information System (INIS)

    Ohnuma, T.; Watanabe, T.; Sanuki, H.

    1980-04-01

    In an inhomogeneous magnetoplasma, reflection of an oblique electron thermal mode radiated from a local source is investigated experimentally and theoretically near the electron plasma frequency layer. The experimental observation of reflection in the lower plasma density region than the f sub(p)-layer is found to be in qualitative accord with the theoretical reflection, which is obtained from a kinetic theory in an inhomogeneous magnetoplasma. The reflection of the thermal mode is also compared with that of an electromagnetic mode at the f sub(p)-layer. (author)

  12. Statistics of turbulent structures in a thermal plasma jet

    Czech Academy of Sciences Publication Activity Database

    Hlína, Jan; Šonský, Jiří; Něnička, Václav; Zachar, Andrej

    2005-01-01

    Roč. 38, - (2005), s. 1760-1768 ISSN 0022-3727 R&D Projects: GA AV ČR(CZ) IAA1057202; GA ČR(CZ) GA202/05/0728 Institutional research plan: CEZ:AV0Z20570509 Keywords : turbulent structures * thermal plasma jet Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.957, year: 2005

  13. On-site SiH4 generator using hydrogen plasma generated in slit-type narrow gap

    Science.gov (United States)

    Takei, Norihisa; Shinoda, Fumiya; Kakiuchi, Hiroaki; Yasutake, Kiyoshi; Ohmi, Hiromasa

    2018-06-01

    We have been developing an on-site silane (SiH4) generator based on use of the chemical etching reaction between solid silicon (Si) and the high-density H atoms that are generated in high-pressure H2 plasma. In this study, we have developed a slit-type plasma source for high-efficiency SiH4 generation. High-density H2 plasma was generated in a narrow slit-type discharge gap using a 2.45 GHz microwave power supply. The plasma’s optical emission intensity distribution along the slit was measured and the resulting distribution was reflected by both the electric power distribution and the hydrogen gas flow. Because the Si etching rate strongly affects the SiH4 generation rate, the Si etching behavior was investigated with respect to variations in the experimental parameters. The weight etch rate increased monotonically with increasing input microwave power. However, the weight etch rate decreased with increasing H2 pressure and an increasing plasma gap. This reduction in the etch rate appears to be related to shrinkage of the plasma generation area because increased input power is required to maintain a constant plasma area with increasing H2 pressure and the increasing plasma gap. Additionally, the weight etch rate also increases with increasing H2 flow rate. The SiH4 generation rate of the slit-type plasma source was also evaluated using gas-phase Fourier transform infrared absorption spectroscopy and the material utilization efficiencies of both Si and the H2 gas for SiH4 gas formation were discussed. The main etch product was determined to be SiH4 and the developed plasma source achieved a SiH4 generation rate of 10 sccm (standard cubic centimeters per minute) at an input power of 900 W. In addition, the Si utilization efficiency exceeded 60%.

  14. Studying the non-thermal plasma jet characteristics and application on bacterial decontamination

    Science.gov (United States)

    Al-rawaf, Ali F.; Fuliful, Fadhil Khaddam; Khalaf, Mohammed K.; Oudah, Husham. K.

    2018-04-01

    Non-thermal atmospheric-pressure plasma jet represents an excellent approach for the decontamination of bacteria. In this paper, we want to improve and characterize a non-thermal plasma jet to employ it in processes of sterilization. The electrical characteristics was studied to describe the discharge of the plasma jet and the development of plasma plume has been characterized as a function of helium flow rate. Optical emission spectroscopy was employed to detect the active species inside the plasma plume. The inactivation efficiency of non-thermal plasma jet was evaluated against Staphylococcus aureus bacteria by measuring the diameter of inhibition zone and the number of surviving cells. The results presented that the plasma plume temperature was lower than 34° C at a flow rate of 4 slm, which will not cause damage to living tissues. The diameter of inhibition zone is directly extended with increased exposure time. We confirmed that the inactivation mechanism was unaffected by UV irradiation. In addition, we concluded that the major reasons for the inactivation process of bacteria is because of the action of the reactive oxygen and nitrogen species which formed from ambient air, while the charged particles played a minor role in the inactivation process.

  15. Electrode assemblies, plasma apparatuses and systems including electrode assemblies, and methods for generating plasma

    Science.gov (United States)

    Kong, Peter C; Grandy, Jon D; Detering, Brent A; Zuck, Larry D

    2013-09-17

    Electrode assemblies for plasma reactors include a structure or device for constraining an arc endpoint to a selected area or region on an electrode. In some embodiments, the structure or device may comprise one or more insulating members covering a portion of an electrode. In additional embodiments, the structure or device may provide a magnetic field configured to control a location of an arc endpoint on the electrode. Plasma generating modules, apparatus, and systems include such electrode assemblies. Methods for generating a plasma include covering at least a portion of a surface of an electrode with an electrically insulating member to constrain a location of an arc endpoint on the electrode. Additional methods for generating a plasma include generating a magnetic field to constrain a location of an arc endpoint on an electrode.

  16. Ion turbulence and thermal transport in laser-produced plasmas

    International Nuclear Information System (INIS)

    Barr, H.C.; Boyd, T.J.M.

    1982-01-01

    In the interaction of high-intensity lasers with target plasmas the transport of thermal energy from the region in which the radiation is absorbed, to the cold dense plasma in the interior of the target, is an issue of central importance. The role of ion turbulence as a flux limiter is addressed with particular regard to recent experiments in which target plasmas were irradiated by 1.06 μm neodymium laser light at irradiances of 10 15 W cm - 2 and greater. Saturation levels of the ion-acoustic turbulence driven by a combination of a suprathermal electron current and a heat flux are calculated on the basis of perturbed orbit theory. The levels of turbulence are found to be markedly lower than those commonly estimated from simple trapping arguments and too low to explain the thermal flux inhibition observed in the experiments used as a basis for the model. (author)

  17. Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species.

    Science.gov (United States)

    Arjunan, Krishna Priya; Friedman, Gary; Fridman, Alexander; Clyne, Alisa Morss

    2012-01-07

    Vascularization plays a key role in processes such as wound healing and tissue engineering. Non-thermal plasma, which primarily produces reactive oxygen species (ROS), has recently emerged as an efficient tool in medical applications including blood coagulation, sterilization and malignant cell apoptosis. Liquids and porcine aortic endothelial cells were treated with a non-thermal dielectric barrier discharge plasma in vitro. Plasma treatment of phosphate-buffered saline (PBS) and serum-free medium increased ROS concentration in a dose-dependent manner, with a higher concentration observed in serum-free medium compared with PBS. Species concentration inside cells peaked 1 h after treatment, followed by a decrease 3 h post treatment. Endothelial cells treated with a plasma dose of 4.2 J cm(-2) had 1.7 times more cells than untreated samples 5 days after plasma treatment. The 4.2 J cm(-2) plasma dose increased two-dimensional migration distance by 40 per cent compared with untreated control, while the number of cells that migrated through a three-dimensional collagen gel increased by 15 per cent. Tube formation was also enhanced by plasma treatment, with tube lengths in plasma-treated samples measuring 2.6 times longer than control samples. A fibroblast growth factor-2 (FGF-2) neutralizing antibody and ROS scavengers abrogated these angiogenic effects. These data indicate that plasma enhanced proliferation, migration and tube formation is due to FGF-2 release induced by plasma-produced ROS. Non-thermal plasma may be used as a potential tool for applying ROS in precise doses to enhance vascularization.

  18. Plasma driven neutron/gamma generator

    Science.gov (United States)

    Leung, Ka-Ngo; Antolak, Arlyn

    2015-03-03

    An apparatus for the generation of neutron/gamma rays is described including a chamber which defines an ion source, said apparatus including an RF antenna positioned outside of or within the chamber. Positioned within the chamber is a target material. One or more sets of confining magnets are also provided to create a cross B magnetic field directly above the target. To generate neutrons/gamma rays, the appropriate source gas is first introduced into the chamber, the RF antenna energized and a plasma formed. A series of high voltage pulses are then applied to the target. A plasma sheath, which serves as an accelerating gap, is formed upon application of the high voltage pulse to the target. Depending upon the selected combination of source gas and target material, either neutrons or gamma rays are generated, which may be used for cargo inspection, and the like.

  19. The plasma wake field excitation: Recent developments from thermal to quantum regime

    Science.gov (United States)

    Fedele, Renato; Tanjia, Fatema; de Nicola, Sergio; Jovanović, Dušan; Jovanović

    2013-12-01

    To describe the transverse nonlinear and collective self-consistent interaction of a long relativistic electron or positron beam with an unmagnetized plasma, a pair of coupled nonlinear differential equations were proposed by Fedele and Shukla in 1992 (Fedele, R. and Shukla, P. K. 1992a Phys. Rev. A 45, 4045). They were obtained within the quantum-like description provided by the thermal wave model and the theory of plasma wake field excitation. The pair of equations comprises a 2D Schrödinger-like equation for a complex wave function (whose squared modulus is proportional to beam density) and a Poisson-like equation for the plasma wake potential. The dispersion coefficient of the Schrödinger-like equation is proportional to the beam thermal emittance. More recently, Fedele-Shukla equations have been further applied to magnetized plasmas, and solutions were found in the form of nonlinear vortex states and ring solitons. They have been also applied to plasma focusing problems and extended from thermal to quantum regimes. We present here a review of the original approach, and subsequent developments.

  20. Pre-treating water with non-thermal plasma

    Science.gov (United States)

    Cho, Young I.; Fridman, Alexander; Rabinovich, Alexander; Cho, Daniel J.

    2017-07-04

    The present invention consists of a method of pre-treatment of adulterated water for distillation, including adulterated water produced during hydraulic fracturing ("fracking") of shale rock during natural gas drilling. In particular, the invention is directed to a method of treating adulterated water, said adulterated water having an initial level of bicarbonate ion in a range of about 250 ppm to about 5000 ppm and an initial level of calcium ion in a range of about 500 ppm to about 50,000 ppm, said method comprising contacting the adulterated water with a non-thermal arc discharge plasma to produce plasma treated water having a level of bicarbonate ion of less than about 100 ppm. Optionally, the plasma treated water may be further distilled.

  1. Thermal fatigue behavior of thermal barrier coatings by air plasma spray

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Han Sang; Kim, Eui Hyun [Korea Electric Power Research Institute, Daejeon (Korea, Republic of); Lee, Jung Hyuk [Korea Plant Service and Engineering Co. Ltd., Incheon (Korea, Republic of)

    2008-06-15

    Effects of top coat morphology and thickness on thermal fatigue behavior of Thermal Barrier Coatings (TBC) were investigated in this study. Thermal fatigue tests were conducted on three coating specimens with different top coat morphology and thickness, and then the test data were compared via microstructures, cycles to failure, and fracture surfaces. In the air plasma spray specimens (APS1, APS2), top coat were 200 and 300 {mu}m respectively. The thickness of top coat was about 700 {mu}m in the Perpendicular Cracked Specimen (PCS). Under thermal fatigue condition at 1,100 .deg. C, the cycles to top coat failure of APS1, APS2, and PCS were 350, 560 and 480 cycles, respectively. The cracks were initiated at the interface of top coat and Thermally Grown Oxide (TGO) and propagated into TGO or top coat as the number of thermal fatigue cycles increased. For the PCS specimen, additive cracks were initiated and propagated at the starting points of perpendicular cracks in the top coat. Also, the thickness of TGO and the decrease of aluminium concentration in bond coat do not affect the cycles to failure.

  2. Influence of Microstructure on Thermal Properties of Axial Suspension Plasma-Sprayed YSZ Thermal Barrier Coatings

    Czech Academy of Sciences Publication Activity Database

    Ganvir, A.; Curry, N.; Markocsan, N.; Nylen, P.; Joshi, S.; Vilémová, Monika; Pala, Zdeněk

    2016-01-01

    Roč. 25, 1-2 (2016), s. 202-212 ISSN 1059-9630. [ITSC 2015: International Thermal Spray Conference and Exposition. Long Beach, California, 11.05.2015-14.05.2015] Institutional support: RVO:61389021 Keywords : axial injection * column ar microstructure * porosity * suspension plasma spraying * thermal conductivity * thermal diffusivity Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 1.488, year: 2016 http://link.springer.com/article/10.1007%2Fs11666-015-0355-7

  3. Non-thermal plasma treatment diminishes fungal viability and up-regulates resistance genes in a plant host.

    Science.gov (United States)

    Panngom, Kamonporn; Lee, Sang Hark; Park, Dae Hoon; Sim, Geon Bo; Kim, Yong Hee; Uhm, Han Sup; Park, Gyungsoon; Choi, Eun Ha

    2014-01-01

    Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation) while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar) plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR) genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum) after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance.

  4. A model for steady-state large-volume plasma generation

    International Nuclear Information System (INIS)

    Uhm, H.S.; Miller, J.D.; Schneider, R.F.

    1991-01-01

    In this paper, a simple, new scheme to generate a uniform, steady-state, large-volume plasma is presented. The weakly magnetized plasma is created by direct ionization of the background gas by low-energy electrons generated from thermionic filaments. An annular arrangement of the filaments ensures a uniform plasma density in the radial direction as predicted by theory. Experiments have been performed to characterize the plasma generated in such a configuration. In order to explain the experimental observation, we develop a bulk plasma theory based on plasma transport via cross-field diffusion. As assumed in the theoretical model, the experimental measurements indicate a uniform plasma density along the axis. Both the theory and experiment indicate that the plasma density is a function of the square of the external magnetic field. The theory also predicts the plasma density to be proportional to the neutral density to the two-thirds power in agreement with the experimental data. We also observe the experimental data to agree remarkably well with theoretical prediction for a broad range of system parameters

  5. A high-voltage pulse generator for corona plasma generation

    NARCIS (Netherlands)

    Yan, K.; Heesch, van E.J.M.; Pemen, A.J.M.; Huijbrechts, P.A.H.J.; Gompel, van F.M.; Leuken, van H.E.M.; Matyas, Z.

    2002-01-01

    This paper discusses a high-voltage pulse generator for producing corona plasma. The generator consists of three resonant charging circuits, a transmission line transformer, and a triggered spark-gap switch. Voltage pulses in the order of 30-100 kV with a rise time of 10-20 ns, a pulse duration of

  6. Fabrication of TiC-TiO{sub 2} composite powders by thermal plasma oxidation of titanium carbide powder; Tanka chitan funmatsu no plasma sanka hanno ni yori seiseishita TiC-TiO{sub 2} fukugo funmatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ishigaki, T.; Li, Y.; Haneda, H. [National institute for Research Inorganic materials, Tsukuba (Japan); Kataoka, E. [Showa Cabot Supermetals K.K., Tokyo (Japan)

    2000-09-15

    TiC-TiO{sub 2} composite powders were prepared by in-flight oxidation of titanium carbide powder in RF induction thermal plasmas. Original titanium carbide powder of 20 - 38 {mu}m in particle size was axially injected into the center of argon-oxygen plasma. The powders were partially spheroidized and evaporated through the plasma treatment. X-ray diffraction of plasma-treated powders showed the formation of titanium dioxides, both rutile and anatase phases. The phase content of the plasma-prepared powders strongly depended on the plasma conditions, such as the plasma generating pressure and the oxygen flow rate in plasma generating gas. Especially, the increase of oxygen flow rate in plasma gas gave rise to the increase of heat transfer from plasma to powder particles, exothermic heat of oxidation reaction and cooling rate of plasma, giving the increase of spheroidization ratio, formation ratio of titanium dioxides, and content of anatase phases. (author)

  7. Analysis of the expanding thermal argon-oxygen plasma gas phase

    NARCIS (Netherlands)

    Hest, van M.F.A.M.; Haartsen, J.R.; Weert, van M.H.M.; Schram, D.C.; Sanden, van de M.C.M.

    2003-01-01

    An expanding thermal argon plasma into which oxygen is injected has been analyzed by means of Langmuir and Pitot probe measurements. Information is obtained on the ion d. profile and the flow pattern in the downstream plasma. A combination of Langmuir and Pitot probe measurements provide information

  8. Ion energy loss at maximum stopping power in a laser-generated plasma

    International Nuclear Information System (INIS)

    Cayzac, W.

    2013-01-01

    In the frame of this thesis, a new experimental setup for the measurement of the energy loss of carbon ions at maximum stopping power in a hot laser-generated plasma has been developed and successfully tested. In this parameter range where the projectile velocity is of the same order of magnitude as the thermal velocity of the plasma free electrons, large uncertainties of up to 50% are present in the stopping-power description. To date, no experimental data are available to perform a theory benchmarking. Testing the different stopping theories is yet essential for inertial confinement fusion and in particular for the understanding of the alpha-particle heating of the thermonuclear fuel. Here, for the first time, precise measurements were carried out in a reproducible and entirely characterized beam-plasma configuration. It involved a nearly fully-stripped ion beam probing a homogeneous fully-ionized plasma. This plasma was generated by irradiating a thin carbon foil with two high-energy laser beams and features a maximum electron temperature of 200 eV. The plasma conditions were simulated with a two-dimensional radiative hydrodynamic code, while the ion-beam charge-state distribution was predicted by means of a Monte-Carlo code describing the charge-exchange processes of projectile ions in plasma. To probe at maximum stopping power, high-frequency pulsed ion bunches were decelerated to an energy of 0.5 MeV per nucleon. The ion energy loss was determined by a time-of-flight measurement using a specifically developed chemical-vapor-deposition diamond detector that was screened against any plasma radiation. A first experimental campaign was carried out using this newly developed platform, in which a precision better than 200 keV on the energy loss was reached. This allowed, via the knowledge of the plasma and of the beam parameters, to reliably test several stopping theories, either based on perturbation theory or on a nonlinear T-Matrix formalism. A preliminary

  9. Generation conditions of CW Diode Laser Sustained Plasma

    Science.gov (United States)

    Nishimoto, Koji; Matsui, Makoto; Ono, Takahiro

    2016-09-01

    Laser sustained plasma was generated using 1 kW class continuous wave diode laser. The laser beam was focused on the seed plasma generated by arc discharge in 1 MPa xenon lamp. The diode laser has advantages of high energy conversion efficiency of 80%, ease of maintenance, compact size and availability of conventional quartz based optics. Therefore, it has a prospect of further development compared with conventional CO2 laser. In this study, variation of the plasma shape caused by laser power is observed and also temperature distribution in the direction of plasma radius is measured by optical emission spectroscopy.

  10. Generation of poloidal magnetic field in a hot collisional plasma by inverse Faraday effect

    International Nuclear Information System (INIS)

    Srivastava, M.K.; Lawande, S.V.; Dutta, D.; Sarkar, S.; Khan, M.; Chakraborty, B.

    1996-01-01

    Generation of poloidal magnetic field in a hot and collisional plasma by an inverse Faraday effect is discussed. This field can either be induced by a circularly polarized laser beam (CPLB) or a plane-polarized laser beam (PPLB). For the CPLB, an average field left-angle Re x right-angle ∼I 0 λ∼11.6 MG could be produced in a DT plasma for a high intensity (I 0 =10 22 W/m 2 ) and shorter wavelength (λ=0.35 μm) laser. This field is essentially induced by the field inhomogeneity effect and dominates over that induced by the plasma inhomogeneity effect (left-angle Re x right-angle ∼I 2/3 0 λ 7/3 ∼2.42 MG). The collisional and thermal contribution to left-angle Re x right-angle is just negligible for the CPLB. However, in the case of PPLB the poloidal field is generated only for a hot and collisional plasma and can be quite large for a longer wavelength laser (e.g., CO 2 laser, λ=10.6 μm). The collisional effect induces a field left-angle Re x right-angle ∼0.08 kG, which dominates near the turning point and is independent of the laser parameters. However, in the outer cronal region the thermal pressure effect dominates (e.g., left-angle Re x right-angle ∼I 5/3 0 λ 4/3 ∼3.0 MG). Further, left-angle Re x right-angle for the p-polarized beam is, in general, relatively smaller than that for the s-polarized beam. Practical implications of these results and their limitations are discussed. copyright 1996 American Institute of Physics

  11. Revisiting the thermal effect on shock wave propagation in weakly ionized plasmas

    International Nuclear Information System (INIS)

    Zhou, Qianhong; Dong, Zhiwei; Yang, Wei

    2016-01-01

    Many researchers have investigated shock propagation in weakly ionized plasmas and observed the following anomalous effects: shock acceleration, shock recovery, shock weakening, shock spreading, and splitting. It was generally accepted that the thermal effect can explain most of the experimental results. However, little attention was paid to the shock recovery. In this paper, the shock wave propagation in weakly ionized plasmas is studied by fluid simulation. It is found that the shock acceleration, weakening, and splitting appear after it enters the plasma (thermal) region. The shock splits into two parts right after it leaves the thermal region. The distance between the splitted shocks keeps decreasing until they recover to one. This paper can explain a whole set of features of the shock wave propagation in weakly ionized plasmas. It is also found that both the shock curvature and the splitting present the same photoacoustic deflection (PAD) signals, so they cannot be distinguished by the PAD experiments.

  12. Growth and male reproduction improvement of non-thermal dielectric barrier discharge plasma treatment on chickens

    Science.gov (United States)

    Jiao Zhang, Jiao; Luong Huynh, Do; Chandimali, Nisansala; Kang, Tae Yoon; Kim, Nameun; Mok, Young Sun; Kwon, Taeho; Jeong, Dong Kee

    2018-05-01

    This study investigated whether plasma treatment of fertilized eggs before hatching could affect the growth and reproduction of chickens. Three point five-day-incubated fertilized eggs exposed to non-thermal dielectric barrier discharge plasma at 2.81 W of power for 2 min resulted in the highest growth in chickens. Plasma growth-promoting effect was regulated by the reactive oxygen species homeostasis and the improvement of energy metabolism via increasing serum hormones and adenosine triphosphate levels which were resulted from the regulation of genes involved in antioxidant defense, hormone biosynthesis and energetic metabolism. Interestingly, plasma-treated male chickens conspicuously grew faster than females. Further, aspects of male reproductive system (testosterone level and sperm quality) were improved by the plasma treatment but female reproduction (estradiol and progesterone levels, egg-laying rate and egg weight) had no significant changes. Unfortunately, offspring whose parents were the optimal plasma-treated chickens did not show any difference on growth characteristics and failed to inherit excellent growth features from their parents. Our results suggest a new method to improve the growth rate and male reproductive capacity in poultry but it is only effective in the plasma direct-treated generation.

  13. Electric discharge plasmas influence attachment of cultured CHO k1 cells

    NARCIS (Netherlands)

    Kieft, I.E.; Broers, J.L.V.; Caubet-Hilloutou, V.; Slaaf, D.W.; Ramaekers, F.C.S.; Stoffels - Adamowicz, E.

    2004-01-01

    Non-thermal plasmas can be generated by electric discharges in gases. These plasmas are reactive media, capable of superficial treatment of various materials. A novel non-thermal atmospheric plasma source (plasma needle) has been developed and tested. Plasma appears at the end of a metal pin as a

  14. Pre-Excitation Studies for Rubidium-Plasma Generation

    CERN Document Server

    Aladi, M; Barna, I.F.; Czitrovszky, Aladar; Djotyan, Gagik; Dombi, Peter; Dzsotjan, David; FöLdes, Istvan; Hamar, Gergo; Ignacz, Peter; Kedves, Miklos; Kerekes, Attila; Levai, Peter; Marton, Istvan; Nagy, Attila; Oszetzky, Daniel; Pocsai, Mihaly; Racz, Peter; Raczkevi, Bela; Szigeti, Janos; Sörlei, Zsuzsa; Szipöcs, Robert; Varga, Dezso; Varga-Umbrich, Karoly; Varro, Sandor; Vamos, Lenard; Vesztergombi, György

    2014-01-01

    The key element in the Proton-Driven-Plasma-Wake-Field-Accelerator (AWAKE) project is the generation of highly uniform plasma from Rubidium vapor. The standard way to achieve full ionization is to use high power laser which can assure the over-barrier-ionization (OBI) along the 10 meters long active region. The Wigner-team in Budapest is investigating an alternative way of uniform plasma generation. The proposed Resonance Enhanced Multi Photon Ionization (REMPI) scheme probably can be realized by much less laser power. In the following the resonant pre-excitations of the Rb atoms are investigated, theoretically and the status report about the preparatory work on the experiment are presented.

  15. Self-generated magnetic fields and energy transport by ultra-intense laser-plasma interaction

    International Nuclear Information System (INIS)

    Abudurexiti, A.; Tuniyazi, P.; Wang Qian

    2011-01-01

    The electromagnetic instability (Weibel instability) and its mechanism in ultra-intense laser-plasma interactions are studied by using three-dimensional particle-in-cell simulations. The transport of energy in electron thermal conduction is analyzed by the Spitzer-Harm theory, and the election's vertical pyrogenation phenomenon that resulted from anisotropic heating of laser is observed. The results indicate that the strong magnetic field excited by Weibel instability makes the electron beam deposit its energy within a very short distance, and it restrains the electron thermal flux formed when the laser ponderomotive force bursts through the electron. With the increase of the self-generated magnetic field, the electron will be seized by the wave of magnetic field, and the transport of heat will be restricted. (authors)

  16. Improvement of Polytetrafluoroethylene Surface Energy by Repetitive Pulse Non-Thermal Plasma Treatment in Atmospheric Air

    International Nuclear Information System (INIS)

    Yang Guoqing; Zhang Guanjun; Zhang Wenyuan

    2011-01-01

    Improvement of polytetrafluoroethylene surface energy by non-thermal plasma treatment is presented, using a nanosecond-positive-edge repetitive pulsed dielectric barrier discharge generator in atmospheric air. The electrical parameters including discharging power, peak and density of micro-discharge current were calculated, and the electron energy was estimated. Surface treatment experiments of polytetrafluoroethylene films were conducted for both different applied voltages and different treating durations. Results show that the surface energy of polytetrafluoroethylene film could be improved to 40 mJ/m 2 or more by plasma treatment. Surface roughness measurement and surface X-ray photoelectron spectroscopy analysis indicate that there are chemical etching and implantation of polar oxygen groups in the sample surface treating process, resulting in the improvement of the sample surface energy. Compared with an AC source of 50 Hz, the dielectric barrier discharges generated by a repetitive pulsed source could provide higher peak power, lower mean power, larger micro-discharge current density and higher electron energy. Therefore, with the same applied peak voltage and treating duration, the improvement of polytetrafluoroethylene surface energy using repetitive pulsed plasma is more effective, and the plasma treatment process based on repetitive pulsed dielectric barrier discharges in air is thus feasible and applicable.

  17. Thermal equilibrium of pure electron plasmas across a central region of magnetic surfaces

    Science.gov (United States)

    Hahn, Michael; Pedersen, Thomas Sunn

    2009-06-01

    Measurements of the equilibria of plasmas created by emission from a biased filament located off the magnetic axis in the Columbia Non-neutral Torus (CNT) [T. S. Pedersen, J. P. Kremer, R. G. Lefrancois et al., Fusion Sci. Technol. 50, 372 (2006)] show that such plasmas have equilibrium properties consistent with the inner surfaces being in a state of cross-surface thermal equilibrium. Numerical solutions to the equilibrium equation were used to fit the experimental data and demonstrate consistency with cross-surface thermal equilibrium. Previous experiments in CNT showed that constant temperatures across magnetic surfaces are characteristic of CNT plasmas, implying thermal confinement times much less than particle confinement times. These results show that when emitting off axis there is a volume of inner surfaces where diffusion into that region is balanced by outward transport, producing a Boltzmann distribution of electrons. When combined with the low thermal energy confinement time this is a cross-surface thermal equilibrium.

  18. Thermal equilibrium of pure electron plasmas across a central region of magnetic surfaces

    International Nuclear Information System (INIS)

    Hahn, Michael; Pedersen, Thomas Sunn

    2009-01-01

    Measurements of the equilibria of plasmas created by emission from a biased filament located off the magnetic axis in the Columbia Non-neutral Torus (CNT) [T. S. Pedersen, J. P. Kremer, R. G. Lefrancois et al., Fusion Sci. Technol. 50, 372 (2006)] show that such plasmas have equilibrium properties consistent with the inner surfaces being in a state of cross-surface thermal equilibrium. Numerical solutions to the equilibrium equation were used to fit the experimental data and demonstrate consistency with cross-surface thermal equilibrium. Previous experiments in CNT showed that constant temperatures across magnetic surfaces are characteristic of CNT plasmas, implying thermal confinement times much less than particle confinement times. These results show that when emitting off axis there is a volume of inner surfaces where diffusion into that region is balanced by outward transport, producing a Boltzmann distribution of electrons. When combined with the low thermal energy confinement time this is a cross-surface thermal equilibrium.

  19. Thermal conductivity reduction of tungsten plasma facing material due to helium plasma irradiation in PISCES using the improved 3-omega method

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Shuang [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Simmonds, Michael [Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States); Qin, Wenjing; Ren, Feng [School of Physics and Technology, Wuhan University, Wuhan, Hubei 430072 (China); Tynan, George R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States); Doerner, Russell P. [Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States); Chen, Renkun, E-mail: rkchen@ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States)

    2017-04-01

    The near-surface region of plasma facing material (PFM) plays an important role in thermal management of fusion reactors. In this work, we measured thermal conductivity of tungsten (W) surface layers damaged by He plasma in PISCES at UCSD. We studied the damage effect on both bulk, and thin film, W. We observed that the surface morphology of both bulk and thin film was altered after exposure to He plasma with the fluence of 1 × 10{sup 26} m{sup −2} (bulk) and 2 × 10{sup 24} m{sup −2} (thin film). Transmission electron microscopy (TEM) analysis reveals that the depth of the irradiation damaged layer was approximately 20 nm on the bulk W exposed to He plasma at 773 K for 2000 s. In order to measure the thermal conductivity of this exceedingly thin damaged layer in the bulk W, we adopted the well-established ‘3-omega’ method and employed novel nanofabrication techniques to improve the measurement sensitivity. For the damaged W thin film sample, we measured the reduction in electrical conductivity and used the Wiedemann-Franz (W-F) law to extract the thermal conductivity. Results from both measurements show that thermal conductivity in the damaged layers was reduced by at least ∼80% compared to that of undamaged W. This large reduction in thermal conductivity can be attributed to the scattering of electrons, the dominant heat carriers in W, caused by defects introduced by He plasma irradiation.

  20. A large volume uniform plasma generator for the experiments of electromagnetic wave propagation in plasma

    International Nuclear Information System (INIS)

    Yang Min; Li Xiaoping; Xie Kai; Liu Donglin; Liu Yanming

    2013-01-01

    A large volume uniform plasma generator is proposed for the experiments of electromagnetic (EM) wave propagation in plasma, to reproduce a “black out” phenomenon with long duration in an environment of the ordinary laboratory. The plasma generator achieves a controllable approximate uniform plasma in volume of 260 mm× 260 mm× 180 mm without the magnetic confinement. The plasma is produced by the glow discharge, and the special discharge structure is built to bring a steady approximate uniform plasma environment in the electromagnetic wave propagation path without any other barriers. In addition, the electron density and luminosity distributions of plasma under different discharge conditions were diagnosed and experimentally investigated. Both the electron density and the plasma uniformity are directly proportional to the input power and in roughly reverse proportion to the gas pressure in the chamber. Furthermore, the experiments of electromagnetic wave propagation in plasma are conducted in this plasma generator. Blackout phenomena at GPS signal are observed under this system and the measured attenuation curve is of reasonable agreement with the theoretical one, which suggests the effectiveness of the proposed method.

  1. Water plasma generation under atmospheric pressure for HFC destruction

    International Nuclear Information System (INIS)

    Watanabe, Takayuki; Tsuru, Taira

    2008-01-01

    The purpose of this paper is to investigate the decomposition process of hydrofluoroethylene (HFC-134a) by water plasmas. The water plasma was generated by DC arc discharge with a cathode of hafnium embedded into a copper rod and a nozzle-type copper anode. The advantage of the water plasma torch is the generation of 100%-water plasma by DC discharge. The distinctive steam generation leads to the portable light-weight plasma generation system that does not require the gas supply unit, as well as the high energy efficiency owing to the nonnecessity of the additional water-cooling. HFC-134a was injected into the water plasma jet to decompose it in the reaction tube. Neutralization vessel was combined to the reaction tube to absorb F 2 and HF generated from the HFC-134a decomposition. The decomposition was performed with changing the feed rate of HFC-134a up to 185 mmol/min. The decomposition efficiency of 99.9% can be obtained up to 0.43 mmol/kJ of the ratio of HFC-134a feed rate to the arc power, hence the maximum feed rate was estimated to be 160 g/h at 1 kW of the arc power

  2. Foil-less plasma-filled diode for HPM generator

    International Nuclear Information System (INIS)

    Eltchaninov, A A; Kovalchuk, B M; Kurkan, I K; Zherlitsyn, A A

    2014-01-01

    Plasma-filled diode regarded as perspective source of electron beam feeding HPM generator of GW power level, comparing to conventional explosive emission vacuum diode. Electron beam generation occurs in plasma double layer, where plasma boundary plays as an anode. It allows cancelling the usage of anode foils or grids in HPM generators with the virtual cathode, which could limit its life time to few shots. The presence of ions in the e-beam drift space could raise the limiting current for a drift space, but it could affect to microwave generation also. Sectioned plasma-filled diode with beam current of about 100 kA, electron beam energy of about 0.5 MV and beam current density of 1-10 kA/cm 2 was realized. Cylindrical transport channel with the diameter of 200 mm and the length of about 30 cm was attached to the diode. Beam current measurements in a drift space were performed. Computer simulations of electron beam transport with the presence of ions were carried out with the 2.5D axisymmetric version of PiC-code KARAT. Obtained results would help optimizing electrodynamic system of HPM generator subjected to the presence of ions

  3. Modelling of new generation plasma optical devices

    Directory of Open Access Journals (Sweden)

    Litovko Irina V.

    2016-06-01

    Full Text Available The paper presents new generation plasma optical devices based on the electrostatic plasma lens configuration that opens a novel attractive possibility for effective high-tech practical applications. Original approaches to use of plasma accelerators with closed electron drift and open walls for the creation of a cost-effective low-maintenance plasma lens with positive space charge and possible application for low-cost, low-energy rocket engine are described. The preliminary experimental, theoretical and simulation results are presented. It is noted that the presented plasma devices are attractive for many different applications in the state-of-the-art vacuum-plasma processing.

  4. Simulations of planar non-thermal plasma assisted ignition at atmospheric pressure

    KAUST Repository

    Casey, Tiernan A.; Han, Jie; Belhi, Memdouh; Arias, Paul G.; Bisetti, Fabrizio; Im, Hong G.; Chen, Jyh Yuan

    2016-01-01

    neutrals and ions to the non-thermal electrons. A two-temperature plasma mechanism describing gas phase combustion, excitation of neutral species, and high-energy electron kinetics is employed to account for non-thermal effects. Charged species transported

  5. Non-thermal Plasma Exposure Rapidly Attenuates Bacterial AHL-Dependent Quorum Sensing and Virulence

    Science.gov (United States)

    Flynn, Padrig B.; Busetti, Alessandro; Wielogorska, Ewa; Chevallier, Olivier P.; Elliott, Christopher T.; Laverty, Garry; Gorman, Sean P.; Graham, William G.; Gilmore, Brendan F.

    2016-01-01

    The antimicrobial activity of atmospheric pressure non-thermal plasma has been exhaustively characterised, however elucidation of the interactions between biomolecules produced and utilised by bacteria and short plasma exposures are required for optimisation and clinical translation of cold plasma technology. This study characterizes the effects of non-thermal plasma exposure on acyl homoserine lactone (AHL)-dependent quorum sensing (QS). Plasma exposure of AHLs reduced the ability of such molecules to elicit a QS response in bacterial reporter strains in a dose-dependent manner. Short exposures (30–60 s) produce of a series of secondary compounds capable of eliciting a QS response, followed by the complete loss of AHL-dependent signalling following longer exposures. UPLC-MS analysis confirmed the time-dependent degradation of AHL molecules and their conversion into a series of by-products. FT-IR analysis of plasma-exposed AHLs highlighted the appearance of an OH group. In vivo assessment of the exposure of AHLs to plasma was examined using a standard in vivo model. Lettuce leaves injected with the rhlI/lasI mutant PAO-MW1 alongside plasma treated N-butyryl-homoserine lactone and n-(3-oxo-dodecanoyl)-homoserine lactone, exhibited marked attenuation of virulence. This study highlights the capacity of atmospheric pressure non-thermal plasma to modify and degrade AHL autoinducers thereby attenuating QS-dependent virulence in P. aeruginosa. PMID:27242335

  6. Preliminary degradation process study of infectious biological waste in a 5 k W thermal plasma equipment.; Estudio Preliminar de Proceso de degradacion de residuos biologico-infecciosos en un equipo de plasma termico de 5 kW

    Energy Technology Data Exchange (ETDEWEB)

    Xochihua S M, M C

    1998-12-31

    This work is a preliminary study of infectious biological waste degradation process by thermal plasma and was made in Thermal Plasma Applications Laboratory of Environmental Studies Department of the National Institute of Nuclear Research (ININ). Infectious biological waste degradation process is realized by using samples such polyethylene, cotton, glass, etc., but the present study scope is to analyze polyethylene degradation process with mass and energy balances involved. Degradation method is realized as follow: a polyethylene sample is put in an appropriated crucible localized inside a pyrolysis reactor chamber, the plasma jet is projected to the sample, by the pyrolysis phenomena the sample is degraded into its constitutive particles: carbon and hydrogen. Air was utilized as a recombination gas in order to obtain the higher percent of CO{sub 2} if amount of O{sub 2} is greater in the recombination gas, the CO generation is reduced. The effluent gases of exhaust pyrolysis reactor through are passed through a heat exchanger to get cooled gases, the temperature water used is 15 Centigrade degrees. Finally the gases was tried into absorption tower with water as an absorbent fluid. Thermal plasma degradation process is a very promising technology, but is necessary to develop engineering process area to avail all advantages of thermal plasma. (Author).

  7. Non-Thermal Sanitation By Atmospheric Pressure Plasma, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop a non-thermal technology based on atmospheric-pressure (AP) cold plasma to sanitize foods, food packaging materials, and other hardware...

  8. Investigations of a thermal plasma jet structure by generalized correlation dimension

    Czech Academy of Sciences Publication Activity Database

    Gruber, Jan; Hlína, Jan; Šonský, Jiří

    2013-01-01

    Roč. 46, č. 1 (2013), s. 1-8 ISSN 0022-3727 Institutional research plan: CEZ:AV0Z20570509 Keywords : correlation dimension * turbulence * thermal plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.521, year: 2013

  9. Comparative analysis of turbulent effects on thermal plasma characteristics inside the plasma torches with rod- and well-type cathodes

    International Nuclear Information System (INIS)

    Hur, Min; Hong, Sang Hee

    2002-01-01

    The thermal plasma characteristics inside the two non-transferred plasma torches with rod-type cathode (RTC) and well-type cathode (WTC) are analysed in conjunction with turbulent effects on them in the atmospheric-pressure conditions. A control volume method and a modified semi-implicit pressure linked equations revised algorithm are used for solving the governing equations, i.e. conservation equations of mass, momentum, and energy together with a current continuity equation for arc discharge. A cold flow analysis is introduced to find the cathode spot position in the WTC torch, and both the laminar and turbulent models are employed to gain a physical insight into the turbulent effects on the thermal plasma characteristics produced inside the two torches. The numerical analysis for an RTC torch shows that slightly different values of plasma temperature and velocity between the laminar and turbulent calculations occur and the radial temperature profiles are constricted at the axis with increasing the gas flow rate, and that the large turbulent viscosities appear mostly near the anode wall. These calculated results indicate that the turbulent effects on the thermal plasma characteristics are very weak in the whole discharge region inside the RTC torch. On the other hand, the calculated results of the two numerical simulations for a WTC torch present that the significantly different values of plasma characteristics between the two models appear in the whole torch region and the plasma temperatures decrease with increasing the gas flow rate because the relatively strong turbulent effects are prevailing in the entire interior region of the WTC torch. From the comparisons of plasma net powers calculated and measured in this work, the turbulent modelling turns out to provide the more accurately calculated results close to the measured ones compared with the laminar one, especially for the torch with WTC. This is because the turbulent effects are considerably strong in

  10. Development of non-thermal plasma jet and its potential application for color degradation of organic pollutant in wastewater treatment

    Science.gov (United States)

    Pirdo Kasih, Tota; Kharisma, Angel; Perdana, Muhammad Kevin; Murphiyanto, Richard Dimas Julian

    2017-12-01

    This paper presents the development of non-thermal plasma-based AOPs for color degradation in wastewater treatment. The plasma itself was generated by an in-house high voltage power supply (HVPS). Instead of gas-phase plasma system, we applied plasma jet system underwater during wastewater treatment without additional any chemicals (chemical-free processing). The method is thought to maximize the energy transfer and increase the efficient interaction between plasma and solution during the process. Our plasma jet system could proceed either by using helium (He), argon (Ar) and air as the medium in an open air atmosphere. Exploring the developed plasma to be applied in organic wastewater treatment, we demonstrated that the plasma jet could be generated underwater and yields in color degradation of methylene blue (MB) wastewater model. When using Ar gas as a medium, the color degradation of MB could be achieved within 90 minutes. Whereas, by using Ar with an admixing of oxygen (O2) gas, the similar result could be accomplished within 60 minutes. Additional O2 gas in the latter might produce more hydroxyl radicals and oxygen-based species which speed up the oxidative reaction with organic pollutants, and hence accelerate the process of color degradation.

