Experimental study of membrane pump for plasma devices

International Nuclear Information System (INIS)

Suzuki, Hajime; Ohyabu, Nobuyoshi; Nakamura, Yukio; Sagara, Akio; Motojima, Osamu; Livshits, A.; Notkin, M.; Busnyuk, A.; Komatsu, Kazuyuki

1998-01-01

Recycling control is a key to improve fusion plasma performance. The membrane pump has potential advantages for hydrogen pumping in fusion devices. However, there are unsolved issues for using membrane pump in LHD (Large Helical Device). The first issue is characteristics of the membrane pump under high incident hydrogen atom flux. The second issue is relationship between the surface condition and the pumping efficiency. Impurities from plasma may change the surface condition of the membrane. In order to solve these issues, a membrane pump system was fabricated and installed in a linear plasma device at NIFS (National Institute for Fusion Science). The membrane pump was successfully operated. (author)

Matching of dense plasma focus devices with fission reactors

International Nuclear Information System (INIS)

Harms, A.A.; Heindler, M.

1978-01-01

The potential role of dense plasma focus devices as compact neutron sources for fissile fuel breeding in conjunction with existing fission reactors is considered. It is found that advanced plasma focus devices can be used effectively in conjunction with neutronically efficient fission reactors to constitute ''self-sufficient'' breeders. Correlations among the various parameters such as the power output and conversion ratio of the fission reactor with the neutron yield and capacitor bank energy of the dense plasma focus device are presented and discussed

Parametric studies in a small plasma focus device

International Nuclear Information System (INIS)

Chuaqui, H.; Favre, M.; Silva, P.; Wyndham, E.

1996-01-01

Very high temperature and density plasmas can be produced in modest size plasma focus devices at the kJ level. Much of the scaling parameters on the plasma focus have been evaluated, though many questions still remain. The modest cost and simple construction allows easy modification to the device and the discharge parameters. In this paper the authors report on a small plasma focus device, which is set-up to investigate the effect of some of those modifications on the plasma, with detailed experimental diagnostics. Experiments have been carried out in various gases and with mixtures of different ratios. Extended operating range from below 0.5 torr upwards has been achieved with the implementation of the auxiliary discharge circuit. Despite the low voltage and low energy operation, energetic beam formation has been observed at the time of the final compression, prior to disruption. Current sheath formation and evolution has been characterized using the magnetic probes array, in correlation with beam formation and plasma emission. The relationship of the current sheath structure and that of the pinched plasma, as shown by the filtered X-ray pinhole camera, has been investigated

High beta plasma operation in a toroidal plasma producing device

International Nuclear Information System (INIS)

Clarke, J.F.

1978-01-01

A high beta plasma is produced in a plasma producing device of toroidal configuration by ohmic heating and auxiliary heating. The plasma pressure is continuously monitored and used in a control system to program the current in the poloidal field windings. Throughout the heating process, magnetic flux is conserved inside the plasma and the distortion of the flux surfaces drives a current in the plasma. As a consequence, the total current increases and the poloidal field windings are driven with an equal and opposing increasing current. The spatial distribution of the current in the poloidal field windings is determined by the plasma pressure. Plasma equilibrium is maintained thereby, and high temperature, high beta operation results

Origin of fluctuations in atmospheric pressure arc plasma devices

International Nuclear Information System (INIS)

Ghorui, S.; Das, A.K.

2004-01-01

Fluctuations in arc plasma devices are extremely important for any technological application in thermal plasma. The origin of such fluctuations remains unexplained. This paper presents a theory for observed fluctuations in atmospheric pressure arc plasma devices. A qualitative explanation for observed behavior on atmospheric pressure arc plasma fluctuations, reported in the literature, can be obtained from the theory. The potential of the theory is demonstrated through comparison of theoretical predictions with reported experimental observations

In-liquid plasma devices and methods of use thereof

KAUST Repository

Cha, Min Suk

2017-08-10

Devices and methods for generating a plasma in a liquid are provided. A low- dielectric material can be placed in contact with the liquid to form an interface a distance from an anode. A voltage can be applied across the anode and a cathode submerged in the liquid to produce the plasma. A variety of devices are provided, including for continuous operation. The devices and methods can be used to generate a plasma in a variety of liquids, for example for water treatment, hydrocarbon reformation, or synthesis of nanomaterial.

Compression Models for Plasma Focus Devices

International Nuclear Information System (INIS)

Gonzalez, Jose; Calusse, Alejandro; Ramos, Ruben; Rodriguez Palomino, Luis

2003-01-01

Using a numerical model that calculates the dynamics of Plasma Focus devices, we compared the results of three different compression models of the plasma pinch.One of the main objectives in this area is to develop a simplified model to calculate the neutron production of Plasma Focus devices, to study the influence of the main parameters in this neutron yield.The dynamics is thoroughly studied, and the model predicts fairly well values such as maximum currents and times for pinch collapse.Therefore, we evaluate here different models of pinch compression, to try to predict the neutron production with good agreement with the rest of the variables involved.To fulfill this requirement, we have experimental results of neutron production as a function of deuterium filling pressure in the chamber, and typical values of other main variables in the dynamics of the current sheet

Analysis of plasma behavior and electro-magnetic interaction between plasma and device

International Nuclear Information System (INIS)

Kobayashi, Tomofumi

1980-01-01

A simulation program for the analysis of plasma behavior and the electromagnetic interaction between plasma and device has been developed. The program consists of a part for the analysis of plasma behavior (plasma system) and a part for the analysis of the electro-magnetic interaction between plasma and devices (circuit system). The parameters which connect the plasma system and the circuit system are the electric resistance of plasma, the internal inductance, and the plasma current. For the plasma system, the simultaneous equations which describe the density distribution of plasma particles, the temperature distribution of electrons and ions, and the space-time variation of current density distribution were derived. The one-dimensional plasma column in γ-direction was considered. The electric resistance and the internal inductance can be deduced. The circuit components are a current transformer, a vertical field coil, a quadrupole field coil, a vacuum chamber and others. An equation which describes plasma position and the shape of cross section is introduced. The plasma position can be known by solving the Mukhavatov's formula of equilibrium. By using this program, the build-up process of plasma current in JT-60 was analysed. It was found that the expansion of plasma sub radius and the control of current distribution by gas injection are the effective methods to obtain high temperature and high density plasma. The eddy current induced in a vacuum vessel shields 40 percent of magnetic field made in the plasma region by a vertical field coil. (Kato, T.)

Plasma devices for focusing extreme light pulses

International Nuclear Information System (INIS)

Fuchs, J.; Gonoskov, A.A.; Nakatsutsumi, M.; Nazarov, W.; Quere, F.; Sergeev, A.M.; Yan, X.Q.

2014-01-01

Since the inception of the laser, there has been a constant push toward increasing the laser peak intensity, as this has lead to opening the exploration of new territories, and the production of compact sources of particles and radiation with unprecedented characteristics. However, increasing the peak laser intensity is usually performed by enhancing the produced laser properties, either by lowering its duration or increasing its energy, which involves a great level of complexity for the laser chain, or comes at great cost. Focusing tightly is another possibility to increase the laser intensity, but this comes at the risk of damaging the optics with target debris, as it requires their placement in close proximity to the interaction region. Plasma devices are an attractive, compact alternative to tightly focus extreme light pulses and further increase the final laser intensity. (authors)

Experimental validation of models for Plasma Focus devices

International Nuclear Information System (INIS)

Rodriguez Palomino, Luis; Gonzalez, Jose; Clausse, Alejandro

2003-01-01

Plasma Focus(PF) Devices are thermonuclear pulsators that produce short pulsed radiation (X-ray, charged particles and neutrons). Since Filippov and Mather, investigations have been used to study plasma properties. Nowadays the interest about PF is focused in technology applications, related to the use of these devices as pulsed neutron sources. In the numerical calculus the Inter institutional PLADEMA (PLAsmas DEnsos MAgnetizados) network is developing three models. Each one is useful in different engineering stages of the Plasma Focus design. One of the main objectives in this work is a comparative study on the influence of the different parameters involved in each models. To validate these results, several experimental measurements under different geometry and initial conditions were performed. (author)

Review and perspectives of electrostatic turbulence and transport studies in the basic plasma physics device TORPEX

Science.gov (United States)

Avino, Fabio; Bovet, Alexandre; Fasoli, Ambrogio; Furno, Ivo; Gustafson, Kyle; Loizu, Joaquim; Ricci, Paolo; Theiler, Christian

2012-10-01

TORPEX is a basic plasma physics toroidal device located at the CRPP-EPFL in Lausanne. In TORPEX, a vertical magnetic field superposed on a toroidal field creates helicoidal field lines with both ends terminating on the torus vessel. We review recent advances in the understanding and control of electrostatic interchange turbulence, associated structures and their effect on suprathermal ions. These advances are obtained using high-resolution diagnostics of plasma parameters and wave fields throughout the whole device cross-section, fluid models and numerical simulations. Furthermore, we discuss future developments including the possibility of generating closed field line configurations with rotational transform using an internal toroidal wire carrying a current. This system will also allow the study of innovative fusion-relevant configurations, such as the snowflake divertor.

A new linear plasma device for the study of plasma waves in the electron magnetohydrodynamics regime

Science.gov (United States)

Joshi, Garima; Ravi, G.; Mukherjee, S.

2018-06-01

A new, user-friendly, linear plasma device has been developed in our laboratory where a quiescent (Δ n/n ≈ 1%), low temperature (1-10 eV), pulsed (3-10 ms) plasma can be produced over a large uniform region of 30-40 cm diameter and 40 cm length. Salient features of the device include the flexibility of tuning the plasma density in the range of 10^{10} to 10^{12} cm^{-3} and capability of scanning the plasma and field parameters in two dimensions with a precision of electromagnetic field parameters by miniature magnetic probes and Rogowski coils. The plasma produced is uniform and essentially unbounded for performing experiments on waves and turbulence. The whole device can be operated single-handedly by undergraduate or graduate students. The device can be opened, serviced, new antennas/probes installed and ready for operation in a matter of hours. Some results on the excitation of electromagnetic structures in the context of electron magnetohydrodynamics (EMHD) are also presented to demonstrate the suitability of the device for carrying out such experiments.

Plasma control device

International Nuclear Information System (INIS)

Takase, Haruhiko.

1987-01-01

Purpose: To obtain the optimum controllability for the plasmas and the thermonuclear device by selectively executing control operation for proportion, integration and differentiation (PID) by first and second controllers respectively based on selection instruction signals. Constitution: Deviation between a vertical direction equilibrium position: Zp as the plasma status amount measured in a measuring section and an aimed value Zref thereof is inputted to a first PID selection controller. The first controller selectively executes one of the PID control operations in accordance with the first selection signal instruction instructed by a PID control operation instruction circuit. Further, Zp is also inputted to a second PID selection controller, which selectively executes one of the PID control operations in accordance with the second selection instruction signal in the same manner as in the first controller. The deviation amount u between operations signals u1 and u2 from the first and second PID selection controllers is inputted to a power source to thereby supply a predetermined current value to control coils that generate equilibrium magnetic fields for making the vertical direction equilibrium position of plasmas constant. (Kamimura, M.)

Challenges for Plasma Diagnostic in a Next Step Device (FIRE)

International Nuclear Information System (INIS)

Young, Kenneth M.

2002-01-01

The physics program of any next-step tokamak such as FIRE [Fusion Ignition Research Experiment] sets demands for plasma measurement which are at least as comprehensive as on present tokamaks, with the additional capabilities needed for control of the plasma and for understanding the effects of the alpha-particles. The diagnostic instrumentation must be able to provide the fine spatial and temporal resolution required for the advanced tokamak plasma scenarios. It must also be able to overcome the effects of neutron- and gamma-induced electrical noise in ceramic components or detectors, and fluorescence and absorption in optical components. There are practical engineering issues of minimizing radiation streaming while providing essential diagnostic access to the plasma. Many diagnostics will require components at or close to the first wall, e.g., ceramics and MI cable for magnetic diagnostics and mirrors for optical diagnostics; these components must be mounted to operate, and survive, i n fluxes which require special material selection. A better set of diagnostics of alpha-particles than that available for the TFTR [Tokamak Fusion Test Reactor] is essential; it must be qualified well before moving into D-T [deuterim-tritium] experiments. A start has been made to assessing the potential implementation of key diagnostics for the FIRE device. The present status is described

Plasma Surface interaction in Controlled fusion devices

International Nuclear Information System (INIS)

1990-05-01

The subjects presented in the 9th conference on plasma surface interaction in controlled fusion devices were: the modifications of power scrape-off-length and power deposition during various configurations in Tore Supra plasmas; the effects observed in ergodic divertor experiments in Tore-Supra; the diffuse connexion induced by the ergodic divertor and the topology of the heat load patterns on the plasma facing components in Tore-Supra; the study of the influence of air exposure on graphite implanted by low energy high density deuterium plasma

Experimental investigation of vapor shielding effects induced by ELM-like pulsed plasma loads using the double plasma gun device

Science.gov (United States)

Sakuma, I.; Kikuchi, Y.; Kitagawa, Y.; Asai, Y.; Onishi, K.; Fukumoto, N.; Nagata, M.

2015-08-01

We have developed a unique experimental device of so-called double plasma gun, which consists of two magnetized coaxial plasma gun (MCPG) devices, in order to clarify effects of vapor shielding on material erosion due to transient events in magnetically confined fusion devices. Two ELM-like pulsed plasmas produced by the two MCPG devices were injected into a target chamber with a variable time difference. For generating ablated plasmas in front of a target material, an aluminum foil sample in the target chamber was exposed to a pulsed plasma produced by the 1st MCPG device. The 2nd pulsed plasma was produced with a time delay of 70 μs. It was found that a surface absorbed energy measured by a calorimeter was reduced to ∼66% of that without the Al foil sample. Thus, the reduction of the incoming plasma energy by the vapor shielding effect was successfully demonstrated in the present experiment.

Experimental investigation of vapor shielding effects induced by ELM-like pulsed plasma loads using the double plasma gun device

Energy Technology Data Exchange (ETDEWEB)

Sakuma, I., E-mail: eu13z002@steng.u-hyogo.ac.jp; Kikuchi, Y.; Kitagawa, Y.; Asai, Y.; Onishi, K.; Fukumoto, N.; Nagata, M.

2015-08-15

We have developed a unique experimental device of so-called double plasma gun, which consists of two magnetized coaxial plasma gun (MCPG) devices, in order to clarify effects of vapor shielding on material erosion due to transient events in magnetically confined fusion devices. Two ELM-like pulsed plasmas produced by the two MCPG devices were injected into a target chamber with a variable time difference. For generating ablated plasmas in front of a target material, an aluminum foil sample in the target chamber was exposed to a pulsed plasma produced by the 1st MCPG device. The 2nd pulsed plasma was produced with a time delay of 70 μs. It was found that a surface absorbed energy measured by a calorimeter was reduced to ∼66% of that without the Al foil sample. Thus, the reduction of the incoming plasma energy by the vapor shielding effect was successfully demonstrated in the present experiment.

Device for closing the radioactive sources shutters

International Nuclear Information System (INIS)

Teixeira, Everaldo; Santos, Enderson Silvino; Vieira, Carlaine M.; Torquato, Nivaldo Reis; Santos, Evando Ramalho; Castro, Luciano Sampaio

2002-01-01

A device for nuclear measurement used at the industrial installation is composed of a radioactive source (Cs 137), the ionization or scintillation chamber and the circuitry parts. The ionization and scintillation chambers are mounted at the industrial piping and monitoring the density of the material inside the piping, based on radiation quantity which comes to receiving chamber. This information is sending to the electronic unity which is responsible for the calculations and remote and local indications of the measured density. Based on the recommendation of the radioactive sources must have the shutters closed when they are inactive, an automatic device composed by solenoid valve, a support and a mechanical shaft which when connected to the supervisory system (CLP's) cause the automatic closing of the shutter of the radioactive sources during the shutting down of the process

Air core poloidal magnetic field system for a toroidal plasma producing device

International Nuclear Information System (INIS)

Marcus, F.B.

1978-01-01

A poloidal magnetics system for a plasma producing device of toroidal configuration is provided that reduces both the total volt-seconds requirement and the magnitude of the field change at the toroidal field coils. The system utilizes an air core transformer wound between the toroidal field (TF) coils and the major axis outside the TF coils. Electric current in the primary windings of this transformer is distributed and the magnetic flux returned by air core windings wrapped outside the toroidal field coils. A shield winding that is closely coupled to the plasma carries a current equal and opposite to the plasma current. This winding provides the shielding function and in addition serves in a fashion similar to a driven conducting shell to provide the equilibrium vertical field for the plasma. The shield winding is in series with a power supply and a decoupling coil located outside the TF coil at the primary winding locations. The present invention requires much less energy than the usual air core transformer and is capable of substantially shielding the toroidal field coils from poloidal field flux

Arc plasma devices: Evolving mechanical design from numerical

Indian Academy of Sciences (India)

A recipe for obtaining mechanical design of arc plasma devices from numerical ... to the plasma of the mixture of molecular gases like nitrogen and oxygen. ... Temperature field, associated fluid dynamics and electrical characteristics of a ...

Device for plasma confinement and heating by high currents and nonclassical plasma transport properties

Science.gov (United States)

Coppi, B.; Montgomery, D.B.

1973-12-11

A toroidal plasma containment device having means for inducing high total plasma currents and current densities and at the same time emhanced plasma heating, strong magnetic confinement, high energy density containment, magnetic modulation, microwaveinduced heating, and diagnostic accessibility is described. (Official Gazette)

Detection of x-rays emitted from a plasma focus device with energy of 2.8 KJ, and its applications in plasma diagnostic and radiography

International Nuclear Information System (INIS)

AL-Hawat, Sh.; Akel, M.

2011-06-01

The local plasma focus device was modified by replacing the old capacitors (25μF,20 kV ,1.43μH ) and the open spark gap by new capacitors with (25μF,20 kV ,200 nH ) and a new closed spark gap, so instead of a current of 50 kA as a maximum value we obtained a maximum current about 120 kA. The modified device is capable now to generate x-rays, which was confirmed by taking some radiographies for metallic pieces, electronic elements and others . In addition to that some diagnostics were carried out on the device using Ohm voltage divider to record voltage curves, Rogovskii coil for measuring the current, and five channel diodes to evaluate the temporal evolution of x-rays generated in the device working on argon vs. pressure and voltage. The generation of the soft x-ray emission in a low energy 2.8 kJ plasma focus device operated with argon using a detector of five PIN-Si BPX-65 diodes filtered with different foils of Mylar, Al and Cu. Spectral analysis using the recorded x-ray signals ratio method shows that there are two components in the x-ray emissions: one arising from the focused argon plasma with temperature of 2.5 keV and the other arising from the electron beam activity on copper anode, where the second component is predominant in most of investigated experiments due to the used of solid anode. Numerical experiments were carried out using five phases radiative Lee model RADPF5.15d-dd with N 2 , O 2 , Ar, Ne gases on plasma focus device AECS PF1-2 (or PF SY1-2) for its characterization and soft x-ray optimization. (author)

Physics and technology of large plasma focus devices

International Nuclear Information System (INIS)

Herold, H.

1990-01-01

This paper reports on the plasma focus (PF) which produces a high temperature (0,5 to 1 keV), high density (5 · 10 18 cm -3 ), short living (up to 500 ns) fusion plasma in a very simple and cheap device. In the focus plasma, fusion processes take place with an energy efficiency which is not surpassed even by large Tokamak or Inertial Confinement Fusion devices. But this fusion efficiency and the high fusion neutron yield are not the only impetus to PF research. Due to the high energy density in the focus plasma (j ≥ 10 6 A/cm 2 exclamation point), many very interesting, mostly nonlinear phenomena take place which led to high intensity electron, ion and radiation emission. Micro- and macro instabilities, turbulence and selforganization processes develop. Most of these phenomena are not or only poorly understood

Recent results on medium-size plasma-focus device

International Nuclear Information System (INIS)

Miklaszewski, R.; Kasperczuk, A.; Paduch, M.; Tomaszewaski, K.; Wereszczynski, Z.

1992-01-01

A brief history of investigation carried out on the PF-150 plasma-focus device is presented. Essential results concerning the dynamics of plasma sheath are summarized. The present state of investigation and main areas of interest are shown. (author)

Plasma Equilibrium Control in Nuclear Fusion Devices 2. Plasma Control in Magnetic Confinement Devices 2.1 Plasma Control in Tokamaks

Science.gov (United States)

Fukuda, Takeshi

The plasma control technique for use in large tokamak devices has made great developmental strides in the last decade, concomitantly with progress in the understanding of tokamak physics and in part facilitated by the substantial advancement in the computing environment. Equilibrium control procedures have thereby been established, and it has been pervasively recognized in recent years that the real-time feedback control of physical quantities is indispensable for the improvement and sustainment of plasma performance in a quasi-steady-state. Further development is presently undertaken to realize the “advanced plasma control” concept, where integrated fusion performance is achieved by the simultaneous feedback control of multiple physical quantities, combined with equilibrium control.

Plasma edge and plasma-wall interaction modelling: Lessons learned from metallic devices

Directory of Open Access Journals (Sweden)

S. Wiesen

2017-08-01

Full Text Available Robust power exhaust schemes employing impurity seeding are needed for target operational scenarios in present day tokamak devices with metallic plasma-facing components (PFCs. For an electricity-producing fusion power plant at power density Psep/R>15MW/m divertor detachment is a requirement for heat load mitigation. 2D plasma edge transport codes like the SOLPS code as well as plasma-wall interaction (PWI codes are key to disentangle relevant physical processes in power and particle exhaust. With increased quantitative credibility in such codes more realistic and physically sound estimates of the life-time expectations and performance of metallic PFCs can be accomplished for divertor conditions relevant for ITER and DEMO. An overview is given on the recent progress of plasma edge and PWI modelling activities for (carbon-free metallic devices, that include results from JET with the ITER-like wall, ASDEX Upgrade and Alcator C-mod. It is observed that metallic devices offer an opportunity to progress the understanding of underlying plasma physics processes in the edge. The validation of models can be substantially improved by eliminating carbon from the experiment as well as from the numerical system with reduced degrees of freedom as no chemical sputtering from amorphous carbon layers and no carbon or hydro-carbon transport are present. With the absence of carbon as the primary plasma impurity and given the fact that the physics of the PWI at metallic walls is less complex it is possible to isolate the crucial plasma physics processes relevant for particle and power exhaust. For a reliable 2D dissipative plasma exhaust model these are: cross-field drifts, complete kinetic neutral physics, geometry effects (including main-chamber, divertor and sub-divertor structures, SOL transport reflecting also the non-diffusive nature of anomalous transport, as well as transport within the pedestal region in case of significant edge impurity radiation

Intermittent transport in edge plasma with a 3-D magnetic geometry in the Large Helical Device

International Nuclear Information System (INIS)

Tanaka, H.; Masuzaki, S.; Ohno, N.; Morisaki, T.; Tsuji, Y.

2013-01-01

Blobby plasma transport is a universally observed phenomenon in magnetic confinement devices, and it is considered to be closely related to edge plasma physics. We have investigated such an intermittent event observed inside the divertor region of the Large Helical Device by using a fast-scanning Langmuir probe with two electrodes. Ion saturation current fluctuations showed negative spikes in the divertor leg and positive spikes in the private region. Further, the time delay between the two fluctuations followed a unique trajectory in the positive-skewness region. We found common as well as different fluctuation characteristics between the LHD and tokamaks. We discuss the analysis results in relation to the blob-generation and propagation behaviors in the three-dimensional magnetic geometry around the divertor leg. In addition, we quantitatively estimated the blob propagation velocity and size based on a theoretical assumption

Analysis of plasma instabilities and verification of the BOUT code for the Large Plasma Device

International Nuclear Information System (INIS)

Popovich, P.; Carter, T. A.; Friedman, B.; Umansky, M. V.

2010-01-01

The properties of linear instabilities in the Large Plasma Device [W. Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)] are studied both through analytic calculations and solving numerically a system of linearized collisional plasma fluid equations using the three-dimensional fluid code BOUT[M. Umansky et al., Contrib. Plasma Phys. 180, 887 (2009)], which has been successfully modified to treat cylindrical geometry. Instability drive from plasma pressure gradients and flows is considered, focusing on resistive drift waves and the Kelvin-Helmholtz and rotational interchange instabilities. A general linear dispersion relation for partially ionized collisional plasmas including these modes is derived and analyzed. For Large Plasma Device relevant profiles including strongly driven flows, it is found that all three modes can have comparable growth rates and frequencies. Detailed comparison with solutions of the analytic dispersion relation demonstrates that BOUT accurately reproduces all characteristics of linear modes in this system.

A new linear plasma device for various edge plasma studies at SWIP

Science.gov (United States)

Xu, Min; Zheng, Pengfei; Tynan, George; Che, Tong; Wang, Zhanhui; Guo, Dong; Wei, Ran

2017-10-01

To facilitate the plasma-material interactions (PMI) studies, Southwestern Institute of Physics (SWIP) has constructed a linear plasma device. It is comprised of a source chamber (Φ 0.4 m), a target chamber (Φ 0.9 m), 15 magnets with different sizes, and power supplies with the total power of a few hundred kilowatts, etc. A maximum magnetic field of 0.3 Tesla along the axial direction can be produced. The current of each of the 15 magnets can be independently controlled. More than 60 ports are available for diagnostics, with the sizes vary from Φ 50 mm to Φ 150 mm. Rectangular ports of 190 mm × 270 mm are also available. 12 ports looking at the sample holder are specially designed for ion beam injection, of which the axes are 25 to the chamber axis. The device is equipped with a LaB6 hot cathode plasma source, which is able to generate steady-state H/D/He plasmas with a diameter of Φ 100 mm, density of 1x1019 /m3 , and a particle flux of 1022 1023 n/m2 .s. The electron temperature is usually a few eV. Further, a Helicon RF plasma source is also planned for plasma transport studies. Int'l Sci & Tech Cooperation Program of China (No. 2015DFA61760).

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.

21 CFR 864.9205 - Blood and plasma warming device.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Blood and plasma warming device. 864.9205 Section 864.9205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Products Used In Establishments That Manufacture...

RF-heating and plasma confinement studies in HANBIT mirror device

International Nuclear Information System (INIS)

Kwon, M.; Bak, J.G.; Choh, K.K.

2003-01-01

HANBIT is a magnetic mirror confinement device. Recently, with almost finishing the first campaign for the basic system development, it started the second campaign for the high-temperature plasma confinement physics study in mirror configuration. Here, we introduce briefly the HANBIT device and report initial physics experiments results on RF-plasma heating and confinement in the simple mirror configuration. It appears that the discharge characteristics of HANBIT are quite different from those in other mirror devices, and an explanation is presented to clarify the difference. (author)

Metastable states of plasma particles close to a charged surface

Energy Technology Data Exchange (ETDEWEB)

Shavlov, A. V., E-mail: shavlov@ikz.ru [The Institute of the Earth Cryosphere, RAS Siberian branch, 625000, P.O. 1230, Tyumen (Russian Federation); Tyumen State Oil and Gas University, 38, Volodarskogo St., 625000, Tyumen (Russian Federation); Dzhumandzhi, V. A. [The Institute of the Earth Cryosphere, RAS Siberian branch, 625000, P.O. 1230, Tyumen (Russian Federation)

2015-09-15

The free energy of the plasma particles and the charged surface that form an electroneutral system is calculated on the basis of the Poisson-Boltzmann equation. It is shown that, owing to correlation of light plasma particles near the charged surface and close to heavy particles of high charge, there can be metastable states in plasma. The corresponding phase charts of metastable states of the separate components of plasma, and plasma as a whole, are constructed. These charts depend on temperature, the charge magnitude, the size of the particles, and the share of the charge of the light carriers out of the total charge of the plasma particles.

Platelet-rich plasma: updating of extraction devices

Directory of Open Access Journals (Sweden)

Raquel Moreno

2016-12-01

Full Text Available Propose: To describe PRP extraction devices, through a review of kits available in Spain, taking into account AEMPS and SEFH working groups (GPS, Farmacotecnia, Hemoderivados groups contributions. Methods: Three independent searches about PRP extraction devices were carried out. Device suppliers were contacted and an individually meeting was called with each one. Characteristics of each device was reviewed by virtual demonstration. A kits comparison chart was made with all the information acquired. Kits were classified as Closed-Technique and Opened- Technique in accordance with the AEMPS technical committee report. Results: Ten devices were found: ACP®; Angel®, Cascade®, Endoret ®, GPS®, Magellan®, Minos®, Ortho-pras®, Smart-prepr® and Tricell®. However, we could found out the mechanism in detail of seven of them. Information about Cascade®, Magellan ® and Smart-prepr® kits was not enough. Conclusion: The review provided the main PRP extraction devices available with CE marking and its distinguishing characteristics, however, it is crucial to pay attention to PRP extraction procedure and administration, to guarantee the final product quality. Pharmacy Department must get involved in the device selections due to the close link with the manufactured drug quality. Working together with the AEMPS will contribute to defining extraction procedure specifically.

Data-Sharing Method for Multi-Smart Devices at Close Range

Directory of Open Access Journals (Sweden)

Myoungbeom Chung

2015-01-01

Full Text Available We proposed a useful data-sharing method among multi-smart devices at close range using inaudible frequencies and Wi-Fi. The existing near data-sharing methods mostly use Bluetooth technology, but these methods have the problem of being unable to be operated using different operating systems. To correct this flaw, the proposed method that uses inaudible frequencies through the inner speaker and microphone of smart device can solve the problems of the existing methods. Using the proposed method, the sending device generates trigger signals composed of inaudible sound. Moreover, smart devices that receive the signals obtain the shared data from the sending device through Wi-Fi. To evaluate the efficacy of the proposed method, we developed a near data-sharing application based on the trigger signals and conducted a performance evaluation experiment. The success rate of the proposed method was 98.8%. Furthermore, we tested the user usability of the Bump application and the proposed method and found that the proposed method is more useful than Bump. Therefore, the proposed method is an effective approach for sharing data practically among multi-smart devices at close range.

Properties of plasma sheath with ion temperature in magnetic fusion devices

International Nuclear Information System (INIS)

Liu Jinyuan; Wang Feng; Sun Jizhong

2011-01-01

The plasma sheath properties in a strong magnetic field are investigated in this work using a steady state two-fluid model. The motion of ions is affected heavily by the strong magnetic field in fusion devices; meanwhile, the effect of ion temperature cannot be neglected for the plasma in such devices. A criterion for the plasma sheath in a strong magnetic field, which differs from the well-known Bohm criterion for low temperature plasma sheath, is established theoretically with a fluid model. The fluid model is then solved numerically to obtain detailed sheath information under different ion temperatures, plasma densities, and magnetic field strengths.

Plasma response to electron energy filter in large volume plasma device

International Nuclear Information System (INIS)

Sanyasi, A. K.; Awasthi, L. M.; Mattoo, S. K.; Srivastava, P. K.; Singh, S. K.; Singh, R.; Kaw, P. K.

2013-01-01

An electron energy filter (EEF) is embedded in the Large Volume Plasma Device plasma for carrying out studies on excitation of plasma turbulence by a gradient in electron temperature (ETG) described in the paper of Mattoo et al. [S. K. Mattoo et al., Phys. Rev. Lett. 108, 255007 (2012)]. In this paper, we report results on the response of the plasma to the EEF. It is shown that inhomogeneity in the magnetic field of the EEF switches on several physical phenomena resulting in plasma regions with different characteristics, including a plasma region free from energetic electrons, suitable for the study of ETG turbulence. Specifically, we report that localized structures of plasma density, potential, electron temperature, and plasma turbulence are excited in the EEF plasma. It is shown that structures of electron temperature and potential are created due to energy dependence of the electron transport in the filter region. On the other hand, although structure of plasma density has origin in the particle transport but two distinct steps of the density structure emerge from dominance of collisionality in the source-EEF region and of the Bohm diffusion in the EEF-target region. It is argued and experimental evidence is provided for existence of drift like flute Rayleigh-Taylor in the EEF plasma

Ionization effects and linear stability in a coaxial plasma device

Science.gov (United States)

Kurt, Erol; Kurt, Hilal; Bayhan, Ulku

2009-03-01

A 2-D computer simulation of a coaxial plasma device depending on the conservation equations of electrons, ions and excited atoms together with the Poisson equation for a plasma gun is carried out. Some characteristics of the plasma focus device (PF) such as critical wave numbers a c and voltages U c in the cases of various pressures Pare estimated in order to satisfy the necessary conditions of traveling particle densities ( i.e. plasma patterns) via a linear analysis. Oscillatory solutions are characterized by a nonzero imaginary part of the growth rate Im ( σ) for all cases. The model also predicts the minimal voltage ranges of the system for certain pressure intervals.

Presheath profiles in simulated tokamak edge plasmas

International Nuclear Information System (INIS)

LaBombard, B.; Conn, R.W.; Hirooka, Y.; Lehmer, R.; Leung, W.K.; Nygren, R.E.; Ra, Y.; Tynan, G.

1988-04-01

The PISCES plasma surface interaction facility at UCLA generates plasmas with characteristics similar to those found in the edge plasmas of tokamaks. Steady state magnetized plasmas produced by this device are used to study plasma-wall interaction phenomena which are relevant to tokamak devices. We report here progress on some detailed investigations of the presheath region that extends from a wall surface into these /open quotes/simulated tokamak/close quotes/ edge plasma discharges along magnetic field lines

Thin low Z coatings for plasma devices

International Nuclear Information System (INIS)

Norem, J.; Bowers, D.A.

1978-05-01

Coating the walls of the vacuum chamber with beryllium or some other low Z material has been proposed as a possible means of solving the problems of high Z influx into plasmas. We attempt to demonstrate that very thin, low Z coatings are compatible with the operation of plasma devices and beneficial to plasma performance. We determine that the thickness of coating material required is only about 10 monolayers. In a radiation environment, radiation-induced solute segregation should help to maintain the integrity of such thin coatings against diffusion and other processes. We discuss the properties of these thin coatings and possible means of in situ application and maintenance. Since deposition of plasma impurities on the walls will occur anyway, we discuss injection of solid pellets into the plasma as a direct way of introducing impurities which would ultimately serve as coating material

Beam acceleration in plasma focus device

Energy Technology Data Exchange (ETDEWEB)

Antanasijevic, R.; Banjanac, R.; Dragic, A.; Maric, Z.; Stanojevic, J.; Udovicic, V. E-mail: udovicic@atom.phy.bg.ac.yu; Vukovic, J

2001-06-01

The proton beam emission from the small 8 kJ plasma focus device operated with the H{sub 2} filling was analyzed. Maximum energy and yield were obtained using NTD. The fast protons were registered with the energy up to 500 keV using the polycarbonate absorbers with the different thickness.

Beam acceleration in plasma focus device

International Nuclear Information System (INIS)

Antanasijevic, R.; Banjanac, R.; Dragic, A.; Maric, Z.; Stanojevic, J.; Udovicic, V.; Vukovic, J.

2001-01-01

The proton beam emission from the small 8 kJ plasma focus device operated with the H 2 filling was analyzed. Maximum energy and yield were obtained using NTD. The fast protons were registered with the energy up to 500 keV using the polycarbonate absorbers with the different thickness

Dual-function magnetic structure for toroidal plasma devices

International Nuclear Information System (INIS)

Brown, R.L.

1978-01-01

This invention relates to a support system wherein the iron core and yoke of the plasma current system of a tokamak plasma containment device is redesigned to support the forces of the magnet coils. The containment rings, which occupy very valuable space around the magnet coils, are utilized to serve as yokes for the core such that the conventional yoke is eliminated. The overall result is an improved aspect ratio, reduction in structure, smaller overall size, and improved access to the plasma ring

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

Electrical characteristics of a small plasma focus device

International Nuclear Information System (INIS)

Choi, P.; Favre, M.; Silva, P.; Chuaqui, H.; Wyndham, E.

1996-01-01

Efficient plasma focus operation relies on uniform initial breakdown across the insulator surface. The basic plasma focus electric circuit is discussed in order to highlight circuit modifications that produce high voltage oscillation at the initial breakdown time. Superimposed on the main discharge voltage, such oscillating voltage has been found in real systems to enhance the initial gas breakdown by localizing the initial current path across the insulator surface. PSPICE circuit simulations are compared with electric signals from different operational plasma focus devices. (author). 3 figs., 7 refs

Numerical Experiments Providing New Insights into Plasma Focus Fusion Devices

Directory of Open Access Journals (Sweden)

Sing Lee

2010-04-01

Full Text Available Recent extensive and systematic numerical experiments have uncovered new insights into plasma focus fusion devices including the following: (1 a plasma current limitation effect, as device static inductance is reduced towards very small values; (2 scaling laws of neutron yield and soft x-ray yield as functions of storage energies and currents; (3 a global scaling law for neutron yield as a function of storage energy combining experimental and numerical data showing that scaling deterioration has probably been interpreted as neutron ‘saturation’; and (4 a fundamental cause of neutron ‘saturation’. The ground-breaking insights thus gained may completely change the directions of plasma focus fusion research.

Pulsed Plasma Lubrication Device and Method

Science.gov (United States)

Hofer, Richard R. (Inventor); Bickler, Donald B. (Inventor); D'Agostino, Saverio A. (Inventor)

2016-01-01

Disclosed herein is a lubrication device comprising a solid lubricant disposed between and in contact with a first electrode and a second electrode dimensioned and arranged such that application of an electric potential between the first electrode and the second electrode sufficient to produce an electric arc between the first electrode and the second electrode to produce a plasma in an ambient atmosphere at an ambient pressure which vaporizes at least a portion of the solid lubricant to produce a vapor stream comprising the solid lubricant. Methods to lubricate a surface utilizing the lubrication device in-situ are also disclosed.

On the spatial behavior of background plasma in different background pressure in CPS device

International Nuclear Information System (INIS)

Samantaray, Subrata; Paikaray, Rita; Sahoo, Gourishankar; Das, Parthasarathi; Ghosh, Joydeep; Sanyasi, Amulya Kumar

2015-01-01

Blob formation and transport is a major concern for investigators as it greatly reduces the efficiency of the devices. Initial results from CPS device confirm the role of fast neutrals inside the bulk plasma in the process of blob formation and transport. 2-D simulation of curvature and velocity shear instability in plasma structures suggest that in the presence of background plasma, secondary instability do not grow non-linearly to a high level and stabilizes the flow. Adiabaticity effect also creates a radial barrier for interchange modes. In the absence of background plasma the blob fragments even at the modest level of viscosity. The fast neutrals outside bulk plasma supposed to stabilize the system. The background plasma set up is aimed at creating fast neutrals outside main plasma column, hence; the background plasma set up is done in CPS device. The spatial behavior of plasma column in between electrodes is different for different base pressure in CPS device. The spatial variation of electron temperature of plasma column between electrodes is presented in this communication. Electron temperature is measured from emission spectroscopy data. The maximum electron temperature (line averaged) is ∼ 1.5 eV. (author)

A comprehensive study of electrostatic turbulence and transport in the laboratory basic plasma device TORPEX

Science.gov (United States)

Furno, I.; Fasoli, A.; Avino, F.; Bovet, A.; Gustafson, K.; Iraji, D.; Labit, B.; Loizu, J.; Ricci, P.; Theiler, C.

2012-04-01

TORPEX is a toroidal device located at the CRPP-EPFL in Lausanne. In TORPEX, a vertical magnetic field superposed on a toroidal field creates helicoidal field lines with both ends terminating on the torus vessel. The turbulence driven by magnetic curvature and plasma gradients causes plasma transport in the radial direction while at the same time plasma is progressively lost along the field lines. The relatively simple magnetic geometry and diagnostic access of the TORPEX configuration facilitate the experimental study of low frequency instabilities and related turbulent transport, and make an accurate comparison between simulations and experiments possible. We first present a detailed investigation of electrostatic interchange turbulence, associated structures and their effect on plasma using high-resolution diagnostics of plasma parameters and wave fields throughout the whole device cross-section, fluid models and numerical simulations. Interchange modes nonlinearly develop blobs, radially propagating filaments of enhanced plasma pressure. Blob velocities and sizes are obtained from probe measurements using pattern recognition and are described by an analytical expression that includes ion polarization currents, parallel sheath currents and ion-neutral collisions. Then, we describe recent advances of a non-perturbative Li 6+ miniaturized ion source and a detector for the investigation of the interaction between supra thermal ions and interchange-driven turbulence. We present first measurements of the spatial and energy space distribution of the fast ion beam in different plasma scenarios, in which the plasma turbulence is fully characterized. The experiments are interpreted using two-dimensional fluid simulations describing the low-frequency interchange turbulence, taking into account the plasma source and plasma losses at the torus vessel. By treating fast ions as test particles, we integrate their equations of motion in the simulated electromagnetic fields, and

Chaos control and taming of turbulence in plasma devices

DEFF Research Database (Denmark)

Klinger, T.; Schröder, C.; Block, D.

2001-01-01

Chaos and turbulence are often considered as troublesome features of plasma devices. In the general framework of nonlinear dynamical systems, a number of strategies have been developed to achieve active control over complex temporal or spatio-temporal behavior. Many of these techniques apply...... to plasma instabilities. In the present paper we discuss recent progress in chaos control and taming of turbulence in three different plasma "model" experiments: (1) Chaotic oscillations in simple plasma diodes, (2) ionization wave turbulence in the positive column of glow discharges, and (3) drift wave...

Plasma surface interactions in controlled fusion devices

Energy Technology Data Exchange (ETDEWEB)

Ghendrih, Ph.; Becoulet, M.; Costanzo, L. [and others

2000-07-01

This report brings together all the contributions of EURATOM/CEA association to the 14. international conference on plasma surface interactions in controlled fusion devices. 24 papers are presented and they deal mainly with the ergodic divertor and the first wall of Tore-supra tokamak.

Plasma surface interactions in controlled fusion devices

International Nuclear Information System (INIS)

Ghendrih, Ph.; Becoulet, M.; Costanzo, L.

2000-07-01

This report brings together all the contributions of EURATOM/CEA association to the 14. international conference on plasma surface interactions in controlled fusion devices. 24 papers are presented and they deal mainly with the ergodic divertor and the first wall of Tore-supra tokamak

Plasma position and shape control device for thermonuclear device

International Nuclear Information System (INIS)

Takeuchi, Kazuhiro; Abe, Mitsushi; Kinoshita, Shigemi.

1993-01-01

A plasma position and shape control system is constituted with a measuring device, a quenching probability calculation section and a control calculation section. A quenching probability is calculated in the quenching probability calculation section by using a measuring data on temperature, electric current and magnetic field of superconductive coils, based on a margin upto a limit value. The control calculation section selects a control method which decreases applied voltage or current instruction value as the quenching probability of the coils is higher. Since the quenching probability of the superconductive coils can be forecast and a state of low quenching danger can be selected, the safety of the device is improved. When the quenching danger is allowed to a predetermined value, a wide operation region can be provided. (N.H.)

Microcavity Plasma Devices and Arrays Fabricated in Semiconductor, Ceramic, or Metal/polymer Structures: A New Realm of Plasma Physics and Photonics Applications

International Nuclear Information System (INIS)

Eden, J. G.

2005-01-01

Micro discharge, or microcavity plasma, is the broad term that has come to be associated with an emerging class of glow discharge devices in which the characteristic spatial dimension of the plasma is nominally ) dia. Si wafers and operated in the rare gases and Ar/N2 gas mixtures. Also, photodetection in the ultraviolet, visible and near-infrared with microplasma devices has been observed by interfacing a low temperature plasma with a semiconductor. Carbon nanotubes grown directly within the microcavity of microplasma devices improve all key performance parameters of the device, and nanoporous Al2O3 grown onto Al by wet chemical processing yields microplasma devices of exceptional stability and lifetime. The opportunities such structures offer for accessing new avenues in plasma physics and photonics will be discussed. (Author)

Current and Perspective Applications of Dense Plasma Focus Devices

Science.gov (United States)

Gribkov, V. A.

2008-04-01

Dense Plasma Focus (DPF) devices' applications, which are intended to support the main-stream large-scale nuclear fusion programs (NFP) from one side (both in fundamental problems of Dense Magnetized Plasma physics and in its engineering issues) as well as elaborated for an immediate use in a number of fields from the other one, are described. In the first direction such problems as self-generated magnetic fields, implosion stability of plasma shells having a high aspect ratio, etc. are important for the Inertial Confinement Fusion (ICF) programs (e.g. as NIF), whereas different problems of current disruption phenomenon, plasma turbulence, mechanisms of generation of fast particles and neutrons in magnetized plasmas are of great interest for the large devices of the Magnetic Plasma Confinement—MPC (e.g. as ITER). In a sphere of the engineering problems of NFP it is shown that in particular the radiation material sciences have DPF as a very efficient tool for radiation tests of prospect materials and for improvement of their characteristics. In the field of broad-band current applications some results obtained in the fields of radiation material sciences, radiobiology, nuclear medicine, express Neutron Activation Analysis (including a single-shot interrogation of hidden illegal objects), dynamic non-destructive quality control, X-Ray microlithography and micromachining, and micro-radiography are presented. As the examples of the potential future applications it is proposed to use DPF as a powerful high-flux neutron source to generate very powerful pulses of neutrons in the nanosecond (ns) range of its duration for innovative experiments in nuclear physics, for the goals of radiation treatment of malignant tumors, for neutron tests of materials of the first wall, blankets and NFP device's constructions (with fluences up to 1 dpa per a year term), and ns pulses of fast electrons, neutrons and hard X-Rays for brachytherapy.

Current and Perspective Applications of Dense Plasma Focus Devices

International Nuclear Information System (INIS)

Gribkov, V. A.

2008-01-01

Dense Plasma Focus (DPF) devices' applications, which are intended to support the main-stream large-scale nuclear fusion programs (NFP) from one side (both in fundamental problems of Dense Magnetized Plasma physics and in its engineering issues) as well as elaborated for an immediate use in a number of fields from the other one, are described. In the first direction such problems as self-generated magnetic fields, implosion stability of plasma shells having a high aspect ratio, etc. are important for the Inertial Confinement Fusion (ICF) programs (e.g. as NIF), whereas different problems of current disruption phenomenon, plasma turbulence, mechanisms of generation of fast particles and neutrons in magnetized plasmas are of great interest for the large devices of the Magnetic Plasma Confinement--MPC (e.g. as ITER). In a sphere of the engineering problems of NFP it is shown that in particular the radiation material sciences have DPF as a very efficient tool for radiation tests of prospect materials and for improvement of their characteristics. In the field of broad-band current applications some results obtained in the fields of radiation material sciences, radiobiology, nuclear medicine, express Neutron Activation Analysis (including a single-shot interrogation of hidden illegal objects), dynamic non-destructive quality control, X-Ray microlithography and micromachining, and micro-radiography are presented. As the examples of the potential future applications it is proposed to use DPF as a powerful high-flux neutron source to generate very powerful pulses of neutrons in the nanosecond (ns) range of its duration for innovative experiments in nuclear physics, for the goals of radiation treatment of malignant tumors, for neutron tests of materials of the first wall, blankets and NFP device's constructions (with fluences up to 1 dpa per a year term), and ns pulses of fast electrons, neutrons and hard X-Rays for brachytherapy

Experimental studies of plasma confinement in toroidal systems

International Nuclear Information System (INIS)

Bodin, H.A.B.; Keen, B.E.

1977-01-01

In this article the closed-line magnetic field approach to the plasma isolation and confinement problem in toroidal systems is reviewed. The theoretical aspects of closed-line magnetic field systems, indicating that topologically such systems are toroidal, are surveyed under the headings; topology of closed-line systems, equilibrium in different configurations and classification of toroidal devices, MHD stability, non-ideal effects in MHD stability, microscopic stability, and plasma energy loss. A section covering the experimental results of plasma confinement in toroidal geometry considers Stellerators, Tokamaks, toroidal pinch -the reversed-field pinch, screw pinches and high-β Tokamaks, Levitrons and multipoles (internal-ring devices), and miscellaneous toroidal containment devices. Recent achievements and the present position are discussed with reference to the status of Tokamak research, low-β stellerator research and high-β research. It is concluded from the continuing progress made in this research that the criteria for the magnetic containment of plasmas can be met. Further, it is concluded that the construction of a successful and economic fusion reactor is within the scope of advancing science and technology. 250 references. (U.K.)

Experimental studies of plasma confinement in toroidal systems

Energy Technology Data Exchange (ETDEWEB)

Bodin, H A.B.; Keen, B E [UKAEA, Abingdon. Culham Lab.

1977-12-01

In this article the closed-line magnetic field approach to the plasma isolation and confinement problem in toroidal systems is reviewed. The theoretical aspects of closed-line magnetic field systems, indicating that topologically such systems are toroidal, are surveyed under the headings; topology of closed-line systems, equilibrium in different configurations and classification of toroidal devices, MHD stability, non-ideal effects in MHD stability, microscopic stability, and plasma energy loss. A section covering the experimental results of plasma confinement in toroidal geometry considers Stellerators, Tokamaks, toroidal pinch -the reversed-field pinch, screw pinches and high-..beta.. Tokamaks, Levitrons and multipoles (internal-ring devices), and miscellaneous toroidal containment devices. Recent achievements and the present position are discussed with reference to the status of Tokamak research, low-..beta.. stellerator research and high-..beta.. research. It is concluded from the continuing progress made in this research that the criteria for the magnetic containment of plasmas can be met. Further, it is concluded that the construction of a successful and economic fusion reactor is within the scope of advancing science and technology. 250 references.

Characterisation of a micro-plasma device sensor using electrical measurements and emission spectroscopy

International Nuclear Information System (INIS)

Mariotti, D.

