Selective Plasma Etching of Polymeric Substrates for Advanced Applications

PubMed Central

Puliyalil, Harinarayanan; Cvelbar, Uroš

2016-01-01

In today’s nanoworld, there is a strong need to manipulate and process materials on an atom-by-atom scale with new tools such as reactive plasma, which in some states enables high selectivity of interaction between plasma species and materials. These interactions first involve preferential interactions with precise bonds in materials and later cause etching. This typically occurs based on material stability, which leads to preferential etching of one material over other. This process is especially interesting for polymeric substrates with increasing complexity and a “zoo” of bonds, which are used in numerous applications. In this comprehensive summary, we encompass the complete selective etching of polymers and polymer matrix micro-/nanocomposites with plasma and unravel the mechanisms behind the scenes, which ultimately leads to the enhancement of surface properties and device performance. PMID:28335238

An overview of research activities on materials for nuclear applications at the INL Safety, Tritium and Applied Research facility

NASA Astrophysics Data System (ADS)

Calderoni, P.; Sharpe, J.; Shimada, M.; Denny, B.; Pawelko, B.; Schuetz, S.; Longhurst, G.; Hatano, Y.; Hara, M.; Oya, Y.; Otsuka, T.; Katayama, K.; Konishi, S.; Noborio, K.; Yamamoto, Y.

2011-10-01

The Safety, Tritium and Applied Research facility at the Idaho National Laboratory is a US Department of Energy National User Facility engaged in various aspects of materials research for nuclear applications related to fusion and advanced fission systems. Research activities are mainly focused on the interaction of tritium with materials, in particular plasma facing components, liquid breeders, high temperature coolants, fuel cladding, cooling and blanket structures and heat exchangers. Other activities include validation and verification experiments in support of the Fusion Safety Program, such as beryllium dust reactivity and dust transport in vacuum vessels, and support of Advanced Test Reactor irradiation experiments. This paper presents an overview of the programs engaged in the activities, which include the US-Japan TITAN collaboration, the US ITER program, the Next Generation Power Plant program and the tritium production program, and a presentation of ongoing experiments as well as a summary of recent results with emphasis on fusion relevant materials.

An Electrothermal Plasma Source Developed for Simulation of Transient Heat Loads in Future Large Fusion Devices

NASA Astrophysics Data System (ADS)

Gebhart, Trey; Baylor, Larry; Winfrey, Leigh

2016-10-01

The realization of fusion energy requires materials that can withstand high heat and particle fluxes at the plasma material interface. In this work, an electrothermal (ET) plasma source has been designed as a possible transient heat flux source for a linear plasma material interaction device. An ET plasma source operates in the ablative arc regime, which is driven by a DC capacitive discharge. The current travels through the 4mm bore of a boron nitride liner and subsequently ablates and ionizes the liner material. This results in a high density plasma with a large unidirectional bulk flow out of the source exit. The pulse length for the ET source has been optimized using a pulse forming network to have a duration of 1ms at full-width half maximum. The peak currents and maximum source energies seen in this system are 2kA and 5kJ. The goal of this work is to show that the ET source produces electron densities and heat fluxes that are comparable to transient events in future large magnetic confinement fusion devices. Heat flux, plasma temperature, and plasma density were determined for each test shot using infrared imaging and optical spectroscopy techniques. This work will compare the ET source output (heat flux, temperature, and density) with and without an applied magnetic field. Research sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U. S. Department of Energy.

Addressing Research and Development Gaps for Plasma-Material Interactions with Linear Plasma Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rapp, Juergen

Plasma-material interactions in future fusion reactors have been identified as a knowledge gap to be dealt with before any next step device past ITER can be built. The challenges are manifold. They are related to power dissipation so that the heat fluxes to the plasma-facing components can be kept at technologically feasible levels; maximization of the lifetime of divertor plasma-facing components that allow for steadystate operation in a reactor to reach the neutron fluence required; the tritium inventory (storage) in the plasma-facing components, which can lead to potential safety concerns and reduction in the fuel efficiency; and it is relatedmore » to the technology of the plasma-facing components itself, which should demonstrate structural integrity under the high temperatures and high neutron fluence. While the dissipation of power exhaust can and should be addressed in high power toroidal devices, the interaction of the plasma with the materials can be best addressed in dedicated linear devices due to their cost effectiveness and ability to address urgent research and development gaps more timely. However, new linear plasma devices are needed to investigate the PMI under fusion reactor conditions and test novel plasma-facing components. Existing linear devices are limited either in their flux, their reactor-relevant plasma transport regimes in front of the target, their fluence, or their ability to test material samples a priori exposed to high neutron fluence. The proposed Material Plasma Exposure eXperiment (MPEX) is meant to address those deficiencies and will be designed to fulfill the fusion reactor-relevant plasma parameters as well as the ability to expose a priori neutron activated materials to plasmas.« less

FUSION ENERGY SCIENCES WORKSHOP ON PLASMA MATERIALS INTERACTIONS: Report on Science Challenges and Research Opportunities in Plasma Materials Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maingi, Rajesh; Zinkle, Steven J.; Foster, Mark S.