  11. Wakefield generation in magnetized plasmas

    International Nuclear Information System (INIS)

    Holkundkar, Amol; Brodin, Gert; Marklund, Mattias

    2011-01-01

    We consider wakefield generation in plasmas by electromagnetic pulses propagating perpendicular to a strong magnetic field, in the regime where the electron cyclotron frequency is equal to or larger than the plasma frequency. Particle-in-cell simulations reveal that for moderate magnetic field strengths previous results are reproduced, and the wakefield wave number spectrum has a clear peak at the inverse skin depth. However, when the cyclotron frequency is significantly larger than the plasma frequency, the wakefield spectrum becomes broadband, and simultaneously the loss rate of the driving pulse is much enhanced. A set of equations for the scalar and vector potentials reproducing these results are derived, using only the assumption of a weakly nonlinear interaction.

  12. Thermo-structural modelling of a plasma discharge tube for electric propulsion

    International Nuclear Information System (INIS)

    Faoite, D. de; Browne, D.J.; Del Valle Gamboa, J.I.; Stanton, K.T.

    2016-01-01

    Highlights: • Thermo-structural analyses were performed for an electric propulsion space thruster. • Thermal stresses arise primarily from mismatches in thermal expansion coefficients. • Aluminium nitride is a suitable material for a plasma containment tube. • A design is presented allowing a thruster to operate at a power of at least 250 kW. - Abstract: Potential thermal management strategies for the plasma generation section of a VASIMR"® high-power electric propulsion space thruster are assessed. The plasma is generated in a discharge tube using helicon waves. The plasma generation process causes a significant thermal load on the plasma discharge tube and on neighbouring components, caused by cross-field particle diffusion and UV radiation. Four potential cooling system design strategies are assessed to deal with this thermal load. Four polycrystalline ceramics are evaluated for use as the plasma discharge tube material: alumina, aluminium nitride, beryllia, and silicon nitride. A finite element analysis (FEA) method was used to model the steady-state temperature and stress fields resulting from the plasma heat flux. Of the four materials assessed, aluminium nitride would result in the lowest plasma discharge tube temperatures and stresses. It was found that a design consisting of a monolithic ceramic plasma containment tube fabricated from aluminium nitride would be capable of operating up to a power level of at least 250 kW.

  13. Atmospheric-pressure plasma technology

    International Nuclear Information System (INIS)

    Kogelschatz, U

    2004-01-01

    Major industrial plasma processes operating close to atmospheric pressure are discussed. Applications of thermal plasmas include electric arc furnaces and plasma torches for generation of powders, for spraying refractory materials, for cutting and welding and for destruction of hazardous waste. Other applications include miniature circuit breakers and electrical discharge machining. Non-equilibrium cold plasmas at atmospheric pressure are obtained in corona discharges used in electrostatic precipitators and in dielectric-barrier discharges used for generation of ozone, for pollution control and for surface treatment. More recent applications include UV excimer lamps, mercury-free fluorescent lamps and flat plasma displays

  14. High-order harmonics generation from overdense plasmas

    International Nuclear Information System (INIS)

    Quere, F.; Thaury, C.; Monot, P.; Martin, Ph.; Geindre, J.P.; Audebert, P.; Marjoribanks, R.

    2006-01-01

    Complete test of publication follows. When an intense laser beam reflects on an overdense plasma generated on a solid target, high-order harmonics of the incident laser frequency are observed in the reflected beam. This process provides a way to produce XUV femtosecond and attosecond pulses in the μJ range from ultrafast ultraintense lasers. Studying the mechanisms responsible for this harmonic emission is also of strong fundamental interest: just as HHG in gases has been instrumental in providing a comprehensive understanding of basic intense laser-atom interactions, HHG from solid-density plasmas is likely to become a unique tool to investigate many key features of laser-plasma interactions at high intensities. We will present both experimental and theoretical evidence that two mechanisms contribute to this harmonic emission: - Coherent Wake Emission: in this process, harmonics are emitted by plasma oscillations in te overdense plasma, triggered in the wake of jets of Brunel electrons generated by the laser field. - The relativistic oscillating mirror: in this process, the intense laser field drives a relativistic oscillation of the plasma surface, which in turn gives rise to a periodic phase modulation of the reflected beam, and hence to the generation of harmonics of the incident frequency. Left graph: experimental harmonic spectrum from a polypropylene target, obtained with 60 fs laser pulses at 10 19 W/cm 2 , with a very high temporal contrast (10 10 ). The plasma frequency of this target corresponds to harmonics 15-16, thus excluding the CWE mechanism for the generation of harmonics of higher orders. Images on the right: harmonic spectra from orders 13 et 18, for different distances z between the target and the best focus. At the highest intensity (z=0), harmonics emitted by the ROM mechanism are observed above the 15th order. These harmonics have a much smaller spectral width then those due to CWE (below the 15th order). These ROM harmonics vanish as soon

  15. Optimization of High Porosity Thermal Barrier Coatings Generated with a Porosity Former

    Science.gov (United States)

    Medřický, Jan; Curry, Nicholas; Pala, Zdenek; Vilemova, Monika; Chraska, Tomas; Johansson, Jimmy; Markocsan, Nicolaie

    2015-04-01

    Yttria-stabilized zirconia thermal barrier coatings are extensively used in turbine industry; however, increasing performance requirements have begun to make conventional air plasma sprayed coatings insufficient for future needs. Since the thermal conductivity of bulk material cannot be lowered easily; the design of highly porous coatings may be the most efficient way to achieve coatings with low thermal conductivity. Thus the approach of fabrication of coatings with a high porosity level based on plasma spraying of ceramic particles of dysprosia-stabilized zirconia mixed with polymer particles, has been tested. Both polymer and ceramic particles melt in plasma and after impact onto a substrate they form a coating. When the coating is subjected to heat treatment, polymer burns out and a complex structure of pores and cracks is formed. In order to obtain desired porosity level and microstructural features in coatings; a design of experiments, based on changes in spray distance, powder feeding rate, and plasma-forming atmosphere, was performed. Acquired coatings were evaluated for thermal conductivity and thermo-cyclic fatigue, and their morphology was assessed using scanning electron microscopy. It was shown that porosity level can be controlled by appropriate changes in spraying parameters.

  16. Entropy generation of viscous dissipative flow in thermal non-equilibrium porous media with thermal asymmetries

    International Nuclear Information System (INIS)

    Chee, Yi Shen; Ting, Tiew Wei; Hung, Yew Mun

    2015-01-01

    The effect of thermal asymmetrical boundaries on entropy generation of viscous dissipative flow of forced convection in thermal non-equilibrium porous media is analytically studied. The two-dimensional temperature, Nusselt number and entropy generation contours are analysed comprehensively to provide insights into the underlying physical significance of the effect on entropy generation. By incorporating the effects of viscous dissipation and thermal non-equilibrium, the first-law and second-law characteristics of porous-medium flow are investigated via various pertinent parameters, i.e. heat flux ratio, effective thermal conductivity ratio, Darcy number, Biot number and averaged fluid velocity. For the case of symmetrical wall heat flux, an optimum condition with a high Nusselt number and a low entropy generation is identified at a Darcy number of 10 −4 , providing an ideal operating condition from the second-law aspect. This type of heat and fluid transport in porous media covers a wide range of engineering applications, involving porous insulation, packed-bed catalytic process in nuclear reactors, filtration transpiration cooling, and modelling of transport phenomena of microchannel heat sinks. - Highlights: • Effects of thermal asymmetries on convection in porous-medium are studied. • Exergetic effectiveness of porous media with thermal asymmetries is investigated. • 2-D temperature, Nusselt number and entropy generation contours are analyzed. • Significance of viscous dissipation in entropy generation is scrutinized. • Significance of thermal non-equilibrium in entropy generation is studied

  17. Time-resolved tomographic measurements of temperatures in a thermal plasma jet

    Czech Academy of Sciences Publication Activity Database

    Hlína, Jan; Šonský, Jiří

    2010-01-01

    Roč. 43, č. 5 (2010), s. 1-9 ISSN 0022-3727 Institutional research plan: CEZ:AV0Z20570509 Keywords : thermal plasma jet * optical diagnostics * temperature distribution Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.105, year: 2010

  18. Non-Thermal Plasma Treatment Diminishes Fungal Viability and Up-Regulates Resistance Genes in a Plant Host

    Science.gov (United States)

    Panngom, Kamonporn; Lee, Sang Hark; Park, Dae Hoon; Sim, Geon Bo; Kim, Yong Hee; Uhm, Han Sup; Park, Gyungsoon; Choi, Eun Ha

    2014-01-01

    Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation) while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar) plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR) genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum) after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance. PMID:24911947

  19. Non-thermal plasma treatment diminishes fungal viability and up-regulates resistance genes in a plant host.

    Directory of Open Access Journals (Sweden)

    Kamonporn Panngom

    Full Text Available Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance.

  20. Thermal plasma treatment of cell-phone waste : preliminary result

    Energy Technology Data Exchange (ETDEWEB)

    Ruj, B. [Central Mechanical Engineering Research Inst., Durgapur (India). Thermal Engineering Group; Chang, J.S.; Li, O.L. [McMaster Univ., Hamilton, ON (Canada). Dept. of Engineering Physics; Pietsch, G. [RWTH Aachen Univ., Aachen (Germany)

    2010-07-01

    The cell phone is an indispensable service facilitator, however, the disposal and recycling of cell phones is a major problem. While the potential life span of a mobile phone, excluding batteries, is over 10 years, most of the users upgrade their phones approximately four times during this period. Cell phone waste is significantly more hazardous than many other municipal wastes as it contains thousands of components made of toxic chemicals and metals like lead, cadmium, chromium, mercury, polyvinyl chlorides (PVC), brominated flame retardants, beryllium, antimony and phthalates. Cell phones also use many expensive rare metals. Since cell phones are made up of plastics, metals, ceramics, and trace other substances, primitive recycling or disposal of cell phone waste to landfills and incinerators creates irreversible environmental damage by polluting water and soil, and contaminating air. In order to minimize releases into the environment and threat to human health, the disposal of cell phones needs to be managed in an environmentally friendly way. This paper discussed a safer method of reducing the generation of syngas and hydrocarbons and metal recovery through the treatment of cell phone wastes by a thermal plasma. The presentation discussed the experiment, with particular reference to sample preparation; experimental set-up; and results four samples with different experimental conditions. It was concluded that the plasma treatment of cell phone waste in reduced condition generates gaseous components such as hydrogen, carbon monoxide, and hydrocarbons which are combustible. Therefore, this system is an energy recovery system that contributes to resource conservation and reduction of climate change gases. 5 refs., 2 tabs., 2 figs.

  1. Chemical durability of slag produced by thermal plasma melting of low-level miscellaneous solid wastes. Effects of slag composition

    International Nuclear Information System (INIS)

    Amakawa, Tadashi; Yasui, Shinji

    2001-01-01

    Low-level radioactive miscellaneous solid wastes are generated from commercial operation of nuclear power plants and will be generated from decommissioning of nuclear power plants in future. Static leaching tests were carried out in deionized water of 10degC on slag obtained by thermal plasma melting of simulating materials of the miscellaneous solids wastes with surrogate elements of radionuclides. It is found that logarithm of normalized elemental mass loss from the slag is proportional to the basicity represented by mole fractions of main structural oxides of the slag, such as SiO 2 , Al 2 O 3 , CaO, FeO and MgO. The range of static leaching rates from the slag is determined based on the above results and the basicity range of the miscellaneous solid wastes. Then we compared the leaching rates form the slag and from high level waste glasses. On these grounds, we concluded that the slag obtained by thermal plasma melting of miscellaneous solid wastes can stabilize radio-nuclides in it by no means inferior to the high level waste glasses. (author)

  2. Plasma effects in attosecond pulse generation from ultra-relativistic laser-plasma interactions

    International Nuclear Information System (INIS)

    Boyd, T.J.M.

    2010-01-01

    Complete text of publication follows. Particle-in-cell simulations were performed to examine the influence of plasma effects on high harmonic spectra from the interaction of ultra-intense p-polarized laser pulses with overdense plasma targets. Furthermore, a theoretical model is proposed to explain the radiation mechanism that leads to attosecond pulse generation in the reflected field. It is shown that plasma harmonic emission affects the spectral characteristics, causing deviations in the harmonic power decay as compared with the so-called universal 8/3-decay. These deviations may occur, in a varying degree, as a consequence of the extent to which the plasma line and its harmonics affect the emission. It is also found a strong correlation of the emitted attosecond pulses with electron density structures within the plasma, responsible to generate intense localised electrostatic fields. A theoretical model based on the excitation of Langmuir waves by the re-entrant Brunel electron beams in the plasma and their electromagnetic interaction with the laser field is proposed to explain the flatter power spectral emission - described by a weaker 5/3 index and observed in numerical simulations - than that of the universal decay.

  3. Spatial Dynamics of Coherent Structures in a Thermal Plasma Jet

    Czech Academy of Sciences Publication Activity Database

    Hlína, Jan; Sekerešová, Zuzana; Šonský, Jiří

    2008-01-01

    Roč. 36, č. 4 (2008), s. 1066-1067 ISSN 0093-3813 R&D Projects: GA ČR GA202/05/0728 Institutional research plan: CEZ:AV0Z20570509 Keywords : charge-coupled-device (CCD) camera * coherent structure * thermal plasma jet * turbulence Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.447, year: 2008

  4. Atmospheric non-thermal argon-oxygen plasma for sunflower seedling growth improvement

    Science.gov (United States)

    Matra, Khanit

    2018-01-01

    Seedling growth enhancement of sunflower seeds by DC atmospheric non-thermal Ar-O2 plasma has been proposed. The plasma reactor was simply designed by the composition of multi-pin electrodes bonded on a solderable printed circuit board (PCB) anode. A stable plasma was exhibited in the non-periodical self-pulsing discharge mode during the seed treatment. The experimental results showed that non-thermal plasma treatment had a significant positive effect on the sunflower seeds. Ar-O2 mixed gas ratio, treatment time and power source voltage are the important parameters affecting growth stimulation of sunflower sprouts. In this research, the sunflower seeds treated with 3:3 liters per minute (LPM) of Ar-O2 plasma at a source voltage of 8 kV for 1 min showed the best results in stimulating the seedling growth. The results in this case showed that the dry weight and average shoot length of the sunflower sprouts were 1.79 and 2.69 times higher and heavier than those of the untreated seeds, respectively.

  5. Plasma flow driven by fusion-generated alpha particles

    International Nuclear Information System (INIS)

    Ikuta, Kazunari.

    1978-05-01

    The confinement of fusion-generated alpha particles will affect the transports of the background plasma particles by the momentum transfer from the energetic alphas. The ions tend to migrate towards the center of plasma (i.e. fuel injection) and electrons towards the plasma periphery. This means the existence of a mechanism which enable to pump out the ashes in the fuel plasma because of the momentum conservation of whole plasma particles. (author)

  6. Investigating the Plasma-Assisted and Thermal Catalytic Dry Methane Reforming for Syngas Production: Process Design, Simulation and Evaluation

    Directory of Open Access Journals (Sweden)

    Evangelos Delikonstantis

    2017-09-01

    Full Text Available The growing surplus of green electricity generated by renewable energy technologies has fueled research towards chemical industry electrification. By adapting power-to-chemical concepts, such as plasma-assisted processes, cheap resources could be converted into fuels and base chemicals. However, the feasibility of those electrified processes at large scale has not been investigated yet. Thus, the current work strives to compare, for first time in the literature, plasma-assisted production of syngas, from CH4 and CO2 (dry methane reforming, with thermal catalytic dry methane reforming. Specifically, both processes are conceptually designed to deliver syngas suitable for methanol synthesis (H2/CO ≥ 2 in mole. The processes are simulated in the Aspen Plus process simulator where different process steps are investigated. Heat integration and equipment cost estimation are performed for the most promising process flow diagrams. Collectively, plasma-assisted dry methane reforming integrated with combined steam/CO2 methane reforming is an effective way to deliver syngas for methanol production. It is more sustainable than combined thermal catalytic dry methane reforming with steam methane reforming, which has also been proposed for syngas production of H2/CO ≥ 2; in the former process, 40% more CO2 is captured, while 38% less H2O is consumed per mol of syngas. Furthermore, the plasma-assisted process is less complex than the thermal catalytic one; it requires higher amount of utilities, but comparable capital investment.

  7. Thermal efficiency of a non-transferred thermal plasma cannon; Eficiencia termica de un canon de plasma termico no-transferido

    Energy Technology Data Exchange (ETDEWEB)

    Mercado, A; Cota, G; Merlo, L; Pacheco, J; Pena, R; Cruz, A [Instituto nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    This work shows a thermal efficiency research ({nu}) for a plasma torch in d.c. which was carried out through the realization of an energy balance around the system under consideration. The plasma torch is manufactured in copper with a tungsten incrustations in cathode. The gas used was argon and the gas fluxes were at the rank of 10 and 40 lt/min to the total pressure of 1.2 bar (1.1 atm). With these conditions it was worked with electric currents at the rank of 40 and 180 A. The data were collected through a data acquisition card which was programmed in Windows environment. (Author)

  8. New generation of plasma-sprayed mullite coatings on silicon carbide

    Science.gov (United States)

    Lee, Kang N.; Miller, Robert A.; Jacobson, Nathan S.

    1995-01-01

    Mullite is promising as a protective coating for silicon-based ceramics in aggressive high-temperature environments. Conventionally plasma-sprayed mullite on SiC tends to crack and debond on thermal cycling. It is shown that this behavior is due to the presence of amorphous mullite in the conventionally sprayed mullite. Heating the SiC substrate during the plasma spraying eliminated the amorphous phase and produced coatings with dramatically improved properties. The new coating exhibits excellent adherence and crack resistance under thermal cycling between room temperature and 1000 to 1400 C. Preliminary tests showed good resistance to Na2CO3-induced hot corrosion.

  9. Thermal plasma treatment of stormwater sediments: comparison between DC non-transferred and partially transferred arc plasma.

    Science.gov (United States)

    Li, O L; Guo, Y; Chang, J S; Saito, N

    2015-01-01

    The disposal of enormous amount of stormwater sediments becomes an emerging worldwide problem. Stormwater sediments are contaminated by heavy metals, phosphorus, trace organic and hydrocarbons, and cannot be disposed without treatment. Thermal plasma decontamination technology offers a high decomposition rate in a wide range of toxic organic compound and immobilization of heavy metal. In this study, we compared the treatment results between two different modes of thermal plasma: (1) a non-transferred direct current (DC) mode and (2) a partial DC-transferred mode. The reductions of total organic carbon (TOC) were, respectively, 25% and 80% for non-transferred and partially transferred plasma, respectively. Most of the toxic organic compounds were converted majorly to CxHy. In the gaseous emission, the accumulated CxHy, CO, NO and H2S were significantly higher in partially transferred mode than in non-transferred mode. The solid analysis demonstrated that the concentrations of Ca and Fe were enriched by 500% and 40%, respectively. New chemical compositions such as KAlSi3O8, Fe3O4, NaCl and CaSO4 were formed after treatment in partially DC-transferred mode. The power inputs were 1 and 10 kW, respectively, for non-transferred DC mode and a partially DC-transferred mode. With a lower energy input, non-transferred plasma treatment can be used for decontamination of sediments with low TOC and metal concentration. Meanwhile, partially transferred thermal plasma with higher energy input is suitable for treating sediments with high TOC percentage and volatile metal concentration. The organic compounds are converted into valuable gaseous products which can be recycled as an energy source.

  10. Non-thermal plasma mills bacteria: scanning electron microscopy observations

    Czech Academy of Sciences Publication Activity Database

    Lunov, Oleg; Churpita, Olexandr; Zablotskyy, Vitaliy A.; Deyneka, I.G.; Meshkovskii, I.K.; Jäger, Aleš; Syková, Eva; Kubinová, Šárka; Dejneka, Alexandr

    2015-01-01

    Roč. 106, č. 5 (2015), "053703-1"-"053703-5" ISSN 0003-6951 R&D Projects: GA MŠk(CZ) LM2011029; GA MŠk(CZ) LM2011026; GA MŠk LO1309 Grant - others:AV ČR(CZ) M100101219; SAFMAT(XE) CZ.2.16/3.1.00/22132 Institutional support: RVO:68378271 ; RVO:68378041 Keywords : non-thermal plasma * plasma medicine * bacteria * cells Subject RIV: BO - Biophysics Impact factor: 3.142, year: 2015

  11. Numerical study of divertor plasma transport with thermal force due to temperature gradient

    International Nuclear Information System (INIS)

    Ohtsu, Shigeki; Tanaka, Satoru; Yamawaki, Michio

    1992-01-01

    A one-dimensional, steady state divertor plasma model is developed in order to study the carbon impurity transport phenomena considering thermal force. The divertor plasma is composed of four regions in terms of momentum transport between hydrogen and carbon impurity: Momentum transferring region, equilibrium region, hydrogen recycling region and carbon recycling region. In the equilibrium region where the friction force is counterbalanced by the thermal force, the localization of carbon impurity occurs. The sufficient condition to avoid the reverse of carbon velocity due to the thermal force is evaluated. (orig.)

  12. Repetitive plasma opening switch for powerful high-voltage pulse generators

    International Nuclear Information System (INIS)

    Dolgachev, G.I.; Zakatov, L.P.; Nitishinskii, M.S.; Ushakov, A.G.

    1998-01-01

    Results are presented of experimental studies of plasma opening switches that serve to sharpen the pulses of inductive microsecond high-voltage pulse generators. It is demonstrated that repetitive plasma opening switches can be used to create super-powerful generators operating in a quasi-continuous regime. An erosion switching mechanism and the problem of magnetic insulation in repetitive switches are considered. Achieving super-high peak power in plasma switches makes it possible to develop new types of high-power generators of electron beams and X radiation. Possible implementations and the efficiency of these generators are discussed

  13. Progress report : Plasma Physics Section

    International Nuclear Information System (INIS)

    Iyyengar, S.K.; Rohatgi, V.K.

    1975-08-01

    The activities of the plasma physics section of the Bhabha Atomic Research Centre, India over the last five years (1970-75) are reported. The R and D programme of the section has been divided into four cells mainly i.e., (i) Thermal plasma (ii) Relativistic Electron Beam (iii) Energetics and (iv) Electron beam technology. The salient features of the development activities carried out in these cells are outlined. In the Thermal plasma group, considerable research work has been done in (a) fundamental plasma studies, (b) industrial plasma technology and (c) open cycle MHD power generation project. The relativistic electron beam group is engaged in improving the technology to realize high power lasers, and pulsed thermonuclear fusion. The energetics programme is oriented to develop high voltage d.c. generators and pulse generators. The electron beam techniques developed here are routinely used for melting refractory and reactive metals. The technical know-how of the welding machines developed has been transfered to industries. Equipment developed by this section, such as, (1) electron beam furnace, (2) plasma cutting torch, (3) impulse magnet charger etc. are listed. (A.K.)

  14. Electron thermal transport in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Konings, J A

    1994-11-30

    The process of fusion of small nuclei thereby releasing energy, as it occurs continuously in the sun, is essential for the existence of mankind. The same process applied in a controlled way on earth would provide a clean and an abundant energy source, and be the long term solution of the energy problem. Nuclear fusion requires an extremely hot (10{sup 8} K) ionized gas, a plasma, that can only be maintained if it is kept insulated from any material wall. In the so called `tokamak` this is achieved by using magnetic fields. The termal insulation, which is essential if one wants to keep the plasma at the high `fusion` temperature, can be predicted using basic plasma therory. A comparison with experiments in tokamaks, however, showed that the electron enery losses are ten to hundred times larger than this theory predicts. This `anomalous transport` of thermal energy implies that, to reach the condition for nuclear fusion, a fusion reactor must have very large dimensions. This may put the economic feasibility of fusion power in jeopardy. Therefore, in a worldwide collaboration, physicists study tokamak plasmas in an attempt to understand and control the energy losses. From a scientific point of view, the mechanisms driving anomalous transport are one of the challenges in fudamental plasma physics. In Nieuwegein, a tokamak experiment (the Rijnhuizen Tokamak Project, RTP) is dedicated to the study of anomalous transport, in an international collaboration with other laboratories. (orig./WL).

  15. Generation of radiation by intense plasma and electromagnetic undulators

    International Nuclear Information System (INIS)

    Joshi, C.

    1989-01-01

    This is a second year progress report which details the work on the generation of radiation by intense plasma and electromagnetic undulators being carried out at UCLA. The status of the experimental work is described and the future directions are outlined. We have completed the first phase of experiments on the plasma wiggler generation and characterization. Suitability of a null-pinch as a plasma source was investigated in great detail. It is found that a w of a few percent can be excited but there are trapped magnetic fields within null-pinch plasma which hinder the injection of the electrons. A new more uniform and field-free plasma source is now being characterized

  16. Generation of radiation by intense plasma and electromagnetic undulators

    International Nuclear Information System (INIS)

    Joshi, C.

    1989-01-01

    This is a second year progress report which details the work on the generation of radiation by intense plasma and electromagnetic undulators being carried out at UCLA. The status of the experimental work is described and the future directions are outlined. We have completed the first phase of experiments on the plasma wiggler generation and characterization. Suitability of a θ-pinch as a plasma source was investigated in great detail. It is found that a w of a few percent can be excited but there are trapped magnetic fields within θ-pinch plasma which hinder the injection of the electrons. A few more uniform and field-free plasma source is now being characterized. 8 refs., 5 figs

  17. Electron beam manipulation, injection and acceleration in plasma wakefield accelerators by optically generated plasma density spikes

    Energy Technology Data Exchange (ETDEWEB)

    Wittig, Georg; Karger, Oliver S.; Knetsch, Alexander [Institute of Experimental Physics, University of Hamburg, 22761 Hamburg (Germany); Xi, Yunfeng; Deng, Aihua; Rosenzweig, James B. [Particle Beam Physics Laboratory, UCLA, Los Angeles, CA 90095 (United States); Bruhwiler, David L. [RadiaSoft LLC, Boulder, CO 80304 (United States); RadiaBeam Technologies LLC (United States); Smith, Jonathan [Tech-X UK Ltd, Daresbury, Cheshire WA4 4FS (United Kingdom); Sheng, Zheng-Ming; Jaroszynski, Dino A.; Manahan, Grace G. [Physics Department, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Hidding, Bernhard [Institute of Experimental Physics, University of Hamburg, 22761 Hamburg (Germany); Physics Department, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2016-09-01

    We discuss considerations regarding a novel and robust scheme for optically triggered electron bunch generation in plasma wakefield accelerators [1]. In this technique, a transversely propagating focused laser pulse ignites a quasi-stationary plasma column before the arrival of the plasma wake. This localized plasma density enhancement or optical “plasma torch” distorts the blowout during the arrival of the electron drive bunch and modifies the electron trajectories, resulting in controlled injection. By changing the gas density, and the laser pulse parameters such as beam waist and intensity, and by moving the focal point of the laser pulse, the shape of the plasma torch, and therefore the generated trailing beam, can be tuned easily. The proposed method is much more flexible and faster in generating gas density transitions when compared to hydrodynamics-based methods, and it accommodates experimentalists needs as it is a purely optical process and straightforward to implement.

  18. Plasma effects on the passive external thermal control coating of Space Station Freedom

    Science.gov (United States)

    Carruth, Ralph, Jr.; Vaughn, Jason A.; Holt, James M.; Werp, Richard; Sudduth, Richard D.

    1992-01-01

    The current baseline chromic acid anodized thermal control coating on 6061-T6 aluminum meteoroid debris (M/D) shields for SSF has been evaluated. The degradation of the solar absorptance, alpha, and the thermal emittance, epsilon, of chromic acid anodized aluminum due to dielectric breakdown in plasma was measured to predict the on-orbit lifetime of the SSF M/D shields. The lifetime of the thermal control coating was based on the surface temperatures achieved with degradation of the thermal control properties, alpha and epsilon. The temperatures of each M/D shield from first element launch (FEL) through FEL+15 years were analyzed. It is shown that the baseline thermal control coating cannot withstand the -140 V potential between the conductive structure of the SSF and the current plasma environment.

  19. Recent progress in the modelling of thermal plasma systems

    International Nuclear Information System (INIS)

    Xi Chen

    2002-01-01

    Plasma flow and heat transfer in thermal plasma systems are often of three-dimensional (3-D) features and cannot be well studied by use of a two-dimensional modelling approach. 3-D modelling studies are recently performed in our group. It is found that appreciable 3-D effects exist within non-transferred DC arc plasma torches even for the case with axisymmetrical external conditions. The key for the successful 3-D modelling of the non-transferred arc plasma torch is that the anode-nozzle wall is included in the computational domain. The predicted results are favorably compared with experimental observation. 3-D modelling of the plasma jets with lateral injection of particulate matter and its carrier gas also reveals distinct 3-D effects with the injection velocity and the distance between the carrier-gas injection-tube tip and the jet edge as critical parameters. The 3-D effects appreciably influence the trajectories and heating histories of particles injected into the plasma jet. (author)

  20. Microwave plasmas generated in bubbles immersed in liquids for hydrocarbons reforming

    International Nuclear Information System (INIS)

    Levko, Dmitry; Sharma, Ashish; Raja, Laxminarayan L

    2016-01-01

    We present a computational modeling study of microwave plasma generated in cluster of atmospheric-pressure argon bubbles immersed in a liquid. We demonstrate that the use of microwaves allows the generation of a dense chemically active non-equilibrium plasma along the gas–liquid interface. Also, microwaves allow generation of overdense plasma in all the bubbles considered in the cluster which is possible because the collisional skin depth of the wave exceeds the bubble dimension. These features of microwave plasma generation in bubbles immersed in liquids are highly desirable for the large-scale liquid hydrocarbon reforming technologies. (letter)

  1. Horizontal steam generator PGV-1000 thermal-hydraulic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ubra, O. [Skoda Company, Prague (Switzerland); Doubek, M. [Czech Technical Univ., Prague (Switzerland)

    1995-12-31

    A computer program for the steady state thermal-hydraulic analysis of horizontal steam generator PGV-1000 is presented. The program provides the capability to analyze steam generator PGV-1000 primary side flow and temperature distribution, primary side pressure drops, heat transfer between the primary and secondary sides and multidimensional heat flux distribution. A special attention is paid to the thermal-hydraulics of the secondary side. The code predicts 3-D distribution of the void fraction at the secondary side, mass redistribution under the submerged perforated sheet and the steam generator level profile. By means of developed computer program a detailed thermal-hydraulic study of the PGV-1000 has been carried out. A wide range of calculations has been performed and a set of important steam generator characteristics has been obtained. Some of them are presented in the paper. (orig.). 5 refs.

  2. Horizontal steam generator PGV-1000 thermal-hydraulic analysis

    International Nuclear Information System (INIS)

    Ubra, O.; Doubek, M.

    1995-01-01

    A computer program for the steady state thermal-hydraulic analysis of horizontal steam generator PGV-1000 is presented. The program provides the capability to analyze steam generator PGV-1000 primary side flow and temperature distribution, primary side pressure drops, heat transfer between the primary and secondary sides and multidimensional heat flux distribution. A special attention is paid to the thermal-hydraulics of the secondary side. The code predicts 3-D distribution of the void fraction at the secondary side, mass redistribution under the submerged perforated sheet and the steam generator level profile. By means of developed computer program a detailed thermal-hydraulic study of the PGV-1000 has been carried out. A wide range of calculations has been performed and a set of important steam generator characteristics has been obtained. Some of them are presented in the paper. (orig.)

  3. Horizontal steam generator PGV-1000 thermal-hydraulic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ubra, O [Skoda Company, Prague (Switzerland); Doubek, M [Czech Technical Univ., Prague (Switzerland)

    1996-12-31

    A computer program for the steady state thermal-hydraulic analysis of horizontal steam generator PGV-1000 is presented. The program provides the capability to analyze steam generator PGV-1000 primary side flow and temperature distribution, primary side pressure drops, heat transfer between the primary and secondary sides and multidimensional heat flux distribution. A special attention is paid to the thermal-hydraulics of the secondary side. The code predicts 3-D distribution of the void fraction at the secondary side, mass redistribution under the submerged perforated sheet and the steam generator level profile. By means of developed computer program a detailed thermal-hydraulic study of the PGV-1000 has been carried out. A wide range of calculations has been performed and a set of important steam generator characteristics has been obtained. Some of them are presented in the paper. (orig.). 5 refs.

  4. Plasma thermal conversion of bio-oil for hydrogen production

    International Nuclear Information System (INIS)

    Guenadou, David; Lorcet, Helene; Peybernes, Jean; Catoire, Laurent; Osmont, Antoine; Gokalp, Iskender

    2012-01-01

    Numerous processes exist or are proposed for the energetic conversion of biomass. The use of thermal plasma is proposed in the frame of the GALACSY project for the conversion of bio-oil to hydrogen and carbon monoxide. For this purpose, an experimental apparatus has been built. The feasibility of this conversion at very high temperature, as encountered in thermal plasma, is examined both experimentally and numerically. This zero dimensional study tends to show that a high temperature (around 2500 K or above) is needed to ensure a high yield of hydrogen (about 50 mol%) and about 95 mol% of CO+H 2 . Predicted CO+H 2 yield and CO/H 2 ratio are consistent with measurements. It is also expected that the formation of particles and tars is hampered. Thermodynamic data of selected bio-oil components are provided in the CHEMKINNASA format. (authors)

  5. Non-thermal Plasma Activates Human Keratinocytes by Stimulation of Antioxidant and Phase II Pathways

    Science.gov (United States)

    Schmidt, Anke; Dietrich, Stephan; Steuer, Anna; Weltmann, Klaus-Dieter; von Woedtke, Thomas; Masur, Kai; Wende, Kristian

    2015-01-01

    Non-thermal atmospheric pressure plasma provides a novel therapeutic opportunity to control redox-based processes, e.g. wound healing, cancer, and inflammatory diseases. By spatial and time-resolved delivery of reactive oxygen and nitrogen species, it allows stimulation or inhibition of cellular processes in biological systems. Our data show that both gene and protein expression is highly affected by non-thermal plasma. Nuclear factor erythroid-related factor 2 (NRF2) and phase II enzyme pathway components were found to act as key controllers orchestrating the cellular response in keratinocytes. Additionally, glutathione metabolism, which is a marker for NRF2-related signaling events, was affected. Among the most robustly increased genes and proteins, heme oxygenase 1, NADPH-quinone oxidoreductase 1, and growth factors were found. The roles of NRF2 targets, investigated by siRNA silencing, revealed that NRF2 acts as an important switch for sensing oxidative stress events. Moreover, the influence of non-thermal plasma on the NRF2 pathway prepares cells against exogenic noxae and increases their resilience against oxidative species. Via paracrine mechanisms, distant cells benefit from cell-cell communication. The finding that non-thermal plasma triggers hormesis-like processes in keratinocytes facilitates the understanding of plasma-tissue interaction and its clinical application. PMID:25589789

  6. Enhanced resonant second harmonic generation in plasma based on density transition

    Directory of Open Access Journals (Sweden)

    Kant Niti

    2015-06-01

    Full Text Available Resonant second harmonic generation of a relativistic self-focusing laser in plasma with density ramp profile has been investigated. A high intense Gaussian laser beam generates resonant second harmonic beam in plasma with density ramp profile. The second harmonic undergoes periodic focusing in the plasma channel created by the fundamental wave. The normalized second harmonic amplitude varies periodically with distance and attains maximum value in the focal region. Enhancement in the second harmonic amplitude on account of relativistic self-focusing of laser based on plasma density transition is seen. Plasma density ramp plays an important role to make self-focusing stronger which leads to enhance the second harmonic generation in plasma.

  7. Application of pulsed power and power modulation to the non-thermal plasma treatment of hazardous gaseous wastes

    International Nuclear Information System (INIS)

    Penetrante, B.M.

    1992-10-01

    Acid rain, global warming, ozone depletion, and smog are preeminent environmental problems facing the world today. Non-thermal plasma techniques offer an innovative approach to the cost-effective solution of these problems. Many potential applications of non-thermal plasmas to air pollution control have already been demonstrated. The use of pulsed power and power modulation is essential to the successful implementation of non-thermal plasma techniques. This paper provides an overview of the most recent developments in non-thermal plasma systems that have been applied to gaseous waste treatment. In the non-thermal plasma approach, the nonequilibrium properties of the plasma are fully exploited. These plasmas are characterized by high electron temperatures, while the gas remains at near ambient temperature and pressure. The energy is directed preferentially to the undesirable components, which are often present in very small concentrations. These techniques utilize the dissociation and ionization of the background gas to produce radicals which, in turn, decompose the toxic compounds. The key to success in the non-thermal plasma approach is to produce a discharge in which the majority of the electrical energy goes into the production of energetic electrons, rather than into gas heating. For example, in a typical application to flue gas cleanup, these electrons produce radicals, such as O and OH, through the dissociation or ionization of molecules such as H 2 O or O 2 . The radicals diffuse through the gas and preferentially oxidize the nitrogen oxides and sulfur oxides to form acids that can then be easily neutralized to form non-toxic, easily-collectible (and commercially salable) compounds. Non-thermal plasmas can be created in essentially two different ways: by electron-beam irradiation, and by electrical discharges

  8. Temporal behaviour of self generated magnetic field and its influence on inhibition of thermal flux in ICF plasma

    International Nuclear Information System (INIS)

    Jha, L.N.

    1989-06-01

    The self generated magnetic field of megagauss order is reported to play a crucial role in ICF target designs because of its strong influence on the transport of energy from the critical density region to the ablation layer. The inhibition of the thermal flux due to such a field, thus, affects the whole of the other phenomenon of ICF. The knowledge of the proper variation of the magnetic field may help in assigning the existing controversial value of flux limit, f. Many papers dealing with the spatial variation of such a field exist and are well documented but the study on the variation of self generated field with time is rare. Here, the spatial variation of the megagauss field generated in the corona of a wire target irradiated by a laser as well as a model to study the temporal nature of the B-field at the peak have been obtained by solving the self inhibited diffusion which is regarded as the most dominant mechanism by which the thermal transport is influenced. The field exists for about ten nanoseconds even after the laser is switched off. The ratio of the two components of the thermal conductivity is also plotted against time and shows the inhibition. So, a track on the B-field variation both in space and time is necessary to keep for at least a few nanoseconds for computation of f. (author). 19 refs, 4 figs

  9. Thermal fluctuations and critical behavior in a magnetized, anisotropic plasma

    International Nuclear Information System (INIS)

    Hazeltine, R. D.; Mahajan, S. M.

    2013-01-01

    Thermal fluctuations in a magnetized, anisotropic plasma are studied by applying standard methods, based on the Einstein rule, to the known thermodynamic potential of the system. It is found in particular that magnetic fluctuations become critical when the anisotropy p ∥ −p ⊥ changes sign. By examining the critical region, additional insight on the equations of state for near-critical anisotropic plasma is obtained

  10. Improvement of thermal conductivity of ceramic matrix composites for 4. generation nuclear reactors

    International Nuclear Information System (INIS)

    Cabrero, J.

    2009-11-01

    This study deals with thermal conductivity improvement of SiCf/SiC ceramic matrix composites materials to be used as cladding material in 4. generation nuclear reactor. The purpose of the study is to develop a composite for which both the temperature and irradiation effect is less pronounced on thermal conductivity of material than for SiC. This material will be used as matrix in CMC with SiC fibers. Some TiC-SiC composites with different SiC volume contents were prepared by spark plasma sintering (SPS). The sintering process enables to fabricate specimens very fast, with a very fine microstructure and without any sintering aids. Neutron irradiation has been simulated using heavy ions, at room temperature and at 500 C. Evolution of the thermal properties of irradiated materials is measured using modulated photothermal IR radiometry experiment and was related to structural evolution as function of dose and temperature. It appears that such approach is reliable to evaluate TiC potentiality as matrix in CMC. Finally, CMC with TiC matrix and SiC fibers were fabricated and both mechanical and thermal properties were measured and compare to SiCf/SiC CMC. (author)

  11. Transport of high fluxes of hydrogen plasma in a linear plasma generator

    NARCIS (Netherlands)

    Vijvers, W.A.J.; Al, R.S.; Lopes Cardozo, N.J.; Goedheer, W.J.; Groot, de B.; Kleyn, A.W.; Meiden, van der H.J.; Peppel, van de R.J.E.; Schram, D.C.; Shumack, A.E.; Westerhout, J.; Rooij, van G.J.; Schmidt, J.; Simek, M.; Pekarek, S.; Prukner, V.

    2007-01-01

    A study was made to quantify the losses during the convective hydrogen plasma transport in the linear plasma generator Pilot-PSI due to volume recombination. A transport efficiency of 35% was achieved at neutral background pressures below ~7 Pa in a magnetic field of 1.2 T. This efficiency decreased

  12. Departures from thermal equilibrium in a dense Z-pinch plasma

    International Nuclear Information System (INIS)

    Neufeld, C.R.