2002-04-01

This thesis reports on research undertaken on the characterisation of a micro-plasma device to be used for gas analysis by mean of plasma emission spectroscopy. The work covers aspects related to the micro-plasma electrical and optical emission parameters, and their importance for the utilisation of the micro-plasma device in gas analysis. Experimental results have been used to analyse the fundamental micro-plasma processes and to develop a model, which could provide additional information. This dissertation contains a general literature review of topics related to plasma physics, plasma emission spectroscopy, gas analysis (chemical analysis and artificial olfaction) and other micro-plasma applications. Experimental work focuses on two main areas: electrical measurements and emission measurements. Firstly, electrical measurements are taken and interpretations are given. Where necessary, new theoretical treatments are suggested in order to describe better the physical phenomena. Plasma emission has been considered under different working conditions. This allowed the characterisation of the micro-plasma emission and also a better understanding of the micro-plasma processes. On the basis of the experimental data obtained and other assumptions a model has been developed. A computer simulation based on this model provided additional useful information on the micro- plasma behaviour. The first fundamental implication of this new research is the peculiar behaviour of the micro-plasma. This micro-plasma exhibited deviations from Paschen law and strong dependency on cathode material, which contributed to the formation of a low current stable regime. These results have been followed by physical interpretations and theoretical descriptions. The second implication is the establishment of the boundaries and of the influencing parameters for plasma emission spectroscopy as an analytical tool in this particular micro-plasma. From the applied perspective this study has shown that

MAGNETIC END CLOSURES FOR PLASMA CONFINING AND HEATING DEVICES

Science.gov (United States)

Post, R.F.

1963-08-20

More effective magnetic closure field regions for various open-ended containment magnetic fields used in fusion reactor devices are provided by several spaced, coaxially-aligned solenoids utilized to produce a series of nodal field regions of uniform or, preferably, of incrementally increasing intensity separated by lower intensity regions outwardly from the ends of said containment zone. Plasma sources may also be provided to inject plasma into said lower intensity areas to increase plasma density therein. Plasma may then be transported, by plasma diffusion mechanisms provided by the nodal fields, into the containment field. With correlated plasma densities and nodal field spacings approximating the mean free partl cle collision path length in the zones between the nodal fields, optimum closure effectiveness is obtained. (AEC)

Extension of operation regimes and investigation of three-dimensional current-less plasmas in the Large Helical Device

International Nuclear Information System (INIS)

Kaneko, O.

2012-11-01

The Large Helical Device (LHD) has shown the advantages of heliotron plasma for fusion reactor from operational point of view not only such as disruption free and steady state operation, but also as high density and stable high beta operation. Since the last Fusion Energy Conference in Daejon in 2010 (Yamada, 2011 Nucl. Fusion 51 094021), physical understanding as well as parameter improvement of net-current free helical plasmas has progressed successively. The current efforts are focused on optimization of plasma edge condition to extend the operation regime towards higher ion temperature and more stable high density. In LHD a part of open helical divertors are being modified to the baffle-structured closed ones to aim at active control of the edge plasma. It has been demonstrated that the neutral pressure in the closed helical divertor was more than 10 times higher than that in the open helical divertor. The central ion temperature has exceeded 7 keV. This high-T i plasma was obtained by a carbon pellet injection and the kinetic-energy confinement was improved by a factor of 1.5. Transport analysis of the high-T i plasmas has shown that the ion-thermal conductivity and the viscosity reduced after the pellet injection. Study of physics in 3-D geometry is highlighted in the topics of the response to Resonant Magnetic Perturbation such as ELM mitigation and divertor detachment. Novel approaches of non-local and non-diffusive transport have also been advanced. In this paper, highlighted results in these two years are overviewed. (author)

Particle supply and recovery device

International Nuclear Information System (INIS)

Yamada, Kimio; Okazaki, Takashi.

1988-01-01

This invention concerns a particle supply and recovery device suitable to the supply of fuels and exhaustion of reaction products in a tokamak device. The divertor chamber is divided into an inner side and an outer side, in which only the outer side is constituted as a tightly closed structure. Particles are supplied from the inside of main plasmas and exhausted from the outer side of the divertor chamber. In the divertor equilibrium arrangement, particles escaping from the main plasmas are conveyed mainly passing through the outer side scrape-off layer to the divertor chamber. The particle density is higher at the outer side and lower at the inner side of the scrape-off layer. By making the outer side as a tightly closed structure, the pressure is increased and the particle exhaustion efficiency is improved. Since the particle density is low in the inner scrape-layer, the particle supply efficiency to the main plasma is increased by supplying the particles from the inside. Further, particles ionized in the inner scrape-off layer are returned to the main plasma chamber and then supplied again since the inner divertor chamber is not closed. Accordingly, the particle supply efficiency can further be improved. (K.M.)

Density profile measurements from a two-gun plasma focus device

International Nuclear Information System (INIS)

Tzeng, C.C.; Yen, C.K.; Yeh, T.R.; Kuo, Y.Y.; Shang, D.J.; Yu, Y.Z.; Hou, W.S.

1990-01-01

The dynamics of the plasma evolution in a two-gun plasma focus device has been studied using the laser shadowgraphy as well as the laser interferometry. The experiments were carried out from a 700 kJ two-gun plasma focus device reported earlier, which consisted of a pair of Mather type coaxial electrodes connected muzzle to muzzle. Previous results indicated that the simultaneous formation of the two deuterium plasma foci occurred earlier and then after ∼ 100 ns a disk-shaped plasma of ∼ 1.5 cm in diameter appeared in the middle region between the anodes. It is, therefore, the authors' goal to study the density profiles in the plasma foci and the middle region in order to understand further the formation of the plasma foci and their time evolution. The laser shadowgraphy was done with a XeCl excimer pumped dye laser system which operated at 550 nm with pulse width of ∼ 10 ns. The laser interferometry, on the other hand, was carried out using a TEA-TEA oscillator-amplifier N 2 -laser system with 337.1 nm and subnano-second pulse width. Both results show that the maximum electron density is ≥2 x 10 19 cm -3 and, in addition, the growth of the hydrodynamic instabilities are observed. These results together with the detailed density profiles are presented and discussed

Advanced 65 nm CMOS devices fabricated using ultra-low energy plasma doping

International Nuclear Information System (INIS)

Walther, S.; Lenoble, D.; Lallement, F.; Grouillet, A.; Erokhin, Y.; Singh, V.; Testoni, A.

2005-01-01

For leading edge CMOS and DRAM technologies, plasma doping (PLAD) offers several unique advantages over conventional beamline implantation. For ultra-low energy source and drain extensions (SDE), source drain contact and high dose poly doping implants PLAD delivers 2-5x higher throughput compared to beamline implanters. In this work we demonstrate process performance and process integration benefits enabled by plasma doping for advanced 65 nm CMOS devices. Specifically, p + /n ultra-shallow junctions formed with BF 3 plasma doping have superior X j /R s characteristics to beamline implants and yield up to 30% lower R s for 20 nm X j while using standard spike anneal with ramp-up rate of 75 deg. C/s. These results indicate that PLAD could extend applicability of standard spike anneal by at least one technology node past 65 nm. A CMOS split lot has been run to investigate process integration advantages unique to plasma doping and to determine CMOS device characteristics. Device data measured on 65 nm transistors fabricated with offset spacers indicate that devices with SDE formed by plasma doping have superior V t roll-off characteristics arguably due to improved lateral gate-overlap of PLAD SDE junctions. Furthermore, offset spacers could be eliminated in 65 nm devices with PLAD SDE implants while still achieving V t roll-off and I on -I off performance at least equivalent to control devices with offset spacers and SDE formed by beamline implantation. Thus, another advantage of PLAD is simplified 65 nm CMOS manufacturing process flow due to elimination of offset spacers. Finally, we present process transfer from beamline implants to PLAD for several applications, including SDE and gate poly doping with very high productivity

Construction and characterization of a plasma focus device and diagnostic test ion

International Nuclear Information System (INIS)

Morales Arango, Diana Marsela

2013-01-01

In this work we designed and built a Plasma Focus device 2kJ power in order to extend the energy range of devices designed in DPTN CCHEN and study the scaling laws type Plasma Focus Device. The operating parameters of this device are: T/ 4 =907ns, C = 8000nF, L = 42nH, E = 2kJ, lo = 276kA. In such a way to optimize the device tests were performed with various electrode configurations, insulator length, to determine the conditions under which it operates in Plasma Focus mode. Subsequent to the construction tests were performed on devices PF-400J (T /4 = 300ns, C = 880nF, L = 38nH, E = 400J, lo = 168kA) y PF-2kJ (device between the hundreds of joules and kilojoules of energy) diagnostic charged particle emission used the Faraday Cup consisting of a biased graphite collector. For a series of shots on the PF-400J and PF-2kJ operated at 27kV and 20kV respectively kinetic energy distribution of proton between 60keV-150keV were found, deuterons between 60KeV-300KeV. With the idea of optimizing the results in future diagnostic type spectrometer Thompson, spectroscopy and diffraction networks in gas mixture will be implemented

Plasma device

International Nuclear Information System (INIS)

Thode, L.E.

1981-01-01

A method is described for electron beam heating of a high-density plasma to drive a fast liner. An annular or solid relativistic electron beam is used to heat a plasma to kilovolt temperatures through streaming instabilities in the plasma. Energy deposited in the plasma then converges on a fast liner to explosively or ablatively drive the liner to implosion. (U.K.)

Measurements of plasma termination in ICRF heated long pulse discharges with fast framing cameras in the Large Helical Device

International Nuclear Information System (INIS)

Shoji, Mamoru; Kasahara, Hiroshi; Tanaka, Hirohiko

2015-01-01

The termination process of long pulse plasma discharges in the Large Helical Device (LHD) have been observed with fast framing cameras, which shows that the reason for the termination of the discharged has been changed with increased plasma heating power, improvements of plasma heating systems and change of the divertor configuration, etc. For long pulse discharges in FYs2010-2012, the main reason triggering the plasma termination was reduction of ICRF heating power with rise of iron ion emission due to electric breakdown in an ICRF antenna. In the experimental campaign in FY2013, the duration time of ICRF heated long pulse plasma discharges has been extended to about 48 minutes with a plasma heating power of ∼1.2 MW and a line-averaged electron density of ∼1.2 × 10"1"9 m"-"3. The termination of the discharges was triggered by release of large amounts of carbon dusts from closed divertor regions, indicating that the control of dust formation in the divertor regions is indispensable for extending the duration time of long pulse discharges. (author)

Sausage instability of Z-discharged plasma channel in LIB-fusion device

International Nuclear Information System (INIS)

Murakami, H.; Kawata, S.; Niu, K.

1982-07-01

Current-carring plasma channels have been proposed for transporting intense ion beams from diodes to a target in a LIB-fusion device. In this paper, the growth rate of the most dangerous surface mode, that is, axisymmetric sausage instability is examined for the plasma channel. The growth rate is shown to be smaller than that of the plasma channel with no fluid motion in a sharp boundary. It is concluded that the stable plasma channel can be formed. (author)

StarClose Vascular Closure Device: Prospective Study on 222 Deployments in an Interventional Radiology Practice

International Nuclear Information System (INIS)

Imam, Atique; Carter, Ranjana M. S.; Phillips-Hughes, Jane; Boardman, Philip; Uberoi, Raman

2007-01-01

The StarClose device (Abbott Vascular Devices; Abbott Laboratories, Redwood City, CA) utilizes an externally placed Nitinol clip to achieve arterial closure following femoral artery puncture. The objectives of this study were to assess the efficacy and complications of the StarClose device in patients undergoing interventional radiological procedures. Preprocedural clotting status, pulse and blood pressure, severity of vessel calcification, sheath size, and time to deployment were recorded. Postdeployment complications immediately postprocedure, at 1 h, at 2 h, and at 1 week were recorded. A duplex scan was performed in the first 10 patients to assess any immediate vascular complications. Deployments were successful in 96% achieving immediate hemostasis. Mean deployment time was 48 s. There were no major complications. The StarClose device was found to have a high technical and clinical efficacy

Plasma device

International Nuclear Information System (INIS)

Thode, L.E.

1981-01-01

A method is described of providing electron beam heating of a high-density plasma to drive a fast liner to implode a structured microsphere. An annular relativistic electron beam is used to heat an annular plasma to kilovolt temperatures through streaming instabilities in the plasma. Energy deposited in the annular plasma then converges on a fast liner to explosively or ablatively drive the liner to convergence to implode the structured microsphere. (U.K.)

dc-plasma-sprayed electronic-tube device

Science.gov (United States)

Meek, T.T.

1982-01-29

An electronic tube and associated circuitry which is produced by dc plasma arc spraying techniques is described. The process is carried out in a single step automated process whereby both active and passive devices are produced at very low cost. The circuitry is extremely reliable and is capable of functioning in both high radiation and high temperature environments. The size of the electronic tubes produced are more than an order of magnitude smaller than conventional electronic tubes.

MHD instabilities and their effects on plasma confinement in the large helical device plasmas

International Nuclear Information System (INIS)

Toi, K.

2002-01-01

MHD stability of NBI heated plasmas and impacts of MHD modes on plasma confinement are intensively studied in the Large Helical Device (LHD). Three characteristic MHD instabilities were observed, that is, (1) pressure driven modes excited in the plasma edge, (2) pressure driven mode in the plasma core, and (3) Alfven eigenmodes (AEs) driven by energetic ions. MHD mode excited in the edge region accompanies multiple satellites, and is called Edge Harmonic Modes (EHMs). EHM sometimes has a bursting character. The bursting EHM transiently decreases the stored energy by about 15 percent. In the plasma core region, m=2/n=1 pressure driven mode is typically destabilized. The mode often induces internal collapse in the higher beta regime more than 1 percent. The internal collapse appreciably affects the global confinement. Energetic ion driven AEs are often detected in NBI-heated LHD plasmas. Particular AE with the frequency 8-10 times larger than TAE-frequency was detected in high beta plasmas more than 2 percent. The AE may be related to helicity-induced AE. Excitation of these three types of MHD instabilities and their impacts on plasma confinement are discussed. (author)

Plasma device

International Nuclear Information System (INIS)

Thode, L.E.

1981-01-01

A relativistic electron beam generator or accelerator produces a high-voltage electron beam which is modulated to initiate electron bunching within the beam which is then applied to a high-density target plasma which typically comprises DT, DD, or similar thermonuclear gas at a density of 10 17 to 10 20 electrons per cubic centimeter. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region of the high-density plasma target. The high-temperature plasma can be used to heat a high Z material to generate radiation. Alternatively, a tunable radiation source is produced by using a moderate Z gas or a mixture of high Z and low Z gas as the target plasma. (author)

Plasma processing of soft materials for development of flexible devices

International Nuclear Information System (INIS)

Setsuhara, Yuichi; Cho, Ken; Takenaka, Kosuke; Shiratani, Masaharu; Sekine, Makoto; Hori, Masaru

2011-01-01

Plasma-polymer interactions have been studied as a basis for development of next-generation processing of flexible devices with soft materials by means of low-damage plasma technologies (soft materials processing technologies). In the present article, interactions between argon plasmas and polyethylene terephthalate (PET) films have been examined for investigations of physical damages induced by plasma exposures to the organic material via chemical bonding-structure analyses using hard X-ray photoelectron spectroscopy (HXPES) together with conventional X-ray photoelectron spectroscopy (XPS). The PET film has been selected as a test material for investigations in the present study not merely because of its specific applications, such as a substrate material, but because PET is one of the well defined organic materials containing major components in a variety of functional soft materials; C-C main chain, CH bond, oxygen functionalities (O=C-O bond and C-O bond) and phenyl group. Especially, variations of the phenyl group due to argon plasma exposures have been investigated in the present article in order to examine plasma interactions with π-conjugated system, which is in charge of electronic functions in many of the π-conjugated electronic organic materials to be utilized as functional layer for advanced flexible device formations. The PET films have been exposed to argon plasmas sustained via inductive coupling of RF power with low-inductance antenna modules. The HXPES analyses exhibited that the degradations of the oxygen functionalities and the phenyl group in the deeper regions up to 50 nm from the surface of the samples were insignificant indicating that the bond scission and/or the degradations of the chemical bonding structures due to photoirradiation from the plasma and/or surface heating via plasma exposure were relatively insignificant as compared with damages in the vicinity of the surface layers.

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)

Surface ionization wave in a plasma focus-like model device

International Nuclear Information System (INIS)

Yordanov, V; Blagoev, A; Ivanova-Stanik, I; Veldhuizen, E M van; Nijdam, S; Dijk, J van; Mullen, J J A M van der

2008-01-01

A numerical particle in cell-Monte Carlo model of the breakdown in the plasma focus device simulates the development of an ionization wave sliding along the insulator. In order to validate this model a planar model device is created. The pictures of the discharges taken by a fast optical camera show that we have qualitative agreement between the model and the experimental observations.

Surface ionization wave in a plasma focus-like model device

Energy Technology Data Exchange (ETDEWEB)

Yordanov, V; Blagoev, A [Faculty of Physics, University of Sofia, 5 James Bourchier Blvd, BG-1164, Sofia (Bulgaria); Ivanova-Stanik, I [IPPLM, 23 Hery St, PO Box 49, PL-00-908 Warsaw (Poland); Veldhuizen, E M van; Nijdam, S; Dijk, J van; Mullen, J J A M van der [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)], E-mail: v.yordanov@phys.uni-sofia.bg

2008-11-07

A numerical particle in cell-Monte Carlo model of the breakdown in the plasma focus device simulates the development of an ionization wave sliding along the insulator. In order to validate this model a planar model device is created. The pictures of the discharges taken by a fast optical camera show that we have qualitative agreement between the model and the experimental observations.

Production of radioisotopes within a plasma focus device

International Nuclear Information System (INIS)

Angeli, E.; Tartari, A.; Frignani, M.; Molinari, V.; Mostacci, D.; Rocchi, F.; Sumini, M. . E-mail address of corresponding author: domiziano.mostacci@mail.ing.unibo.it

2005-01-01

In recent years, research conducted in the US and in Italy has demonstrated production of radioisotopes in Plasma Focus (PF) devices, and particularly, on what could be termed 'endogenous' production, to wit, production within the plasma itself, as opposed to irradiation of targets. This technique relies on the formation of localized small plasma zones characterized by very high densities and fairly high temperatures. The conditions prevailing in these zones lead to high nuclear reaction rates, as pointed out in previous work by several authors. Further investigation of the cross sections involved has proven necessary to model the phenomena involved. In this paper, the present status of research in this field is reviewed, both with regards to cross section models and to experimental production of radioisotopes. Possible outcomes and further development are discussed. (author)

Construction of control and instrumentation devices of high voltage power supply of double chamber plasma nitrogen

International Nuclear Information System (INIS)

Saminto; Eko Priyono; Sugeng Riyanto

2013-01-01

A control and instrumentation devices of high voltage power supply of double chamber plasma nitrogen have been made. This device consists of the software and hardware component. Hardware component consists of SCR phase angle controller LPC-50HDA type, T100MD1616+ PLC, high voltage transformer and voltage rectifier system. Software component used a LADDER program and TBasic serves to control of the high voltage output. The components in these devices have been tested in the double chamber plasma nitrogen. Its performance meet with the design criteria that can supply of plasma nitrogen operation voltage in the range 290 Vdc to 851 Vdc with glow discharge current 0.4 A to 1.4 A. In general it can be said that the control and instrumentation devices of high voltage power supply is ready for use at the double chamber plasma nitrogen device. (author)

Critical plasma-wall interaction issues for plasma-facing materials and components in near-term fusion devices

International Nuclear Information System (INIS)

Federici, G.; Coad, J.P.; Haasz, A.A.; Janeschitz, G.; Noda, N.; Philipps, V.; Roth, J.; Skinner, C.H.; Tivey, R.; Wu, C.H.

2000-01-01

The increase in pulse duration and cumulative run-time, together with the increase of the plasma energy content, will represent the largest changes in operation conditions in future fusion devices such as the International Thermonuclear Experimental Reactor (ITER) compared to today's experimental facilities. These will give rise to important plasma-physics effects and plasma-material interactions (PMIs) which are only partially observed and accessible in present-day experiments and will open new design, operation and safety issues. For the first time in fusion research, erosion and its consequences over many pulses (e.g., co-deposition and dust) may determine the operational schedule of a fusion device. This paper identifies the most critical issues arising from PMIs which represent key elements in the selection of materials, the design, and the optimisation of plasma-facing components (PFCs) for the first-wall and divertor. Significant advances in the knowledge base have been made recently, as part of the R and D supporting the engineering design activities (EDA) of ITER, and some of the most relevant data are reviewed here together with areas where further R and D work is urgently needed

Modelling of plasma-antenna coupling and non-linear radio frequency wave-plasma-wall interactions in the magnetized plasma device under ion cyclotron range of frequencies

International Nuclear Information System (INIS)

Lu, LingFeng

2016-01-01

Ion Cyclotron Resonant Heating (ICRH) by waves in 30-80 MHz range is currently used in magnetic fusion plasmas. Excited by phased arrays of current straps at the plasma periphery, these waves exist under two polarizations. The Fast Wave tunnels through the tenuous plasma edge and propagates to its center where it is absorbed. The parasitically emitted Slow Wave only exists close to the launchers. How much power can be coupled to the center with 1 A current on the straps? How do the emitted radiofrequency (RF) near and far fields interact parasitically with the edge plasma via RF sheath rectification at plasma-wall interfaces? To address these two issues simultaneously, in realistic geometry over the size of ICRH antennas, this thesis upgraded and tested the Self-consistent Sheaths and Waves for ICH (SSWICH) code. SSWICH couples self-consistently RF wave propagation and Direct Current (DC) plasma biasing via non-linear RF and DC sheath boundary conditions (SBCs) at plasma/wall interfaces. Its upgrade is full wave and was implemented in two dimensions (toroidal/radial). New SBCs coupling the two polarizations were derived and implemented along shaped walls tilted with respect to the confinement magnetic field. Using this new tool in the absence of SBCs, we studied the impact of a density decaying continuously inside the antenna box and across the Lower Hybrid (LH) resonance. Up to the memory limits of our workstation, the RF fields below the LH resonance changed with the grid size. However the coupled power spectrum hardly evolved and was only weakly affected by the density inside the box. In presence of SBCs, SSWICH-FW simulations have identified the role of the fast wave on RF sheath excitation and reproduced some key experimental observations. SSWICH-FW was finally adapted to conduct the first electromagnetic and RF-sheath 2D simulations of the cylindrical magnetized plasma device ALINE. (author) [fr

Stability of axisymmetric plasmas in closed line magnetic fields

International Nuclear Information System (INIS)

Simakov, A.N.; Vernon Wong, H.; Berk, H.L.

2003-01-01

The stability of axisymmetric plasmas confined by closed poloidal magnetic field lines is considered. The results are relevant to plasmas in the dipolar fields of stars and planets, as well as the Levitated Dipole Experiment, multipoles, Z pinches and field reversed configurations. The ideal MHD energy principle is employed to study the stability of pressure driven shear Alfven modes. A point dipole is considered in detail to demonstrate that equilibria exist which are MHD stable for arbitrary beta. Effects of sound waves and plasma resistivity are investigated for Z pinch and point dipole equilibria by means of resistive MHD theory. Kinetic theory is used to study drift frequency modes and their interaction with MHD modes near the ideal stability boundary for different collisionality regimes. Effects of collisional dissipation on drift mode stability are explicitly evaluated and applied to a Z pinch. The role of finite Larmor radius effects and drift reversed particles in modifying ideal stability thresholds is examined. (author)

Experimental investigation on electrical characteristics and dose measurement of dielectric barrier discharge plasma device used for therapeutic application.

Science.gov (United States)

Shahbazi Rad, Zahra; Abbasi Davani, Fereydoun

2017-04-01

In this research, a Dielectric Barrier Discharge (DBD) plasma device operating in air has been made. The electrical characteristics of this device like instantaneous power, dissipated power, and discharge capacitance have been measured. Also, the effects of applied voltage on the dissipated power and discharge capacitance of the device have been investigated. The determination of electrical parameters is important in DBD plasma device used in living tissue treatment for choosing the proper treatment doses and preventing the destructive effects. The non-thermal atmospheric pressure DBD plasma source was applied for studying the acceleration of blood coagulation time, in vitro and wound healing time, in vivo. The citrated blood drops coagulated within 5 s treatment time by DBD plasma. The effects of plasma temperature and electric field on blood coagulation have been studied as an affirmation of the applicability of the constructed device. Also, the effect of constructed DBD plasma on wound healing acceleration has been investigated.

Measurements of ODAK-3K plasma device using plastic track detectors

International Nuclear Information System (INIS)

2010-01-01

In this study, some testing experiments on the fusion researches with a new-constructed plasma focus (PF) device, namely ODAK-3K are reported. The device has a maximal energy input of 3 kJ and is used for both plasma and D D reaction explorations. Experiments with deuterium have shown that peak current of I p eak=39 kA flows between the electrodes at P=11.5 mbar for the operation voltage of V=14 kV. Average total neutron yield is measured around 3.3x10 5 neutrons per shot using CR-39 plastic detectors located opposite the anode inside the PF chamber

Simulation of photons from plasmas for the applications to display devices

Science.gov (United States)

Lee, Hae June; Yoon, Hyun Jin; Lee, Jae Koo

2007-07-01

Numerical modeling of the photon transport of the ultraviolet (UV) and the visible lights are presented for plasma based display devices. The transport of UV lights which undergo resonance trapping by ground state atoms is solved by using the Holstein equation. After the UV lights are transformed to visible lights at the phosphor surfaces, the visible lights experience complicated traces inside the cell and finally are emitted toward the viewing window after having some power loss within the cell. A three-dimensional ray trace of the visible lights is calculated with a radiosity model. These simulations for the photons strengthen plasma discharge modeling for the application to display devices.

An investigation of the plasma behaviour in a Filippov type plasma focus device

Energy Technology Data Exchange (ETDEWEB)

Mahabadi, T D [Plasma Physics Research Center, I.A.U, PO Box 14665-678, Tehran (Iran, Islamic Republic of); Tafreshi, M A [School of Plasma Physics and Nuclear Fusion, Institute of Nuclear Science and Technology, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)

2007-09-15

Plasma behaviour in the 90 kJ Filippov type plasma focus (PF) device Dena, is studied both experimentally and theoretically. The latest experimental data obtained by the use of the Dena facility are presented. Then the experimental data are compared with the simulated data obtained through the ML model. This study shows that the ML model, to a good extent, is capable of predicting the plasma behaviour in the Filippov type PF. The experimental and the theoretical results show that the increment of the discharge voltage leads to an almost linear decrement of the pinch time. It is also shown that the increment of the pressure leads to a decrement of the current sheath expansion velocity. Finally, a semiempirical method for determination of the permitted values of the current efficiency factor and the mass shedding factor is presented.

Improvement of ITO properties in green-light-emitting devices by using N2:O2 plasma treatment

Science.gov (United States)

Jeon, Hyeonseong; Kang, Seongjong; Oh, Hwansool

2016-01-01

Plasma treatment reduces the roughness of the indium-tin-oxide (ITO) interface in organic light emitting diodes (OLEDs). Oxygen gas is typically used in the plasma treatment of conventional OLED devices. However, in this study, nitrogen and oxygen gases were used for surface treatment to improve the properties of ITO. To investigate the improvements resulting from the use of nitrogen and oxygen plasma treatment, fabricated green OLED devices. The device's structure was ITO (600 Å) / α-NPD (500 Å) / Alq3:NKX1595 (400 Å:20 Å,5%) / LiF / Al:Li (10 Å:1000 Å). The plasma treatment was performed in a capacitive coupled plasma (CCP) type plasma treatment chamber similar to that used in the traditional oxygen plasma treatment. The results of this study show that the combined nitrogen/oxygen plasma treatment increases the lifetime, current density, and brightness of the fabricated OLED while decreasing the operating voltage relative to those of OLEDs fabricated using oxygen plasma treatment.

Preliminary investigation on the use of low current pulsed power Z-pinch plasma devices for the study of early stage plasma instabilities

Science.gov (United States)

Kaselouris, E.; Dimitriou, V.; Fitilis, I.; Skoulakis, A.; Koundourakis, G.; Clark, E. L.; Chatzakis, J.; Bakarezos, Μ; Nikolos, I. K.; Papadogiannis, N. A.; Tatarakis, M.

2018-01-01

This article addresses key features for the implementation of low current pulsed power plasma devices for the study of matter dynamics from the solid to the plasma phase. The renewed interest in such low current plasma devices lies in the need to investigate methods for the mitigation of prompt seeding mechanisms for the generation of plasma instabilities. The low current when driven into thick wires (skin effect mode) allows for the simultaneous existence of all phases of matter from solid to plasma. Such studies are important for the concept of inertial confinement fusion where the mitigation of the instability seeding mechanisms arising from the very early moments within the target’s heating is of crucial importance. Similarly, in the magnetized liner inertial fusion concept it is an open question as to how much surface non-uniformity correlates with the magneto-Rayleigh-Taylor instability, which develops during the implosion. This study presents experimental and simulation results, which demonstrate that the use of low current pulsed power devices in conjunction with appropriate diagnostics can be important for studying seeding mechanisms for the imminent generation of plasma instabilities in future research.

In-liquid plasma devices and methods of use thereof

KAUST Repository

Cha, Min; Hamdan, Ahmad Bassam

2017-01-01

Devices and methods for generating a plasma in a liquid are provided. A low- dielectric material can be placed in contact with the liquid to form an interface a distance from an anode. A voltage can be applied across the anode and a cathode

High power gyrotrons: a close perspective

International Nuclear Information System (INIS)

Kartikeyan, M.V.

2012-01-01

, nonlinear spectroscopy, materials processing and plasma chemistry. In this talk, a close perspective of these high power millimeter wave sources (gyro-devices), an overview of their state-of-the-art developmental status, and applications will be presented keeping in view the needs and applications of such exquisite electron devices of much technological importance. (author)

Measurements of line-averaged electron density of pulsed plasmas using a He-Ne laser interferometer in a magnetized coaxial plasma gun device

Science.gov (United States)

Iwamoto, D.; Sakuma, I.; Kitagawa, Y.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2012-10-01

In next step of fusion devices such as ITER, lifetime of plasma-facing materials (PFMs) is strongly affected by transient heat and particle loads during type I edge localized modes (ELMs) and disruption. To clarify damage characteristics of the PFMs, transient heat and particle loads have been simulated by using a plasma gun device. We have performed simulation experiments by using a magnetized coaxial plasma gun (MCPG) device at University of Hyogo. The line-averaged electron density measured by a He-Ne interferometer is 2x10^21 m-3 in a drift tube. The plasma velocity measured by a time of flight technique and ion Doppler spectrometer was 70 km/s, corresponding to the ion energy of 100 eV for helium. Thus, the ion flux density is 1.4x10^26 m-2s-1. On the other hand, the MCPG is connected to a target chamber for material irradiation experiments. It is important to measure plasma parameters in front of target materials in the target chamber. In particular, a vapor cloud layer in front of the target material produced by the pulsed plasma irradiation has to be characterized in order to understand surface damage of PFMs under ELM-like plasma bombardment. In the conference, preliminary results of application of the He-Ne laser interferometer for the above experiment will be shown.

Method of controlling plasma discharge in a thermonuclear device

International Nuclear Information System (INIS)

Kawasaki, Kozo; Ishida, Takayuki; Takemaru, Koichi; Kawasaki, Takahide.

1982-01-01

Purpose: To prolong the plasma discharging period by previously increasing the temperature at the thick portion of a vacuum container prior to the plasma discharge to thereby decrease the temperature difference caused by the plasma discharge between the thick portion and the bellows. Method: Temperature values at the outer surface of the thick portion and the bellows of a vacuum container detected by temperature sensors are applied to the input processing section of a temperature control device, and baking control is carried out by way of the output processing section so that each of the portions of the vacuum container may be maintained at the temperature set by the temperature setting section based on the calculation performed in the control processing section. By previously increasing the temperature β at the thick portion higher by about 100 0 C than the temperature α for the bellows in the baking treatment prior to the plasma discharge, the plasma discharge period during which the temperature levels at both of the portions are reversed after the plasma discharge and the temperature difference arrives at a predetermined level i.g., of 100 0 C can significantly be prolonged as compared with the case where the plasma discharge is started at the same temperature for both of the portions. (Yoshino, Y.)

Development of the reactor lithium ampoule device for research of spectral-luminescent characteristics of nuclear-excited plasma

Energy Technology Data Exchange (ETDEWEB)

Batyrbekov, E.G. [National Nuclear Center of RK, Kurchatov (Kazakhstan); Gordienko, Yu. N., E-mail: gordienko@nnc.kz [National Nuclear Center of RK, Kurchatov (Kazakhstan); Ponkratov, Yu. V. [National Nuclear Center of RK, Kurchatov (Kazakhstan); Khasenov, M.U. [PI “National Laboratory Astana”, Astana (Kazakhstan); Tazhibayeva, I.L.; Barsukov, N.I.; Kulsartov, T.V.; Zaurbekova, Zh. A.; Tulubayev, Ye. Yu.; Skakov, M.K. [National Nuclear Center of RK, Kurchatov (Kazakhstan)

2017-04-15

Highlights: • The development procedure of the ampoule device for experiments with nuclear-excited plasma under neutron irradiation is described. • The methods of nuclear reactions’ energy conversion into the energy of optical radiation of nuclear-excited plasma are presented. • A scheme of reactor experiments, the experimental facility and experimental device to carry out the reactor experiments are considered. - Abstract: This paper describes the development procedure of the reactor ampoule device to perform the experiments on study of spectral luminescence characteristics of nuclear-excited plasma formed by products of {sup 6}Li(n,α){sup 3}H reaction under neutron irradiation at the IVG.1 M research reactor. The methods of nuclear reactions’ energy conversion into the energy of optical radiation of nuclear-excited plasma are presented. A scheme of reactor experiments, the experimental facility and experimental device to carry out the reactor experiments are considered in paper. The designed ampoule device is totally meets the requirements of irradiation experiments on the IVG.1M reactor.

Electro-mechanical probe positioning system for large volume plasma device

Science.gov (United States)

Sanyasi, A. K.; Sugandhi, R.; Srivastava, P. K.; Srivastav, Prabhakar; Awasthi, L. M.

2018-05-01

An automated electro-mechanical system for the positioning of plasma diagnostics has been designed and implemented in a Large Volume Plasma Device (LVPD). The system consists of 12 electro-mechanical assemblies, which are orchestrated using the Modbus communication protocol on 4-wire RS485 communications to meet the experimental requirements. Each assembly has a lead screw-based mechanical structure, Wilson feed-through-based vacuum interface, bipolar stepper motor, micro-controller-based stepper drive, and optical encoder for online positioning correction of probes. The novelty of the system lies in the orchestration of multiple drives on a single interface, fabrication and installation of the system for a large experimental device like the LVPD, in-house developed software, and adopted architectural practices. The paper discusses the design, description of hardware and software interfaces, and performance results in LVPD.

Quality, Stability, and Safety Data of Packed Red Cells and Plasma Processed by Gravity Separation Using a New Fully Integrated Hollow-Fibre Filter Device

Directory of Open Access Journals (Sweden)

T. Brune

2009-01-01

Full Text Available Background. We developed a completely closed system based on gravity separation without centrifugation steps for separation of whole blood. With this new system we compared quality and stability of the processed blood components (PRC and plasma with respect to classical preparation. Furthermore the cost-effectiveness of this hollow fibre system was evaluated. Study Design and Methods. Whole blood collections of 15 regular blood donors were used for component preparation using the U shaped hollow fibre filter device. Results were compared to 15 whole blood preparations using centrifugation. The following parameters were evaluated: total hemoglobin, leukocyte counts, the serum concentration of total protein, lactate dehydrogenase (LDH and potassium. Furthermore ATIII, vWF and F VIII were analyzed at different timepoints. Results. packed red cells: the data directly after separation and after 42 days of storage are in line with the guidelines of the council of Europe. Plasma. all plasma quality data are in line with the guidelines of the council of Europe for quality assurance of plasma, except for a low protein amount (factor 0.75. Conclusion. Separation of whole blood on a clinical scale in this new closed system is feasible, however the plasma protein content must be optimized.

External circuit integration with electromagnetic particle in cell modeling of plasma focus devices

International Nuclear Information System (INIS)

Seng, Y. S.; Lee, P.; Rawat, R. S.

2015-01-01

The pinch performance of a plasma focus (PF) device is sensitive to the physical conditions of the breakdown phase. It is therefore essential to model and study the initial phase in order to optimize device performance. An external circuit is self consistently coupled to the electromagnetic particle in cell code to model the breakdown and initial lift phase of the United Nations University/International Centre for Theoretical Physics (UNU-ICTP) plasma focus device. Gas breakdown during the breakdown phase is simulated successfully, following a drop in the applied voltage across the device and a concurrent substantial rise in the circuit current. As a result, the plasma becomes magnetized, with the growing value of the magnetic field over time leading to the gradual lift off of the well formed current sheath into the axial acceleration phase. This lifting off, with simultaneous outward sheath motion along the anode and vertical cathode, and the strong magnetic fields in the current sheath region, was demonstrated in this work, and hence validates our method of coupling the external circuit to PF devices. Our method produces voltage waveforms that are qualitatively similar to the observed experimental voltage profiles of the UNU-ICTP device. Values of the mean electron energy before and after voltage breakdown turned out to be different, with the values after breakdown being much lower. In both cases, the electron energy density function turned out to be non-Maxwellian

IEEE conference record -- Abstracts: 1996 IEEE international conference on plasma science

International Nuclear Information System (INIS)

Anon.

1996-01-01

This meeting covered the following topics: space plasmas; non-equilibrium plasma processing; computer simulation of vacuum power tubes; vacuum microelectronics; microwave systems; basic phenomena in partially ionized gases -- gaseous electronics, electrical discharges; ball lightning/spherical plasma configuration; plasma diagnostics; plasmas for lighting; dense plasma focus; intense ion and electron beams; plasma, ion, and electron sources; flat panel displays; fast z-pinches and x-ray lasers; environmental/energy issues in plasma science; thermal plasma processing; computational plasma physics; magnetic confinement fusion; microwave-plasma interactions; space plasma engineering; EM and ETH launchers; fast wave devices; intense beam microwaves; slow wave devices; space plasma measurements; basic phenomena in fully ionized plasma -- waves, instabilities, plasma theory, etc; plasma closing switches; fast opening switches; and laser-produced plasma. Separate abstracts were prepared for most papers in this conference

Divertor, thermonuclear device and method of neutralizing high temperature plasma

International Nuclear Information System (INIS)

Ikegami, Hideo.

1995-01-01

The thermonuclear device comprises a thermonuclear reactor for taking place fusion reactions to emit fusion plasmas, and a divertor made of a hydrogen occluding material, and the divertor is disposed at a position being in contact with the fusion plasmas after nuclear fusion reaction. The divertor is heated by fusion plasmas after nuclear fusion reaction, and hydrogen is released from the hydrogen occluding material as a constituent material. A gas blanket is formed by the released hydrogen to cool and neutralize the supplied high temperature nuclear fusion plasmas. This prevents the high temperature plasmas from hitting against the divertor, elimination of the divertor by melting and evaporation, and solve a problem of processing a divertor activated by neutrons. In addition, it is possible to utilize hydrogen isotopes of fuels effectively and remove unnecessary helium. Inflow of impurities from out of the system can also be prevented. (N.H.)

Design and development of a LIBS system on linear plasma device PSI-2 for in situ real-time diagnostics of plasma-facing materials

Directory of Open Access Journals (Sweden)

X. Jiang

2017-08-01

Full Text Available Laser induced breakdown spectroscopy (LIBS is a strong candidate for detecting and monitoring the H/D/T content on the surface of plasma facing components (PFCs due to its capability of fast direct in situ measurement in extreme environment (e.g., vacuum, magnetic field, long distance, complex geometry. To study the feasibilities and encounter the challenges of LIBS on plasma devices, a LIBS system has been set up on the linear plasma device PSI-2. A number of key parameters including laser energy, the influence of magnetic field and the persistence of laser induced plasma are studied. Real-time measurements of deuterium outgassing on tungsten samples exposed to deuterium plasma of 1025 D/m2 are performed in the first 40–130 min after plasma exposure. The experimental results are compared to the calculations in the literature.

Plasma Sheath Behavior in a Coaxial Discharge Device

International Nuclear Information System (INIS)

EL-Aragi, G.; Soliman, H.M.; Masoud, M.M.

2001-01-01

The behavior of the plasma sheath has been studied experimentally and theoretically for 3 kJ coaxial discharge device. The discharge takes place in argon gas with pressure of 0.8 mbar. The experiments are conducted with a 10 kV bank charging voltage, which corresponds to 110 kA peak discharge current with time period of 34 μs. The experimental investigations have been studied using a magnetic probes and a miniature Rogowsky coil. A snowplough model is used to drive an analytical solution of the plasma sheath behavior in axial direction. Measurements of radial distribution of plasma sheath current density J r at the muzzle, show that J r has the following relation, J r is proportional to r -1.1 . From the experimental results and theoretical calculations of axial distribution of azimuthal magnetic field induction and plasma sheath velocity, the inclination angle between the normal of the plasma sheath with the axial distance at any axial position is evaluated and it has approximately a constant value for most axial distances. Also, the axial motion of plasma sheath acceleration is estimated experimentally a max = 0.13 x 10 12 ' cm / s 2 at z = 11 cm and from theoretical calculations a max = 0.15 x 10 12 cm/ s 2 at max z = 1.6 cm. A comparison of the experimental results with the theoretical calculations, under the assumption of the snowplough model are not in agreement. (author)

Plasma characteristics of long-pulse discharges heated by neutral beam injection in the Large Helical Device

Science.gov (United States)

Takeiri, Y.; Nakamura, Y.; Noda, N.; Osakabe, M.; Kawahata, K.; Oka, Y.; Kaneko, O.; Tsumori, K.; Sato, M.; Mutoh, T.; Shimozuma, T.; Goto, M.; Ida, K.; Inagaki, S.; Kado, S.; Masuzaki, S.; Morita, S.; Nagayama, Y.; Narihara, K.; Peterson, B. J.; Sakakibara, S.; Sato, K.; Shoji, M.; Tanaka, K.; de Vries, P. C.; Sudo, S.; Ohyabu, N.; Motojima, O.

2000-02-01

Long-pulse neutral beam injection heating has been achieved in the large helical device (LHD). Two different confinement states are observed for different averaged densities in the long-pulse plasmas. A quasi-steady-state plasma was sustained for 21 s with an injection power of 0.6 MW, where the central plasma temperature was around 1 keV with a line-averaged electron density of 0.3 × 1019 m-3 . The discharge duration can be so extended as to keep the plasma properties in the short-pulse discharge. The energy confinement time is nearly the same as that of the short-pulse discharge, which is 1.3 times as long as the international stellarator scaling ISS95. At higher densities, a relaxation oscillation phenomenon, observed as if the plasma would breathe, lasted for 20 s with a period of 1-2 s. The phenomenon is characterized with profile expansion and contraction of the electron temperature. The density oscillation is out of phase with the temperature oscillation and is related to the density clamping phenomenon. The observed plasma properties are shown in detail for the `breathing' oscillation phenomenon. Possible mechanisms for the breathing oscillation are also discussed, with a view of the screening effect near the last closed magnetic surface and the power balance between the heating and the radiation powers. The long-pulse heating results indicate unique characteristics of the LHD where no special feedback stabilization is required due to absence of disruption and no need for current drive.

Characterization of high flux magnetized helium plasma in SCU-PSI linear device

Science.gov (United States)

Xiaochun, MA; Xiaogang, CAO; Lei, HAN; Zhiyan, ZHANG; Jianjun, WEI; Fujun, GOU

2018-02-01

A high-flux linear plasma device in Sichuan University plasma-surface interaction (SCU-PSI) based on a cascaded arc source has been established to simulate the interactions between helium and hydrogen plasma with the plasma-facing components in fusion reactors. In this paper, the helium plasma has been characterized by a double-pin Langmuir probe. The results show that the stable helium plasma beam with a diameter of 26 mm was constrained very well at a magnetic field strength of 0.3 T. The core density and ion flux of helium plasma have a strong dependence on the applied current, magnetic field strength and gas flow rate. It could reach an electron density of 1.2 × 1019 m-3 and helium ion flux of 3.2 × 1022 m-2 s-1, with a gas flow rate of 4 standard liter per minute, magnetic field strength of 0.2 T and input power of 11 kW. With the addition of -80 V applied to the target to increase the helium ion energy and the exposure time of 2 h, the flat top temperature reached about 530 °C. The different sizes of nanostructured fuzz on irradiated tungsten and molybdenum samples surfaces under the bombardment of helium ions were observed by scanning electron microscopy. These results measured in the SCU-PSI linear device provide a reference for International Thermonuclear Experimental Reactor related PSI research.

Surface modification study of zirconium on exposure to fusion grade plasma in an 11.5 kJ plasma focus device

International Nuclear Information System (INIS)

Srivastava, Rohit; Niranjan, Ram; Rout, R.K.; Kaushik, T.C.; Chakravarthy, Y.; Mishra, P.

2017-01-01

In continuation of our investigation on effect of fusion grade plasma produced in an existing MEPF-12 (11.5 kJ, 40 μF, 24 kV) plasma focus (PF) facility on different materials, likely to be used in future fusion reactors, we have reported here the study on Zirconium (Zr) metal. In the present work, the Zr sample in disc (2 mm thick, 10 mm diameter) form was exposed to twenty shots of plasma focus operated at 4 mbar deuterium gas filling pressure and 11.5 kJ bank energy. The samples were placed at a distance of 6 cm from the tip of the anode in the MEPF-12 PF device. The emissions from the device comprise of deuterium ions in wide energy range (a few keV to several hundreds of keV), high temperature plasma (in general a few keV) and neutrons of 2.45 MeV energy produced due to D(D, 3 He)n fusion reactions

Power accounting of plasma discharges in the linear device Proto-MPEX

Science.gov (United States)

Showers, M.; Piotrowicz, P. A.; Beers, C. J.; Biewer, T. M.; Caneses, J.; Canik, J.; Caughman, J. B. O.; Donovan, D. C.; Goulding, R. H.; Lumsdaine, A.; Kafle, N.; Owen, L. W.; Rapp, J.; Ray, H.

2018-06-01

Plasma material interaction (PMI) studies are crucial to the successful development of future fusion reactors. Prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a prototype design for the MPEX, a steady-state linear device being developed to study PMI. The primary purpose of Proto-MPEX is developing the plasma heating source concepts for MPEX. A power accounting study of Proto-MPEX works to identify machine operating parameters that could improve its performance, thereby increasing its PMI research capabilities, potentially impacting the MPEX design concept. To build a comprehensive power balance, an analysis of the helicon region has been performed implementing a diagnostic suite and software modeling to identify mechanisms and locations of heat loss from the main plasma. Of the 106.3 kW of input power, up to 90.5% of the power has been accounted for in the helicon region. When the analysis was extended to encompass the device to its end plates, 49.2% of the input power was accounted for and verified diagnostically. Areas requiring further diagnostic analysis are identified. The required improvements will be implemented in future work. The data acquisition and analysis processes will be streamlined to form a working model for future power balance studies of Proto-MPEX. ).

A Semi-Closed Device for Chromosome Spreading for Cytogenetic Analysis

DEFF Research Database (Denmark)

Kwasny, Dorota; Mednova, Olga; Vedarethinam, Indumathi

2014-01-01

a science. The chromosome spreading greatly depends on the environmental conditions such as humidity and temperature, which govern the evaporation of fixative, in which the cells are suspended. The spreading is normally performed manually in ambient conditions on glass slides, which are hydrophilic...... and a Topasr substrate rendered more hydrophilic by oxygen plasma treatment coupled with photografting. The device consists of a microfluidic chamber with perfusion holes that facilitate the evaporation of fixative and reliable formation of the spreads. The usability of the chromosome spreads formed...

Ohm close-quote s law for plasmas in reversed field pinch configuration

International Nuclear Information System (INIS)

Martines, E.; Vallone, F.

1997-01-01

An analytical relationship between current density and applied electric field in reversed field pinch (RFP) plasmas has been derived in the framework of the kinetic dynamo theory, that is assuming a radial field-aligned momentum transport caused by the magnetic field stochasticity. This Ohm close-quote s law yields current density profiles with a poloidal current density at the edge which can sustain the magnetic field configuration against resistive diffusion. The dependence of the loop voltage on plasma current and other plasma parameters for RFP experiments has been obtained. The results of the theoretical work have been compared with experimental data from the RFX experiment, and a good agreement has been found. copyright 1997 The American Physical Society

Plasma diagnostics in the CECI device through visible spectroscopy

International Nuclear Information System (INIS)

Ueda, M.; Kayama, M.E.; Aso, Y.

1991-11-01

In this paper we discuss the application of a visible spectrometer which was used to diagnose a plasma produced in an RFP device, called CECI. A Jobin Yvon, HR-640 S spectrometer with a photomultiplier detector was used to measure the Doppler broadening of lines emitted by the plasma, and allowed to measure the ion temperatures of the order of 2-3 eV. The electron temperature of 40-50 eV was determined by the method of He I line intensity ratio. The spectroscopically determined ion temperature is in better accordance with the 10 eV electron temperature obtained with an electrostatic probe. The line emissions of He II, H I, C II and O II were compared with signals from other diagnostics, and their correlations indicated the presence of MHD instabilities in the plasma. (author)

Deposition of aluminium nanoparticles using dense plasma focus device

International Nuclear Information System (INIS)

Devi, Naorem Bilasini; Srivastava, M P; Roy, Savita

2010-01-01

Plasma route to nanofabrication has drawn much attention recently. The dense plasma focus (DPF) device is used for depositing aluminium nanoparticles on n-type Si (111) wafer. The plasma chamber is filled with argon gas and evacuated at a pressure of 80 Pa. The substrate is placed at distances 4.0 cm, 5.0 cm and 6.0 cm from the top of the central anode. The aluminium is deposited on Si wafer at room temperature with two focused DPF shots. The deposits on the substrate are examined for their morphological properties using atomic force microscopy (AFM). The AFM images have shown the formation of aluminium nanoparticles. From the AFM images, it is found that the size of aluminium nanoparticles increases with increase in distance between the top of anode and the substrate for same number of DPF shots.