    1979-01-01

    This paper presents on analysis of several features of the emission spectrum obtained from a dense hydrogen Z-pinch plasma. The spectrum is characterized by an extremely broad H/sub β/ line and by the absence of an emission line at the H/sub b/ wavelength. Comparison with theory shows that the spectrum is inconsistent with the assumption of a thermal or collision-dominated plasma. The assumption of a substantial overpopulation of the atomic-hydrogen excited levels, ascribed to a rising degree of plasma ionization, provides a satisfactory description of the observed spectrum. This result illustrates the difficulty of establishing valid equilibrium criteria for transient plasmas, even in the case of plasma densities as high as 10 19 cm -3

  13. Theoretical investigation of thermophysical properties in two-temperature argon-helium thermal plasma

    International Nuclear Information System (INIS)

    Sharma, Rohit; Singh, Kuldip; Singh, Gurpreet

    2011-01-01

    The thermophysical properties of argon-helium thermal plasma have been studied in the temperature range from 5000 to 40 000 K at atmospheric pressure in local thermodynamic equilibrium and non-local thermodynamic equilibrium conditions. Two cases of thermal plasma considered are (i) ground state plasma in which all the atoms and ions are assumed to be in the ground state and (ii) excited state plasma in which atoms and ions are distributed over various possible excited states. The influence of electronic excitation and non-equilibrium parameter θ = T e /T h on thermodynamic properties (composition, degree of ionization, Debye length, enthalpy, and total specific heat) and transport properties (electrical conductivity, electron thermal conductivity, and thermal diffusion ratio) have been studied. Within the framework of Chapman-Enskog method, the higher-order contributions to transport coefficient and their convergence are studied. The influence of different molar compositions of argon-helium plasma mixture on convergence of higher-orders is investigated. Furthermore, the effect of different definitions of Debye length has also been examined for electrical conductivity and it is observed that electrical conductivity with the definition of Debye length (in which only electrons participate in screening) is less than that of the another definition (in which both the electrons and ions participate in screening) and this deviation increases with electron temperature. Finally, the effect of lowering of ionization energy is examined on electron number density, Debye length, and higher-order contribution to electrical conductivity. It is observed that the lowering of the ionization energy affects the electron transport-properties and consequently their higher-order contributions depending upon the value of the non-equilibrium parameter θ.

  14. High order harmonic generation from plasma mirror

    International Nuclear Information System (INIS)

    Thaury, C.

    2008-09-01

    When an intense laser beam is focused on a solid target, its surface is rapidly ionized and forms a dense plasma that reflects the incident field. For laser intensities above few 10 15 W/cm 2 , high order harmonics of the laser frequency, associated in the time domain to a train of atto-second pulses (1 as = 10 18 s), can be generated upon this reflection. Because such a plasma mirror can be used with arbitrarily high laser intensities, this process should eventually lead to the production of very intense pulses in the X-ray domain. In this thesis, we demonstrate that for laser intensities about 10 19 W/cm 2 , two mechanisms can contribute to the generation of high order harmonics: the coherent wake emission and the relativistic emission. These two mechanisms are studied both theoretically and experimentally. In particular, we show that, thanks to very different properties, the harmonics generated by these two processes can be unambiguously distinguished experimentally. We then investigate the phase properties of the harmonic, in the spectral and in the spatial domain. Finally, we illustrate how to exploit the coherence of the generation mechanisms to get information on the dynamics of the plasma electrons. (author)

  15. Powder processing and spheroidizing with thermal inductively coupled plasma

    International Nuclear Information System (INIS)

    Nutsch, G.; Linke, P.; Zakharian, S.; Dzur, B.; Weiss, K.-H.

    2001-01-01

    Processing of advanced powder materials for the spraying industry is one of the most promising applications of the thermal RF inductively coupled plasma. By selecting the feedstock carefully and adjusting the RF plasma parameters, unique materials with high quality can be achieved. Powders injected in the hot plasma core emerge with modified shapes, morphology, crystal structure and chemical composition. Ceramic oxide powders such as Al 2 O 3 , ZrO 2 , SiO 2 are spheroidized with a high spheroidization rate. By using the RF induction plasma spheroidizing process tungsten melt carbide powders are obtained with a high spheroidization rate at high feeding rates by densification of agglomerated powders consisting of di-tungsten carbide and monocarbide with a definite composition. This kind of ball-like powders is particularly suited for wear resistant applications. (author)

  16. Inactivation of Candida biofilms by non-thermal plasma and its enhancement for fungistatic effect of antifungal drugs.

    Directory of Open Access Journals (Sweden)

    Yi Sun

    Full Text Available We investigated the antifungal effect of non-thermal plasma, as well as its combination with common antifungal drugs, against Candida biofilms. A direct current atmospheric pressure He/O(2 (2% plasma microjet (PMJ was used to treat Candida biofilms in a 96-well plate. Inactivation efficacies of the biofilms were evaluated by XTT assay and counting colony forming units (CFUs. Morphological properties of the biofilms were evaluated by Scanning Electron Microscope (SEM. The sessile minimal inhibitory concentrations (SMICs of fluconazole, amphotericin B, and caspofungin for the biofilms were also tested. Electron Spin Resonance (ESR spectroscopy was used to detect the reactive oxygen species (ROS generated directly and indirectly by PMJ. The Candida biofilms were completely inactivated after 1 min PMJ treatment, where severely deformed fungal elements were observed in SEM images. The SMICs of the tested antifungal drugs for the plasma-treated biofilms were decreased by 2-6 folds of dilution, compared to those of the untreated controls. ROS such as hydroxyl radical ((•OH, superoxide anion radical ((•O(2 (- and singlet molecular oxygen ((1O(2 were detected by ESR. We hence conclude that He/O(2 (2% plasma alone, as well as in combination with common antifungal drugs, is able to inactivate Candida biofilms rapidly. The generation of ROS is believed to be one of the underlying mechanisms for the fungicidal activity of plasma.

  17. State-space modeling of the radio frequency inductively-coupled plasma generator

    International Nuclear Information System (INIS)

    Dewangan, Rakesh Kumar; Punjabi, Sangeeta B; Mangalvedekar, H A; Lande, B K; Joshi, N K; Barve, D N

    2010-01-01

    Computational fluid dynamics models of RF-ICP are useful in understanding the basic transport phenomenon in an ICP torch under a wide variety of operating conditions. However, these models lack the ability to evaluate the effects of the plasma condition on the RF generator. In this paper, simulation of an induction plasma generator has been done using state space modelling by considering inductively coupled plasma as a part of RF network .The time dependent response of the RF-ICP generator circuit to given input excitation has been computed by extracting the circuit's state-space variables and their constraint matrices. MATLAB 7.1 software has been used to solve the state equations. The values of RF coil current, frequency and plasma power has been measured experimentally also at different plate bias voltage. The simulated model is able to predict RF coil current, frequency, plasma power, overall efficiency of the generator. The simulated and measured values are in agreement with each other. This model can prove useful as a design tool for the Induction plasma generator.

  18. Air spark-like plasma source for antimicrobial NOx generation

    International Nuclear Information System (INIS)

    Pavlovich, M J; Galleher, C; Curtis, B; Clark, D S; Graves, D B; Ono, T; Machala, Z

    2014-01-01

    We demonstrate and analyse the generation of nitrogen oxides and their antimicrobial efficacy using atmospheric air spark-like plasmas. Spark-like discharges in air in a 1 L confined volume are shown to generate NO x at an initial rate of about 1.5  ×  10 16 NO x molecules/J dissipated in the plasma. Such a discharge operating in this confined volume generates on the order of 6000 ppm NO x in 10 min. Around 90% of the NO x is in the form of NO 2 after several minutes of operation in the confined volume, suggesting that NO 2 is the dominant antimicrobial component. The strong antimicrobial action of the NO x mixture after several minutes of plasma operation is demonstrated by measuring rates of E. coli disinfection on surfaces and in water exposed to the NO x mixture. Some possible applications of plasma generation of NO x (perhaps followed by dissolution in water) include disinfection of surfaces, skin or wound antisepsis, and sterilization of medical instruments at or near room temperature. (paper)

  19. Ion Streaming Instabilities in Pair Ion Plasma and Localized Structure with Non-Thermal Electrons

    Science.gov (United States)

    Nasir Khattak, M.; Mushtaq, A.; Qamar, A.

    2015-12-01

    Pair ion plasma with a fraction of non-thermal electrons is considered. We investigate the effects of the streaming motion of ions on linear and nonlinear properties of unmagnetized, collisionless plasma by using the fluid model. A dispersion relation is derived, and the growth rate of streaming instabilities with effect of streaming motion of ions and non-thermal electrons is calculated. A qausi-potential approach is adopted to study the characteristics of ion acoustic solitons. An energy integral equation involving Sagdeev potential is derived during this process. The presence of the streaming term in the energy integral equation affects the structure of the solitary waves significantly along with non-thermal electrons. Possible application of the work to the space and laboratory plasmas are highlighted.

  20. Ion streaming instabilities in pair ion plasma and localized structure with non-thermal electrons

    Energy Technology Data Exchange (ETDEWEB)

    Khattak, M. Nasir; Qamar, A., E-mail: mnnasirphysics@gmail.com [Department of Physics, University of Peshawar (Pakistan); Mushtaq, A. [Department of Physics, Abdul Wali Khan University Mardan, National Center for Physics, Mardan (Pakistan)

    2015-12-15

    Pair ion plasma with a fraction of non-thermal electrons is considered. We investigate the effects of the streaming motion of ions on linear and nonlinear properties of unmagnetized, collisionless plasma by using the fluid model. A dispersion relation is derived, and the growth rate of streaming instabilities with effect of streaming motion of ions and non-thermal electrons is calculated. A quasi-potential approach is adopted to study the characteristics of ion acoustic solitons. An energy integral equation involving Sagdeev potential is derived during this process. The presence of the streaming term in the energy integral equation affects the structure of the solitary waves significantly along with non-thermal electrons. Possible application of the work to the space and laboratory plasmas are highlighted. (author)

  1. Proton emission from laser-generated plasmas at different intensities

    Czech Academy of Sciences Publication Activity Database

    Torrisi, L.; Cutroneo, M.; Cavallaro, S.; Giuffrida, L.; Margarone, Daniele

    2012-01-01

    Roč. 57, č. 2 (2012), s. 237-240 ISSN 0029-5922. [International Conference on Research and Applications of Plasmas (PLASMA). Warsaw, 12.09.2011-16.09.2011] Institutional support: RVO:68378271 Keywords : laser-generated plasma * hydrogenated targets * proton acceleration Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.507, year: 2012

  2. Propagation of thermal and hydromagnetic waves in an ionizing-recombining hydrogen plasma

    International Nuclear Information System (INIS)

    Di Sigalotti, Leonardo G.; Sira, Eloy; Rendon, Otto; Tremola, Ciro; Mendoza-Briceno, Cesar A.

    2004-01-01

    The propagation of thermal and magnetohydrodynamic (MHD) waves in a heat-conducting, hydrogen plasma, threaded by an external uniform magnetic field (B) and in which photoionization and photorecombination [H + +e - H+hν(χ)] processes are progressing, is investigated here using linear analysis. The resulting dispersion equation is solved analytically for varied strength (β<<1 and ∼1) and orientation of the magnetic field, where β denotes the ratio of plasma to magnetic pressures. Application of this model to the interstellar medium shows that heat conduction governs the propagation of thermal waves only at relatively high frequencies regardless of the plasma temperature, strength, and orientation of the magnetic field. When the direction of wave propagation is held perpendicular to B (i.e., k perpendicular B), the magnetosonic phase velocity is closely Alfvenic for β<<1, while for β∼1 both the hydrostatic and magnetic pressures determine the wave velocity. As long as k parallel B, the fast (transverse) magnetosonic wave becomes an Alfven wave for all frequencies independent of the plasma temperature and field strength, while the slow (longitudinal) magnetosonic wave becomes a pure sound wave. Amplification of thermal and MHD waves always occur at low frequencies and preferentially at temperatures for which the plasma is either weakly or partially ionized. Compared to previous analysis for the same hydrogen plasma model with B=0, the presence of the magnetic field makes the functional dependence of the physical quantities span a longer range of frequencies, which becomes progressively longer as the field strength is increased

  3. Unified model of plasma formation, bubble generation and shock wave emission in water for fs to ns laser pulses (Conference Presentation)

    Science.gov (United States)

    Liang, Xiao-Xuan; Freidank, Sebastian; Linz, Norbert; Paltauf, Günther; Zhang, Zhenxi; Vogel, Alfred

    2017-03-01

    We developed modeling tools for optical breakdown events in water that span various phases reaching from breakdown initiation via solvated electron generation, through laser induced-plasma formation and temperature evolution in the focal spot to the later phases of cavitation bubble dynamics and shock wave emission and applied them to a large parameter space of pulse durations, wavelengths, and pulse energies. The rate equation model considers the interplay of linear absorption, photoionization, avalanche ionization and recombination, traces thermalization and temperature evolution during the laser pulse, and portrays the role of thermal ionization that becomes relevant for T > 3000 K. Modeling of free-electron generation includes recent insights on breakdown initiation in water via multiphoton excitation of valence band electrons into a solvated state at Eini = 6.6 eV followed by up-conversion into the conduction band level that is located at 9.5 eV. The ability of tracing the temperature evolution enabled us to link the model of laser-induced plasma formation with a hydrodynamic model of plasma-induced pressure evolution and phase transitions that, in turn, traces bubble generation and dynamics as well as shock wave emission. This way, the amount of nonlinear energy deposition in transparent dielectrics and the resulting material modifications can be assessed as a function of incident laser energy. The unified model of plasma formation and bubble dynamics yields an excellent agreement with experimental results over the entire range of investigated pulse durations (femtosecond to nanosecond), wavelengths (UV to IR) and pulse energies.

  4. Treatment of the oily waste sludges through thermal plasma in absence of oxygen

    International Nuclear Information System (INIS)

    Castaneda J, G.; Pacheco S, J.

    2001-01-01

    The thermal plasma process in absence of oxygen for the degradation of oily waste sludges was evaluated. These residues are commonly generated in the petrochemical industry and are considered hazardous wastes according to the present environmental regulations. The process was operated using difference residence times and the characteristics of the gaseous by products and residual soils were determined. The efficiency of organic matter degradation was 99.99%. The attained volume reduction, under the best conditions was 95.5%. The residual soils were composed of carbon and clays. The residual gases have low molecular weight. The resulting final wastes were non-hazardous and could be disposed of in landfills. (Author)

  5. Rocket-borne thermal plasma instrument "MIPEX" for the ionosphere D, E layer in-situ measurements

    Science.gov (United States)

    Fang, H. K.; Chen, A. B. C.; Lin, C. C. H.; Wu, T. J.; Liu, K. S.; Chuang, C. W.

    2017-12-01

    In this presentation, the design concepts, performances and status of a thermal plasma particle instrument package "Mesosphere and Ionosphere Plasma Exploration complex (MIPEX)", which is going to be installed onboard a NSPO-funded hybrid rocket, to investigate the electrodynamic processes in ionosphere D, E layers above Taiwan are reported. MIPEX is capable of measuring plasma characteristics including ion temperature, ion composition, ion drift, electron temperature and plasma density at densities as low as 1-10 cm-1. This instrument package consists of an improved retarding potential analyzer with a channel electron multiplier (CEM), a simplified ion drift meter and a planar Langmuir probe. To achieve the working atmospheric pressure of CEM at the height of lower D layer ( 70km), a portable vacuum pump is also placed in the package. A prototype set of the MIPEX has been developed and tested in the Space Plasma Operation Chamber (SPOC) at NCKU, where in ionospheric plasma is generated by back-diffusion plasma sources. A plasma density of 10-106 cm-1, ion temperature of 300-1500 K and electron temperature of 1000-3000K is measured and verified. Limited by the flight platform and the performance of the instruments, the in-situ plasma measurements at the Mesosphere and lower Thermosphere is very challenging and rare. MIPEX is capable of extending the altitude of the effective plasma measurement down to 70 km height and this experiment can provide unique high-quality data of the plasma environment to explore the ion distribution and the electrodynamic processes in the Ionosphere D, E layers at dusk.

  6. Comparison of plasma generated nitrogen fertilizer to conventional fertilizers ammonium nitrate and sodium nitrate for pre-emergent and seedling growth

    Science.gov (United States)

    Andhavarapu, A.; King, W.; Lindsay, A.; Byrns, B.; Knappe, D.; Fonteno, W.; Shannon, S.

    2014-10-01

    Plasma source generated nitrogen fertilizer is compared to conventional nitrogen fertilizers in water for plant growth. Root, shoot sizes, and weights are used to examine differences between plant treatment groups. With a simple coaxial structure creating a large-volume atmospheric glow discharge, a 162 MHz generator drives the air plasma. The VHF plasma source emits a steady state glow; the high drive frequency is believed to inhibit the glow-to-arc transition for non-thermal discharge generation. To create the plasma activated water (PAW) solutions used for plant treatment, the discharge is held over distilled water until a 100 ppm nitrate aqueous concentration is achieved. The discharge is used to incorporate nitrogen species into aqueous solution, which is used to fertilize radishes, marigolds, and tomatoes. In a four week experiment, these plants are watered with four different solutions: tap water, dissolved ammonium nitrate DI water, dissolved sodium nitrate DI water, and PAW. Ammonium nitrate solution has the same amount of total nitrogen as PAW; sodium nitrate solution has the same amount of nitrate as PAW. T-tests are used to determine statistical significance in plant group growth differences. PAW fertilization chemical mechanisms are presented.

  7. Application of a plasma-jet for skin antisepsis: analysis of the thermal action of the plasma by laser scanning microscopy

    International Nuclear Information System (INIS)

    Lademann, O; Kramer, A; Richter, H; Patzelt, A; Alborova, A; Humme, D; Weltmann, K-D; Hartmann, B; Hinz, P; Koch, S

    2010-01-01

    Recently, it was reported that a plasma-jet could be efficiently applied for the antisepsis of wounds. In this case, the discharge in an argon gas stream was used to produce a so-called ''cold plasma'' on the skin surface. The thermal action of the plasma on the skin was investigated in the present study by means of laser scanning microscopy (LSM) and by histological analysis. Consequently, the plasma beam was moved with a definite velocity at an optimal distance over the skin surface. The structural changes of the tissue were analyzed. It was found by LSM that a thermal damage could be detected only in the upper cell layers of the stratum corneum (SC) at moving velocities of the plasma beam, usually applied in clinical practice. Deeper parts of the SC were not damaged. The structural changes were so superficial that they could be detected only by LSM but not by analysis of the histological sections

  8. Synthesis of nanocrystalline magnesium nitride (Mg3N2) powder using thermal plasma

    International Nuclear Information System (INIS)

    Kim, Dong-Wook; Kim, Tae-Hee; Park, Hyun-Woo; Park, Dong-Wha

    2011-01-01

    Nanocrystalline magnesium nitride (Mg 3 N 2 ) powder was synthesized from bulk magnesium by thermal plasma at atmospheric pressure. Magnesium vapor was generated through heating the bulk magnesium by DC plasma jet and reacted with ammonia gas. Injecting position and flow rates of ammonia gas were controlled to investigate an ideal condition for Mg 3 N 2 synthesis. The synthesized Mg 3 N 2 was cooled and collected on the chamber wall. Characteristics of the synthesized powders for each experimental condition were analyzed by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and thermogravity analysis (TGA). In absence of NH 3 , magnesium metal powder was formed. The synthesis with NH 3 injection in low temperature region resulted in a formation of crystalline magnesium nitride with trigonal morphology, whereas the mixture of magnesium metal and amorphous Mg 3 N 2 was formed when NH 3 was injected in high temperature region. Also, vaporization process of magnesium was discussed.

  9. Characteristics of ceramic oxide nanoparticles synthesized using radio frequency produced thermal plasma

    International Nuclear Information System (INIS)

    Dhamale, Gayatri D.; Mathe, V.L.; Bhoraskar, S.V.; Ghorui, S.

    2015-01-01

    Thermal plasma devices with their unique processing capabilities due to extremely high temperature and steep temperature gradient play an important role in synthesis of ultrafine powders in the range of 100nm or less. High temperature gas phase synthesis in Radio Frequency (RF) thermal plasma reactor is an attractive route for mass production of refractory nanoparticles, especially in the case of rare earth oxides. Here we report synthesis of Yttrium Oxide (Y_2O_3), Neodymium Oxide (Nd_2O_3) and Aluminum Oxide (Al_2O_3) in an inductively coupled radio frequency thermal plasma reactor. Synthesized nanoparticles find wide application in various fields like gate dielectrics, photocatalytic applications, laser devices and photonics. Nano sized Yttrium oxide, Neodymium Oxide and Aluminum oxide powders were separately synthesized in an RF plasma reactor starting with micron sized irregular shaped precursor powders. The system was operated at 3MHz in atmospheric pressure at different power levels. Synthesized powders were scrapped out from different deposition locations inside the reactor and characterized for their phase, morphology, particle size, crystallinity and other characteristic features. Highly crystalline nature of the synthesized particles, narrow size distribution, location dependent phase formation, and distinct variation in the inherent defect states compared to the bulk are some of the important characteristic features observed

  10. Apparatus and method for thermal power generation

    International Nuclear Information System (INIS)

    Cohen, P.; Redding, A.H.

    1978-01-01

    An improved thermal power plant and method of power generation is described which minimizes thermal stress and chemical impurity buildup in the vaporizing component, particularly beneficial under loss of normal feed fluid and startup conditions. The invention is particularly applicable to a liquid metal fast breeder reactor plant

  11. Multiprobe characterization of plasma flows for space propulsion

    NARCIS (Netherlands)

    Damba, Julius; Argente, P.; Maldonado, P. E.; Cervone, A.; Domenech-Garret, J.L.; Conde, Luis

    2018-01-01

    Plasma engines for space propulsion generate plasma jets (also denominated plasma plumes) having supersonic ion groups with typical speeds in the order of tens of kilometers per second, which lies between electron and ion thermal speeds. Studies of the stationary plasma expansion process using a

  12. Acid gas degradation by non-thermal plasma and energy estimation

    International Nuclear Information System (INIS)

    Valdivia-Barrientos, R; Pacheco-Sotelo, J; Pacheco-Pacheco, M; Rivera-Rodríguez, C; Ibañez-Olvera, M; Estrada-Martinez, N; Silva-Rosas, J

    2012-01-01

    This paper describes a method to estimate the energy efficiency in the system performed to treat acid gases by plasma discharges. The electrical energy consumed by the plasma is evaluated by an electrical diagnosis, taking into account the experimental voltage and current applied to the power source. The estimation of the electrical energy generated by solid oxide fuel cells is based on the method of modeling the energy produced by the species generated by the plasma discharge and taking also into account the temperature of the gases.

  13. Pyrite-enhanced methylene blue degradation in non-thermal plasma water treatment reactor

    Energy Technology Data Exchange (ETDEWEB)

    Benetoli, Luis Otavio de Brito, E-mail: luskywalcker@yahoo.com.br [Departamento de Quimica, Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Cadorin, Bruno Mena; Baldissarelli, Vanessa Zanon [Departamento de Quimica, Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Geremias, Reginaldo [Departamento de Ciencias Rurais, Universidade Federal de Santa Catarina (UFSC), Curitibanos, SC (Brazil); Goncalvez de Souza, Ivan [Departamento de Quimica, Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Debacher, Nito Angelo, E-mail: debacher@qmc.ufsc.br [Departamento de Quimica, Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2012-10-30

    Highlights: Black-Right-Pointing-Pointer We use O{sub 2} as the feed gas and pyrite was added to the non-thermal plasma reactor. Black-Right-Pointing-Pointer The methylene blue removal by NTP increased in the presence of pyrite. Black-Right-Pointing-Pointer The total organic carbon content decreased substantially. Black-Right-Pointing-Pointer The acute toxicity test showed that the treated solution is not toxic. Black-Right-Pointing-Pointer The dye degradation occurs via electron impact as well as successive hydroxylation. - Abstract: In this study, methylene blue (MB) removal from an aqueous phase by electrical discharge non-thermal plasma (NTP) over water was investigated using three different feed gases: N{sub 2}, Ar, and O{sub 2}. The results showed that the dye removal rate was not strongly dependent on the feed gas when the electrical current was kept the same for all gases. The hydrogen peroxide generation in the water varied according to the feed gas (N{sub 2} < Ar < O{sub 2}). Using O{sub 2} as the feed gas, pyrite was added to the reactor in acid medium resulting in an accentuated increase in the dye removal, which suggests that pyrite acts as a Fenton-like catalyst. The total organic carbon (TOC) content of the dye solution decreased slightly as the plasma treatment time increased, but in the presence of the pyrite catalyst the TOC removal increased substantially. The acute toxicity test using Artemia sp. microcrustaceans showed that the treated solution is not toxic when Ar, O{sub 2} or O{sub 2}-pyrite is employed. Electrospray ionization mass spectrometry analysis (ESI-MS) of the treated samples indicated that the dye degradation occurs via high energy electron impact as well as successive hydroxylation in the benzene rings of the dye molecules.

  14. Plasma waveguides: Addition of end funnels and generation in clustered gases

    International Nuclear Information System (INIS)

    Kim, K.Y.; Alexeev, I.; Fan, J.; Parra, E.; Milchberg, H.M.

    2002-01-01

    We present results from some recent experiments: the generation of a plasma funnel for improved pump pulse input coupling to plasma waveguides, and the development of a single shot transient phase diagnostic with 15 fs temporal resolution. The phase diagnostic is used in two experiments. We first demonstrate that short pulse heated clustered gases can act as an optical guiding medium and are highly absorbing. We show that this leads to a method for plasma waveguide generation at densities substantially lower than current typical values. Second, we measure transient phase shifts generated by intense pump pulses injected into plasma waveguides

  15. Performance of plasma facing materials under intense thermal loads in tokamaks and stellarators

    Energy Technology Data Exchange (ETDEWEB)

    Linke, J.; Hirai, T.; Roedig, M.; Singheiser, L. [Forschungszentrum Juelich GmbH, EURATOM Association, Juelich (Germany)

    2003-07-01

    Beside quasi-stationary plasma operation, short transient thermal pulses with deposited energy densities in the order of several ten MJm{sup -2} are a serious concern for next step devices, in particular for tokamak devices such as ITER. The most serious of these transient events are plasma disruptions. Here a considerable fraction of the plasma energy is deposited on a localized surface area in the divertor strike zone region; the time scale of these events is typically in the order of 1 ms. In spite of the fact that a dense cloud of ablation vapour will form above the strike zone, only partial shielding of the divertor armour from incident plasma particles will occur. As a consequence, thermal shock induced crack formation, vaporization, surface melting, melt layer ejection, and particle emission induced by brittle destruction processes will limit the lifetime of the components. In addition, dust particles (neutron activated metals or tritium enriched carbon) are a serious concern form a safety point of view. Other transient heat loads which occasionally occur in magnetic confinement experiments such as instabilities in the plasma positioning (vertical displacement events) also may cause irreversible damage to plasma facing components (PFC), particularly to metals such as beryllium and tungsten. Another serious damage to PFCs is due to intense fluxes of 14 MeV neutrons in D-T-burning plasma devices. Integrated neutron fluence of several ten dpa in future thermonuclear fusion reactors will degrade essential physical properties of the components (e.g. thermal conductivity); another serious concern is the embrittlement of the heat sink and the plasma facing materials (PFM). (orig.)

  16. Generation and confinement of hot ions and electrons in a reversed-field pinch plasma

    International Nuclear Information System (INIS)

    Chapman, B E; Almagri, A F; Anderson, J K; Caspary, K J; Clayton, D J; Den Hartog, D J; Ennis, D A; Fiksel, G; Gangadhara, S; Kumar, S; Magee, R M; O'Connell, R; Parke, E; Prager, S C; Reusch, J A; Sarff, J S; Stephens, H D; Brower, D L; Ding, W X; Craig, D

    2010-01-01

    By manipulating magnetic reconnection in Madison Symmetric Torus (MST) discharges, we have generated and confined for the first time a reversed-field pinch (RFP) plasma with an ion temperature >1 keV and an electron temperature of 2 keV. This is achieved at a toroidal plasma current of about 0.5 MA, approaching MST's present maximum. The manipulation begins with intensification of discrete magnetic reconnection events, causing the ion temperature to increase to several kiloelectronvolts. The reconnection is then quickly suppressed with inductive current profile control, leading to capture of a portion of the added ion heat with improved ion energy confinement. Electron energy confinement is simultaneously improved, leading to a rapid ohmically driven increase in the electron temperature. A steep electron temperature gradient emerges in the outer region of the plasma, with a local thermal diffusivity of about 2 m 2 s -1 . The global energy confinement time reaches 12 ms, the largest value yet achieved in the RFP and which is roughly comparable to the H-mode scaling prediction for a tokamak with the same plasma current, density, heating power, size and shape.

  17. Porous materials produced from incineration ash using thermal plasma technology.

    Science.gov (United States)

    Yang, Sheng-Fu; Chiu, Wen-Tung; Wang, To-Mai; Chen, Ching-Ting; Tzeng, Chin-Ching

    2014-06-01

    This study presents a novel thermal plasma melting technique for neutralizing and recycling municipal solid waste incinerator (MSWI) ash residues. MSWI ash residues were converted into water-quenched vitrified slag using plasma vitrification, which is environmentally benign. Slag is adopted as a raw material in producing porous materials for architectural and decorative applications, eliminating the problem of its disposal. Porous materials are produced using water-quenched vitrified slag with Portland cement and foaming agent. The true density, bulk density, porosity and water absorption ratio of the foamed specimens are studied here by varying the size of the slag particles, the water-to-solid ratio, and the ratio of the weights of the core materials, including the water-quenched vitrified slag and cement. The thermal conductivity and flexural strength of porous panels are also determined. The experimental results show the bulk density and the porosity of the porous materials are 0.9-1.2 g cm(-3) and 50-60%, respectively, and the pore structure has a closed form. The thermal conductivity of the porous material is 0.1946 W m(-1) K(-1). Therefore, the slag composite materials are lightweight and thermal insulators having considerable potential for building applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Thermal consequences of plasma disruptions in TFTR and ETF

    International Nuclear Information System (INIS)

    Budny, R.; Ludescher, C.

    1981-01-01

    We studied thermal responses of first walls for TFTR and ETF during plasma disruptions. To model the flux, we assumed the entire kinetic energy is deposited by axisymmetric horizontal displacement of the plasma. The deposition time is a free parameter. In TFTR, the minimum deposition time which does not cause the toroidal limiter to melt is 7 or 14 ms depending on whether or not the limiter is actively cooled. In ETF, the minimum time which does not cause surface melting of the cooling tubes is 80 ms. (author)

  19. Generation of plasma rotation by ICRH in tokamaks

    International Nuclear Information System (INIS)

    Chang, C.; Phillips, C.K.; White, R.B.; Zweben, S.; Bonoli, P.T.; Rice, J.; Greenwald, M.; Grassie, J.S. de

    2001-01-01

    A physical mechanism to generate plasma rotation by ICRH is presented in a tokamak geometry. By breaking the omnigenity of resonant ion orbits, ICRH can induce a non-ambipolar minor-radial flow of resonant ions. This induces a return current j p r in the plasma, which then drives plasma rotation through the j p r xB force. It is estimated that the fast-wave power in the present-day tokamak experiments can be strong enough to give a significant modification to plasma rotation. (author)

  20. Status of thermal power generation in India-Perspectives on capacity, generation and carbon dioxide emissions

    International Nuclear Information System (INIS)

    Ghosh, Subhodip

    2010-01-01

    India's reliance on fossil-fuel based electricity generation has aggravated the problem of high carbon dioxide (CO 2 ) emissions from combustion of fossil fuels, primarily coal, in the country's energy sector. The objective of this paper is to analyze thermal power generation in India for a four-year period and determine the net generation from thermal power stations and the total and specific CO 2 emissions. The installed generating capacity, net generation and CO 2 emissions figures for the plants have been compared and large generators, large emitters, fuel types and also plant vintage have been identified. Specific emissions and dates of commissioning of plants have been taken into account for assessing whether specific plants need to be modernized. The focus is to find out areas and stations which are contributing more to the total emissions from all thermal power generating stations in the country and identify the overall trends that are emerging.

  1. Thermal responses of tokamak reactor first walls during cyclic plasma burns

    International Nuclear Information System (INIS)

    Smith, D.L.; Charak, I.

    1978-01-01

    The CINDA-3G computer code has been adapted to analyze the thermal responses and operating limitations of two fusion reactor first-wall concepts under normal cyclic operation. A component of an LMFBR computer code has been modified and adapted to analyze the ablative behavior of first-walls after a plasma disruption. The first-wall design concepts considered are a forced-circulation water-cooled stainless steel panel with and without a monolithic graphite liner. The thermal gradients in the metal wall and liner have been determined for several burn-cycle scenarios and the extent of surface ablation that results from a plasma disruption has been determined for stainless steel and graphite first surfaces

  2. Thermal responses of tokamak reactor first walls during cyclic plasma burns

    International Nuclear Information System (INIS)

    Smith, D.L.; Charak, I.

    1977-01-01

    The CINDA-3G computer code has been adapted to analyze the thermal responses and operating limitations of two fusion reactor first-wall concepts under normal cyclic operation. A component of an LMFBR computer has been modified and adapted to analyze the ablative behavior of first-walls after a plasma disruption. The first-wall design concepts considered are a forced-circulation water-cooled stainless steel panel with and without a monolithic graphite liner. The thermal gradients in the metal wall and liner have been determined for several burn-cycle scenarios and the extent of surface ablation that results from a plasma disruption has been determined for stainless steel and graphite first surfaces

  3. The effect of electron thermal conduction on plasma pressure gradient during reconnection of magnetic field lines

    International Nuclear Information System (INIS)

    Chu, T.K.

    1987-12-01

    The interplay of electron cross-field thermal conduction and the reconnection of magnetic field lines around an m = 1 magnetic island prior to a sawtooth crash can generate a large pressure gradient in a boundary layer adjacent to the reconnecting surface, leading to an enhanced gradient of poloidal beta to satisfy the threshold condition for ideal MHD modes. This narrow boundary layer and the short onset time of a sawtooth crash can be supported by fine-grained turbulent processes in a tokamak plasma. 11 refs

  4. Surface plasma source with saddle antenna radio frequency plasma generator.

    Science.gov (United States)

    Dudnikov, V; Johnson, R P; Murray, S; Pennisi, T; Piller, C; Santana, M; Stockli, M; Welton, R

    2012-02-01

    A prototype RF H(-) surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA∕kW. Control experiments with H(-) beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.

  5. Generation mechanism and properties of plasma double layers

    International Nuclear Information System (INIS)

    Sanduloviciu, M.; Lozneanu, E.

    1985-01-01

    The generation mechanism of plasma double layers is studied surveying the results of some experiments. The main mechanism is the same in the cases of collisional and collisionless plasmas. Inelastic quantum collision processes taking place between plasma electrons, accelerated in a local field up to near the same oriented velocity and the neutral particles of the background gases create the necessary conditions for double layer formation. (D.Gy.)

  6. Destruction studies of hazardous wastes by thermal plasma

    International Nuclear Information System (INIS)

    Cota S, G.

    1998-01-01

    Plasma technology appears promising because its high degree of controllability, capability to process waste without the adverse effects of combustion, and a very wide temperature range of operation. The goal of this work was to develop a process for a high throughput system to turn hazardous waste into inert stable products, which can be safely stored and to greatly reduce air pollution relative to incineration. The experiments have shown that the thermal plasma reactor can provide a high degree of decomposition of CCl 4 , C 6 H 6 , C 2 Cl 4 and commercial oil at low gas input speeds, with modest power requirements. Decomposition of 99.9999 % has been obtained in our laboratory and all the organic components are decomposed in base molecules (C, CO, CO 2 , H 2 , HCl). The analysis of exhaust gases was made by using a mass filter quadrupole. The equipment consist of a cylindrical reactor hermetically sealed, double-walled and water-cooled container made of special steel, this container in halt the crucible which serves to receive the waste materials. The whole system is designed for a maximal internal temperature of 2000 Centigrade. The gaseous result components of the material are transferred to a scrubber unit through an exit arranged on the top of reactor. The thermal efficiency evaluation of the plasma torch was also realized, obtaining a reasonable agreement between measurements and predictions in temperature profiles. (Author)

  7. Toluene degradation by non-thermal plasma combined with a ferroelectric catalyst.

    Science.gov (United States)

    Liang, Wen-Jun; Ma, Lin; Liu, Huan; Li, Jian

    2013-08-01

    Degradation of toluene in a gas by non-thermal plasma with a ferroelectric catalyst was studied at normal temperature and atmospheric pressure. Spontaneous polarization material (BaTiO3) and photocatalyst (TiO2) were added into plasma system simultively. Toluene degradation efficiency and specific energy density during the discharge process were investigated. Furthermore, byproducts and degradation mechanisms of toluene were also investigated. The toluene degradation efficiency increased when non-thermal plasma technology was combined with the catalyst. The toluene degradation efficiencies of the different catalysts tested were in the following order: BaTiO3/TiO2>BaTiO3>TiO2>no catalyst. A mass ratio of 2.38:1 was optimum for the BaTiO3 and TiO2 catalyst. The outlet gas was analyzed by gas chromatography and Fourier transform infrared spectroscopy, and the main compounds detected were CO2, H2O, O3 and benzene ring derivatives. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Time-resolved probing of electron thermal conduction in femtosecond-laser-pulse-produced plasmas

    International Nuclear Information System (INIS)

    Vue, B.T.V.

    1993-06-01

    We present time-resolved measurements of reflectivity, transmissivity and frequency shifts of probe light interacting with the rear of a disk-like plasma produced by irradiation of a transparent solid target with 0.1ps FWHM laser pulses at peak intensity 5 x 10 l4 W/CM 2 . Experimental results show a large increase in reflection, revealing rapid formation of a steep gradient and overdense surface plasma layer during the first picosecond after irradiation. Frequency shifts due to a moving ionization created by thermal conduction into the solid target are recorded. Calculations using a nonlinear thermal heat wave model show good agreement with the measured frequency shifts, further confining the strong thermal transport effect

  9. Novel fragmentation model for pulverized coal particles gasification in low temperature air thermal plasma

    Directory of Open Access Journals (Sweden)

    Jovanović Rastko D.

    2016-01-01

    Full Text Available New system for start-up and flame support based on coal gasification by low temperature air thermal plasma is planned to supplement current heavy oil system in Serbian thermal power plants in order to decrease air pollutions emission and operational costs. Locally introduced plasma thermal energy heats up and ignites entrained coal particles, thus starting chain process which releases heat energy from gasified coal particles inside burner channel. Important stages during particle combustion, such as particle devolatilisation and char combustion, are described with satisfying accuracy in existing commercial CFD codes that are extensively used as powerful tool for pulverized coal combustion and gasification modeling. However, during plasma coal gasification, high plasma temperature induces strong thermal stresses inside interacting coal particles. These stresses lead to “thermal shock” and extensive particle fragmentation during which coal particles with initial size of 50-100 m disintegrate into fragments of at most 5-10 m. This intensifies volatile release by a factor 3-4 and substantially accelerates the oxidation of combustible matter. Particle fragmentation, due to its small size and thus limited influence on combustion process is commonly neglected in modelling. The main focus of this work is to suggest novel approach to pulverized coal gasification under high temperature conditions and to implement it into commercial comprehensive code ANSYS FLUENT 14.0. Proposed model was validated against experimental data obtained in newly built pilot scale D.C plasma burner test facility. Newly developed model showed very good agreement with experimental results with relative error less than 10%, while the standard built-in gasification model had error up to 25%.

  10. DC Thermal Plasma Design and Utilization for the Low Density Polyethylene to Diesel Oil Pyrolysis Reaction

    Directory of Open Access Journals (Sweden)

    Hossam A. Gabbar

    2017-06-01

    Full Text Available The exponential increase of plastic production produces 100 million tonnes of waste plastics annually which could be converted into hydrocarbon fuels in a thermal cracking process called pyrolysis. In this research work, a direct current (DC thermal plasma circuit is designed and used for conversion of low density polyethylene (LDPE into diesel oil in a laboratory scale pyrolysis reactor. The experimental setup uses a 270 W DC thermal plasma at operating temperatures in the range of 625 °C to 860 °C for a low density polyethylene (LDPE pyrolysis reaction at pressure = −0.95, temperature = 550 °C with τ = 30 min at a constant heating rate of 7.8 °C/min. The experimental setup consists of a vacuum pump, closed system vessel, direct current (DC plasma circuit, and a k-type thermocouple placed a few millimeters from the reactant sample. The hydrocarbon products are condensed to diesel oil and analyzed using flame ionization detector (FID gas chromatography. The analysis shows 87.5% diesel oil, 1,4-dichlorobenzene (Surr, benzene, ethylbenzene and traces of toluene and xylene. The direct current (DC thermal plasma achieves 56.9 wt. % of diesel range oil (DRO, 37.8 wt. % gaseous products and minimal tar production. The direct current (DC thermal plasma shows reliability, better temperature control, and high thermal performance as well as the ability to work for long operation periods.