ERO modeling of Cr sputtering in the linear plasma device PSI-2

Science.gov (United States)

Eksaeva, A.; Borodin, D.; Kreter, A.; Nishijima, D.; Pospieszczyk, A.; Schlummer, T.; Ertmer, S.; Terra, A.; Unterberg, B.; Kirschner, A.; Romazanov, J.; Brezinsek, S.; Rasinski, M.; Henderson, S.; O'Mullane, M.; Summers, H.; Bluteau, M.; Marenkov, E.

2017-12-01

The prediction of the first wall deterioration and possible plasma contamination by impurities is a high priority task for ITER. 3D Monte-Carlo code ERO is a tool for modeling of eroded impurity transport and spectroscopy in plasma devices useful for experiment interpretation. Chromium (Cr) is a fusion-relevant reactor wall element (e.g. component of RAFM steels expected for use in DEMO). Linear plasma devices including PSI-2 are effective tools for investigations of plasma-surface interaction effects, allowing continuous plasma operation and good control over irradiation parameters. Experiments on Cr sputtering were conducted at PSI-2. In these experiments the Cr erosion was measured by three techniques: mass loss of the sample, quartz micro-balance of deposited impurities at a distance from it and optical emission spectroscopy. Experiments were modeled with the 3D Monte-Carlo code ERO, previously validated by application to similar experiments with tungsten (W). The simulations are demonstrated to reproduce the main experimental outcomes proving the quality of the sputtering data used. A significant focuses of the paper is the usage and validation of atomic data (resent metastable-resolved dataset from ADAS) for interpretation of Cr spectroscopy. Initial population of quasi-metastable state was fitted by matching the modeling with the experimental line intensity profiles.

Nonlinear stability of m=1 flute mode in a nonparaxial open plasma device

International Nuclear Information System (INIS)

Lanskij, I.M.; Stupakov, G.V.

1991-01-01

Plasma flute stability as to high shifts under strong effects of ion Larmor finite radius conditions is studied. System consisting of long axisymmetric paraxial mirror device with stabilizing cells at its edges is considered. Variation of plasma energy as to its shift as a whole is calculated. It is shown, that depending on stabilizer type the force bringing plasma back in equilibrium state with shift growth may both increase and decrease

[Evaluation of two closed-system drug transfer device in the antineoplastic drug elaboration process].

Science.gov (United States)

Gómez-Álvarez, Sandra; Porta-Oltra, Begoña; Hernandez-Griso, Marta; Pérez-Labaña, Francisca; Climente-Martí, Mónica

2016-01-01

to assess the impact of two closed-system drug transfer device on the local and environmental contamination and preparation times in the process of preparation of parenteral chemotherapy compared to the standard system. prospective observational study. Two different closed- systems providers, Care Fusion® and Icu Medical®, were compared to standard preparation. 15 nurses of Pharmacy Department prepared 5 preparations each one, one with the standard procedure and four using closed-systems. To evaluate the contamination, a fluorescein solution 0.5% was prepared. Two kind of contamination were evaluated, local (three points connection: closed-system connect vial, syringe and final infusion bags) and environmental (gloves and countertop). Percentage of contaminated preparations was obtained in each one. Time taken by each nurse in each preparation was recorded. 75 preparations were prepared. Local contamination was reduced 21% and 75% in closed-system Icu Medical® and Care Fusion® respectively. Care Fusion® closed system, local contamination was significantly lower than the standard system to the vial, syringe and final package, while Icu Medical® closed-systems only was significantly lower in the connection to the vial. Time of preparation was increased significantly with the use of closed-system between 23.4 and 30.5 seconds. both closed-systems drug transfer device have shown an improvement in contamination than the use of the standard system. However, preparation time has been significantly increased with the use of both systems. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Study on edge plasma physics and particle control in the Heliotron-E device

Energy Technology Data Exchange (ETDEWEB)

Mizuuchi, T; Obiki, T; Noda, N; Matsuura, H; Kondo, K; Akaishi, K; Motojima, O; Kaneko, H; Zushi, H; Takeiri, Y

1989-04-01

The edge plasma physics and the particle control under the intrinsic magnetic limiter configuration of a helical system have been studied with the Heliotron-E device, where currentless plasmas of T/sub e//le/1-2 keV, T/sub i//le/1 keV and anti n/sub e//le/2x10/sup 20//m/sup 3/ are produced by a combination of ECRH, NBI and/or ICRH. It is indicated that the separatrix region of the heliotron device is able to act as a divertor magnetic field. According to calculations of the magnetic field line in the edge region, the separatrix region has some different characteristics from the scrape-off layer in tokamak devices; the existence of a fine structure in the separatrix region and asymmetry of the region in toroidal and poloidal directions are observed. A localized pattern of the heat load on the first wall is experimentally observed. This agrees with the heat-load profile expected from the magnetic configuration and the distribution of the plasma in the edge region. A carbonization of the first wall is successfully applied to the Heliotron E device for reduction of metallic impurity contents. The heat load at the divertor trace decreased and that on the other part of the first wall increased in the high recycling conditions after the carbonization. (orig.).

Power source device for thermonuclear device

International Nuclear Information System (INIS)

Ozaki, Akira.

1992-01-01

The present invention provides a small sized and economical power source device for a thermonuclear device. That is, the device comprises a conversion device having a rated power determined by a power required during a plasma current excitation period and a conversion device having a rated power determined by a power required during a plasma current maintaining period, connected in series to each other. Then, for the former conversion device, power is supplied from an electric power generator and, for the latter, power is supplied from a power system. With such a constitution, during the plasma electric current maintaining period for substantially continuous operation, it is possible to conduct bypassing paired operation for the former conversion device while the electric power generator is put under no load. Further, since a short period rated power may be suffice for the former conversion device and the electric power generator having the great rated power required for the plasma electric current excitation period, they can be reduced in the size and made economical. On the other hand, since the power required for the plasma current maintaining period is relatively small, the capacity of the continuous rated conversion device may be small, and the power can be received from the power system. (I.S.)

Atmospheric pressure plasmas for surface modification of flexible and printed electronic devices: A review

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyong Nam; Lee, Seung Min; Mishra, Anurag [Department of Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Yeom, Geun Young, E-mail: gyyeom@skku.edu [Department of Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

2016-01-01

Recently, non-equilibrium atmospheric pressure plasma, especially those operated at low gas temperatures, have become a topic of great interest for the processing of flexible and printed electronic devices due to several benefits such as the reduction of process and reactor costs, the employment of easy-to-handle apparatuses and the easier integration into continuous production lines. In this review, several types of typical atmospheric pressure plasma sources have been addressed, and the processes including surface treatment, texturing and sintering for application to flexible and printed electronic devices have been discussed.

Nuclear fusion power supply device

International Nuclear Information System (INIS)

Nakagawa, Satoshi.

1975-01-01

Object: To use a hybrid power supply device, which comprises a thyristor power supply and a diode power supply, to decrease cost of a nuclear fusion power supply device. Structure: The device comprises a thyristor power supply connected through a closing unit and a diode power supply connected in parallel through a breaker, input of each power supply being applied with an output voltage of a flywheel AC generator. When a current transformer is excited, a disconnecting switch is turned on to close the diode power supply and a current of the current transformer is increased by an automatic voltage regulator to a set value within a predetermined period of time. Next, the current is cut off by a breaker, and when the breaker is in on position, the disconnecting switch is opened to turn on the closing unit. Thus, when a plasma electric current reaches a predetermined value, the breaker is turned on, and the current of the current transformer is controlled by the thyristor power supply. (Kamimura, M.)

Process automation system for integration and operation of Large Volume Plasma Device

International Nuclear Information System (INIS)

Sugandhi, R.; Srivastava, P.K.; Sanyasi, A.K.; Srivastav, Prabhakar; Awasthi, L.M.; Mattoo, S.K.

2016-01-01

Highlights: • Analysis and design of process automation system for Large Volume Plasma Device (LVPD). • Data flow modeling for process model development. • Modbus based data communication and interfacing. • Interface software development for subsystem control in LabVIEW. - Abstract: Large Volume Plasma Device (LVPD) has been successfully contributing towards understanding of the plasma turbulence driven by Electron Temperature Gradient (ETG), considered as a major contributor for the plasma loss in the fusion devices. Large size of the device imposes certain difficulties in the operation, such as access of the diagnostics, manual control of subsystems and large number of signals monitoring etc. To achieve integrated operation of the machine, automation is essential for the enhanced performance and operational efficiency. Recently, the machine is undergoing major upgradation for the new physics experiments. The new operation and control system consists of following: (1) PXIe based fast data acquisition system for the equipped diagnostics; (2) Modbus based Process Automation System (PAS) for the subsystem controls and (3) Data Utilization System (DUS) for efficient storage, processing and retrieval of the acquired data. In the ongoing development, data flow model of the machine’s operation has been developed. As a proof of concept, following two subsystems have been successfully integrated: (1) Filament Power Supply (FPS) for the heating of W- filaments based plasma source and (2) Probe Positioning System (PPS) for control of 12 number of linear probe drives for a travel length of 100 cm. The process model of the vacuum production system has been prepared and validated against acquired pressure data. In the next upgrade, all the subsystems of the machine will be integrated in a systematic manner. The automation backbone is based on 4-wire multi-drop serial interface (RS485) using Modbus communication protocol. Software is developed on LabVIEW platform using

Process automation system for integration and operation of Large Volume Plasma Device

Energy Technology Data Exchange (ETDEWEB)

Sugandhi, R., E-mail: ritesh@ipr.res.in; Srivastava, P.K.; Sanyasi, A.K.; Srivastav, Prabhakar; Awasthi, L.M.; Mattoo, S.K.

2016-11-15

Highlights: • Analysis and design of process automation system for Large Volume Plasma Device (LVPD). • Data flow modeling for process model development. • Modbus based data communication and interfacing. • Interface software development for subsystem control in LabVIEW. - Abstract: Large Volume Plasma Device (LVPD) has been successfully contributing towards understanding of the plasma turbulence driven by Electron Temperature Gradient (ETG), considered as a major contributor for the plasma loss in the fusion devices. Large size of the device imposes certain difficulties in the operation, such as access of the diagnostics, manual control of subsystems and large number of signals monitoring etc. To achieve integrated operation of the machine, automation is essential for the enhanced performance and operational efficiency. Recently, the machine is undergoing major upgradation for the new physics experiments. The new operation and control system consists of following: (1) PXIe based fast data acquisition system for the equipped diagnostics; (2) Modbus based Process Automation System (PAS) for the subsystem controls and (3) Data Utilization System (DUS) for efficient storage, processing and retrieval of the acquired data. In the ongoing development, data flow model of the machine’s operation has been developed. As a proof of concept, following two subsystems have been successfully integrated: (1) Filament Power Supply (FPS) for the heating of W- filaments based plasma source and (2) Probe Positioning System (PPS) for control of 12 number of linear probe drives for a travel length of 100 cm. The process model of the vacuum production system has been prepared and validated against acquired pressure data. In the next upgrade, all the subsystems of the machine will be integrated in a systematic manner. The automation backbone is based on 4-wire multi-drop serial interface (RS485) using Modbus communication protocol. Software is developed on LabVIEW platform using

Advances towards a portable pulsed source of neutrons and X-ray with energy of work close to 1 Joule

International Nuclear Information System (INIS)

Soto, Leopoldo; Pavez, C.; Moreno, Jose; Clausse, Alejandro; Barbaglia, Mario O.

2005-01-01

Plasma Focus devices are pulsed sources of X and neutron radiation from intense electrical discharges in deuterium. Classically these devices operate at energies between a few KJ to 1 MJ. In this work we present the design and feasibility studies of a Plasma Focus operating at energies close to 1 Joule. Experimental evidence of focalization is presented, and the optimum parameter relations at such low energies are discussed. The results indicate the device will be able to emit pulses about 1000 neutrons per J. (author) [es

System for deuterium-tritium mixture filling the working chamber of a dense plasma focus device

International Nuclear Information System (INIS)

Bondar', A.I.; Vyskubov, V.P.; Gerasimov, S.A.

1981-01-01

A gas-vacuum system designed for filling the gas-discharge chamber of a plasma focus device with equal-coaponent deuterium-tritium mixture is described. The system consists of a unit for gaseous mixture prepa ration and a unit for mixture absorption and device evacuation. The system provides the gaseous mixture purification of O 2 and N 2 impurities. Final tritium content in the gas-discharge chamber after tritium removal is not greater than 2x10 8 Bq/l. Tritium content in a sealed box in which the device is placed does not exceed 30 Bq/l that is less than limiting safe value. The conclusion is made that the described system design gives an opportunity to begin experimental studies at plasma focus devices with deuterium-tritium mixture [ru

Analysis of the interaction of deuterium plasmas with tungsten in the Fuego-Nuevo II device

Science.gov (United States)

Ramos, Gonzalo; Castillo, Fermín; Nieto, Martín; Martínez, Marco; Rangel, José; Herrera-Velázquez, Julio

2012-10-01

Tungsten is one of the main candidate materials for plasma-facing components in future fusion power plants. The Fuego-Nuevo II, a plasma focus device, which can produce dense magnetized helium and deuterium plasmas, has been adapted to address plasma-facing materials questions. In this paper we present results of tungsten targets exposed to deuterium plasmas in the Fuego Nuevo II device, using different experimental conditions. The plasma generated and accelerated in the coaxial gun is expected to have, before the pinch, energies of the order of hundreds eV and velocities of the order of 40,000 m s-1. At the pinch, the ions are reported to have energies of the order of 1.5 keV at most. The samples, analysed with a scanning electron microscope (SEM) in cross section show a damage profile to depths of the order of 580 nm, which are larger than those expected for ions with 1.5 keV, and may be evidence of ion acceleration. An analysis with the SRIM (Stopping Range of Ions in Matter) package calculations is shown.

Linear and nonlinear ion beam instabilities in a double plasma device

International Nuclear Information System (INIS)

Lee, S.G.; Diebold, D.; Hershkowitz, N.

1994-01-01

Ion beam instabilities in the double plasma device DOLI-1 were found to be quite sensitive to the difference between the source and target chamber plasma potentials when those potentials were within an electron temperature T e /e or so of each other. When the target chamber plasma potential of DOLI-1 was ≤ T e /e more positive than the source chamber plasma potential, a global ion beam-ion beam instability was observed. On the other hand, when the maximum target potential was between approximately 0.5 T e /e and 2.0 T e /e below the source potential, an ion-ion beam instability and a soliton associated with it were observed. This soliton is unique in that it is not launched but rather is self generated by the plasma and beam. When the target potential was less than source potential by more than two or so T e /e, the plasma was quite quiescent, which allowed small amplitude wave packet launched by Langmuir probe to be detected

Process and device for closing the apertures of a nuclear reactor core baffle formers

International Nuclear Information System (INIS)

Chevereau, G.

1990-01-01

The blades of at least two sets of blades along a shaft have bearing pads on the apertures of the formers with a length superior at the apertures radius. This device produces a transversal stagger of the shaft in two different directions in two zones of the shaft. It is possible to put in place and fix the closing device by an axial thrust [fr

Investigation of oxygen plasma treatment on the device performance of solution-processed a-IGZO thin film transistors

International Nuclear Information System (INIS)

Pu, Haifeng; Zhou, Qianfei; Yue, Lan; Zhang, Qun

2013-01-01

We reported the impact of oxygen plasma treatment on solution-processed amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs). Plasma-treated devices showed higher mobility, larger on/off current ratio, but a monotonically increased SS with plasma treatment time as well. The phenomenon was mainly due to two components in oxygen plasma, atomic oxygen and O 2 + , according to the photoluminescence (PL) measurement. Atomic oxygen reacted with oxygen vacancies in channel layer resulting in an improved mobility, and O 2 + tends to aggregated at the surface acting as trapping states simultaneously. Our study suggests that moderate oxygen plasma treatment can be adopted to improve the device performance, while O 2 + should be eliminated to obtain good interfacial states.

The pyrolytic-plasma method and the device for the utilization of hazardous waste containing organic compounds

Energy Technology Data Exchange (ETDEWEB)

Opalińska, Teresa [Tele and Radio Research Institute, Ratuszowa 11, 03-450 Warsaw (Poland); Wnęk, Bartłomiej, E-mail: bartlomiej.wnek@itr.org.pl [Tele and Radio Research Institute, Ratuszowa 11, 03-450 Warsaw (Poland); Witowski, Artur; Juszczuk, Rafał; Majdak, Małgorzata [Tele and Radio Research Institute, Ratuszowa 11, 03-450 Warsaw (Poland); Bartusek, Stanilav [VŠB—Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava − Poruba Czech Republic (Czech Republic)

2016-11-15

Highlights: • A first stage of the process of waste utilization consisted in pyrolysis of waste. • Then the pyrolytic gas was oxidized with a use of non-equilibrium plasma. • The device for the process implementation was built and characterized. • Correctness of the device operation was proven with a use of the decomposition of PE. • Usefulness of the method was proven in the process of utilization of EW. - Abstract: This paper is focused on the new method of waste processing. The waste, including hazardous waste, contain organic compounds. The method consists in two main processes: the pyrolysis of waste and the oxidation of the pyrolytic gas with a use of non-equilibrium plasma. The practical implementation of the method requires the design, construction and testing of the new device in large laboratory scale. The experiments were carried out for the two kinds of waste: polyethylene as a model waste and the electronic waste as a real waste. The process of polyethylene decomposition showed that the operation of the device is correct because 99.74% of carbon moles contained in the PE samples was detected in the gas after the process. Thus, the PE samples practically were pyrolyzed completely to hydrocarbons, which were completely oxidized in the plasma reactor. It turned out that the device is useful for decomposition of the electronic waste. The conditions in the plasma reactor during the oxidation process of the pyrolysis products did not promote the formation of PCDD/Fs despite the presence of the oxidizing conditions. An important parameter determining the efficiency of the oxidation of the pyrolysis products is gas temperature in the plasma reactor.

The application of selected radionuclides for monitoring of the D-D reactions produced by dense plasma-focus device.

Science.gov (United States)

Jednorog, S; Szydlowski, A; Bienkowska, B; Prokopowicz, R

The dense plasma focus (DPF) device-DPF-1000U which is operated at the Institute of Plasma Physics and Laser Microfusion is the largest that type plasma experiment in the world. The plasma that is formed in large plasma experiments is characterized by vast numbers of parameters. All of them need to be monitored. A neutron activation method occupies a high position among others plasma diagnostic methods. The above method is off-line, remote, and an integrated one. The plasma which has enough temperature to bring about nuclear fusion reactions is always a strong source of neutrons that leave the reactions area and take along energy and important information on plasma parameters and properties as well. Silver as activated material is used as an effective way of neutrons measurement, especially when they are emitted in the form of short pulses like as it happens from the plasma produced in Dense Plasma-Focus devices. Other elements such as beryllium and yttrium are newly introduced and currently tested at the Institute of Plasma Physics and Laser Microfusion to use them in suitable activation neutron detectors. Some specially designed massive indium samples have been recently adopted for angular neutrons distribution measurements (vertical and horizontal) and have been used in the recent plasma experiment conducted on the DPF-1000U device. This choice was substantiated by relatively long half-lives of the neutron induced isotopes and the threshold character of the 115 In(n,n') 115m In nuclear reaction.

Bursty fluctuation characteristics in SOL/divertor plasmas of large helical device

International Nuclear Information System (INIS)

Ohno, N.

2006-01-01

Full text: Fluctuation properties in the SOL plasmas were intensively studied to understand the crossfield plasma transport, which determines the SOL structure and heat/particle deposition onto the first wall. Recent studies in tokamaks showed that the SOL density fluctuation is highly intermittent. Convective cross-field transport associated with the intermittent events would have strong influence on recycling processes and impurity generation from the first wall. On the other hand, in helical devices, there are few systematic studies on the SOL fluctuation property focusing on the intermittent bursty fluctuations related to plasma blob transport. Recent theory predicts that the blobs propagate toward a low field side in tokamaks. On the other hand, in the Large Helical Device (LHD), the direction of the gradient in B is not uniform because the high-field and the low-field sides rotates poloidally along the torus in the helical system. Comparison between the intermittent bursty fluctuations in the edge plasma of tokamaks and helical devices makes it possible to understand the essential physics of the blob transport. Recently, fast camera observation showed the radial motion of filaments in the edge of the LHD, suggesting the convective cross-field transport. In this paper, bursty fluctuation properties in the edge of the LHD have been investigated by analyzing the ion saturation currents measured with a probe array embedded in an outboard divertor plate. Statistical analysis based on probability distribution function was employed to determine the intermittent evens in the density fluctuation. Large positive bursty events were often observed in the ion saturation current measured with a divertor probe near a divertor leg at which the magnetic line of force connected to the area of a low-field side with a short connection length. Condition averaging result of the positive bursty events indicates the intermittent feature with a rapid increase and a slow decay is

The plasma leptin concentration is closely associated with the body fat mass in nondiabetic uremic patients

DEFF Research Database (Denmark)

Clausen, P; Nielsen, P K; Olgaard, K

1999-01-01

filtration rate seemed to have a limited influence on the plasma leptin concentration in nondiabetic uremic subjects matched by body fat mass to controls. The plasma leptin concentration was closely associated with the body fat mass, and the leptin level might, therefore, be useful as an indicator of the fat......Plasma leptin is associated with the body mass index and, more precisely, with the body fat mass. Plasma leptin has been found to be elevated in uremic patients. This study aimed at investigating the plasma leptin concentration and associations between plasma leptin, body fat mass, and glomerular.......4 (3.1-59.5) ng/ml versus 5.4 (1.6-47.5) ng/ml (median and range in parentheses; p

Atmospheric pressure plasma jets: an overview of devices and new directions

International Nuclear Information System (INIS)

Winter, J; Brandenburg, R; Weltmann, K-D

2015-01-01

Atmospheric pressure plasma jets have a long history of more than 50 years. During this time their design and plasma generation mechanism has been developed and adapted to various fields of applications. This review aims at giving an overview of jet devices by starting with a brief history of their development. This is followed by an overview of commonly used terms and definitions as well as a survey of different classification schemes (e.g. geometry, excition frequency or specific energy input) described in literature. A selective update of new designs and novel research achievments on atmospheric pressure plasma jets published in 2012 or later shows the impressive variety and rapid development of the field. Finally, a brief outlook on the future trends and directions is given. (paper)

Closed-loop approach for situation awareness of medical devices and operating room infrastructure

Directory of Open Access Journals (Sweden)

Rockstroh Max

2015-09-01

Full Text Available In recent years, approaches for information and control integration in the digital operating room have emerged. A major step towards an intelligent operating room and a cooperative technical environment would be autonomous adaptation of medical devices and systems to the surgical workflow. The OR staff should be freed from information seeking and maintenance tasks. We propose a closed-loop concept integrating workflow monitoring, processing and (semi-automatic interaction to bridge the gap between OR integration of medical devices and workflow-related information management.

Ion implantation on nickel targets by means of repetitive plasma focus device

Energy Technology Data Exchange (ETDEWEB)

Vitulli, S.; Rapezzi, L. [ENEA Brasimone, Camugnano, Bologna (Italy); Apicella, M.L.; Samuelli, M. [ENEA Frascati, Frascati, Roma (Italy)

2004-07-01

Some test has been done in order to assess the possible use of a plasma focus as an implanter. The device utilized is the repetitive Plasma Focus operating in the ENEA Brasimone Center. The implanted sample is a sheet of Nickel with a surface of 17 cm{sup 2} inserted in a rigid sample at a variable distance from the top of the anode. After irradiation the sample is analyzed with Auger spectroscopy that provides the surface concentration of the various elements on the sample at different implantation depths. The result of the analysis shows that the Plasma Focus is an effective implantation source, even for metallurgical applications. (orig.)

Current sheath curvature correlation with the neon soft x-ray emission from plasma focus device

International Nuclear Information System (INIS)

Zhang, T; Lin, X; Chandra, K A; Tan, T L; Springham, S V; Patran, A; Lee, P; Lee, S; Rawat, R S

2005-01-01

The insulator sleeve length is one of the major parameters that can severely affect the neon soft x-ray yield from a plasma focus. The effect of the insulation sleeve length on various characteristic timings of plasma focus discharges and hence the soft x-ray emission characteristics has been investigated using a resistive divider. The pinhole images and laser shadowgraphy are used to explain the observed variation in the average soft x-ray yield (measured using a diode x-ray spectrometer) with variation of the insulator sleeve length. We have found that for a neon filled plasma focus device the change in insulator sleeve length changes the current sheath curvature angle and thus the length of the focused plasma column. The optimized current sheath curvature angle is found to be between 39 0 and 41 0 , at the specific axial position of 6.2-9.3 cm from the cathode support plate, for our 3.3 kJ plasma focus device. A strong dependence of the neon soft x-ray yield on the current sheath curvature angle has thus been reported

A device for heat-proofing the closing slab of a fast neutron nuclear reactor

International Nuclear Information System (INIS)

Lemercier, Guy.

1973-01-01

A device proofing the closing-slab comprising a metal-shoe against which is applied said device, the latter being constituted by a plurality of panels, each of which is formed by a padding of superimposed metal-cloths arranged in parallel relationship to the slab to be heat-proofed. Said device is characterized in that each panel is contained in a casing applied against the slab, constituted by two metal half-boxes of parallelepipedic shape embedded into each other. This can be applied to high-power reactors for protecting the slab against the aerosols of the coolant liquid-metal [fr

Potential formation in the plasma confinement region of a radio-frequency plugged linear device

International Nuclear Information System (INIS)

Fujita, Hideki; Kumazawa, Ryuhei; Howald, A.M.; Okamura, Shoichi; Sato, Teruyuki; Adati, Keizo; Garner, H.R.; Nishimura, Kiyohiko.

1987-08-01

Plasma potential formation in an open-ended plasma confinement system with RF plugging (the RFC-XX-M device) is investigated. The plasma potential in the central confinement region is measured with a heavy ion beam probe system and potentials at the RF plug section are measured with multi-grid energy analyzers. The measured plasma potential is compared with that deduced from the generalized Pastukhov formula. Results show that the plasma potential develops as an ambipolar potential to equate ion and electron end losses. During RF plugging, electrons are heated by Landau damping, while ions are not heated since adiabatic conditions apply during ion plugging in this experiment. (author)

Palm top plasma focus device as a portable pulsed neutron source

International Nuclear Information System (INIS)

Rout, R. K.; Niranjan, Ram; Srivastava, R.; Rawool, A. M.; Kaushik, T. C.; Gupta, Satish C.; Mishra, P.

2013-01-01

Development of a palm top plasma focus device generating (5.2 ± 0.8) × 10 4 neutrons/pulse into 4π steradians with a pulse width of 15 ± 3 ns is reported for the first time. The weight of the system is less than 1.5 kg. The system comprises a compact capacitor bank, a triggered open air spark gap switch, and a sealed type miniature plasma focus tube. The setup is around 14 cm in diameter and 12.5 cm in length. The energy driver for the unit is a capacitor bank of four cylindrical commercially available electrolytic capacitors. Each capacitor is of 2 μF capacity, 4.5 cm in diameter, and 9.8 cm in length. The cost of each capacitor is less than US$ 10. The internal diameter and the effective length of the plasma focus unit are 2.9 cm and 5 cm, respectively. A DC to DC converter power supply powered by two rechargeable batteries charges the capacitor bank to the desired voltage and also provides a trigger pulse of −15 kV to the spark gap. The maximum energy of operation of the device is 100 J (8 μF, 5 kV, 59 kA) with deuterium gas filling pressure of 3 mbar. The neutrons have also been produced at energy as low as 36 J (3 kV) of operation. The neutron diagnostics are carried out with a bank of 3 He detectors and with a plastic scintillator detector. The device is portable, reusable, and can be operated for multiple shots with a single gas filling.

Device for the simultaneous operation of the closing valve of a vessel and the closing valve of a transport container

International Nuclear Information System (INIS)

Tellier, Claude; Surriray, Michel.

1982-01-01

This device includes mechanisms for unlatching the closing valve of the vessel and securing it to the closing valve of the transport container and other mechanisms for vertically raising the assembly of valves, pivoting it and bringing it into a vertical position in a bulge provided in the bottom of the transport container. For example the first containment is a nuclear reactor vessel and the transport container is used for carrying an item from the vessel to an external area (for instance, a defective pump to the repair area) and for the return transport operation [fr

Computer simulation of a plasma focus device driven by a magnetic pulser

Energy Technology Data Exchange (ETDEWEB)

Georgescu, N; Zoita, V [Inst. of Physics and Technology of Radiation Devices, Bucharest (Romania); Larour, J [Ecole Polytechnique, Palaiseau (France). Lab. de Physique des Milieux Ionises

1997-12-31

A plasma focus device, driven by a magnetic pulse compression circuit, is simulated by using a PSPICE proffam. The elaborated program is much simpler than the other existing ones, which analyse the circuit by directly solving a system of integral-differential equations. The pre-pulse voltage and the high-voltage rise-times are obtained for a set of values of the bypass impedance (R or L). The optimum bypass impedance turns out to be an inductance. During the discharge period, the plasma load is considered as an LR impedance, each component being time dependent. A method is presented for giving us the possibility to introduce the time varying impedances in a PSPICE program. Finally, a set of simulation results (plasma current and voltage, plasma magnetic energy, plasma sheath mechanical energy, pinch voltage) is shown. The results are in good agreement with the classical experimental data. (author). 2 figs., 4 refs.

Electrostatic energy harvesting device with out-of-the-plane gap closing scheme

DEFF Research Database (Denmark)

Wang, Fei; Hansen, Ole

2014-01-01

In this paper, we report on an electrostatic energy harvester with an out-of-the-plane gap closing scheme. Using advanced MEMS technology, energy harvesting devices formed by a four wafer stack are batch fabricated and fully packaged at wafer scale. A spin coated CYTOP polymer is used both...... as an electret material and an adhesive layer for low temperature wafer bonding. The overall size of the device is about 1.1 cm × 1.3 cm. At an external load resistance of 13.4 MΩ, a power output of 0.15 μW is achieved when vibration at an acceleration amplitude of 1 g (∼9.8 m/s2) is applied at a low frequency...... of 96 Hz. The frequency response of the device is also measured and a broader bandwidth is observed at higher acceleration amplitude....

Electrostatic energy harvesting device with out-of-the-plane gap closing scheme

DEFF Research Database (Denmark)

Wang, Fei; Hansen, Ole

2013-01-01

In this paper, we report on an electrostatic energy harvester with an out-of-the-plane gap closing scheme. Using advanced MEMS technology, energy harvesting devices with a four wafer stack are batch fabricated and fully packaged at wafer scale. CYTOP polymer is used both as an electret material...... and an adhesive layer for low temperature wafer bonding. The overall size of the device is about 1.1×1.3 cm2. With an external load of 13.4 MΩ, a power output of 0.15 μW is achieved when vibration at an acceleration amplitude of 1 g (9.8 m/s2) is applied at a low frequency of 96 Hz. The frequency response...... of the device is also measured and a broader bandwidth is observed at higher acceleration amplitude. © 2013 IEEE....

Density and magnetic field measurements in the Tormac IV-c plasma

International Nuclear Information System (INIS)

Coonrod, J.W. Jr.

1978-01-01

Tormac is a concept for magnetically confining a high-β fusion plasma in a toroidal, stuffed line cusp. A Tormac plasma has two regions: an interior confined on the closed toroidal field lines of the stuffing field, and an exterior sheath on open, cusped field lines. The interior plasma gives the device a longer confinement time than a standard mirror, while the favorable curvature of the cusp fields allow the plasma to be stable at higher values of β (the ratio of the plasma pressure to magnetic pressure) than a totally closed configuration like Tokamak. This thesis describes the design, construction and operation of Tormac IV-c, and reports on the results, with emphasis on describing the behavior of the density compression and field penetration

Plasma sprayed TiC coatings for first wall protection in fusion devices

International Nuclear Information System (INIS)

Groot, P.; Laan, J.G. van der; Laas, L.; Mack, M.; Dvorak, M.

1989-01-01

For protection of plasma facing components in nuclear fusion devices thick titanium carbide coatings are being developed. Coatings have been produced by plasma spraying at atmospheric pressure (APS) and low pressure (LPPS) and analyzed with respect to microstructure and chemical composition. Thermo-mechanical evaluation has been performed by applying short pulse laser heat flux tests. The influence of coating thickness and porosity on the resistance to spalling by thermal shocks appears to be more important than aspects of chemical composition. (author)

Highly ionized copper contribution to the soft X-ray emission in a plasma focus device

Energy Technology Data Exchange (ETDEWEB)

Zoita, V; Patran, A [Inst. of Physics and Technology of Radiation Devices, Bucharest (Romania); Larour, J [Ecole Polytechnique, Palaiseau (France). Lab. de Physique des Milieux Ionises

1997-12-31

In order to discriminate between the contributions of the gas plasma and of the anode (solid or plasma) to the soft X-ray emission in a plasma focus device, a series of experiments was carried out using the following combinations of experimental conditions: various gases, different absorption filters and viewing different regions in front of the centre electrode. The experiments were performed on the IPF-2/20 plasma focus device using the following working gases: helium, neon and helium-argon mixtures. The diagnostics used: magnetic probe for current derivative, PIN diode for the minimum pinch radius detection, PIN diodes for the soft X-ray emission, scintillator-photomultiplier detector for the hard X-ray emission. From the analysis of the various diagnostics data recorded with very good time correlation, it followed that the soft K-ray signals had a strong contribution from optical transitions of the highly ionised Cu (Cu XX to XXII) emitting in the range 0.8-1.3 nm. (author). 7 figs., 9 refs.

System constitution of plasma high frequency heating device and element equipment

International Nuclear Information System (INIS)

Nagashima, Takashi

1988-01-01

On the high frequency heating device used for nuclear fusion experiment, the system constitution and the main items of development for the element equipment are described. As for the high frequency heating device, large technical progress was observed in the past 10 years as the second stage heating for tokamaks and one of the main means of current drive. At present, three frequency zones are regarded as promising for plasma high frequency heating in large nuclear fusion devices, and the experiment of 10 MW class is in progress at JT-60, JET and so on. There are electron cyclotron heating, lower hybrid resonance frequency heating and ion cyclotron range of frquency heating. The basic constitution of these heating devices includes a high frequency source, a transmission system, a connection system, and a common system for control, cooling, record and others. The ECH device using gyrotrons of several tens GHz, the LHRF heating device using large power klystrons up to several GHz and the ICRF heating device up to 200 MHz are briefly explained. The main element equipments composing the high frequency heating systems of several tens MW are discussed. (Kako, I.)

Artificial Pancreas Device Systems for the Closed-Loop Control of Type 1 Diabetes

Science.gov (United States)

Trevitt, Sara; Simpson, Sue; Wood, Annette

2015-01-01

Background: Closed-loop artificial pancreas device (APD) systems are externally worn medical devices that are being developed to enable people with type 1 diabetes to regulate their blood glucose levels in a more automated way. The innovative concept of this emerging technology is that hands-free, continuous, glycemic control can be achieved by using digital communication technology and advanced computer algorithms. Methods: A horizon scanning review of this field was conducted using online sources of intelligence to identify systems in development. The systems were classified into subtypes according to their level of automation, the hormonal and glycemic control approaches used, and their research setting. Results: Eighteen closed-loop APD systems were identified. All were being tested in clinical trials prior to potential commercialization. Six were being studied in the home setting, 5 in outpatient settings, and 7 in inpatient settings. It is estimated that 2 systems may become commercially available in the EU by the end of 2016, 1 during 2017, and 2 more in 2018. Conclusions: There are around 18 closed-loop APD systems progressing through early stages of clinical development. Only a few of these are currently in phase 3 trials and in settings that replicate real life. PMID:26589628

Measurements of ion temperature and flow of pulsed plasmas produced by a magnetized coaxial plasma gun device using an ion Doppler spectrometer

Science.gov (United States)

Kitagawa, Y.; Sakuma, I.; Iwamoto, D.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2012-10-01

It is important to know surface damage characteristics of plasma-facing component materials during transient heat and particle loads such as type I ELMs. A magnetized coaxial plasma gun (MCPG) device has been used as transient heat and particle source in ELM simulation experiments. Characteristics of pulsed plasmas produced by the MCPG device play an important role for the plasma material interaction. In this study, ion temperature and flow velocity of pulsed He plasmas were measured by an ion Doppler spectrometer (IDS). The IDS system consists of a light collection system including optical fibers, 1m-spectrometer and a 16 channel photomultiplier tube (PMT) detector. The IDS system measures the width and Doppler shift of HeII (468.58 nm) emission line with the time resolution of 1 μs. The Doppler broadened and shifted spectra were measured with 45 and 135 degree angles with respect to the plasmoid traveling direction. The observed emission line profile was represented by sum of two Gaussian components to determine the temperature and flow velocity. The minor component at around the wavelength of zero-velocity was produced by the stationary plasma. As the results, the ion velocity and temperature were 68 km/s and 19 eV, respectively. Thus, the He ion flow energy is 97 eV. The observed flow velocity agrees with that measured by a time of flight technique.

Plasma position control device

International Nuclear Information System (INIS)

Takase, Haruhiko.

1987-01-01

Purpose: To conduct position control stably to various plasmas and reduce the burden on the control coil power source. Constitution: Among the proportional, integration and differentiation controls, a proportional-differentiation control section and an integration control section are connected in parallel. Then, a signal switching circuit is disposed to the control signal input section for the proportional-differentiation control section such that either a present position of plasmas or deviation between the present plasma position and an aimed value can be selected as a control signal depending on the control procedures or the state of the plasmas. For instance, if a rapid response is required for the control, the deviation between the present plasma position and the aimed value is selected as the input signal to conduct proportional, integration and differentiation controls. While on the other hand, if it is intended to reduce the burden on the control coil power source, it is adapted such that the control signal inputted to the proportional-differentiation control section itself can select the present plasma position. (Yoshihara, H.)

Tritium breeding blanket device of D-T reactors

International Nuclear Information System (INIS)

Chevereau, G.

1984-01-01

This blanket device uses solid tritium breeding materials as those which include, in a known manner, near a neutron breeding plasma, a neutron multiplier medium and a tritium breeding medium, cooled by a cooling fluid circulation. This device is characterized by the fact that the association of the multiplier media and the tritium breeding media is realized by pellet alternated piling up of each of those both media, help in close contact on all their lateral surfaces [fr

Optimization of neon soft X-ray emission from 200 J plasma focus device for application in soft X-ray lithography

International Nuclear Information System (INIS)

Kalaiselvi, S.M. P.; Tan, T.L.; Talebitaher, A.; Lee, Paul; Rawat, R.S.

2014-01-01

The Fast Miniature Plasma Focus (FMPF) device is basically made up of coaxial electrodes with centrally placed anode and six cathode rods surrounding them concentrically. They are enclosed in a vacuum chamber, filled with low pressure operating gas. However, in our experiments, these cathode rods were removed to investigate the influence of them on neon soft X-ray (SXR) and hard X-ray (HXR) emission from the device. On removal of cathode rods, the cathode base plate serves as cathode and the plasma sheath is formed between the anode and the base plate of cathode. Neon was used as the operating gas for our experiments and the FMPF device used is of 235 J energy capacities. The experimental results showed that the FMPF device was able to focus better and the SXR emission efficiency was five times higher without cathode rods than with cathode rods. On the contrary, HXR emission did not vary with and without cathode rods. This observed phenomenon was further cross-checked through imaging of plasma dynamics, with and without cathode rods. FMPF device consists of 4 Pseudo Spark Gap (PSG) switches, which need to operate synchronously to deliver high voltage from capacitors to the anode. It was also seen that, the presence or absence of cathode rods also influence the synchronous operation of PSG switches. It also implies that this is one definite way to optimize the SXR emission from the FMPF device. This study reveals an important finding that, cathode rods play a vital role in the formation of plasma sheath with consequential influence on the radiation emission from plasma focus devices. Enhancement of the X-ray emission from this device is definitely a stepping stone in the realization of this device for industrial applications such as X-ray lithography for semiconductor industries. (author)

Pre-conceptual design activities for the materials plasma exposure experiment

International Nuclear Information System (INIS)

Lumsdaine, Arnold; Rapp, Juergen; Varma, Venugopal; Bjorholm, Thomas; Bradley, Craig; Caughman, John; Duckworth, Robert; Goulding, Richard; Graves, Van; Giuliano, Dominic; Lessard, Timothy; McGinnis, Dean; Meitner, Steven

2016-01-01

Highlights: • The development of long-pulse nuclear fusion devices requires testing plasma facing components at reactor relevant conditions. • The pre-conceptual design of a proposed linear plasma facility is presented. • Engineering considerations for multiple systems—plasma source and heating, magnet, vacuum, water cooling, and target, are presented. - Abstract: The development of next step fusion facilities such as DEMO or a Fusion Nuclear Science Facility (FNSF) requires first closing technology gaps in some critical areas. Understanding the material-plasma interface is necessary to enable the development of divertors for long-pulse plasma facilities. A pre-conceptual design for a proposed steady-state linear plasma device, the Materials Plasma Exposure Experiment (MPEX), is underway. A helicon plasma source along with ion cyclotron and electron Bernstein wave heating systems will produce ITER divertor relevant plasma conditions with steady-state parallel heat fluxes of up to 40 MW/m"2 with ion fluxes up to 10"2"4/m"2 s on target. Current plans are for the device to use superconducting magnets to produce 1–2 T fields. As a steady-state device, active cooling will be required for components that interact with the plasma (targets, limiters, etc.), as well as for other plasma facing components (transport regions, vacuum tanks, diagnostic ports). Design concepts for the vacuum system, the cooling system, and the plasma heating systems have been completed. The device will include the capability for handling samples that have been neutron irradiated in order to consider the multivariate effects of neutrons, plasma, and high heat-flux on the microstructure of divertor candidate materials. A vacuum cask, which can be disconnected from the high field environment in order to perform in-vacuo diagnosis of the surface evolution is also planned for the facility.

Pre-conceptual design activities for the materials plasma exposure experiment

Energy Technology Data Exchange (ETDEWEB)

Lumsdaine, Arnold, E-mail: lumsdainea@ornl.gov; Rapp, Juergen; Varma, Venugopal; Bjorholm, Thomas; Bradley, Craig; Caughman, John; Duckworth, Robert; Goulding, Richard; Graves, Van; Giuliano, Dominic; Lessard, Timothy; McGinnis, Dean; Meitner, Steven

2016-11-01

Highlights: • The development of long-pulse nuclear fusion devices requires testing plasma facing components at reactor relevant conditions. • The pre-conceptual design of a proposed linear plasma facility is presented. • Engineering considerations for multiple systems—plasma source and heating, magnet, vacuum, water cooling, and target, are presented. - Abstract: The development of next step fusion facilities such as DEMO or a Fusion Nuclear Science Facility (FNSF) requires first closing technology gaps in some critical areas. Understanding the material-plasma interface is necessary to enable the development of divertors for long-pulse plasma facilities. A pre-conceptual design for a proposed steady-state linear plasma device, the Materials Plasma Exposure Experiment (MPEX), is underway. A helicon plasma source along with ion cyclotron and electron Bernstein wave heating systems will produce ITER divertor relevant plasma conditions with steady-state parallel heat fluxes of up to 40 MW/m{sup 2} with ion fluxes up to 10{sup 24}/m{sup 2} s on target. Current plans are for the device to use superconducting magnets to produce 1–2 T fields. As a steady-state device, active cooling will be required for components that interact with the plasma (targets, limiters, etc.), as well as for other plasma facing components (transport regions, vacuum tanks, diagnostic ports). Design concepts for the vacuum system, the cooling system, and the plasma heating systems have been completed. The device will include the capability for handling samples that have been neutron irradiated in order to consider the multivariate effects of neutrons, plasma, and high heat-flux on the microstructure of divertor candidate materials. A vacuum cask, which can be disconnected from the high field environment in order to perform in-vacuo diagnosis of the surface evolution is also planned for the facility.

Dust in fusion devices-a multi-faceted problem connecting high- and low-temperature plasma physics

International Nuclear Information System (INIS)

Winter, J

2004-01-01

Small particles with sizes between a few nanometers and a few 10 μm (dust) are formed in fusion devices by plasma-surface interaction processes. Though it is not a major problem today, dust is considered a problem that could arise in future long pulse fusion devices. This is primarily due to its radioactivity and due to its very high chemical reactivity. Dust formation is particularly pronounced when carbonaceous wall materials are used. Dust particles can be transported in the tokamak over significant distances. Radioactivity leads to electrical charging of dust and to its interaction with plasmas and electric fields. This may cause interference with the discharge but may also result in options for particle removal. This paper discusses some of the multi-faceted problems using information both from fusion research and from low-temperature dusty plasma work

Magnetic pulse compression circuits for plasma devices

Energy Technology Data Exchange (ETDEWEB)

Georgescu, N; Zoita, V; Presura, R [Inst. of Physics and Technology of Radiation Devices, Bucharest (Romania)

1997-12-31

Two magnetic pulse compression circuits (MPCC), for two different plasma devices, are presented. The first is a 20 J/pulse, 3-stage circuit designed to trigger a low pressure discharge. The circuit has 16-18 kV working voltage, and 200 nF in each stage. The saturable inductors are realized with toroidal 25 {mu}m strip-wound cores, made of a Fe-Ni alloy, with 1.5 T saturation induction. The total magnetic volume is around 290 cm{sup 3}. By using a 25 kV/1 A thyratron as a primary switch, the time compression is from 3.5 {mu}s to 450 ns, in a short-circuit load. The second magnetic pulser is a 200 J/pulse circuit, designed to drive a high average power plasma focus soft X-ray source, for X-ray microlithography as the main application. The 3-stage pulser should supply a maximum load current of 100 kA with a rise-time of 250 - 300 ns. The maximum pulse voltage applied on the plasma discharge chamber is around 20 - 25 kV. The three saturable inductors in the circuit are made of toroidal strip-wound cores with METGLAS 2605 CO amorphous alloy as the magnetic material. The total, optimized mass of the magnetic material is 34 kg. The maximum repetition rate is limited at 100 Hz by the thyratron used in the first stage of the circuit, the driver supplying to the load about 20 kW average power. (author). 1 tab., 3 figs., 3 refs.

Fast mega pixels video imaging of a toroidal plasma in KT5D device

International Nuclear Information System (INIS)

Xu Min; Wang Zhijiang; Lu Ronghua; Sun Xiang; Wen Yizhi; Yu Changxuan; Wan Shude; Liu Wandong; Wang Jun; Xiao Delong; Yu Yi; Zhu Zhenghua; Hu Linyin

2005-01-01

A direct imaging system, viewing visible light emission from plasmas tangentially or perpendicularly, has been set up on the KT5D toroidal device to monitor the real two-dimensional profiles of purely ECR generated plasmas. This system has a typical spatial resolution of 0.2 mm (1280x1024 pixels) when imaging the whole cross section. Interesting features of ECR plasmas have been found. Different from what classical theories have expected, a resonance layer with two or three bright spots, rather than an even vertical band, has been observed. In addition, images also indicate an intermittent splitting and drifting character of the plasmas

Study on MHD instabilities in the CECI plasma device using Fourier probes

International Nuclear Information System (INIS)

Rosal, A.C.; Aso, Y.; Ueda, M.

1991-01-01

A magnetic diagnostics called Fourier analyser aiming to study MHD instabilities by Fourier series expansion of poloidal magnetic field for m ≤ 3 modes was developed and tested. The diagnostics will be used in the RFP (reversed field pinch) type toroidal plasma device. (M.C.K.)

Code improvements and applications of a two-dimensional edge plasma model for toroidal devices

International Nuclear Information System (INIS)

Baelmans, M.

1994-03-01

This thesis focuses mainly on plasma behaviour in boundary layers of magnetically confined plasmas. Increasing emphasis has been put on edge studies during the last decade, as it became evident that some aspects of Tokamak operations are largely controlled, or even dominated, by edge processes. Therefore, the motivation for this research is to improve understanding of plasma behaviour in general, and edge plasma behaviour in particular, firstly in present experiments, and also to predict edge plasma conditions in future nuclear fusion devices. In a first section some fundamental concepts and principles of controlled fusion are described. Two different types of plasma confinement concepts which have promising features with regard to the above mentioned goal are outlined in a next section, 1.2. In section 1.3 an introduction to plasma edge phenomena is given. In a last section, 1.4, the outline of the thesis is described. (orig.)

High density high performance plasma with internal diffusion barrier in Large Helical Device

International Nuclear Information System (INIS)

Sakamoto, R.; Kobayashi, M.; Miyazawa, J.

2008-10-01

A attractive high density plasma operational regime, namely an internal diffusion barrier (IDB), has been discovered in the intrinsic helical divertor configuration on the Large Helical Device (LHD). The IDB which enables core plasma to access a high density/high pressure regime has been developed. It is revealed that the IDB is reproducibly formed by pellet fueling in the magnetic configurations shifted outward in major radius. Attainable central plasma density exceeds 1x10 21 m -3 . Central pressure reaches 1.5 times atmospheric pressure and the central β value becomes fairly high even at high magnetic field, i.e. β(0)=5.5% at B t =2.57 T. (author)

Radially sheared azimuthal flows and turbulent transport in a cylindrical helicon plasma device

International Nuclear Information System (INIS)

Tynan, G R; Burin, M J; Holland, C; Antar, G; Diamond, P H

2004-01-01

A radially sheared azimuthal flow is observed in a cylindrical helicon plasma device. The shear flow is roughly azimuthally symmetric and contains both time-stationary and slowly varying components. The turbulent radial particle flux is found to peak near the density gradient maximum and vanishes at the shear layer location. The shape of the radial plasma potential profile associated with the azimuthal E x B flow is predicted accurately by theory. The existence of the mean shear flow in a plasma with finite flow damping from ion-neutral collisions and no external momentum input implies the existence of radial angular momentum transport from the turbulent Reynolds-stress

Plasma facing materials and components for future fusion devices - development, characterization and performance under fusion specific loading conditions

Energy Technology Data Exchange (ETDEWEB)

Linke, J. [Forschungszentrum Juelich (Germany). Inst. fuer Plasmaphysik

2006-04-15

The plasma exposed components in existing and future fusion devices are strongly affected by the plasma material interaction processes. These mechanisms have a strong influence on the plasma performance; in addition they have major impact on the lifetime of the plasma facing armour and the joining interface between the plasma facing material (PFM) and the heat sink. Besides physical and chemical sputtering processes, high heat quasi-stationary fluxes during normal and intense thermal transients are of serious concern for the engineers who develop reliable wall components. In addition, the material and component degradation due to intense fluxes of energetic neutrons is another critical issue in D-T-burning fusion devices which requires extensive RandD. This paper presents an overview on the materials development and joining, the testing of PFMs and components, and the analysis of the neutron irradiation induced degradation.

Plasma facing materials and components for future fusion devices - development, characterization and performance under fusion specific loading conditions

International Nuclear Information System (INIS)

Linke, J.

2006-01-01

The plasma exposed components in existing and future fusion devices are strongly affected by the plasma material interaction processes. These mechanisms have a strong influence on the plasma performance; in addition they have major impact on the lifetime of the plasma facing armour and the joining interface between the plasma facing material (PFM) and the heat sink. Besides physical and chemical sputtering processes, high heat quasi-stationary fluxes during normal and intense thermal transients are of serious concern for the engineers who develop reliable wall components. In addition, the material and component degradation due to intense fluxes of energetic neutrons is another critical issue in D-T-burning fusion devices which requires extensive RandD. This paper presents an overview on the materials development and joining, the testing of PFMs and components, and the analysis of the neutron irradiation induced degradation

Experimental study of the performance of a very small repetitive plasma focus device in different working conditions

Energy Technology Data Exchange (ETDEWEB)

Goudarzi, S., E-mail: sgoudarzi@aeoi.org.ir; Babaee, H.; Esmaeli, A.; Nasiri, A. [Atomic Energy Organization of Iran, Plasma and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute (Iran, Islamic Republic of)

2017-01-15

SORENA-1 is a very small repetitive Mather-type plasma focus device (20 J) that can operate at frequencies up to 1 Hz. This device has been designed and constructed in the Plasma and Nuclear Fusion Research School of the Nuclear Science and Technology Research Institute of Iran. In this article, the structure of SORENA-1 is described and results of experiments with Ar, Ne, and D{sub 2} working gases at several discharge voltages and initial pressures are presented and analyzed.

Hole injection enhancement in organic light emitting devices using plasma treated graphene oxide

Energy Technology Data Exchange (ETDEWEB)

Jesuraj, P. Justin; Parameshwari, R. [Centre for Nanoscience and Nanotechnology, School of Physics, Bharathidasan University, Tiruchirappalli, 620 024, Tamil Nadu (India); Kanthasamy, K.; Koch, J. [Institut für Festkörperphysik, ATMOS, Appelstr. 2, D-30167, Hannover (Germany); Pfnür, H. [Institut für Festkörperphysik, ATMOS, Appelstr. 2, D-30167, Hannover (Germany); Laboratorium für Nano- und Quantene$ngineering, Schneiderberg 30, D-30167, Hannover (Germany); Jeganathan, K., E-mail: kjeganathan@yahoo.com [Centre for Nanoscience and Nanotechnology, School of Physics, Bharathidasan University, Tiruchirappalli, 620 024, Tamil Nadu (India)

2017-03-01

Graphical abstract: Plasma treated Graphene oxide for hole injection enhancement in OLEDs. - Highlights: • Oxygen (O{sub 2}) and hydrogen (H{sub 2}) plasma exposed graphene oxide (GO) sheets have been demonstrated as hole buffer layers in OLEDs. • O{sub 2} plasma exposure induces assimilation of oxygen contents in GO lattice resulting in improved work function that reduced the hole injection barrier further. Whereas, H{sub 2} plasma contrastingly reduced the GO by excluding oxygen which ensuing lower work function. • X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy investigations reveal the capricious amount of oxygen in GO lattice and its corresponding work function variations. • GO and O{sub 2} plasma treated GO significantly improves the current efficiency of OLEDs more than one order with notable reduction in turn on voltage. - Abstract: The hole injection layer (HIL) with high work function (WF) is desirable to reduce the injection barrier between anode and hole transport layer in organic light emitting devices (OLED). Here, we report a novel approach to tune the WF of graphene oxide (GO) using oxygen and hydrogen plasma treatment and its hole injection properties in OLEDs. The mild exposure of oxygen plasma on GO (O{sub 2}-GO) significantly reduces the injection barrier by increasing the WF of anode (4.98 eV) through expansion of C−O bonds. In contrast, the hole injection barrier was drastically increased for hydrogen plasma treated GO (H{sub 2}-GO) layers as the WF is lowered by the contraction of C−O bond. By employing active O{sub 2}-GO as HIL in OLEDs found to exhibit superior current efficiency of 4.2 cd/A as compared to 3.3 cd/A for pristine GO. Further, the high injection efficiency of O{sub 2}-GO infused hole only device can be attributed to the improved energy level matching. Ultraviolet and X-ray photoelectron spectroscopy were used to correlate the WF of HIL infused anode towards the enhanced performance of

Characterization of light ion beams generated by a plasma focus device

International Nuclear Information System (INIS)

Koo, Bon Cheul

1999-02-01

Plasma focus device has been studied as neutron and X-ray sources generated from the high pressure fusion reaction during Z-pinch. Recently, the scope of the device is focused on efficient neutron generation, X-ray lithography, preliminary fusion experiment, and ion/electron beam generation devices. A Hexagonal Beam Generator with six parallel capacitors has been developed and generated ion beams from 30kJ(C=6 μ F, V= 100kV) maximum energy. To find the optimum condition of ion beam generation, the correlation among charging voltage(20∼30kV), operation pressure of chamber(0.1∼5 torr), and length of electrode has been studied. To measure ion beam, a Faraday Cup and 3 Rogowski coils were installed. Energy of ion beam was obtained by adopting time-of -flight method between Rogowski coils

Nitriding of Ti substrate using energetic ions from plasma focus device

International Nuclear Information System (INIS)

Henriquez, A; Bhuyan, H; Favre, M; Bora, B; Wyndham, E; Chuaqui, H; Mändl, S; Gerlach, J W; Manova, D

2012-01-01

Plasma Focus (PF) discharge is a pulsed plasma producing discharge that generates high temperature and high density plasma for a short duration. PF devices are known to emit intense ion beams pulses of characteristic energy in the keV to a few MeV range, in a time scale of tens of nanoseconds. We have previously investigated the ion flux and energy spectrum of ion beams emitted from a low energy PF, operating at 20 kV, with 1.8 kJ stored energy. It was observed that the ion beams have wide range of energy and intensity spectra with a clear angular anisotropy. Due to the wide range of ion energy and intensity spectra PF has become a subject of current interest for its applications in material sciences including surface modification and thin film deposition. The purpose of this study is the formation of titanium nitride (TiN) thin film and to investigate the structural properties of the TiN thin films in terms of PF angular positions. Substrates like Ti and Ti/Si were nitrided in a 1.8 kJ PF device at different angular positions with respect to the PF axis in order to correlate their surface properties with ion beam parameters. Preliminary characterizations of the ion implanted substrates have been conducted, using SEM, EDX and XRD. Our results indicate the formation of nanocrystalline TiN thin film only in certain angular positions. Angular dependency of the surface morphology was observed, which shows that the surface features strongly depends on ion beam energy and flux. With increasing angular positions, a reduction in the deposition rate and the sputter rate is observed. A pronounced nanostructured surface is only observed at the axis of the pinched plasma column, indicating the dominant role of sputtering and perhaps melting and fast re-crystallization of the surface in creating the nanostructures.

Performance of large electron energy filter in large volume plasma device

International Nuclear Information System (INIS)

Singh, S. K.; Srivastava, P. K.; Awasthi, L. M.; Mattoo, S. K.; Sanyasi, A. K.; Kaw, P. K.; Singh, R.

2014-01-01

This paper describes an in-house designed large Electron Energy Filter (EEF) utilized in the Large Volume Plasma Device (LVPD) [S. K. Mattoo, V. P. Anita, L. M. Awasthi, and G. Ravi, Rev. Sci. Instrum. 72, 3864 (2001)] to secure objectives of (a) removing the presence of remnant primary ionizing energetic electrons and the non-thermal electrons, (b) introducing a radial gradient in plasma electron temperature without greatly affecting the radial profile of plasma density, and (c) providing a control on the scale length of gradient in electron temperature. A set of 19 independent coils of EEF make a variable aspect ratio, rectangular solenoid producing a magnetic field (B x ) of 100 G along its axis and transverse to the ambient axial field (B z ∼ 6.2 G) of LVPD, when all its coils are used. Outside the EEF, magnetic field reduces rapidly to 1 G at a distance of 20 cm from the center of the solenoid on either side of target and source plasma. The EEF divides LVPD plasma into three distinct regions of source, EEF and target plasma. We report that the target plasma (n e ∼ 2 × 10 11  cm −3 and T e ∼ 2 eV) has no detectable energetic electrons and the radial gradients in its electron temperature can be established with scale length between 50 and 600 cm by controlling EEF magnetic field. Our observations reveal that the role of the EEF magnetic field is manifested by the energy dependence of transverse electron transport and enhanced transport caused by the plasma turbulence in the EEF plasma

Dose-current discharge correlation analysis in a Mather type Plasma Focus device for medical applications

Science.gov (United States)

Sumini, M.; Mostacci, D.; Tartari, A.; Mazza, A.; Cucchi, G.; Isolan, L.; Buontempo, F.; Zironi, I.; Castellani, G.

2017-11-01

In a Plasma Focus device the plasma collapses into the pinch where it reaches thermonuclear conditions for a few tens of nanoseconds, becoming a multi-radiation source. The nature of the radiation generated depends on the gas filling the chamber and the device working parameters. The self-collimated electron beam generated in the backward direction with respect to the plasma motion is one of the main radiation sources of interest also for medical applications. The electron beam may be guided against a high Z material target to produce an X-ray beam. This technique offers an ultra-high dose rate source of X-rays, able to deliver during the pinch a massive dose (up to 1 Gy per discharge for the PFMA-3 test device), as measured with EBT3 GafchromicⒸfilm tissue equivalent dosimeters. Given the stochastic behavior of the discharge process, a reliable on-line estimate of the dose-delivered is a very challenging task, in some way preventing a systematic application as a potentially interesting therapy device. This work presents an approach to linking the dose registered by the EBT3 GafchromicⒸfilms with the information contained in the signal recorded during the current discharge process. Processing the signal with the Wigner-Ville distribution, a spectrogram was obtained, displaying the information on intensity at various frequency scales, identifying the band of frequencies representative of the pinch events and define some patterns correlated with the dose.

Plasma parameter estimations for the Large Helical Device based on the gyro-reduced Bohm scaling

International Nuclear Information System (INIS)

Okamoto, Masao; Nakajima, Noriyoshi; Sugama, Hideo.

1991-10-01

A model of gyro-reduced Bohm scaling law is incorporated into a one-dimensional transport code to predict plasma parameters for the Large Helical Device (LHD). The transport code calculations reproduce well the LHD empirical scaling law and basic parameters and profiles of the LHD plasma are calculated. The amounts of toroidal currents (bootstrap current and beam-driven current) are also estimated. (author)

Compact and tunable focusing device for plasma wakefield acceleration

Science.gov (United States)

Pompili, R.; Anania, M. P.; Chiadroni, E.; Cianchi, A.; Ferrario, M.; Lollo, V.; Notargiacomo, A.; Picardi, L.; Ronsivalle, C.; Rosenzweig, J. B.; Shpakov, V.; Vannozzi, A.

2018-03-01

Plasma wakefield acceleration, either driven by ultra-short laser pulses or electron bunches, represents one of the most promising techniques able to overcome the limits of conventional RF technology and allows the development of compact accelerators. In the particle beam-driven scenario, ultra-short bunches with tiny spot sizes are required to enhance the accelerating gradient and preserve the emittance and energy spread of the accelerated bunch. To achieve such tight transverse beam sizes, a focusing system with short focal length is mandatory. Here we discuss the development of a compact and tunable system consisting of three small-bore permanent-magnet quadrupoles with 520 T/m field gradient. The device has been designed in view of the plasma acceleration experiments planned at the SPARC_LAB test-facility. Being the field gradient fixed, the focusing is adjusted by tuning the relative position of the three magnets with nanometer resolution. Details about its magnetic design, beam-dynamics simulations, and preliminary results are examined in the paper.

Proceedings of US/Japan workshop, Q219 on high heat flux components and plasma surface interactions for next fusion devices

Energy Technology Data Exchange (ETDEWEB)

Ulrickson, M.A.; Stevens, P.L.; Hino, T.; Hirohata, Y. [eds.

1996-12-01

This report contains the viewgraphs from the proceedings of US/Japan Workshop on High Heat Flux Components and Plasma Surface Interactions for Next Fusion Devices. Some of the general topics covered by this report are: PFC/PSI in tokamak and helical devices; development of high heat flux components; PSIS and plasma facing materials;tritium; and material damage.

Proceedings of US/Japan workshop, Q219 on high heat flux components and plasma surface interactions for next fusion devices

International Nuclear Information System (INIS)

Ulrickson, M.A.; Stevens, P.L.; Hino, T.; Hirohata, Y.

1996-12-01

This report contains the viewgraphs from the proceedings of US/Japan Workshop on High Heat Flux Components and Plasma Surface Interactions for Next Fusion Devices. Some of the general topics covered by this report are: PFC/PSI in tokamak and helical devices; development of high heat flux components; PSIS and plasma facing materials;tritium; and material damage

A physical model of Mirnov oscillations and plasma disruptions

International Nuclear Information System (INIS)

Cross, R.C.

1983-07-01

A physical model is proposed which accounts for the general behaviour of Mirnov oscillations and plasma disruptions in tokamak devices. The model also accounts for the stability of those devices which operate with edge safety factors less than 1.5. The model is based on the propagation of localized torsional Alfven and ion acoustic wavepackets. These packets remain phase coherent for considerable distances and are guided along helical field lines in toroidal plasmas, leading to the formation of standing waves on those field lines which close on themselves after one or more toroidal revolutions. Standing waves are driven resonantly on the rational surfaces by fluctuations in the poloidal field, causing localized heating and hence filamentation of the plasma current. This model indicates that Mirnov oscillations are produced by standing acoustic waves, while plasma disruptions occur as a result of the formation of MHD unstable current filaments

Current scaling of plasma focus devices

International Nuclear Information System (INIS)

Schiuma, C.; Herold, H.; Kaeppeler, H.J.; Shakhatre, M.; Auluck, S.K.H.

1990-03-01

In continuation of the work by G. Decker et al. on current and neutron yield scaling of plasma focus devices an analytical solution for the circuit equation (with resistance R = 0) in the compression phase was derived. Together with the solution for the rundown phase from G. Decker et al, which was extended for finite resistance (R ≠ 0), there follows an analytical scaling theory for maximum and pinch currents. At the same time there exists the possibility to discuss the influence of finite resistance on current variation and scaling parameters. The model solutions were checked out by numerical integrations of the current equation. While at the beginning of the rundown phase the ohmic resistance cannot be neglected (the magnitude R/L plays an important role), its influence at the end of the rundown phase and in the compression phase is negligible. The theoretically determined values are compared with the results of numerous probe measurements. (orig.)

Research program for plasma confinement and heating in ELMO bumpy torus devices

International Nuclear Information System (INIS)

Dandl, R.A.; Dory, R.A.; Eason, H.O.

1975-06-01

A sequence of experimental devices and related research activities which leads progressively toward an attractive full-scale reactor is described. The implementation of the steps in this sequence hinges on the development of microwave power sources, with high specific power levels, at millimeter wavelengths. Two proposed steps in this sequence are described. The first step proposed here, denoted EBT-S, requires increasing the EBT magnetic field to permit microwave heating at 18 and 28 GHz, as compared to the present 10.6 and 18-GHz configuration. A three-fold increase in plasma density, some increase in the temperatures, and an opportunity to test the validity of the transport models presently used to predict the plasma parameters are anticipated. This step will provide important operating experience with the 28-GHz power supplies, which are prototype tubes for millimeter sources at 120 GHz In the second step a new superconducting bumpy torus, EBT-II, would be fabricated to permit microwave heating at 90 and 120 GHz. This device would be designed to produce plasma densities and temperatures comparable to those of present-day tokamaks. This report reviews the experimental and theoretical research on EBT that has been carried out to date or formulated for the near future, and provides a status report as well as a research program plan. (U.S.)

A novel method of TVTS in the TS-3 device and the proposal of its application to a large device

International Nuclear Information System (INIS)

Tokimatsu, K.; Hayashi, N.; Ueda, Y.; Ono, Y.; Katsurai, M.

1997-01-01

A novel method of television Thomson scattering (TVTS) has been developed in the TS-3 device. In this system, a framing camera is located between a spectroscope and a close coupled device camera. This framing camera can take two successive frames from the exit of the spectroscope. The time interval is of 500 ns between those two frames. Because of the shortness of this time interval, the background light is negligible; moreover TVTS is applicable to the TS-3 device whose plasma lifetime is about 150 μs. This method indicates the possibility of not only high spatial resolution but also time repetition in a simple system. (orig.)

Closed Loop Control Compact Exercise Device for Use on MPCV

Science.gov (United States)

Sheehan, Chris; Funk, Justin; Funk, Nathan; Kutnick, Gilead; Humphreys, Brad; Bruinsma, Douwe; Perusek, Gail

2016-01-01

Long duration space travel to Mars or to an asteroid will expose astronauts to extended periods of reduced gravity. To combat spaceflight physiological deconditioning, astronauts will use resistive and aerobic exercise regimens for the duration of the space flight to minimize the loss of bone density, muscle mass and aerobic capacity that occurs during exposure to a reduced gravity environment. Unlike the International Space Station (ISS), the mass and volume available for an exercise device in the next generation of spacecraft is limited. Therefore, compact exercise device prototypes are being developed for human in the loop evaluations. The NASA Human Research Program (HRP) is managing Advanced Exercise Concepts (AEC) requirements development and candidate technology maturation for all exploration mission profiles from Multi-Purpose Crew Vehicle (MPCV) exploration missions (e.g., EM-2, up to 21 day) to Mars Transit (up to 1000 day) missions. Numerous technologies have been considered and evaluated against HRP-approved functional requirements and include flywheel, pneumatic and closed-loop microprocessor-controlled motor driven power plants. Motor driven technologies offer excellent torque density and load accuracy characteristics as well as the ability to create custom mechanical impedance (the dynamic relationship between force and velocity) and custom load versus position exercise algorithms. Further, closed-loop motor-driven technologies offer the ability to monitor exercise dose parameters and adapt to the needs of the crewmember for real time optimization of exercise prescriptions. A simple proportional-integral-derivative (PID) controller is demonstrated in a prototype motor driven exercise device with comparison to resistive static and dynamic load set points and aerobic work rate targets. The resistive load term in the algorithm includes a constant force component (Fcmg) as well as inertial component (Fima) and a discussion of system tuning is presented

Interaction of dense nitrogen plasma with SS304 surface using APF plasma focus device

Science.gov (United States)

Afrashteh, M.; Habibi, M.; Heydari, E.

2012-04-01

The nitridation of SS304 surfaces is obtained by irradiating nitrogen ions from Amirkabir plasma focus device, which use multiple focus deposition shots at optimum distance 10 cm from the anode. The Vickers Micro-Hardness values are improved more than twice for the nitrided samples comparing to the nonnitrided ones. The X-ray diffraction (XRD) analysis is carried out in order to explore the phase changes in the near surface structure of the metals. The results of Scanning Electron Microscopy (SEM) indicate changes in surface morphology which are the emergence of smooth and uniform film on the surface of the nitrided metals.

Interchangeable opening and closing clapper device notably for ventilation ducts utilizing an aggressive or polluting fluid

International Nuclear Information System (INIS)

1980-01-01

This opening and closing device is of the type which employs a casing inside the duct along the fluid path. It is provided with an opening through which the fluid flows and a joint with a closing clapper controlled from the outside enabling the fluid flow to be regulated. It is characterized by the fact that the casing is provided with a lateral opening with respect to the fluid flow direction, the size of this opening being sufficiently large to allow the assembly with its closing clapper to be introduced and withdrawn [fr

The measurement of potential distribution of plasma in MM-4 fusion device

International Nuclear Information System (INIS)

Tian Zhongyu; Ming Linzhou; Feng Xiaozhen; Feng Chuntang; Yi Youjun; Wang Jihai; Liu Yihua

1988-11-01

Some experimental results of the potential distribution in MM-4 fusion device are presented by measuring the floating potential of probe. The results showed that the distribution of axial potential is asymmetrical, but the radial potential is symmetrical. There are double ion potential wells in the plasma. The depth of the deepest potential well become deeper is the strength of the magnetic field and injection current are increasing. The location of the deepest well is moved towards the device center along with the increasing of injection energy. This is different from others results. The mechanism of causing this distribution in also discussed

Development of the closed-loop Joule-Thomson cryoablation device for long area cooling

Energy Technology Data Exchange (ETDEWEB)

Lee, Cheon Kyu; Park, Inn Yong; Yoo, Dong Gyu; Jeong, Sang Kwon [Cryogenic Engineering Laboratory, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Park Sang Woo [Konkuk University Hospital, School of Medicine, Konkuk University, Seoul (Korea, Republic of)

2013-09-15

Cryoablation device is a surgical instrument to produce the cooling effect to destroy detrimental biological tissue by utilizing low temperature around 110 K. Usually, this device has the concentrated cooling region, so that it is suitable for concentrated and thick target. Accordingly, it is hard to apply this device for the target which is distributed and thin target. In this study, the design procedure of a closed-loop cryoablation device with multiple J-T expansion part is developed for the treatment of incompetent of great saphenous vein. The developed cyoablation device is designed with the analysis of 1-dimensional (1-D) bio-heat equation. The energy balance is considered to determine the minimum mass flow rate of refrigerant for consecutive flow boiling to develop the uniform cooling temperature. Azeotropic mixed refrigerant R410A and zeotropic mixed refrigerant (MR) of R22 (CHClF{sub 2}) and R23 (CHF{sub 3}) are utilized as operating fluids of the developed cryoablation device to form the sufficient temperature and to verify the quality of the inside of cryoablation probe. The experimental results of R410A and the zeotropic MR show the temperature non-uniformity over the range are 244.8K±2.7K and 239.8K±4.7K respectively. The experimental results demonstrate that the probe experiences the consecutive flow boiling over the target range of 200 mm.

Plasma centrifuges

International Nuclear Information System (INIS)

Karchevskij, A.I.; Potanin, E.P.

2000-01-01

The review of the most important studies on the isotope separation processes in the rotating plasma is presented. The device is described and the characteristics of operation of the pulse plasma centrifuges with weakly and strongly ionized plasma as well as the stationary plasma centrifuges with the medium weak ionization and devices, applying the stationary vacuum arc with the high ionization rate and the stationary beam-plasma discharge with complete ionization, are presented. The possible mechanisms of the isotope separation in plasma centrifuges are considered. The specific energy consumption for isotope separation in these devices is discussed [ru

State of art data acquisition system for large volume plasma device

International Nuclear Information System (INIS)

Sugandhi, Ritesh; Srivastava, Pankaj; Sanyasi, Amulya Kumar; Srivastav, Prabhakar; Awasthi, Lalit Mohan; Mattoo, Shiban Krishna; Parmar, Vijay; Makadia, Keyur; Patel, Ishan; Shah, Sandeep

2015-01-01

The Large volume plasma device (LVPD) is a cylindrical device (ϕ = 2m, L = 3m) dedicated for carrying out investigations on plasma physics problems ranging from excitation of whistler structures to plasma turbulence especially, exploring the linear and nonlinear aspects of electron temperature gradient(ETG) driven turbulence, plasma transport over the entire cross section of LVPD. The machine operates in a pulsed mode with repetition cycle of 1 Hz and acquisition pulse length of duration of 15 ms, presently, LVPD has VXI data acquisition system but this is now in phasing out mode because of non-functioning of its various amplifier stages, expandability and unavailability of service support. The VXI system has limited capabilities to meet new experimental requirements in terms of numbers of channel (16), bit resolutions (8 bit), record length (30K points) and calibration support. Recently, integration of new acquisition system for simultaneous sampling of 40 channels of data, collected over multiple time scales with high speed is successfully demonstrated, by configuring latest available hardware and in-house developed software solutions. The operational feasibility provided by LabVIEW platform is not only for operating DAQ system but also for providing controls to various subsystems associated with the device. The new system is based on PXI express instrumentation bus and supersedes the existing VXI based data acquisition system in terms of instrumentation capabilities. This system has capability to measure 32 signals at 60 MHz sampling frequency and 8 signals with 1.25 GHz with 10 bit and 12 bit resolution capability for amplitude measurements. The PXI based system successfully addresses and demonstrate the issues concerning high channel count, high speed data streaming and multiple I/O modules synchronization. The system consists of chassis (NI 1085), 4 high sampling digitizers (NI 5105), 2 very high sampling digitizers (NI 5162), data streaming RAID drive (NI

A new multi-line cusp magnetic field plasma device (MPD) with variable magnetic field

Science.gov (United States)

Patel, A. D.; Sharma, M.; Ramasubramanian, N.; Ganesh, R.; Chattopadhyay, P. K.

2018-04-01

A new multi-line cusp magnetic field plasma device consisting of electromagnets with core material has been constructed with a capability to experimentally control the relative volume fractions of magnetized to unmagnetized plasma volume as well as accurate control on the gradient length scales of mean density and temperature profiles. Argon plasma has been produced using a hot tungsten cathode over a wide range of pressures 5 × 10-5 -1 × 10-3 mbar, achieving plasma densities ranging from 109 to 1011 cm-3 and the electron temperature in the range 1-8 eV. The radial profiles of plasma parameters measured along the non-cusp region (in between two consecutive magnets) show a finite region with uniform and quiescent plasma, where the magnetic field is very low such that the ions are unmagnetized. Beyond that region, both plasma species are magnetized and the profiles show gradients both in temperature and density. The electrostatic fluctuation measured using a Langmuir probe radially along the non-cusp region shows less than 1% (δIisat/Iisat physics parameter space relevant to both laboratory multi-scale plasmas and astrophysical plasmas.

Study of the Plasma Evolution in the PF-1000 Device by Means of Optical Diagnostics

International Nuclear Information System (INIS)

Kasperczuk, A.; Kumar, R.; Miklaszewski, R.; Paduch, M.; Pisarczyk, T.; Scholz, M.; Tomaszewski, K.

2002-01-01

Investigation of a plasma evolution was carried out in a PF-1000 device with the following parameters: diameter of the inner electrode -24.4 cm, diameter of the outer one -36.8 cm, charging voltage in the range of 30-40 kV and deuterium pressure in the range of 1-5 1 To study the evolution of the plasma, an optical frame camera and YAGlaser shadowgraphy, both with exposure times of about 1 ns, were employed. Among the cases analyzed of plasma focus discharges, two types of plasma sheath disturbance can be distinguished: type I - classical MHD m = 0 instability (a wave with four maxima in the main), type 11 - singular great scale disturbance. On the basis of the plasma images, the dynamics of the plasma sheath, characteristic periods of the plasma evolution and plasma dimensions were determined. In order to reconstruct the spatial distribution of the electron density a special method was prepared

High-Z plasma facing components in fusion devices: boundary conditions and operational experiences

Science.gov (United States)

Neu, R.

2006-04-01

In present day fusion devices optimization of the performance and experimental freedom motivates the use of low-Z plasma facing materials (PFMs). However, in a future fusion reactor, for economic reasons, a sufficient lifetime of the first wall components is essential. Additionally, tritium retention has to be small to meet safety requirements. Tungsten appears to be the most realistic material choice for reactor plasma facing components (PFCs) because it exhibits the lowest erosion. But besides this there are a lot of criteria which have to be fulfilled simultaneously in a reactor. Results from present day devices and from laboratory experiments confirm the advantages of high-Z PFMs but also point to operational restrictions, when using them as PFCs. These are associated with the central impurity concentration, which is determined by the sputtering yield, the penetration of the impurities and their transport within the confined plasma. The restrictions could exclude successful operation of a reactor, but concomitantly there exist remedies to ameliorate their impact. Obviously some price has to be paid in terms of reduced performance but lacking of materials or concepts which could substitute high-Z PFCs, emphasis has to be put on the development and optimization of reactor-relevant scenarios which incorporate the experiences and measures.

High-Z plasma facing components in fusion devices: boundary conditions and operational experiences

International Nuclear Information System (INIS)

Neu, R.

2006-01-01

In present day fusion devices optimization of the performance and experimental freedom motivates the use of low-Z plasma facing materials (PFMs). However, in a future fusion reactor, for economic reasons, a sufficient lifetime of the first wall components is essential. Additionally, tritium retention has to be small to meet safety requirements. Tungsten appears to be the most realistic material choice for reactor plasma facing components (PFCs) because it exhibits the lowest erosion. But besides this there are a lot of criteria which have to be fulfilled simultaneously in a reactor. Results from present day devices and from laboratory experiments confirm the advantages of high-Z PFMs but also point to operational restrictions, when using them as PFCs. These are associated with the central impurity concentration, which is determined by the sputtering yield, the penetration of the impurities and their transport within the confined plasma. The restrictions could exclude successful operation of a reactor, but concomitantly there exist remedies to ameliorate their impact. Obviously some price has to be paid in terms of reduced performance but lacking of materials or concepts which could substitute high-Z PFCs, emphasis has to be put on the development and optimization of reactor-relevant scenarios which incorporate the experiences and measures

MATURING ECRF TECHNOLOGY FOR PLASMA CONTROL

International Nuclear Information System (INIS)

CALLIS, R.W.; CARY, W.P.; CHU, S.; LOANE, J.L.; ELLIS, R.A.; FELCH, K.; GORELOV, Y.A.; GRUNLOH, H.J.; HOSEA, J.; KAJIWARA, K.; LOHR, J.; LUCE, T.C.; PEAVY, J.J.; PINSKER, R.I.; PONCE, D.; PRATER, R.; SHAPIRO, M.; TEMKIN, R.J.; TOOKER, J.F.

2002-01-01

OAK A271 MUTURING ECRF TECHNOLOGY FOR PLASMA CONTROL. Understanding of the physics of internal transport barriers (ITBs) is being furthered by analysis and comparisons of experimental data from many different tokamaks worldwide. An international database consisting of scalar and 2-D profile data for ITB plasmas is being developed to determine the requirements for the formation and sustainment of ITBs and to perform tests of theory-based transport models in an effort to improve the predictive capability of the models. Analysis using the database indicates that: (a) the power required to form ITBs decreases with increased negative magnetic shear of the target plasma, and: (b) the E x B flow shear rate is close to the linear growth rate of the ITG modes at the time of barrier formation when compared for several fusion devices. Tests of several transport models (JETTO, Weiland model) using the 2-D profile data indicate that there is only limited agreement between the model predictions and the experimental results for the range of plasma conditions examined for the different devices (DIII-D, JET, JT-60U). Gyrokinetic stability analysis (using the GKS code) of the ITB discharges from these devices indicates that the ITG/TEM growth rates decrease with increased negative magnetic shear and that the E x B shear rate is comparable to the linear growth rates at the location of the ITB

Numerical Simulation of a Single-Phase Closed-Loop Thermo-Siphon in LORELEI Test Device

International Nuclear Information System (INIS)

Gitelman, D.; Shenha, H.; Gonnier, Ch.; Tarabelli, D.; Sasson, A.; Weiss, Y.; Katz, M.

2014-01-01

The LORELEI experimental setup in the Jules Horowitz Reactor (JHR) is dedicated for the study of fuel during a Loss of Coolant Accident (LOCA). The main objective of the LORELEI(2) (Light-Water One-Rod Equipment for LOCA Experimental Investigation) is to study the thermal-mechanical behavior of fuel during such an accident and to produce a short half-life fission products source term. In order to study those phenomena, the fuel sample will experience a transient neutron flux field, which in turn will generate a Linear Heat Generation Rate (LHGR) and determine the temperature of the fuel and its cladding, simulating the behavior of the fuel and the cladding during a LOCA accident. In order to reproduce a LOCA-type transient sequence, the experimental test device will be located on a displacement device. The displacement device moves the test device in the flux field in order to generate a representing LHGR in the fuel or temperature of its cladding. The LOCA-type transient sequence has four major features: „h An adiabatic heating of the fuel up to the ballooning and burst occurrence. „h High temperature plateau which will promote clad oxidation. „h Passive precooling by thermal inertia. „h Water re-flooding and quenching. The challenge in the thermo-hydraulic design of the LORELEI test section is in defining a one closed water capsule design that can operate as a thermo-siphon at re-irradiation phase and also can reproduce all LOCA-type transient sequence phases. This design should be validated and verified to fill all safety and regulation requirements. This work aims to investigate fluid flow behavior of a single-phase thermo-siphon in the LORELEI test device, as part of the conceptual design and optimization study. The complexity of the flow field in the LORELEI test device, as a closed-loop thermo-siphon, is due to the opposing forces in the device - buoyancy forces and natural convection flow generated (mainly) by the fuel power in the hot channel

Dense Plasma Focus - From Alternative Fusion Source to Versatile High Energy Density Plasma Source for Plasma Nanotechnology

Science.gov (United States)

Rawat, R. S.

2015-03-01

The dense plasma focus (DPF), a coaxial plasma gun, utilizes pulsed high current electrical discharge to heat and compress the plasma to very high density and temperature with energy densities in the range of 1-10 × 1010 J/m3. The DPF device has always been in the company of several alternative magnetic fusion devices as it produces intense fusion neutrons. Several experiments conducted on many different DPF devices ranging over several order of storage energy have demonstrated that at higher storage energy the neutron production does not follow I4 scaling laws and deteriorate significantly raising concern about the device's capability and relevance for fusion energy. On the other hand, the high energy density pinch plasma in DPF device makes it a multiple radiation source of ions, electron, soft and hard x-rays, and neutrons, making it useful for several applications in many different fields such as lithography, radiography, imaging, activation analysis, radioisotopes production etc. Being a source of hot dense plasma, strong shockwave, intense energetic beams and radiation, etc, the DPF device, additionally, shows tremendous potential for applications in plasma nanoscience and plasma nanotechnology. In the present paper, the key features of plasma focus device are critically discussed to understand the novelties and opportunities that this device offers in processing and synthesis of nanophase materials using, both, the top-down and bottom-up approach. The results of recent key experimental investigations performed on (i) the processing and modification of bulk target substrates for phase change, surface reconstruction and nanostructurization, (ii) the nanostructurization of PLD grown magnetic thin films, and (iii) direct synthesis of nanostructured (nanowire, nanosheets and nanoflowers) materials using anode target material ablation, ablated plasma and background reactive gas based synthesis and purely gas phase synthesis of various different types of

Dense Plasma Focus - From Alternative Fusion Source to Versatile High Energy Density Plasma Source for Plasma Nanotechnology

International Nuclear Information System (INIS)

Rawat, R S

2015-01-01

The dense plasma focus (DPF), a coaxial plasma gun, utilizes pulsed high current electrical discharge to heat and compress the plasma to very high density and temperature with energy densities in the range of 1-10 × 10 10 J/m 3 . The DPF device has always been in the company of several alternative magnetic fusion devices as it produces intense fusion neutrons. Several experiments conducted on many different DPF devices ranging over several order of storage energy have demonstrated that at higher storage energy the neutron production does not follow I 4 scaling laws and deteriorate significantly raising concern about the device's capability and relevance for fusion energy. On the other hand, the high energy density pinch plasma in DPF device makes it a multiple radiation source of ions, electron, soft and hard x-rays, and neutrons, making it useful for several applications in many different fields such as lithography, radiography, imaging, activation analysis, radioisotopes production etc. Being a source of hot dense plasma, strong shockwave, intense energetic beams and radiation, etc, the DPF device, additionally, shows tremendous potential for applications in plasma nanoscience and plasma nanotechnology. In the present paper, the key features of plasma focus device are critically discussed to understand the novelties and opportunities that this device offers in processing and synthesis of nanophase materials using, both, the top-down and bottom-up approach. The results of recent key experimental investigations performed on (i) the processing and modification of bulk target substrates for phase change, surface reconstruction and nanostructurization, (ii) the nanostructurization of PLD grown magnetic thin films, and (iii) direct synthesis of nanostructured (nanowire, nanosheets and nanoflowers) materials using anode target material ablation, ablated plasma and background reactive gas based synthesis and purely gas phase synthesis of various different types of

Self-sustained detachment in the Large Helical Device

International Nuclear Information System (INIS)

Miyazawa, J.; Masuzaki, S.; Sakamoto, R.; Arimoto, H.; Kondo, K.; Tamura, N.; Shoji, M.; Nishiura, M.; Murakami, S.; Funaba, H.; Peterson, B.J.; Sakakibara, S.; Kobayashi, M.; Tanaka, K.; Narihara, K.; Yamada, I.; Morita, S.; Goto, M.; Osakabe, M.; Ashikawa, N.; Morisaki, T.; Nishimura, K.; Yamada, H.; Ohyabu, N.; Komori, A.; Motojima, O.

2006-01-01

Self-sustained detachment has been obtained in the Large Helical Device (LHD). Strong hydrogen gas puffing of ∼200 Pa m 3 s -1 after a density feedback phase detaches the plasma from the divertor plates with high reproducibility. High electron density of over 1 x 10 20 m -3 is sustained without gas puffing until the heating beam stops and a high-density flat top for 2 s has been demonstrated. Throughout the self-sustained detachment phase, the minor radius of the hot plasma column shrinks to ∼90% of the last-closed-flux-surface, which corresponds to the ι-bar ι/2π = 1/q =1 rational surface. This new state has been named the 'Serpens mode', for self-regulated plasma edge 'neath the last-closed-flux-surface. Global energy confinement of the Serpens mode is compared with the international stellarator scaling 1995 (ISS95) and the recently established scaling for high-density LHD plasmas (HD scaling), where shrinking confinement volume and shallow penetration of the heating beams are taken into account. Although the energy confinement of the Serpens mode seems deteriorated compared with ISS95, as in the case of high-density attached plasmas, it is consistent with the HD scaling. This suggests that the energy confinement properties of detached plasmas in LHD are similar to those in high-density attached plasmas

Contributions to the 7th International Conference on plasma surface interactions in controlled fusion devices

International Nuclear Information System (INIS)

1986-01-01

The report contains three papers presented in the 7th International Conference on plasma surface interactions in controlled fusion devices held in Princeton (USA) 5-9 May 1986, all referred to the FT Tokamak

Stable confinement of toroidal electron plasma in an internal conductor device Prototype-Ring Trap

International Nuclear Information System (INIS)

Saitoh, H.; Yoshida, Z.; Watanabe, S.

2005-01-01

A pure electron plasma has been produced in an internal conductor device Prototype-Ring Trap (Proto-RT). The temporal evolution of the electron plasma was investigated by the measurement of electrostatic fluctuations. Stable confinement was realized when the potential profile adjusted to match the magnetic surfaces. The confinement time varies as a function of the magnetic field strength and the neutral gas pressure, and is comparable to the diffusion time of electrons determined by the classical collisions with neutral gas. Although the addition of a toroidal magnetic field stabilized the electrostatic fluctuation of the plasma, the effects of the magnetic shear shortened the stable confinement time, possibly because of the obstacles of coil support structures

Suppression of hydrogenated carbon film deposition by scavenger techniques and their application to the tritium inventory control of fusion devices

International Nuclear Information System (INIS)

Tabares, F.L.; Tafalla, D.; Tanarro, I.; Herrero, V.J.; Islyaikin, A.; Maffiotte, C.

2002-01-01

The well-known radical and ion scavenger techniques of application in amorphous hydrogenated carbon film deposition studies are investigated in relation to the mechanism of tritium and deuterium co-deposition in carbon-dominated fusion devices. A particularly successful scheme results from the injection of nitrogen into methane/hydrogen plasmas for conditions close to those prevailing in the divertor region of present fusion devices. A complete suppression of the a-C : H film deposition has been achieved for N 2 /CH 4 ratios close to one in methane (5%)/hydrogen DC plasma. The implications of these findings in the tritium retention control in future fusion reactors are addressed. (author). Letter-to-the-editor

A very sensitive ion collection device for plasma-laser characterization.

Science.gov (United States)

Cavallaro, S; Torrisi, L; Cutroneo, M; Amato, A; Sarta, F; Wen, L

2012-06-01

In this paper a very sensitive ion collection device, for diagnostic of laser ablated-target plasma, is described. It allows for reducing down to few microvolts the signal threshold at digital scope input. A standard ion collector is coupled to a transimpedance amplifier, specially designed, which increases data acquisition sensitivity by a gain ≈1100 and does not introduce any significant distortion of input signal. By time integration of current intensity, an amount of charge as small as 2.7 × 10(-2) pC can be detected for photopeak events.

Hard X-ray sources from miniature plasma focus devices

International Nuclear Information System (INIS)

Raspa, V.; Silva, P.; Moreno, J.; Zambra, M.; Soto, L.

2004-01-01

As first stage of a program to design a repetitive pulsed radiation generator for industrial applications, two miniature plasma foci have been designed and constructed at the Chilean commission of nuclear energy. The devices operate at an energy level of the order of tens of joules (PF-50 J, 160 nF capacitor bank, 20-35 kV, 32-100 J, ∼ 150 ns time to peak current) and hundred of joules (PF-400 J, 880 nF, 20-35 kV, 176-539 J, ∼ 300 ns time to peak current). Hard X-rays are being studied in these devices operating with hydrogen. Images of metallic plates with different thickness were obtained on commercial radiographic film, Agfa Curix ST-G2, in order to characterize the energy of the hard X-ray outside of the discharge chamber of PF-400 J. An effective energy of the order of 90 keV was measured under those conditions. X ray images of different metallic objects also have been obtained. (authors)

Hard X-ray sources from miniature plasma focus devices

Energy Technology Data Exchange (ETDEWEB)

Raspa, V. [Buenos Aires Univ., PLADEMA, CONICET and INFIP (Argentina); Silva, P.; Moreno, J.; Zambra, M.; Soto, L. [Comision Chilena de Energia Nuclear, Santiago (Chile)

2004-07-01

As first stage of a program to design a repetitive pulsed radiation generator for industrial applications, two miniature plasma foci have been designed and constructed at the Chilean commission of nuclear energy. The devices operate at an energy level of the order of tens of joules (PF-50 J, 160 nF capacitor bank, 20-35 kV, 32-100 J, {approx} 150 ns time to peak current) and hundred of joules (PF-400 J, 880 nF, 20-35 kV, 176-539 J, {approx} 300 ns time to peak current). Hard X-rays are being studied in these devices operating with hydrogen. Images of metallic plates with different thickness were obtained on commercial radiographic film, Agfa Curix ST-G2, in order to characterize the energy of the hard X-ray outside of the discharge chamber of PF-400 J. An effective energy of the order of 90 keV was measured under those conditions. X ray images of different metallic objects also have been obtained. (authors)

Simulation analysis of dust-particle transport in the peripheral plasma in the Large Helical Device

International Nuclear Information System (INIS)

Shoji, Mamoru; Masuzaki, Suguru; Kawamura, Gakushi; Yamada, Hiroshi; Tanaka, Yasunori; Uesugi, Yoshihiko; Pigarov, Alexander Yu.; Smirnov, Roman D.

2014-01-01

The function of the peripheral plasma in the Large Helical Device (LHD) on transport of dusts is investigated using a dust transport simulation code (DUSTT) in a non-axisymmetric geometry. The simulation shows that the transport of the dusts is dominated by the plasma flow (mainly by ion drag force) formed in the peripheral plasma. The trajectories of dusts are investigated in two probable situations: release of spherical iron dusts from the inboard side of the torus, and drop of spherical carbon dusts from a divertor plate installed near an edge of an upper port. The trajectories in these two situations are calculated in various sized dust cases. From a viewpoint of protection of the main plasma from dust penetration, it proves that there are two functions in the LHD peripheral plasma. One is sweeping of dusts by the effect of the plasma flow in the divertor legs, and another one is evaporation/sublimation of dusts by heat load onto the dusts in the ergodic layer. (author)

Investigation of the neutron production phases of a large plasma focus device

International Nuclear Information System (INIS)

Hayd, A.; Maurer, M.; Meinke, P.; Herold, H.; Bertalot, L.; Deutsch, R.; Grauf, W.; Jaeger, U.; Kaeppeler, H.J.; Lepper, F.; Oppenlaender, T.; Schmidt, H.; Schmidt, R.; Schwarz, J.; Schwoerer, K.; Shakhatre, M.

1982-09-01

Plasma dynamic behavior and neutron production in large focus devices with pinch currents of approximately 1 MA have been studied with theoretical as well as experimental methods. For treating turbulent plasma motion, a hybrid code based on the analytical computer algorithm REDUCE was developed. Experimental diagnostics include schlieren photographs, reaction proton localization with pinhole cameras and neutron measurements with Ag-counters and scintillators. Calculated and measured data concern the 280 kJ, 60 kV operational mode of the POSEIDON plasma focus. It is shown that for large pinch currents ( > 500 kA), neutron emission also appears before m = 0 onset in the intermediate phase. This part of the neutron production becomes predominant for very large currents. The lifetime of this intermediate phase strongly increases with increasing current. According to theory, the late phase of the focus is governed by strong turbulence phenomena. The lifetime of the turbulence packets is approximately 150 ns and seems to explain the long lasting neutron emission in this phase. (orig.)

Proceedings of 1999 U.S./Japan Workshop (99FT-05) On High Heat Flux Components and Plasma Surface Interactions for Next Fusion Devices

International Nuclear Information System (INIS)

NYGREN, RICHARD E.; STAVROS, DIANA T.

2000-01-01

The 1999 US-Japan Workshop on High Heat Flux Components and Plasma Surface Interactions in Next Step Fusion Devices was held at the St. Francis Hotel in Santa Fe, New Mexico, on November 1-4, 1999. There were 42 presentations as well as discussion on technical issues and planning for future collaborations. The participants included 22 researchers from Japan and the United States as well as seven researchers from Europe and Russia. There have been important changes in the programs in both the US and Japan in the areas of plasma surface interactions and plasma facing components. The US has moved away from a strong focus on the ITER Project and has introduced new programs on use of liquid surfaces for plasma facing components, and operation of NSTX has begun. In Japan, the Large Helical Device began operation. This is the first large world-class confinement device operating in a magnetic configuration different than a tokamak. In selecting the presentations for this workshop, the organizers sought a balance between research in laboratory facilities or confinement devices related to plasma surface interactions and experimental research in the development of plasma facing components. In discussions about the workshop itself, the participants affirmed their preference for a setting where ''work-in-progress'' could be informally presented and discussed

Output channel design for collecting closely-spaced particle streams from spiral inertial separation devices

Directory of Open Access Journals (Sweden)

Caffiyar Mohamed Yousuff

2017-08-01

Full Text Available Recent advances in inertial microfluidics designs have enabled high throughput, label-free separation of cells for a variety of bioanalytical applications. Various device configurations have been proposed for binary separation with a focus on enhancing the separation distance between particle streams to improve the efficiency of separate particle collection. These configurations have not demonstrated scaling beyond 3 particle streams either because the channel width is a constraint at the collection outlets or particle streams would be too closely spaced to be collected separately. We propose a method to design collection outlets for inertial focusing and separation devices which can collect closely-spaced particle streams and easily scale to an arbitrary number of collection channels without constraining the outlet channel width, which is the usual cause of clogging or cell damage. According to our approach, collection outlets are a series of side-branching channels perpendicular to the main channel of egress. The width and length of the outlets can be chosen subject to constraints from the position of the particle streams and fluidic resistance ratio computed from fluid dynamics simulations. We show the efficacy of this approach by demonstrating a successful collection of upto 3 particle streams of 7μm, 10μm and 15μm fluorescent beads which have been focused and separated by a spiral inertial device with a separation distance of only 10μm -15μm. With a throughput of 1.8mL/min, we achieved collection efficiency exceeding 90% for each particle at the respective collection outlet. The flexibility to use wide collection channels also enabled us to fabricate the microfluidic device with an epoxy mold that was created using xurography, a low cost, and imprecise fabrication technique.

Use of a dry-plasma collection device to overcome problems with storage and transportation of blood samples for epidemiology studies in developing countries.

Science.gov (United States)

Nurgalieva, Z Z; Almuchambetova, R; Machmudova, A; Kapsultanova, D; Osato, M S; Peacock, J; Zoltek, R P; Marchildon, P A; Graham, D Y; Zhangabylov, A

2000-11-01

Studies are difficult in areas lacking modern facilities due to the inability to reliably collect, store, and ship samples. Thus, we sought to evaluate the use of a dry plasma collection device for seroepidemiology studies. Plasma was obtained by fingerstick using a commercial dry plasma collection device (Chemcard Plasma Collection Device) and serum (venipuncture) from individuals in Kazakhstan. Plasma samples were air dried for 15 min and then stored desiccated in foil zip-lock pouches at 4 to 6 degrees C and subsequently shipped to the United States by air at ambient temperature. Serum samples remained frozen at -20 degrees C until assayed. Helicobacter pylori status was determined by enzyme-linked immunosorbent assay (HM-CAP EIA) for the dry plasma and the serum samples. The results were concordant in 250 of the 289 cases (86.5%). In 25 cases (8.6%), the dry plasma samples gave indeterminate results and could not be retested because only one sample was collected. Five serum samples were positive, and the corresponding dry plasma samples were negative; one serum sample was negative, and the corresponding plasma sample was positive. The relative sensitivity and specificity of the Chemcard samples to serum were 97.6 and 97.9%, respectively, excluding those with indeterminate results. Repeated freeze-thawing had no adverse effect on the accuracy of the test. We found the dry plasma collection device to provide an accurate and practical alternative to serum when venipuncture may be difficult or inconvenient and sample storage and handling present difficulties, especially for seroepidemiologic studies in rural areas or developing countries and where freeze-thawing may be unavoidable.