  11. On the electric and magnetic field generation in expanding plasmas

    International Nuclear Information System (INIS)

    Gielen, H.J.G.

    1989-01-01

    This thesis deals with the generation of electric and magnetic fields in expanding plasmas. The theoretical model used to calculate the different field quantities in such plasmas is discussed in part 1 and is in fact an analysis of Ohm's law. A general method is given that decomposes each of the forces terms in Ohm's law in a component that induces a charge separation in the plasma and in a component that can drive current. This decomposition is unambiguous and depends upon the boundary conditions for the electric potential. It is shown that in calculating the electromagnetic field quantities in a plasma that is located in the vicinity of a boundary that imposes constraints on the electric potential, Ohm's law should be analyzed instead of the so-called induction equation. Three applications of the model are presented. A description is given of the unipolar arc discharge where both plasma and sheath effects have been taken into account. Secondly a description is presented of the plasma effects of a cathode spot. The third application of the model deals with the generation of magnetic fields in laser-produced plasmas. The second part of this thesis describes the experiments on a magnetized argon plasma expanding from a cascaded arc. With the use of spectroscopic techniques the electron density, ion temperature and the rotation velocity profiles of the ion gas have been determined. The magnetic field generated by the plasma has been measured with the use of the Zeeman effect. Depending on the channel diameter of the nozzle of the cascaded arc, self-generated magnetic fields with axial components of the order of 1% of the externally applied mangetic field have been observed. From the measured ion rotation it has been concluded that this magnetic field is mainly generated by azimuthal electron currents. The corresponding azimuthal current density is of the order of 15% of the axial current density. The observed ion rotation is caused by electron-ion friction. (author

  12. Expected energy fluxes onto ITER Plasma Facing Components during disruption thermal quenches from multi-machine data comparisons

    International Nuclear Information System (INIS)

    Loarte, A.; Andrew, P.; Matthews, G.F.; Paley, J.; Riccardo, V.; Counsell, G.; Eich, T.; Fuchs, C.; Gruber, O.; Herrmann, A.; Pautasso, G.; Federici, G.; Finken, K.H.; Maddaluno, G.; Whyte, D.

    2005-01-01

    A comparison of the power flux characteristics during the thermal quench of plasma disruptions among various tokamak experiments has been carried out and conclusions for ITER have been drawn. It is generally observed that the energy of the plasma at the thermal quench is much smaller than that of a full performance plasma. The timescales for power fluxes onto PFCs during the thermal quench, as determined by IR measurements, are found to scale with device size but not to correlate with pre-disruptive plasma characteristics. The profiles of the thermal quench power fluxes are very broad for diverted discharges, typically a factor of 5-10 broader than that measured during 'normal' plasma operation, while for limiter discharges this broadening is absent. The combination of all the above factors is used to derive the expected range of power fluxes on the ITER divertor target during the thermal quench. The new extrapolation derived in this paper indicates that the average disruption in ITER will deposit an energy flux approximately one order of magnitude lower than previously thought. The evaluation of the ITER divertor lifetime with these revised specifications is carried out. (author)

  13. Studies for determining thermal ion extraction potential for aluminium plasma generated by electron beam evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V Dileep; Barnwal, Tripti A; Mukherjee, Jaya; Gantayet, L M, E-mail: dileepv@barc.gov.i [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2010-02-01

    For effective evaporation of refractory metal, electron beam is found to be most suitable vapour generator source. Using electron beam, high throughput laser based purification processes are carried out. But due to highly concentrated electron beam, the vapour gets ionised and these ions lead to dilution of the pure product of laser based separation process. To estimate the concentration of these ions and extraction potential requirement to remove these ions from vapour stream, experiments have been conducted using aluminium as evaporant. The aluminium ingots were placed in water cooled copper crucible. Inserts were used to hold the evaporant, in order to attain higher number density in the vapour processing zone and also for confining the liquid metal. Parametric studies with beam power, number density and extraction potential were conducted. In this paper we discuss the trend of the generation of thermal ions and electrostatic field requirement for extraction.

  14. Study of single and binary ion plasma expansion into laboratory-generated plasma wakes

    International Nuclear Information System (INIS)

    Wright, K.H. Jr.

    1988-02-01

    Plasma expansion into the wake of a large rectangular plate immersed in a collisionless, supersonic plasma was investigated in laboratory experiments. The experimental conditions address both single ion and binary ion plasma flows for the case of a body whose size is large in comparison with the Debye length, when the potential difference between the body and the plasma is relatively small. A new plasma source was developed to generate equi-velocity, binary ion plasma flows, which allows access to new parameter space that have previously been unavailable for laboratory studies. Specifically, the new parameters are the ionic mass ratio and the ionic component density ratio. In a series of experiments, a krypton-neon plasma is employed where the ambient density ratio of neon to krypton is varied more than an order of magnitude. The expansion in both the single ion and binary ion plasma cases is limited to early times, i.e., a few ion plasma periods, by the combination of plasma density, plasma drift speed, and vacuum chamber size, which prevented detailed comparison with self-similar theory

  15. Plasma X-ray sources powered by megajoule magnetocumulative generators

    Energy Technology Data Exchange (ETDEWEB)

    Popkov, N F; Averchenkov, V Ya; Pikar` , A S; Ryaslov, E A; Kargin, V I; Lazarev, S A; Borodkov, V V; Nazarenko, S T; Makartsev, G F [All-Russian Research Inst. of Experimental Physics, Sarov (Russian Federation). Russian Federal Nuclear Center

    1997-12-31

    Experiments using magnetocumulative generators (MCGs) were performed to power three different types of high-energy-density plasma discharges suitable for intense x-ray generation. These included the H-pressed discharge, the capillary z-pinch, and the {theta}-pinch. The MCGs were operated both with and without plasma opening switches. The characteristic currents were approximately 10 MA and characteristic time scales approximately 1 {mu}s. (author). 7 figs., 3 refs.

  16. A novel approach to generate random surface thermal loads in piping

    Energy Technology Data Exchange (ETDEWEB)

    Costa Garrido, Oriol, E-mail: oriol.costa@ijs.si; El Shawish, Samir; Cizelj, Leon

    2014-07-01

    Highlights: • Approach for generating continuous and time-dependent random thermal fields. • Temperature fields simulate fluid mixing thermal loads at fluid–wall interface. • Through plane-wave decomposition, experimental temperature statistics are reproduced. • Validation of the approach with a case study from literature. • Random surface thermal loads generation for future thermal fatigue analyses of piping. - Abstract: There is a need to perform three-dimensional mechanical analyses of pipes, subjected to complex thermo-mechanical loadings such as the ones evolving from turbulent fluid mixing in a T-junction. A novel approach is proposed in this paper for fast and reliable generation of random thermal loads at the pipe surface. The resultant continuous and time-dependent temperature fields simulate the fluid mixing thermal loads at the fluid–wall interface. The approach is based on reproducing discrete fluid temperature statistics, from experimental readings or computational fluid dynamic simulation's results, at interface locations through plane-wave decomposition of temperature fluctuations. The obtained random thermal fields contain large scale instabilities such as cold and hot spots traveling at flow velocities. These low frequency instabilities are believed to be among the major causes of the thermal fatigue in T-junction configurations. The case study found in the literature has been used to demonstrate the generation of random surface thermal loads. The thermal fields generated with the proposed approach are statistically equivalent (within the first two moments) to those from CFD simulations results of similar characteristics. The fields maintain the input data at field locations for a large set of parameters used to generate the thermal loads. This feature will be of great advantage in future sensitivity fatigue analyses of three-dimensional pipe structures.

  17. A novel approach to generate random surface thermal loads in piping

    International Nuclear Information System (INIS)

    Costa Garrido, Oriol; El Shawish, Samir; Cizelj, Leon

    2014-01-01

    Highlights: • Approach for generating continuous and time-dependent random thermal fields. • Temperature fields simulate fluid mixing thermal loads at fluid–wall interface. • Through plane-wave decomposition, experimental temperature statistics are reproduced. • Validation of the approach with a case study from literature. • Random surface thermal loads generation for future thermal fatigue analyses of piping. - Abstract: There is a need to perform three-dimensional mechanical analyses of pipes, subjected to complex thermo-mechanical loadings such as the ones evolving from turbulent fluid mixing in a T-junction. A novel approach is proposed in this paper for fast and reliable generation of random thermal loads at the pipe surface. The resultant continuous and time-dependent temperature fields simulate the fluid mixing thermal loads at the fluid–wall interface. The approach is based on reproducing discrete fluid temperature statistics, from experimental readings or computational fluid dynamic simulation's results, at interface locations through plane-wave decomposition of temperature fluctuations. The obtained random thermal fields contain large scale instabilities such as cold and hot spots traveling at flow velocities. These low frequency instabilities are believed to be among the major causes of the thermal fatigue in T-junction configurations. The case study found in the literature has been used to demonstrate the generation of random surface thermal loads. The thermal fields generated with the proposed approach are statistically equivalent (within the first two moments) to those from CFD simulations results of similar characteristics. The fields maintain the input data at field locations for a large set of parameters used to generate the thermal loads. This feature will be of great advantage in future sensitivity fatigue analyses of three-dimensional pipe structures

  18. Thermal-hydraulic characteristic of the PGV-1000 steam generator

    International Nuclear Information System (INIS)

    Ubra, O.; Doubek, M.

    1995-01-01

    Horizontal steam generators are typical parts of nuclear power plants with pressure water reactor type VVER. By means of this computer program, a detailed thermal-hydraulic study of the horizontal steam generator PGV-1000 has been carried out and a special attention has been paid to the thermal-hydraulics of the secondary side. A set of important steam generator characteristics has been obtained and analyzed. Some of the interesting results of the analysis are presented in the paper. (author)

  19. Diagnostics of Plasma Jet Generated in Water/Argon DC Arc Torch.

    Czech Academy of Sciences Publication Activity Database

    Hurba, Oleksiy; Hlína, Michal; Hrabovský, Milan

    2016-01-01

    Roč. 3, č. 1 (2016), s. 5-8 ISSN 2336-2626. [Symposium on Physics of Switching Arc 2015, FSO 2015 /21./. Nové Město na Moravě, 07.09.2015-11.09.2015] R&D Projects: GA ČR(CZ) GA15-19444S Institutional support: RVO:61389021 Keywords : thermal plasma jet * electric probes * schlieren photography * enthalpy probe Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics)

  20. Non thermal plasma surface cleaner and method of use

    KAUST Repository

    Neophytou, Marios

    2017-09-14

    Described herein are plasma generation devices and methods of use of the devices. The devices can be used for the cleaning of various surfaces and/or for inhibiting or preventing the accumulation of particulates, such as dust, or moisture on various surfaces. The devices can be used to remove dust and other particulate contaminants from solar panels and windows, or to avoid or minimize condensation on various surfaces. In an embodiment a plasma generation device is provided. The plasma generation device can comprise: a pair of electrodes (1,2) positioned in association with a surface of a dielectric substrate (3). The pair of electrodes (1,2) can comprise a first electrode (1) and a second electrode (2). The first electrode and second electrode can be of different sizes, one of the electrodes being smaller than the other of the electrodes. The first electrode and second electrode can be separated by a distance and electrically connected to a voltage source (4,5).

  1. Non thermal plasma surface cleaner and method of use

    KAUST Repository

    Neophytou, Marios; Lacoste, Deanna A.; Kirkus, Mindaugas

    2017-01-01

    Described herein are plasma generation devices and methods of use of the devices. The devices can be used for the cleaning of various surfaces and/or for inhibiting or preventing the accumulation of particulates, such as dust, or moisture on various surfaces. The devices can be used to remove dust and other particulate contaminants from solar panels and windows, or to avoid or minimize condensation on various surfaces. In an embodiment a plasma generation device is provided. The plasma generation device can comprise: a pair of electrodes (1,2) positioned in association with a surface of a dielectric substrate (3). The pair of electrodes (1,2) can comprise a first electrode (1) and a second electrode (2). The first electrode and second electrode can be of different sizes, one of the electrodes being smaller than the other of the electrodes. The first electrode and second electrode can be separated by a distance and electrically connected to a voltage source (4,5).

  2. Thermal shock fracture of graphite armor plate under the heat load of plasma disruption

    International Nuclear Information System (INIS)

    Horie, Tomoyoshi; Seki, Masahiro; Ohmori, Junji

    1989-01-01

    Experiments on the thermal shock brittle fracture of graphite plates were performed. Thermal loading which simulated a plasma disruption was produced by an electron beam facility. Pre-cracks produced on the surface propagated to the inside of the specimen even if the thermal stress on the surface was compressive. Two mechanisms are possible to produce tensile stress around the crack tip under thermal shock conditions. Temperature, thermal stress, and the stress intensity factor for the specimen were analyzed based on the finite element method for various heating conditions. The trend of experimental results under the asymmetric heating agrees qualitatively with the analytical results. This phenomenon is important for the design of plasma facing components made of graphite. Establishment of a lifetime prediction procedure including fatigue, fatigue crack growth, and brittle fracture is needed for graphite armors. (orig.)

  3. Velocity and texture of a plasma jet created in a plasma torch with fixed minimal arc length

    International Nuclear Information System (INIS)

    Vilotijevic, M; Dacic, B; Bozic, D

    2009-01-01

    A new plasma jet (PJ-100) plasma spraying torch with a fixed minimal arc length was tested and the basic working parameters were measured and evaluated. The velocity of the plasma exiting both the cylindrical and the conical anode nozzles was assessed by measuring the thrust generated by the plasma jet and by photographing the translation of plasma clouds (parts with different brightnesses) in the last third of the length of the plasma plume. The basic characteristics of the argon/hydrogen plasma jets (enthalpy, mean temperature, mean plasma velocity and effective exhaust thrust velocity) were determined for different working regimes, for both the cylindrical and the conical nozzles. The thermal efficiency of the new plasma torch is between 70% and 74% for the plasma generation power up to 90 kW. The plasma plume generated in the cylindrical nozzle has a homogeneous radial temperature (and velocity) distribution with a full laminar flow.

  4. Surface modification of biphasic calcium phosphate scaffolds by non-thermal atmospheric pressure nitrogen and air plasma treatment for improving osteoblast attachment and proliferation

    International Nuclear Information System (INIS)

    Choi, Yu-Ri; Kwon, Jae-Sung; Song, Doo-Hoon; Choi, Eun Ha; Lee, Yong-Keun; Kim, Kyoung-Nam; Kim, Kwang-Mahn

    2013-01-01

    Surface modifications induced by non-thermal plasma have been used extensively in biomedical applications. The attachment and proliferation of osteoblast cells are important in bone tissue engineering using scaffolds. Hence the effect of non-thermal plasma on hydroxyapatite/β-tri-calcium phosphate (HA/β-TCP) scaffolds in terms of improving osteoblast attachment and proliferation was investigated. Experimental groups were treated with non-thermal plasma for 10 min and 20 min and a control group was not treated with non-thermal plasma. For surface chemistry analysis, X-ray photoelectron spectroscopy (XPS) analysis was carried out. The hydrophilicity was determined from contact angle measurement on the surface. Atomic force microscopy analysis (AFM) was used to test the change in surface roughness and cell attachment and proliferation were evaluated using MC3T3-E1 osteoblast cells. XPS spectra revealed a decreased amount of carbon on the surface of the plasma-treated sample. The contact angle was also decreased following plasma treatment, indicating improved hydrophilicity of plasma-treated surfaces compared to the untreated disc. A significant increase in MC3T3E-1 cell attachment and proliferation was noted on plasma-treated samples as compared to untreated specimens. The results suggest that non-thermal atmospheric pressure nitrogen and air plasma treatments provide beneficial surface characteristics on HA/β-TCP scaffolds. - Highlights: ► Non-thermal plasma increased OH- and decreased C on biphasic scaffold. ► Non-thermal plasma had no effect on surface roughness. ► Non-thermal plasma resulted in hydrophilic surface. ► Non-thermal plasma resulted in better cell attachment and proliferation. ► Non-thermal plasma treatment on biphasic scaffold is useful for tissue engineering

  5. Power supply for plasma generator of HL-1M neutral beam injector

    International Nuclear Information System (INIS)

    Wang Detai; Qian Jiamei; Lei Guangjiu; Shun Mengda; Jiang Shaofeng; Wang Enyao; Lu Xuejun; Yang Tiehai; Wang Xuehua; Zhao Zhimin; Hao Ming; Huang Jianrong; Yu Yanqiu; Cheng Baoqiang; Wu Zhige; Sheng Ning; Hu Qingtao

    1999-01-01

    The diagram of the HL-1M Neutral Beam Injector (NBI) and the power supply (PS) system is shown. The NBI consists of ion source, beam line and power supply system etc. The ion source includes plasma generator and three-electrode extraction system. The power supply for plasma generator consists of a filament PS, an arc PS and gas valve PS. Testing has shown that the PS for plasma generator of the HL-1M NBI has excellent stability and obtain good plasma heating effect

  6. Operational characteristics of the high flux plasma generator magnum-PSI

    NARCIS (Netherlands)

    Van Eck, H.J.N.; Abrams, T.; Van Den Berg, M.A.; Brons, S.D.N.; Van Eden, G.G.; Jaworski, M.A.; Kaita, R.; Van Der Meiden, H.J.; Morgan, T.W.; van de Pol, Marc J.; Scholten, J.; Smeets, P.H.M.; De Temmerman, G.; De Vries, P.C.; Zeijlmans Van Emmichoven, P.A.

    2014-01-01

    In Magnum-PSI (MAgnetized plasma Generator and NUMerical modeling for Plasma Surface Interactions), the high density, low temperature plasma of a wall stabilized dc cascaded arc is confined to a magnetized plasma beam by a quasi-steady state axial magnetic field up to 1.3 T. It aims at conditions

  7. Enhanced active aluminum content and thermal behaviour of nano-aluminum particles passivated during synthesis using thermal plasma route

    International Nuclear Information System (INIS)

    Mathe, Vikas L.; Varma, Vijay; Raut, Suyog; Nandi, Amiya Kumar; Pant, Arti; Prasanth, Hima; Pandey, R.K.; Bhoraskar, Sudha V.; Das, Asoka K.

    2016-01-01

    Graphical abstract: - Highlights: • Synthesis of nano crystalline Al (nAl) using DC thermal plasma reactor. • In situ passivation of nAl by palmitic acid and air. • Enhanced active aluminum content obtained for palmitic acid passivated nAl. • Palmitic acid passivated nAl are quite stable in humid atmospheres. - Abstract: Here, we report synthesis and in situ passivation of aluminum nanoparticles using thermal plasma reactor. Both air and palmitc acid passivation was carried out during the synthesis in the thermal plasma reactor. The passivated nanoparticles have been characterized for their structural and morphological properties using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. In order to understand nature of passivation vibrational spectroscopic analysis have been carried out. The enhancement in active aluminum content and shelf life for a palmitic acid passivated nano-aluminum particles in comparison to the air passivated samples and commercially available nano Al powder (ALEX) has been observed. Thermo-gravimetric analysis was used to estimate active aluminum content of all the samples under investigation. In addition cerimetric back titration method was also used to estimate AAC and the shelf life of passivated aluminum particles. Structural, microstructural and thermogravomateric analysis of four year aged passivated sample also depicts effectiveness of palmitic acid passivation.

  8. Enhanced active aluminum content and thermal behaviour of nano-aluminum particles passivated during synthesis using thermal plasma route

    Energy Technology Data Exchange (ETDEWEB)

    Mathe, Vikas L., E-mail: vlmathe@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune 411007, Maharashtra (India); Varma, Vijay; Raut, Suyog [Department of Physics, Savitribai Phule Pune University, Pune 411007, Maharashtra (India); Nandi, Amiya Kumar; Pant, Arti; Prasanth, Hima; Pandey, R.K. [High Energy Materials Research Lab, Sutarwadi, Pune 411021, Maharashtra (India); Bhoraskar, Sudha V. [Department of Physics, Savitribai Phule Pune University, Pune 411007, Maharashtra (India); Das, Asoka K. [Utkal University, VaniVihar, Bhubaneswar, Odisha 751004 (India)

    2016-04-15

    Graphical abstract: - Highlights: • Synthesis of nano crystalline Al (nAl) using DC thermal plasma reactor. • In situ passivation of nAl by palmitic acid and air. • Enhanced active aluminum content obtained for palmitic acid passivated nAl. • Palmitic acid passivated nAl are quite stable in humid atmospheres. - Abstract: Here, we report synthesis and in situ passivation of aluminum nanoparticles using thermal plasma reactor. Both air and palmitc acid passivation was carried out during the synthesis in the thermal plasma reactor. The passivated nanoparticles have been characterized for their structural and morphological properties using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. In order to understand nature of passivation vibrational spectroscopic analysis have been carried out. The enhancement in active aluminum content and shelf life for a palmitic acid passivated nano-aluminum particles in comparison to the air passivated samples and commercially available nano Al powder (ALEX) has been observed. Thermo-gravimetric analysis was used to estimate active aluminum content of all the samples under investigation. In addition cerimetric back titration method was also used to estimate AAC and the shelf life of passivated aluminum particles. Structural, microstructural and thermogravomateric analysis of four year aged passivated sample also depicts effectiveness of palmitic acid passivation.

  9. Opacity measurements in shock-generated argon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D.

    1993-07-01

    Dense plasmas having uniform and constant density and temperature are generated by passage of a planar shock wave through gas. The opacity of the plasma is accurately measured versus wavelength by recording the risetime of emitted light. This technique is applicable to a wide variety of species and plasma conditions. Initial experiments in argon have produced plasmas with 2 eV temperatures, 0.004--0.04 g/cm{sup 3} densities, and coupling parameters {Gamma} {approximately}0.3--0.7. Measurements in visible light are compared with calculations using the HOPE code. An interesting peak in the capacity at 400 nm is observed for the first time and is identified with the 4s-5p transition in excited neutral argon atoms.

  10. A new concept Tandem thermal dissociator/electron impact ion source for RIB generation

    International Nuclear Information System (INIS)

    Alton, G.D.; Williams, C.

    1995-01-01

    An innovative thermal dissociation/electron impact ionization positive ion source is presently under design at the Oak Ridge National Laboratory for potential use for generating RIBs at the Holifield Radioactive Ion Beam Facility (HRIBF). Because of the low probability of simultaneously dissociating and efficiently ionizing the individual atomic constituents with conventional, hot-cathode, electron-impact ion sources, the ion beams extracted from these sources often appear as a mixture of several molecular sideband beams. In this way, the intensity of the species of interest is diluted. We have conceived an Ion source that combines the excellent molecular dissociation properties of a thermal dissociator and the high efficiency characteristics of an electron impact ionization source. If the concept proves to be a viable option, the source will be used as a complement to the electron beam plasma ion sources already in use at the HRIBF. The design features and principles of operation of the source are described in this article

  11. Generation of low-temperature air plasma for food processing

    Science.gov (United States)

    Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya

    2015-11-01

    The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

  12. Development of the ultra high efficiency thermal power generation facility

    Energy Technology Data Exchange (ETDEWEB)

    Sano, Toshihiro

    2010-09-15

    In order to prevent global warming, attention is focused on nuclear power generation and renewable energy such as wind and solar power generation. The electric power suppliers of Japan are aiming to increase the amount of nuclear and non-fossil fuel power generation over 50% of the total power generation by 2020. But this means that the remaining half will still be of thermal power generation using fossil fuel and will still play an important role. Under such circumstances, further efficiency improvement of the thermal power generation and its aggressive implementation is ongoing in Japan.

  13. Thermal plasma spheroidization and spray deposition of barium titanate powder and characterization of the plasma sprayable powder

    Energy Technology Data Exchange (ETDEWEB)

    Pakseresht, A.H., E-mail: amirh_pak@yahoo.com [Department of Ceramics, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of); Rahimipour, M.R. [Department of Ceramics, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of); Vaezi, M.R. [Department of Nanotechnology and Advanced Materials, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of); Salehi, M. [Department of Materials Engineering, Isfahan University of Technology, P.O. Box 84156-83111, Isfahan (Iran, Islamic Republic of)

    2016-04-15

    In this paper, atmospheric plasma spray method was used to produce dense plasma sprayable powder and thick barium titanate film. In this regard, the commercially feedstock powders were granulated and spheroidized by the organic binder and the thermal spray process, respectively. Scanning electron microscopy was used to investigate the microstructure of the produced powders and the final deposits. X-ray diffraction was also implemented to characterize phase of the sprayed powder. The results indicated that spheroidized powder had suitable flowability as well as high density. The micro-hardness of the film produced by the sprayed powders was higher than that of the film deposited by the irregular granules. Additionally, relative permittivity of the films was increased by decreasing the defects from 160 to 293 for film deposited using spheroidized powder. The reduction in the relative permittivity of deposits, in comparison with the bulk material, was due to the existence of common defects in the thermal spray process. - Highlights: • We prepare sprayable BaTiO{sub 3} powder with no or less inside voids for plasma spray application for first time. • The sprayable powder has good flow characteristics and high density. • Powder spheroidization via plasma spray improves the hardness and dielectric properties of the deposited film.

  14. Thermal plasma spheroidization and spray deposition of barium titanate powder and characterization of the plasma sprayable powder

    International Nuclear Information System (INIS)

    Pakseresht, A.H.; Rahimipour, M.R.; Vaezi, M.R.; Salehi, M.

    2016-01-01

    In this paper, atmospheric plasma spray method was used to produce dense plasma sprayable powder and thick barium titanate film. In this regard, the commercially feedstock powders were granulated and spheroidized by the organic binder and the thermal spray process, respectively. Scanning electron microscopy was used to investigate the microstructure of the produced powders and the final deposits. X-ray diffraction was also implemented to characterize phase of the sprayed powder. The results indicated that spheroidized powder had suitable flowability as well as high density. The micro-hardness of the film produced by the sprayed powders was higher than that of the film deposited by the irregular granules. Additionally, relative permittivity of the films was increased by decreasing the defects from 160 to 293 for film deposited using spheroidized powder. The reduction in the relative permittivity of deposits, in comparison with the bulk material, was due to the existence of common defects in the thermal spray process. - Highlights: • We prepare sprayable BaTiO_3 powder with no or less inside voids for plasma spray application for first time. • The sprayable powder has good flow characteristics and high density. • Powder spheroidization via plasma spray improves the hardness and dielectric properties of the deposited film.

  15. Magnum-psi, a plasma generator for plasma-surface interaction research in ITER-like conditions

    International Nuclear Information System (INIS)

    Groot, B. de; Rooij, G.J. van; Veremiyenko, V.; Hellermann, M.G. von; Eck, H.J.N. van; Barth, C.J.; Kruijtzer, G.L.; Wolff, J.C.; Goedheer, W.J.; Lopes Cardozo, N.J.; Kleyn, A.W.; Smeets, P.H.M.; Brezinsek, S.; Pospieszczyk, A.; Engeln, R.A.H.; Dahiya, R.P.

    2005-01-01

    The FOM Institute for Plasma Physics is preparing the construction of the linear plasma generator, Magnum-psi. A pilot experiment (Pilot-psi) has been constructed, which we have used to optimize the cascaded arc plasma source and to explore the effect of high magnetic fields on the source operation as well as the expanding plasma beam and the effectiveness of Ohmic heating for manipulating the electron temperature and plasma density after the plasma expansion. Results are presented that demonstrate increasing source efficiency for increasing magnetic fields (up to 1.6 T). Thomson scattering measurements demonstrate that ITER relevant plasma fluxes are presently achieved in Pilot-psi: ∼10 24 m -2 s -1 and that additional heating could elevate the plasma temperature from 1.0 to 1.7 eV

  16. Engineering design of plasma generation devices using Elmer finite element simulation methods

    Directory of Open Access Journals (Sweden)

    Daniel Bondarenko

    2017-02-01

    Full Text Available Plasma generation devices are important technology for many engineering disciplines. The process for acquiring experience for designing plasma devices requires practice, time, and the right tools. The practice and time depend on the individual and the access to the right tools can be a limiting factor to achieve experience and to get an idea on the possible risks. The use of Elmer finite element method (FEM software for verifying plasma engineering design is presented as an accessible tool that can help modeling multi-physics and verifying plasma generation devices. Furthermore, Elmer FEM will be suitable for experienced engineer and can be used for determining the risks in a design or a process that use plasma. A physical experiment was conducted to demonstrate new features of plasma generation technology where results are compared with plasma simulation using Elmer FEM.

  17. The influence of plasma motion on disruption generated runaway electrons

    International Nuclear Information System (INIS)

    Russo, A.J.

    1991-01-01

    One of the possible consequences of disruptions is the generation of runaway electrons which can impact plasma facing components and cause damage due to high local energy deposition. This problem becomes more serious as the machine size and plasma current increases. Since large size and high currents are characteristics of proposed future machines, control of runaway generation is an important design consideration. A lumped circuit model for disruption runaway electron generation indicates that control circuitry on strongly influence runaway behavior. A comparison of disruption data from several shots on JET and D3-D with model results, demonstrate the effects of plasma motion on runaway number density and energy. 6 refs., 12 figs

  18. Propagation of sound and thermal waves in an ionizing-recombining hydrogen plasma: Revision of results

    International Nuclear Information System (INIS)

    Di Sigalotti, Leonardo G.; Sira, Eloy; Tremola, Ciro

    2002-01-01

    The propagation of acoustic and thermal waves in a heat conducting, hydrogen plasma, in which photoionization and photorecombination [H + +e - H+hν(χ)] processes are progressing, is re-examined here using linear analysis. The resulting dispersion equation is solved analytically and the results are compared with previous solutions for the same plasma model. In particular, it is found that wave propagation in a slightly and highly ionized hydrogen plasma is affected by crossing between acoustic and thermal modes. At temperatures where the plasma is partially ionized, waves of all frequencies propagate without the occurrence of mode crossing. These results disagree with those reported in previous work, thereby leading to a different physical interpretation of the propagation of small linear disturbances in a conducting, ionizing-recombining, hydrogen plasma

  19. Thermal de-isolation of silicon microstructures in a plasma etching environment

    International Nuclear Information System (INIS)

    Lee, Yong-Seok; Jang, Yun-Ho; Kim, Yong-Kweon; Kim, Jung-Mu

    2013-01-01

    This paper presents a theoretical and experimental strategy for thermal de-isolation of silicon microstructures during a plasma etching process. Heat sinking blocks and thin metal layers are implemented around a thermally isolated mass to avoid severe spring width losses by a steep temperature rise. Thermal de-isolation significantly reduces the fabrication errors from −51.0% to −9.0% and from −39.5% to −6.7% for spring widths and resonant frequencies, respectively. Thermal de-isolation also reduces the standard deviation of resonant frequencies from 8.7% to 1.5% across a wafer, which clearly demonstrates the proposed method. (paper)

  20. Incineration/vitrification of radioactive wastes and combustion of pyrolysis gases in thermal plasmas

    International Nuclear Information System (INIS)

    Girold, Ch.

    1997-03-01

    Two thermal plasma processes used for incineration of radioactive technological wastes (cellulose, plastics, rubber...) have been investigated. First, the different types of radioactive wastes are presented, with a special attention to those which may benefit from a high temperature thermal treatment. The most significant thermal plasma processes, suitable for this goal, are described. Then, the author deals with the post-combustion, in an oxygen plasma jet reactor, of gases from burnable radioactive waste pyrolysis. An experimental planning method as been used to evaluate the combustion performances in the reactor, with a wide range of gas composition and running parameters such as oxygen excess and electrical power. The results of a modeling of kinetics, based on 116 chemicals reactions between 25 species, are compared with experimental values. Finally, an oxygen plasma reactor where the arc is transferred on a basalt melt is experimented. The efficiency of the combustion and the homogeneity of the glass are discussed. The volatility of some glass elements and tracers added to the wastes is also approached in two different ways: by post-trial material balance and by an optical emission spectroscopic method. The author built a diagnostic method that allows the following versus time of the metallic vapours above the melt. (author)

  1. Transport of thermal plasma above the auroral ionosphere in the presence of electrostatic ion-cyclotron turbulence

    Directory of Open Access Journals (Sweden)

    V. E. Zakharov

    Full Text Available The electron component of intensive electric currents flowing along the geomagnetic field lines excites turbulence in the thermal magnetospheric plasma. The protons are then scattered by the excited electromagnetic waves, and as a result the plasma is stable. As the electron and ion temperatures of the background plasma are approximately equal each other, here electrostatic ion-cyclotron (EIC turbulence is considered. In the nonisothermal plasma the ion-acoustic turbulence may occur additionally. The anomalous resistivity of the plasma causes large-scale differences of the electrostatic potential along the magnetic field lines. The presence of these differences provides heating and acceleration of the thermal and energetic auroral plasma. The investigation of the energy and momentum balance of the plasma and waves in the turbulent region is performed numerically, taking the magnetospheric convection and thermal conductivity of the plasma into account. As shown for the quasi-steady state, EIC turbulence may provide differences of the electric potential of ΔV≈1–10 kV at altitudes of 500 < h < 10 000 km above the Earth's surface. In the turbulent region, the temperatures of the electrons and protons increase only a few times in comparison with the background values.

    Key words. Magnetospheric physics (electric fields; plasma waves and instabilities

     

  2. Plasma technology for treatment of waste

    Energy Technology Data Exchange (ETDEWEB)

    Cohn, D [Massachusetts Inst. of Technology, Cambridge, MA (United States). Plasma Fusion Center

    1997-12-31

    Meeting goals for waste cleanup will require new technology with improved environmental attractiveness and reduced cost. Plasma technology appears promising because of the high degree of controllability; capability to process waste without the adverse effects of combustion; and a very wide temperature range of operation. At the Plasma Fusion Center at the Massachusetts Institute of Technology, a range of plasma technologies are being investigated. `Hot` thermal plasmas produced by DC arc technology are being examined for treatment of solid waste. In conjunction with this activity, new diagnostics are being developed for monitoring arc furnace operating parameters and gaseous emissions. Electron-beam generated plasma technology is being investigated as a means of producing non-thermal `cold` plasmas for selective processing of dilute concentrations of gaseous waste. (author). 4 figs., 5 refs.

  3. Experimental investigation of thermal conduction and related phenomena in a laser heated plasma

    International Nuclear Information System (INIS)

    Gray, D.R.

    1979-02-01

    Thermal conduction in plasmas is of major importance especially in controlled nuclear fusion studies. Direct measurements are rare. When the temperature gradient in a plasma becomes large enough classical thermal conduction (Heat flux q = -kΔT) no longer applies and it is thought that q is limited to some fraction of the free streaming limit qsub(m). The main experiment is the heating of a z-pinch plasma by a fast rising, intense carbon dioxide laser pulse. Electron temperature and density in time and space are diagnosed by ruby laser scattering. The profiles obtained were consistent with a flux limited to approximately 3% of the free streaming limit. Ion acoustic turbulence is observed along the temperature gradient. It is shown that the observed turbulence level is consistent with the heat flux limitation. At electron densities > 10 17 cm -3 backscattered light is observed from the plasma whose growth rate implies that it is Brillouin scattered. (author)

  4. Optimized functionally graded La2Zr2O7/8YSZ thermal barrier coatings fabricated by suspension plasma spraying

    International Nuclear Information System (INIS)

    Wang, Chaohui; Wang, You; Fan, Shan; You, Yuan; Wang, Liang; Yang, Changlong; Sun, Xiaoguang; Li, Xuewei

    2015-01-01

    In this paper, an optimized functionally graded coating (OFGC) was successfully fabricated by suspension plasma spraying (SPS) with feedstocks of the suspension of nanoparticles. La 2 Zr 2 O 7 /8YSZ OFGC with gradual compositional variation along the through-thickness direction is proposed to mitigate spallation and crack formation owing to the high residual stresses caused by frequent thermal cycling for TBCs. The single ceramic layer coatings (SCLC) of LZ and double ceramic layer coatings (DCLC) of LZ/8YSZ were fabricated by SPS as comparison. The phase composition and microstructure of the SCLC, OFGC and DCLC were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS). Moreover, the thermal cycling tests were carried out to evaluate their thermal shock behavior. Changes in weight and morphology of specimens were analyzed during thermal cycling tests. The results showed that OFGC has extended lifetime compared with SCLC and DCLC. The failure of DCLC with clear interface between different ceramic layers occurred via delamination mode, as a result of crack initiation and propagation generated by thermal mismatch between LZ and 8YSZ. While the failure of OFGC occurred in thermally grown oxide (TGO) layers, indicating that the gradual compositional variation avoided thermal stress concentration in the top ceramic layers. - Highlights: • Optimized functionally graded coatings and double ceramic layer coatings were deposited by suspension plasma spray. • The graded area of OFGC is continuously changed from inner 8YSZ to outer La 2 Zr 2 O 7 (LZ). • The OFGC shows a more extended thermal cycling life than the LZ SCLC and LZ/8YSZ DCLC. • Various failure mechanisms were proposed to explain thermal cycling behavior

  5. Studies of thermal energy confinement scaling in PDX plasmas: D0 → H+ limiter discharges

    International Nuclear Information System (INIS)

    Kaye, S.M.; Goldston, R.J.; Bell, M.

    1984-06-01

    Experiments were performed on the PDX tokamak to study plasma heating and β scaling with higher power, near-perpendicular neutral beam injection. The data taken during these experiments were analyzed using a time-dependent data interpretation code (TRANSP) to study the transport and thermal confinement scaling over a wide range of plasma parameters. This study focuses on results from experiments with D 0 injection into H + plasmas using graphite rail limiters, a = 40 to 44 cm, R = 143 cm, I/sub p/ = 200 to 480 kA, B/sub T/ = 0.7 to 2.2 T, and typically anti n/sub e/ = 2.5 to 4.2 x 10 13 cm -3 . The results of this study indicate that for both ohmic and neutral beam heated discharges the energy flow out of the plasma is dominated by anomalous electron losses, attributed to electron thermal conduction. The ion conduction losses are well described to electron thermal conduction. The ion conduction losses are well described by neoclassical theory; however, the total ion loss influences the power balance significantly only at high toroidal fields and high plasma currents

  6. Preparation of boron-rich aluminum boride nanoparticles by RF thermal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sooseok [Inha University, Department of Chemical Engineering and Regional Innovation Center for Environmental Technology of Thermal Plasma (Korea, Republic of); Matsuo, Jiro; Cheng, Yingying [Tokyo Institute of Technology, Department of Environmental Chemistry and Engineering (Japan); Watanabe, Takayuki, E-mail: watanabe@chemenv.titech.ac.jp [Kyushu University, Department of Chemical Engineering (Japan)

    2013-08-15

    Boron-rich compounds of AlB{sub 12} and AlB{sub 10} nanoparticles were synthesized by a radiofrequency thermal plasma. Aluminum and boron raw powders were evaporated in virtue of high enthalpy of the thermal plasma in upstream region, followed by the formation of aluminum boride nanoparticles in the tail region of plasma flame with rapid quenching. A high production rate of aluminum boride was confirmed by the X-ray diffraction measurement in the case of high input power, high boron content in raw material and helium inner gas. Polyhedral nanoparticles of 20.8 nm in mean size were observed by a transmission electron microscope. In the raw powder mixture of aluminum, titanium, and boron, titanium-boride nanoparticles were synthesized preferentially, because the Gibbs free energy for the boridation of titanium is lower than that of aluminum. Since the nucleation temperature of boron is higher than that of aluminum, the condensation of metal monomers onto boron nuclei results in the formation of boron-rich aluminum boride nanoparticles.

  7. Generation of zonal flows in rotating fluids and magnetized plasmas

    DEFF Research Database (Denmark)

    Juul Rasmussen, J.; Garcia, O.E.; Naulin, V.

    2006-01-01

    The spontaneous generation of large-scale flows by the rectification of small-scale turbulent fluctuations is of great importance both in geophysical flows and in magnetically confined plasmas. These flows regulate the turbulence and may set up effective transport barriers. In the present....... The analogy to large-scale flow generation in drift-wave turbulence dynamics in magnetized plasma is briefly discussed....

  8. Hologaphy of a CO2 laser generated plasma

    International Nuclear Information System (INIS)

    Elkerbout, A.C.H.; Van Dijk, J.W.; Donaldson, T.P.

    1976-01-01

    An expermental technique for generating holographic interferograms is discussed and illustrated with results obtained on a plasma generated by a 75 J CO 2 laser pulse incident at intensities of approximately 9 x 10 12 W/cm 2 on a plane carbon target. (author)

  9. A non-equilibrium simulation of thermal constriction in a cascaded arc hydrogen plasma

    International Nuclear Information System (INIS)

    Peerenboom, K S C; Goedheer, W J; Van Dijk, J; Kroesen, G M W

    2014-01-01

    The cascaded arc hydrogen plasma of Pilot-PSI is studied in a non-LTE model. We demonstrate that the effect of vibrationally excited molecules on the heavy-particle-assisted dissociation is crucial for obtaining thermal constriction. To the best of our knowledge, thermal constriction has not been obtained before in a non-LTE simulation. Probably, realistic numerical studies of this type of plasma were hindered by numerical problems, preventing the non-LTE simulations to show characteristic physical mechanisms such as thermal constriction. In this paper we show that with the help of appropriate numerical strategies thermal constriction can be obtained in a non-LTE simulation. To this end, a new source term linearization technique is developed, which ensures physical solutions even near chemical equilibrium where the composition is dominated by chemical source terms. Results of the model are compared with experiments on Pilot-PSI and show good agreement with pressure and voltage measurements in the source. (paper)

  10. MAGNUM-PSI, a plasma generator for plasma-surface interaction research in ITER-like conditions

    International Nuclear Information System (INIS)

    Goedheer, W.J.; Rooij, G.J. van; Veremiyenko, V.; Ahmad, Z.; Barth, C.J.; Eck, H.J.N. van; Groot, B. de; Hellermann, M.G. von; Kruijtzer, G.L.; Wolff, J.C.; Brezinsek, S.; Philipps, V.; Pospieszczyk, A.; Samm, U.; Schweer, B.; Dahiya, R.P.; Engeln, R.A.H.; Schram, D.C.; Fantz, U.; Kleyn, A.W.; Lopes Cardozo, N.J.