Performance analyses of Elmo Bumpy Torus plasmas and plasma support systems

International Nuclear Information System (INIS)

Fenstermacher, M.E.

1979-01-01

The development and applcation of the OASIS Code (Operational Analysis of ELMO Bumpy Torus Support and Ignition Systems) for the study of EBT device and plasma performance are presented. The code performs a time-independent, zero-dimensional self-consistent calculation of plasma and plasmasupport systems parameters for the physics and engineering of EBT devices. The features of OASIS modeling for the EBT plasma include: (1) particle balance of the bulk toroidal and electron ring plasma components for experimental (H-H, D-D, He-He etc.) as well as reactor (D-T) devices; (2) energy balance in the bulk and ring plasmas for externally heated or ignition devices; (3) alpha particle effects for reactor devices; (4) auxiliary heating effects, including microwave (ECRH), RF heating (e.g., ICRH), and neutral beam methods; and (5) ignition conditions, including fusion power, alpha power and neutron wall loading. The performance studies using OASIS focussed on variation in plasma and device size and on microwave input power and frequency. An additional study was performed to determine the characteristics of an EBT reactor proof-of-principle device operated with a deuterium-tritium plasma. Sensitivity studies were performed for variation in the input microwave power sharing fractions and the dependence of the bulk n tau scaling law on bulk electron temperature

Radioactive gas storage device

International Nuclear Information System (INIS)

Seki, Eiji; Kobayashi, Yoshihiro.

1989-01-01

The present invention concerns a device of ionizing radioactive gases to be processed in gaseous nuclear fission products in nuclear fuel reprocessing plants, etc., and injecting them into metal substrates for storage. The device comprises a vessel for a tightly closed type outer electrode in which gases to be processed are introduced, an electrode disposed to the inside of the vessel and the target material, a high DC voltage power source for applying high voltage to the electrodes, etc. There are disposed a first electric discharging portion for preparting discharge plasma for ion injection of different electrode distance and a second electric discharging portion for causing stable discharge between the vessel and the electrode. The first electric discharging portion for the ion injection provides an electrode distance suitable to acceleration sputtering and the second electric discharging portion is used for stable discharge. Accordingly, if the gas pressure in the radioactive gas storage device is reduced by the external disturbance, etc., since the second electric discharging portion satisfies the electric discharging conditions, the device can continue electric discharge. (K.M.)

Aquaregia and Oxygen Plasma Treatments on Fluorinated Tin Oxide for Assembly of PLEDs Devices Using OC1C10-PPV as Emissive Polymer

Directory of Open Access Journals (Sweden)

Emerson Roberto SANTOS

2009-02-01

Full Text Available In this work were carried out treatments with oxygen plasma and aquaregia on fluorinated tin oxide (FTO films varying the treatment times. After treatments, the samples were analyzed by techniques measurements: sheet resistance, thickness, Hall effect, transmittance and superficial roughness. Devices using FTO/PEDOT:PSS/OC1C10-PPV/Al were assembled. In this experiment some variations were observed by sheet resistance and thickness and Hall effect measurements indicated most elevated carriers concentration and resistivity for aquaregia than that oxygen plasma. The roughness was elevated for the first minutes with treatment by aquaregia too. In the I-V curves the aquaregia devices presented the lowest threshold voltage for 30 minutes and devices treated by oxygen plasma presented a behavior most resistivity different of typical curves for PLEDs devices.

Data on rotating plasma operation in Tornado traps

International Nuclear Information System (INIS)

Lehnert, B.

1976-01-01

Rotating plasma operation in spiral coil 'Tornado' traps provides a unique combination of confinement and heating properties. Such a system consists of a closed and compact magnetic bottle to which the crossed-field technique can be applied, in absence of end insulators and their critical velocity limitation effect. This should make possible the generation and heating of fully ionized plasmas by simple means, within a large range of ion densities, temperatures, and rotational velocities. Provided that stable operation becomes possible at high temperatures, it is likely that Tornado traps can be used as strong neutron sources of moderately large dimensions and technically realizable parameter values. Some detailed data and operation ranges are given for the 'Tornado 650' device in Leningrad, and for a somewhat larger device to be operated as neutron source. (Auth.)

Plasma electron density measurement with multichannel microwave interferometer on the HL-1 tokamak device

International Nuclear Information System (INIS)

Xu Deming; Zhang Hongyin; Liu Zetian; Ding Xuantong; Li Qirui; Wen Yangxi

1989-11-01

A multichannel microwave interferometer which is composed of different microwave interferometers (one 2 mm band, one 4 mm band and two 8 mm band) has been used to measure the plasma electron density on HL-1 tokamak device. The electron density approaching to 5 x 10 13 cm -3 is measured by a 2 mm band microwave interferometer. In the determinable range, the electron density profile in the cross-section on HL-1 device has been measured by this interferometer. A microcomputer data processing system is also developed

On non-equilibrium atmospheric pressure plasma jets and plasma bullet

Science.gov (United States)

Lu, Xinpei

2012-10-01

Because of the enhanced plasma chemistry, atmospheric pressure nonequilibrium plasmas (APNPs) have been widely studied for several emerging applications such as biomedical applications. For the biomedical applications, plasma jet devices, which generate plasma in open space (surrounding air) rather than in confined discharge gaps only, have lots of advantages over the traditional dielectric barrier discharge (DBD) devices. For example, it can be used for root canal disinfection, which can't be realized by the traditional plasma device. On the other hand, currently, the working gases of most of the plasma jet devices are noble gases or the mixtures of the noble gases with small amount of O2, or air. If ambient air is used as the working gas, several serious difficulties are encountered in the plasma generation process. Amongst these are high gas temperatures and disrupting instabilities. In this presentation, firstly, a brief review of the different cold plasma jets developed to date is presented. Secondly, several different plasma jet devices developed in our lab are reported. The effects of various parameters on the plasma jets are discussed. Finally, one of the most interesting phenomena of APNP-Js, the plasma bullet is discussed and its behavior is described. References: [1] X. Lu, M. Laroussi, V. Puech, Plasma Sources Sci. Technol. 21, 034005 (2012); [2] Y. Xian, X. Lu, S. Wu, P. Chu, and Y. Pan, Appl. Phys. Lett. 100, 123702 (2012); [3] X. Pei, X. Lu, J. Liu, D. Liu, Y. Yang, K. Ostrikov, P. Chu, and Y. Pan, J. Phys. D 45, 165205 (2012).

Atmospheric pressure plasma produced inside a closed package by a dielectric barrier discharge in Ar/CO2 for bacterial inactivation of biological samples

International Nuclear Information System (INIS)

Chiper, A S; Chen, W; Stamate, E; Mejlholm, O; Dalgaard, P

2011-01-01

The generation and evaluation of a dielectric barrier discharge produced inside a closed package made of a commercially available packaging film and filled with gas mixtures of Ar/CO 2 at atmospheric pressure is reported. The discharge parameters were analysed by electrical measurements and optical emission spectroscopy in two modes of operation: trapped gas atmosphere and flowing gas atmosphere. Gas temperature was estimated using the OH(A-X) emission spectrum and the rotational temperature reached a saturation level after a few minutes of plasma running. The rotational temperature was almost three times higher in the Ar/CO 2 plasma compared with an Ar plasma. The efficiency of the produced plasma for the inactivation of bacteria on food inside the closed package was investigated.

Plasma focus breeder

International Nuclear Information System (INIS)

Ikuta, Kazunari.

1981-09-01

Instead of using linear accelerators, it is possible to breed fissile fuels with the help of high current plasma focus device. A mechanism of accelerating proton beam in plasma focus device to high energy would be a change of inductance in plasma column because of rapid growth of plasma instability. A possible scheme of plasma focus breeder is also proposed. (author)

Lightweight Portable Plasma Medical Device - Plasma Engineering Research Laboratory

Science.gov (United States)

2015-12-01

monocytic leukemia cancer cells ( THP -1) were also tested and the results 19 demonstrate that a preference for apoptosis in plasma treated THP -1...unanswered questions. We have tested the effects of indirect exposure of non-thermal air plasma on monocytic leukemia cancer cells ( THP -1) and deciphering... tested and the results are shown in Fig. above. The results demonstrate that a preference for apoptosis in plasma treated THP -1 cells under

Proceedings of 1999 U.S./Japan Workshop (99FT-05) On High Heat Flux Components and Plasma Surface Interactions for Next Fusion Devices

Energy Technology Data Exchange (ETDEWEB)

NYGREN,RICHARD E.; STAVROS,DIANA T.

2000-06-01

The 1999 US-Japan Workshop on High Heat Flux Components and Plasma Surface Interactions in Next Step Fusion Devices was held at the St. Francis Hotel in Santa Fe, New Mexico, on November 1-4, 1999. There were 42 presentations as well as discussion on technical issues and planning for future collaborations. The participants included 22 researchers from Japan and the United States as well as seven researchers from Europe and Russia. There have been important changes in the programs in both the US and Japan in the areas of plasma surface interactions and plasma facing components. The US has moved away from a strong focus on the ITER Project and has introduced new programs on use of liquid surfaces for plasma facing components, and operation of NSTX has begun. In Japan, the Large Helical Device began operation. This is the first large world-class confinement device operating in a magnetic configuration different than a tokamak. In selecting the presentations for this workshop, the organizers sought a balance between research in laboratory facilities or confinement devices related to plasma surface interactions and experimental research in the development of plasma facing components. In discussions about the workshop itself, the participants affirmed their preference for a setting where ''work-in-progress'' could be informally presented and discussed.

Realization of write-once-read-many-times memory device with O{sub 2} plasma-treated indium gallium zinc oxide thin film

Energy Technology Data Exchange (ETDEWEB)

Liu, P., E-mail: liup0013@ntu.edu.sg; Chen, T. P., E-mail: echentp@ntu.edu.sg; Li, X. D.; Wong, J. I. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Liu, Z. [School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006 (China); Liu, Y. [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Leong, K. C. [GLOBALFOUNDRIES Singapore Pte Ltd, 60 Woodlands Industrial Park D Street 2, Singapore 738406 (Singapore)

2014-01-20

A write-once-read-many-times (WORM) memory devices based on O{sub 2} plasma-treated indium gallium zinc oxide (IGZO) thin films has been demonstrated. The device has a simple Al/IGZO/Al structure. The device has a normally OFF state with a very high resistance (e.g., the resistance at 2 V is ∼10{sup 9} Ω for a device with the radius of 50 μm) as a result of the O{sub 2} plasma treatment on the IGZO thin films. The device could be switched to an ON state with a low resistance (e.g., the resistance at 2 V is ∼10{sup 3} Ω for the radius of 50 μm) by applying a voltage pulse (e.g., 10 V/1 μs). The WORM device has good data-retention and reading-endurance capabilities.

DLTS Analysis and Interface Engineering of Solution Route Fabricated Zirconia Based MIS Devices Using Plasma Treatment

Science.gov (United States)

Kumar, Arvind; Mondal, Sandip; Koteswara Rao, K. S. R.

2018-02-01

In this work, we have fabricated low-temperature sol-gel spin-coated and oxygen (O2) plasma treated ZrO2 thin film-based metal-insulator-semiconductor devices. To understand the impact of plasma treatment on the Si/ZrO2 interface, deep level transient spectroscopy measurements were performed. It is reported that the interface state density ( D it) comes down to 7.1 × 1010 eV-1 cm-2 from 4 × 1011 eV-1 cm-2, after plasma treatment. The reduction in D it is around five times and can be attributed to the passivation of oxygen vacancies near the Si/ZrO2 interface, as they try to relocate near the interface. The energy level position ( E T) of interfacial traps is estimated to be 0.36 eV below the conduction band edge. The untreated ZrO2 film displayed poor leakage behavior due to the presence of several traps within the film and at the interface; O2 plasma treated films show improved leakage current density as they have been reduced from 5.4 × 10-8 A/cm2 to 1.98 × 10-9 A/cm2 for gate injection mode and 6.4 × 10-8 A/cm2 to 6.3 × 10-10 A/cm2 for substrate injection mode at 1 V. Hence, we suggest that plasma treatment might be useful in future device fabrication technology.

Turbulence measurements in fusion plasmas

International Nuclear Information System (INIS)

Conway, G D

2008-01-01

Turbulence measurements in magnetically confined toroidal plasmas have a long history and relevance due to the detrimental role of turbulence induced transport on particle, energy, impurity and momentum confinement. The turbulence-the microscopic random fluctuations in particle density, temperature, potential and magnetic field-is generally driven by radial gradients in the plasma density and temperature. The correlation between the turbulence properties and global confinement, via enhanced diffusion, convection and direct conduction, is now well documented. Theory, together with recent measurements, also indicates that non-linear interactions within the turbulence generate large scale zonal flows and geodesic oscillations, which can feed back onto the turbulence and equilibrium profiles creating a complex interdependence. An overview of the current status and understanding of plasma turbulence measurements in the closed flux surface region of magnetic confinement fusion devices is presented, highlighting some recent developments and outstanding problems.

Effect of inserted metal at anode tip on formation of pulsed X-ray emitting zone of plasma focus device

Science.gov (United States)

Miremad, Seyed Milad; Shirani Bidabadi, Babak

2018-04-01

The effect of the anode's insert material of a plasma focus device on the properties of X-ray emission zone was studied. Inserts were fabricated out of six different materials including aluminum, copper, zinc, tin, tungsten, and lead to cover a wide range of atomic numbers. For each anode's insert material at different gas pressures and different voltages, the shape of X-ray emission zone was recorded by three pinhole cameras, which were installed on sidewall and roof of the chamber of plasma focus device. The results indicated that by changing the gas pressure and the charge voltage of capacitor, the X-ray source of plasma focus emerges with different forms as a concentrated column or conical shape with sharp or cloudy edges. These structures are in the form of a combination of plasma emission and anode-tip emission with different intensities. These observations indicate that the material of the anode-tip especially affects the structure of X-ray emission zone.

Neutron measuring device

International Nuclear Information System (INIS)

Hatayama, Akiyoshi; Seki, Eiji; Kita, Yoshio; Nishitani, Takeo.

1993-01-01

The device of the present invention concerns measurement for neutrons in a tokamak type thermonuclear device and it can measure total amount of generated neutrons accurately throughout the operation period even if an error is caused in counted values by plasma disruption. That is, the device comprises (1) a means for detecting presence or absence of occurrence of plasma disruption and the time for the initiation of the occurrence, (2) a first data processing means for processing detection signals, (3) a means for detecting neutrons generated in plasmas and (4) a second data processing means for calculating integrated values for the number of neutrons generated from the start to the completion of electric discharge when no disruption occurs and calculating integrated values for the number of generated neutrons from the start of electric discharge to the time at the initiation of occurrence of the disruption when disruption is present. In the thus constituted device, even if an error is caused by frequent occurrence of plasma disruption, total time integrated amount of neutrons generated in the plasmas can be measured accurately. (I.S.)

High-density plasma etching of III-nitrides: Process development, device applications and damage remediation

Science.gov (United States)

Singh, Rajwinder

Plasma-assisted etching is a key technology for III-nitride device fabrication. The inevitable etch damage resulting from energetic pattern transfer is a challenge that needs to be addressed in order to optimize device performance and reliability. This dissertation focuses on the development of a high-density inductively-coupled plasma (ICP) etch process for III-nitrides, the demonstration of its applicability to practical device fabrication using a custom built ICP reactor, and development of techniques for remediation of etch damage. A chlorine-based standard dry etch process has been developed and utilized in fabrication of a number of electronic and optoelectronic III-nitride devices. Annealing studies carried out at 700°C have yielded the important insight that the annealing time necessary for making good-quality metal contacts to etch processed n-GaN is very short (water, prior to metallization, removes some of the etch damage and is helpful in recovering contact quality. In-situ treatment consisting of a slow ramp-down of rf bias at the end of the etch is found to achieve the same effect as the ex-situ treatment. This insitu technique is significantly advantageous in a large-scale production environment because it eliminates a process step, particularly one involving treatment in hydrochloric acid. ICP equipment customization for scaling up the process to full 2-inch wafer size is described. Results on etching of state of the art 256 x 256 AlGaN focal plane arrays of ultraviolet photodetectors are reported, with excellent etch uniformity over the wafer area.

Preliminary Results Of A 600 Joules Small Plasma Focus Device

International Nuclear Information System (INIS)

Lee, S. H.; Yap, S. L.; Wong, C. S.

2009-01-01

Preliminary results of a 600 J (3.7 μF, 18 kV) Mather type plasma focus device operated at low pressure will be presented. The discharge is formed between a solid anode with length of 6 cm and six symmetrically and coaxially arranged cathode rods of same lengths. The cathode base is profiled in a knife-edge design and a set of coaxial plasma gun are attached to it in order to initiate the breakdown and enhance the current sheath formation. The experiments have been performed in argon gas under a low pressure condition of several microbars. The discharge current and the voltage across the electrodes during the discharge are measured with high voltage probe and current coil. The current and voltage characteristics are used to determine the possible range of operating pressure that gives good focusing action. At a narrow pressure regime of 9.0±0.5 μbar, focusing action is observed with good reproducibility. Preliminary result of ion beam energy is presented. More work will be carried out to investigate the radiation output.

Efficiency comparison of 3 kinds of arterial puncture closing devices

International Nuclear Information System (INIS)

Feng Xiaodi; Jin Xian; Chen Yueguang; Xiao Hongbing; Yu Qiang; Chen Chengjun; Zhang Dadong

2007-01-01

Objective: To evaluate the efficiencies of arterial puncture closing devices (APCDs) including Angioseal, Perclose and Boomerang in patients undergone coronary angiography or percutaneous vascular interventions. Methods: 1497 patients underwent cardiac catheterization procedures were divided into manual compression group(639 cases) and APCDs closure group (576 cases with Angioseal, 151 cases Perclose and 11.3 cases of Boomerang). The times of maneuver, hemorrhage complication and other rare complications were assessed, recorded and compared. Results: The times for maneuver of standard manual compression group, Angioseal group, Perclose group and Boomerang group were (21.4±2.7) h, (3.5±2.3) h, (3.7± 2.6) h and (3.9±2.8) h respectively. The APCDs could obviously reduce bed rest time in comparing to that of manual compression. The rates of failure of the operations were 2.7%, 1.4%, 8.6% and 3.5% (P =0.006, P<0.001); and the rates of hemorrhage were 9.2%, 5.8%, 12.6% and 8.0% respectively for each of the four mentioned groups (P=0.005). Except the failure operations, the incidence of hemorrhage complications among the groups showed no significant differences. Conclusion: Application of APCDs to close the puncture site can significantly reduce the bed rest time, but not the incidence of hemorrhage complications. (authors)

Steady-state operation of magnetic fusion devices: Plasma control and plasma facing components. Report on the IAEA technical committee meeting held at Fukuoka, 25-29 October 1999

International Nuclear Information System (INIS)

Engelmann, F.

2000-01-01

An IAEA Technical Committee Meeting on Steady-State Operation of Magnetic Fusion Devices - Plasma Control and Plasma Facing Components was held at Fukuoka, Japan, from 25 to 29 October 1999. The meeting was the second IAEA Techical Committee Meeting on the subject, following the one held at Hefei, China, a year earlier. The meeting was attended by over 150 researchers from 10 countries

Silicon Nitride Deposition for Flexible Organic Electronic Devices by VHF (162 MHz)-PECVD Using a Multi-Tile Push-Pull Plasma Source.

Science.gov (United States)

Kim, Ki Seok; Kim, Ki Hyun; Ji, You Jin; Park, Jin Woo; Shin, Jae Hee; Ellingboe, Albert Rogers; Yeom, Geun Young

2017-10-19

Depositing a barrier film for moisture protection without damage at a low temperature is one of the most important steps for organic-based electronic devices. In this study, the authors investigated depositing thin, high-quality SiN x film on organic-based electronic devices, specifically, very high-frequency (162 MHz) plasma-enhanced chemical vapor deposition (VHF-PECVD) using a multi-tile push-pull plasma source with a gas mixture of NH 3 /SiH 4 at a low temperature of 80 °C. The thin deposited SiN x film exhibited excellent properties in the stoichiometry, chemical bonding, stress, and step coverage. Thin film quality and plasma damage were investigated by the water vapor transmission rate (WVTR) and by electrical characteristics of organic light-emitting diode (OLED) devices deposited with SiN x , respectively. The thin deposited SiN x film exhibited a low WVTR of 4.39 × 10 -4  g (m 2 · day) -1 for a single thin (430 nm thick) film SiN x and the electrical characteristics of OLED devices before and after the thin SiN x film deposition on the devices did not change, which indicated no electrical damage during the deposition of SiN x on the OLED device.

A novel method of sensing temperatures of magnet coils of SINP-MaPLE plasma device

International Nuclear Information System (INIS)

Pal, A M; Bhattacharya, S; Biswas, S; Basu, S; Pal, R

2014-01-01

A set of 36 magnet coils is used to produce a continuous, uniform magnetic field of about 0.35 Tesla inside the vacuum chamber of the MaPLE Device, a linear laboratory plasma device (3 m long and 0.30 m in diameter) built for studying basic magnetized plasma physics phenomena. To protect the water cooled-coils from serious damage due to overheating temperatures of all the coils are monitored electronically using low cost temperature sensor IC chips, a technique first being used in similar magnet system. Utilizing the Parallel Port of a Personal Computer a novel scheme is used to avoid deploying microprocessor that is associated with involved circuitry and low level programming to address and control the large number of sensors. The simple circuits and a program code to implement the idea are developed, tested and presently in operation. The whole arrangement comes out to be not only attractive, but also simple, economical and easy to install elsewhere

Publisher's Note: ''The MaPLE device of Saha Institute of Nuclear Physics: Construction and its plasma aspects'' [Rev. Sci. Instrum. 81, 073507 (2010)

International Nuclear Information System (INIS)

Pal, Rabindranath; Biswas, Subir; Basu, Subhasis; Chattopadhyay, Monobir; Basu, Debjyoti; Chaudhuri, Manis

2010-01-01

The Magnetized Plasma Linear Experimental (MaPLE) device is a low cost laboratory plasma device at Saha Institute of Nuclear Physics fabricated in-house with the primary aim of studying basic plasma physics phenomena such as plasma instabilities, wave propagation, and their nonlinear behavior in magnetized plasma regime in a controlled manner. The machine is specially designed to be a versatile laboratory device that can provide a number of magnetic and electric scenario to facilitate such studies. A total of 36 number of 20-turn magnet coils, designed such as to allow easy handling, is capable of producing a uniform, dc magnetic field of about 0.35 T inside the plasma chamber of diameter 0.30 m. Support structure of the coils is planned in an innovative way facilitating straightforward fabrication and easy positioning of the coils. Further special feature lies in the arrangement of the spacers between the coils that can be maneuvered rather easily to create different magnetic configurations. Various methods of plasma production can be suitably utilized according to the experimental needs at either end of the vacuum vessel. In the present paper, characteristics of a steady state plasma generated by electron cyclotron resonance method using 2.45 GHz microwave power are presented. Scans using simple probe drives revealed that a uniform and long plasma column having electron density ∼ 3–5×1010 cm−3 and temperature ∼ 7–10 eV, is formed in the center of the plasma chamber which is suitable for wave launching experiments.

Heat and momentum transport of ion internal transport barrier plasmas on Large Helical Device

International Nuclear Information System (INIS)

Nagaoka, K.; Ida, K.; Yoshinuma, M.

2010-11-01

The peaked ion-temperature profile with steep gradient so called ion internal transport barrier (ion ITB) was formed in the neutral beam heated plasmas on the Large Helical Device (LHD) and the high-ion-temperature regime of helical plasmas has been significantly extended. The ion thermal diffusivity in the ion ITB plasma decreases down to the neoclassical transport level. The heavy ion beam probe (HIBP) observed the smooth potential profile with negative radial electric field (ion root) in the core region where the ion thermal diffusivity decreases significantly. The large toroidal rotation was also observed in the ion ITB core and the transport of toroidal momentum was analyzed qualitatively. The decrease of momentum diffusivity with ion temperature increase was observed in the ion ITB core. The toroidal rotation driven by ion temperature gradient so called intrinsic rotation is also identified. (author)

Bi-Maxwellian electron energy distribution function in the vicinity of the last closed flux surface in fusion plasma

Czech Academy of Sciences Publication Activity Database

Popov, T.S.V.K.; Dimitrova, Miglena; Pedrosa, M. A.; López-Bruna, D.; Horáček, Jan; Kovačič, J.; Dejarnac, Renaud; Stöckel, Jan; Aftanas, Milan; Böhm, Petr; Bílková, Petra; Hidalgo, C.; Pánek, Radomír

2015-01-01

Roč. 57, č. 11 (2015), č. článku 115011. ISSN 0741-3335 R&D Projects: GA ČR(CZ) GAP205/12/2327; GA MŠk(CZ) LM2011021 Institutional support: RVO:61389021 Keywords : COMPASS tokamak, parallel power flux density * TJ-II stellarator * bi-Maxwellian EEDF * last closed flux surface * SOL * parallel power flux density Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.404, year: 2015

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

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.

Three-dimensional two-fluid Braginskii simulations of the large plasma device

Energy Technology Data Exchange (ETDEWEB)

Fisher, Dustin M., E-mail: dustin.m.fisher.gr@dartmouth.edu; Rogers, Barrett N., E-mail: barrett.rogers@dartmouth.edu [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Rossi, Giovanni D.; Guice, Daniel S.; Carter, Troy A. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)

2015-09-15

The Large Plasma Device (LAPD) is modeled using the 3D Global Braginskii Solver code. Comparisons to experimental measurements are made in the low-bias regime in which there is an intrinsic E × B rotation of the plasma. In the simulations, this rotation is caused primarily by sheath effects and may be a likely mechanism for the intrinsic rotation seen in LAPD. Simulations show strong qualitative agreement with the data, particularly the radial dependence of the density fluctuations, cross-correlation lengths, radial flux dependence outside of the cathode edge, and camera imagery. Kelvin Helmholtz (KH) turbulence at relatively large scales is the dominant driver of cross-field transport in these simulations with smaller-scale drift waves and sheath modes playing a secondary role. Plasma holes and blobs arising from KH vortices in the simulations are consistent with the scale sizes and overall appearance of those in LAPD camera images. The addition of ion-neutral collisions in the simulations at previously theorized values reduces the radial particle flux by about a factor of two, from values that are somewhat larger than the experimentally measured flux to values that are somewhat lower than the measurements. This reduction is due to a modest stabilizing contribution of the collisions on the KH-modes driving the turbulent transport.

Plasma particle sources due to interactions with neutrals in a turbulent scrape-off layer of a toroidally confined plasma

Science.gov (United States)

Thrysøe, A. S.; Løiten, M.; Madsen, J.; Naulin, V.; Nielsen, A. H.; Rasmussen, J. Juul

2018-03-01

The conditions in the edge and scrape-off layer (SOL) of magnetically confined plasmas determine the overall performance of the device, and it is of great importance to study and understand the mechanics that drive transport in those regions. If a significant amount of neutral molecules and atoms is present in the edge and SOL regions, those will influence the plasma parameters and thus the plasma confinement. In this paper, it is displayed how neutrals, described by a fluid model, introduce source terms in a plasma drift-fluid model due to inelastic collisions. The resulting source terms are included in a four-field drift-fluid model, and it is shown how an increasing neutral particle density in the edge and SOL regions influences the plasma particle transport across the last-closed-flux-surface. It is found that an appropriate gas puffing rate allows for the edge density in the simulation to be self-consistently maintained due to ionization of neutrals in the confined region.

Effects of fusion relevant transient energetic radiation, plasma and thermal load on PLANSEE double forged tungsten samples in a low-energy plasma focus device

Science.gov (United States)

Javadi, S.; Ouyang, B.; Zhang, Z.; Ghoranneviss, M.; Salar Elahi, A.; Rawat, R. S.

2018-06-01

Tungsten is the leading candidate for plasma facing component (PFC) material for thermonuclear fusion reactors and various efforts are ongoing to evaluate its performance or response to intense fusion relevant radiation, plasma and thermal loads. This paper investigates the effects of hot dense decaying pinch plasma, highly energetic deuterium ions and fusion neutrons generated in a low-energy (3.0 kJ) plasma focus device on the structure, morphology and hardness of the PLANSEE double forged tungsten (W) samples surfaces. The tungsten samples were provided by Forschungszentrum Juelich (FZJ), Germany via International Atomic Energy Agency, Vienna, Austria. Tungsten samples were irradiated using different number of plasma focus (PF) shots (1, 5 and 10) at a fixed axial distance of 5 cm from the anode top and also at various distances from the top of the anode (5, 7, 9 and 11 cm) using fixed number (5) of plasma focus shots. The virgin tungsten sample had bcc structure (α-W phase). After PF irradiation, the XRD analysis showed (i) the presence of low intensity new diffraction peak corresponding to β-W phase at (211) crystalline plane indicating the partial structural phase transition in some of the samples, (ii) partial amorphization, and (iii) vacancy defects formation and compressive stress in irradiated tungsten samples. Field emission scanning electron microscopy showed the distinctive changes to non-uniform surface with nanometer sized particles and particle agglomerates along with large surface cracks at higher number of irradiation shots. X-ray photoelectron spectroscopy analysis demonstrated the reduction in relative tungsten oxide content and the increase in metallic tungsten after irradiation. Hardness of irradiated samples initially increased for one shot exposure due to reduction in tungsten oxide phase, but then decreased with increasing number of shots due to increasing concentration of defects. It is demonstrated that the plasma focus device provides

An in situ accelerator-based diagnostic for plasma-material interactions science on magnetic fusion devices.

Science.gov (United States)

Hartwig, Zachary S; Barnard, Harold S; Lanza, Richard C; Sorbom, Brandon N; Stahle, Peter W; Whyte, Dennis G

2013-12-01

This paper presents a novel particle accelerator-based diagnostic that nondestructively measures the evolution of material surface compositions inside magnetic fusion devices. The diagnostic's purpose is to contribute to an integrated understanding of plasma-material interactions in magnetic fusion, which is severely hindered by a dearth of in situ material surface diagnosis. The diagnostic aims to remotely generate isotopic concentration maps on a plasma shot-to-shot timescale that cover a large fraction of the plasma-facing surface inside of a magnetic fusion device without the need for vacuum breaks or physical access to the material surfaces. Our instrument uses a compact (~1 m), high-current (~1 milliamp) radio-frequency quadrupole accelerator to inject 0.9 MeV deuterons into the Alcator C-Mod tokamak at MIT. We control the tokamak magnetic fields--in between plasma shots--to steer the deuterons to material surfaces where the deuterons cause high-Q nuclear reactions with low-Z isotopes ~5 μm into the material. The induced neutrons and gamma rays are measured with scintillation detectors; energy spectra analysis provides quantitative reconstruction of surface compositions. An overview of the diagnostic technique, known as accelerator-based in situ materials surveillance (AIMS), and the first AIMS diagnostic on the Alcator C-Mod tokamak is given. Experimental validation is shown to demonstrate that an optimized deuteron beam is injected into the tokamak, that low-Z isotopes such as deuterium and boron can be quantified on the material surfaces, and that magnetic steering provides access to different measurement locations. The first AIMS analysis, which measures the relative change in deuterium at a single surface location at the end of the Alcator C-Mod FY2012 plasma campaign, is also presented.

Interaction of powerful hot plasma and fast ion streams with materials in dense plasma focus devices

Energy Technology Data Exchange (ETDEWEB)

Chernyshova, M., E-mail: maryna.chernyshova@ipplm.pl [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Gribkov, V.A. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Institution of Russian Academy of Sciences A.A. Baikov Institute of Metallurgy and Material Science RAS, Moscow (Russian Federation); Kowalska-Strzeciwilk, E.; Kubkowska, M.; Miklaszewski, R.; Paduch, M.; Pisarczyk, T.; Zielinska, E. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Demina, E.V.; Pimenov, V.N.; Maslyaev, S.A. [Institution of Russian Academy of Sciences A.A. Baikov Institute of Metallurgy and Material Science RAS, Moscow (Russian Federation); Bondarenko, G.G. [National Research University Higher School of Economics (HSE), Moscow (Russian Federation); Vilemova, M.; Matejicek, J. [Institute of Plasma Physics of the CAS, Prague (Czech Republic)

2016-12-15

Highlights: • Materials perspective for use in mainstream nuclear fusion facilities were studied. • Powerful streams of hot plasma and fast ions were used to induce irradiation. • High temporal, spatial, angular and spectral resolution available in experiments. • Results of irradiation were investigated by number of analysis techniques. - Abstract: A process of irradiating and ablating solid-state targets with hot plasma and fast ion streams in two Dense Plasma Focus (DPF) devices – PF-6 and PF-1000 was examined by applying a number of diagnostics of nanosecond time resolution. Materials perspective for use in chambers of the mainstream nuclear fusion facilities (mainly with inertial plasma confinement like NIF and Z-machine), intended both for the first wall and for constructions, have been irradiated in these simulators. Optical microscopy, SEM, Atomic Emission Spectroscopy, images in secondary electrons and in characteristic X-ray luminescence of different elements, and X-ray elemental analysis, gave results on damageability for a number of materials including low-activated ferritic and austenitic stainless steels, β-alloy of Ti, as well as two types of W and a composite on its base. With an increase of the number of shots irradiating the surface, its morphology changes from weakly pronounced wave-like structures or ridges to strongly developed ones. At later stages, due to the action of the secondary plasma produced near the target materials they melted, yielding both blisters and a fracturing pattern: first along the grain and then “in-between” the grains creating an intergranular net of microcracks. At the highest values of power flux densities multiple bubbles appeared. Furthermore, in this last case the cracks were developed because of microstresses at the solidification of melt. Presence of deuterium within the irradiated ferritic steel surface nanolayers is explained by capture of deuterons in lattice defects of the types of impurity atoms

Modelling ion cyclotron emission from KSTAR tokamak and LHD helical device plasmas

Science.gov (United States)

Dendy, Richard; Chapman, Ben; Reman, Bernard; Chapman, Sandra; Akiyama, Tsuyoshi; Yun, Gunsu

2017-10-01

New high quality measurements of ion cyclotron emission (ICE) from KSTAR and LHD greatly extend the scope and diversity of plasma conditions under which ICE is observed. Variables include the origin (fusion reactions or neutral beam injection) and energy (sub- or super-Alfvénic) of the minority energetic ions that drive ICE; the composition of the bulk plasma (hydrogen or deuterium) which supports the modes excited; plasma density in the emitting region, and the timescale on which it changes; and toroidal magnetic field geometry (tokamak or helical device). Future exploitation of ICE as a diagnostic for energetic ion populations in JET D-T plasmas and in ITER rests on quantitative understanding of the physics of the emission. This is tested and extended by current KSTAR and LHD measurements of ICE. We report progress on direct numerical simulation using full orbit ion kinetic codes that solve the Maxwell-Lorentz equations for hundreds of millions of particles. In the saturated regime, these simulations yield excited field spectra that correspond directly to the measured ICE spectra under diverse KSTAR and LHD regimes. At early times, comparison of simulation outputs with linear analytical theory confirms the magnetoacoustic cyclotron instability as the basic driver of ICE. Supported by RCUK Energy Programme Grant EP/P012450/1, NRF Korea Grant 2014M1A7A1A03029881, NIFS budget ULHH029 and Euratom.

Development of a double plasma gun device for investigation of effects of vapor shielding on erosion of PFC materials under ELM-like pulsed plasma bombardment

Science.gov (United States)

Sakuma, I.; Iwamoto, D.; Kitagawa, Y.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2012-10-01

It is considered that thermal transient events such as type I edge localized modes (ELMs) could limit the lifetime of plasma-facing components (PFCs) in ITER. We have investigated surface damage of tungsten (W) materials under transient heat and particle loads by using a magnetized coaxial plasma gun (MCPG) device at University of Hyogo. The capacitor bank energy for the plasma discharge is 144 kJ (2.88 mF, 10 kVmax). Surface melting of a W material was clearly observed at the energy density of ˜2 MJ/m2. It is known that surface melting and evaporation during a transient heat load could generate a vapor cloud layer in front of the target material [1]. Then, the subsequent erosion could be reduced by the vapor shielding effect. In this study, we introduce a new experiment using two MCPG devices (MCPG-1, 2) to understand vapor shielding effects of a W surface under ELM-like pulsed plasma bombardment. The capacitor bank energy of MCPG-2 is almost same as that of MCPG-1. The second plasmoid is applied with a variable delay time after the plasmoid produced by MCPG-1. Then, a vapor cloud layer could shield the second plasma load. To verify the vapor shielding effects, surface damage of a W material is investigated by changing the delay time. In the conference, the preliminary experimental results will be shown.[4pt] [1] A. Hassanein et al., J. Nucl. Mater. 390-391, pp. 777-780 (2009).

Removal of Microbial Contamination from Surface by Plasma

Science.gov (United States)

Feng, Xinxin; Liu, Hongxia; Shen, Zhenxing; Wang, Taobo

2018-01-01

Microbial contamination is closely associated with human and environmental health, they can be tested on food surfaces, medical devices, packing material and so on. In this paper the removal of the microbial contamination from surface using plasma treatment is investigated. The Escherichia coli (E. coli) has been chosen as a bio-indicator enabling to evaluate the effect of plasma assisted microbial inactivation. Oxygen gas was as the working gas. The plasma RF power, plasma exposition time, gas flow and the concentration of organic pollutant were varied in order to see the effect of the plasma treatment on the Gram-negative germ removal. After the treatment, the microbial abatement was evaluated by the standard plate count method. This proved a positive effect of the plasma treatment on Gram-negative germ removal. The kinetics and mathematical model of removal were studied after plasma treatment, and then the removing course of E. coli was analyzed. This work is meaningful for deepening our understanding of the fundamental scientific principles regarding microbial contamination from surface by plasma.

Bridge between fusion plasma and plasma processing

International Nuclear Information System (INIS)

Ohno, Noriyasu; Takamura, Shuichi

2008-01-01

In the present review, relationship between fusion plasma and processing plasma is discussed. From boundary-plasma studies in fusion devices new applications such as high-density plasma sources, erosion of graphite in a hydrogen plasma, formation of helium bubbles in high-melting-point metals and the use of toroidal plasmas for plasma processing are emerging. The authors would like to discuss a possibility of knowledge transfer from fusion plasmas to processing plasmas. (T. Ikehata)

Effects of admixture gas on the production of {sup 18}F radioisotope in plasma focus devices

Energy Technology Data Exchange (ETDEWEB)

Talaei, Ahmad [Nuclear Science and Technology Research Institute (NSTR), Nuclear Science Research School, A.E.O.I., 14155-1339 Tehran (Iran, Islamic Republic of); Sadat Kiai, S.M., E-mail: sadatkiai@yahoo.co [Nuclear Science and Technology Research Institute (NSTR), Nuclear Science Research School, A.E.O.I., 14155-1339 Tehran (Iran, Islamic Republic of); Zaeem, A.A. [Department of Physics, Khaje Nasir University of Technology (K.N. Toosi), 1541846911 Tehran (Iran, Islamic Republic of)

2010-12-15

In this article, the effect of admixture gas on the heating and cooling of pinched plasma directly related to the enhancement or reduction of {sup 18}F production through the {sup 16}O({sup 3}He, p){sup 18}F is considered in the plasma focus devices. It is shown that by controlling the velocity of added Oxygen particles mixed with the working helium gas into the plasma focus chamber, one can increase the current and decrease the confinement time (plasma heating) or vice verse (plasma cooling). The highest level of nuclear activities of {sup 18}F was found around 16% of the Oxygen admixture participation and was about 0.35 MBq in the conditions of 20 kJ, 0.1 Hz and after 2 min operating of Dena PF. However, in the same condition, but for the frequency of 1 Hz, the level of activity increased up to 3.4 MBq.

Calculation of transport coefficients in an axisymmetric plasma

International Nuclear Information System (INIS)

Shumaker, D.E.

1977-01-01

A method of calculating the transport coefficient in an axisymmetric toroidal plasma is presented. This method is useful in calculating the transport coefficients in a Tokamak plasma confinement device. The particle density and temperature are shown to be a constant on a magnetic flux surface. Transport equations are given for the total particle flux and total energy flux crossing a closed toroidal surface. Also transport equations are given for the toroidal magnetic flux. A computer code was written to calculate the transport coefficients for a three species plasma, electrons and two species of ions. This is useful for calculating the transport coefficients of a plasma which contains impurities. It was found that the particle and energy transport coefficients are increased by a large amount, and the transport coefficients for the toroidal magnetic field are reduced by a small amount

Growth, structural and plasma illumination properties of nanocrystalline diamond-decorated graphene nanoflakes

OpenAIRE

Kamatchi Jothiramalingam, Sankaran; Chang, Ting Hsun; Bikkarolla, Santosh Kumar; Roy, Susanta Sinha; Papakonstantinou, Pagona; Drijkoningen, Sien; Pobedinskas, Paulius; Van Bael, Marlies K.; Tai, Nyan-Hwa; Lin, I. -Nan; Haenen, Ken

2016-01-01

The improvement of the plasma illumination (PI) properties of a microplasma device due to the application of nanocrystalline diamond-decorated graphene nanoflakes (NCD-GNFs) as a cathode is investigated. The improved plasma illumination (PI) behavior is closely related to the enhanced field electron emission (FEE) properties of the NCD-GNFs. The NCD-GNFs possess better FEE characteristics with a low turn-on field of 9.36 V mu m(-1) to induce the field emission, a high FEE current density of 2...

Studies of the Hard X-ray Emission from the Filippov Type Plasma Focus Device, Dena

Science.gov (United States)

Tafreshi, M. A.; Saeedzadeh, E.

2006-12-01

This article is about the characteristics of the hard X-ray (HXR) emission from the Filippov type plasma focus (PF) device, Dena. The article begins with a brief presentation of Dena, and the mechanism of the HXR production in PF devices. Then using the differential absorption spectrometry, the energy resolved spectrum of the HXR emission from a 37 kJ discharge in Dena, is estimated. The energy flux density and the energy fluence of this emission have also been calculated to be 1.9 kJ cm-2 s-1 and 9.4 × 10-5 J cm-2. In the end, after presentation of radiography of sheep bones and calf ribs, the medical application of the PF devices has been discussed.

Characterization of bismuth nanospheres deposited by plasma focus device

Energy Technology Data Exchange (ETDEWEB)

Ahmad, M., E-mail: cscientific2@aec.org.sy [IBA Laboratory, Chemistry Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus (Syrian Arab Republic); Al-Hawat, Sh.; Akel, M. [Physics Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus (Syrian Arab Republic); Mrad, O. [Chemistry Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus (Syrian Arab Republic)

2015-02-14

A new method for producing thin layer of bismuth nanospheres based on the use of low energy plasma focus device is demonstrated. Various techniques such as scanning electron microscopy, Rutherford backscattering spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy have been used to characterize the morphology and the composition of the nanospheres. Experimental parameters may be adjusted to favour the formation of bismuth nanospheres instead of microspheres. Therefore, the formation of large surface of homogeneous layer of bismuth nanospheres with sizes of below 100 nm can be obtained. The natural snowball phenomenon is observed to be reproduced in nanoscale where spheres roll over the small nanospheres and grow up to bigger sizes that can reach micro dimensions. The comet-like structure, a reverse phenomenon to snowball is also observed.

Characterization of bismuth nanospheres deposited by plasma focus device

International Nuclear Information System (INIS)

Ahmad, M.; Al-Hawat, Sh.; Akel, M.; Mrad, O.

2015-01-01

A new method for producing thin layer of bismuth nanospheres based on the use of low energy plasma focus device is demonstrated. Various techniques such as scanning electron microscopy, Rutherford backscattering spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy have been used to characterize the morphology and the composition of the nanospheres. Experimental parameters may be adjusted to favour the formation of bismuth nanospheres instead of microspheres. Therefore, the formation of large surface of homogeneous layer of bismuth nanospheres with sizes of below 100 nm can be obtained. The natural snowball phenomenon is observed to be reproduced in nanoscale where spheres roll over the small nanospheres and grow up to bigger sizes that can reach micro dimensions. The comet-like structure, a reverse phenomenon to snowball is also observed

Data on rotating plasma operation in Tornado traps

International Nuclear Information System (INIS)

Lehnert, B.

1977-01-01

Rotating plasma operation in spiral coil 'Tornado' traps provides a unique combination of confinement and heating properties. Such a system consists of a closed and compact magnetic bottle to which the crossed-field technique can be applied, in absence of end insulators and their critical velocity limitation effect. This is expected to lead to the generation and heating of fully ionized plasmas within a large range of ion densities, temperatures, and rotational velocities. Provided that stable operation becomes possible at high temperatures and the effects due to the asymmetries of the spiral coil structure can be neglected, it is likely that Tornado traps can be used as strong neutron sources of moderately large dimensions and technically realizable parameter values. Some detailed data and operation ranges are outlined for the 'Tornado 650' device in Leningrad, and for a somewhat larger device which may be operated as a neutron source. (Auth.)

On the scaling of magnetic plasma confinement under classical conditions

International Nuclear Information System (INIS)

Lehnert, B.

1979-04-01

Present magnetic confinement schemes based on tokamaks and similar devices are characterized by relatively large losses and low beta values. As a consequence, thermonuclear conditions can only be reached in such devices at large linear dimensions or by means of very strong magnetic fields, in combination with large heating powers. This does not rule out the possibility of realizing the same conditions on a smaller scale, i.e. by finding alternative schemes which provide classical and stable confinement of a pure plasma in a closed magnetic bottle. (author)

Plasma position control device for thermonuclear device

Energy Technology Data Exchange (ETDEWEB)

Onozuka, Masanori [Mitsubishi Heavy Industries Ltd., Tokyo (Japan); Fujita, Jun-ya; Ioki, Kimihiro

1995-10-03

The present invention concerns plasma position control coils having a feeder line structure not requiring high strength for the support portion. Namely, the coils are formed by twisting feeder lines extended from plasma position control coils in a vacuum vessel. The twisted feeder lines are supported using an appropriate structural member. Electromagnetic load is generated to the feeder lines being extended from the position control coils and traversing toroidal fields at a current introduction lines and at current delivery lines respectively. However, since the feeder lines have substantially spiral shape consisting of two twisted lines, the electromagnetic load and the moment caused by the generated load which are inversed to each other are off set. Accordingly, only extremely small force is exerted on the fittings which support the feeder lines. Therefore, small strength may suffice for the fittings and the gaps of mounting the fittings may be made longer. (I.S.).

Plasma position control device for thermonuclear device

International Nuclear Information System (INIS)

Onozuka, Masanori; Fujita, Jun-ya; Ioki, Kimihiro.

1995-01-01

The present invention concerns plasma position control coils having a feeder line structure not requiring high strength for the support portion. Namely, the coils are formed by twisting feeder lines extended from plasma position control coils in a vacuum vessel. The twisted feeder lines are supported using an appropriate structural member. Electromagnetic load is generated to the feeder lines being extended from the position control coils and traversing toroidal fields at a current introduction lines and at current delivery lines respectively. However, since the feeder lines have substantially spiral shape consisting of two twisted lines, the electromagnetic load and the moment caused by the generated load which are inversed to each other are off set. Accordingly, only extremely small force is exerted on the fittings which support the feeder lines. Therefore, small strength may suffice for the fittings and the gaps of mounting the fittings may be made longer. (I.S.)

Equilibrium and stability studies for high beta plasmas in torsatron/heliotron devices

International Nuclear Information System (INIS)

Carreras, B.A.; Cooper, W.A.; Charlton, L.A.

1983-01-01

The equilibrium and stability properties of high β plasmas in torsatron/heliotron devices have been investigated. Three numerical approaches have been used to study plasma equilibria for a range of coil configurations. The method of averaging permits fast equilibrium and stability calculations. Two fully 3-D codes, namely the Chodura-Schluter code, and the NEAR code recently developed at ORNL, are used to explore selected regions of parameter space. The resulting equilibria calculated with different methods are in good agreement. This validates the average method approach and enhances its usefulness. Results are presented for configurations with different aspect ratios and number of field periods. The role of the vertical field has also been studied in detail. The main conclusion is that for moderate aspect ratios (Asub(p) <= 8), the self-stabilizing effect of the magnetic axis shift is large enough to open a direct path to the second stability regime. (author)

Closed form analytic solutions describing glow discharge plasma

International Nuclear Information System (INIS)

Pai, S.T.; Guo, X.M.; Zhou, T.D.

1996-01-01

On the basis of an analytic model developed previously [S. T. Pai, J. Appl. Phys. 71, 5820 (1992)], an improved version of the model for the description of dc glow discharge plasma was successfully developed. A set of closed form solutions was obtained from the governing equations. The two-dimensional, analytic solutions are functional and completely satisfy the governing equations, the actual boundary conditions, and Maxwell equations. They can be readily used to carry out numerical calculations without the necessity of employing any assumed boundary conditions. Results obtained from the model reveal that as the discharge gap spacing or pressure increases the maximum value in the electron density distribution moves toward the cathode. At a sufficiently large value of gap spacing, the positive column phenomenon begins to appear in the discharge region. The model has the capability of treating the positive column and negative glow as a continuous system without the necessity of studying them separately. The model also predicts a sharp rise of the positive ion density near the cathode and field reversal in the anode region. Variation of the electrode radius produces little effect on the axial spatial distribution of physical quantities studied. copyright 1996 American Institute of Physics

Investigation of MHD Instabilities in Jets and Bubbles Using a Compact Coaxial Plasma Gun in a Background Magnetized Plasma

Science.gov (United States)

Zhang, Y.; Fisher, D. M.; Wallace, B.; Gilmore, M.; Hsu, S. C.