    2005-01-01

    The FOM-Institute for Plasma Physics - together with its TEC partners - is preparing the construction of Magnum-psi, a magnetized (3 T), steady-state, large area (100 cm 2 ), high-flux (up to 10 24 H + ions m -2 s -1 ) plasma generator. The research programme of Magnum-psi will address the questions for the ITER divertor: erosion, redeposition and hydrogen retention with carbon substrates, melting of metal surfaces, erosion and redeposition with mixed materials. In order to explore and develop the techniques to be applied in Magnum-psi, a pilot experiment (Pilot-psi), operating at a magnetic field up to 1.6 Tesla, has been constructed. Pilot-psi produces a hydrogen plasma beam with the required parameters (T e ≤ 1eV and flux ≥ 10 23 m -2 s -1 ) over an area of 1 cm 2 . In this paper the results of extensive diagnostic measurements on Pilot-psi (a.o., Thomson Scattering and high-resolution spectroscopy), combined with numerical studies of the source and the expansion of the plasma will be presented to demonstrate the feasibility of the large Magnum-psi plasma generator. (author)

  11. Optimal control theory applied to fusion plasma thermal stabilization

    International Nuclear Information System (INIS)

    Sager, G.; Miley, G.; Maya, I.

    1985-01-01

    Many authors have investigated stability characteristics and performance of various burn control schemes. The work presented here represents the first application of optimal control theory to the problem of fusion plasma thermal stabilization. The objectives of this initial investigation were to develop analysis methods, demonstrate tractability, and present some preliminary results of optimal control theory in burn control research

  12. Production of coloured glass-ceramics from incinerator ash using thermal plasma technology.

    Science.gov (United States)

    Cheng, T W; Huang, M Z; Tzeng, C C; Cheng, K B; Ueng, T H

    2007-08-01

    Incineration is a major treatment process for municipal solid waste in Taiwan. It is estimated that over 1.5 Mt of incinerator ash are produced annually. This study proposes using thermal plasma technology to treat incinerator ash. Sintered glass-ceramics were produced using quenched vitrified slag with colouring agents added. The experimental results showed that the major crystalline phases developed in the sintered glass-ceramics were gehlenite and wollastonite, but many other secondary phases also appeared depending on the colouring agents added. The physical/mechanical properties, chemical resistance and toxicity characteristic leaching procedure of the coloured glass-ceramics were satisfactory. The glass-ceramic products obtained from incinerator ash treated with thermal plasma technology have great potential for building applications.

  13. Effects of plasma jet parameters, ionization, thermal conduction, and radiation on stagnation conditions of an imploding plasma liner

    Science.gov (United States)

    Stanic, Milos

    The disciplines of High Energy Density Physics (HEDP) and Inertial Confinement Fusion (ICF) are characterized by hypervelocity implosions and strong shocks. The Plasma Liner Experiment (PLX) is focused on reaching HEDP and/or ICF relevant regimes in excess of 1 Mbar peak pressure by the merging and implosion of discrete plasma jets, as a potentially efficient path towards these extreme conditions in a laboratory. In this work we have presented the first 3D simulations of plasma liner, formation, and implosion by the merging of discrete plasma jets in which ionization, thermal conduction, and radiation are all included in the physics model. The study was conducted by utilizing a smoothed particle hydrodynamics code (SPHC) and was a part of the plasma liner experiment (PLX). The salient physics processes of liner formation and implosion are studied, namely vacuum propagation of plasma jets, merging of the jets (liner forming), implosion (liner collapsing), stagnation (peak pressure), and expansion (rarefaction wave disassembling the target). Radiative transport was found to significantly reduce the temperature of the liner during implosion, thus reducing the thermal expansion rates and leaving more pronounced gradients in the plasma liner during the implosion compared with ideal hydrodynamic simulations. These pronounced gradients lead to a greater sensitivity of initial jet geometry and symmetry on peak pressures obtained. Accounting for ionization and transport, many cases gave higher peak pressures than the ideal hydrodynamic simulations. Scaling laws were developed accordingly, creating a non-dimensional parameter space in which performance of an imploding plasma jet liner can be estimated. It is shown that HEDP regimes could be reached with ≈ 5 MJ of liner energy, which would translate to roughly 10 to 20 MJ of stored (capacitor) energy. This is a potentially significant improvement over the currently available means via ICF of achieving HEDP and nuclear

  14. Determination of Plasma Screening Effects for Thermonuclear Reactions in Laser-generated Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yuanbin; Pálffy, Adriana, E-mail: yuanbin.wu@mpi-hd.mpg.de, E-mail: Palffy@mpi-hd.mpg.de [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

    2017-03-20

    Due to screening effects, nuclear reactions in astrophysical plasmas may behave differently than in the laboratory. The possibility to determine the magnitude of these screening effects in colliding laser-generated plasmas is investigated theoretically, having as a starting point a proposed experimental setup with two laser beams at the Extreme Light Infrastructure facility. A laser pulse interacting with a solid target produces a plasma through the Target Normal Sheath Acceleration scheme, and this rapidly streaming plasma (ion flow) impacts a secondary plasma created by the interaction of a second laser pulse on a gas jet target. We model this scenario here and calculate the reaction events for the astrophysically relevant reaction {sup 13}C({sup 4}He, n ){sup 16}O. We find that it should be experimentally possible to determine the plasma screening enhancement factor for fusion reactions by detecting the difference in reaction events between two scenarios of ion flow interacting with the plasma target and a simple gas target. This provides a way to evaluate nuclear reaction cross-sections in stellar environments and can significantly advance the field of nuclear astrophysics.

  15. Relativistic self-focusing of intense laser beam in thermal collisionless quantum plasma with ramped density profile

    Directory of Open Access Journals (Sweden)

    S. Zare

    2015-04-01

    Full Text Available Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum plasma with considering a ramped density profile. In this density profile due to the increase in the plasma density, an earlier and stronger self-focusing effect is noticed where the beam width oscillates with higher frequency and less amplitude. Moreover, the effect of the density profile slope and the initial plasma density on the laser propagation has been studied. It is found that, by increasing the initial density and the ramp slope, the laser beam focuses faster with less oscillation amplitude, smaller laser spot size and more oscillations. Furthermore, a comparison is made among the laser self-focusing in thermal quantum plasma, cold quantum plasma and classical plasma. It is realized that the laser self-focusing in the quantum plasma becomes stronger in comparison with the classical regime.

  16. Treatment of mixed wastes by thermal plasma discharges; Tratamiento de desechos mixtos por descargas de plasma termico

    Energy Technology Data Exchange (ETDEWEB)

    Diaz A, L.V.; Pacheco S, J.O.; Pacheco P, M.; Monroy G, F.; Emeterio H, M. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: lauradiazarch@yahoo.com.mx

    2007-07-01

    The National Institute of Nuclear Research (ININ) uses an ion exchange resin: IRN 150 (copolymer styrene Divynilbencene) in the TRIGA Mark III reactor to absorb polluted particles with heavy metals and radioactive particles of low level. Once the capacity of filtrate of the resin is exceeded, it is replaced and considered with a mixed waste. This work is based on taking advantage of the advantages of the technique of the thermal plasma in a unique process: (high energy density 105W/cm{sup 3} high enthalpy, high reactivity chemical, high operation temperatures 6000-11500K and quick quenching 106K/s) for the degradation and vitrification of the resin IRN 150. The reactor of plasma is compact and it works to atmospheric pressure and reduced thermal inertia. Therefore, the main parameters involved during the degradation tests and vitrification are: plasma current, voltage, gas flow and distance among the electrodes. The used vitreous matrix, is obtained from a ceramic clay composed by an oxides mixture which are characterized by their good resistance to mechanical impacts and erosion caused by the water. The ceramic clay and the resin IRN 150 were analyzed before the treatment by Scanning Electron Microscopy (MEB), X-ray Diffraction (DRX), Thermal gravimetry (TGA) once vitrified the materials were also analyzed by MEB and DRX. It is obtained as a result that the material more appropriate to be used as vitreous matrix it is a ceramic clay formed by several oxides, being operated the plasma system with a current of 115A, voltage of 25V, flow of the argon gas of 5 l/m and a distance among electrodes of 10mm. With the development of the proposed technology and the material for the vitreous matrix, be rotted to try in a future a great variety of mixed waste. (Author)

  17. Temperature of thermal plasma jets: A time resolved approach

    Energy Technology Data Exchange (ETDEWEB)

    Sahasrabudhe, S N; Joshi, N K; Barve, D N; Ghorui, S; Tiwari, N; Das, A K, E-mail: sns@barc.gov.i [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai - 400 094 (India)

    2010-02-01

    Boltzmann Plot method is routinely used for temperature measurement of thermal plasma jets emanating from plasma torches. Here, it is implicitly assumed that the plasma jet is 'steady' in time. However, most of the experimenters do not take into account the variations due to ripple in the high current DC power supplies used to run plasma torches. If a 3-phase transductor type of power supply is used, then the ripple frequency is 150 Hz and if 3- phase SCR based power supply is used, then the ripple frequency is 300 Hz. The electrical power fed to plasma torch varies at ripple frequency. In time scale, it is about 3.3 to 6.7 ms for one cycle of ripple and it is much larger than the arc root movement times which are within 0.2 ms. Fast photography of plasma jets shows that the luminosity of plasma jet also varies exactly like the ripple in the power supply voltage and thus with the power. Intensity of line radiations varies nonlinearly with the instantaneous power fed to the torch and the simple time average of line intensities taken for calculation of temperature is not appropriate. In this paper, these variations and their effect on temperature determination are discussed and a method to get appropriate data is suggested. With a small adaptation discussed here, this method can be used to get temperature profile of plasma jet within a short time.

  18. Observed and modelled effects of auroral precipitation on the thermal ionospheric plasma: comparing the MICA and Cascades2 sounding rocket events

    Science.gov (United States)

    Lynch, K. A.; Gayetsky, L.; Fernandes, P. A.; Zettergren, M. D.; Lessard, M.; Cohen, I. J.; Hampton, D. L.; Ahrns, J.; Hysell, D. L.; Powell, S.; Miceli, R. J.; Moen, J. I.; Bekkeng, T.

    2012-12-01

    Auroral precipitation can modify the ionospheric thermal plasma through a variety of processes. We examine and compare the events seen by two recent auroral sounding rockets carrying in situ thermal plasma instrumentation. The Cascades2 sounding rocket (March 2009, Poker Flat Research Range) traversed a pre-midnight poleward boundary intensification (PBI) event distinguished by a stationary Alfvenic curtain of field-aligned precipitation. The MICA sounding rocket (February 2012, Poker Flat Research Range) traveled through irregular precipitation following the passage of a strong westward-travelling surge. Previous modelling of the ionospheric effects of auroral precipitation used a one-dimensional model, TRANSCAR, which had a simplified treatment of electric fields and did not have the benefit of in situ thermal plasma data. This new study uses a new two-dimensional model which self-consistently calculates electric fields to explore both spatial and temporal effects, and compares to thermal plasma observations. A rigorous understanding of the ambient thermal plasma parameters and their effects on the local spacecraft sheath and charging, is required for quantitative interpretation of in situ thermal plasma observations. To complement this TRANSCAR analysis we therefore require a reliable means of interpreting in situ thermal plasma observation. This interpretation depends upon a rigorous plasma sheath model since the ambient ion energy is on the order of the spacecraft's sheath energy. A self-consistent PIC model is used to model the spacecraft sheath, and a test-particle approach then predicts the detector response for a given plasma environment. The model parameters are then modified until agreement is found with the in situ data. We find that for some situations, the thermal plasma parameters are strongly driven by the precipitation at the observation time. For other situations, the previous history of the precipitation at that position can have a stronger

  19. Pair plasma relaxation time scales.

    Science.gov (United States)

    Aksenov, A G; Ruffini, R; Vereshchagin, G V

    2010-04-01

    By numerically solving the relativistic Boltzmann equations, we compute the time scale for relaxation to thermal equilibrium for an optically thick electron-positron plasma with baryon loading. We focus on the time scales of electromagnetic interactions. The collisional integrals are obtained directly from the corresponding QED matrix elements. Thermalization time scales are computed for a wide range of values of both the total-energy density (over 10 orders of magnitude) and of the baryonic loading parameter (over 6 orders of magnitude). This also allows us to study such interesting limiting cases as the almost purely electron-positron plasma or electron-proton plasma as well as intermediate cases. These results appear to be important both for laboratory experiments aimed at generating optically thick pair plasmas as well as for astrophysical models in which electron-positron pair plasmas play a relevant role.

  20. Higher Temperature Thermal Barrier Coatings with the Combined Use of Yttrium Aluminum Garnet and the Solution Precursor Plasma Spray Process

    Science.gov (United States)

    Gell, Maurice; Wang, Jiwen; Kumar, Rishi; Roth, Jeffery; Jiang, Chen; Jordan, Eric H.

    2018-04-01

    Gas-turbine engines are widely used in transportation, energy and defense industries. The increasing demand for more efficient gas turbines requires higher turbine operating temperatures. For more than 40 years, yttria-stabilized zirconia (YSZ) has been the dominant thermal barrier coating (TBC) due to its outstanding material properties. However, the practical use of YSZ-based TBCs is limited to approximately 1200 °C. Developing new, higher temperature TBCs has proven challenging to satisfy the multiple property requirements of a durable TBC. In this study, an advanced TBC has been developed by using the solution precursor plasma spray (SPPS) process that generates unique engineered microstructures with the higher temperature yttrium aluminum garnet (YAG) to produce a TBC that can meet and exceed the major performance standards of state-of-the-art air plasma sprayed YSZ, including: phase stability, sintering resistance, CMAS resistance, thermal cycle durability, thermal conductivity and erosion resistance. The temperature improvement for hot section gas turbine materials (superalloys & TBCs) has been at the rate of about 50 °C per decade over the last 50 years. In contrast, SPPS YAG TBCs offer the near-term potential of a > 200 °C improvement in temperature capability.

  1. Higher Temperature Thermal Barrier Coatings with the Combined Use of Yttrium Aluminum Garnet and the Solution Precursor Plasma Spray Process

    Science.gov (United States)

    Gell, Maurice; Wang, Jiwen; Kumar, Rishi; Roth, Jeffery; Jiang, Chen; Jordan, Eric H.

    2018-02-01

    Gas-turbine engines are widely used in transportation, energy and defense industries. The increasing demand for more efficient gas turbines requires higher turbine operating temperatures. For more than 40 years, yttria-stabilized zirconia (YSZ) has been the dominant thermal barrier coating (TBC) due to its outstanding material properties. However, the practical use of YSZ-based TBCs is limited to approximately 1200 °C. Developing new, higher temperature TBCs has proven challenging to satisfy the multiple property requirements of a durable TBC. In this study, an advanced TBC has been developed by using the solution precursor plasma spray (SPPS) process that generates unique engineered microstructures with the higher temperature yttrium aluminum garnet (YAG) to produce a TBC that can meet and exceed the major performance standards of state-of-the-art air plasma sprayed YSZ, including: phase stability, sintering resistance, CMAS resistance, thermal cycle durability, thermal conductivity and erosion resistance. The temperature improvement for hot section gas turbine materials (superalloys & TBCs) has been at the rate of about 50 °C per decade over the last 50 years. In contrast, SPPS YAG TBCs offer the near-term potential of a > 200 °C improvement in temperature capability.

  2. A study of single and binary ion plasma expansion into laboratory-generated plasma wakes

    Science.gov (United States)

    Wright, Kenneth Herbert, Jr.

    1988-01-01

    Plasma expansion into the wake of a large rectangular plate immersed in a collisionless, supersonic plasma was investigated in laboratory experiments. The experimental conditions address both single ion and binary ion plasma flows for the case of a body whose size is large in comparison with the Debye length, when the potential difference between the body and the plasma is relatively small. A new plasma source was developed to generate equi-velocity, binary ion plasma flows, which allows access to new parameter space that have previously been unavailable for laboratory studies. Specifically, the new parameters are the ionic mass ratio and the ionic component density ratio. In a series of experiments, a krypton-neon plasma is employed where the ambient density ratio of neon to krypton is varied more than an order of magnitude. The expansion in both the single ion and binary ion plasma cases is limited to early times, i.e., a few ion plasma periods, by the combination of plasma density, plasma drift speed, and vacuum chamber size, which prevented detailed comparison with self-similar theory.

  3. Self-consistent modeling of radio-frequency plasma generation in stellarators

    Energy Technology Data Exchange (ETDEWEB)

    Moiseenko, V. E., E-mail: moiseenk@ipp.kharkov.ua; Stadnik, Yu. S., E-mail: stadnikys@kipt.kharkov.ua [National Academy of Sciences of Ukraine, National Science Center Kharkov Institute of Physics and Technology (Ukraine); Lysoivan, A. I., E-mail: a.lyssoivan@fz-juelich.de [Royal Military Academy, EURATOM-Belgian State Association, Laboratory for Plasma Physics (Belgium); Korovin, V. B. [National Academy of Sciences of Ukraine, National Science Center Kharkov Institute of Physics and Technology (Ukraine)

    2013-11-15

    A self-consistent model of radio-frequency (RF) plasma generation in stellarators in the ion cyclotron frequency range is described. The model includes equations for the particle and energy balance and boundary conditions for Maxwell’s equations. The equation of charged particle balance takes into account the influx of particles due to ionization and their loss via diffusion and convection. The equation of electron energy balance takes into account the RF heating power source, as well as energy losses due to the excitation and electron-impact ionization of gas atoms, energy exchange via Coulomb collisions, and plasma heat conduction. The deposited RF power is calculated by solving the boundary problem for Maxwell’s equations. When describing the dissipation of the energy of the RF field, collisional absorption and Landau damping are taken into account. At each time step, Maxwell’s equations are solved for the current profiles of the plasma density and plasma temperature. The calculations are performed for a cylindrical plasma. The plasma is assumed to be axisymmetric and homogeneous along the plasma column. The system of balance equations is solved using the Crank-Nicholson scheme. Maxwell’s equations are solved in a one-dimensional approximation by using the Fourier transformation along the azimuthal and longitudinal coordinates. Results of simulations of RF plasma generation in the Uragan-2M stellarator by using a frame antenna operating at frequencies lower than the ion cyclotron frequency are presented. The calculations show that the slow wave generated by the antenna is efficiently absorbed at the periphery of the plasma column, due to which only a small fraction of the input power reaches the confinement region. As a result, the temperature on the axis of the plasma column remains low, whereas at the periphery it is substantially higher. This leads to strong absorption of the RF field at the periphery via the Landau mechanism.

  4. AC/DC/pulsed-power modulator for corona-plasma generation

    NARCIS (Netherlands)

    Ariaans, T.H.P.; Pemen, A.J.M.; Winands, G.J.J.; Heesch, van E.J.M.; Liu, Z.

    2009-01-01

    Gas-cleaning techniques using nonthermal plasma are slowly introduced into industry nowadays. In this paper, we present a novel power modulator for the efficient generation of large-volume corona plasma. No expensive high-voltage components are required. Switching is done at an intermediate voltage

  5. Measurement of performance parameters of plasma source for plasma opening switch on Qiangguang-Ⅰ generator

    International Nuclear Information System (INIS)

    Luo Weixi; Zeng Zhengzhong; Lei Tianshi; Wang Liangping; Hu Yixiang; Sun Tieping; Huang Tao

    2012-01-01

    The plasma source (cable guns) of the plasma opening switch (POS) on Qiangguang Ⅰ generator was chosen as the study object. The plasma source performance was investigated by using charge collectors. Experimental results show that the plasma ejection density is positively correlated with the structural parameter, the distance between gun core tip and muzzle plane, and the plasma ejection velocity is negatively correlated with the parameter. The increasing rate of plasma ejection density is less than that of drive current. As far as a plasma source with tens of cable plasma guns is concerned, the influence of single cable gun's discharge dispersancy on plasma uniformity is little. Analysis of uncertainty shows that the uncertainty of measurement can be reduced by increasing the number of experiments and averaging the results. The combined standard uncertainty of plasma ejection density is less than 10%. (authors)

  6. Solar thermal organic rankine cycle for micro-generation

    Science.gov (United States)

    Alkahli, N. A.; Abdullah, H.; Darus, A. N.; Jalaludin, A. F.

    2012-06-01

    The conceptual design of an Organic Rankine Cycle (ORC) driven by solar thermal energy is developed for the decentralized production of electricity of up to 50 kW. Conventional Rankine Cycle uses water as the working fluid whereas ORC uses organic compound as the working fluid and it is particularly suitable for low temperature applications. The ORC and the solar collector will be sized according to the solar flux distribution in the Republic of Yemen for the required power output of 50 kW. This will be a micro power generation system that consists of two cycles, the solar thermal cycle that harness solar energy and the power cycle, which is the ORC that generates electricity. As for the solar thermal cycle, heat transfer fluid (HTF) circulates the cycle while absorbing thermal energy from the sun through a parabolic trough collector and then storing it in a thermal storage to increase system efficiency and maintains system operation during low radiation. The heat is then transferred to the organic fluid in the ORC via a heat exchanger. The organic fluids to be used and analyzed in the ORC are hydrocarbons R600a and R290.

  7. Non-equilibrium in flowing atmospheric plasmas

    International Nuclear Information System (INIS)

    Haas, J.C.M. de.

    1986-01-01

    This thesis deals with the fundamental aspects of two different plasmas applied in technological processes. The first one is the cesium seeded argon plasma in a closed cycle Magnetohydrodynamic (MHD) generator, the second is the thermal argon plasma in a cascade arc with an imposed flow. In Chapter 2 the influence of non-equilibrium on the mass and energy balances of a plasma is worked out. The general theory presented there can be applied to both the plasma in an MHD generator and to the cascade arc with imposed flow. Introductions to these plasmas are given in the Chapters 3 and 6 respectively. These chapters are both followed by two chapters which treat the theoretical and the experimental investigations. The results are summarized in Chapter 9. (Auth.)

  8. Chemically different non-thermal plasmas target distinct cell death pathways

    Czech Academy of Sciences Publication Activity Database

    Lunov, O.; Zablotskyy, V.; Chrupina, O.; Lunova, M.; Jirsa, M.; Dejneka, A.; Kubinová, Šárka

    2017-01-01

    Roč. 7, apr (2017), s. 600 ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LO1309 Institutional support: RVO:68378041 Keywords : chemically different * non-thermal plasmas * target distinct cell death pathways Subject RIV: FP - Other Medical Disciplines OBOR OECD: Biophysics Impact factor: 4.259, year: 2016

  9. Chemically reactive species in liquids generated by atmospheric-pressure plasmas and their roles in plasma medicine

    International Nuclear Information System (INIS)

    Hamaguchi, Satoshi

    2013-01-01

    Plasmas whose gas temperatures are close to room temperature may be generated in ambient air or a gas at atmospheric pressure with the use of low-frequency high voltage or low-power radio-frequency (RF) or microwave power applied to electrodes. Such plasmas can serve as a powerful source of free radicals and/or chemically reactive species that arise from atoms and molecules of the ambient gas. Recently use of such plasmas for medical purposes has attracted much attention as they can be implemented in possible medical devices that can cause blood coagulation, heal wounds, facilitate angiogenesis, sterilize surgical devices as well as living tissues without harming healthy cells, and selectively inactivate cancer cells. Especially of interest among reactive species generated by atmospheric-pressure plasmas (APP) are reactive oxygen species (ROS) and reactive nitrogen species (RNS) that are generated in liquid phase. Since most living tissues and cells are immersed in liquids (such as blood or culture media), reactive species generated by APPs in the gas phase are transported to the liquid phase and possibly converted to different types of reactive species therein before causing some influence on the tissues or cells. In this study, the rate equations are solved to evaluate concentrations of various reactive species in pure water that are originated by plasma reactions in atmosphere and possible effects of such species (including ROS/RNS) on living tissues and cells are discussed

  10. Chemically reactive species in liquids generated by atmospheric-pressure plasmas and their roles in plasma medicine

    Energy Technology Data Exchange (ETDEWEB)

    Hamaguchi, Satoshi [Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2013-07-11

    Plasmas whose gas temperatures are close to room temperature may be generated in ambient air or a gas at atmospheric pressure with the use of low-frequency high voltage or low-power radio-frequency (RF) or microwave power applied to electrodes. Such plasmas can serve as a powerful source of free radicals and/or chemically reactive species that arise from atoms and molecules of the ambient gas. Recently use of such plasmas for medical purposes has attracted much attention as they can be implemented in possible medical devices that can cause blood coagulation, heal wounds, facilitate angiogenesis, sterilize surgical devices as well as living tissues without harming healthy cells, and selectively inactivate cancer cells. Especially of interest among reactive species generated by atmospheric-pressure plasmas (APP) are reactive oxygen species (ROS) and reactive nitrogen species (RNS) that are generated in liquid phase. Since most living tissues and cells are immersed in liquids (such as blood or culture media), reactive species generated by APPs in the gas phase are transported to the liquid phase and possibly converted to different types of reactive species therein before causing some influence on the tissues or cells. In this study, the rate equations are solved to evaluate concentrations of various reactive species in pure water that are originated by plasma reactions in atmosphere and possible effects of such species (including ROS/RNS) on living tissues and cells are discussed.

  11. High order harmonic generation from plasma mirrors

    International Nuclear Information System (INIS)

    George, H.

    2010-01-01

    When an intense laser beam is focused on a solid target, the target's surface is rapidly ionized and forms dense plasma that reflects the incident field. For laser intensities above few 10 to the power of 15 Wcm -2 , high order harmonics of the laser frequency, associated in the time domain to a train of atto-second pulses (1 as 10 -18 s), can be generated upon this reflection. In this thesis, we developed numerical tools to reveal original aspects of harmonic generation mechanisms in three different interaction regime: the coherent wake emission, the relativistic emission and the resonant absorption. In particular, we established the role of these mechanisms when the target is a very thin foil (thickness of the order of 100 nm). Then we study experimentally the spectral, spatial and coherence properties of the emitted light. We illustrate how to exploit these measurements to get information on the plasma mirror dynamics on the femtosecond and atto-second time scales. Last, we propose a technique for the single-shot complete characterization of the temporal structure of the harmonic light emission from the laser-plasma mirror interaction. (author)

  12. Temperature simulation of thermal plasma melting furnace for disposal of radioactive waste and preliminary research of vitrification formula

    International Nuclear Information System (INIS)

    Lin Peng; Lu Yonghong; Xiang Wenyuan; Chen Mingzhou; Liu Xiajie; Qin Yuxin

    2013-01-01

    Radioactive waste treatment techniques currently used in nuclear power plant increase the volume greatly and bring much pressure on final disposal; Thermal plasma treatment as a crucial technique to reduce the waste volume is introduced. How to improve the efficiency of the plasma energy is the limiting factor of concern. In this paper, the temperature field of thermal plasma melting furnace is simulated, the maximal temperature of fixed bed melting furnace is calculated (about 1445 ℃). According to the optional fire-resistant materials, the feasibility of furnace fabrication is discussed. Vitrification formulas for three typical radioactive wastes are tested with their feasibilities being analyzed then. Finally, the prospect of thermal plasma techniques of radioactive waste is discussed, and issues for future study are raised. (authors)

  13. Inflight dissociation of zircon in air plasma

    Energy Technology Data Exchange (ETDEWEB)

    Yugeswaran, S; Selvarajan, V [Bharathiar University, Coimbatore 641046 (India); Ananthapadmanabhan, P V; Thiyagarajan, T K [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai - 400 085 (India); Nair, Janardhanan [Ion Arc Technologies Pvt Ltd, Coimbatore (India)

    2010-02-01

    Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO{sub 2} and silica could be accomplished at 25 kW in air plasma.

  14. Inflight dissociation of zircon in air plasma

    International Nuclear Information System (INIS)

    Yugeswaran, S; Selvarajan, V; Ananthapadmanabhan, P V; Thiyagarajan, T K; Nair, Janardhanan

    2010-01-01

    Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO 2 and silica could be accomplished at 25 kW in air plasma.

  15. Economic impact of latent heat thermal energy storage systems within direct steam generating solar thermal power plants with parabolic troughs

    International Nuclear Information System (INIS)

    Seitz, M.; Johnson, M.; Hübner, S.

    2017-01-01

    Highlights: • Integration of a latent heat thermal energy storage system into a solar direct steam generation power cycle. • Parametric study of solar field and storage size for determination of the optimal layout. • Evaluation of storage impact on the economic performance of the solar thermal power plant. • Economic comparison of new direct steam generation plant layout with state-of-the-art oil plant layout. - Abstract: One possible way to further reduce levelized costs of electricity of concentrated solar thermal energy is to directly use water/steam as the primary heat transfer fluid within a concentrated collector field. This so-called direct steam generation offers the opportunity of higher operating temperatures and better exergy efficiency. A technical challenge of the direct steam generation technology compared to oil-driven power cycles is a competitive storage technology for heat transfer fluids with a phase change. Latent heat thermal energy storages are suitable for storing heat at a constant temperature and can be used for direct steam generation power plants. The calculation of the economic impact of an economically optimized thermal energy storage system, based on a latent heat thermal energy storage system with phase change material, is the main focus of the presented work. To reach that goal, a thermal energy storage system for a direct steam generation power plant with parabolic troughs in the solar field was thermally designed to determine the boundary conditions. This paper discusses the economic impact of the designed thermal energy storage system based on the levelized costs of electricity results, provided via a wide parametric study. A state-of-the-art power cycle with a primary and a secondary heat transfer fluid and a two-tank thermal energy storage is used as a benchmark technology for electricity generation with solar thermal energy. The benchmark and direct steam generation systems are compared to each other, based respectively

  16. On reliability of 3D reconstructions of thermal plasma jet radiation by inverse Radon transform

    Czech Academy of Sciences Publication Activity Database

    Sekerešová, Zuzana; Hlína, Jan

    2011-01-01

    Roč. 56, č. 2 (2011), s. 171-183 ISSN 0001-7043 Institutional research plan: CEZ:AV0Z20570509 Keywords : thermal plasma jet * tomography * image reconstruction Subject RIV: BL - Plasma and Gas Discharge Physics

  17. Modeling and Data Needs of Atmospheric Pressure Gas Plasma and Biomaterial Interaction

    International Nuclear Information System (INIS)

    Sakiyama, Yukinori; Graves, David B.

    2009-01-01

    Non-thermal atmospheric pressure plasmas have received considerable attention recently. One promising application of non-thermal plasma devices appears to be biomaterial and biomedical treatment. Various biological and medical effects of non-thermal plasmas have been observed by a variety of investigators, including bacteria sterilization, cell apoptosis, and blood coagulation, among others. The mechanisms of the plasma-biomaterial interaction are however only poorly understood. A central scientific challenge is therefore how to answer the question: 'What plasma-generated agents are responsible for the observed biological effects?' Our modeling efforts are motivated by this question. In this paper, we review our modeling results of the plasma needle discharge. Then, we address data needs for further modeling and understanding of plasma-biomaterial interaction

  18. Application of Response Surface Methodology for characterization of ozone production from Multi-Cylinder Reactor in non-thermal plasma device

    Science.gov (United States)

    Lian See, Tan; Zulazlan Shah Zulkifli, Ahmad; Mook Tzeng, Lim

    2018-04-01

    Ozone is a reactant which can be applied for various environmental treatment processes. It can be generated via atmospheric air non-thermal plasmas when sufficient voltages are applied through a combination of electrodes and dielectric materials. In this study, the concentration of ozone generated via two different configurations of multi-cylinder dielectric barrier discharge (DBD) reactor (3 x 40 mm and 10 x 10 mm) was investigated. The influence of the voltage and the duty cycle to the concentration of ozone generated by each configuration was analysed using response surface methodology. Voltage was identified as significant factor to the ozone production process. However, the regressed model was biased towards one of the configuration, leaving the predicted results of another configuration to be out of range.

  19. Operational characteristics of the high flux plasma generator Magnum-PSI

    Energy Technology Data Exchange (ETDEWEB)

    Eck, H.J.N. van, E-mail: h.j.n.vaneck@differ.nl [FOM Institute DIFFER, Dutch Institute For Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Abrams, T. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Berg, M.A. van den; Brons, S.; Eden, G.G. van [FOM Institute DIFFER, Dutch Institute For Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Jaworski, M.A.; Kaita, R. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Meiden, H.J. van der; Morgan, T.W.; Pol, M.J. van de; Scholten, J.; Smeets, P.H.M.; De Temmerman, G.; Vries, P.C. de; Zeijlmans van Emmichoven, P.A. [FOM Institute DIFFER, Dutch Institute For Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands)

    2014-10-15

    Highlights: •We have described the design and capabilities of the plasma experiment Magnum-PSI. •The plasma conditions are well suited for PSI studies in support of ITER. •Quasi steady state heat fluxes over 10 MW m{sup −2} have been achieved. •Transient heat and particle loads can be generated to simulate ELM instabilities. •Lithium coating can be applied to the surfaces of samples under vacuum. -- Abstract: In Magnum-PSI (MAgnetized plasma Generator and NUMerical modeling for Plasma Surface Interactions), the high density, low temperature plasma of a wall stabilized dc cascaded arc is confined to a magnetized plasma beam by a quasi-steady state axial magnetic field up to 1.3 T. It aims at conditions that enable fundamental studies of plasma–surface interactions in the regime relevant for fusion reactors such as ITER: 10{sup 23}–10{sup 25} m{sup −2} s{sup −1} hydrogen plasma flux densities at 1–5 eV. To study the effects of transient heat loads on a plasma-facing surface, a high power pulsed magnetized arc discharge has been developed. Additionally, the target surface can be transiently heated with a pulsed laser system during plasma exposure. In this contribution, the current status, capabilities and performance of Magnum-PSI are presented.

  20. Parametric analysis of the thermal effects on the divertor in tokamaks during plasma disruptions

    International Nuclear Information System (INIS)

    Bruhn, M.L.

    1988-04-01

    Plasma disruptions are an ever present danger to the plasma-facing components in today's tokamak fusion reactors. This threat results from our lack of understanding and limited ability to control this complex phenomenon. In particular, severe energy deposition occurs on the divertor component of the double-null configured tokamak reactor during such disruptions. A hybrid computational model developed to estimate and graphically illustrate global thermal effects of disruptions on the divertor plates is described in detail. The quasi-two-dimensional computer code, TADDPAK (Thermal Analysis Divertor during Disruptions PAcKage), is used to conduct parametric analysis for the TIBER II Tokamak Engineering Test Reactor Design. The dependence of these thermal effects on divertor material choice, disruption pulse length, disruption pulse shape, and the characteristic thickness of the plasma scrape-off layer is investigated for this reactor design. Results and conclusions from this analysis are presented. Improvements to this model and issues that require further investigation are discussed. Cursory analysis for ITER (International Thermonuclear Experimental Reactor) is also presented in the appendix. 75 refs., 49 figs., 10 tabs

  1. Reversible switching of wetting properties and erasable patterning of polymer surfaces using plasma oxidation and thermal treatment

    Science.gov (United States)

    Rashid, Zeeshan; Atay, Ipek; Soydan, Seren; Yagci, M. Baris; Jonáš, Alexandr; Yilgor, Emel; Kiraz, Alper; Yilgor, Iskender

    2018-05-01

    Polymer surfaces reversibly switchable from superhydrophobic to superhydrophilic by exposure to oxygen plasma and subsequent thermal treatment are demonstrated. Two inherently different polymers, hydrophobic segmented polydimethylsiloxane-urea copolymer (TPSC) and hydrophilic poly(methyl methacrylate) (PMMA) are modified with fumed silica nanoparticles to prepare superhydrophobic surfaces with roughness on nanometer to micrometer scale. Smooth TPSC and PMMA surfaces are also used as control samples. Regardless of their chemical structure and surface topography, all surfaces display completely reversible wetting behavior changing from hydrophobic to hydrophilic and back for many cycles upon plasma oxidation followed by thermal annealing. Influence of plasma power, plasma exposure time, annealing temperature and annealing time on the wetting behavior of polymeric surfaces are investigated. Surface compositions, textures and topographies are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and white light interferometry (WLI), before and after oxidation and thermal annealing. Wetting properties of the surfaces are determined by measuring their static, advancing and receding water contact angle. We conclude that the chemical structure and surface topography of the polymers play a relatively minor role in reversible wetting behavior, where the essential factors are surface oxidation and migration of polymer molecules to the surface upon thermal annealing. Reconfigurable water channels on polymer surfaces are produced by plasma treatment using a mask and thermal annealing cycles. Such patterned reconfigurable hydrophilic regions can find use in surface microfluidics and optofluidics applications.

  2. Plasma blob generation due to cooperative elliptic instability.

    Science.gov (United States)

    Manz, P; Xu, M; Müller, S H; Fedorczak, N; Thakur, S C; Yu, J H; Tynan, G R

    2011-11-04

    Using fast-camera measurements the generation mechanism of plasma blobs is investigated in the linear device CSDX. During the ejection of plasma blobs the plasma is dominated by an m=1 mode, which is a counterrotating vortex pair. These flows are known to be subject to the cooperative elliptic instability, which is characterized by a cooperative disturbance of the vortex cores and results in a three-dimensional breakdown of two-dimensional flows. The first experimental evidence of a cooperative elliptic instability preceding the blob-ejection is provided in terms of the qualitative evolution of the vortex geometries and internal wave patterns.

  3. Measurement of thermal plasma jet temperature and velocity by laser light lineshape analysis

    International Nuclear Information System (INIS)

    Snyder, S.C.; Reynolds, L.D.

    1991-01-01

    Two important parameters of thermal plasma jets are kinetic or gas temperatures and flow velocity. Gas temperatures have been traditionally measured using emission spectroscopy, but this method depends on either the generally unrealistic assumption of the existence of local thermodynamic equilibrium (LTE) within the plasma, or the use of various non-LTE or partial LTE models to relate the intensity of the emission lines to the gas temperature. Plasma jet velocities have been measured using laser Doppler velocimetry on particles injected into the plasma. However, this method is intrusive and it is not known how well the particle velocities represent the gas velocity. Recently, plasma jet velocities have been measured from the Doppler shift of laser light scattered by the plasma. In this case, the Doppler shift was determined from the difference in the transmission profile of a high resolution monochromator between red shifted and blue shifted scattered light. A direct approach to measuring localized temperatures and velocities is afforded by high resolution scattered light lineshape measurements. The linewidth of laser light scattered by atoms and ions can be related to the kinetic temperature without LTE assumptions, while a shift in the peak position relative to the incident laser lineshape yields the gas velocity. We report in this paper work underway to measure gas temperatures and velocities in an argon thermal plasma jet using high resolution lineshape analysis of scattered laser light

  4. Extreme hydrogen plasma densities achieved in a linear plasma generator

    NARCIS (Netherlands)

    Rooij, van G.J.; Veremiyenko, V.P.; Goedheer, W.J.; Groot, de B.; Kleyn, A.W.; Smeets, P.H.M.; Versloot, T.W.; Whyte, D.G.; Engeln, R.A.H.; Schram, D.C.; Lopes Cardozo, N.J.

    2007-01-01

    A magnetized hydrogen plasma beam was generated with a cascaded arc, expanding in a vacuum vessel at an axial magnetic field of up to 1.6 T. Its characteristics were measured at a distance of 4 cm from the nozzle: up to a 2 cm beam diameter, 7.5×1020 m-3 electron density, ~2 eV electron and ion

  5. The Quark-Gluon Plasma Collective Dynamics and Hard Thermal Loops

    CERN Document Server

    Blaizot, J P; Blaizot, Jean-Paul; Iancu, Edmond

    2002-01-01

    We present a unified description of the high temperature phase of QCD, the so-called quark-gluon plasma, in a regime where the effective gauge coupling $g$ is sufficiently small to allow for weak coupling calculations. The main focuss is the construction of the effective theory for the collective excitations which develop at a typical scale $gT$, which is well separated from the typical energy of single particle excitations which is the temperature $T$. We show that the plasma particles provide a source for long wavelength oscillations of average fields which carry the quantum numbers of the plasma constituents, the quarks and the gluons. To leading order in $g$, the plasma particles obey simple gauge-covariant kinetic equations, whose derivation from the general Dyson-Schwinger equations is outlined. As a by-product, the ``hard thermal loops'' emerge naturally in a physically transparent framework. We show that the collective excitations can be described in terms of classical fields, and develop for these a ...