2016-10-01

A compact coaxial plasma gun is employed for experimental investigation of launching plasma into a lower density background magnetized plasma. Experiments are being conducted in the linear device HelCat at UNM. Four distinct operational regimes with qualitatively different dynamics are identified by fast CCD camera images. For regime I plasma jet formation, a global helical magnetic configuration is determined by a B-dot probe array data. Also the m =1 kink instability is observed and verified. Furthermore, when the jet is propagating into background magnetic field, a longer length and lifetime jet is formed. Axial shear flow caused by the background magnetic tension force contributes to the increased stability of the jet body. In regime II, a spheromak-like plasma bubble formation is identified when the gun plasma is injected into vacuum. In contrast, when the bubble propagates into a background magnetic field, the closed magnetic field configuration does not hold anymore and a lateral side, Reilgh-Taylor instability develops. Detailed experimental data and analysis will be presented for these cases.

To a question on thermal protection of constructional elements of vacuum-plasma devices

International Nuclear Information System (INIS)

Borisko, V.N.; Borisko, S.V.; Zinovev, D.V.; Lapshin, V.I.; Tselujko, A.F.

2005-01-01

The progress in development of vacuum-plasma devices is connected with the design and creation of constructional elements from materials, which have a high erosion resistance and can maintain the large specific flux of energy per effective area. Recently as the materials of such constructional elements it was offered to use the reversible sorbents of hydrogen of Zr-V system, which have high-rates of sorption-desorption and large thermal effect of the hydride phases decomposition. In the paper an experimental research of the thermal conditions features of the metal-hydride electrodes, which subjected of the energy loads in the vacuum-plasma devices, are given. The simulation of the energy loads on the electrodes was carried out with the help of gas discharge plasma as there is an possibility to vary the energy spectrum of the bombarding particles and to gather a necessary radiation dose to the material surface. For comparative examinations of various materials under the irradiation by high-energy heavy particles it is the most convenient to use the Penning discharge. In this case, the cathodes made of different materials are under the identical conditions even at the change of working discharge modes. Therefore in the device on the basis of the Penning discharge the cathodes of metal-hydride and stainless steel were set. It was detected, that the increase of the temperature gradient of metal-hydride cathode goes down with the increase of discharge current value. The dependence of operating temperatures difference of cathodes from exposure time has shown that the temperature of the metal-hydride cathode is sufficiently lower than the temperature of the stainless steel cathode. Such a softening of the thermal operation conditions of the metal hydride cathode is caused by thermal decomposition of hydride phases. Besides there is the energy flow dissipation of bombarding particles on the protective gas target formed by desorbed hydrogen. The considerable decrease of

The current-voltage characteristic and potential oscillations of a double layer in a triple plasma device

International Nuclear Information System (INIS)

Carpenter, R.T.; Torven, S.

1986-07-01

The properties of a strong double layer in a current circuit with a capacitance and an inductance are investigated in a triple plasma device. The double layer gives rise to a region of negative differential resistance in the current-voltage characteristic of the device, and this gives non-linear oscillations in the current and the potential drop over the double layer (PhiDL). For a sufficiently large circuit inductance PhiDL reaches an amplitude given by the induced voltage (-LdI/dt) which is much larger than the circuit EMF due to the rapid current decrease when PhiDL increases. A variable potential minimum exists in the plasma on the low potential side of the double layer, and the depth of the minimum increases when PhiDL increases. An increasing fraction of the electrons incident at the double layer are then reflected, and this is found to be the main process giving rise to the negative differential resistance. A qualitative model for the variation of the minimum potential with PhiDL is also proposed. It is based on the condition that the minimum potential must adjust itself self-consistentely so that quasi-neutrality is maintained in the plasma region where the minimum is assumed. (authors)

Lightweight Portable Plasma Medical Device - Plasma Engineering Research Laboratory

Science.gov (United States)

2014-10-01

by Remote Exposure of Resistive Barrier Cold Plasma." Biotechnology and Bioengineering, vol. 111, No. 3. p. 565 - 574 (2014). 16. Magesh...remote exposure of resistive barrier cold plasma.” Biotechnology and Bioengineering. (Accepted for publication in the next issue in 2013) 11. Magesh...foes-Safety-and-Security--1945) 4. “University Touts ’Superbug’ Killing Technology”, Quality Assurance and Food Safety Magazine , July 2013. (Link

Behaviour and design considerations for continuous flow closed-open-closed liquid microchannels.

Science.gov (United States)

Melin, Jessica; van der Wijngaart, Wouter; Stemme, Göran

2005-06-01

This paper introduces a method of combining open and closed microchannels in a single component in a novel way which couples the benefits of both open and closed microfluidic systems and introduces interesting on-chip microfluidic behaviour. Fluid behaviour in such a component, based on continuous pressure driven flow and surface tension, is discussed in terms of cross sectional flow behaviour, robustness, flow-pressure performance, and its application to microfluidic interfacing. The closed-open-closed microchannel possesses the versatility of upstream and downstream closed microfluidics along with open fluidic direct access. The device has the advantage of eliminating gas bubbles present upstream when these enter the open channel section. The unique behaviour of this device opens the door to applications including direct liquid sample interfacing without the need for additional and bulky sample tubing.

A continuous flow micro filtration device for plasma/blood separation using submicron vertical pillar gap structures

International Nuclear Information System (INIS)

Kang, Tae Goo; Ji, Hongmiao; Lim, Pei Yi; Chen, Yu; Yoon, Yong-Jin

2014-01-01

This work demonstrates a continuous flow plasma/blood separator using a vertical submicron pillar gap structure. The working principle of the proposed separator is based on size exclusion of cells through cross-flow filtration, in which only plasma is allowed to pass through submicron vertical pillars located tangential to the main flow path of the blood sample. The maximum filtration efficiency of 99.9% was recorded with a plasma collection rate of 0.67 µl min −1 for an input blood flow rate of 12.5 µl min −1 . The hemolysis phenomenon was observed for an input blood flow rate above 30 µl min −1 . Based on the experimental results, we can conclude that the proposed device shows potential for the application of on-chip plasma/blood separation as a part of integrated point-of-care (POC) diagnostics systems. (technical note)

Numerical simulation of current-free double layers created in a helicon plasma device

Science.gov (United States)

Rao, Sathyanarayan; Singh, Nagendra

2012-09-01

Two-dimensional simulations reveal that when radially confined source plasma with magnetized electrons and unmagnetized ions expands into diverging magnetic field B, a current-free double layer (CFDL) embedded in a conical density structure forms, as experimentally measured in the Australian helicon plasma device (HPD). The magnetized electrons follow the diverging B while the unmagnetized ions tend to flow directly downstream of the source, resulting in a radial electric field (E⊥) structure, which couples the ion and electron flows. Ions are transversely (radially) accelerated by E⊥ on the high potential side of the double layer in the CFDL. The accelerated ions are trapped near the conical surface, where E⊥ reverses direction. The potential structure of the CFDL is U-shaped and the plasma density is enhanced on the conical surface. The plasma density is severely depleted downstream of the parallel potential drop (φ||o) in the CFDL; the density depletion and the potential drop are related by quasi-neutrality condition, including the divergence in the magnetic field and in the plasma flow in the conical structure. The potential and density structures, the CFDL spatial size, its electric field strengths and the electron and ion velocities and energy distributions in the CFDL are found to be in good agreements with those measured in the Australian experiment. The applicability of our results to measured axial potential profiles in magnetic nozzle experiments in HPDs is discussed.

Studies on divertor effects by means of the Doublet-III high-temperature plasma device

International Nuclear Information System (INIS)

Shimada, Michiya

1982-12-01

The diverter action on impurity removal, helium ash compression and radiative cooling was studied in Doublet-3, placing emphasis on the applicability to reacting plasma grade devices such as Intor. The following principal results were obtained with a single-null poloidal diverter without the diverter chamber and the diverter throat (referred to as ''open diverter''), and the diverter coils being installed outside the vacuum chamber. The diverter reduced metallic impurities in the central plasma volume, carbon influx and radiation loss, and changed a typically peaked radiation power profile to a hollow profile. In helium-seeded diverter discharge, helium gas pressure near the diverter rose with the increase of main plasma density, and the pressure was high enough to demonstrate the possibility of helium ash exhaust in a diverted tokamak. The radiation power in the diverter volume significantly increased with the increasing main plasma density to as much as 50 % of the input ohmic power. The remote radiation cooling reduced the thermal load on the diverter plate, and the electron temperature near the diverter plate was cooled down. The source of this remote radiative cooling power was the mixture of line radiation of hydrogen neutral and oxygen. (Kako, I.)

Stability of expanded plasma focus

International Nuclear Information System (INIS)

Soliman, H.M.

1994-01-01

In this study, the stabilization of the expanded plasma focus formed by 4.5 kJ plasma focus device of Mather type by magnetic field is presented. The experimental results of the induced axial magnetic field and electric probe measurements of the expanded plasma focus show that, the plasma consists of three plasmoids, electron temperature measurements off the plasmoids at a point close to the muzzle are 26 eV, 30 eV and 27 eV respectively and the electron densities are 6.6 x 10 14 , 6.1 x 10 14 / cm 3 respectively. The presence of external axial magnetic field (B 2 = 1.6 kg) at the mid distance between the breech and the muzzle has a less effect on the stability of expanded focus and it causes a restriction for the plasma motion. the electron temperature of the three plasmoids are found to increase in that case by 23%, 18.5% respectively. When this axial magnetic field is applied at the muzzle end, it leads to a more stable expanded plasma focus which consists mainly of one plasmoid with electron temperature of 39 eV and density of 3.4 x 10 14 / cm 3 . 5 figs

Gas supply device

International Nuclear Information System (INIS)

Yamamoto, Tokihiro.

1986-01-01

Purpose: When injecting gas during plasma discharge, to prevent erronous operation of the piezoelectric valves due to vibrations and to inject gas into the vacuum vessel by accurately controlling gas flow. Constitution: The piezoelectric valve designed to control the flow of gas when charging vacuum vessels is installed between the vacuum vessel and the gas cylinder and a pulse voltage generator to control the valve (open/close) and the reverse voltage generator to apply a reverse current to the valve element are also provided. When a voltage is applied to the piezoelectric element, the piezoelectric element bends. However, when the polarity is changed, the direction of the bend is also reversed. The seat portion is pressed in proportion to the degree of bending. When gas is injected while plasma is being discharged, the gap created, due to vibrations, between the piezoelectric element and the sealing material is prevented by the application of a reverse current. This allows precise control of the gas injection volume as well as the injection interval. This assures maintenance of precise test conditions when testing thermonuclear devices. (Horiuchi, T.)

The application of Cold Atmospheric Plasma (CAP) for the sterilisation of spacecraft materials

Science.gov (United States)

Rettberg, Petra; Barczyk, Simon; Morfill, Gregor; Thomas, Hubertus; Satoshi Shimizu, .; Shimizu, Tetsuji; Klaempfl, Tobias

2012-07-01

Plasma, oft called the fourth state of matter after solid, liquid and gas, is defined by its ionized state. Ionization can be induced by different means, such as a strong electromagnetic field applied with a microwave generator. The concentration and composition of reactive atoms and molecules produced in Cold Atmospheric Plasma (CAP) depends on the gases used, the gas flow, the power applied, the humidity level etc.. In medicine, low-temperature plasma is already used for the sterilization of surgical instruments, implants and packaging materials as plasma works at the atomic level and is able to reach all surfaces, even the interior of small hollow items like needles. Its ability to sterilise is due to the generation of biologically active bactericidal agents, such as free radicals and UV radiation. In the project PLASMA-DECON (DLR/BMWi support code 50JR1005) a prototype of a device for sterilising spacecraft material and components was built based on the surface micro-discharge (SMD) plasma technology. The produced plasma species are directed into a closed chamber which contains the parts that need to be sterilised. To test the inactivation efficiency of this new device bacterial spores were used as model organisms because in the COSPAR Planetary Protection Policy all bioburden constraints are defined with respect to the number of spores (and other heat-tolerant aerobic microorganisms). Spores from different Bacillus species and strains, i.e. wildtype strains from culture collections and isolates from spacecraft assembly cleanrooms, were dried on three different spacecraft relevant materials and exposed to CAP. The specificity, linearity, precision, and effective range of the device was investigated. From the results obtained it can be concluded that the application of CAP proved to be a suitable method for bioburden reduction / sterilisation in the frame of planetary protection measures and the design of a larger plasma device is planned in the future.

Development of net-current free heliotron plasmas in the Large Helical Device

International Nuclear Information System (INIS)

Komori, A.; Yamada, H.; Kaneko, O.; Kawahata, K.; Mutoh, T.; Ohyabu, N.; Imagawa, S.; Ida, K.; Nagayama, Y.; Shimozuma, T.; Watanabe, K.Y.; Mito, T.; Kobayashi, M.; Nagaoka, K.; Sakamoto, R.; Ohdachi, S.; Sakakibara, S.; Ashikawa, N.; Igami, H.; Kasahara, H.; Kubo, S.; Kumazawa, R.; Nishiura, M.; Masuzaki, S.; Tanaka, K.; Toi, K.; Yoshinuma, M.; Narushima, Y.; Tamura, N.; Saito, K.; Seki, T.; Sudo, S.; Tanaka, H.; Tokuzawa, T.; Yanagi, N.; Yokoyama, M.; Yoshimura, Y.; Akiyama, T.; Chikaraishi, H.; Emoto, M.; Funaba, H.; Goncharov, P.; Goto, M.; Ichiguchi, K.; Ido, T.; Ikeda, K.; Yoshida, N.; Inagaki, S.; Idei, H.; Feng, Y.; Weller, A.; Fukuda, T.; Mitarai, O.; Murakami, S.; Nakamura, Y.; Hino, T.; Ohno, N.; Okamura, T.; Iio, S.; Chowdhuri, M.; Ezumi, N.; Garcia, L.; Ichimura, M.; Irie, M.; Isayama, Akihiko; Iwamae, Atsushi; Takenaga, Hidenobu; Urano, Hajime

2008-10-01

Remarkable progress in the physical parameters of net-current free plasmas has been made in the Large Helical Device (LHD) since the last Fusion Energy Conference in Chengdu, 2006 (O. Motojima et al., Nucl. Fusion 47 (2007) S668). The beta value reached 5 % and a high beta state beyond 4.5% from the diamagnetic measurement has been maintained for longer than 100 times the energy confinement time. The density and temperature regimes also have been extended. The central density has exceeded 1.0x10 21 m -3 due to the formation of an Internal Diffusion Barrier (IDB). The ion temperature has reached 6.8 keV at the density of 2x10 19 m -3 , which is associated with the suppression of ion heat conduction loss. Although these parameters have been obtained in separated discharges, each fusion-reactor relevant parameter has elucidated the potential of net-current free heliotron plasmas. Diversified studies in recent LHD experiments are reviewed in this paper. (author)

Equilibrium and stability studies for high-beta plasmas in torsatron/heliotron devices

International Nuclear Information System (INIS)

Carreras, B.A.; Charlton, L.A.; Cooper, W.A.

1983-01-01

The equilibrium and stability properties of high-#betta# plasmas in torsatron/heliotron devices have been investigated. Three numerical approaches have been used to study plasma equilibria for a range of coil configurations. The method of averaging permits fast equilibrium and stability calculations. Two fully 3-D codes, namely the Chodura-Schluter code, and the NEAR code recently developed at ORNL, are used to explore selected regions of parameter space. The resulting equilibria calculated with different methods are in good agreement. This validates the average method approach and enhances its usefulness. Results are presented for configurations with different aspect ratios and number of field periods. The role of the vertical field has also been studied in detail. The main conclusion is that for moderate aspect ratios (A/sub p/ less than or equal to 8), the self-stabilizing effect of the magnetic-axis shift is large enough to open a direct path to the second-stability regime

Laser-driven, magnetized quasi-perpendicular collisionless shocks on the Large Plasma Device

International Nuclear Information System (INIS)

Schaeffer, D. B.; Everson, E. T.; Bondarenko, A. S.; Clark, S. E.; Constantin, C. G.; Vincena, S.; Van Compernolle, B.; Tripathi, S. K. P.; Gekelman, W.; Niemann, C.; Winske, D.

2014-01-01

The interaction of a laser-driven super-Alfvénic magnetic piston with a large, preformed magnetized ambient plasma has been studied by utilizing a unique experimental platform that couples the Raptor kJ-class laser system [Niemann et al., J. Instrum. 7, P03010 (2012)] to the Large Plasma Device [Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)] at the University of California, Los Angeles. This platform provides experimental conditions of relevance to space and astrophysical magnetic collisionless shocks and, in particular, allows a detailed study of the microphysics of shock formation, including piston-ambient ion collisionless coupling. An overview of the platform and its capabilities is given, and recent experimental results on the coupling of energy between piston and ambient ions and the formation of collisionless shocks are presented and compared to theoretical and computational work. In particular, a magnetosonic pulse consistent with a low-Mach number collisionless shock is observed in a quasi-perpendicular geometry in both experiments and simulations

New Mixed Conductivity Mechanisms in the Cold Plasma Device Based on Silver-Modified Zeolite Microporous Electronic Materials

Science.gov (United States)

Koç, Sevgul Ozturk; Galioglu, Sezin; Ozturk, Seckin; Kurç, Burcu Akata; Koç, Emrah; Salamov, Bahtiyar G.

2018-02-01

We have analyzed the interaction between microdischarge and microporous zeolite electronic materials modified by silver (Ag0) nanoparticles (resistivity 1011 to 106 Ω cm) on the atmospheric pressure cold plasma generation in air. The generation and maintenance of stable cold plasma is studied according to the effect of the Ag0 nanoparticles. The role of charge carriers in mixed conductivity processes and electrical features of zeolite from low pressure to atmospheric pressure is analyzed in air microplasmas for both before and after breakdown regimes. The results obtained from the experiments indicate that Ag0 nanoparticles play a significant role in considerably reducing the breakdown voltage in plasma electronic devices with microporous zeolite electronic materials.

Artificial Pancreas Device Systems for the Closed-Loop Control of Type 1 Diabetes: What Systems Are in Development?

Science.gov (United States)

Trevitt, Sara; Simpson, Sue; Wood, Annette

2016-05-01

Closed-loop artificial pancreas device (APD) systems are externally worn medical devices that are being developed to enable people with type 1 diabetes to regulate their blood glucose levels in a more automated way. The innovative concept of this emerging technology is that hands-free, continuous, glycemic control can be achieved by using digital communication technology and advanced computer algorithms. A horizon scanning review of this field was conducted using online sources of intelligence to identify systems in development. The systems were classified into subtypes according to their level of automation, the hormonal and glycemic control approaches used, and their research setting. Eighteen closed-loop APD systems were identified. All were being tested in clinical trials prior to potential commercialization. Six were being studied in the home setting, 5 in outpatient settings, and 7 in inpatient settings. It is estimated that 2 systems may become commercially available in the EU by the end of 2016, 1 during 2017, and 2 more in 2018. There are around 18 closed-loop APD systems progressing through early stages of clinical development. Only a few of these are currently in phase 3 trials and in settings that replicate real life. © 2015 Diabetes Technology Society.

Investigation on the effect of temperature excursion on the helium defects of tungsten surface by using compact plasma device

International Nuclear Information System (INIS)

Takamura, S.; Miyamoto, T.; Tomida, Y.; Minagawa, T.; Ohno, N.

2011-01-01

The effects of temperature excursion on the helium defects of tungsten surface have been investigated by using compact plasma device AIT-PID (Aichi Institute of Technology - Plasma Irradiation Device). An initial stage of bubble formation has been identified with an order of smaller (sub-micron) bubbles and holes than those in the past in which the micron size is the standard magnitude. The radiation cooling has been detected when a blacking of tungsten surface coming from nanostructure formation is proceeding due to an increase in the emissivity. The temperature increase to the domain (∼1600 K) in bubble/hole formation from that in nanostructure formation has been found to bring a constriction in diameter and a reduction in length of fiber-form nanostructure.

Numerical Analysis of Amirkabir Plasma Focus (APF) Device for Neon and Argon Gases

Science.gov (United States)

Niknam Sharak, M.; Goudarzi, S.; Raeisdana, A.; Jafarabadi, M.

2013-04-01

In this paper the experimental results in different working conditions in Amirkabir Plasma Focus (APF) Device have been compared with the numerical results of a two-dimensional simulation code based on Lee's model. The experiments were done with pure Neon and Argon as operating gases over a wide range of working conditions (gas pressures and discharge voltages). It is observed that by a proper choice for values of the efficiency factors, comparison between numerical and experimental results shows a good agreement.

Laboratory Studies on the Charging of Dust Grains in a Plasma

Science.gov (United States)

Xu, Wenjun

1993-01-01

The charging of dust grains by the surrounding plasma is studied in a dusty plasma device (DPD) (Xu, W., B. Song, R. L. Merlino, and N. D'Angelo, Rev. Sci. Instrum., 63, 5266, 1992). The dusty plasma device consists of a rotating-drum dust dispersal device used in conjunction with an existing Q-machine, to produce extended, steady state, magnetized plasma columns. The dust density in the dust chamber is controlled by the drum rotation speed. The device is capable of generating a dusty plasma in which as much as about 90% of the negative charge is attached to the dust grains of 1-10mu m size. Measurements of the dust parameter eta, the percentage of negative charge on free electrons in the dusty plasma, are presented. The dust parameter eta is found to depend on the rotational speed of the dust chamber, plasma density and the type and size of different dust. The dust parameter eta is calculated from a pair of Langmuir curves taken with and without dust under the same conditions. The operation of the dust chamber as described above has been confirmed by the agreement between the measurements of eta and the direct mechanical measurements consisting of weighing dust samples collected within the rotation dust chamber, at different rotation rates. By varying the ratio d/lambda_ {rm D} between the intergrain distance and the plasma Debye length, the effects predicted by Goertz and Ip (Goertz, C. K., and W-H. Ip, Geophys. Res. Lett., 11, 349, 1984), and subsequently reanalyzed in a more general fashion by Whipple et al. (Whipple, E. C., T. G. Northrop, and D. A. Mendis, J. Geophys. Rev., 90, 7405, 1985), as "isolated" dust grains become "closely packed" grains, have been demonstrated experimentally (Xu, W., N. D'Angelo, and R. L. Merlino, J. Geophys. Rev., 98, 7843, 1993). Similar results are presented and compared for two types of dust, kaolin and Al_2O _3, which have been studied in the experiment.

Rational surfaces, ExB sheared flows and transport interplay in fusion plasmas

International Nuclear Information System (INIS)

Hidalgo, Carlos; Pedrosa, Maria A.; Erents, Kevin

2001-01-01

Experimental evidence of a strong interplay between magnetic topology (rational surfaces) and the generation of ExB sheared flows has been observed in the plasma edge region of stellarator (TJ-II) and tokamak (JET) devices. Constant and varying in time ExB sheared flows are close to the critical value to trigger the transition to improved confinement regimes. The plasma conditions where this has been observed are clearly below the power threshold to trigger the formation of transport barriers. Flows driven by fluctuations are candidates to explain these experimental results. (author)

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.

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)

Non-inductive Solenoid-less Plasma Current Start-up in NSTX Using Transient CHI

International Nuclear Information System (INIS)

Raman, R.; Mueller, D.; Jarboe, T.R.; Nelson, B.A.; Bell, M.G.; Ono, M.; Bigelow, T.; Kaita, R.; LeBlanc, B.; Lee, K.C.; Maqueda, R.; Menard, J.; Paul, S.; Roquemore, L.

2007-01-01

Coaxial Helicity Injection (CHI) has been successfully used in the National Spherical Torus Experiment (NSTX) for a demonstration of closed flux current generation without the use of the central solenoid. The favorable properties of the Spherical Torus (ST) arise from its very small aspect ratio. However, small aspect ratio devices have very restricted space for a substantial central solenoid. Thus methods for initiating the plasma current without relying on induction from a central solenoid are essential for the viability of the ST concept. CHI is a promising candidate for solenoid-free plasma startup in a ST. The method has now produced closed flux current up to 160 kA verifying the high current capability of this method in a large ST built with conventional tokamak components.

Elements of plasma technology

CERN Document Server

Wong, Chiow San

2016-01-01

This book presents some fundamental aspects of plasma technology that are important for beginners interested to start research in the area of plasma technology . These include the properties of plasma, methods of plasma generation and basic plasma diagnostic techniques. It also discusses several low cost plasma devices, including pulsed plasma sources such as plasma focus, pulsed capillary discharge, vacuum spark and exploding wire; as well as low temperature plasmas such as glow discharge and dielectric barrier discharge which the authors believe may have potential applications in industry. The treatments are experimental rather than theoretical, although some theoretical background is provided where appropriate. The principles of operation of these devices are also reviewed and discussed.

Development of high energy pulsed plasma simulator for plasma-lithium trench experiment

Science.gov (United States)

Jung, Soonwook

To simulate detrimental events in a tokamak and provide a test-stand for a liquid lithium infused trench (LiMIT) device, a pulsed plasma source utilizing a theta pinch in conjunction with a coaxial plasma accelerator has been developed. An overall objective of the project is to develop a compact device that can produce 100 MW/m2 to 1 GW/m2 of plasma heat flux (a typical heat flux level in a major fusion device) in ~ 100 mus (≤ 0.1 MJ/m2) for a liquid lithium plasma facing component research. The existing theta pinch device, DEVeX, was built and operated for study on lithium vapor shielding effect. However, a typical plasma energy of 3 - 4 kJ/m2 is too low to study an interaction of plasma and plasma facing components in fusion devices. No or little preionized plasma, ringing of magnetic field, collisions of high energy particles with background gas have been reported as the main issues. Therefore, DEVeX is reconfigured to mitigate these issues. The new device is mainly composed of a plasma gun for a preionization source, a theta pinch for heating, and guiding magnets for a better plasma transportation. Each component will be driven by capacitor banks and controlled by high voltage / current switches. Several diagnostics including triple Langmuir probe, calorimeter, optical emission measurement, Rogowski coil, flux loop, and fast ionization gauge are used to characterize the new device. A coaxial plasma gun is manufactured and installed in the previous theta pinch chamber. The plasma gun is equipped with 500 uF capacitor and a gas puff valve. The increase of the plasma velocity with the plasma gun capacitor voltage is consistent with the theoretical predictions and the velocity is located between the snowplow model and the weak - coupling limit. Plasma energies measured with the calorimeter ranges from 0.02 - 0.065 MJ/m2 and increases with the voltage at the capacitor bank. A cross-check between the plasma energy measured with the calorimeter and the triple probe

Serum and plasma for total and free anticonvulsant drug analyses: effects on EMIT assays and ultrafiltration devices.

Science.gov (United States)

Godolphin, W; Trepanier, J; Farrell, K

1983-01-01

The suitability of serum and plasma anticoagulated with heparin, EDTA, citrate, or oxalate was assessed for analysis of free and total phenytoin, carbamazepine, and valproic acid. The free fraction was isolated by ultrafiltration through FreeLevel devices (Syva, Palo Alto, CA). Serum, heparin, and EDTA plasma were satisfactory for both free and total phenytoin and carbamazepine. EDTA could not be used for EMIT (Syva) analysis of valproate. Citrate and, to a lesser degree, oxalate cause a significant negative interference in the concentration of these three drugs as measured both by EMIT and gas-liquid chromatography.

Apparatus and method for removing particle species from fusion-plasma-confinement devices

Science.gov (United States)

Hamilton, G.W.

1981-10-26

In a mirror fusion plasma confinement apparatus, method and apparatus are provided for selectively removing (pumping) trapped low energy (thermal) particle species from the end cell region, without removing the still useful high energy particle species, and without requiring large power input to accomplish the pumping. Perturbation magnets are placed in the thermal barrier region of the end cell region at the turning point characteristic of trapped thermal particles, thus deflecting the thermal particles from their closed trajectory, causing them to drift sufficiently to exit the thermal barrier.

Assessment of image quality in x-ray radiography imaging using a small plasma focus device

Science.gov (United States)

Kanani, A.; Shirani, B.; Jabbari, I.; Mokhtari, J.

2014-08-01

This paper offers a comprehensive investigation of image quality parameters for a small plasma focus as a pulsed hard x-ray source for radiography applications. A set of images were captured from some metal objects and electronic circuits using a low energy plasma focus at different voltages of capacitor bank and different pressures of argon gas. The x-ray source focal spot of this device was obtained to be about 0.6 mm using the penumbra imaging method. The image quality was studied by several parameters such as image contrast, line spread function (LSF) and modulation transfer function (MTF). Results showed that the contrast changes by variations in gas pressure. The best contrast was obtained at a pressure of 0.5 mbar and 3.75 kJ stored energy. The results of x-ray dose from the device showed that about 0.6 mGy is sufficient to obtain acceptable images on the film. The measurements of LSF and MTF parameters were carried out by means of a thin stainless steel wire 0.8 mm in diameter and the cut-off frequency was obtained to be about 1.5 cycles/mm.

Convergent-close-coupling calculations for excitation and ionization processes of electron-hydrogen collisions in Debye plasmas

International Nuclear Information System (INIS)

Zammit, Mark C.; Fursa, Dmitry V.; Bray, Igor

2010-01-01

Electron-hydrogen scattering in weakly coupled hot-dense plasmas has been investigated using the convergent-close-coupling method. The Yukawa-type Debye-Hueckel potential has been used to describe the plasma screening effects. The target structure, excitation dynamics, and ionization process change dramatically as the screening is increased. Excitation cross sections for the 1s→2s,2p,3s,3p,3d and 2s→2p,3s,3p,3d transitions and total and total ionization cross sections for the scattering from the 1s and 2s states are presented. Calculations cover the energy range from thresholds to high energies (250 eV) for various Debye lengths. We find that as the screening increases, the excitation and total cross sections decrease, while the total ionization cross sections increase.

Effect of Equilibrium Flow on Plasma Parameters

International Nuclear Information System (INIS)

Mukhopadhyay, S.; Lahiri, S.; Sakanaka, P.H.; Dasgupta, B.

2003-01-01

The transition to high confinement modes have been identified with the occurrence of strong shear flow near the plasma boundary. Plasma flow has also been associated with various instabilities, heating and other physical processes. As a result, it has become very important to study the effect of such flows on various plasma parameters. In this paper, we present the numerical solution of plasma equilibrium with incompressible toroidal and poloidal flows in several magnetic confinement configurations including tokamaks. The code, which was reported in the last conference, has been used to solve the problem in both circular and D-shaped devices. A parametric study on the generation of shear flow due to radial electric fields has been carried out. Through this study, it has been possible to generate plasma equilibria having sharp pressure gradients which are remarkably close to those reported in various H-mode experiments. The effects of flow on reverse shear equilibria and on the position of the magnetic axis has been studied. Finally, a detailed study has been carried out to understand the effect of flows on important plasma parameters, such as the poloidal flux function, β, energy confinement time

Open loop control of filament heating power supply for large volume plasma device

Energy Technology Data Exchange (ETDEWEB)

Sugandhi, R., E-mail: ritesh@ipr.res.in [Institute for Plasma Research, Gandhinagar, Gujarat 382428 (India); Homi Bhabha National Institute, Mumbai 400094 (India); Srivastava, P.K.; Sanyasi, A.K. [Homi Bhabha National Institute, Mumbai 400094 (India); Srivastav, Prabhakar [Institute for Plasma Research, Gandhinagar, Gujarat 382428 (India); Homi Bhabha National Institute, Mumbai 400094 (India); Awasthi, L.M., E-mail: kushagra.lalit@gmail.com [Institute for Plasma Research, Gandhinagar, Gujarat 382428 (India); Homi Bhabha National Institute, Mumbai 400094 (India); Mattoo, S.K. [Homi Bhabha National Institute, Mumbai 400094 (India)

2017-02-15

A power supply (20 V, 10 kA) for powering the filamentary cathode has been procured, interfaced and integrated with the centralized control system of Large Volume Plasma Device (LVPD). Software interface has been developed on the standard Modbus RTU communication protocol. It facilitates the dashboard for configuration, on line status monitoring, alarm management, data acquisition, synchronization and controls. It has been tested for stable operation of the power supply for the operational capabilities. The paper highlights the motivation, interface description, implementation and results obtained.

Open loop control of filament heating power supply for large volume plasma device

International Nuclear Information System (INIS)

Sugandhi, R.; Srivastava, P.K.; Sanyasi, A.K.; Srivastav, Prabhakar; Awasthi, L.M.; Mattoo, S.K.

2017-01-01

A power supply (20 V, 10 kA) for powering the filamentary cathode has been procured, interfaced and integrated with the centralized control system of Large Volume Plasma Device (LVPD). Software interface has been developed on the standard Modbus RTU communication protocol. It facilitates the dashboard for configuration, on line status monitoring, alarm management, data acquisition, synchronization and controls. It has been tested for stable operation of the power supply for the operational capabilities. The paper highlights the motivation, interface description, implementation and results obtained.

Behavior of plasma facing surface in the large helical device

International Nuclear Information System (INIS)

Hino, T.; Nobuta, Y.; Sagara, A.

2002-10-01

Material probes have been installed at the inner walls along poloidal direction in LHD from the first experimental campaign. After each the campaign, the impurity deposition and the gas retention have been examined to clarify the plasma surface interaction and the degree of wall cleaning. In the 2nd campaign, the entire wall was considerably cleaned by helium glow discharge conditionings. For the 3rd and 4th campaigns, graphite tiles were installed at entire divertor strike region, and then the wall condition significantly changed compared to the case of stainless steel wall. The erosion of graphite took place during the main discharges and the eroded carbon deposited on the entire wall. In particular, the deposition thickness was large at the wall far from the plasma. Since the entire wall was well carbonized, amount of retained discharge gas such as H and He became large. In particular, the helium retention was large at the position close to the anodes used for helium glow discharge cleanings. One characteristics of the LHD wall is a large retention of helium gas since the wall temperature is limited below 368 K. In order to reduce the recycling of discharge gas, the wall heating before the experimental campaign and the surface heating between the main discharge shots are planned. (author)

Behavior of plasma facing surface in the large helical device

International Nuclear Information System (INIS)

Hino, T.; Nobuta, Y.; Sagara, A.

2002-01-01

Material probes have been installed at the inner walls along poloidal direction in LHD from the first experimental campaign. After each campaign, the impurity deposition and the gas retention have been examined to clarify the plasma surface interaction and the degree of wall cleaning. In the 2nd campaign, the entire wall was considerably cleaned by helium glow discharge conditionings. For the 3rd and 4th campaigns, graphite tiles were installed at entire divertor strike region, and then the wall condition significantly changed compared to the case of stainless steel wall. The erosion of graphite took place during the main discharges and the eroded carbon deposited on the entire wall. In particular, the deposition thickness was large at the wall far from the plasma. Since the entire wall was well carbonized, amount of retained discharge gas such as H and He became large. In particular, the helium retention was large at the position close to the anodes used for helium glow discharge cleanings. One characteristics of the LHD wall is a large retention of helium gas since the wall temperature is limited below 368 K. In order to reduce the recycling of discharge gas, the wall heating before the experimental campaign and the surface heating between the main discharge shots are planned. (author)

Behavior of plasma facing surface in the large helical device

Energy Technology Data Exchange (ETDEWEB)

Hino, T.; Nobuta, Y. [Hokkaido Univ., Dept. of Nuclear Engineering, Sapporo, Hokkaido (Japan); Sagara, A. [National Inst. for Fusion Science, Toki, Gifu (Japan)] [and others

2002-11-01

Material probes have been installed at the inner walls along poloidal direction in LHD from the first experimental campaign. After each campaign, the impurity deposition and the gas retention have been examined to clarify the plasma surface interaction and the degree of wall cleaning. In the 2nd campaign, the entire wall was considerably cleaned by helium glow discharge conditionings. For the 3rd and 4th campaigns, graphite tiles were installed at entire divertor strike region, and then the wall condition significantly changed compared to the case of stainless steel wall. The erosion of graphite took place during the main discharges and the eroded carbon deposited on the entire wall. In particular, the deposition thickness was large at the wall far from the plasma. Since the entire wall was well carbonized, amount of retained discharge gas such as H and He became large. In particular, the helium retention was large at the position close to the anodes used for helium glow discharge cleanings. One characteristics of the LHD wall is a large retention of helium gas since the wall temperature is limited below 368 K. In order to reduce the recycling of discharge gas, the wall heating before the experimental campaign and the surface heating between the main discharge shots are planned. (author)

Effects of Non-Maxwellian Plasma Species on ICRF Propagation and Absorption in Toroidal Magnetic Confinement Devices

International Nuclear Information System (INIS)

Dumont, R.J.; Phillips, C.K.; Smithe, D.N.

2003-01-01

Auxiliary heating supplied by externally launched electromagnetic waves is commonly used in toroidal magnetically confined fusion experiments for profile control via localized heating, current drive and perhaps flow shear. In these experiments, the confined plasma is often characterized by the presence of a significant population of non-thermal species arising from neutral beam injection, from acceleration of the particles by the applied waves, or from copious fusion reactions in future devices. Such non-thermal species may alter the wave propagation as well as the wave absorption dynamics in the plasma. Previous studies have treated the corresponding velocity distributions as either equivalent Maxwellians, or else have included realistic distributions only in the finite Larmor radius limit. In this work, the hot plasma dielectric response of the plasma has been generalized to treat arbitrary distribution functions in the non-relativistic limit. The generalized dielectric tensor has been incorporated into a one-dimensional full wave all-orders kinetic field code. Initial comparative studies of ion cyclotron range of frequency wave propagation and heating in plasmas with nonthermal species, represented by realistic distribution functions or by appropriately defined equivalent Maxwellians, have been completed for some specific experiments and are presented

Diagnostics of peripheric plasma in thermonuclear devices

International Nuclear Information System (INIS)

Vojtsenya, V.S.; Tereshin, V.I.

1986-01-01

Review of basic methods, applied or developed for peripheral plasma diagnostics is given, including electric probes of various types, collecting probes for studying impurity ion and main plasma component characteristics, spectroscopic and corpuscular-optical methods, laser fluorescence spectroscopy, mass-spectrometry, heavy ion and atom (lithium and hydrogen) beam methods. Ranges of plasma parameters their measurements being provided by the methods indicated are presented

40 CFR 63.7927 - What are my inspection and monitoring requirements for closed vent systems and control devices?

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 13 2010-07-01 2010-07-01 false What are my inspection and monitoring... Pollutants: Site Remediation Closed Vent Systems and Control Devices § 63.7927 What are my inspection and... temperature at the inlet of the catalyst bed, the hourly average temperature at the outlet of the catalyst bed...

The kINPen—a review on physics and chemistry of the atmospheric pressure plasma jet and its applications

Science.gov (United States)

Reuter, Stephan; von Woedtke, Thomas; Weltmann, Klaus-Dieter

2018-06-01

The kINPen® plasma jet was developed from laboratory prototype to commercially available non-equilibrium cold plasma jet for various applications in materials research, surface treatment and medicine. It has proven to be a valuable plasma source for industry as well as research and commercial use in plasma medicine, leading to very successful therapeutic results and its certification as a medical device. This topical review presents the different kINPen plasma sources available. Diagnostic techniques applied to the kINPen are introduced. The review summarizes the extensive studies of the physics and plasma chemistry of the kINPen performed by research groups across the world, and closes with a brief overview of the main application fields.

Quiescent plasma machine for plasma investigation

International Nuclear Information System (INIS)

Ferreira, J.L.

1993-01-01

A large volume quiescent plasma device is being developed at INPE to study Langmuir waves and turbulence generated by electron beams (E b ≤ 500 e V) interacting with plasma. This new quiescent plasma machine was designed to allow the performance of several experiments specially those related with laboratory space plasma simulation experiments. Current-driven instabilities and related phenomena such as double-layers along magnetic field lines are some of the many experiments planned for this machine. (author)

Electronic and optical device applications of hollow cathode plasma assisted atomic layer deposition based GaN thin films

International Nuclear Information System (INIS)

Bolat, Sami; Tekcan, Burak; Ozgit-Akgun, Cagla; Biyikli, Necmi; Okyay, Ali Kemal

2015-01-01

Electronic and optoelectronic devices, namely, thin film transistors (TFTs) and metal–semiconductor–metal (MSM) photodetectors, based on GaN films grown by hollow cathode plasma-assisted atomic layer deposition (PA-ALD) are demonstrated. Resistivity of GaN thin films and metal-GaN contact resistance are investigated as a function of annealing temperature. Effect of the plasma gas and postmetallization annealing on the performances of the TFTs as well as the effect of the annealing on the performance of MSM photodetectors are studied. Dark current to voltage and responsivity behavior of MSM devices are investigated as well. TFTs with the N 2 /H 2 PA-ALD based GaN channels are observed to have improved stability and transfer characteristics with respect to NH 3 PA-ALD based transistors. Dark current of the MSM photodetectors is suppressed strongly after high-temperature annealing in N 2 :H 2 ambient

Physics of photonic devices

CERN Document Server

Chuang, Shun Lien

2009-01-01

The most up-to-date book available on the physics of photonic devices This new edition of Physics of Photonic Devices incorporates significant advancements in the field of photonics that have occurred since publication of the first edition (Physics of Optoelectronic Devices). New topics covered include a brief history of the invention of semiconductor lasers, the Lorentz dipole method and metal plasmas, matrix optics, surface plasma waveguides, optical ring resonators, integrated electroabsorption modulator-lasers, and solar cells. It also introduces exciting new fields of research such as:

The {open_quotes}first{close_quotes} problem

Energy Technology Data Exchange (ETDEWEB)

Holsinger, R.F.

1995-02-01

This paper describes the first magnet design problem that Klaus and the author worked on together. At the time, over 30 years ago, Klaus was working as a plasma physicist in the Controlled Thermonuclear Research (CTR) Group, and the author was assigned from the Mechanical Engineering Department to help with the design of experimental equipment for various research projects. Klaus` primary research program was to develop a {open_quotes}plasma gun{close_quotes} for injecting plasma into {open_quotes}mirror machines.{close_quotes} As described, the magnet design aspect of this plasma gun was a challenging task, and led to some innovations that were quite advanced at that time.

Nonlinear dynamics and plasma transport

International Nuclear Information System (INIS)

Liu, C.S.; Sagdeev, R.; Antonsen, T.; Drake, J.; Hassma, A.; Guzdar, P.N.

1995-12-01

This progress report reports work done on a program in nonlinear dynamical aspects of plasma turbulence and transport funded by DOE from 1992-1995. The purpose of this program has been to promote the utilization of recent pathbreaking developments in nonlinear science in plasma turbulence and transport and to fully utilize the scientific expertise of Russian fusion and plasma community in collaboration with our group to address outstanding fusion theory problems. In the work reported in our progress report, we have studied simple models which are motivated by observation on actual fusion devices. The models focus on the important physical processes without incorporating the complexity of the geometry of real devices. We have also studied linear stability problems which incorporated important physics issues related to geometry involving closed field lines and open field lines. This allows for a deeper analysis and understanding of the system both analytically and numerically. The strong collaboration between the Russian visitors and the US participants has led to a fruitful and strong research program that taps the complementary analytic and numerical capabilities of the two groups. Over the years several distinguished Russian visitors have interacted with various members of the group and set up collaborative work which forms a significant part of proposed research. Dr. Galeev, Director of the Space Research Institute of Moscow and Dr. Novakovskii from the Kurchatov Institute are two such ongoing collaborations. 21 refs

Engineering prototypes for theta-pinch devices

International Nuclear Information System (INIS)

Hansborough, L.D.; Hammer, C.F.; Hanks, K.W.; McDonald, T.E.; Nunnally, W.C.

1975-01-01

Past, present, and future engineering prototypes for theta-pinch plasma-physics devices at Los Alamos Scientific Laboratory are discussed. Engineering prototypes are designed to test and evaluate all components under system conditions expected on actual plasma-physics experimental devices. The importance of engineering prototype development increases as the size and complexity of the plasma-physics device increases. Past experiences with the Scyllac prototype and the Staged Theta-Pinch prototype are discussed and evaluated. The design of the proposed Staged Scyllac prototype and the Large Staged Scyllac implosion prototype assembly are discussed

Fabrication of hybrid molecular devices using multi-layer graphene break junctions

Science.gov (United States)

Island, J. O.; Holovchenko, A.; Koole, M.; Alkemade, P. F. A.; Menelaou, M.; Aliaga-Alcalde, N.; Burzurí, E.; van der Zant, H. S. J.

2014-11-01

We report on the fabrication of hybrid molecular devices employing multi-layer graphene (MLG) flakes which are patterned with a constriction using a helium ion microscope or an oxygen plasma etch. The patterning step allows for the localization of a few-nanometer gap, created by electroburning, that can host single molecules or molecular ensembles. By controlling the width of the sculpted constriction, we regulate the critical power at which the electroburning process begins. We estimate the flake temperature given the critical power and find that at low powers it is possible to electroburn MLG with superconducting contacts in close proximity. Finally, we demonstrate the fabrication of hybrid devices with superconducting contacts and anthracene-functionalized copper curcuminoid molecules. This method is extendable to spintronic devices with ferromagnetic contacts and a first step towards molecular integrated circuits.

High current vacuum closing switch

International Nuclear Information System (INIS)

Dolgachev, G.I.; Maslennikov, D.D.; Romanov, A.S.; Ushakov, A.G.

2005-01-01

The paper proposes a powerful pulsed closing vacuum switch for high current commutation consisting of series of the vacuum diodes with near 1 mm gaps having closing time determined by the gaps shortening with the near-electrode plasmas [ru

Fast photography of XeCl laser-induced plasma of graphite in vacuum and in nitrogen atmosphere

International Nuclear Information System (INIS)

Acquaviva, S; De Giorgi, M L

2003-01-01

Fast photography with a gated intensified close-coupled device camera was applied to provide a visualization of the temporal and spatial evolution of chemical species in a plasma induced by a 308 nm laser during graphite ablation, in vacuum and in nitrogen atmosphere. A sequence of frames of the luminous plume was recorded, using narrow interference filters, and plasma expansion velocity was estimated from the acquired images. Present observations agree with optical emission spectroscopic investigations performed under the same experimental conditions

On the link between ExB sheared flows and rational surfaces in fusion plasmas

International Nuclear Information System (INIS)

Hidalgo, C.; Erents, K.; Matthews, G.

2000-11-01

Experimental evidence of flattening in plasma profiles has been observed in the edge region of the JET tokamak. This observation has been interpreted in terms of the influence of rational surfaces on plasma profiles. In the framework of this interpretation, significant ExB sheared flows linked to rational surfaces have been identified. These ExB sheared flows are close to the critical value to trigger the transition to improved confinement regimes. These results can explain the link between the magnetic topology and the generation of transport barriers reported in fusion devices. (author)

Synthesis of nanostructured multiphase Ti(C,N)/a-C films by a plasma focus device

International Nuclear Information System (INIS)

Ghareshabani, E.; Rawat, R.S.; Sobhanian, S.; Verma, R.; Karamat, S.; Pan, Z.Y.

2010-01-01

Nanostructured multiphase Ti(C,N)/a-C films were deposited using a 3.3 kJ pulsed plasma focus device onto silicon (1 0 0) substrates at room temperature. The plasma focus device, fitted with solid titanium anode instead of usual hollow copper anode, was operated with nitrogen and Ar/CH 4 as the filling gas. Films were deposited with different number of shots, at 80 mm from top of the anode and at zero angular position with respect to anode axis. X-ray diffraction results show the diffraction peaks related to different compounds such as TiC 2 , TiN, Ti 2 CN, Ti and TiC 0.62 confirming the deposition of multiphase titanium carbo-nitride composite films on silicon. X-ray photoelectron spectroscopy confirms the formation of Ti-C, C-N, Ti-N, Ti-O and C-C bonds in the films. Scanning electron microscopy reveals that the nanostructure grains are agglomerates of smaller nanoparticles about 10-20 nm in size. Raman studies verify the formation of multiphase Ti(C,N) and also of amorphous graphite in the films. The maximum microhardness value of the composite film is 14.8 ± 1.3 GPa for 30 shots.

Design of closed-loop nitrogen Joule-Thomson refrigeration cycle for 67 K with sub-atmospheric device

Energy Technology Data Exchange (ETDEWEB)

Lee, C.; Lee, J.; Jeong, S. [Cryogenic Engineering Laboratory, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2013-05-15

Closed-loop J-T (Joule-Thomson) refrigeration cycle is advantageous compared to common open loop N{sub 2} decompression system in terms of nitrogen consumption. In this study, two closed-loop pure N{sub 2} J-T refrigeration systems with sub-atmospheric device for cooling High Temperature Superconductor (HTS) power cable are investigated. J-T cooling systems include 2-stage compressor, 2-stage precooling cycle, J-T valve and a cold compressor or an auxiliary vacuum pump at the room temperature. The cold compressor and the vacuum pump are installed after the J-T valve to create sub-atmospheric condition. The temperature of 67 K is possible by lowering the pressure up to 24 kPa at the cold part. The optimized hydrocarbon mixed refrigerant (MR) J-T system is applied for precooling stage. The cold head of precooling MR J-T have the temperature from 120 K to 150 K. The various characteristics of cold compressor are investigated and applied to design parameter of the cold compressor. The Carnot efficiency of cold compressor system is calculated as 16.7% and that of vacuum pump system as 16.4%. The efficiency difference between the cold compressor system and the vacuum pump system is due to difference of enthalpy change at cryogenic temperature, enthalpy change at room temperature and different work load at the pre-cooling cycle. The efficiency of neon-nitrogen MR J-T system is also presented for comparison with the sub-atmospheric devices. These systems have several pros and cons in comparison to typical MR J-T systems such as vacuum line maintainability, system's COP and etc. In this paper, the detailed design of the subcooled N{sub 2} J-T systems are examined and some practical issues of the sub-atmospheric devices are discussed.

Dynamics of three-dimensional radiative structures during RMP assisted detached plasmas on the large helical device and its comparison with EMC3-EIRENE modeling

Science.gov (United States)

Pandya, Shwetang N.; Peterson, Byron J.; Kobayashi, Masahiro; Ida, Katsumi; Mukai, Kiyofumi; Sano, Ryuichi; Miyazawa, Junichi; Tanaka, Hirohiko; Masuzaki, Suguru; Akiyama, Tsuyoshi; Motojima, Gen; Ohno, Noriyasu; LHD Experiment Group

2016-04-01

The resonant magnetic perturbation (RMP) island introduced in the stochastic edge of the large helical device (LHD) plasma plays an important role in the stabilization of the plasma detachment (Kobayashi et al 2013 Nucl. Fusion 53 093032). The plasma enters in the sustained detachment phase in the presence of an RMP once the line averaged density exceeds a critical value with a given input power. During detachment the enhanced radiation from the stochastic edge of the LHD undergoes several spatiotemporal changes which are studied quantitatively by an infrared imaging video bolometer (IRVB) diagnostic. The experimental results are compared qualitatively and quantitatively with the radiation predicted by the 3D transport simulation with fluid model, EMC3-EIRENE. A fair amount of qualitative agreement, before and after the detachment, is reported. The issue of overestimated radiation from the model is addressed by changing the free parameters in the EMC3-EIRENE code till the total radiation and the radiation profiles match closely, within a factor of two with the experimental observations. A better quantitative match between the model and the experiment is achieved at higher cross-field impurity diffusion coefficient and lower sputtering coefficient after the detachment. In this article a comparison, the first of its kind, is established between the quantified radiation from the experiments and the synthetic image obtained from the simulation code. This exercise is aimed towards validating the model assumptions against the experimentally measured radiation.

Behavior of plasma facing surfaces in the large helical device

International Nuclear Information System (INIS)

Hino, T.; Nobuta, Y.; Sagara, A.

2003-01-01

Material probes have been installed at the inner walls along the poloidal direction in LHD from the first experimental campaign. After each campaign, the impurity deposition and the gas retention have been examined to clarify the plasma surface interaction and the degree of wall cleaning. In the 2nd campaign, the entire wall was thoroughly cleaned by helium glow discharge conditioning. For the 3rd and 4th campaigns, graphite tiles were installed over the entire divertor strike region, and then the wall condition was significantly changed compared to the case of a stainless steel wall. Graphite erosion took place during the main discharges and the eroded carbon was deposited on the entire wall. In particular, the deposition thickness was large at the wall far from the plasma. Since the entire wall was well carbonized, the amount of retained discharge gases such as H and He became large. In particular, the helium retention was large at the position close to the anodes used for helium glow discharge cleanings. One characteristic of the LHD wall is a large retention of helium gas since the wall temperature is limited to below 368 K. In order to reduce the recycling of discharge gas, wall heating before the experimental campaign and surface heating between the main discharge shots are planned. (author)

New Modular Heliotron system compatible with closed helical divertor and good plasma confinement

International Nuclear Information System (INIS)

Yamazaki, K.; Watanabe, K.Y.

1994-04-01

A new helical system ('Modular Heliotron') with improved modular coils compatible with efficient closed helical divertor and good plasma confinement property is proposed based on a Heliotron system with continuous helical coils and one pair of poloidal coils. The physics optimization of this system as a function of the gap angle between adjacent modular coils has been carried out by means of vacuum magnetic surface calculations and finite-beta plasma analyses, and a new improved coil system is invented by combining sectored helical field coils with sectored returning poloidal field coils. The Modular Heliotron with standard coil winding law (reference Modular Heliotron) was previously proposed, but it is found that this is not appropriate to keep clean helical divertor and high beta configuration when the coil gap becomes large. By modulating the modular coil winding with outside-plus and inside-minus pitch modulation, almost the same good magnetic configuration as that of a conventional Heliotron can be produced. The optimal gap angle is determined as a function of the modulation parameter. This improved Modular Heliotron permits larger gap angle between adjacent modules and produces more clean helical divertor configuration than the reference Modular Heliotron. All these helical system are created by only modular coils without poloidal coils. (author)

Fueling of magnetic-confinement devices

International Nuclear Information System (INIS)

Milora, S.L.

1981-01-01

A general overview of the fueling of magnetic confinement devices is presented, with particular emphasis on recent experimental results. Various practical fueling mechanisms are considered, such as cold gas inlet (or plasma edge fueling), neutral beam injection, and injection of high speed cryogenic hydrogen pellets. The central role played by charged particle transport and recycle of plasma particles from material surfaces in contact with the plasma is discussed briefly. The various aspects of hydrogen pellet injection are treated in detail, including applications to the production of high purity startup plasmas for stellarators and other devices, refueling of tokamak plasmas, pellet ablation theory, and the technology and performance characteristics of low and high speed pellet injectors

Tornado type closed magnetic trap for an ECR source

CERN Document Server

Abramova, K B; Voronin, A V; Zorin, V G

1999-01-01

We propose to use a Tornado type closed magnetic trap for creation of a source of mul-ticharged ions with plasma heating by microwave radiation. Plasma loss in closed traps is deter-mined by diffusion across the magnetic field, which increases substantially plasma confinement time as compared to the classical mirror trap [1]. We propose to extract ions with the aid of additional coils which partially destroy the closed structure of the magnetic lines in the trap, but don not influence the total confinement time. This allows for producing a controlled plasma flux that depends on the magnetic field of the additional coil. The Tornado trap also possesses merits such as an opportunity to produce high magnetic fields up to 3 T, which makes possible heating and confinement of plasma with a high density of electrons; plasma stability to magneto-hydrodynamic perturbations because the magnetic field structure corresponds to the "min B" configuration; and relatively low costs. All estimates and calculations were carrie...

A method for measuring plasma position in the rectangular tokamak TJ-I

International Nuclear Information System (INIS)

Qin, J.; Ascasibar, E.; Pastor, I.; Navarro, A.P.; Ochando, M.A.; Pedrosa, M.A.; Rodriguez, L.; Sanchez, J.

1993-01-01

Determinations of plasma position in tokamaks are based on measuring the external magnetic field of the plasma current. Usually, the measurements are performed with magnetic coils along a closed contour around the plasma column, or with small magnetic probes in pairs positioned diametrically. However, such measurements are constrained in TJ-I because of a severe restriction on installing the magnetic probes. It is only possible to install some small magnetic probes inside the vacuum vessel near its top and bottom walls where the limiters stand. In this paper an alternative method of measuring plasma position in TJ-I is presented. The plasma position can be derived from the measurements of those magnetic probes located off the equatorial plane, with the aid of a filament model. The method is proved to be reliable, and would be applied to those small-size devices with similar restrictions. (author) 5 refs., 3 figs., 1 tab

The numerical simulation of plasma flow in cylindrical resonant cavity of microwave plasma thruster

International Nuclear Information System (INIS)

Tang, J.-L.; He, H.-Q; Mao, G.-W.

2004-01-01

Microwave Plasma Thruster (MPT) is an electro-thermal propulsive device. MPT consists of microwave generator, gas storing and supplying system, resonant cavity and accelerative nozzle. It generates free-floating plasma brought by the microwave discharge breakdown gas in the resonant cavity, and the plasma exhausted from nozzle produces thrust. MPT has prospective application in spacecraft because of its advantages of high thrust, moderate specific impulse and high efficiency. In this paper, the numerical simulation of the coupling flow field of microwave plasma in resonant cavity under different frequencies will be discussed. The results of numerical simulation are as follows: 1) When the resonant model TM 011 was used, the higher the microwave frequency was, the smaller the size of MPT. The distribution of the electromagnetic field in small cavity, however, remain unchanged. 2) When the resonant model was used, the distribution of the temperature, the pressure and the electronic density in the resonant cavity remained unchanged under different resonant frequencies. 3) When the resonant frequency was increased with a fixed pressure distribution in a small cavity, compare to the MPT with lower frequency, the gas flow rate, the microwave power and the nozzle throat diameter of MPT all decreased. 4) The electromagnetic field in the cylindrical resonant cavity for all MPT with different frequencies was disturbed by the plasma formation. The strong disturbance happened in the region close to the plasma. (author)

A drift-ordered short mean-free path description of a partially ionized magnetized plasma

International Nuclear Information System (INIS)

Simakov, Andrei N

2009-01-01

Neutral particles that are present at the edge of plasma magnetic confinement devices can play an important role in energy and momentum transport, and their effects should be accounted for. This work uses the drift ordering to derive a closed fluid description for a collisional, magnetized, partially ionized plasma. Charge-exchange, ionization and recombination processes are taken into account. It is assumed that electron distribution function is unaffected by atomic processes, so that electron-ion momentum and energy exchange are described by the usual expressions for a fully ionized plasma, and that neutral-neutral collisions are unimportant. The collisional fluid equations derived herein generalize the drift-ordered description of a fully ionized collisional plasma (Catto P J et al 2004 Phys. Plasmas 11 90), agree with the MHD-ordered description of a partially ionized plasma (Helander P et al 1994 Phys. Plasmas 1 3174) in the large-flow limit and can be used to describe both turbulent and collisional behavior of a partially ionized plasma.

Characterization of the Plasma Edge for Technique of Atomic Helium Beam in the CIEMAT Fusion Device

International Nuclear Information System (INIS)

Hidalgo, A.

2003-01-01

In this report, the measurement of Electron Temperature and Density in the Boundary Plasma of TJ-II with a Supersonic Helium Beam Diagnostic and work devoted to the upgrading of this technique are described. Also, simulations of Laser Induced Fluorescence (LIF) studies of level populations of electronically excited He atoms are shown. This last technique is now being installed in the CIEMAT fusion device. (Author )

Investigation of the Effect of Plasma Polymerized Siloxane Coating for Enzyme Immobilization and Microfluidic Device Conception

Directory of Open Access Journals (Sweden)

Kalim Belhacene

2016-12-01

Full Text Available This paper describes the impact of a physical immobilization methodology, using plasma polymerized 1,1,3,3, tetramethyldisiloxane, on the catalytic performance of β-galactosidase from Aspergillus oryzae in a microfluidic device. The β-galactosidase was immobilized by a polymer coating grown by Plasma Enhanced Chemical Vapor Deposition (PEVCD. Combined with a microchannel patterned in the silicone, a microreactor was obtained with which the diffusion through the plasma polymerized layer and the hydrolysis of a synthetic substrate, the resorufin-β-d-galactopyranoside, were studied. A study of the efficiency of the immobilization procedure was investigated after several uses and kinetic parameters of immobilized β-galactosidase were calculated and compared with those of soluble enzyme. Simulation and a modelling approach were also initiated to understand phenomena that influenced enzyme behavior in the physical immobilization method. Thus, the catalytic performances of immobilized enzymes were directly influenced by immobilization conditions and particularly by the diffusion behavior and availability of substrate molecules in the enzyme microenvironment.

Experimental Study of Current Discharge Behavior and Hard X-ray Anisotropy by APF Plasma Focus Device

Science.gov (United States)

Habibi, M.; Amrollahi, R.; Attaran, M.

2009-03-01

Amirkabir (APF) is a new Mather-type plasma focus device (16 kV, 36 μf, and 115 nH). In this work we present some experimental results as variation of discharge current signal respect to applied voltage at the optimum pressure, focusing time of plasma versus gas pressure, and variations of current discharge with different insulator sleeve dimensions. As we prospected optimum pressure tending to increase as we tried to higher voltage levels. The time taken by the current sheath to lift-off the insulator surface and therefore quality of pinched plasma depends on the length of the insulator sleeve. The results show that the insulator diameter can influence on pinch quality. Behavior of hard X-ray (HXR) signals with the pressure and also anisotropy of HXR investigated by the use of two scintillation detectors. The distribution of HXR intensity shows a large anisotropy with a maximum intensity between 22.5° and 45° and also between -22.5° and -67.5°.

Device and method for relativistic electron beam heating of a high-density plasma to drive fast liners

International Nuclear Information System (INIS)

Thode, L.E.

1981-01-01

A device and method for relativistic electron beam heating of a high-density plasma in a small localized region are described. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises dt, dd, hydrogen boron or similar thermonuclear gas at a density of 1017 to 1020 electrons per cubic centimeter. The target gas is ionized prior to application of the electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 mev, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy and momentum into a small localized region of the high-density plasma target. Fast liners disposed in the high-density target plasma are explosively or ablatively driven to implosion by a heated annular plasma surrounding the fast liner which is generated by an annular relativistic electron beam. An azimuthal magnetic field produced by axial current flow in the annular plasma, causes the energy in the heated annular plasma to converge on the fast liner

The 26th IEEE international conference on plasma science

International Nuclear Information System (INIS)

1999-01-01

Some of the sessions covered by this conference are: Basic Processes in Fully and Partially Ionized Plasmas; Slow Wave Devices; Laser-Produced Plasma; Non-Equilibrium Plasma Processing; Space Plasmas and Partially Ionized Gases; Microwave Plasmas; Inertial Confinement Fusion; Plasma Diagnostics; Computational Plasma Physics; Microwave Systems; Laser Produced Plasmas and Dense Plasma Focus; Intense Electron and Ion Beams; Fast Wave Devices; Spherical Configurations and Ball Lightning; Thermal Plasma Chemistry and Processing and Environmental Issues in Plasma Science; Plasma, Ion, and Electron Sources; Fast Wave Devices and Intense Beams; Fast Z-pinches and X-ray Lasers; Plasma Opening Switches; Plasma for Lighting; Intense Beams; Vacuum Microwaves; Magnetic Fusion Energy; and Plasma Thrusters and Arcs. Separate abstracts were prepared for some of the papers in this volume

Liquid metals as a divertor plasma-facing material explored using the Pilot-PSI and Magnum-PSI linear devices

Science.gov (United States)

Morgan, T. W.; Rindt, P.; van Eden, G. G.; Kvon, V.; Jaworksi, M. A.; Lopes Cardozo, N. J.

2018-01-01

For DEMO and beyond, liquid metal plasma-facing components are considered due to their resilience to erosion through flowed replacement, potential for cooling beyond conduction and inherent immunity to many of the issues of neutron loading compared to solid materials. The development curve of liquid metals is behind that of e.g. tungsten however, and tokamak-based research is currently somewhat limited in scope. Therefore, investigation into linear plasma devices can provide faster progress under controlled and well-diagnosed conditions in assessing many of the issues surrounding the use of liquid metals. The linear plasma devices Magnum-PSI and Pilot-PSI are capable of producing DEMO-relevant plasma fluxes, which well replicate expected divertor conditions, and the exploration of physics issues for tin (Sn) and lithium (Li) such as vapour shielding, erosion under high particle flux loading and overall power handling are reviewed here. A deeper understanding of erosion and deposition through this work indicates that stannane formation may play an important role in enhancing Sn erosion, while on the other hand the strong hydrogen isotope affinity reduces the evaporation rate and sputtering yields for Li. In combination with the strong redeposition rates, which have been observed under this type of high-density plasma, this implies that an increase in the operational temperature range, implying a power handling range of 20-25 MW m-2 for Sn and up to 12.5 MW m-2 for Li could be achieved. Vapour shielding may be expected to act as a self-protection mechanism in reducing the heat load to the substrate for off-normal events in the case of Sn, but may potentially be a continual mode of operation for Li.

Compression of toroidal plasma by imploding plasma-liner

International Nuclear Information System (INIS)

Ikuta, Kazunari.

1979-07-01

A new concept of compressing a plasma in a closed magnetic configuration by a version of liner implosion flux compression technique is considered. The liner consists of a dense plasma cylinder, i.e. the plasma-liner. Maximum compression ratio of toroidal plasma is determined just by the initial density ratio of the toroidal plasma to the liner plasma because of the Rayleigh-Taylor instability. A start-up senario of plasma-liner is also proposed with a possible application of this concept to the creation of a burning plasma in reversed field configurations, i.e. burning plasma vortex. (author)

Collisional avalanche exponentiation of runaway electrons in electrified plasmas

International Nuclear Information System (INIS)

Jayakumar, R.; Fleischmann, H.H.; Zweben, S.J.

1993-01-01

In contrast to earlier expectations, it is estimated that generation of runaway electrons from close collisions of existing runaways with cold plasma electrons can be significant even for small electric fields, whenever runaways can gain energies of about 20 MeV or more. In that case, the runaway population will grow exponentially with the energy spectrum showing an exponential decrease towards higher energies. Energy gains of the required magnitude may occur in large tokamak devices as well as in cosmic-ray generation. (orig.)

Aqueous reactive species induced by a PCB surface micro-discharge air plasma device: a quantitative study

Science.gov (United States)

Chen, Chen; Li, Fanying; Chen, Hai-Lan; Kong, Michael G.

2017-11-01

This paper presents a quantitative investigation on aqueous reactive species induced by air plasma generated from a printed circuit board surface micro-discharge (SMD) device. Under the conditions amenable for proliferation of mammalian cells, concentrations of ten types of reactive oxygen and nitrogen species (RONS) in phosphate buffering solution (PBS) are measured by chemical fluorescent assays and electron spin resonance spectroscopy (ESR). Results show that concentrations of several detected RNS (NO2- , NO3- , peroxynitrites, and NO2\\centerdot ) are higher than those of ROS (H2O2, O2\\centerdot - , and 1O2) in the air plasma treated solution. Concentrations of NO3- can reach 150 times of H2O2 with 60 s plasma treatment. For short-lived species, the air plasma generates more copious peroxynitrite than other RONS including NO2\\centerdot , O2\\centerdot - , 1O2, and N{{O}\\centerdot } in PBS. In addition, the existence of reaction between H2O2 and NO2- /HNO2 to produce peroxynitrite is verified by the chemical scavenger experiments. The reaction relations between detected RONS are also discussed.

Ammonia formation and W coatings interaction with deuterium/nitrogen plasmas in the linear device GyM

Energy Technology Data Exchange (ETDEWEB)

Laguardia, L., E-mail: laguardia@ifp.cnr.it [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy); Caniello, R.; Cremona, A. [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy); Dellasega, D. [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy); Politecnico di Milano, Dipartimento di Energia, Milan (Italy); Dell’Era, F.; Ghezzi, F.; Gittini, G.; Granucci, G.; Mellera, V.; Minelli, D.; Pallotta, F. [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy); Passoni, M. [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy); Politecnico di Milano, Dipartimento di Energia, Milan (Italy); Ricci, D.; Vassallo, E. [CNR, Istituto di Fisica del Plasma“P. Caldirola”, Milan (Italy)

2015-08-15

In this work results of the first D{sub 2}/N{sub 2} experiments in GyM, a linear device able to produce plasmas of interest for the ITER divertor (n{sub e} 5 ⋅ 10{sup 10} cm{sup −3}, Te 5 eV, ion flux 3–5 ⋅ 10{sup 20} m{sup −2}s{sup −1}) are presented. Plasmas simulating a N-seeding scenario have been performed to evaluate ammonia formation and its effect on exposed W coatings. The presence of ND emission lines in the plasma can be correlated with the formation of ammonia, further directly detected and quantified by chromatography analysis of the exhaust. Four different W specimens were exposed in GyM to a plasma fluence of 8.78 ⋅ 10{sup 23} m{sup −2}. XPS analysis evidenced the formation of W{sub x}N{sub y} layers with nitrogen concentration in the range of 1–10% depending on the initial morphology and structure of the W samples. In all analyzed cases, nitrogen was bound and retained within the first 6 nm below the surface and no further diffusion of N into the bulk was observed.

TPA device for demonstration

International Nuclear Information System (INIS)

1980-02-01

The TPA (torus plasma for amature) is a small race-trac type device made by the technical service division to demonstrate basic properties of plasma such as electron temperature, conductivity, effect of helical field for toroidal drift, and shape of plasma in mirror and cusp magnetic field in linear section. The plasmas are produced by RF discharge (-500W) and/or DC discharge (-30 mA) within glass discharge tube. Where major radius is 50 cm, length of linear section is 50 cm, toroidal magnetic field is 200 gauss. The device has been designed to be compact with only 100 V power source (-3.2 KW for the case without helical field) and to be full automatic sequence of operation. (author)

Exponential power spectra, deterministic chaos and Lorentzian pulses in plasma edge dynamics

International Nuclear Information System (INIS)

Maggs, J E; Morales, G J

2012-01-01

Exponential spectra have been observed in the edges of tokamaks, stellarators, helical devices and linear machines. The observation of exponential power spectra is significant because such a spectral character has been closely associated with the phenomenon of deterministic chaos by the nonlinear dynamics community. The proximate cause of exponential power spectra in both magnetized plasma edges and nonlinear dynamics models is the occurrence of Lorentzian pulses in the time signals of fluctuations. Lorentzian pulses are produced by chaotic behavior in the separatrix regions of plasma E × B flow fields or the limit cycle regions of nonlinear models. Chaotic advection, driven by the potential fields of drift waves in plasmas, results in transport. The observation of exponential power spectra and Lorentzian pulses suggests that fluctuations and transport at the edge of magnetized plasmas arise from deterministic, rather than stochastic, dynamics. (paper)

Overcoming Challenges in Kinetic Modeling of Magnetized Plasmas and Vacuum Electronic Devices

Science.gov (United States)

Omelchenko, Yuri; Na, Dong-Yeop; Teixeira, Fernando

2017-10-01

We transform the state-of-the art of plasma modeling by taking advantage of novel computational techniques for fast and robust integration of multiscale hybrid (full particle ions, fluid electrons, no displacement current) and full-PIC models. These models are implemented in 3D HYPERS and axisymmetric full-PIC CONPIC codes. HYPERS is a massively parallel, asynchronous code. The HYPERS solver does not step fields and particles synchronously in time but instead executes local variable updates (events) at their self-adaptive rates while preserving fundamental conservation laws. The charge-conserving CONPIC code has a matrix-free explicit finite-element (FE) solver based on a sparse-approximate inverse (SPAI) algorithm. This explicit solver approximates the inverse FE system matrix (``mass'' matrix) using successive sparsity pattern orders of the original matrix. It does not reduce the set of Maxwell's equations to a vector-wave (curl-curl) equation of second order but instead utilizes the standard coupled first-order Maxwell's system. We discuss the ability of our codes to accurately and efficiently account for multiscale physical phenomena in 3D magnetized space and laboratory plasmas and axisymmetric vacuum electronic devices.

Measurements of the vacuum-plasma response in EXTRAP T2R using generic closed-loop subspace system identification

Energy Technology Data Exchange (ETDEWEB)

Olofsson, K. Erik J., E-mail: erik.olofsson@ee.kth.se [School of Electrical Engineering (EES), Royal Institute of Technology (KTH), Stockholm (Sweden); Brunsell, Per R.; Drake, James R. [School of Electrical Engineering (EES), Royal Institute of Technology (KTH), Stockholm (Sweden)

2012-12-15

Highlights: Black-Right-Pointing-Pointer Unstable plasma response safely measured using special signal processing techniques. Black-Right-Pointing-Pointer Prediction-capable MIMO models obtained. Black-Right-Pointing-Pointer Computational statistics employed to show physical content of these models. Black-Right-Pointing-Pointer Multifold cross-validation applied for the supervised learning problem. - Abstract: A multibatch formulation of a multi-input multi-output closed-loop subspace system identification method is employed for the purpose of obtaining control-relevant models of the vacuum-plasma response in the magnetic confinement fusion experiment EXTRAP T2R. The accuracy of the estimate of the plant dynamics is estimated by computing bootstrap replication statistics of the dataset. It is seen that the thus identified models exhibit both predictive capabilities and physical spectral properties.

Manufacturing method for parts opposed to plasmas and manufacturing device therefor

International Nuclear Information System (INIS)

Fuse, Toshiaki; Tachikawa, Nobuo.

1995-01-01

The present invention provides a method of and a device for manufacturing heat insulation parts which are opposed to plasmas, such as parts in the inside of a thermonuclear reactor, which less suffer from defects such as crackings and peelings in the vicinity of the joining portion of the parts. Namely, when an armour and a heat sink are cooled to a room temperature after joining them, the upper surface of the armour and the bottom of the heat sink are pressurized. Then after restricting the convex deformation at the upper surface of the armour and the concave deformation at the bottom of the heat sink, the heat sink bottom are extended at from 600degC to a room temperature or at a room temperature. When a heat resistant material with a small heat expansion coefficient is joined with a cooling material with a large heat expansion coefficient and then cooled, deformation and residual stresses are generated by the difference of the shrinking amount. But deformation and the residual stresses can be reduced by gradually cooling them while restricting them by using a joining device compared with a case of not restricting them. As a result, occurrence of crackings and peelings in the vicinity of the joining portion can be prevented. (I.S.)

Occurrence of high-beta superthermal plasma events in the close environment of Jupiter's bow shock as observed by Ulysses

International Nuclear Information System (INIS)

Marhavilas, P. K.; Sarris, E. T.; Anagnostopoulos, G. C.

2011-01-01

The ratio of the plasma pressure to the magnetic field pressure (or of their energy densities) which is known as the plasma parameter 'beta'(β) has important implications to the propagation of energetic particles and the interaction of the solar wind with planetary magnetospheres. Although in the scientific literature the contribution of the superthermal particles to the plasma pressure is generally assumed negligible, we deduced, by analyzing energetic particles and magnetic field measurements recorded by the Ulysses spacecraft, that in a series of events, the energy density contained in the superthermal tail of the particle distribution is comparable to or even higher than the energy density of the magnetic field, creating conditions of high-beta plasma. More explicitly, in this paper we analyze Ulysses/HI-SCALE measurements of the energy density ratio (parameter β ep ) of the energetic ions'(20 keV to ∼5 MeV) to the magnetic field's in order to find occurrences of high-beta (β ep >1) superthermal plasma conditions in the environment of the Jovian magnetosphere, which is an interesting plasma laboratory and an important source of emissions in our solar system. In particular, we examine high-beta ion events close to Jupiter's bow shock, which are produced by two processes: (a) bow shock ion acceleration and (b) ion leakage from the magnetosphere.

Particle and power balances of hot-filament discharge plasmas in a multi-dipole device in the presence of a positively biased electrode

International Nuclear Information System (INIS)

Cho, M.H.; Hershkowitz, N.; Intrator, T.

1989-01-01

The plasma potential is typically assumed to float above an anode potential by a few times of an electron temperature (T /e). The difference between the plasma potential and the anode potential can be estimated by considering the particle production and loss. However, it has been reported experimentally that the plasma potential of a steady state plasma can be more negative than the anode potential with a potential dip (-- T /e) in front of the anode. This paper describes particle and power balances to estimate the bulk plasma potential of a hot-filament discharge plasma produced in a multi-dipole plasma device. The bulk plasma potential dependence on positive DC bias applied to an anode is analyzed, and the predicted characteristics of the plasma potential dependence are compared to the experiment. A steady state potential dip in front of an anode is experimentally observed using emissive probes with the zero emission inflection point method, and the conditions for the potential dip formation are derived

A condition closely mimicking IgG4-related disease despite the absence of serum IgG4 elevation and IgG4-positive plasma cell infiltration.

Science.gov (United States)

Hara, Satoshi; Kawano, Mitsuhiro; Mizushima, Ichiro; Yamada, Kazunori; Fujita, Kentaro; Harada, Kenichi; Matsumura, Masami; Yamagishi, Masakazu; Sato, Yasuharu; Yamaguchi, Yutaka; Nakanuma, Yasuni; Nagata, Michio

2016-09-01

We describe a 74-year-old Japanese man with systemic fibroinflammatory conditions closely resembling those of immunoglobulin G4-related disease (IgG4-RD). Radiology and histology showed characteristics of IgG4-related tubulointerstitial nephritis, despite normal serum IgG4 value and scanty IgG4-positive plasma cell infiltration in each organ. This case suggests that a condition closely mimicking IgG4-RD may develop without IgG4-positive plasma cells and those exceptional cases should also be taken into account in the differential diagnosis of IgG4-RD.

Magnetic Fusion Energy Plasma Interactive and High Heat Flux Components: Volume 5, Technical assessment of critical issues in the steady state operation of fusion confinement devices

Energy Technology Data Exchange (ETDEWEB)

1988-01-01

Critical issues for the steady state operation of plasma confinement devices exist in both the physics and technology fields of fusion research. Due to the wide range and number of these issues, this technical assessment has focused on the crucial issues associated with the plasma physics and the plasma interactive components. The document provides information on the problem areas that affect the design and operation of a steady state ETR or ITER type confinement device. It discusses both tokamaks and alternative concepts, and provides a survey of existing and planned confinement machines and laboratory facilities that can address the identified issues. A universal definition of steady state operation is difficult to obtain. From a physics point of view, steady state is generally achieved when the time derivatives approach zero and the operation time greatly exceeds the characteristic time constants of the device. Steady state operation for materials depends on whether thermal stress, creep, fatigue, radiation damage, or power removal are being discussed. For erosion issues, the fluence and availability of the machine for continuous operation are important, assuming that transient events such as disruptions do not limit the component lifetimes. The panel suggests, in general terms, that steady state requires plasma operation from 100 to 1000 seconds and an availability of more than a few percent, which is similar to the expectations for an ETR type device. The assessment of critical issues for steady state operation is divided into four sections: physics issues; technology issues; issues in alternative concepts; and devices and laboratory facilities that can address these problems.

Magnetic Fusion Energy Plasma Interactive and High Heat Flux Components: Volume 5, Technical assessment of critical issues in the steady state operation of fusion confinement devices

International Nuclear Information System (INIS)

1988-01-01

Critical issues for the steady state operation of plasma confinement devices exist in both the physics and technology fields of fusion research. Due to the wide range and number of these issues, this technical assessment has focused on the crucial issues associated with the plasma physics and the plasma interactive components. The document provides information on the problem areas that affect the design and operation of a steady state ETR or ITER type confinement device. It discusses both tokamaks and alternative concepts, and provides a survey of existing and planned confinement machines and laboratory facilities that can address the identified issues. A universal definition of steady state operation is difficult to obtain. From a physics point of view, steady state is generally achieved when the time derivatives approach zero and the operation time greatly exceeds the characteristic time constants of the device. Steady state operation for materials depends on whether thermal stress, creep, fatigue, radiation damage, or power removal are being discussed. For erosion issues, the fluence and availability of the machine for continuous operation are important, assuming that transient events such as disruptions do not limit the component lifetimes. The panel suggests, in general terms, that steady state requires plasma operation from 100 to 1000 seconds and an availability of more than a few percent, which is similar to the expectations for an ETR type device. The assessment of critical issues for steady state operation is divided into four sections: physics issues; technology issues; issues in alternative concepts; and devices and laboratory facilities that can address these problems

Closed cycle device

International Nuclear Information System (INIS)

Ruby, L.E.; Witt, D.L.; Staley, C.F.

1975-01-01

A gas dynamic laser wherein the lasing fluid is recirculated in a closed loop is described. The flow can be assumed to start with the lasing gas passing through a cascade of supersonic nozzles. This low pressure, high velocity gas is then passed through a lasing cavity where the lasing action takes place. The energy of the high velocity gas stream is converted back to static pressure in a supersonic diffuser. The diffuser is constructed with (1) variable geometry, and (2) provisions for bleeding off the boundary layer for improved efficiency. Downstream of the supersonic diffuser there is a heat exchanger which partially cools the gas in the loop. This partially cooled gas is then supplied to a compressor where the pressure and temperature are raised back to the level at the start of the flow. The lasing gas is directed from the exit of the compressor to a manifold upstream of the cascade of supersonic nozzles. The compressor only supplies a pressure rise equal to the pressure loss by inefficiencies in the nozzle, the supersonic diffuser and the pressure drop in the heatexchanger and plumbing. To provide for cooling of the compressor, the gas bled from the diffuser is cooled by a second heat exchanger and pumped back to compressor inlet pressure and introduced into the compressor for cooling. In steady state operation, both heat exchangers referred to above, are designed to regulatethe nozzle inlet gas temperature by removing the amount of heat energy added by compressing minus the amount of energy extracted in the lasing beam and energy lost to the environment. The compressor and pumping means for cooling the compressor can be driven by any means desired. (U.S.)

Plasma-based EUV light source

Science.gov (United States)

Shumlak, Uri; Golingo, Raymond; Nelson, Brian A.

2010-11-02

Various mechanisms are provided relating to plasma-based light source that may be used for lithography as well as other applications. For example, a device is disclosed for producing extreme ultraviolet (EUV) light based on a sheared plasma flow. The device can produce a plasma pinch that can last several orders of magnitude longer than what is typically sustained in a Z-pinch, thus enabling the device to provide more power output than what has been hitherto predicted in theory or attained in practice. Such power output may be used in a lithography system for manufacturing integrated circuits, enabling the use of EUV wavelengths on the order of about 13.5 nm. Lastly, the process of manufacturing such a plasma pinch is discussed, where the process includes providing a sheared flow of plasma in order to stabilize it for long periods of time.

Development of the plasma operational regime in the large helical device by the various wall conditioning methods

International Nuclear Information System (INIS)

Nishimura, K.; Ashikawa, N.; Masuzaki, S.; Miyazawa, J.; Sagara, A.; Goto, M.; Peterson, B.J.; Komori, A.; Noda, N.; Ida, K.; Kaneko, O.; Kawahata, K.; Kobuchi, T.; Kubo, S.; Morita, S.; Osakabe, M.; Sakakibara, S.; Sakamoto, R.; Sato, K.; Shimozuma, T.; Takeiri, Y.; Tanaka, K.; Motojima, O.

2005-01-01

Experiments in the large helical device have been developing since the first discharge in 1998. Baking at 95 deg C, electron cyclotron resonance discharge cleaning, glow discharge cleaning, titanium gettering and boronization were attempted for wall conditioning. Using these conditioning techniques, the partial pressures of the oxidized gases, such as H 2 O, CO and CO 2 , were reduced gradually and the plasma operational regime enlarged. The glow discharge cleaning with the various working gases, such as hydrogen, helium, neon and argon, was effective in increasing the plasma purity. By this method, we obtained a central ion temperature of 10 keV. Boronization, which was started from FY2001, was also effective in reducing the radiation losses from impurities and in enlarging the density operational regime. We obtained a plasma stored energy of 1.31 MJ and an electron density of 2.4 x 10 20 m -3

Low Damage, High Anisotropy Inductively Coupled Plasma for Gallium Nitride based Devices

KAUST Repository

Ibrahim, Youssef H.

2013-05-27

Group III-nitride semiconductors possess unique properties, which make them versatile materials for suiting many applications. Structuring vertical and exceptionally smooth GaN profiles is crucial for efficient optical device operation. The processing requirements for laser devices and ridge waveguides are stringent as compared to LEDs and other electronic devices. Due to the strong bonding and chemically inert nature of GaN, dry etching becomes a critical fabrication step. The surface morphology and facet etch angle are analyzed using SEM and AFM measurements. The influence of different mask materials is also studied including Ni as well as a SiO2 and resist bilayer. The high selectivity Ni Mask is found to produce high sidewall angles ~79°. Processing parameters are optimized for both the mask material and GaN in order to achieve a highly anisotropic, smooth profile, without resorting to additional surface treatment steps. An optimizing a SF6/O2 plasma etch process resulted in smooth SiO2 mask sidewalls. The etch rate and GaN surface roughness dependence on the RF power was also examined. Under a low 2mTorr pressure, the RF and ICP power were optimized to 150W and 300W respectively, such that a smooth GaN morphology and sidewalls was achieved with reduced ion damage. The The AFM measurements of the etched GaN surface indicate a low RMS roughness ranging from 4.75 nm to 7.66 nm.

Fundamental processes of plasma and reactive gas surface treatment for the recovery of hydrogen isotopes from carbon co-deposits in fusion devices

International Nuclear Information System (INIS)

Moeller, Soeren

2014-01-01

The use of carbon-based plasma-facing wall components offers many advantages for plasma operation in magnetic confinement nuclear fusion devices. However, through reactions with the hydrogen based fusion plasma, carbon forms amorphous hydrogenated carbon co-deposits (a-C:H) in the vacuum vessels. If tritium is used to fuel the reactor, this co-deposition can quickly lead to an inacceptable high tritium inventory. Through co-deposition with carbon about 10% of the tritium injected into the reactor can be trapped. Even with other wall materials co-deposition can be significant. A method to recover the hydrogen isotopes from the co-deposits is necessary. The method has to be compatible with the requirements of the devices and nuclear fusion plasma operation. In this work thermo-chemical removal by neutral gases (TCR) and removal by plasmas is investigated. Models are developed to describe the involved processes of both removal methods. TCR is described using a reaction-diffusion model. Within this model the reactive gas diffuses into the co-deposits and subsequently reacts in a thermally activated process. The co-deposits are pyrolysed, forming volatile gases, e.g. CO 2 and H 2 O. These gases are pumped from the vacuum vessel and recycled. Applying the model to literature observations enables to connect data on exposure temperature, pressure, time and co-deposit properties. Two limits of TCR (reaction- or diffusion-limited) are identified. Plasma removal sputters co-deposits by their chemical and physical interaction with the impinging ions. The description uses a 0D plasma model from the literature which derives plasma parameters from the balance of input power to plasma power losses. The model is extended with descriptions of the plasma sheath and ion-surface interactions to derive the co-deposit removal rates. Plasma removal can be limited by this ion induced surface release rate or the rate of pumping of the released species. To test the models dedicated

Fundamental processes of plasma and reactive gas surface treatment for the recovery of hydrogen isotopes from carbon co-deposits in fusion devices

Energy Technology Data Exchange (ETDEWEB)

Moeller, Soeren

2014-11-01

The use of carbon-based plasma-facing wall components offers many advantages for plasma operation in magnetic confinement nuclear fusion devices. However, through reactions with the hydrogen based fusion plasma, carbon forms amorphous hydrogenated carbon co-deposits (a-C:H) in the vacuum vessels. If tritium is used to fuel the reactor, this co-deposition can quickly lead to an inacceptable high tritium inventory. Through co-deposition with carbon about 10% of the tritium injected into the reactor can be trapped. Even with other wall materials co-deposition can be significant. A method to recover the hydrogen isotopes from the co-deposits is necessary. The method has to be compatible with the requirements of the devices and nuclear fusion plasma operation. In this work thermo-chemical removal by neutral gases (TCR) and removal by plasmas is investigated. Models are developed to describe the involved processes of both removal methods. TCR is described using a reaction-diffusion model. Within this model the reactive gas diffuses into the co-deposits and subsequently reacts in a thermally activated process. The co-deposits are pyrolysed, forming volatile gases, e.g. CO{sub 2} and H{sub 2}O. These gases are pumped from the vacuum vessel and recycled. Applying the model to literature observations enables to connect data on exposure temperature, pressure, time and co-deposit properties. Two limits of TCR (reaction- or diffusion-limited) are identified. Plasma removal sputters co-deposits by their chemical and physical interaction with the impinging ions. The description uses a 0D plasma model from the literature which derives plasma parameters from the balance of input power to plasma power losses. The model is extended with descriptions of the plasma sheath and ion-surface interactions to derive the co-deposit removal rates. Plasma removal can be limited by this ion induced surface release rate or the rate of pumping of the released species. To test the models dedicated

An approach to next step device optimisation

International Nuclear Information System (INIS)

Salpietro, E.

2000-01-01

The requirements for ITER EDA were to achieve ignition with a good safety margin, and controlled long inductive burn. These requirements lead to a big device, which requested a too ambitious step to be undertaken by the world fusion community. More realistic objectives for a next step device shall be to demonstrate the net production of energy with a high energy gain factor (Q) and a high boot strap current fraction (>60%) which is required for a Fusion Power Plant (FPP). The Next Step Device (NSD) shall also allow operation flexibility in order to explore a large range of plasma parameters to find out the optimum concept for the fusion power plant prototype. These requirements could be too demanding for one single device and could probably be better explored in a strongly integrated world programme. The cost of one or more devices is the decisive factor for the choice of the fusion power development programme strategy. The plasma elongation and triangularity have a strong impact in the cost of the device and are limited by the plasma vertical position control issue. The distance between plasma separatrix and the toroidal field conductor does not vary a lot between devices. It is determined by the sum of the distance between first wall-plasma sepratrix and the thickness of the nuclear shield required to protect the toroidal field coil insultation. The thickness of the TF coil is determined by the allowable stresses and superconducting characteristics. The outer radius of the central solenoid is the result of an optimisation to provide the magnetic flux to inductively drive the plasma. Therefore, in order to achieve the objectives for Q and boot-strap current fractions at the minimum cost, the plasma aspect ratio and magnetic field value shall be determined. The paper will present the critical issues for the next device and will make considerations on the optimal way to proceed towards the realisation of the fusion power plant

Assessment of image quality in x-ray radiography imaging using a small plasma focus device

International Nuclear Information System (INIS)

Kanani, A.; Shirani, B.; Jabbari, I.; Mokhtari, J.

2014-01-01

This paper offers a comprehensive investigation of image quality parameters for a small plasma focus as a pulsed hard x-ray source for radiography applications. A set of images were captured from some metal objects and electronic circuits using a low energy plasma focus at different voltages of capacitor bank and different pressures of argon gas. The x-ray source focal spot of this device was obtained to be about 0.6 mm using the penumbra imaging method. The image quality was studied by several parameters such as image contrast, line spread function (LSF) and modulation transfer function (MTF). Results showed that the contrast changes by variations in gas pressure. The best contrast was obtained at a pressure of 0.5 mbar and 3.75 kJ stored energy. The results of x-ray dose from the device showed that about 0.6 mGy is sufficient to obtain acceptable images on the film. The measurements of LSF and MTF parameters were carried out by means of a thin stainless steel wire 0.8 mm in diameter and the cut-off frequency was obtained to be about 1.5 cycles/mm. - Highlights: • We investigated a small plasma focus as pulsed x-ray source for radiography applications. • The image quality was studied by several parameters such as image contrast, LSF and MTF. • The x-ray source focal spot was obtained to be ∼0.6 mm using the penumbra imaging method. • The x-ray dose measurement showed that about 0.6 mGy is sufficient to obtain acceptable images on the film. • The profiles of LSF and MTF showed that the cut-off frequency is about 1.5 cycles/mm

A two photon absorption laser induced fluorescence diagnostic for fusion plasmas

Energy Technology Data Exchange (ETDEWEB)

Magee, R. M.; Galante, M. E.; McCarren, D.; Scime, E. E. [Physics Department, West Virginia University, Morgantown, West Virginia 26506 (United States); Boivin, R. L.; Brooks, N. H.; Groebner, R. J.; Hill, D. N. [General Atomics, San Diego, California 92121 (United States); Porter, G. D. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2012-10-15

The quality of plasma produced in a magnetic confinement fusion device is influenced to a large extent by the neutral gas surrounding the plasma. The plasma is fueled by the ionization of neutrals, and charge exchange interactions between edge neutrals and plasma ions are a sink of energy and momentum. Here we describe a diagnostic capable of measuring the spatial distribution of neutral gas in a magnetically confined fusion plasma. A high intensity (5 MW/cm{sup 2}), narrow bandwidth (0.1 cm{sup -1}) laser is injected into a hydrogen plasma to excite the Lyman {beta} transition via the simultaneous absorption of two 205 nm photons. The absorption rate, determined by measurement of subsequent Balmer {alpha} emission, is proportional to the number of particles with a given velocity. Calibration is performed in situ by filling the chamber to a known pressure of neutral krypton and exciting a transition close in wavelength to that used in hydrogen. We present details of the calibration procedure, including a technique for identifying saturation broadening, measurements of the neutral density profile in a hydrogen helicon plasma, and discuss the application of the diagnostic to plasmas in the DIII-D tokamak.

A two photon absorption laser induced fluorescence diagnostic for fusion plasmas.

Science.gov (United States)

Magee, R M; Galante, M E; McCarren, D; Scime, E E; Boivin, R L; Brooks, N H; Groebner, R J; Hill, D N; Porter, G D

2012-10-01

The quality of plasma produced in a magnetic confinement fusion device is influenced to a large extent by the neutral gas surrounding the plasma. The plasma is fueled by the ionization of neutrals, and charge exchange interactions between edge neutrals and plasma ions are a sink of energy and momentum. Here we describe a diagnostic capable of measuring the spatial distribution of neutral gas in a magnetically confined fusion plasma. A high intensity (5 MW/cm(2)), narrow bandwidth (0.1 cm(-1)) laser is injected into a hydrogen plasma to excite the Lyman β transition via the simultaneous absorption of two 205 nm photons. The absorption rate, determined by measurement of subsequent Balmer α emission, is proportional to the number of particles with a given velocity. Calibration is performed in situ by filling the chamber to a known pressure of neutral krypton and exciting a transition close in wavelength to that used in hydrogen. We present details of the calibration procedure, including a technique for identifying saturation broadening, measurements of the neutral density profile in a hydrogen helicon plasma, and discuss the application of the diagnostic to plasmas in the DIII-D tokamak.

Department of Plasma Physics and Technology: Overview

International Nuclear Information System (INIS)

Sadowski, M.

1998-01-01

(full text) In 1997, theoretical studies mainly concerned the verification of physical models on the basis of experimental data, an analysis of plasma behaviour within regions close to electrode surfaces during quasi-continuous discharges induced by microwaves , as well as modelling of a discharge development within coaxial plasma injectors. Another direction of theoretical studies concerned elementary processes of importance for plasma research, and in particular those taking into consideration the role of spin within a classical model of proton - hydrogen atom collisions. Experimental studies comprised measurements of pulsed electron beams and effects of the polarization of X-rays emitted from Plasma Focus (PF) facilities, research on emission characteristics of different PF devices, as well as measurements of pulsed electron and ion-beams emitted from various devices of the PF and Z-Pinch type. An important direction of experimental studies concerned X-ray and ion measurements at a large PF-1000 facility. In the field of plasma diagnostics, efforts were devoted to an analysis of the results obtained from time-resolved measurements of nitrogen ions and deuterons within PF-type devices. Within a frame of diagnostics, a substantial achievement was also the design and construction of a new measuring equipment for studies of plasma dynamics and X-ray emissions. Particular attention was also paid to studies connected with the calibration of various solid-state nuclear track detectors (NTDs), particularly modern plastic detectors of the CR-39, PM-355 and PM-500 type. Studies in the field of fusion technology concerned the design and construction of a special pulse generator for the simulation of electromagnetic interference, as well as other efforts connected with research on electromagnetic compatibility of electronic and electrotechnical devices. Research on new types of HV pulse generators were carried out partially under contracts with industrial laboratories. In

New modular heliotron system compatible with closed helical divertor and good plasma confinement

International Nuclear Information System (INIS)

Yamazaki, K.; Watanabe, K.Y.

1995-01-01

A new helical system ('modular heliotron') with improved modular coils compatible with an efficient closed helical divertor and a good plasma confinement property is proposed, based on a heliotron system with continuous helical coils and one pair of poloidal coils. The physics optimization of this system as a function of the gap angle between adjacent modular coils has been carried out by means of vacuum magnetic surface calculations and finite-beta plasma analyses, and a new improved coil system is invented by combining sectored helical field coils with sectored returning poloidal field coils. A modular heliotron with standard coil winding law (the reference modular heliotron) was previously proposed, but it is found that this was not appropriate to keep a clean helical divertor and high beta configuration when the coil gap becomes large. By modulating the modular coil winding with outside-plus and inside-minus pitch modulation, almost the same good magnetic configuration as that of a conventional heliotron can be produced. The optimal gap angle is determined as a function of the modulation parameter. This improved modular heliotron permits a larger gap angle between adjacent modules and produces a cleaner helical divertor configuration than the reference modular heliotron. All these helical systems are created by only modular coils without poloidal coils. (author). Letter-to-the-editor. 11 refs, 7 figs

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.

A 5 kA pulsed power supply for inductive and plasma loads in large volume plasma device

Energy Technology Data Exchange (ETDEWEB)

Srivastava, P. K., E-mail: pkumar@ipr.res.in; Singh, S. K.; Sanyasi, A. K.; Awasthi, L. M., E-mail: kushagra.lalit@gmail.com; Mattoo, S. K. [Institute for Plasma Research, Gandhinagar (India)

2016-07-15

This paper describes 5 kA, 12 ms pulsed power supply for inductive load of Electron Energy Filter (EEF) in large volume plasma device. The power supply is based upon the principle of rapid sourcing of energy from the capacitor bank (2.8 F/200 V) by using a static switch, comprising of ten Insulated Gate Bipolar Transistors (IGBTs). A suitable mechanism is developed to ensure equal sharing of current and uniform power distribution during the operation of these IGBTs. Safe commutation of power to the EEF is ensured by the proper optimization of its components and by the introduction of over voltage protection (>6 kV) using an indigenously designed snubber circuit. Various time sequences relevant to different actions of power supply, viz., pulse width control and repetition rate, are realized through optically isolated computer controlled interface.

Toward High-Performance Coatings for Biomedical Devices: Study on Plasma-Deposited Fluorocarbon Films and Ageing in PBS

Directory of Open Access Journals (Sweden)

Diego Mantovani

2010-03-01

Full Text Available High performance coatings tailored to medical devices represent a recognised approach to modulate surface properties. Plasma-deposited fluorocarbon films have been proposed as a potential stent coating. Previous studies have shown promising adhesion properties: the 35 nm-thick film sustained plastic deformation up to 25% such as induced during the clinical implantation. In this study, the compositional and morphological changes of plasma-deposited fluorocarbon films were examined during ageing in a pseudo-physiological medium, a phosphate buffer solution (PBS, by angle-resolved XPS, FT-IR data and AFM images. The evolution of the ageing process is discussed: defluorination and crosslinking yielded an oxidized protective top layer onto the films, which showed further degradation.

40 CFR 63.1034 - Closed vent systems and control devices; or emissions routed to a fuel gas system or process...

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Closed vent systems and control devices; or emissions routed to a fuel gas system or process standards. 63.1034 Section 63.1034 Protection... routed to a fuel gas system or process standards. (a) Compliance schedule. The owner or operator shall...