  6. Diffuse plasma treatment of polyamide 66 fabric in atmospheric pressure air

    International Nuclear Information System (INIS)

    Li, Lee; Peng, Ming-yang; Teng, Yun; Gao, Guozhen

    2016-01-01

    Graphical abstract: - Highlights: • A cylindrical-electrode nanosecond-pulse diffuse-discharge reactor is presented. • Large-scale non-thermal plasmas were generated steadily in atmospheric air. • Treated PA66 fabric is etched with oxygen-containing group increases. • The hydrophily of treated PA66 fabric improves effectively. • Extending the treatment time is a method to reduce the treatment frequency. - Abstract: The polyamide 66 (PA66) fabrics are hard to be colored or glued in industrial production due to the poor hydrophily. Diffuse plasma is a kind of non-thermal plasma generated at atmospheric pressure in air. This paper proposes that large-scale diffuse plasma generated between wire electrodes can be employed for improving the hydrophily of PA66 fabrics. A repetitive nanosecond-pulse diffuse-discharge reactor using a cylindrical wire electrode configuration is presented, which can generate large-scale non-thermal plasmas steadily at atmospheric pressure without any barrier dielectric. Then the reactor is used to treat PA66 fabrics in different discharge conditions. The hydrophilicity property of modified PA66 is measured by wicking test method. The modified PA66 is also analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) to prove the surface changes in physical microstructure and chemical functional groups, respectively. What's more, the effects of treatment time and treatment frequency on surface modification are investigated and discussed.

  7. Novel Therapeutic Effects of Non-thermal atmospheric pressure plasma for Muscle Regeneration and Differentiation

    Science.gov (United States)

    Choi, Jae Won; Kang, Sung Un; Kim, Yang Eun; Park, Ju Kyeong; Yang, Sang Sik; Kim, Yeon Soo; Lee, Yun Sang; Lee, Yuijina; Kim, Chul-Ho

    2016-01-01

    Skeletal muscle can repair muscle tissue damage, but significant loss of muscle tissue or its long-lasting chronic degeneration makes injured skeletal muscle tissue difficult to restore. It has been demonstrated that non-thermal atmospheric pressure plasma (NTP) can be used in many biological areas including regenerative medicine. Therefore, we determined whether NTP, as a non-contact biological external stimulator that generates biological catalyzers, can induce regeneration of injured muscle without biomaterials. Treatment with NTP in the defected muscle of a Sprague Dawley (SD) rat increased the number of proliferating muscle cells 7 days after plasma treatment (dapt) and rapidly induced formation of muscle tissue and muscle cell differentiation at 14 dapt. In addition, in vitro experiments also showed that NTP could induce muscle cell proliferation and differentiation of human muscle cells. Taken together, our results demonstrated that NTP promotes restoration of muscle defects through control of cell proliferation and differentiation without biological or structural supporters, suggesting that NTP has the potential for use in muscle tissue engineering and regenerative therapies. PMID:27349181

  8. Measurement of x-ray emission and thermal transport in near-solid-density plasmas heated by 130 fs laser pulses

    International Nuclear Information System (INIS)

    Young, B.K.; Wilson, B.G.; Price, D.F.; Stewart, R.E.

    1998-01-01

    Near-solid-density plasmas with peak temperatures of 370±50 eV have been generated using a high-contrast (∼10 -7 ), 400 nm, 130 fs laser pulse of intensity 3x10 17 Wcm -2 at the Ultrashort Pulse Laser at Lawrence Livermore National Laboratory. The x-ray-emission spectra from thin tracer layers of germanium, tamped by layers of plastic, were measured as a function of target depth. The results qualitatively agree with calculations based on detailed local thermodynamic equilibrium (LTE) and modified non-LTE spectroscopic opacity models using plasma conditions determined using LASNEX hydrodynamic simulations. No evidence of thermal flux inhibition into the bulk target material was observed. The experiments and detailed simulations are presented. copyright 1998 The American Physical Society

  9. Effects of non-thermal plasmas and electric field on hydrocarbon/air flames

    Science.gov (United States)

    Ganguly, Biswa

    2009-10-01

    Need to improve fuel efficiency, and reduce emission from hydrocarbon combustor in automotive and gas turbine engines have reinvigorated interest in reducing combustion instability of a lean flame. The heat generation rate in a binary reaction is HQ =N^2 c1c2 Q exp(-E/RT), where N is the density, c1 and c2 are mol fractions of the reactants, Q is the reaction heat release, E is the activation energy, R is the gas constant and T is the average temperature. For hydrocarbon-air reactions, the typical value of E/R ˜20, so most heat release reactions are confined to a thin reaction sheet at T >=1400 K. The lean flame burning condition is susceptible to combustion instability due to a critical balance between heat generation and heat loss rates, especially at high gas flow rate. Radical injection can increase flame speed by reducing the hydrocarbon oxidation reaction activation barrier and it can improve flame stability. Advances in nonequilibrium plasma generation at high pressure have prompted its application for energy efficient radical production to enhance hydrocarbon-air combustion. Dielectric barrier discharges and short pulse excited corona discharges have been used to enhance combustion stability. Direct electron impact dissociation of hydrocarbon and O2 produces radicals with lower fuel oxidation reaction activation barriers, initiating heat release reaction CnHm+O CnHm-1+ OH (and other similar sets of reactions with partially dissociated fuel) below the typical cross-over temperature. Also, N2 (A) produced in air discharge at a moderate E/n can dissociate O2 leading to oxidation of fuel at lower gas temperature. Low activation energy reactions are also possible by dissociation of hydrocarbon CnHm+e -> CnHm-2+H2+e, where a chain propagation reaction H2+ O OH+H can be initiated at lower gas temperature than possible under thermal equilibrium kinetics. Most of heat release comes from the reaction CO+OH-> CO2 +H, nonthermal OH production seem to improve

  10. Thermal Expansion of Vacuum Plasma Sprayed Coatings

    Science.gov (United States)

    Raj, S V.; Palczer, A. R.

    2010-01-01

    Metallic Cu-8%Cr, Cu-26%Cr, Cu-8%Cr-1%Al, NiAl and NiCrAlY monolithic coatings were fabricated by vacuum plasma spray deposition processes for thermal expansion property measurements between 293 and 1223 K. The corrected thermal expansion, (DL/L(sub 0) varies with the absolute temperature, T, as (DL/L(sub 0) = A(T - 293)(sup 3) + BIT - 293)(sup 2) + C(T - 293) + D, where, A, B, C and D are thermal, regression constants. Excellent reproducibility was observed for all of the coatings except for data obtained on the Cu-8%Cr and Cu-26%Cr coatings in the first heat-up cycle, which deviated from those determined in the subsequent cycles. This deviation is attributed to the presence of residual stresses developed during the spraying of the coatings, which are relieved after the first heat-up cycle. In the cases of Cu-8%Cr and NiAl, the thermal expansion data were observed to be reproducible for three specimens. The linear expansion data for Cu-8% Cr and Cu-26%Cr agree extremely well with rule of mixture (ROM) predictions. Comparison of the data for the Cu-8%Cr coating with literature data for Cr and Cu revealed that the thermal expansion behavior of this alloy is determined by the Cu-rich matrix. The data for NiAl and NiCrAlY are in excellent agreement with published results irrespective of composition and the methods used for processing the materials. The implications of these results on coating GRCop-84 copper alloy combustor liners for reusable launch vehicles are discussed.

  11. A thermodynamic model of plasma generation by pulsed laser irradiation in vacuum

    CERN Document Server

    Tosto, S

    2003-01-01

    This paper introduces a thermodynamic model to determine composition, temperature and pressure of the plasma cloud induced by pulsed laser irradiation in the case where a relevant thermal sputtering mechanism is operating at the surface of a molten layer. The model concerns in particular pulse lengths of the order of several nanoseconds and completes the results of a previous paper concerning the physics of the evaporation and boiling driven thermal sputtering (Tosto S 2002 J. Phys. D: Appl. Phys. 35); the recession rate and temperature at the molten surface are linked to the pulse fluence and plasma properties in the frame of a unique physical model. This paper shows that the plasma properties depend critically on the non-equilibrium character of the surface evaporation and boiling mechanisms. The extension of the model to the case of continuous laser irradiation is also discussed. Some examples of computer simulation aim to show the results available in the particular case of a metal target; the comparison ...

  12. Electricity pricing model in thermal generating stations under deregulation

    International Nuclear Information System (INIS)

    Reji, P.; Ashok, S.; Moideenkutty, K.M.

    2007-01-01

    In regulated public utilities with competitive power markets, deregulation has replaced the monopoly. Under the deregulated power market, the electricity price primarily depends on market mechanism and power demand. In this market, generators generally follow marginal pricing. Each generator fixes the electricity price based on their pricing strategy and it leads to more price volatility. This paper proposed a model to determine the electricity price considering all operational constraints of the plant and economic variables that influenced the price, for a thermal generating station under deregulation. The purpose of the model was to assist existing stations, investors in the power sector, regulatory authorities, transmission utilities, and new power generators in decision-making. The model could accommodate price volatility in the market and was based on performance incentive/penalty considering plant load factor, availability of the plant and peak/ off peak demand. The model was applied as a case study to a typical thermal utility in India to determine the electricity price. It was concluded that the case study of a thermal generating station in a deregulated environment showed that the electricity price mainly depended on the gross calorific value (GCV) of fuel, mode of operation, price of the fuel, and operating charges. 11 refs., 2 tabs., 1 fig

  13. Thermal energy and bootstrap current in fusion reactor plasmas

    International Nuclear Information System (INIS)

    Becker, G.

    1993-01-01

    For DT fusion reactors with prescribed alpha particle heating power P α , plasma volume V and burn temperature i > ∼ 10 keV specific relations for the thermal energy content, bootstrap current, central plasma pressure and other quantities are derived. It is shown that imposing P α and V makes these relations independent of the magnitudes of the density and temperature, i.e. they only depend on P α , V and shape factors or profile parameters. For model density and temperature profiles analytic expressions for these shape factors and for the factor C bs in the bootstrap current formula I bs ∼ C bs (a/R) 1/2 β p I p are given. In the design of next-step devices and fusion reactors, the fusion power is a fixed quantity. Prescription of the alpha particle heating power and plasma volume results in specific relations which can be helpful for interpreting computer simulations and for the design of fusion reactors. (author) 5 refs

  14. Laser plasma simulations of the generation processes of Alfven and collisionless shock waves in space plasma

    International Nuclear Information System (INIS)

    Prokopov, P A; Zakharov, Yu P; Tishchenko, V N; Shaikhislamov, I F; Boyarintsev, E L; Melekhov, A V; Ponomarenko, A G; Posukh, V G; Terekhin, V A

    2016-01-01

    Generation of Alfven waves propagating along external magnetic field B 0 and Collisionless Shock Waves propagating across B 0 are studied in experiments with laser- produced plasma and magnetized background plasma. The collisionless interaction of interpenetrating plasma flows takes place through a so-called Magnetic Laminar Mechanism (MLM) or Larmor Coupling. At the edge of diamagnetic cavity LP-ions produce induction electric field E φ which accelerates BP-ions while LP-ions rotate in opposite direction. The ions movement generates sheared azimuthal magnetic field B φ which could launches torsional Alfven wave. In previous experiments at KI-1 large scale facility a generation of strong perturbations propagating across B 0 with magnetosonic speed has been studied at a moderate value of interaction parameter δ∼0.3. In the present work we report on experiments at conditions of 5∼R2 and large Alfven-Mach number M A ∼10 in which strong transverse perturbations traveling at a scale of ∼1 m in background plasma at a density of ∼3*10 13 cm -3 is observed. At the same conditions but smaller M A ∼ 2 a generation, the structure and dynamic of Alfven wave with wavelength ∼0.5 m propagating along fields B 0 ∼100÷500 G for a distance of ∼2.5 m is studied. (paper)

  15. Electron-beam generated plasmas for processing applications

    Science.gov (United States)

    Meger, Robert; Leonhardt, Darrin; Murphy, Donald; Walton, Scott; Blackwell, David; Fernsler, Richard; Lampe, Martin; Manheimer, Wallace

    2001-10-01

    NRL's Large Area Plasma Processing System (LAPPS) utilizes a 5-10 mA/cm^2, 2-4 kV, 1 cm x 30-60 cm cross section beam of electrons guided by a magnetic field to ionize a low density (10-100 mTorr) gas.[1] Beam ionization allows large area, high density, low temperature plasmas to be generated in an arbitrary gas mixture at a well defined location. Energy and composition of particle fluxes to surfaces on both sides of the plasma can be controlled by gas mixture, location, rf bias, and other factors. Experiments have been performed using both pulsed and cw beams. Extensive diagnostics (Langmuir probes, mass and ion energy analyzers, optical emissions, microwave interferometry, etc.) have been fielded to measure the plasma properties and neutral particle fluxes (ions, neutrals, free radicals) with and without rf bias on nearby surfaces both with the beam on and off. Uniform, cold (Te < 1eV), dense (ne 10^13 cm-3) plasmas in molecular and atomic gases and mixtures thereof have been produced in agreement with theoretical expectations. Initial tests of LAPPS application such as ashing, etching, sputtering, and diamond growth have been performed. Program status will be presented. [1]R.A. Meger, et al, Phys. of Plasmas 8(5), p. 2558 (2001)

  16. A Nanosecond Pulsed Plasma Brush for Surface Decontamination

    Science.gov (United States)

    Neuber, Johanna; Malik, Muhammad; Song, Shutong; Jiang, Chunqi

    2015-11-01

    This work optimizes a non-thermal, atmospheric pressure plasma brush for surface decontamination. The generated plasma plumes with a maximum length of 2 cm are arranged in a 5 cm long, brush-like array. The plasma was generated in ambient air with Acinetobacter baumannii. Laminate surfaces inoculated with over-night cultured bacteria were subject to the plasma treatment for varying water concentrations in He, flow rates and discharge voltages. It was found that increasing the water content of the feed gas greatly enhanced the bactericidal effect. Emission spectroscopy was performed to identify the reactive plasma species that contribute to this variation. Additional affiliation: Frank Reidy Research Center for Bioelectrics

  17. Distributed generation incorporated with the thermal generation for optimum operation of a smart grid considering forecast error

    International Nuclear Information System (INIS)

    Howlader, Harun Or Rashid; Matayoshi, Hidehito; Senjyu, Tomonobu

    2015-01-01

    Highlights: • Optimal operation of the thermal generation for the smart grid system. • Different distributed generations are considered as the power generation sources. • Forecast error of the renewable energy systems is considered. • Controllable loads of the smart houses are considered to achieve the optimal operation. • Economical benefits can be achieved for the smart grid system. - Abstract: This paper concentrates on the optimal operation of the conventional thermal generators with distributed generations for a smart grid considering forecast error. The distributed generations are considered as wind generators, photovoltaic generators, battery energy storage systems in the supply side and a large number of smart houses in the demand side. A smart house consists of the electric vehicle, heat pump, photovoltaic generator and solar collector. The electric vehicle and heat pump are considered as the controllable loads which can compensate the power for the forecast error of renewable energy sources. As a result, power generation cost of the smart grid can reduce through coordinated with distributed generations and thermal units scheduling process. The electric vehicles of the smart house are considered as the spinning reserve in the scheduling process which lead to lessen the additional operation of thermal units. Finally, obtained results of the proposed system have been compared with the conventional method. The conventional method does not consider the electric vehicle in the smart houses. The acquired results demonstrate that total power generation cost of the smart grid has been reduced by the proposed method considering forecast error. Effectiveness of the proposed method has been verified by the extensive simulation results using MATLAB® software

  18. Study of the stacked plasma generator of Maecker type

    International Nuclear Information System (INIS)

    Shirai, Hiroyuki; Tabei, Katsuine; Machida, Ichiro; Ishihara, Kimio.

    1981-01-01

    An experimental investigation of a stacked plasma generator of Maecker type has been performed at low pressures (25 - 760 Torr) and low electric currents (10 - 60 A) for argon gas. Radial distributions of electron density and electron temperature were obtained by measuring the intensities of spectral lines and continuum from cylindrically confined plasmas. Based on such data of the macroscopic plasma parameters, the SAHA equilibrium relation, and the collisional and radiative theory of BATES et al., the spatial extent of equilibrium region and nonequilibrium effects of electronic excitation of the atom have been examined. In the plasmas generated in the apparatus, electron temperature ranged from 7,500 to 11,000 0 K and electron density 7 x 10 14 to 3 x 10 16 cm -3 . It was found that thermochemical equilibrium conditions existed only in the vicinity of the tube axis even at relatively high pressures and high currents, and the higher excited levels than the 5p level of argon atom were always in SAHA equilibrium with free electrons. (author)

  19. Cold plasma brush generated at atmospheric pressure

    International Nuclear Information System (INIS)

    Duan Yixiang; Huang, C.; Yu, Q. S.

    2007-01-01

    A cold plasma brush is generated at atmospheric pressure with low power consumption in the level of several watts (as low as 4 W) up to tens of watts (up to 45 W). The plasma can be ignited and sustained in both continuous and pulsed modes with different plasma gases such as argon or helium, but argon was selected as a primary gas for use in this work. The brush-shaped plasma is formed and extended outside of the discharge chamber with typical dimension of 10-15 mm in width and less than 1.0 mm in thickness, which are adjustable by changing the discharge chamber design and operating conditions. The brush-shaped plasma provides some unique features and distinct nonequilibrium plasma characteristics. Temperature measurements using a thermocouple thermometer showed that the gas phase temperatures of the plasma brush are close to room temperature (as low as 42 deg. C) when running with a relatively high gas flow rate of about 3500 ml/min. For an argon plasma brush, the operating voltage from less than 500 V to about 2500 V was tested, with an argon gas flow rate varied from less than 1000 to 3500 ml/min. The cold plasma brush can most efficiently use the discharge power as well as the plasma gas for material and surface treatment. The very low power consumption of such an atmospheric argon plasma brush provides many unique advantages in practical applications including battery-powered operation and use in large-scale applications. Several polymer film samples were tested for surface treatment with the newly developed device, and successful changes of the wettability property from hydrophobic to hydrophilic were achieved within a few seconds

  20. Nonlinear electron-acoustic rogue waves in electron-beam plasma system with non-thermal hot electrons

    Science.gov (United States)

    Elwakil, S. A.; El-hanbaly, A. M.; Elgarayh, A.; El-Shewy, E. K.; Kassem, A. I.

    2014-11-01

    The properties of nonlinear electron-acoustic rogue waves have been investigated in an unmagnetized collisionless four-component plasma system consisting of a cold electron fluid, non-thermal hot electrons obeying a non-thermal distribution, an electron beam and stationary ions. It is found that the basic set of fluid equations is reduced to a nonlinear Schrodinger equation. The dependence of rogue wave profiles on the electron beam and energetic population parameter are discussed. The results of the present investigation may be applicable in auroral zone plasma.

  1. Modeling of thermal effects on TIBER II divertor during plasma disruptions

    International Nuclear Information System (INIS)

    Bruhn, M.L.; Perkins, L.J.

    1987-01-01

    Mapping the disruption power flow from the mid-plane of the TIBER Engineering Test Reactor to its divertor and calculating the resulting thermal effects are accomplished through the modification and coupling of three presently existing computer codes. The resulting computer code TADDPAK (Thermal Analysis Divertor during Disruption PAcKage) provides three-dimensional graphic presentations of time and positional dependent thermal effects on a poloidal cross section of the double-null-divertor configured reactor. These thermal effects include incident heat flux, surface temperature, vaporization rate, total vaporization, and melting depth. The dependence of these thermal effects on material choice, disruption pulse shape, and the characteristic thickness of the plasma scrape-off layer is determined through parametric analysis with TADDPAK. This computer code is designed to be a convenient, rapid, and user-friendly modeling tool which can be easily adapted to most tokamak double-null-divertor reactor designs

  2. Solar thermal electric power generation - an attractive option for Pakistan

    International Nuclear Information System (INIS)

    Khan, N.A

    1999-01-01

    Solar Thermal Energy is being successfully used for production of electricity in few developed countries for more than 10 years. In solar Electric Generating Systems high temperature is generated by concentrating solar energy on black absorber pipe in evacuated glass tubes. This heat is absorbed and transported with the help of high temperature oil in to highly insulated heat exchanger storage tanks. They are subsequently used to produce steam that generates power through steam turbines as in standard thermal power plants. Various components involved in Solar thermal field have been developed at the Solar Systems Laboratory of College of EME, NUST Rawalpindi. It is considered as a cost effective alternate for power generation. The research has been partially sponsored by Ministry of Science and Technology under its Public Sector Development Program (PSDP) in (1996-1998). Parabolic mirror design, fabrication, polishing, installation, solar tracking, absorber pipe, glass tubes, steam generation al have been developed. This paper will cover the details of indigenous technological break through made in this direction. (author)

  3. Simple microwave plasma source at atmospheric pressure

    International Nuclear Information System (INIS)

    Kim, Jeong H.; Hong, Yong C.; Kim, Hyoung S.; Uhm, Han S.

    2003-01-01

    We have developed a thermal plasma source operating without electrodes. One electrodeless torch is the microwave plasma-torch, which can produce plasmas in large quantities. We can generate plasma at an atmospheric pressure by marking use of the same magnetrons used as commercial microwave ovens. Most of the magnetrons are operated at the frequency of 2.45 GHz; the magnetron power microwave is about 1kW. Electromagnetic waves from the magnetrons propagate through a shorted waveguide. Plasma was generated under a resonant condition, by an auxiliary ignition system. The plasma is stabilized by vortex stabilization. Also, a high-power and high-efficiency microwave plasma-torch has been operated in air by combining two microwave plasma sources with 1kW, 2.45 GHz. They are arranged in series to generate a high-power plasma flame. The second torch adds all its power to the plasma flame of the first torch. Basically, electromagnetic waves in the waveguide were studied by a High Frequency Structure Simulator (HFSS) code and preliminary experiments were conducted

  4. Numerical modeling of disperse material evaporation in axisymmetric thermal plasma reactor

    Directory of Open Access Journals (Sweden)

    Stefanović Predrag Lj.

    2003-01-01

    Full Text Available A numerical 3D Euler-Lagrangian stochastic-deterministic (LSD model of two-phase flow laden with solid particles was developed. The model includes the relevant physical effects, namely phase interaction, panicle dispersion by turbulence, lift forces, particle-particle collisions, particle-wall collisions, heat and mass transfer between phases, melting and evaporation of particles, vapour diffusion in the gas flow. It was applied to simulate the processes in thermal plasma reactors, designed for the production of the ceramic powders. Paper presents results of extensive numerical simulation provided (a to determine critical mechanism of interphase heat and mass transfer in plasma flows, (b to show relative influence of some plasma reactor parameters on solid precursor evaporation efficiency: 1 - inlet plasma temperature, 2 - inlet plasma velocity, 3 - particle initial diameter, 4 - particle injection angle a, and 5 - reactor wall temperature, (c to analyze the possibilities for high evaporation efficiency of different starting solid precursors (Si, Al, Ti, and B2O3 powder, and (d to compare different plasma reactor configurations in conjunction with disperse material evaporation efficiency.

  5. On the energy deposition into the plasma for an inverted fireball geometry

    Science.gov (United States)

    Levko, Dmitry; Gruenwald, Johannes

    2017-10-01

    Energy deposition into a plasma for an inverted fireball geometry is studied using a self-consistent two-dimensional Particle-in-Cell Monte Carlo collision model. In this model, the cathode is a pin which injects the fixed electron current and the anode is a hollow metal tube covered with the metal grid. We obtain an almost constant ratio between the densities of plasmas generated in the cathode-grid gap and inside the hollow anode. The results of the simulations show that there is no energy exchange between the beam and plasma electrons at low emission currents. For increasing current, however, we observe the increasing coupling between the electron beam and the thermal plasma electrons. This leads to the heating of plasma electrons and the generation of the so-called supra-thermal electrons.

  6. Oblique propagation of electron thermal modes below the electron plasma frequency without boundary effects

    International Nuclear Information System (INIS)

    Ohnuma, T.; Watanabe, T.; Sanuki, H.

    1981-08-01

    Propagation characteristics and refractive effects of an oblique electron thermal mode without boundary effects below the electron plasma frequency are studied experimentally and theoretically in an inhomogeneous magnetized plasma. The behavior of this mode observed experimentally was confirmed by the theoretical analysis based on a new type of ray theory. (author)

  7. Heat transfer for plasma facing components

    International Nuclear Information System (INIS)

    Boyd, R.D.; Meng, X.; Maughan, H.

    1995-01-01

    Although the high heat flux requirements for plasma-facing components have been reduced drastically from 40.0 MW/m 2 to near 10.0 MW/m 2 , there are still some refinements needed. This paper highlights: (1) recent accomplishments and pinpoints new thermal solutions and problem areas of immediate concern to the development of plasma-facing components, and (2) next generation thermal hydraulic problems which must be addressed to insure safety and reliability in component operation. More specifically the near-term thermal hydraulic problems entail: (1) generating an appropriate data base to insure the development of single-side heat flux correlations; and (2) adapting the existing vast uniform heat flux literature to the case of non-uniform heat flux distributions found in plasma facing components in fusion reactors. Results are presented for the latter task which includes: (a) an accurate subcooled flow boiling curve correlation for the partial nucleate boiling regime which can be adapted using previously proposed correlations relating single-side boundary heat flux to heat transfer, in uniformly heated channels, (b) the evaluation of the possibility of using the existing literature directly with redefined parameters, and (c) an estimation of circumferential variations in the heat transfer coefficient

  8. Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

    Energy Technology Data Exchange (ETDEWEB)

    Lu, X., E-mail: luxinpei@hotmail.com [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Naidis, G.V. [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Laroussi, M. [Plasma Engineering & Medicine Institute, Old Dominion University, Norfolk, VA 23529 (United States); Reuter, S. [Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Strasse 2, 17489 Greifswald (Germany); Graves, D.B. [Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720 (United States); Ostrikov, K. [Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000 (Australia); School of Physics, Chemistry, and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000 (Australia); Commonwealth Scientific and Industrial Research Organization, P.O.Box 218, Lindfield, NSW 2070 (Australia); School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia)

    2016-05-04

    Non-equilibrium atmospheric-pressure plasmas have recently become a topical area of research owing to their diverse applications in health care and medicine, environmental remediation and pollution control, materials processing, electrochemistry, nanotechnology and other fields. This review focuses on the reactive electrons and ionic, atomic, molecular, and radical species that are produced in these plasmas and then transported from the point of generation to the point of interaction with the material, medium, living cells or tissues being processed. The most important mechanisms of generation and transport of the key species in the plasmas of atmospheric-pressure plasma jets and other non-equilibrium atmospheric-pressure plasmas are introduced and examined from the viewpoint of their applications in plasma hygiene and medicine and other relevant fields. Sophisticated high-precision, time-resolved plasma diagnostics approaches and techniques are presented and their applications to monitor the reactive species and plasma dynamics in the plasma jets and other discharges, both in the gas phase and during the plasma interaction with liquid media, are critically reviewed. The large amount of experimental data is supported by the theoretical models of reactive species generation and transport in the plasmas, surrounding gaseous environments, and plasma interaction with liquid media. These models are presented and their limitations are discussed. Special attention is paid to biological effects of the plasma-generated reactive oxygen and nitrogen (and some other) species in basic biological processes such as cell metabolism, proliferation, survival, etc. as well as plasma applications in bacterial inactivation, wound healing, cancer treatment and some others. Challenges and opportunities for theoretical and experimental research are discussed and the authors’ vision for the emerging convergence trends across several disciplines and application domains is presented to

  9. Method and apparatus for generating and utilizing a compound plasma configuration

    International Nuclear Information System (INIS)

    Koloc, P.M.

    1977-01-01

    A method and apparatus for generating and utilizing a compound plasma configuration is disclosed. The plasma configuration includes a central toroidal plasma with electrical currents surrounded by a generally ellipsoidal mantle of ionized particles or electrically conducting matter. The preferred methods of forming this compound plasma configuration include the steps of forming a helical ionized path in a gaseous medium and simultaneously discharging a high potential through the ionized path to produce a helical or heliform current which collapses on itself to produce a toroidal current, or generating a toroidal plasmoid, supplying magnetic energy to the plasmoid, and applying fluid pressure external to the plasmoid. The apparatus of the present invention includes a pressure chamber wherein the compound plasma configuration can be isolated or compressed by fluid or other forms of mechanical or magnetic pressure. 47 claims, 10 figures

  10. Material for electrodes of low temperature plasma generators

    Science.gov (United States)

    Caplan, Malcolm; Vinogradov, Sergel Evge'evich; Ribin, Valeri Vasil'evich; Shekalov, Valentin Ivanovich; Rutberg, Philip Grigor'evich; Safronov, Alexi Anatol'evich

    2008-12-09

    Material for electrodes of low temperature plasma generators. The material contains a porous metal matrix impregnated with a material emitting electrons. The material uses a mixture of copper and iron powders as a porous metal matrix and a Group IIIB metal component such as Y.sub.2O.sub.3 is used as a material emitting electrons at, for example, the proportion of the components, mass %: iron: 3-30; Y.sub.2O.sub.3:0.05-1; copper: the remainder. Copper provides a high level of heat conduction and electric conductance, iron decreases intensity of copper evaporation in the process of plasma creation providing increased strength and lifetime, Y.sub.2O.sub.3 provides decreasing of electronic work function and stability of arc burning. The material can be used for producing the electrodes of low temperature AC plasma generators used for destruction of liquid organic wastes, medical wastes, and municipal wastes as well as for decontamination of low level radioactive waste, the destruction of chemical weapons, warfare toxic agents, etc.

  11. Sum frequency generation for studying plasma-wall interactions

    International Nuclear Information System (INIS)

    Roke, Sylvie

    2010-01-01

    Interaction of a plasma with a surface results in chemical and physical restructuring of the surface as well as the plasma in the vicinity of the surface. Studying such a reorganization of the atoms and molecules in the surface layer requires optical tools that can penetrate the plasma environment. At the same time, surface specificity is required. Sum Frequency Generation (SFG) is an optical method that fulfills these requirements. SFG has been developed into a surface specific probe during the eighties and nineties. Nowadays SFG is routinely applied in the research of complex interfaces. In such experiments, liquid/gas, solid/gas, solid/liquid, or liquid/liquid interfaces are probed, and the chemical surface composition, orientational distribution, order and chirality can be retrieved. An application to investigate plasma-wall interactions is feasible too.

  12. Influence of Ar addition on ozone generation in a non-thermal plasma-a numerical investigation

    International Nuclear Information System (INIS)

    Chen, Hsin Liang; Lee, How Ming; Chen, Shiaw Huei; Wei, Ta Chin; Chang, Moo Been

    2010-01-01

    A numerical model based on a dielectric barrier discharge is developed in this study to investigate the influence of Ar addition on ozone generation. The simulation results show good agreement with the experimental data, confirming the validity of the numerical model. The mechanisms regarding how the Ar addition affects ozone generation are investigated with the assistance of a numerical simulation by probing into the following two questions, (1) why the ozone concentration just slightly decreases in the low specific input energy (SIE, the ratio of discharge power to gas flow rate) region even if the inlet O 2 concentration is substantially decreased and (2) why the variation of the increased rate of ozone concentration with SIE (i.e. the variation in the slope of ozone concentration versus SIE) is more significant for an O 2 /Ar mixture plasma. As SIE is relatively low, ozone decomposition through electron-impact and radical attack reactions is less significant because of low ozone concentration and gas temperature. Therefore, the ozone concentration depends mainly on the amount of oxygen atoms generated. The simulation results indicate that the amount of oxygen atoms generated per electronvolt for Ar concentrations of 0%, 10%, 30%, 50% and 80% are 0.178, 0.174, 0.169, 0.165 and 0.166, respectively, explaining why the ozone concentration does not decrease linearly with the inlet O 2 concentration in the low SIE region. On the other hand, the simulation results show that increasing Ar concentration would lead to a lower reduced field and a higher gas temperature. The former would lead to an increase in the rate constant of e + O 3 → e + O + O 2 while the latter would result in a decrease in the rate constant of O + O 2 + M → O 3 + M and an increase in that of O 3 + O → 2O 2 . The changes in the rate constants of these reactions would have a negative effect on ozone generation, which is the rationale for the second question.

  13. Finite toroidal flow generated by unstable tearing mode in a toroidal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Hao, G. Z., E-mail: haogz@swip.ac.cn; Wang, A. K.; Xu, Y. H.; He, H. D.; Xu, M.; Qu, H. P.; Peng, X. D.; Xu, J. Q.; Qiu, X. M. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Liu, Y. Q. [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Sun, Y. [Institute of Plasma Physics, Chinese Academic of Sciences, P.O. Box 1126, Hefei 230031 (China); Cui, S. Y. [School of Mathematics and Statistics Science, Ludong University, Yantai 264025 (China)

    2014-12-15

    The neoclassical toroidal plasma viscosity torque and electromagnetic torque, generated by tearing mode (TM) in a toroidal plasma, are numerically investigated using the MARS-Q code [Liu et al., Phys. Plasmas 20, 042503 (2013)]. It is found that an initially unstable tearing mode can intrinsically drive a toroidal plasma flow resulting in a steady state solution, in the absence of the external momentum input and external magnetic field perturbation. The saturated flow is in the order of 0.5%ω{sub A} at the q=2 rational surface in the considered case, with q and ω{sub A} being the safety factor and the Alfven frequency at the magnetic axis, respectively. The generation of the toroidal flow is robust, being insensitive to the given amplitude of the perturbation at initial state. On the other hand, the flow amplitude increases with increasing the plasma resistivity. Furthermore, the initially unstable tearing mode is fully stabilized by non-linear interaction with the self-generated toroidal flow.

  14. Chemically different non-thermal plasmas target distinct cell death pathways

    Czech Academy of Sciences Publication Activity Database

    Lunov, Oleg; Zablotskyy, Vitaliy A.; Churpita, Olexandr; Lunova, M.; Jirsa, M.; Dejneka, Alexandr; Kubinová, Šárka

    2017-01-01

    Roč. 7, č. 1 (2017), s. 1-17, č. článku 600. ISSN 2045-2322 Grant - others:AV ČR(CZ) Fellowship J. E. Purkyně Institutional support: RVO:68378271 Keywords : chemically different * non-thermal plasmas * target distinct cell death pathways Subject RIV: BO - Biophysics OBOR OECD: Biophysics Impact factor: 4.259, year: 2016

  15. High-Intensity High-order Harmonics Generated from Low-Density Plasma

    International Nuclear Information System (INIS)

    Ozaki, T.; Bom, L. B. Elouga; Abdul-Hadi, J.; Ganeev, R. A.; Haessler, S.; Salieres, P.

    2009-01-01

    We study the generation of high-order harmonics from lowly ionized plasma, using the 10 TW, 10 Hz laser of the Advanced Laser Light Source (ALLS). We perform detailed studies on the enhancement of a single order of the high-order harmonic spectrum generated in plasma using the fundamental and second harmonic of the ALLS beam line. We observe quasi-monochromatic harmonics for various targets, including Mn, Cr, Sn, and In. We identify most of the ionic/neutral transitions responsible for the enhancement, which all have strong oscillator strengths. We demonstrate intensity enhancements of the 13th, 17th, 29th, and 33rd harmonics from these targets using the 800 nm pump laser and varying its chirp. We also characterized the attosecond nature of such plasma harmonics, measuring attosecond pulse trains with 360 as duration for chromium plasma, using the technique of ''Reconstruction of Attosecond Beating by Interference of Two-photon Transitions''(RABBIT). These results show that plasma harmonics are intense source of ultrashort coherent soft x-rays.

  16. Generation of atto-second pulses on relativistic mirror plasma

    International Nuclear Information System (INIS)

    Vincenti, H.

    2012-12-01

    When an ultra intense femtosecond laser (I > 10 16 W.cm -2 ) with high contrast is focused on a solid target, the laser field at focus is high enough to completely ionize the target surface during the rising edge of the laser pulse and form a plasma. This plasma is so dense (the electron density is of the order of hundred times the critical density) that it completely reflects the incident laser beam in the specular direction: this is the so-called 'plasma mirror'. When laser intensity becomes very high, the non-linear response of the plasma mirror to the laser field periodically deforms the incident electric field leading to high harmonic generation in the reflected beam. In the temporal domain this harmonic spectrum is associated to a train of atto-second pulses. The goals of my work were to get a better comprehension of the properties of harmonic beams produced on plasma mirrors and design new methods to control theses properties, notably in order to produce isolated atto-second pulses instead of trains. Initially, we imagined and modeled the first realistic technique to generate isolated atto-second on plasma mirrors. This brand new approach is based on a totally new physical effect: 'the atto-second lighthouse effect'. Its principle consists in sending the atto-second pulses of the train in different directions and selects one of these pulses by putting a slit in the far field. Despite its simplicity, this technique is very general and applies to any high harmonic generation mechanism. Moreover, the atto-second lighthouse effect has many other applications (e.g in metrology). In particular, it paves the way to atto-second pump-probe experiments. Then, we studied the spatial properties of these harmonics, whose control and characterization are crucial if one wants to use this source in future application experiments. For instance, we need to control very precisely the harmonic beam divergence in order to achieve the atto-second lighthouse effect and get

  17. Synthesis of ZnO nanopowders by DC thermal plasma for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soo-Jung; Choi, Jinsub [Department of Chemical Engineering, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751 (Korea, Republic of); Park, Dong-Wha, E-mail: dwpark@inha.ac.kr [Department of Chemical Engineering, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751 (Korea, Republic of)

    2013-05-01

    Highlights: ► ZnO nanopowders were synthesized using DC thermal plasma process. ► Type and flow rate of reaction gas were controlled as experimental variables. ► Various morphologies were identified by changing the reaction gas. ► The photovoltaic performances were promoted by removing the unreacted precursors. ► DSSCs based on 1D nanostructure ZnO show the enhanced energy conversion efficiency. -- Abstract: Zinc oxide (ZnO) nanopowders were synthesized from commercially available micro-sized zinc powders (Aldrich Co., 98%, 10 μm) by a DC thermal plasma process at atmospheric pressure. The micro-sized zinc powders were vaporized in the plasma region, after which the plasma processing equipment was rapidly quenched, resulting in the formation of ZnO nanopowders with a size of less than 300 nm. Two different reaction gases of oxygen and carbon dioxide were used as the oxygen source and each gas flow rate was controlled as a process variable. The obtained ZnO nanopowders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). All synthesized ZnO nanopowders showed high crystalline wurtzite structures and the differences in their morphologies were strongly dependent on the operating variables. The photocurrent–voltage (J–V) curve of the ZnO nanopowders with a dye of ruthenium (II) 535 bis-TBA (N719, Solaronix) in redox electrolyte showed an overall energy conversion efficiency (η) of 2.54%, demonstrating that the application of the mass-producible ZnO nanopowders by thermal plasma processing to DSSC was feasible.

  18. First plasma experiments in Tore Supra with a new generation of high heat flux limiters for RF antennas

    International Nuclear Information System (INIS)

    Agarici, G.; Beaumont, B.; Bibet, Ph.; Bremond, S.; Bucalossi, J.; Colas, L.; Durocher, A.; Gargiulo, L.; Ladurelle, L.; Lombard, G.; Martin, G.; Mollard, P.

    2000-01-01

    During the 1997 and 1998 Tore Supra shutdown, a first set of new antenna guard limiters was installed on one of the three ion cyclotron resonance heating (ICRH) antennas of Tore Supra. This limiter, which was one of the main technological studies of the 1998 campaign, was widely experimented in real plasma conditions, thus allowing the validation in situ, for the first time, of the technology of active metal casting (AMC) for plasma facing components. The huge improvement in the thermal response of the new limiter generation, compared to the old one, is shown on plasma pulses made identical in terms of antenna position and injected RF power profile. By using the infrared cameras installed inside Tore Supra and viewing the antennas front, the power density fluxes received by the carbon fibre composite (CFC) surface of the limiter were evaluated by correlation with the heat load tests made on the electrons beam facility of CEA/Framatome

  19. Overview on Recent Developments of Bondcoats for Plasma-Sprayed Thermal Barrier Coatings

    Science.gov (United States)

    Naumenko, D.; Pillai, R.; Chyrkin, A.; Quadakkers, W. J.

    2017-12-01

    The performance of MCrAlY (M = Ni, Co) bondcoats for atmospheric plasma-sprayed thermal barrier coatings (APS-TBCs) is substantially affected by the contents of Co, Ni, Cr, and Al as well as minor additions of Y, Hf, Zr, etc., but also by manufacturing-related properties such as coating thickness, porosity, surface roughness, and oxygen content. The latter properties depend in turn on the exact technology and set of parameters used for bondcoat deposition. The well-established LPPS process competes nowadays with alternative technologies such as HVOF and APS. In addition, new technologies have been developed for bondcoats manufacturing such as high-velocity APS or a combination of HVOF and APS for application of a flashcoat. Future developments of the bondcoat systems will likely include optimization of thermal spraying methods for obtaining complex bondcoat roughness profiles required for extended APS-TBC lifetimes. Introduction of the newest generation single-crystal superalloys possessing low Cr and high Al and refractory metals (Re, Ru) contents will require definition of new bondcoat compositions and/or multilayered bondcoats to minimize interdiffusion issues. The developments of new bondcoat compositions may be substantially facilitated using thermodynamic-kinetic modeling, the vast potential of which has been demonstrated in recent years.

  20. Electromagnetic radiation from beam-plasma instabilities

    Science.gov (United States)

    Pritchett, P. L.; Dawson, J. M.

    1983-01-01

    A computer simulation is developed for the generation of electromagnetic radiation in an electron beam-plasma interaction. The plasma is treated as a two-dimensional finite system, and effects of a continuous nonrelativistic beam input are accounted for. Three momentum and three field components are included in the simulation, and an external magnetic field is excluded. EM radiation generation is possible through interaction among Langmuir oscillations, ion-acoustic waves, and the electromagnetic wave, producing radiation perpendicular to the beam. The radiation is located near the plasma frequency, and polarized with the E component parallel to the beam. The scattering of Langmuir waves caused by ion-acoustic fluctuations generates the radiation. Comparison with laboratory data for the three-wave interactions shows good agreement in terms of the radiation levels produced, which are small relative to the plasma thermal energy.

  1. Design of extraction system on grid of plasma generator electrode for pulsed electron irradiator

    International Nuclear Information System (INIS)

    Agus Purwadi; Bambang Siswanto; Lely Susita RM; Suprapto; Anjar Anggraini H; Ihwanul Azis

    2016-01-01

    It has been carried out design and study of electron extraction particularly for obtaining the electron extraction current via grid on the Plasma Generator Chamber (PGC) caused by the existence of extraction voltage U_a. Electrons of plasma surface emitted to acceleration region through emission window and then extracted acceleration by extraction voltage U_a through foil window to atmospheric region for being applied to any target. Applied extraction voltage U_a on PEI device influences the forming and energy value of electron extraction current I_e then the PGC dimension influences the product of thermal electron emission current I_e_0. It has been determinated the PGC geometry and dimension of producing electron extraction current based on arc discharge plasma current to desire on any plasma density. From the calculation yield for the value of plasma density n_e = 78 x 10"1"0 cm"-"3 and the arc discharge current Id = 80 A (pulse width τ = 100µs) used the PGC size of (80 x 20 x 40) cm"3. Emission window area of (65 x 15) cm"2 located on the low part surface of PGC is covered by a grid sheet made of stainless steel of rectangular shape and the distance of one grid hole to another is 0,25 mm each others. Current value of I_e beside depends on plasma parameters also depends on the size of grid holes. The optimum of geometry and size is rectangular with its side size of p ≈ 0,50 mm with the plasma parameters optimum (density value n_e = 10"1"6 m"-"3 and electron temperature T_e = 6 eV). From the initial experiment yields obtained that the electron extraction efficiency value α = 37,25 % on extraction voltage V = 3 kV. (author)

  2. Chemical kinetics and relaxation of non-equilibrium air plasma generated by energetic photon and electron beams

    International Nuclear Information System (INIS)

    Maulois, Melissa; Ribière, Maxime; Eichwald, Olivier; Yousfi, Mohammed; Azaïs, Bruno

    2016-01-01

    The comprehension of electromagnetic perturbations of electronic devices, due to air plasma-induced electromagnetic field, requires a thorough study on air plasma. In the aim to understand the phenomena at the origin of the formation of non-equilibrium air plasma, we simulate, using a volume average chemical kinetics model (0D model), the time evolution of a non-equilibrium air plasma generated by an energetic X-ray flash. The simulation is undertaken in synthetic air (80% N_2 and 20% O_2) at ambient temperature and atmospheric pressure. When the X-ray flash crosses the gas, non-relativistic Compton electrons (low energy) and a relativistic Compton electron beam (high energy) are simultaneously generated and interact with the gas. The considered chemical kinetics scheme involves 26 influent species (electrons, positive ions, negative ions, and neutral atoms and molecules in their ground or metastable excited states) reacting following 164 selected reactions. The kinetics model describing the plasma chemistry was coupled to the conservation equation of the electron mean energy, in order to calculate at each time step of the non-equilibrium plasma evolution, the coefficients of reactions involving electrons while the energy of the heavy species (positive and negative ions and neutral atoms and molecules) is assumed remaining close to ambient temperature. It has been shown that it is the relativistic Compton electron beam directly created by the X-ray flash which is mainly responsible for the non-equilibrium plasma formation. Indeed, the low energy electrons (i.e., the non-relativistic ones) directly ejected from molecules by Compton collisions contribute to less than 1% on the creation of electrons in the plasma. In our simulation conditions, a non-equilibrium plasma with a low electron mean energy close to 1 eV and a concentration of charged species close to 10"1"3" cm"−"3 is formed a few nanoseconds after the peak of X-ray flash intensity. 200 ns after the

  3. Time-resolved diagnostics of excimer laser-generated ablation plasmas used for pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Geohegan, D.B.

    1994-09-01

    Characteristics of laser plasmas used for pulsed laser deposition (PLD) of thin films are examined with four in situ diagnostic techniques: Optical emission spectroscopy, optical absorption spectroscopy, ion probe studies, and gated ICCD (intensified charge-coupled-device array) fast photography. These four techniques are complementary and permit simultaneous views of the transport of ions, excited states, ground state neutrals and ions, and hot particulates following KrF laser ablation of YBCO, BN, graphite and Si in vacuum and background gases. The implementation and advantages of the four techniques are first described in order to introduce the key features of laser plasmas for pulsed laser deposition. Aspects of the interaction of the ablation plume with background gases (i.e., thermalization, attenuation, shock formation) and the collision of the plasma plume with the substrate heater are then summarized. The techniques of fast ICCD photography and gated photon counting are then applied to investigate the temperature, velocity, and spatial distribution of hot particles generated during KrF ablation of YBCO, BN, Si and graphite. Finally, key features of fast imaging of the laser ablation of graphite into high pressure rare gases are presented in order to elucidate internal reflected shocks within the plume, redeposition of material on a surface, and formation of hot nanoparticles within the plume.

  4. Time-resolved diagnostics of excimer laser-generated ablation plasmas used for pulsed laser deposition

    International Nuclear Information System (INIS)

    Geohegan, D.B.

    1994-01-01

    Characteristics of laser plasmas used for pulsed laser deposition (PLD) of thin films are examined with four in situ diagnostic techniques: Optical emission spectroscopy, optical absorption spectroscopy, ion probe studies, and gated ICCD (intensified charge-coupled-device array) fast photography. These four techniques are complementary and permit simultaneous views of the transport of ions, excited states, ground state neutrals and ions, and hot particulates following KrF laser ablation of YBCO, BN, graphite and Si in vacuum and background gases. The implementation and advantages of the four techniques are first described in order to introduce the key features of laser plasmas for pulsed laser deposition. Aspects of the interaction of the ablation plume with background gases (i.e., thermalization, attenuation, shock formation) and the collision of the plasma plume with the substrate heater are then summarized. The techniques of fast ICCD photography and gated photon counting are then applied to investigate the temperature, velocity, and spatial distribution of hot particles generated during KrF ablation of YBCO, BN, Si and graphite. Finally, key features of fast imaging of the laser ablation of graphite into high pressure rare gases are presented in order to elucidate internal reflected shocks within the plume, redeposition of material on a surface, and formation of hot nanoparticles within the plume

  5. Dispersed solar thermal generation employing parabolic dish-electric transport with field modulated generator systems

    Science.gov (United States)

    Ramakumar, R.; Bahrami, K.

    1981-01-01

    This paper discusses the application of field modulated generator systems (FMGS) to dispersed solar-thermal-electric generation from a parabolic dish field with electric transport. Each solar generation unit is rated at 15 kWe and the power generated by an array of such units is electrically collected for insertion into an existing utility grid. Such an approach appears to be most suitable when the heat engine rotational speeds are high (greater than 6000 r/min) and, in particular, if they are operated in the variable speed mode and if utility-grade a.c. is required for direct insertion into the grid without an intermediate electric energy storage and reconversion system. Predictions of overall efficiencies based on conservative efficiency figures for the FMGS are in the range of 25 per cent and should be encouraging to those involved in the development of cost-effective dispersed solar thermal power systems.

  6. Low temperature synthesis of silicon quantum dots with plasma chemistry control in dual frequency non-thermal plasmas.

    Science.gov (United States)

    Sahu, Bibhuti Bhusan; Yin, Yongyi; Han, Jeon Geon; Shiratani, Masaharu

    2016-06-21

    The advanced materials process by non-thermal plasmas with a high plasma density allows the synthesis of small-to-big sized Si quantum dots by combining low-temperature deposition with superior crystalline quality in the background of an amorphous hydrogenated silicon nitride matrix. Here, we make quantum dot thin films in a reactive mixture of ammonia/silane/hydrogen utilizing dual-frequency capacitively coupled plasmas with high atomic hydrogen and nitrogen radical densities. Systematic data analysis using different film and plasma characterization tools reveals that the quantum dots with different sizes exhibit size dependent film properties, which are sensitively dependent on plasma characteristics. These films exhibit intense photoluminescence in the visible range with violet to orange colors and with narrow to broad widths (∼0.3-0.9 eV). The observed luminescence behavior can come from the quantum confinement effect, quasi-direct band-to-band recombination, and variation of atomic hydrogen and nitrogen radicals in the film growth network. The high luminescence yields in the visible range of the spectrum and size-tunable low-temperature synthesis with plasma and radical control make these quantum dot films good candidates for light emitting applications.

  7. Possible mechanism of solar noise storm generation in meter wavelength

    International Nuclear Information System (INIS)

    Genkin, L.G.; Erukhimov, L.M.; Levin, B.N.

    1989-01-01

    Fluctuation plasma mechanism of noise storm generation is proposed. The sporadic formation of density irregularities in plasma (Langmuir) turbulence region is shown to be the result of thermal stratification of plasma. The noise storm type 1 bursts in their typical parameters are like radio emission due to plasma turbulence conversion on this structures

  8. Decontamination possibilities of high-toxic wastes by means of dense plasma generators

    International Nuclear Information System (INIS)

    Rutberg, P.G.; Kolikov, V.A.; Bogomaz, A.A.; Budin, A.V.

    1997-01-01

    In present time the idea of plasma generators application for the high-toxic agents and wastes decontamination has become very urgent. It is known that chemical bonds energy of some molecules being part of these substances is so high that it is impossible to destroy them using traditional methods. Taking into account the fact that the temperature of plasma generator's arc column may be of tens eV, and its energy of hundreds kJ, one may state that any known chemical substances taken in quite large amount, may be dissociated to the atoms. In this paper simplified construction of plasma generator and technological scheme of plasmachemical installation are presented. (author)

  9. On the propagation of hydromagnetic waves in a plasma of thermal and suprathermal components

    Science.gov (United States)

    Kumar, Nagendra; Sikka, Himanshu

    2007-12-01

    The propagation of MHD waves is studied when two ideal fluids, thermal and suprathermal gases, coupled by magnetic field are moving with the steady flow velocity. The fluids move independently in a direction perpendicular to the magnetic field but gets coupled along the field. Due to the presence of flow in suprathermal and thermal fluids there appears forward and backward waves. All the forward and backward modes propagate in such a way that their rate of change of phase speed with the thermal Mach number is same. It is also found that besides the usual hydromagnetic modes there appears a suprathermal mode which propagates with faster speed. Surface waves are also examined on an interface formed with composite plasma (suprathermal and thermal gases) on one side and the other is a non-magnetized plasma. In this case, the modes obtained are two or three depending on whether the sound velocity in thermal gas is equal to or greater than the sound velocity in suprathermal gas. The results lead to the conclusion that the interaction of thermal and suprathermal components may lead to the occurrence of an additional mode called suprathermal mode whose phase velocity is higher than all the other modes.

  10. Plasma generator utilizing dielectric member for carrying microwave energy

    International Nuclear Information System (INIS)

    Aklufi, M.E.; Brock, D.W.

    1991-01-01

    This patent describes a system in which electromagnetic energy is used to generate a plasma from a gas. It comprises a reaction chamber which is evacuated to less than ambient pressure and into which the gas is introduced; and a nonconductive member for carrying the electromagnetic energy and for emitting the electromagnetic energy so that a plasma is formed from the gas

  11. Generation of nano roughness on fibrous materials by atmospheric plasma

    International Nuclear Information System (INIS)

    Kulyk, I; Scapinello, M; Stefan, M

    2012-01-01

    Atmospheric plasma technology finds novel applications in textile industry. It eliminates the usage of water and of hazard liquid chemicals, making production much more eco-friendly and economically convenient. Due to chemical effects of atmospheric plasma, it permits to optimize dyeing and laminating affinity of fabrics, as well as anti-microbial treatments. Other important applications such as increase of mechanical resistance of fiber sleeves and of yarns, anti-pilling properties of fabrics and anti-shrinking property of wool fabrics were studied in this work. These results could be attributed to the generation of nano roughness on fibers surface by atmospheric plasma. Nano roughness generation is extensively studied at different conditions. Alternative explanations for the important practical results on textile materials and discussed.

  12. Thermophysical property calculation in thermal plasmas: status, applications, and availability of basic data

    International Nuclear Information System (INIS)

    Murphy, Anthony B.

    2002-01-01

    The status of the calculation of the composition, thermodynamic properties and transport coefficients of thermal plasmas is reviewed. The availability of the required basic data, i.e., thermodynamic properties of individual species and collision integrals for pairs of species, is surveyed. The calculation of diffusion coefficients, required in mixed-gas plasmas, is discussed, and the advantages of the combined diffusion coefficient formulation are outlined. The specific application of demixing is presented. Recent work addressing the difficulties that arise in calculating the composition and transport coefficients of two-temperature plasmas is briefly reviewed. (author)

  13. Strongly coupled Coulomb systems with positive dust grains: thermal and UV-induced plasmas

    International Nuclear Information System (INIS)

    Samarian, A.A.

    2000-01-01

    Full text: A plasma containing macroscopic dust particles or grains (often referred to as a dusty or colloidal or complex plasma) has the feature that grains may be charged by electron or ion flux or by photo- or thermoelectron emission. Electron emission from a grain surface produces a positive charge; capture of electrons produces the reverse effect making the dust grains negatively charged. Most dusty plasma research is concerned with the ordered dust structures (so-called 'plasma crystal') in glow discharges. The dust grains in these experiments were found to carry a negative charge due to the higher mobility of electrons as compared to ions in the discharge plasma. In recent years, in parallel with the study of the properties of plasma crystals under discharge conditions, attempts to obtain a structure from positively charged dust grains have been made, and structure formation processes for various charging mechanisms, particularly thermoelectron emission and photoemission, have been investigated. In this paper we review the essential features of strongly coupled plasmas with positive dust grains. An ordered structure of CeO 2 grains has been experimentally observed in a combustion products jet. The grains were charged positively and suspended in the plasma flow. Their charge is about 10 3 a and the calculated value of a Coulomb coupling parameter Γ is >10, corresponding to a plasma liquid. The ordered structures of Al 2 O 3 dust grains in propellant combustion products plasma have been observed for the first time. These structures were found in the sheath boundary of condensation region. The obtained data let us estimate the value of parameter Γ =3-40, corresponding to the plasma liquid state. The possibility is studied of the formation of ordered dust grain structures in thermal plasma. The range of the required values of the coupling parameter Γ is calculated using the results of diagnostic measurements carried out in thermal plasma with grains of

  14. Improvements to thermal plants for generating energy

    International Nuclear Information System (INIS)

    Pacault, P.H.

    1975-01-01

    Said invention relates to a procedure for superheating steam intended for steam cycled thermal plants of energy production, and particularly nuclear power plants. Said procedure combines two different working modes. According to the first working mode, the live steam is taken from the steam generator, mechanically compressed and the heat is partly transferred to the working fluid. According to the second working mode the heat is taken from an auxiliary fluid heated by an independent thermal source, distinct from the principal thermal source of the plant and this heat is partly transferred to the working fluid. A combination of both working modes enables the superheating of the working fluid to be obtained before it inflows the turbine and/or between two stages of said turbine [fr

  15. High magnetic field generation for laser-plasma experiments

    International Nuclear Information System (INIS)

    Pollock, B. B.; Froula, D. H.; Davis, P. F.; Ross, J. S.; Fulkerson, S.; Bower, J.; Satariano, J.; Price, D.; Krushelnick, K.; Glenzer, S. H.

    2006-01-01

    An electromagnetic solenoid was developed to study the effect of magnetic fields on electron thermal transport in laser plasmas. The solenoid, which is driven by a pulsed power system supplying 30 kJ, achieves magnetic fields of 13 T. The field strength was measured on the solenoid axis with a magnetic probe and optical Zeeman splitting. The measurements agree well with analytical estimates. A method for optimizing the solenoid design to achieve magnetic fields exceeding 20 T is presented

  16. Advanced Thomson scattering system for high-flux linear plasma generator

    NARCIS (Netherlands)

    Meiden, van der H.J.; Lof, A.R.; Berg, van den M.A.; Brons, S.; Donné, A.J.H.; Eck, van H.J.N.; Koelman, Peter; Koppers, W.R.; Kruijt, O.G.; Naumenko, N.N.; Oyevaar, T.; Prins, P.R.; Rapp, J.; Scholten, J.; Schram, D.C.; Smeets, P.H.M.; Star, van der G.; Tugarinov, S.N.; Zeijlmans van Emmichoven, P.A.

    2012-01-01

    An advanced Thomson scattering system has been built for a linear plasma generator for plasma surface interaction studies. The Thomson scattering system is based on a Nd:YAG laser operating at the second harmonic and a detection branch featuring a high etendue (f /3) transmission grating

  17. Short-range wakefields generated in the blowout regime of plasma-wakefield acceleration

    Science.gov (United States)

    Stupakov, G.

    2018-04-01

    In the past, calculation of wakefields generated by an electron bunch propagating in a plasma has been carried out in linear approximation, where the plasma perturbation can be assumed small and plasma equations of motion linearized. This approximation breaks down in the blowout regime where a high-density electron driver expels plasma electrons from its path and creates a cavity void of electrons in its wake. In this paper, we develop a technique that allows us to calculate short-range longitudinal and transverse wakes generated by a witness bunch being accelerated inside the cavity. Our results can be used for studies of the beam loading and the hosing instability of the witness bunch in plasma-wakefield and laser-wakefield acceleration.

  18. Megagauss field generation for high-energy-density plasma science experiments

    International Nuclear Information System (INIS)

    Rovang, Dean Curtis; Struve, Kenneth William; Porter, John Larry Jr.

    2008-01-01

    There is a need to generate magnetic fields both above and below 1 megagauss (100 T) with compact generators for laser-plasma experiments in the Beamlet and Petawatt test chambers for focused research on fundamental properties of high energy density magnetic plasmas. Some of the important topics that could be addressed with such a capability are magnetic field diffusion, particle confinement, plasma instabilities, spectroscopic diagnostic development, material properties, flux compression, and alternate confinement schemes, all of which could directly support experiments on Z. This report summarizes a two-month study to develop preliminary designs of magnetic field generators for three design regimes. These are, (1) a design for a relatively low-field (10 to 50 T), compact generator for modest volumes (1 to 10 cm3), (2) a high-field (50 to 200 T) design for smaller volumes (10 to 100 mm3), and (3) an extreme field (greater than 600 T) design that uses flux compression. These designs rely on existing Sandia pulsed-power expertise and equipment, and address issues of magnetic field scaling with capacitor bank design and field inductance, vacuum interface, and trade-offs between inductance and coil designs

  19. Thermal Structure of Supra-Arcade Plasma in Two Solar Flares

    Science.gov (United States)

    Reeves, Katharine K.; Savage, Sabrina; McKenzie, David E.; Weber, Mark A.

    2012-01-01

    In this work, we use Hinode/XRT and SDO/AIA data to determine the thermal structure of supra-arcade plasma in two solar flares. The first flare is a Ml.2 flare that occurred on November 5, 2010 on the east limb. This flare was one of a series of flares from AR 11121, published in Reeves & Golub (2011). The second flare is an XI.7 flare that occurred on January 27, 2012 on the west limb. This flare exhibits visible supra-arcade downflows (SADs), where the November 2010 flare does not. For these two flares we combine XRT and AlA data to calculate DEMs of each pixel in the supra-arcade plasma, giving insight into the temperature and density structures in the fan of plasma above the post-flare arcade. We find in each case that the supra-arcade plasma is around 10 MK, and there is a marked decrease in the emission measure in the SADs. We also compare the DEMs calculated with the combined AIA/XRT dataset to those calculated using AIA alone.

  20. Numerical studies of third-harmonic generation in laser filament in air perturbed by plasma spot

    International Nuclear Information System (INIS)

    Feng Liubin; Lu Xin; Liu Xiaolong; Li Yutong; Chen Liming; Ma Jinglong; Dong Quanli; Wang Weimin; Xi Tingting; Sheng Zhengming; Zhang Jie; He Duanwei

    2012-01-01

    Third-harmonic emission from laser filament intercepted by plasma spot is studied by numerical simulations. Significant enhancement of the third-harmonic generation is obtained due to the disturbance of the additional plasma. The contribution of the pure plasma effect and the possible plasma-enhanced third-order susceptibility on the third-harmonic generation enhancement are compared. It is shown that the plasma induced cancellation of destructive interference [Y. Liu et al., Opt. Commun. 284, 4706 (2011)] of two-colored filament is the dominant mechanism of the enhancement of third-harmonic generation.

  1. High-performance flat-panel solar thermoelectric generators with high thermal concentration

    Science.gov (United States)

    Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J. Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

    2011-07-01

    The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m-2) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity.

  2. High-performance flat-panel solar thermoelectric generators with high thermal concentration.

    Science.gov (United States)

    Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

    2011-05-01

    The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m(-2)) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity. © 2011 Macmillan Publishers Limited. All rights reserved

  3. Thermal and nuclear power generation cost estimates using corporate financial statements

    International Nuclear Information System (INIS)

    Matsuo, Yuhji; Nagatomi, Yu; Murakami, Tomoko

    2012-01-01

    There are two generally accepted methods for estimating power generation costs: so-called 'model plant' method and the method using corporate financial statements. The method using corporate financial statements, though under some constraints, can provide useful information for comparing thermal and nuclear power generation costs. This study used this method for estimating thermal and nuclear power generation costs in Japan for the past five years, finding that the nuclear power generation cost remained stable at around 7 yen per kilowatt-hour (kWh) while the thermal power generation cost moved within a wide range of 9 to 12 yen/kWh in line with wild fluctuations in primary energy prices. The cost of nuclear power generation is expected to increase due to the enhancement of safety measures and accident damage compensation in the future, while there are reactor decommissioning, backend and many other costs that the financial statement-using approach cannot accurately estimate. In the future, efforts should be continued to comprehensively and accurately estimate total costs. (author)

  4. Thermal efficiency improvements - an imperative for nuclear generating stations

    International Nuclear Information System (INIS)

    Hassanien, S.; Rouse, S.

    1997-01-01

    A one and a half percent thermal performance improvement of Ontario Hydro's operating nuclear units (Bruce B, Pickering B, and Darlington) means almost 980 GWh are available to the transmission system (assuming an 80% capacity factor). This is equivalent to the energy consumption of 34,000 electrically-heated homes in Ontario, and worth more than $39 million in revenue to Ontario Hydro Nuclear Generation. Improving nuclear plant thermal efficiency improves profitability (more GWh per unit of fuel) and competitiveness (cost of unit energy), and reduces environmental impact (less spent fuel and nuclear waste). Thermal performance will naturally decrease due to the age of the units unless corrective action is taken. Most Ontario Hydro nuclear units are ten to twenty years old. Some common causes for loss of thermal efficiency are: fouling and tube plugging of steam generators, condensers, and heat exchangers; steam leaks in the condenser due to valve wear, steam trap and drain leaks; deposition, pitting, cracking, corrosion, etc., of turbine blades; inadequate feedwater metering resulting from corrosion and deposition. This paper stresses the importance of improving the nuclear units' thermal efficiency. Ontario Hydro Nuclear has demonstrated energy savings results are achievable and affordable. Between 1994 and 1996, Nuclear reduced its energy use and improved thermal efficiency by over 430,000 MWh. Efficiency improvement is not automatic - strategies are needed to be effective. This paper suggests practical strategies to systematically improve thermal efficiency. (author)

  5. Thermal Plasma Decomposition Of Nickel And Cobalt Compounds

    Directory of Open Access Journals (Sweden)

    Woch M.

    2015-06-01

    Full Text Available The paper presents the study on manufacturing of nickel and cobalt powders by thermal plasma decomposition of the carbonates of these metals. It was shown the dependence of process parameters and grain size of initial powder on the composition of final product which was ether metal powder, collected in the container as well as the nanopowder with crystallite size of 70 - 90 nm, collected on the inner wall of the reaction chamber. The occurrence of metal oxides in the final products was confirmed and discussed.

  6. Near-surface thermal characterization of plasma facing components using the 3-omega method

    International Nuclear Information System (INIS)

    Dechaumphai, Edward; Barton, Joseph L.; Tesmer, Joseph R.; Moon, Jaeyun; Wang, Yongqiang; Tynan, George R.; Doerner, Russell P.; Chen, Renkun

    2014-01-01

    Near-surface regime plays an important role in thermal management of plasma facing components in fusion reactors. Here, we applied a technique referred to as the ‘3ω’ method to measure the thermal conductivity of near-surface regimes damaged by ion irradiation. By modulating the frequency of the heating current in a micro-fabricated heater strip, the technique enables the probing of near-surface thermal properties. The technique was applied to measure the thermal conductivity of a thin ion-irradiated layer on a tungsten substrate, which was found to decrease by nearly 60% relative to pristine tungsten for a Cu ion dosage of 0.2 dpa

  7. Mueller matrix polarimetry on plasma sprayed thermal barrier coatings for porosity measurement.

    Science.gov (United States)

    Luo, David A; Barraza, Enrique T; Kudenov, Michael W

    2017-12-10

    Yttria-stabilized zirconia (YSZ) is the most widely used material for thermal plasma sprayed thermal barrier coatings (TBCs) used to protect gas turbine engine parts in demanding operation environments. The superior material properties of YSZ coatings are related to their internal porosity level. By quantifying the porosity level, tighter control on the spraying process can be achieved to produce reliable coatings. Currently, destructive measurement methods are widely used to measure the porosity level. In this paper, we describe a novel nondestructive approach that is applicable to classify the porosity level of plasma sprayed YSZ TBCs via Mueller matrix polarimetry. A rotating retarder Mueller matrix polarimeter was used to measure the polarization properties of the plasma sprayed YSZ coatings with different porosity levels. From these measurements, it was determined that a sample's measured depolarization ratio is dependent on the sample's surface roughness and porosity level. To this end, we correlate the depolarization ratio with the samples' surface roughness, as measured by a contact profilometer, as well as the total porosity level, in percentage measured using a micrograph and stereological analysis. With the use of this technique, a full-field and rapid measurement of porosity level can be achieved.

  8. Modelling of ion thermal transport in ergodic region of collisionless toroidal plasma

    International Nuclear Information System (INIS)

    Kanno, Ryutaro; Nunami, Masanori; Satake, Shinsuke; Ohyabu, Nobuyoshi; Takamaru, Hisanori; Okamoto, Masao

    2009-09-01

    In recent tokamak experiments it has been found that so-called diffusion theory based on the 'diffusion of magnetic field lines' overestimates the radial energy transport in the ergodic region of the collisionless plasma affected by resonant magnetic perturbations (RMPs), though the RMPs induce chaotic behavior of the magnetic field lines. The result implies that the modelling of the transport should be reconsidered for low collisionality cases. A computer simulation study of transport in the ergodic region is required for understanding fundamental properties of collisionless ergodized-plasmas, estimating the transport coefficients, and reconstructing the modelling of the transport. In this paper, we report the simulation study of thermal transport in the ergodic region under the assumption of neglecting effects of an electric field, impurities and neutrals. Because of the simulations neglecting interactions with different particle-species and saving the computational time, we treat ions (protons) in our numerical-study of the transport. We find that the thermal diffusivity in the ergodic region is extremely small compared to the one predicted by the theory of field-line diffusion and that the diffusivity depends on both the collision frequency and the strength of RMPs even for the collisionless ergodized-plasma. (author)

  9. Fast camera studies at an electron cyclotron resonance table plasma generator.

    Science.gov (United States)

    Rácz, R; Biri, S; Hajdu, P; Pálinkás, J

    2014-02-01

    A simple table-size ECR plasma generator operates in the ATOMKI without axial magnetic trap and without any particle extraction tool. Radial plasma confinement is ensured by a NdFeB hexapole. The table-top ECR is a simplified version of the 14 GHz ATOMKI-ECRIS. Plasma diagnostics experiments are planned to be performed at this device before installing the measurement setting at the "big" ECRIS. Recently, the plasma generator has been operated in pulsed RF mode in order to investigate the time evolution of the ECR plasma in two different ways. (1) The visible light radiation emitted by the plasma was investigated by the frames of a fast camera images with 1 ms temporal resolution. Since the visible light photographs are in strong correlation with the two-dimensional spatial distribution of the cold electron components of the plasma it can be important to understand better the transient processes just after the breakdown and just after the glow. (2) The time-resolved ion current on a specially shaped electrode was measured simultaneously in order to compare it with the visible light photographs. The response of the plasma was detected by changing some external setting parameters (gas pressure and microwave power) and was described in this paper.

  10. Fast camera studies at an electron cyclotron resonance table plasma generator

    International Nuclear Information System (INIS)

    Rácz, R.; Biri, S.; Hajdu, P.; Pálinkás, J.

    2014-01-01

    A simple table-size ECR plasma generator operates in the ATOMKI without axial magnetic trap and without any particle extraction tool. Radial plasma confinement is ensured by a NdFeB hexapole. The table-top ECR is a simplified version of the 14 GHz ATOMKI-ECRIS. Plasma diagnostics experiments are planned to be performed at this device before installing the measurement setting at the “big” ECRIS. Recently, the plasma generator has been operated in pulsed RF mode in order to investigate the time evolution of the ECR plasma in two different ways. (1) The visible light radiation emitted by the plasma was investigated by the frames of a fast camera images with 1 ms temporal resolution. Since the visible light photographs are in strong correlation with the two-dimensional spatial distribution of the cold electron components of the plasma it can be important to understand better the transient processes just after the breakdown and just after the glow. (2) The time-resolved ion current on a specially shaped electrode was measured simultaneously in order to compare it with the visible light photographs. The response of the plasma was detected by changing some external setting parameters (gas pressure and microwave power) and was described in this paper

  11. Fast camera studies at an electron cyclotron resonance table plasma generator

    Energy Technology Data Exchange (ETDEWEB)

    Rácz, R., E-mail: rracz@atomki.hu [Institute for Nuclear Research (ATOMKI), H-4026 Debrecen, Bem tér 18/c (Hungary); Department of Experimental Physics, University of Debrecen, H-4032 Debrecen, Egyetem tér 1 (Hungary); Biri, S. [Institute for Nuclear Research (ATOMKI), H-4026 Debrecen, Bem tér 18/c (Hungary); Hajdu, P.; Pálinkás, J. [Department of Experimental Physics, University of Debrecen, H-4032 Debrecen, Egyetem tér 1 (Hungary)

    2014-02-15

    A simple table-size ECR plasma generator operates in the ATOMKI without axial magnetic trap and without any particle extraction tool. Radial plasma confinement is ensured by a NdFeB hexapole. The table-top ECR is a simplified version of the 14 GHz ATOMKI-ECRIS. Plasma diagnostics experiments are planned to be performed at this device before installing the measurement setting at the “big” ECRIS. Recently, the plasma generator has been operated in pulsed RF mode in order to investigate the time evolution of the ECR plasma in two different ways. (1) The visible light radiation emitted by the plasma was investigated by the frames of a fast camera images with 1 ms temporal resolution. Since the visible light photographs are in strong correlation with the two-dimensional spatial distribution of the cold electron components of the plasma it can be important to understand better the transient processes just after the breakdown and just after the glow. (2) The time-resolved ion current on a specially shaped electrode was measured simultaneously in order to compare it with the visible light photographs. The response of the plasma was detected by changing some external setting parameters (gas pressure and microwave power) and was described in this paper.

  12. Paracetamol degradation in aqueous solution by non-thermal plasma

    Science.gov (United States)

    Baloul, Yasmine; Aubry, Olivier; Rabat, Hervé; Colas, Cyril; Maunit, Benoît; Hong, Dunpin

    2017-08-01

    This study deals with paracetamol degradation in water using a non-thermal plasma (NTP) created by a dielectric barrier discharge (DBD). The effects of the NTP operating conditions on the degradation were studied, showing that the treatment efficiency of the process was highly dependent on the electrical parameters and working gas composition in the reactor containing the aqueous solution. A conversion rate higher than 99% was reached with an energy yield of 12 g/kWh. High resolution mass spectrometry (HRMS) measurements showed that the main species produced in water during the process were nitrogen compounds, carboxylic acids and aromatic compounds. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

  13. Research on electric and thermal characteristics of plasma torch based on similarity theory

    International Nuclear Information System (INIS)

    Cheng Changming; Tang Deli; Lan Wei

    2007-01-01

    Configuration and working principle of a DC non-transferred plasma torch have been introduced. Based on similarity theory, connections between the electric-thermal characteristics and operational parameter such as flowing gas rate and arc power have been investigated. Calculation and experiment are compared. The results indicate that the calculation results are in agreement with experimental ones. The formulas can be used for plasma torch improvement and optimization. (authors)

  14. Modeling of the plasma generated in a rarefied hypersonic shock layer

    International Nuclear Information System (INIS)

    Farbar, Erin D.; Boyd, Iain D.

    2010-01-01

    In this study, a rigorous numerical model is developed to simulate the plasma generated in a rarefied, hypersonic shock layer. The model uses the direct simulation Monte Carlo (DSMC) method to treat the particle collisions and the particle-in-cell (PIC) method to simulate the plasma dynamics in a self-consistent manner. The model is applied to compute the flow along the stagnation streamline in front of a blunt body reentering the Earth's atmosphere at very high velocity. Results from the rigorous DSMC-PIC model are compared directly to the standard DSMC modeling approach that uses the ambipolar diffusion approximation to simulate the plasma dynamics. It is demonstrated that the self-consistent computation of the plasma dynamics using the rigorous DSMC-PIC model captures many physical phenomena not accurately predicted by the standard modeling approach. These computations represent the first assessment of the validity of the ambipolar diffusion approximation when predicting the rarefied plasma generated in a hypersonic shock layer.

  15. EDITORIAL: Plasma jets and plasma bullets Plasma jets and plasma bullets

    Science.gov (United States)

    Kong, M. G.; Ganguly, B. N.; Hicks, R. F.

    2012-06-01

    Plasma plumes, or plasma jets, belong to a large family of gas discharges whereby the discharge plasma is extended beyond the plasma generation region into the surrounding ambience, either by a field (e.g. electromagnetic, convective gas flow, or shock wave) or a gradient of a directionless physical quantity (e.g. particle density, pressure, or temperature). This physical extension of a plasma plume gives rise to a strong interaction with its surrounding environment, and the interaction alters the properties of both the plasma and the environment, often in a nonlinear and dynamic fashion. The plasma is therefore not confined by defined physical walls, thus extending opportunities for material treatment applications as well as bringing in new challenges in science and technology associated with complex open-boundary problems. Some of the most common examples may be found in dense plasmas with very high dissipation of externally supplied energy (e.g. in electrical, optical or thermal forms) and often in or close to thermal equilibrium. For these dense plasmas, their characteristics are determined predominantly by strong physical forces of different fields, such as electrical, magnetic, thermal, shock wave, and their nonlinear interactions [1]. Common to these dense plasma plumes are significant macroscopic plasma movement and considerable decomposition of solid materials (e.g. vaporization). Their applications are numerous and include detection of elemental traces, synthesis of high-temperature materials and welding, laser--plasma interactions, and relativistic jets in particle accelerators and in space [2]-[4]. Scientific challenges in the understanding of plasma jets are exciting and multidisciplinary, involving interweaving transitions of all four states of matter, and their technological applications are wide-ranging and growing rapidly. Using the Web of Science database, a search for journal papers on non-fusion plasma jets reveals that a long initial phase up

  16. Optimized functionally graded La{sub 2}Zr{sub 2}O{sub 7}/8YSZ thermal barrier coatings fabricated by suspension plasma spraying

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chaohui [Laboratory of Nano Surface Engineering, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Wang, You, E-mail: wangyou@hit.edu.cn [Laboratory of Nano Surface Engineering, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Fan, Shan; You, Yuan [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Wang, Liang [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201899 (China); Yang, Changlong [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Sun, Xiaoguang [National Engineering Research Center for High-speed EMU, CSR Qingdao Sifang Co. Ltd., Qingdao 266111 (China); Li, Xuewei [Laboratory of Nano Surface Engineering, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-11-15

    In this paper, an optimized functionally graded coating (OFGC) was successfully fabricated by suspension plasma spraying (SPS) with feedstocks of the suspension of nanoparticles. La{sub 2}Zr{sub 2}O{sub 7}/8YSZ OFGC with gradual compositional variation along the through-thickness direction is proposed to mitigate spallation and crack formation owing to the high residual stresses caused by frequent thermal cycling for TBCs. The single ceramic layer coatings (SCLC) of LZ and double ceramic layer coatings (DCLC) of LZ/8YSZ were fabricated by SPS as comparison. The phase composition and microstructure of the SCLC, OFGC and DCLC were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS). Moreover, the thermal cycling tests were carried out to evaluate their thermal shock behavior. Changes in weight and morphology of specimens were analyzed during thermal cycling tests. The results showed that OFGC has extended lifetime compared with SCLC and DCLC. The failure of DCLC with clear interface between different ceramic layers occurred via delamination mode, as a result of crack initiation and propagation generated by thermal mismatch between LZ and 8YSZ. While the failure of OFGC occurred in thermally grown oxide (TGO) layers, indicating that the gradual compositional variation avoided thermal stress concentration in the top ceramic layers. - Highlights: • Optimized functionally graded coatings and double ceramic layer coatings were deposited by suspension plasma spray. • The graded area of OFGC is continuously changed from inner 8YSZ to outer La{sub 2}Zr{sub 2}O{sub 7} (LZ). • The OFGC shows a more extended thermal cycling life than the LZ SCLC and LZ/8YSZ DCLC. • Various failure mechanisms were proposed to explain thermal cycling behavior.

  17. Transfer anisotropy in a turbulent plasma

    International Nuclear Information System (INIS)

    Bychenkov, V.Y.; Gradov, O.M.; Silin, V.P.

    1982-01-01

    We formulate a theory for transfer phenomena in a plasma with developed ion-sound turbulence. A transfer anisotropy effect caused by a temperature gradient is revealed. The corresponding fluxes transverse to the effective force vector (1) which generates the turbulence turn out to be considerably larger than the longitudinal fluxes in a plasma with a relatively small degree of nonisothermality. For a strongly nonisothermal plasma a suppression of the transverse fluxes takes place and corresponds to a growth of the thermal insulation of the current-carrying plasma filaments

  18. Spatial diagnostics of the laser induced lithium fluoride plasma

    Energy Technology Data Exchange (ETDEWEB)

    Baig, M. A.; Qamar, Aisha; Fareed, M. A.; Anwar-ul-Haq, M.; Ali, Raheel [Atomic and Molecular Physics Laboratory, Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan)

    2012-06-15

    We present spatial characteristics of the lithium fluoride plasma generated by the fundamental and second harmonic of a Nd:YAG laser. The plume emission has been recorded spatially using five spectrometers covering the spectral region from 200 nm to 720 nm. The electron density is measured from the Stark broadened line profile of the line at 610.37 nm, whereas the plasma temperature has been determined using the Boltzmann plot method including all the observed spectral lines of lithium. Both the plasma parameters; electron density and plasma temperature decrease with the increase of the distance from the target surface. The thermal conduction towards the target, the radiative cooling of the plasma, and the conversion of thermal energy into kinetic energy are the main mechanisms responsible for the spatially decrease of the plasma parameters.

  19. THERMAL TEXTURE GENERATION AND 3D MODEL RECONSTRUCTION USING SFM AND GAN

    Directory of Open Access Journals (Sweden)

    V. V. Kniaz

    2018-05-01

    Full Text Available Realistic 3D models with textures representing thermal emission of the object are widely used in such fields as dynamic scene analysis, autonomous driving, and video surveillance. Structure from Motion (SfM methods provide a robust approach for the generation of textured 3D models in the visible range. Still, automatic generation of 3D models from the infrared imagery is challenging due to an absence of the feature points and low sensor resolution. Recent advances in Generative Adversarial Networks (GAN have proved that they can perform complex image-to-image transformations such as a transformation of day to night and generation of imagery in a different spectral range. In this paper, we propose a novel method for generation of realistic 3D models with thermal textures using the SfM pipeline and GAN. The proposed method uses visible range images as an input. The images are processed in two ways. Firstly, they are used for point matching and dense point cloud generation. Secondly, the images are fed into a GAN that performs the transformation from the visible range to the thermal range. We evaluate the proposed method using real infrared imagery captured with a FLIR ONE PRO camera. We generated a dataset with 2000 pairs of real images captured in thermal and visible range. The dataset is used to train the GAN network and to generate 3D models using SfM. The evaluation of the generated 3D models and infrared textures proved that they are similar to the ground truth model in both thermal emissivity and geometrical shape.