Collisional avalanche exponentiation of run-away electrons in electrified plasmas

International Nuclear Information System (INIS)

Jayakumar, R.; Fleischmann, H.H.; Zweben, S.J.; Cornell Univ., Ithaca, NY

1992-07-01

In contrast to earlier expectations, it is estimated that generation of runaway electrons from close collisions of existing runaways with cold plasma electrons can be significant even for small electric fields, whenever runaways can gain energies of about 20 MeV or more. In that case, the runaway population will grow exponentially with the energy spectrum showing an exponential decrease towards higher energies.Energy gains of the required magnitude may occur in large Tokamak devices as well as in cosmic-ray generation

Dust in flowing magnetized plasma

International Nuclear Information System (INIS)

Pandey, Birendra P.; Samarian, Alex A.; Vladimirov, Sergey V.

2009-01-01

Plasma flows occur in almost every laboratory device and interactions of flowing plasmas with near-wall impurities and/or dust significantly affects the efficiency and lifetime of such devices. The charged dust inside the magnetized flowing plasma moves primarily under the influence of the plasma drag and electric forces. Here, the charge on the dust, plasma potential, and plasma density are calculated self-consistently. The electrons are assumed non-Boltzmannian and the effect of electron magnetization and electron-atom collisions on the dust charge is calculated in a self-consistent fashion. For various plasma magnetization parameters viz. the ratio of the electron and ion cyclotron frequencies to their respective collision frequencies, plasma-atom and ionization frequencies, the evolution of the plasma potential and density in the flow region is investigated. The variation of the dust charge profile is shown to be a sensitive function of plasma parameters. (author)

Method and means of reducing erosion of components of plasma devices exposed to helium and hydrogen isotope radiation

International Nuclear Information System (INIS)

Kaminsky, M.S.; Das, S.K.; Rossing, T.D.

1977-01-01

Surfaces of components of plasma devices exposed to radiation by atoms or ions of helium or isotopes of hydrogen can be protected from damage due to blistering by shielding the surfaces with a structure formed by sintering a powder of aluminum or beryllium and its oxide or by coating the surfaces with such a sintered metal powder. 7 claims

Deposition of Al N and Ti N thin films on substrates of stainless steel SS304 using plasma focus device

International Nuclear Information System (INIS)

Al-Hawat, Sh.; Soukieh, M.; Abou Kharoub, M.; Al-Sadat, W.

2006-06-01

A 2.8 kJ plasma focus device was used to deposit thin films of aluminium nitride Al N and titanium nitride Ti N on a stainless steel 394 substrate, in order to improve its surface properties. The deposition process was carried out using various number of nitrogen plasma shots at pressures 0.5-0.75 mbar and at different sample's distances from the anode. The plasma diagnostics was achieved using the voltage and current signals recorded by a voltage divider and Rogovskii coil to determine the temperature and plasma density. The surface hardness of SS-304 was increased by about 50% after plasma coating and the thickness of the coated layers was about 1-2μm. This study shows that the hardness is increased with increasing the number of shots and decreased with the distance from the anode. The coated layers were characterized and a qualitative understanding of the deposition process was given. (author)

Statistical properties of edge plasma turbulence in the Large Helical Device

Science.gov (United States)

Dewhurst, J. M.; Hnat, B.; Ohno, N.; Dendy, R. O.; Masuzaki, S.; Morisaki, T.; Komori, A.

2008-09-01

Ion saturation current (Isat) measurements made by three tips of a Langmuir probe array in the Large Helical Device are analysed for two plasma discharges. Absolute moment analysis is used to quantify properties on different temporal scales of the measured signals, which are bursty and intermittent. Strong coherent modes in some datasets are found to distort this analysis and are consequently removed from the time series by applying bandstop filters. Absolute moment analysis of the filtered data reveals two regions of power-law scaling, with the temporal scale τ ≈ 40 µs separating the two regimes. A comparison is made with similar results from the Mega-Amp Spherical Tokamak. The probability density function is studied and a monotonic relationship between connection length and skewness is found. Conditional averaging is used to characterize the average temporal shape of the largest intermittent bursts.

Augmentation and Control of Burn Rates in Plasma Devices

National Research Council Canada - National Science Library

Bourham, Mohamed

1999-01-01

Interaction of electrothermal plasmas with solid propellants necessitates thorough understanding of plasma-propellant interface physics, momentum and energy transfer, plasma flow regimes, and mixing processes...

Limits of deuterium pressure range with neutron production in plasma focus devices

International Nuclear Information System (INIS)

Pouzo, J.; Milanese, M.; Piriz, R.; Cortazar, D.; Moroso, R.

1988-01-01

In this work we present the experimental curves of neutron yield (Y) respect to the deuterium filling pressure (p) obtained in our plasma focuses device PACO. Y increases with the focus current (I f ) according with the scaling law Y ∼I 4-5 f , but it presents a limited range of p beyond which Y drastically decreases. The higher pressure limit is coincident with recently reported limit due to the energy available to maintain the ionization rate of the neutral gas during the roll-off stage. The lower pressure limit is here explained, through experimental evidences, in terms of a phenomenon connected with the dynamics of the current sheath (cs) during the roll-off stage. (author). 8 refs, 11 figs

Deposition and surface characterization of nanoparticles of zinc oxide using dense plasma focus device in nitrogen atmosphere

International Nuclear Information System (INIS)

Malhotra, Yashi; Srivastava, M P; Roy, Savita

2010-01-01

Nanoparticles of zinc oxide from zinc oxide pellets in the nitrogen plasma atmosphere are deposited on n and p type silicon substrates using Dense Plasma Focus device. The hot and dense nitrogen plasma formed during the focus phase ionizes the ZnO pellet, which then move upward in a fountain like shape and gets deposited on substrates which are placed above the top of the anode. Structural and surface properties of the deposited ZnO are investigated using X-ray diffraction and Atomic force microscope (AFM). X-ray spectra shows the diffraction plane (002) of ZnO nanoparticles deposited on Si with few shots in nitrogen atmosphere. AFM investigations revealed that there are nanoparticles of size between 15-80 nm on n-Si and p-Si substrates. The deposition on n-type Si is better than the p-type Si can be seen from AFM images, this may be due to different orientation of silicon.

Cold atoms close to surfaces

DEFF Research Database (Denmark)

Krüger, Peter; Wildermuth, Stephan; Hofferberth, Sebastian

2005-01-01

Microscopic atom optical devices integrated on atom chips allow to precisely control and manipulate ultra-cold (T atoms and Bose-Einstein condensates (BECs) close to surfaces. The relevant energy scale of a BEC is extremely small (down to ... be utilized as a sensor for variations of the potential energy of the atoms close to the surface. Here we describe how to use trapped atoms as a measurement device and analyze the performance and flexibility of the field sensor. We demonstrate microscopic magnetic imaging with simultaneous high spatial...

Magnetic field coil in nuclear fusion device

International Nuclear Information System (INIS)

Yamaguchi, Mitsugi; Takano, Hirohisa.

1975-01-01

Object: To provide an electrical-insulatively stabilized magnetic field coil in nuclear fusion device, restraining an increase in voltage when plasma current is rapidly changed. Structure: A magnetic field coil comprises coils arranged coaxial with respective vacuum vessels, said coils being wound in positive and reverse polarities so as to form a vertical magnetic field within the plasma. The coils of the positive polarity are arranged along the vacuum vessel inside of an axis vertical in section of the annular plasma and are arranged symmetrically up and down of a horizontal axis. On the other hand, the coils of the reverse polarity are arranged along the vacuum vessel outside of a vertical axis and arranged symmetrically up and down of the horizontal axis. These positive and reverse polarity coils are alternately connected in series, and lead portions of the coils are connected to a power source by means of connecting wires. In this case, lead positions of the coils are arranged in one direction, and the connecting wires are disposed in closely contact relation to offset magnetic fields formed by the connecting wires each other. (Kawakami, Y.)

Integrated Prediction and Mitigation Methods of Materials Damage and Lifetime Assessment during Plasma Operation and Various Instabilities in Fusion Devices

Energy Technology Data Exchange (ETDEWEB)

Hassanein, Ahmed [Purdue Univ., West Lafayette, IN (United States)

2015-03-31

This report describes implementation of comprehensive and integrated models to evaluate plasma material interactions during normal and abnormal plasma operations. The models in full3D simulations represent state-of-the art worldwide development with numerous benchmarking of various tokamak devices and plasma simulators. In addition, significant number of experimental work has been performed in our center for materials under extreme environment (CMUXE) at Purdue to benchmark the effect of intense particle and heat fluxes on plasma-facing components. This represents one-year worth of work and resulted in more than 23 Journal Publications and numerous conferences presentations. The funding has helped several students to obtain their M.Sc. and Ph.D. degrees and many of them are now faculty members in US and around the world teaching and conducting fusion research. Our work has also been recognized through many awards.

Integrated Prediction and Mitigation Methods of Materials Damage and Lifetime Assessment during Plasma Operation and Various Instabilities in Fusion Devices

International Nuclear Information System (INIS)

Hassanein, Ahmed

2015-01-01

This report describes implementation of comprehensive and integrated models to evaluate plasma material interactions during normal and abnormal plasma operations. The models in full3D simulations represent state-of-the art worldwide development with numerous benchmarking of various tokamak devices and plasma simulators. In addition, significant number of experimental work has been performed in our center for materials under extreme environment (CMUXE) at Purdue to benchmark the effect of intense particle and heat fluxes on plasma-facing components. This represents one-year worth of work and resulted in more than 23 Journal Publications and numerous conferences presentations. The funding has helped several students to obtain their M.Sc. and Ph.D. degrees and many of them are now faculty members in US and around the world teaching and conducting fusion research. Our work has also been recognized through many awards.

Simulation of electrical discharge in a 3.6 Joule miniature plasma focus device using SIMULINK

International Nuclear Information System (INIS)

Jafari, H.; Habibi, M.

2014-01-01

A novel technique has been developed and studied in this paper to simulate the electrical discharge circuit of a 3.6 J miniature plasma focus device (PFD) and investigate the effect of inductance variation on voltage spike and current dip. The technique is based on a correlation between the electrical discharge circuit and plasma dynamics in a very small PFD that operates at the energy of 3.6 J. The simulation inputs include the charging voltage, capacitor bank capacitance, current limiter resistance, bypass resistance as well as the time-dependent inductance and resistance of the plasma sheath which are calculated by assuming the plasma dynamics as transit times in going from one phase to the next. The variations of the most important elements in the circuit (i.e. the constant and breakdown inductances) and their effects on the current dip are studied in PFDs with low and high constant inductance. The model demonstrated for achieving a good pinch in the PFD, although the total inductance of the system should be low; however there is always an optimum inductance which causes an appropriate pinch. Furthermore, the electrical power produced by the pulsed power supply, the mechanical energy as well as the magnetic energy which are transferred into the plasma tube were obtained from simulation. The graph of electrical power demonstrated a high instantaneous increment in the power transferred into the plasma as one of the greatest advantages of the pulsed power supply. The simulation was performed using software tools within the MATLAB/SIMULINK simulation environment. The PFD, generating neutrons in the range of 10 6 to 10 10 neutrons per pulse will have substantial use in the physics and engineering applications. (authors)

Development and Testing of Atomic Beam-Based Plasma Edge Diagnostics in the CIEMAT Fusion Devices

International Nuclear Information System (INIS)

Tafalla, D.; Tabares, F.L.; Ortiz, P.; Herrero, V.J.; Tanarro, I.

1998-01-01

In this report the development of plasma edge diagnostic based on atomic beam techniques fir their application in the CIEMAT fusion devices is described. The characterisation of the beams in laboratory experiments at the CSIC, together with first results in the Torsatron TJ-II are reported. Two types of beam diagnostics have been developed: a thermal (effusive) Li and a supersonic, pulsed He beams. This work has been carried out in collaboration between the institutions mentioned above under partial financial support by EURATOM. (Author) 17 refs

Closed cycle MHD specialist meeting. Progress report, 1971--1972

International Nuclear Information System (INIS)

Rietjens, L.H.

1972-04-01

Abstracts of the conference papers on closed cycle MHD research are presented. The general areas of discussion are the following: results on closed cycle experiments; plasma properties, and instabilities and stabilization in nonequilibrium plasmas; loss mechanisms, current distributions, electrode effects, boundary layers, and gas dynamic effects; and design concepts of large MHD generators, and nuclear MHD power plants. (GRA)

Continuous supersonic plasma wind tunnel

DEFF Research Database (Denmark)

Andersen, S.A.; Jensen, Vagn Orla; Nielsen, P.

1968-01-01

The B field configuration of a Q-device has been modified into a magnetic Laval nozzle. Continuous supersonic plasma flow is observed with M≈3......The B field configuration of a Q-device has been modified into a magnetic Laval nozzle. Continuous supersonic plasma flow is observed with M≈3...

Plasma dynamics in a staged pinch device

International Nuclear Information System (INIS)

Khattak, N.A.D.; Ahmed, Z.; Mirza, A.M.; Murtaza, G.

1998-01-01

Plasma parameters in fiber initiated fast and dense theta-pinch plasma driven by an annular finite-thickness gas-puff Z-pinch are studied. The imploding gas-puff Z-pinch plasma traps an axial magnetic field B/sub z/, compressing it to large values (of the order of several megagauss) in an extremely short time. The rapidly changing magnetic flux of this field induces an azimuthal current on the surface of the coaxially placed fiber, with a rise time an order of magnitude shorter than the applied Z-pinch current. The shorter rise time of the current stabilizes the pinch against sausage mode of MHD instabilities. Our numerical results demonstrate that for a relatively thick gas-puff layer, the compression occurs before the current saturates. At the peak compression the fuel densities of the order of 10/sup 25/ cm/sup -3/ and temperature above 10 keV can be achieved on a time scale of 0.1 nanoseconds, yielding the Lawson Criterion parameters n tau is approximately equal to 10/sup 14/ sec cm/sup -3/ for D-T fuel. The snow-plow effect incorporated in our model exercise a strong influence on the onset and growth rate of sausage and Rayleigh-Taylor (R-T) modes of instabilities. Imposing a rotational velocity on the outer thin gas-puff plasma can control the Rayleigh-Taylor instability. Numerical results indicate that the choice of the spin velocity is critical. Large values of the spin velocity, though provide stabilization against the R-T instability at the final stage of compression, however, it adversely reduce the plasma parameters so essential to achieve controlled fusion. Our analysis, therefore, suggests that a judicious choice of the spin velocity is necessary to obtain the desired temperature and density, especially when we seed D-T fiber plasma with a small fraction of high-Z Kr impurity to initiate the radiative collapse. (author)

Thermonuclear device

International Nuclear Information System (INIS)

Honda, Takuro; Maki, Koichi.

1997-01-01

The present invention provides a thermonuclear device, in which integrity of a measuring device is kept, the reactor wall temperature and wear of armour materials are monitored accurately even under intense radiation rays, so that the flow rate of coolants and plasma power can be controlled by using the signals. Infrared rays generated from the surface of the armour materials disposed on a first wall are detected to measure the reactor wall temperature. Coolant flow rate and plasma power are controlled based on the obtained reactor wall temperature. In addition, infrared rays generated from the back of the armour materials are detected to obtain the surface temperature in order to avoid intense radiation rays from plasmas. The coolant flow rate and the plasma power are controlled based on the obtained temperature on the surface of the reactor thereby controlling the temperature of the first wall and the armour material to 300degC or lower in a case of the first wall made of stainless steel and 1000degC or lower in a case of the armour material made of graphite. (I.S.)

Plasma engineering: a perspective

International Nuclear Information System (INIS)

Gralnick, S.L.

1978-01-01

This review paper will present the authors perspective of the field of Plasma Engineering as it has evolved over the preceding five years. This embrionic discipline has grown in that period of time to the point where it is sufficiently mature to become part of the curriculum, and a speciality within, the discipline of Nuclear Engineering. Plasma Engineering can be distinguished from the underlying science of plasma physics in that in the pursuit of the latter, our goal is the understanding of the fundamental processes governing the behavior of plasmas while the former discipline seeks the embodiment of these concepts in useful devices. Consequent to this goal, the plasma engineer, of necessity, is concerned with the interfaces between a plasma configuration and the device by which it is produced and maintained. These interface problems, often referred to as kitchen physics are multidisciplinary in nature, and their solution requires careful attention to both plasma physics and machine engineering detail

The evolution of magnetic structures due to open-quote open-quote magnetosonic streaming close-quote close-quote

International Nuclear Information System (INIS)

Ryutova, M.P.; Kaisig, M.; Tajima, T.

1996-01-01

The Faraday effect in gasdynamics called acoustic streaming and its accompanying nonlinear phenomena have analogies in plasma magnetohydrodynamics. A natural place where these effects may occur is the solar atmosphere with its strongly inhomogeneous magnetic fields concentrated in random magnetic flux tubes. Unlike acoustic streaming in the usual gasdynamics, nonlinear phenomena consisting in the generation of plasma flows by an oscillating magnetic flux tube, open-quote open-quote magnetosonic streaming close-quote close-quote (Ryutova 1986), is accompanied by a current drive and results in a specific evolution of magnetic structures: depending on the physical parameters of the medium a single magnetic flux tube may be either split into thinner flux tubes or dissolved diffusively into the ambient plasma. The effect of the open-quote open-quote magnetosonic streaming,close-quote close-quote on one hand, is an obvious candidate for the generation of mass flows at magnetic flux tubes sites, and on the other hand, it plays an essential role in the evolution of magnetic structures and ultimately may determine their lifetime. The theory of magnetosonic streaming is general and can be applied to other astrophysical objects that maintain oscillatory motions and contain structured magnetic fields or magnetic domains. We review analytical results and describe the origin of the magnetosonic streaming in magnetic flux tubes due to their interaction with acoustic waves. We study numerically the regime of the open-quote open-quote magnetosonic streaming close-quote close-quote corresponding to splitting of a magnetic flux tube. Our computer simulation supports and extends the analytical result. copyright 1996 The American Astronomical Society

Baking exhaustion device in thermonuclear device

Energy Technology Data Exchange (ETDEWEB)

Kondo, Mitsunori.

1987-02-02

Purpose: To rapidly remove tritium and impurity from the vacuum region in the access port of the baking exhaustion device in a thermonuclear device. Constitution: Each of the gaps at the boundary between a fixed shielding member and a blanket module and at the boundary between the blanket and a divertor is made extremely small so as to minimize the neutron streaming from plasmas. Accordingly, in the case of evacuating the vacuum region in the access port, the gap conductance is extremely poor and the exhaustion speed is low. Then, baking pipeways for flowing high temperature fluids are embedded to the surface layer at the position facing to the vacuum region and the plasma evacuation duct and the vacuum region are connected with an evacuation duct of the access port. By flowing high temperature fluids in the pipeways and conducting evacuation, baking exhaustion can be carried out rapidly. (Kamimura, M.).

Modeling and simulation of plasma materials processing devices

International Nuclear Information System (INIS)

Graves, D.B.

1996-01-01

Plasma processing has emerged as a central technology in the manufacture of integrated circuits (ICs) and related industries. These plasmas are weakly to partially ionized gases, typically operated at a few to several hundred mTorr gas pressure, with neutral temperatures ranging from room temperature to 500 degrees K. Electron mean energies are typically a few eV and ion energies in the bulk plasma are about 0.05-0.5 eV. Positive ions axe accelerated in the sheaths to impact surfaces with energies ranging from about 10 eV to hundreds of eV. These energetic ions profoundly affect rates of surface chemical reactions. One of the consequences of the recent rapid growth in the IC industry has been a greater focus on manufacturing productivity. The capital costs of equipment that is used in manufacturing IC's has become a large fraction of the ∼ $1 billion cost of building a wafer fab. There is now a strong economic incentive to develop workstation-based simulations of plasma chemical reactors in order to design, optimize and control plasma reactors. I will summarize efforts to develop such models, including electromagnetic coupling, and transport and kinetics of charged and neutral species. Length and time scale disparities in the plasma tool challenge current simulation approaches, and I will address strategies to attack aspects of this problem. In addition, I will present some of our recent efforts to exploit molecular dynamics simulations employing empirical potentials to get hints about qualitative mechanisms and ideas on how to formulate rate expressions for plasma-surface chemical processes. Video illustrations of selected sets of ion trajectories impacting near-surface regions of the substrate will be presented

Some dynamical properties of very strong double layers in a triple plasma device

International Nuclear Information System (INIS)

Carpenter, T.; Torven, S.

1987-01-01

Experimental results on three dynamic properties of very strong double layers observed in a triple plasma device are presented. First, it is observed that when an inductance of sufficient size is inserted in series with the external bias supply used to produce the double layer, disruptions in the plasma current occur accompanied by disruptions in the double layer potential. Second, it is observed that with all external reactances reduced as much as possible, a sort of jitter-motion occurs in the position of the double layer around its equilibrium position. Third, when the external bias supply is pulsed, the initial potential distribution is observed to have an essentially uniform slope, as in the case of a vacuum capacitor. The disruption phenomenon may be explained in terms of the behavior of the potential structure as a function of the bias voltage and this explanation is discussed along with the experimental evidence for its validity. A comparable understanding of the other two phenomena has not been achieved, but in both cases there are qualitative difference between the behavior reported here and what has been observed in Q-machines and these difference are discussed. (author)

Prompt loss of beam ions in KSTAR plasmas

Directory of Open Access Journals (Sweden)

Jun Young Kim

2016-10-01

Full Text Available For a toroidal plasma facility to realize fusion energy, researching the transport of fast ions is important not only due to its close relation to the heating and current drive efficiencies but also to determine the heat load on the plasma-facing components. We present a theoretical analysis and orbit simulation for the origin of lost fast-ions during neutral beam injection (NBI heating in Korea Superconducting Tokamak Advanced Research (KSTAR device. We adopted a two-dimensional phase diagram of the toroidal momentum and magnetic moment and describe detectable momentums at the fast-ion loss detector (FILD position as a quadratic line. This simple method was used to model birth ions deposited by NBI and drawn as points in the momentum phase space. A Lorentz orbit code was used to calculate the fast-ion orbits and present the prompt loss characteristics of the KSTAR NBI. The scrape-off layer deposition of fast ions produces a significant prompt loss, and the model and experimental results closely agreed on the pitch-angle range of the NBI prompt loss. Our approach can provide wall load information from the fast ion loss.

Scattering and extinction of ion beams in a dusty plasma device

International Nuclear Information System (INIS)

Nakamura, Y.

2001-01-01

Collisions of ions with charged dust grains are important for the propagation of low frequency waves such as dust acoustic waves and dust ion-acoustic waves. The collision cross-sectional area of charged dust grains depends on the velocity of an ion beam. The collision cross-sectional area of charged dust grains with beam ions is measured. It is compared with the geometrical cross-sectional area of the grain. The experiment is performed in a dusty double-plasma device with glass beads of 8.9 μm in average diameter. The ion beam current and energy are measured with a directional retarding potential analyzer. It is observed that, when dust density inside the system is increased, the beam current ratio is reduced. From the reduction of the ion beam current, the effective cross-sectional area of the dust particle is estimated as a function of the beam energy

Contribution of the different erosion processes to material release from the vessel walls of fusion devices during plasma operation

International Nuclear Information System (INIS)

Behrisch, R.

2002-01-01

In high temperature plasma experiments several processes contribute to erosion and loss of material from the vessel walls. This material may enter the plasma edge and the central plasma where it acts as impurities. It will finally be re-deposited at other wall areas. These erosion processes are: evaporation due to heating of wall areas. At very high power deposition evaporation may become very large, which has been named ''blooming''. Large evaporation and melting at some areas of the vessel wall surface may occur during heat pulses, as observed in plasma devices during plasma disruptions. At tips on the vessel walls and/or hot spots on the plasma exposed solid surfaces electrical arcs between the plasma and the vessel wall may ignite. They cause the release of ions, atoms and small metal droplets, or of carbon dust particles. Finally, atoms from the vessel walls are removed by physical and chemical sputtering caused by the bombardment of the vessel walls with ions as well as energetic neutral hydrogen atoms from the boundary plasma. All these processes have been, and are, observed in today's plasma experiments. Evaporation can in principle be controlled by very effective cooling of the wall tiles, arcing is reduced by very stable plasma operation, and sputtering by ions can be reduced by operating with a cold plasma in front of the vessel walls. However, sputtering by energetic neutrals, which impinge on all areas of the vessel walls, is likely to be the most critical process because ions lost from the plasma recycle as neutrals or have to be refuelled by neutrals leading to the charge exchange processes in the plasma. In order to quantify the wall erosion, ''materials factors'' (MF) have been introduced in the following for the different erosion processes. (orig.)

User's manual of self learning gas puffing system for plasma density control

International Nuclear Information System (INIS)

Tanahashi, S.

1989-04-01

Pre-programmed gas puffing is often used to get adequet plasma density wave forms in the pulse operating devices for fusion experiments. This method has a defect that preset values have to be adjusted manually in accordance with changes of out gassing rate in successive shots. In order to remove this defect, a self learning system has been developed so as to keep the plasma density close to a given reference waveform. After a few succesive shots, it accomplishes self learning and is ready to keep up with a gradual change of the wall condition. This manual gives the usage of the system and the program list written in BASIC and ASSEMBLER languages. (author)

ICRF heating on helical devices

International Nuclear Information System (INIS)

Rasmussen, D.A.; Lyon, J.F.; Hoffman, D.J.; Murakami, M.; England, A.C.; Wilgen, J.B.; Jaeger, E.F.; Wang, C.; Batchelor, D.B.

1995-01-01

Ion cyclotron range of frequency (ICRF) heating is currently in use on CHS and W7-AS and is a major element of the heating planned for steady state helical devices. In helical devices, the lack of a toroidal current eliminates both disruptions and the need for ICRF current drive, simplifying the design of antenna structures as compared to tokamak applications. However the survivability of plasma facing components and steady state cooling issues are directly applicable to tokamak devices. Results from LHD steady state experiments should be available on a time scale to strongly influence the next generation of steady state tokamak experiments. The helical plasma geometry provides challenges not faced with tokamak ICRF heating, including the potential for enhanced fast ion losses, impurity accumulation, limited access for antenna structures, and open magnetic field lines in the plasma edge. The present results and near term plans provide the basis for steady state ICRF heating of larger helical devices. An approach which includes direct electron, mode conversion, ion minority and ion Bernstein wave heating addresses these issues

ICRF heating on helical devices

International Nuclear Information System (INIS)

Rasmussen, D.A.; Lyon, J.F.; Hoffman, D.J.

1995-01-01

Ion cyclotron range of frequency (ICRF) heating is currently in use on CHS and W7AS and is a major element of the heating planned for steady state helical devices. In helical devices, the lack of a toroidal current eliminates both disruptions and the need for ICRF current drive, simplifying the design of antenna structures as compared to tokamak applications. However the survivability of plasma facing components and steady state cooling issues are directly applicable to tokamak devices. Results from LHD steady state experiments should be available on a time scale to strongly influence the next generation of steady state tokamak experiments. The helical plasma geometry provides challenges not faced with tokamak ICRF heating, including the potential for enhanced fast ion losses, impurity accumulation, limited access for antenna structures, and open magnetic field lines in the plasma edge. The present results and near term plans provide the basis for steady state ICRF heating of larger helical devices. An approach which includes direct electron, mode conversion, ion minority and ion Bernstein wave heating addresses these issues

Centrifugal Separation Device Based on Two-Layer Laminar Flow in Microchannels for High-Throughput and Continuous Blood Cell/Plasma Separation

Science.gov (United States)

Taizo Kobayashi,; Taisuke Funamoto,; Makoto Hosaka,; Satoshi Konishi,

2010-07-01

This paper presents a novel type of centrifugation device that is based on the two-layer laminar flow in micro flow channels for continuous blood cell/plasma separation. We propose to rotate the flow channels which are arranged along the circumference around the rotational axis. Downsizing the channel width reduced both the cell sedimentation time and the required centrifugal force, because the channel width corresponds to the centrifugal sedimentation length. First, plasma and cells were continuously extracted from pig blood in each of the branch channels using a milled acrylic prototype device (channel width = 800 μm, volume = 150 μl). Next, the relationship between the channel width (125, 250, and 500 μm) and the sedimentation time taken for various centrifugal forces (2.3, 9, 36, and 145 G) was evaluated using the downsized microchannels fabricated by hot-embossing and thermal bonding technologies. Using downsized microchannels with a width of 125 μm successfully reduced the sedimentation time to 85 s as compared to the sedimentation time of 270 s for a channel of a width of 500 μm, when a centrifugal force of 2.3 G was applied. The use of the proposed device did not result in obvious hemolysis at the centrifugal forces lower than 335 G.

The plasma-wall interaction region: a key low temperature plasma for controlled fusion

International Nuclear Information System (INIS)

Counsell, G F

2002-01-01

The plasma-wall interaction region of a fusion device provides the interface between the hot core plasma and the material surfaces. To obtain acceptably low levels of erosion from these surfaces requires most of the power leaving the core to be radiated. This is accomplished in existing devices by encouraging plasma detachment, in which the hot plasma arriving in the region is cooled by volume recombination and ion-neutral momentum transfer with a dense population of neutrals recycled from the surface. The result is a low temperature (1 eV e e >10 19 m -3 ) but weakly ionized (n 0 >10 20 m -3 , n e /n 0 <0.1) plasma found nowhere else in the fusion environment. This plasma provides many of the conditions found in industrial plasmas exploiting plasma chemistry and the presence of carbon in the region (in the form of carbon-fibre composite used in the plasma facing materials) can result in the formation of deposited hydrocarbon films. The plasma-wall interaction region is therefore among the most difficult in fusion to model, requiring an understanding of atomic, molecular and surface physics issues

Production of a large, quiescent, magnetized plasma

Science.gov (United States)

Landt, D. L.; Ajmera, R. C.

1976-01-01

An experimental device is described which produces a large homogeneous quiescent magnetized plasma. In this device, the plasma is created in an evacuated brass cylinder by ionizing collisions between electrons emitted from a large-diameter electron gun and argon atoms in the chamber. Typical experimentally measured values of the electron temperature and density are presented which were obtained with a glass-insulated planar Langmuir probe. It is noted that the present device facilitates the study of phenomena such as waves and diffusion in magnetized plasmas.

Soft x-ray measurements in the FN-II dense plasma focus device for different anode configurations

International Nuclear Information System (INIS)

Rojo-Blanco, C; Castillo-Mejía, F; Rangel-Gutiérrez, J; Herrera-Velázquez, J J E

2012-01-01

A study of the soft x-ray emission is presented, for a low energy (4.8 kJ) dense plasma focus device. Three Quantrad Si PIN-diodes with differential filter combinations of Be, Al, Ti, Ni, and Mo are employed as time-resolved x-ray detectors. The x-ray flux in different energy windows is measured as function of the deuterium filling pressure. A comparison is made for three anode configurations: (a) hollow, (b) flat, and (c) 2mm diameter W needle.

Plasma electron losses in a multidipole plasma

International Nuclear Information System (INIS)

Haworth, M.D.

1983-01-01

The magnitude of the plasma electron cusp losses in a multidipole plasma device is determined by using a plasma electron heating technique. This method consists of suddenly generating approximately monoenergetic test electrons inside the multidipole plasma, which is in a steady-state equilibrium prior to the introduction of the test electrons. The Coulomb collisions between the test electrons and the plasma electrons result in heating the plasma electrons. The experimentally measured time evolution of the plasma electron temperature is compared with that predicted by a kinetic-theory model which calculates the time evolution of the test electron and the plasma electron distribution functions. The analytical solution of the plasma electron heating rate when the test electrons are first introduced into the plasma predicts that there is no dependence on ion mass. Experimental results in helium, neon, argon, and krypton multidipole plasmas confirm this prediction. The time-evolved solution of the kinetic equations must be solved numerically, and these results (when coupled with the experimental heating results) show that the plasma electron cusp-loss width is on the order of an electron Larmor radius

Novel atmospheric pressure plasma device releasing atomic hydrogen: reduction of microbial-contaminants and OH radicals in the air

International Nuclear Information System (INIS)

Nojima, Hideo; Park, Rae-Eun; Kwon, Jun-Hyoun; Suh, Inseon; Jeon, Junsang; Ha, Eunju; On, Hyeon-Ki; Kim, Hye-Ryung; Choi, KyoungHui; Lee, Kwang-Hee; Seong, Baik-Lin; Jung, Hoon; Kang, Shin Jung; Namba, Shinichi; Takiyama, Ken

2007-01-01

A novel atmospheric pressure plasma device releasing atomic hydrogen has been developed. This device has specific properties such as (1) deactivation of airborne microbial-contaminants, (2) neutralization of indoor OH radicals and (3) being harmless to the human body. It consists of a ceramic plate as a positive ion generation electrode and a needle-shaped electrode as an electron emission electrode. Release of atomic hydrogen from the device has been investigated by the spectroscopic method. Optical emission of atomic hydrogen probably due to recombination of positive ions, H + (H 2 O)n, generated from the ceramic plate electrode and electrons emitted from the needle-shaped electrode have been clearly observed in the He gas (including water vapour) environment. The efficacy of the device to reduce airborne concentrations of influenza virus, bacteria, mould fungi and allergens has been evaluated. 99.6% of airborne influenza virus has been deactivated with the operation of the device compared with the control test in a 1 m 3 chamber after 60 min. The neutralization of the OH radical has been investigated by spectroscopic and biological methods. A remarkable reduction of the OH radical in the air by operation of the device has been observed by laser-induced fluorescence spectroscopy. The cell protection effects of the device against OH radicals in the air have been observed. Furthermore, the side effects have been checked by animal experiments. The harmlessness of the device has been confirmed

Surface modification and characterization of indium-tin oxide for organic light-emitting devices.

Science.gov (United States)

Zhong, Z Y; Jiang, Y D

2006-10-15

In this work, we used different treatment methods (ultrasonic degreasing, hydrochloric acid treatment, and oxygen plasma) to modify the surfaces of indium-tin oxide (ITO) substrates for organic light-emitting devices. The surface properties of treated ITO substrates were studied by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), sheet resistance, contact angle, and surface energy measurements. Experimental results show that the ITO surface properties are closely related to the treatment methods, and the oxygen plasma is more efficient than the other treatments since it brings about smoother surfaces, lower sheet resistance, higher work function, and higher surface energy and polarity of the ITO substrate. Moreover, polymer light-emitting electrochemical cells (PLECs) with differently treated ITO substrates as device electrodes were fabricated and characterized. It is found that surface treatments of ITO substrates have a certain degree of influence upon the injection current, brightness, and efficiency, but hardly upon the turn-on voltages of current injection and light emission, which are in agreement with the measured optical energy gap of the electroluminescent polymer. The oxygen plasma treatment on the ITO substrate yields the best performance of PLECs, due to the improvement of interface formation and electrical contact of the ITO substrate with the polymer blend in the PLECs.

Controlled fusion and plasma physics

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-31

This document presents the several speeches that took place during the 22nd European Physical Society conference on Controlled Fusion and Plasma Physics in Bournemouth, UK, between the 2nd and 7th July 1995. The talks deal with new experiments carried out on several tokamaks, particularly Tore Supra, concerning plasma confinement and fusion. Some information on specific fusion devices or tokamak devices is provided, as well as results of experiments concerning plasma instability. Separate abstracts were prepared for all the 31 papers in this volume. (TEC).

Controlled fusion and plasma physics

International Nuclear Information System (INIS)

1995-01-01

This document presents the several speeches that took place during the 22nd European Physical Society conference on Controlled Fusion and Plasma Physics in Bournemouth, UK, between the 2nd and 7th July 1995. The talks deal with new experiments carried out on several tokamaks, particularly Tore Supra, concerning plasma confinement and fusion. Some information on specific fusion devices or tokamak devices is provided, as well as results of experiments concerning plasma instability. Separate abstracts were prepared for all the 31 papers in this volume. (TEC)

Controlled fusion and plasma physics

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-12-31

This document presents the several speeches that took place during the 22nd European Physical Society conference on Controlled Fusion and Plasma Physics in Bournemouth, UK, between the 2nd and 7th July 1995. The talks deal with new experiments carried out on several tokamaks, particularly Tore Supra, concerning plasma confinement and fusion. Some information on specific fusion devices or tokamak devices is provided, as well as results of experiments concerning plasma instability. Separate abstracts were prepared for all the 31 papers in this volume. (TEC).

Plasma Doping - Enabling Technology for High Dose Logic and Memory Applications

International Nuclear Information System (INIS)

Miller, T.; Godet, L.; Papasouliotis, G. D.; Singh, V.

2008-01-01

As logic and memory device dimensions shrink with each generation, there are more high dose implants at lower energies. Examples include dual poly gate (also referred to as counter-doped poly), elevated source drain and contact plug implants. Plasma Doping technology throughput and dopant profile benefits at these ultra high dose and lower energy conditions have been well established [1,2,3]. For the first time a production-worthy plasma doping implanter, the VIISta PLAD tool, has been developed with unique architecture suited for precise and repeatable dopant placement. Critical elements of the architecture include pulsed DC wafer bias, closed-loop dosimetry and a uniform low energy, high density plasma source. In this paper key performance metrics such as dose uniformity, dose repeatability and dopant profile control will be presented that demonstrate the production-worthiness of the VIISta PLAD tool for several high dose applications.

Calculation of transport coefficients in an axisymmetric plasma

International Nuclear Information System (INIS)

Shumaker, D.E.

1976-01-01

A method of calculating the transport coefficient in an axisymmetric toroidal plasma is presented. This method is useful in calculating the transport coefficients in a Tokamak plasma confinement device. The particle density and temperature are shown to be a constant on a magnetic flux surface. Transport equations are given for the total particle flux and total energy flux crossing a closed toroidal surface. Also transport equations are given for the toroidal magnetic flux. A computer code was written to calculate the transport coefficients for a three species plasma, electrons and two species of ions. This is useful for calculating the transport coefficients of a plasma which contains impurities. It was found that the particle and energy transport coefficients are increased by a large amount, and the transport coefficients for the toroidal magnetic field are reduced by a small amount. For example, a deuterium plasma with 1.3 percent oxygen, one of the particle transport coefficients is increased by a factor of about four. The transport coefficients for the toroidal magnetic flux are reduced by about 20 percent. The increase in the particle transport coefficient is due to the collisional scattering of the deuterons by the heavy oxygen ions which is larger than the deuteron electron scattering, the normal process for particle transport in a two species plasma. The reduction in the toroidal magnetic flux transport coefficients are left unexplained

Plasma heating

International Nuclear Information System (INIS)

Wilhelm, R.

1989-01-01

Successful plasma heating is essential in present fusion experiments, for the demonstration of DpT burn in future devices and finally for the fusion reactor itself. This paper discusses the common heating systems with respect to their present performance and their applicability to future fusion devices. The comparative discussion is oriented to the various function of heating, which are: - plasma heating to fusion-relevant parameters and to ignition in future machines, -non-inductive, steady-pstate current drive, - plasma profile control, -neutral gas breakdown and plasma build-up. In view of these different functions, the potential of neutral beam injection (NBI) and the various schemes of wave heating (ECRH, LH, ICRH and Alven wave heating) is analyzed in more detail. The analysis includes assessments of the present physical and technical state of these heating methods, and makes suggestions for future developments and about outstanding problems. Specific attention is given to the still critical problem of efficient current drive, especially with respect to further extrapolation towards an economically operating tokamak reactor. Remarks on issues such as reliability, maintenance and economy conclude this comparative overview on plasma heating systems. (author). 43 refs.; 13 figs.; 3 tabs

Rapid Atmospheric-Pressure-Plasma-Jet Processed Porous Materials for Energy Harvesting and Storage Devices

Directory of Open Access Journals (Sweden)

Jian-Zhang Chen

2015-01-01

Full Text Available Atmospheric pressure plasma jet (APPJ technology is a versatile technology that has been applied in many energy harvesting and storage devices. This feature article provides an overview of the advances in APPJ technology and its application to solar cells and batteries. The ultrafast APPJ sintering of nanoporous oxides and 3D reduced graphene oxide nanosheets with accompanying optical emission spectroscopy analyses are described in detail. The applications of these nanoporous materials to photoanodes and counter electrodes of dye-sensitized solar cells are described. An ultrashort treatment (1 min on graphite felt electrodes of flow batteries also significantly improves the energy efficiency.

Dynacore Final Report , Plasma Physics prototype

OpenAIRE

Lourens, W.

2000-01-01

The generation and behaviour of plasma in a fusion device and its interaction with sur-rounding materials is studied by observing several phenomena that will accompany a plasma discharge. These phenomena are recorded by means of so called Diagnostics. These are instruments that comprise complex electronic equipment, coupled to various sensors. The generation of the plasma is also governed by electronic systems that control different parameters of the fusion device, the Tokamak, and of auxilia...

Device of supporting a vacuum plasma vessel

International Nuclear Information System (INIS)

Kanoi, Minoru; Hori, Yasuro.

1980-01-01

Purpose: To improve the earthquake-resistance of a vacuum plasma vessel by equalizing the natural vibrations of a vibrating system formed by supporting mechanisms of the respective sectors of the vessel. Constitution: The vacuum plasma vessel is constructed of bellows interposed among a plurality of thick sector-like rings and the rings, which are respectively supported by supporting mechanisms. Thus, the vibrating systems are divided into the rings interposed with the bellows, arms as the supporting mechanisms, and posts. The natural vibrations of these vibrating systems are equalized to each other by suitably adjusting the configurations and the sized of the arms and the posts or the weight or the like of the rings. Therefore, the respective rings become vibrated at the natural vibrations equal to each other so as to largely reduce the stresses produced at both ends of the bellows. Accordingly, it can remarkably improve the earthquake-resistance of the entire plasma vessel. (Sekiya, K.)

Enhanced performance of CdS/CdTe thin-film devices through temperature profiling techniques applied to close-spaced sublimation deposition

Energy Technology Data Exchange (ETDEWEB)

Xiaonan Li; Sheldon, P.; Moutinho, H.; Matson, R. [National Renewable Energy Lab., Golden, CO (United States)

1996-05-01

The authors describe a methodology developed and applied to the close-spaced sublimation technique for thin-film CdTe deposition. The developed temperature profiles consisted of three discrete temperature segments, which the authors called the nucleation, plugging, and annealing temperatures. They have demonstrated that these temperature profiles can be used to grow large-grain material, plug pinholes, and improve CdS/CdTe photovoltaic device performance by about 15%. The improved material and device properties have been obtained while maintaining deposition temperatures compatible with commercially available substrates. This temperature profiling technique can be easily applied to a manufacturing environment by adjusting the temperature as a function of substrate position instead of time.

MHD Effects of a Ferritic Wall on Tokamak Plasmas

Science.gov (United States)

Hughes, Paul E.

It has been recognized for some time that the very high fluence of fast (14.1MeV) neutrons produced by deuterium-tritium fusion will represent a major materials challenge for the development of next-generation fusion energy projects such as a fusion component test facility and demonstration fusion power reactor. The best-understood and most promising solutions presently available are a family of low-activation steels originally developed for use in fission reactors, but the ferromagnetic properties of these steels represent a danger to plasma confinement through enhancement of magnetohydrodynamic instabilities and increased susceptibility to error fields. At present, experimental research into the effects of ferromagnetic materials on MHD stability in toroidal geometry has been confined to demonstrating that it is still possible to operate an advanced tokamak in the presence of ferromagnetic components. In order to better quantify the effects of ferromagnetic materials on tokamak plasma stability, a new ferritic wall has been installated in the High Beta Tokamak---Extended Pulse (HBT-EP) device. The development, assembly, installation, and testing of this wall as a modular upgrade is described, and the effect of the wall on machine performance is characterized. Comparative studies of plasma dynamics with the ferritic wall close-fitting against similar plasmas with the ferritic wall retracted demonstrate substantial effects on plasma stability. Resonant magnetic perturbations (RMPs) are applied, demonstrating a 50% increase in n = 1 plasma response amplitude when the ferritic wall is near the plasma. Susceptibility of plasmas to disruption events increases by a factor of 2 or more with the ferritic wall inserted, as disruptions are observed earlier with greater frequency. Growth rates of external kink instabilities are observed to be twice as large in the presence of a close-fitting ferritic wall. Initial studies are made of the influence of mode rotation frequency

Closing the Gap: Human Factors in Cross-Device Media Synchronization

NARCIS (Netherlands)

Mu, M.; Fawcett, L.; Bird, J.; Jellicoe, J.; Simpson, S.; Stokking, H.; Race, N.

2017-01-01

The continuing growth in the mobile phone arena, particularly in terms of device capabilities and ownership, is having a transformational impact on media consumption. It is now possible to consider orchestrated multistream experiences delivered across many devices, rather than the playback of

Development of a magnetized coaxial plasma gun for compact toroid injection into the C-2 field-reversed configuration device.

Science.gov (United States)

Matsumoto, T; Sekiguchi, J; Asai, T; Gota, H; Garate, E; Allfrey, I; Valentine, T; Morehouse, M; Roche, T; Kinley, J; Aefsky, S; Cordero, M; Waggoner, W; Binderbauer, M; Tajima, T

2016-05-01

A compact toroid (CT) injector was developed for the C-2 device, primarily for refueling of field-reversed configurations. The CTs are formed by a magnetized coaxial plasma gun (MCPG), which consists of coaxial cylindrical electrodes and a bias coil for creating a magnetic field. First, a plasma ring is generated by a discharge between the electrodes and is accelerated by Lorenz self-force. Then, the plasma ring is captured by an interlinkage flux (poloidal flux). Finally, the fully formed CT is ejected from the MCPG. The MCPG described herein has two gas injection ports that are arranged tangentially on the outer electrode. A tungsten-coated inner electrode has a head which can be replaced with a longer one to extend the length of the acceleration region for the CT. The developed MCPG has achieved supersonic CT velocities of ∼100 km/s. Plasma parameters for electron density, electron temperature, and the number of particles are ∼5 × 10(21) m(-3), ∼40 eV, and 0.5-1.0 × 10(19), respectively.

Development of a magnetized coaxial plasma gun for compact toroid injection into the C-2 field-reversed configuration device

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, T., E-mail: cstd14003@g.nihon-u.ac.jp; Sekiguchi, J.; Asai, T. [College of Science and Technology, Nihon University, 1-8-14 Kanda, Chiyoda-ku, Tokyo 1018308 (Japan); Gota, H.; Garate, E.; Allfrey, I.; Valentine, T.; Morehouse, M.; Roche, T.; Kinley, J.; Aefsky, S.; Cordero, M.; Waggoner, W.; Binderbauer, M. [Tri Alpha Energy, Inc., P.O. Box 7010 Rancho Santa Margarita, California 92688 (United States); Tajima, T. [Tri Alpha Energy, Inc., P.O. Box 7010 Rancho Santa Margarita, California 92688 (United States); Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)

2016-05-15

A compact toroid (CT) injector was developed for the C-2 device, primarily for refueling of field-reversed configurations. The CTs are formed by a magnetized coaxial plasma gun (MCPG), which consists of coaxial cylindrical electrodes and a bias coil for creating a magnetic field. First, a plasma ring is generated by a discharge between the electrodes and is accelerated by Lorenz self-force. Then, the plasma ring is captured by an interlinkage flux (poloidal flux). Finally, the fully formed CT is ejected from the MCPG. The MCPG described herein has two gas injection ports that are arranged tangentially on the outer electrode. A tungsten-coated inner electrode has a head which can be replaced with a longer one to extend the length of the acceleration region for the CT. The developed MCPG has achieved supersonic CT velocities of ∼100 km/s. Plasma parameters for electron density, electron temperature, and the number of particles are ∼5 × 10{sup 21} m{sup −3}, ∼40 eV, and 0.5–1.0 × 10{sup 19}, respectively.

Development of a magnetized coaxial plasma gun for compact toroid injection into the C-2 field-reversed configuration device

International Nuclear Information System (INIS)

Matsumoto, T.; Sekiguchi, J.; Asai, T.; Gota, H.; Garate, E.; Allfrey, I.; Valentine, T.; Morehouse, M.; Roche, T.; Kinley, J.; Aefsky, S.; Cordero, M.; Waggoner, W.; Binderbauer, M.; Tajima, T.

2016-01-01

A compact toroid (CT) injector was developed for the C-2 device, primarily for refueling of field-reversed configurations. The CTs are formed by a magnetized coaxial plasma gun (MCPG), which consists of coaxial cylindrical electrodes and a bias coil for creating a magnetic field. First, a plasma ring is generated by a discharge between the electrodes and is accelerated by Lorenz self-force. Then, the plasma ring is captured by an interlinkage flux (poloidal flux). Finally, the fully formed CT is ejected from the MCPG. The MCPG described herein has two gas injection ports that are arranged tangentially on the outer electrode. A tungsten-coated inner electrode has a head which can be replaced with a longer one to extend the length of the acceleration region for the CT. The developed MCPG has achieved supersonic CT velocities of ∼100 km/s. Plasma parameters for electron density, electron temperature, and the number of particles are ∼5 × 10"2"1 m"−"3, ∼40 eV, and 0.5–1.0 × 10"1"9, respectively.

Bursty fluctuation characteristics in SOL/divertor plasmas of Large Helical Device

International Nuclear Information System (INIS)

Ohno, N.; Masuzaki, S.; Morisaki, T.; Ohyabu, N.; Komori, A.; Budaev, V.P.; Miyoshi, H.; Takamura, S.

2006-10-01

Bursty electrostatic fluctuation in the scrape off layer (SOL) and the divertor region of the Large Helical Device (LHD) have been investigated by using a Langmuir probe array on a divertor plate and a reciprocating Langmuir probe. Large positive bursty events were often observed in the ion saturation current measured with a divertor probe near the divertor leg at which the magnetic line of force connected to the area of a low-field side with a short connection length. Condition averaging result of the positive bursty events indicates the intermittent feature with a rapid increase and a slow decay is similar to that of plasma blobs observed in tokamaks. On the other hand, at a striking point with a long connection length, negative spikes were observed. Statistical analysis based on probability distribution function (PDF) was employed to investigate the bursty fluctuation property. The observed scaling exponents disagree with the predictions for the self-organized criticality (SOC) paradigm. (author)

Rational surfaces, ExB sheared flows and transport interplay in fusion plasmas

International Nuclear Information System (INIS)

Hidalgo, C.; Pedrosa, M.A.; Erents, K.

2002-01-01