  20. Oxidation and thermal shock behavior of thermal barrier coated 18/10CrNi alloy with coating modifications

    Energy Technology Data Exchange (ETDEWEB)

    Guergen, Selim [Vocational School of Transportation, Anadolu University, Eskisehir (Turkmenistan); Diltemiz, Seyid Fehmi [Turkish Air Force1st Air Supply and Maintenance Center Command, Eskisehir (Turkmenistan); Kushan, Melih Cemal [Dept. of Mechanical Engineering, Eskisehir Osmangazi University, Eskisehir (Turkmenistan)

    2017-01-15

    In this study, substrates of 18/10CrNi alloy plates were initially sprayed with a Ni-21Cr-10Al-1Y bond coat and then with an yttria stabilized zirconia top coat by plasma spraying. Subsequently, plasma-sprayed Thermal barrier coatings (TBCs) were treated with two different modification methods, namely, vacuum heat treatment and laser glazing. The effects of modifications on the oxidation and thermal shock behavior of the coatings were evaluated. The effect of coat thickness on the bond strength of the coats was also investigated. Results showed enhancement of the oxidation resistance and thermal shock resistance of TBCs following modifications. Although vacuum heat treatment and laser glazing exhibited comparable results as per oxidation resistance, the former generated the best improvement in the thermal shock resistance of the TBCs. Bond strength also decreased as coat thickness increased.

  1. The theta-pinch - a versatile tool for the generation and study of high temperature plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Hintz, E. [Inst. fuer Plasmaphysik, Forschungszentrum-Juelich GmbH (Germany)

    2004-07-01

    The more general technical and physical features of theta-pinches are described. Special field of their application are high-ss plasmas. Two examples are analysed and studied in more detail: a high density plasma near thermal equilibrium and a low density plasma far from equilibrium. The latter is of special interest for future investigations. Possibilities of field-reversed configurations are pointed out. (orig.)

  2. The theta-pinch - a versatile tool for the generation and study of high temperature plasmas

    International Nuclear Information System (INIS)

    Hintz, E.

    2004-01-01

    The more general technical and physical features of theta-pinches are described. Special field of their application are high-ss plasmas. Two examples are analysed and studied in more detail: a high density plasma near thermal equilibrium and a low density plasma far from equilibrium. The latter is of special interest for future investigations. Possibilities of field-reversed configurations are pointed out. (orig.)

  3. Electromagnetic radiation generated by arcing in low density plasma

    Science.gov (United States)

    Vayner, Boris V.; Ferguson, Dale C.; Snyder, David B.; Doreswamy, C. V.

    1996-01-01

    An unavoidable step in the process of space exploration is to use high-power, very large spacecraft launched into Earth orbit. Obviously, the spacecraft will need powerful energy sources. Previous experience has shown that electrical discharges occur on the surfaces of a high-voltage array, and these discharges (arcs) are undesirable in many respects. Moreover, any high voltage conductor will interact with the surrounding plasma, and that interaction may result in electrical discharges between the conductor and plasma (or between two conductors with different potentials, for example, during docking and extravehicular activity). One very important aspect is the generation of electromagnetic radiation by arcing. To prevent the negative influence of electromagnetic noise on the operation of spacecraft systems, it seems necessary to determine the spectra and absolute levels of the radiation, and to determine limitations on the solar array bias voltage that depend on the parameters of LEO plasma and the technical requirements of the spacecraft equipment. This report describes the results of an experimental study and computer simulation of the electromagnetic radiation generated by arcing on spacecraft surfaces. A large set of high quality data was obtained during the Solar Array Module Plasma Interaction Experiment (SAMPIE, flight STS-62) and ground test. These data include the amplitudes of current, pulse forms, duration of each arc, and spectra of plasma waves. A theoretical explanation of the observed features is presented in this report too. The elaborated model allows us to determine the parameters of the electromagnetic noise for different frequency ranges, distances from the arcing site, and distinct kinds of plasma waves.

  4. Influence of winding construction on starter-generator thermal processes

    Science.gov (United States)

    Grachev, P. Yu; Bazarov, A. A.; Tabachinskiy, A. S.

    2018-01-01

    Dynamic processes in starter-generators features high winding are overcurrent. It can lead to insulation overheating and fault operation mode. For hybrid and electric vehicles, new high efficiency construction of induction machines windings is proposed. Stator thermal processes need be considered in the most difficult operation modes. The article describes construction features of new compact stator windings, electromagnetic and thermal models of processes in stator windings and explains the influence of innovative construction on thermal processes. Models are based on finite element method.

  5. Runaway electron generation in tokamak disruptions

    International Nuclear Information System (INIS)

    Helander, P.; Andersson, F.; Fueloep, T.; Smith, H.; Anderson, D.; Lisak, M.; Eriksson, L.-G.

    2005-01-01

    The time evolution of the plasma current during a tokamak disruption is calculated by solving the equations for runaway electron production simultaneously with the induction equation for the toroidal electric field. The resistive diffusion time in a post-disruption plasma is typically comparable to the runaway avalanche growth time. Accordingly, the toroidal electric field induced after the thermal quench of a disruption diffuses radially through the plasma at the same time as it accelerates runaway electrons, which in turn back-react on the electric field. When these processes are accounted for in a self-consistent way, it is found that (1) the efficiency and time scale of runaway generation agrees with JET experiments; (2) the runaway current profile typically becomes more peaked than the pre-disruption current profile; and (3) can easily become radially filamented. It is also shown that higher runaway electron generation is expected if the thermal quench is sufficiently fast. (author)

  6. Plasma fluorination of vertically aligned carbon nanotubes: functionalization and thermal stability.

    Science.gov (United States)

    Struzzi, Claudia; Scardamaglia, Mattia; Hemberg, Axel; Petaccia, Luca; Colomer, Jean-François; Snyders, Rony; Bittencourt, Carla

    2015-01-01

    Grafting of fluorine species on carbon nanostructures has attracted interest due to the effective modification of physical and chemical properties of the starting materials. Various techniques have been employed to achieve a controlled fluorination yield; however, the effect of contaminants is rarely discussed, although they are often present. In the present work, the fluorination of vertically aligned multiwalled carbon nanotubes was performed using plasma treatment in a magnetron sputtering chamber with fluorine diluted in an argon atmosphere with an Ar/F2 ratio of 95:5. The effect of heavily diluted fluorine in the precursor gas mixture is investigated by evaluating the modifications in the nanotube structure and the electronic properties upon plasma treatment. The existence of oxygen-based grafted species is associated with background oxygen species present in the plasma chamber in addition to fluorine. The thermal stability and desorption process of the fluorine species grafted on the carbon nanotubes during the fluorine plasma treatment were evaluated by combining different spectroscopic techniques.

  7. Plasma fluorination of vertically aligned carbon nanotubes: functionalization and thermal stability

    Directory of Open Access Journals (Sweden)

    Claudia Struzzi

    2015-12-01

    Full Text Available Grafting of fluorine species on carbon nanostructures has attracted interest due to the effective modification of physical and chemical properties of the starting materials. Various techniques have been employed to achieve a controlled fluorination yield; however, the effect of contaminants is rarely discussed, although they are often present. In the present work, the fluorination of vertically aligned multiwalled carbon nanotubes was performed using plasma treatment in a magnetron sputtering chamber with fluorine diluted in an argon atmosphere with an Ar/F2 ratio of 95:5. The effect of heavily diluted fluorine in the precursor gas mixture is investigated by evaluating the modifications in the nanotube structure and the electronic properties upon plasma treatment. The existence of oxygen-based grafted species is associated with background oxygen species present in the plasma chamber in addition to fluorine. The thermal stability and desorption process of the fluorine species grafted on the carbon nanotubes during the fluorine plasma treatment were evaluated by combining different spectroscopic techniques.

  8. Characterization of X-ray emission from laser generated plasma

    Science.gov (United States)

    Cannavò, Antonino; Torrisi, Lorenzo; Ceccio, Giovanni; Cutroneo, Mariapompea; Calcagno, Lucia; Sciuto, Antonella; Mazzillo, Massimo

    2018-01-01

    X-ray emission from laser generated plasma was studied at low (1010 W/cm2) and high (1018 W/cm2) intensity using ns and fs laser, respectively. Plasma characteristics were controlled trough the laser parameters, the irradiation conditions and the target properties. The X-ray spectra were acquired using fast detection technique based on SiC diodes with different active regions. The X-ray yield increases with the atomic number of the target, both at low and high intensity, and a similar empirical law has been obtained. The X-ray emission mechanisms from plasma are correlated to the plasma temperature and density and to the Coulomb charge particle acceleration, due to the charge separation effects produced in the non-equilibrium plasma. Functional dependences, theoretical approaches and interpretation of possible mechanism will be presented and discussed.

  9. Characterization of X-ray emission from laser generated plasma

    Directory of Open Access Journals (Sweden)

    Cannavò Antonino

    2018-01-01

    Full Text Available X-ray emission from laser generated plasma was studied at low (1010 W/cm2 and high (1018 W/cm2 intensity using ns and fs laser, respectively. Plasma characteristics were controlled trough the laser parameters, the irradiation conditions and the target properties. The X-ray spectra were acquired using fast detection technique based on SiC diodes with different active regions. The X-ray yield increases with the atomic number of the target, both at low and high intensity, and a similar empirical law has been obtained. The X-ray emission mechanisms from plasma are correlated to the plasma temperature and density and to the Coulomb charge particle acceleration, due to the charge separation effects produced in the non-equilibrium plasma. Functional dependences, theoretical approaches and interpretation of possible mechanism will be presented and discussed.

  10. Thermal loads on tokamak plasma-facing components during normal operation and disruptions

    International Nuclear Information System (INIS)

    McGrath, R.T.

    1990-01-01

    Power loadings experienced by tokamak plasma-facing components during normal operation and during off-normal events are discussed. A model for power and particle flow in the tokamak boundary layer is presented and model predictions are compared to infrared measurements of component heating. The inclusion of the full three-dimensional geometry of the components and of the magnetic flux surface is very important in the modeling. Experimental measurements show that misalignment of component armour tile surfaces by only a millimeter can lead to significant localized heating. An application to the design of plasma-facing components for future machines is presented. Finally, thermal loads expected during tokamak disruptions are discussed. The primary problems are surface melting and vaporization due to localized intense heating during the disruption thermal quench and volumetric heating of the component armour and structure due to localised impact of runaway electrons. (author)

  11. Dense strongly non-ideal plasma generation by laser isobaric heating

    International Nuclear Information System (INIS)

    Kulik, P.P.; Rozanov, E.K.; Riabii, V.A.; Titov, M.A.

    1975-01-01

    A method of generation of a dense strongly non-ideal plasma by slow isobaric heating of a small target in a high inert gas medium is discussed. The characteristic life-time of dense plasma is 10 -3 sec. Estimations show that such a plasma is homogeneous. Conditions are found for temperature uniformity. The experimental results of the isobaric heating of a thin potassium foil target by a ruby laser beam at 500 atm are described. (Auth.)

  12. Electromagnetic-implosion generation of pulsed high energy density plasma

    International Nuclear Information System (INIS)

    Baker, W.L.; Broderick, N.F.; Degnan, J.H.; Hussey, T.W.; Kiuttu, G.F.; Kloc, D.A.; Reinovsky, R.E.

    1983-01-01

    This chapter reports on the experimental and theoretical investigation of the generation of pulsed high-energy-density plasmas by electromagnetic implosion of cylindrical foils (i.e., imploding liners or hollow Z-pinches) at the Air Force Weapons Laboratory. Presents a comparison of experimental data with one-dimensional MHD and two-dimensional calculations. Points out that the study is distinct from other imploding liner efforts in that the approach is to produce a hot, dense plasma from the imploded liner itself, rather than to compress a magnetic-field-performed plasma mixture. The goal is to produce an intense laboratory pulsed X-ray source

  13. Pulsed x-ray generation from a plasma focus device

    International Nuclear Information System (INIS)

    Zambra, M; Bruzzone, H; Sidelnikov, Y; Kies, W; Moreno, C; Sylvester, G; Silva, P; Moreno, J; Soto, L

    2003-01-01

    Dynamical pinches coupled to electrodes like the dense Z-pinch or the dense plasma focus have been intensively studied in the last four decades for their high fusion efficiency and their application potential. Though the expectations of the eighties of the last century, scaling these pinches up to fusion reactors, did not come true, the development of fast and powerful experiments resulted in new insights in pinch physics and paved the way for developing compact dynamical pinches as pulsed neutron and X-radiation sources for many applications. There is a permanent and growing interest in the research community for understanding and determining the generation properties of X-rays, neutrons and charged particles emitted from a high-temperature high-density plasmas, especially in the plasma focus configuration. The Plasma Physics and Plasma Technology Group of the CCHEN has developed the SPEED4 fast-plasma focus device, in collaboration with the Plasma Physics Group of the Dusseldorf University, in order to perform experimental studies such as X-ray and neutron emission, and electron and ion beam characterization (author)

  14. Impact of plasma jet vacuum ultraviolet radiation on reactive oxygen species generation in bio-relevant liquids

    Energy Technology Data Exchange (ETDEWEB)

    Jablonowski, H.; Hammer, M. U.; Reuter, S. [Center for Innovation Competence plasmatis, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V. Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Bussiahn, R.; Weltmann, K.-D.; Woedtke, Th. von [Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V. Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)

    2015-12-15

    Plasma medicine utilizes the combined interaction of plasma produced reactive components. These are reactive atoms, molecules, ions, metastable species, and radiation. Here, ultraviolet (UV, 100–400 nm) and, in particular, vacuum ultraviolet (VUV, 10–200 nm) radiation generated by an atmospheric pressure argon plasma jet were investigated regarding plasma emission, absorption in a humidified atmosphere and in solutions relevant for plasma medicine. The energy absorption was obtained for simple solutions like distilled water (dH{sub 2}O) or ultrapure water and sodium chloride (NaCl) solution as well as for more complex ones, for example, Rosewell Park Memorial Institute (RPMI 1640) cell culture media. As moderate stable reactive oxygen species, hydrogen peroxide (H{sub 2}O{sub 2}) was studied. Highly reactive oxygen radicals, namely, superoxide anion (O{sub 2}{sup •−}) and hydroxyl radicals ({sup •}OH), were investigated by the use of electron paramagnetic resonance spectroscopy. All species amounts were detected for three different treatment cases: Plasma jet generated VUV and UV radiation, plasma jet generated UV radiation without VUV part, and complete plasma jet including all reactive components additionally to VUV and UV radiation. It was found that a considerable amount of radicals are generated by the plasma generated photoemission. From the experiments, estimation on the low hazard potential of plasma generated VUV radiation is discussed.

  15. Chemical and physical reactions under thermal plasmas conditions

    International Nuclear Information System (INIS)

    Fauchais, P.; Vardelle, A.; Vardelle, M.; Coudert, J.F.

    1987-01-01

    Basic understanding of the involved phenomena lags far behind industrial development that requires now a better knowledge of the phenomena to achieve a better control of the process allowing to improve the quality of the products. Thus the authors try to precise what is their actual knowledge in the fields of: plasma generators design; plasma flow models with the following key points: laminar or turbulent flow, heat transfer to walls, 2D or 3D models, non equilibrium effects, mixing problems when chemical reactions are to be taken into account with very fast kinetics, electrode regions, data for transport properties and kinetic rates; nucleation problems; plasma flow characteristics measurements: temperature or temperatures and population of excited states (automatized emission spectroscopy, LIF, CARS) as well as flow velocity (LDA with small particles, Doppler effects...); plasma and particles momentum and heat transfer either with models taking into account particles size and injection velocity distributions, heat propagation, vaporization, Kundsen effect, turbulences ... or with measurements: particles velocity and flux distributions (Laser Anemometry) as well as surface temperature distributions (two colour pyrometry in flight statistical or not)

  16. IAEA consultants' meeting on thermal response of plasma facing materials and components

    International Nuclear Information System (INIS)

    Janev, R.K.

    1990-07-01

    The present Summary Report contains brief proceedings and the main conclusions and recommendations of the IAEA Consultants' Meeting on ''Thermal Response of Plasma Facing Materials and Components'', which was organized by the IAEA Atomic and Molecular Data Unit and held on June 11-13, 1990, in Vienna, Austria. The Report also includes a categorization and assessment of currently studied plasma facing materials, a classification scheme of material properties data, required in fusion reactor design, and a survey of the urgently needed material properties data. (author)

  17. Study by X-ray diffraction and mechanical analysis of the residual stress generation during thermal spraying

    International Nuclear Information System (INIS)

    Pina, J.; Dias, A.; Lebrun, J.L.

    2003-01-01

    Thermally sprayed coatings are formed by the deposition of molten or partially molten particles, propelled onto a substrate where they impact, spread and solidify rapidly. Residual stresses are expected within the sprayed deposit as a consequence of the release of thermal and kinetic energies. A wide range of materials and two spraying techniques are considered in this study, namely atmospheric plasma spraying (APS) and high-velocity oxygen fuel. Stresses were determined by the X-ray diffraction (XRD) method. The results were compared with those calculated by mechanical analysis of stress relief in coatings detached from the substrate. Comparison of the results for adherent and free-standing coatings shows that the residual stress state can be resolved in terms of the components suggested by models that propose two stages of stress generation: quenching stresses and secondary-cooling stresses. The in-depth distribution of residual stresses, through the coating thickness, is discussed in terms of the nature of the coating system

  18. Catastrophe in plasma focus evolution

    International Nuclear Information System (INIS)

    Ikuta, Kazunari.

    1984-07-01

    A theory of generating strong electric field in a dense plasma column in plasma focus is established by applying the formula for the electron thermal conductivity in destroyed magnetic surfaces like those in tokamaks. The origin of the electric field may be from abrupt rise of plasma resistivity when the irregularity of magnetic field is weak. However, the electric field can be from the inductive origin in case the irregularity attains a certain level. Both origin should be mixed up depending on the magnitude of the irregularity. (author)

  19. Understanding CO2 decomposition by thermal plasma with supersonic expansion quench

    Science.gov (United States)

    Tao, YANG; Jun, SHEN; Tangchun, RAN; Jiao, LI; Pan, CHEN; Yongxiang, YIN

    2018-04-01

    CO2 pyrolysis by thermal plasma was investigated, and a high conversion rate of 33% and energy efficiency of 17% were obtained. The high performance benefited from a novel quenching method, which synergizes the converging nozzle and cooling tube. To understand the synergy effect, a computational fluid dynamics simulation was carried out. A quick quenching rate of 107 K s‑1 could be expected when the pyrolysis gas temperature decreased from more than 3000 to 1000 K. According to the simulation results, the quenching mechanism was discussed as follows: first, the compressible fluid was adiabatically expanded in the converging nozzle and accelerated to sonic speed, and parts of the heat energy converted to convective kinetic energy; second, the sonic fluid jet into the cooling tube formed a strong eddy, which greatly enhanced the heat transfer between the inverse-flowing fluid and cooling tube. These two mechanisms ensure a quick quenching to prevent the reverse reaction of CO2 pyrolysis gas when it flows out from the thermal plasma reactor.

  20. Beam-plasma generators of stochastic microwave oscillations using for plasma heating in fusion and plasma-chemistry devices and ionospheric investigations

    Energy Technology Data Exchange (ETDEWEB)

    Mitin, L A; Perevodchikov, V I; Shapiro, A L; Zavyalov, M A [All-Russian Electrotechnical Inst., Moscow (Russian Federation); Bliokh, Yu P; Fajnberg, Ya B [Kharkov Inst. of Physics and Technology (Russian Federation)

    1997-12-31

    The results of theoretical and experimental investigations of a generator of stochastic microwave power based on a beam-plasma inertial feedback amplifier is discussed with a view to using stochastic oscillations for plasma heating. The plasma heating efficiency in the region of low-frequency resonance in the geometry of the Tokamak is considered theoretically. It is shown that the temperature of heating is proportional to the power multiplied by the spectra width of the noiselike signal. The creation and heating of plasma by stochastic microwave power in an oversized waveguide without external magnetic field is discussed with a view to plasma-chemistry applications. It is shown that the efficiency of heating are defined by the time of phase instability of the stochastic power. (author). 3 figs., 13 refs.

  1. Electromagnetic induction phenomena in plasma systems

    International Nuclear Information System (INIS)

    Karlovitz, B.

    1982-01-01

    The phenomenon of electromagnetic induction is considered in complex high temperature plasma systems. Thermal energy of such fully ionized plasma is really energy of the magnetic vortex fields surrounding the randomly moving ions and electrons. In an expanding plasma stream, moving across the containing magnetic field, random thermal motion of the ions and electrons is converted into ordered motion and thereby random magnetic energy of the plasma into magnetic energy of an ordered field. Consequently, in contrast to simple systems consisting of coils and magnets only, an expanding plasma stream can maintain net outflow of ordered magnetic energy from a closed volume for an indefinite length of time. Conversion of thermal energy of plasma into ordered magnetic energy by the thermodynamic expansion process leads to the expectation of a new induction phenomenon: the generation of a unidirectional induced electromotive force of unlimited duration, measured in a closed loop at rest relative to the magnetic field, by the expansion work of the plasma stream. No change is required in the differential form of Maxwell's equations for the existence of this induction phenomenon, only the definition of the concept of rate of change of magnetic flux needs to be modified in the macroscopic equations to correspond to the rate of flow of magnetic energy across a closed surface. An experimental test of the predicted induction phenomenon is proposed

  2. Atmospheric-pressure plasma jet

    Science.gov (United States)

    Selwyn, Gary S.

    1999-01-01

    Atmospheric-pressure plasma jet. A .gamma.-mode, resonant-cavity plasma discharge that can be operated at atmospheric pressure and near room temperature using 13.56 MHz rf power is described. Unlike plasma torches, the discharge produces a gas-phase effluent no hotter than 250.degree. C. at an applied power of about 300 W, and shows distinct non-thermal characteristics. In the simplest design, two concentric cylindrical electrodes are employed to generate a plasma in the annular region therebetween. A "jet" of long-lived metastable and reactive species that are capable of rapidly cleaning or etching metals and other materials is generated which extends up to 8 in. beyond the open end of the electrodes. Films and coatings may also be removed by these species. Arcing is prevented in the apparatus by using gas mixtures containing He, which limits ionization, by using high flow velocities, and by properly shaping the rf-powered electrode. Because of the atmospheric pressure operation, no ions survive for a sufficiently long distance beyond the active plasma discharge to bombard a workpiece, unlike low-pressure plasma sources and conventional plasma processing methods.

  3. Investigation of non thermal effects from the Dα line wings in edge plasmas

    International Nuclear Information System (INIS)

    Marandet, Y.; Godbert-Mouret, L.; Koubiti, M.; Stamm, R.; Capes, H.; Guirlet, R.

    2002-01-01

    The far wings of intense Dα lines measured at the edge of the Tore Supra Tokamak are found to exhibit a power-law behavior. The characteristic exponent is not far from two. Since the low density rules out thermal Stark broadening, we discuss non thermal effects which may arise from the edge plasma drift-wave turbulence. We suggest that both the Stark and the Doppler profile could be affected by the turbulence

  4. Non-thermal Power-Law Distributions in Solar and Space Plasmas

    Science.gov (United States)

    Oka, M.; Battaglia, M.; Birn, J.; Chaston, C. C.; Effenberger, F.; Eriksson, E.; Fletcher, L.; Hatch, S.; Imada, S.; Khotyaintsev, Y. V.; Kuhar, M.; Livadiotis, G.; Miyoshi, Y.; Retino, A.

    2017-12-01

    Particles are accelerated to very high, non-thermal energies in solar and space plasma environments. While energy spectra of accelerated particles often exhibit a power-law and are characterized by the power-law index δ, it remains unclear how particles are accelerated to high energies and how δ is determined. Here, we review previous observations of the power-law index δ in a variety of different plasma environments with a particular focus on sub-relativistic electrons. It appears that in regions more closely related to magnetic reconnection (such as the "above-the-looptop" solar hard X-ray source and the plasma sheet in Earth's magnetotail), the spectra are typically soft (δ> 4). This is in contrast to the typically hard spectra (δuniform in the plasma sheet, while power-law distributions still exist even in quiet times. The role of magnetotail reconnection in the electron power-law formation could therefore be confounded with these background conditions. Because different regions have been studied with different instrumentations and methodologies, we point out a need for more systematic and coordinated studies of power-law distributions for a better understanding of possible scaling laws in particle acceleration as well as their universality.

  5. Plasma generated in culture medium induces damages of HeLa cells due to flow phenomena

    Science.gov (United States)

    Sato, Yusuke; Sato, Takehiko; Yoshino, Daisuke

    2018-03-01

    Plasma in a liquid has been anticipated as an effective tool for medical applications, however, few reports have described cellular responses to plasma generated in a liquid similar to biological fluids. Herein we report the effects of plasma generated in a culture medium on HeLa cells. The plasma in the culture medium produced not only heat, shock waves, and reactive chemical species but also a jet flow with sub millimeter-sized bubbles. Cells exposed to the plasma exhibited detachment, morphological changes, and changes in the actin cytoskeletal structure. The experimental results suggest that wall shear stress over 160 Pa was generated on the surface of the cells by the plasma. It is one of the main factors that cause those cellular responses. We believe that our findings would provide valuable insight into advancements in medical applications of plasma in a liquid.

  6. Atmospheric-Pressure Non-Thermal Plasma Jet for biomedical and industrial applications

    International Nuclear Information System (INIS)

    Asenjo, J; Mora, J; Vargas, A; Brenes, L; Montiel, R; Arrieta, J; Vargas, VI

    2015-01-01

    In this work we present the development and evaluation of a low-cost DBD Plasma- JET reactor using Argon as carrier gas, this device is capable of generating a cold plasma plume several centimeters in length making it suitable for use directly in contact with objects and delicate materials, including living tissue. (paper)

  7. The thermalization of soft modes in non-expanding isotropic quark gluon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Blaizot, Jean-Paul, E-mail: jean-paul.blaizot@cea.fr [Institut de Physique Théorique, CNRS/UMR 3681, CEA Saclay, F-91191 Gif-sur-Yvette (France); Liao, Jinfeng [Physics Department and Center for Exploration of Energy and Matter, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); Mehtar-Tani, Yacine [Institute for Nuclear Theory, University of Washington, Seattle, WA 98195-1550 (United States)

    2017-05-15

    We discuss the role of elastic and inelastic collisions and their interplay in the thermalization of the quark–gluon plasma. We consider a simplified situation of a static plasma, spatially uniform and isotropic in momentum space. We focus on the small momentum region, which equilibrates first, and on a short time scale. We obtain a simple kinetic equation that allows for an analytic description of the most important regimes. The present analysis suggests that the formation of a Bose condensate, expected when only elastic collisions are present, is strongly hindered by the inelastic, radiative, processes.

  8. Thermal mechanical analysis of applications with internal heat generation

    Science.gov (United States)

    Govindarajan, Srisharan Garg

    The radioactive tracer Technetium-99m is widely used in medical imaging and is derived from its parent isotope Molybedenum-99 (Mo-99) by radioactive decay. The majority of Molybdenum-99 (Mo-99) produced internationally is extracted from high enriched uranium (HEU) dispersion targets that have been irradiated. To alleviate proliferation risks associated with HEU-based targets, the use of non-HEU sources is being mandated. However, the conversion of HEU to LEU based dispersion targets affects the Mo-99 available for chemical extraction. A possible approach to increase the uranium density, to recover the loss in Mo-99 production-per-target, is to use an LEU metal foil placed within an aluminum cladding to form a composite structure. The target is expected to contain the fission products and to dissipate the generated heat to the reactor coolant. In the event of interfacial separation, an increase in the thermal resistance could lead to an unacceptable rise in the LEU temperature and stresses in the target. The target can be deemed structurally safe as long as the thermally induced stresses are within the yield strength of the cladding and welds. As with the thermal and structural safety of the annular target, the thermally induced deflection of the BORALRTM-based control blades, used by the University of Missouri Research Reactor (MURRRTM ), during reactor operation has been analyzed. The boron, which is the neutron absorber in BORAL, and aluminum mixture (BORAL meat) and the aluminum cladding are bonded together through powder metallurgy to establish an adherent bonded plate. As the BORAL absorbs both neutron particles and gamma rays, there is volumetric heat generation and a corresponding rise in temperature. Since the BORAL meat and aluminum cladding materials have different thermal expansion coefficients, the blade may have a tendency to deform as the blade temperature changes and the materials expand at different rates. In addition to the composite nature of the

  9. Destruction studies of hazardous wastes by thermal plasma; Estudios de degradacion de residuos peligrosos mediante plasma termico

    Energy Technology Data Exchange (ETDEWEB)

    Cota S, G

    1998-11-01

    Plasma technology appears promising because its high degree of controllability, capability to process waste without the adverse effects of combustion, and a very wide temperature range of operation. The goal of this work was to develop a process for a high throughput system to turn hazardous waste into inert stable products, which can be safely stored and to greatly reduce air pollution relative to incineration. The experiments have shown that the thermal plasma reactor can provide a high degree of decomposition of CCl{sub 4} , C{sub 6} H{sub 6}, C{sub 2} Cl{sub 4} and commercial oil at low gas input speeds, with modest power requirements. Decomposition of 99.9999 % has been obtained in our laboratory and all the organic components are decomposed in base molecules (C, CO, CO{sub 2}, H{sub 2}, HCl). The analysis of exhaust gases was made by using a mass filter quadrupole. The equipment consist of a cylindrical reactor hermetically sealed, double-walled and water-cooled container made of special steel, this container in halt the crucible which serves to receive the waste materials. The whole system is designed for a maximal internal temperature of 2000 Centigrade. The gaseous result components of the material are transferred to a scrubber unit through an exit arranged on the top of reactor. The thermal efficiency evaluation of the plasma torch was also realized, obtaining a reasonable agreement between measurements and predictions in temperature profiles. (Author)

  10. Characteristics of a Novel Water Plasma Torch

    International Nuclear Information System (INIS)

    Guo-Hua, Ni; Yue-Dong, Meng; Cheng, Cheng; Yan, Lan

    2010-01-01

    Relying on heat generated by plasma arc heating liquid water into steam as a swirl gas, a water plasma torch has the distinctive steam generation structure, which has various applications such as in the treatment of organic waste and hydrogen production for fuel cells in future vehicles. The operational features of the water plasma torch and water phase change process in the discharge chamber are investigated based on the temporal evolution of the voltage and current. The optical emission spectrum measurement shows that the water molecule in the plasma is decomposed into H, OH and O radicals. As the electrodes do not require water-cooling, the thermal efficiency of the torch is very high, which is confirmed by analytical calculation and experimental measurement

  11. Stress hysteresis during thermal cycling of plasma-enhanced chemical vapor deposited silicon oxide films

    Science.gov (United States)

    Thurn, Jeremy; Cook, Robert F.

    2002-02-01

    The mechanical response of plasma-enhanced chemical vapor deposited SiO2 to thermal cycling is examined by substrate curvature measurement and depth-sensing indentation. Film properties of deposition stress and stress hysteresis that accompanied thermal cycling are elucidated, as well as modulus, hardness, and coefficient of thermal expansion. Thermal cycling is shown to result in major plastic deformation of the film and a switch from a compressive to a tensile state of stress; both athermal and thermal components of the net stress alter in different ways during cycling. A mechanism of hydrogen incorporation and release from as-deposited silanol groups is proposed that accounts for the change in film properties and state of stress.

  12. Calcium titanate (CaTiO{sub 3}) dielectrics prepared by plasma spray and post-deposition thermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Ctibor, Pavel [Materials Engineering Department, Institute of Plasma Physics ASCR, v.v.i., Za Slovankou 3, Prague 8 (Czech Republic); Kotlan, Jiri, E-mail: kotlan@ipp.cas.cz [Materials Engineering Department, Institute of Plasma Physics ASCR, v.v.i., Za Slovankou 3, Prague 8 (Czech Republic); Department of Electrotechnology, Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, Prague 6 (Czech Republic); Pala, Zdenek [Materials Engineering Department, Institute of Plasma Physics ASCR, v.v.i., Za Slovankou 3, Prague 8 (Czech Republic); Sedlacek, Josef [Department of Electrotechnology, Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, Prague 6 (Czech Republic); Hajkova, Zuzana; Grygar, Tomas Matys [Institute of Inorganic Chemistry ASCR, v.v.i., Husinec-Rez 1001, Rez (Czech Republic)

    2015-12-15

    Highlights: • Calcium titanate was sprayed by two different plasma spray systems. • Significant improvement of dielectric properties after annealing was observed. • Calcium titanate self-supporting parts can be fabricated by plasma spraying. - Abstract: This paper studies calcium titanate (CaTiO{sub 3}) dielectrics prepared by plasma spray technology. A water stabilized plasma gun (WSP) as well as a widely used gas stabilized plasma gun (GSP) were employed in this study to deposit three sample sets at different spray conditions. Prepared specimens were annealed in air at atmospheric pressure for 2 h at various temperatures from 530 to 1170 °C. X-ray diffraction (XRD), Raman spectroscopy and porosity measurements were used for sample characterization. Dielectric spectroscopy was applied to obtain relative permittivity, conductivity and loss factor frequency dependence. Band gap energy was estimated from reflectance measurements. The work is focused on the explanation of changes in microstructure and properties of a plasma sprayed deposit after thermal annealing. Obtained results show significant improvement of dielectric properties after thermal annealing.

  13. Failure Analysis of Multilayered Suspension Plasma-Sprayed Thermal Barrier Coatings for Gas Turbine Applications

    Science.gov (United States)

    Gupta, M.; Markocsan, N.; Rocchio-Heller, R.; Liu, J.; Li, X.-H.; Östergren, L.

    2018-02-01

    Improvement in the performance of thermal barrier coatings (TBCs) is one of the key objectives for further development of gas turbine applications. The material most commonly used as TBC topcoat is yttria-stabilized zirconia (YSZ). However, the usage of YSZ is limited by the operating temperature range which in turn restricts the engine efficiency. Materials such as pyrochlores, perovskites, rare earth garnets are suitable candidates which could replace YSZ as they exhibit lower thermal conductivity and higher phase stability at elevated temperatures. The objective of this work was to investigate different multilayered TBCs consisting of advanced topcoat materials fabricated by suspension plasma spraying (SPS). The investigated topcoat materials were YSZ, dysprosia-stabilized zirconia, gadolinium zirconate, and ceria-yttria-stabilized zirconia. All topcoats were deposited by TriplexPro-210TM plasma spray gun and radial injection of suspension. Lifetime of these samples was examined by thermal cyclic fatigue and thermal shock testing. Microstructure analysis of as-sprayed and failed specimens was performed with scanning electron microscope. The failure mechanisms in each case have been discussed in this article. The results show that SPS could be a promising route to produce multilayered TBCs for high-temperature applications.

  14. Characteristics of the Plasma Source for Ground Ionosphere Simulation Surveyed by Disk-Type Langmuir Probe

    Science.gov (United States)

    Ryu, Kwangsun; Lee, Junchan; Kim, Songoo; Chung, Taejin; Shin, Goo-Hwan; Cha, Wonho; Min, Kyoungwook; Kim, Vitaly P.

    2017-12-01

    A space plasma facility has been operated with a back-diffusion-type plasma source installed in a mid-sized vacuum chamber with a diameter of 1.5 m located in Satellite Technology Research Center (SaTReC), Korea Advanced Institute of Science and Technology (KAIST). To generate plasma with a temperature and density similar to the ionospheric plasma, nickel wires coated with carbonate solution were used as filaments that emit thermal electrons, and the accelerated thermal electrons emitted from the heated wires collide with the neutral gas to form plasma inside the chamber. By using a disk-type Langmuir probe installed inside the vacuum chamber, the generation of plasma similar to the space environment was validated. The characteristics of the plasma according to the grid and plate anode voltages were investigated. The grid voltage of the plasma source is realized as a suitable parameter for manipulating the electron density, while the plate voltage is suitable for adjusting the electron temperature. A simple physical model based on the collision cross-section of electron impact on nitrogen molecule was established to explain the plasma generation mechanism.

  15. Effects of external magnetic field on harmonics generated in laser interaction with underdense plasma

    International Nuclear Information System (INIS)

    Faghihi-Nik, M.; Ghorbanalilu, M.; Shokri, B.

    2010-01-01

    Complete text of publication follows. Generation of harmonic radiation is an important subject of laser plasma interaction and attracts great attention due to a wide range of applications. It has been seen that intense electromagnetic and quasi-static transverse magnetic fields are generated in laser plasma interaction. An extremely intense magnetic field (up to hundreds of MG) has been observed by experimental measurements in interaction of short laser pulses with plasma. These self-generated or applied magnetic fields affect the propagation of the laser pulses. In most laser interactions with homogeneous plasma, odd harmonics of laser frequency are generated. In this paper, we point out the possibility of even harmonics generation when a linearly polarized laser beam propagates in homogeneous plasma in the presence of a transverse magnetic field. It is shown that applying external field induces a transverse current density oscillating twice of the laser field which leds to generation of second harmonic radiation. This current density is derived using the perturbation method, and the steady state amplitude of the second harmonic obtained by solution of the wave equation. By the same procedure the current density and then the steady state amplitude of higher order harmonics are calculated. The efficiency of harmonic generation (the ratio of harmonic power to incident power) is a drastically function of the strength of external magnetic field. It is found that the efficiency of even harmonics is zero in the absence of magnetic field and increases as the magnetic field is increased. For odd harmonics, applying the external magnetic field enhances the generated harmonics as well. The conversion efficiency also increases with increase in plasma density and intensity of the laser beam.

  16. Mapping return currents in laser-generated Z-pinch plasmas using proton deflectometry

    International Nuclear Information System (INIS)

    Manuel, M. J.-E.; Sinenian, N.; Seguin, F. H.; Li, C. K.; Frenje, J. A.; Rinderknecht, H. G.; Casey, D. T.; Zylstra, A. B.; Petrasso, R. D.; Beg, F. N.

    2012-01-01

    Dynamic return currents and electromagnetic field structure in laser-generated Z-pinch plasmas have been measured using proton deflectometry. Experiments were modeled to accurately interpret deflections observed in proton radiographs. Current flow is shown to begin on axis and migrate outwards with the expanding coronal plasma. Magnetic field strengths of ∼1 T are generated by currents that increase from ∼2 kA to ∼7 kA over the course of the laser pulse. Proton deflectometry has been demonstrated to be a practical alternative to other magnetic field diagnostics for these types of plasmas.

  17. Transport and deposition of injected hydrocarbons in plasma generator PSI-2

    International Nuclear Information System (INIS)

    Bohmeyer, W.; Naujoks, D.; Markin, A.; Arkhipov, I.; Koch, B.; Schroeder, D.; Fussmann, G.

    2005-01-01

    The transport and deposition of hydrocarbons were studied in the stationary plasma of plasma generator PSI-2. CH 4 or C 2 H 4 were injected into the plasma at different positions in the target chamber. After an interaction between the plasma and the hydrocarbons, different species are produced, some of them having high sticking probabilities and forming a:CH films on a temperature controlled collector. The film growth is studied in situ for different plasma parameters. The 3D Monte Carlo code ERO including three different sets of atomic data is used to describe the formation of hydrocarbon films

  18. Full-wave Simulations of LH Wave Propagation in Toroidal Plasma with non-Maxwellian Electron Distributions

    International Nuclear Information System (INIS)

    Valeo, E.J.; Phillips, C.K.; Bonoli, P.T.; Wright, J.C.; Brambilla, M.

    2007-01-01

    The generation of energetic tails in the electron distribution function is intrinsic to lower-hybrid (LH) heating and current drive in weakly collisional magnetically confined plasma. The effects of these deformations on the RF deposition profile have previously been examined within the ray approximation. Recently, the calculation of full-wave propagation of LH waves in a thermal plasma has been accomplished using an adaptation of the TORIC code. Here, initial results are presented from TORIC simulations of LH propagation in a toroidal plasma with non-thermal electrons. The required efficient computation of the hot plasma dielectric tensor is accomplished using a technique previously demonstrated in full-wave simulations of ICRF propagation in plasma with non-thermal ions

  19. HNS steelmaking process using thermal plasma in a ceramic crucible

    International Nuclear Information System (INIS)

    Siwka, J.; Svyazhin, A.G.; Jowsa, J.; Derda, W.

    1999-01-01

    The problems related to HNS (high nitrogen steels) steelmaking technology in a laboratory plasma furnace (100 kW DC, 25 kg liquid metal) are discussed in the paper. Results of investigations on mass transfer in the bath, modelling of the temperature fields by the FEM method, the dynamics of nitriding and refining of the liquid metal are presented. The results show many advantageous features of this technology and identify the necessary modifications. Realization of the one-stage production process of HNS is possible using thermal plasma. This means that any kind of metallic scrap can be used with simultaneous nitriding of liquid metal by nitrogen gas phase and its refining. A technological scheme of the discussed process is presented. (orig.)

  20. Interaction of EM Waves with Atmospheric Pressure Plasmas

    National Research Council Canada - National Science Library

    Laroussi, Mounir

    2000-01-01

    .... The focus of the main activities is the generation of large volume, non-thermal, atmospheric pressure plasmas, their diagnostics, and their interactions with EM waves and with the cells of microorganism...