2015-05-01

The realization of controlled thermonuclear fusion as an energy source would transform society, providing a nearly limitless energy source with renewable fuel. Under the auspices of the U.S. Department of Energy, the Fusion Energy Sciences (FES) program management recently launched a series of technical workshops to “seek community engagement and input for future program planning activities” in the targeted areas of (1) Integrated Simulation for Magnetic Fusion Energy Sciences, (2) Control of Transients, (3) Plasma Science Frontiers, and (4) Plasma-Materials Interactions aka Plasma-Materials Interface (PMI). Over the past decade, a number of strategic planning activities1-6 have highlighted PMI and plasmamore » facing components as a major knowledge gap, which should be a priority for fusion research towards ITER and future demonstration fusion energy systems. There is a strong international consensus that new PMI solutions are required in order for fusion to advance beyond ITER. The goal of the 2015 PMI community workshop was to review recent innovations and improvements in understanding the challenging PMI issues, identify high-priority scientific challenges in PMI, and to discuss potential options to address those challenges. The community response to the PMI research assessment was enthusiastic, with over 80 participants involved in the open workshop held at Princeton Plasma Physics Laboratory on May 4-7, 2015. The workshop provided a useful forum for the scientific community to review progress in scientific understanding achieved during the past decade, and to openly discuss high-priority unresolved research questions. One of the key outcomes of the workshop was a focused set of community-initiated Priority Research Directions (PRDs) for PMI. Five PRDs were identified, labeled A-E, which represent community consensus on the most urgent near-term PMI scientific issues. For each PRD, an assessment was made of the scientific challenges, as well as a set of actions to address those challenges. No prioritization was attempted amongst these five PRDs. We note that ITER, an international collaborative project to substantially extend fusion science and technology, is implicitly a driver and beneficiary of the research described in these PRDs; specific ITER issues are discussed in the background and PRD chapters. For succinctness, we describe these PRDs directly below; a brief introduction to magnetic fusion and the workshop process/timeline is given in Chapter I, and panelists are listed in the Appendix.« less

Early Career. Harnessing nanotechnology for fusion plasma-material interface research in an in-situ particle-surface interaction facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allain, Jean Paul

2014-08-08

This project consisted of fundamental and applied research of advanced in-situ particle-beam interactions with surfaces/interfaces to discover novel materials able to tolerate intense conditions at the plasma-material interface (PMI) in future fusion burning plasma devices. The project established a novel facility that is capable of not only characterizing new fusion nanomaterials but, more importantly probing and manipulating materials at the nanoscale while performing subsequent single-effect in-situ testing of their performance under simulated environments in fusion PMI.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, O.B. Jr.; Berry, L.A.; Sheffield, J.

This annual report on fusion energy discusses the progress on work in the following main topics: toroidal confinement experiments; atomic physics and plasma diagnostics development; plasma theory and computing; plasma-materials interactions; plasma technology; superconducting magnet development; fusion engineering design center; materials research and development; and neutron transport. (LSP)

Promoting Pre-college Science Education

NASA Astrophysics Data System (ADS)

Lee, R. L.

1999-11-01

The Fusion Education Program, with support from DOE, continues to promote pre-college science education for students and teachers using multiple approaches. An important part of our program is direct scientist-student interaction. Our ``Scientist in a Classroom'' program allows students to interact with scientists and engage in plasma science activities in the students' classroom. More than 1000 students from 11 schools have participated in this exciting program. Also, this year more than 800 students and teachers have visited the DIII--D facility and interacted with scientists to cover a broad range of technical and educational issues. Teacher-scientist interaction is imperative in professional development and each year more than 100 teachers attend workshops produced by the fusion education team. We also participate in unique learning opportunities. Members of the team, in collaboration with the San Diego County Office of Education, held a pioneering Internet-based Physics Olympiad for American and Siberian students. Our teamwork with educators helps shape material that is grade appropriate, relevant, and stimulates thinking in educators and students.

The Plasma Interaction Experiment (PIX) description and test program. [electrometers

NASA Technical Reports Server (NTRS)

Ignaczak, L. R.; Haley, F. A.; Domino, E. J.; Culp, D. H.; Shaker, F. J.

1978-01-01

The plasma interaction experiment (PIX) is a battery powered preprogrammed auxiliary payload on the LANDSAT-C launch. This experiment is part of a larger program to investigate space plasma interactions with spacecraft surfaces and components. The varying plasma densities encountered during available telemetry coverage periods are deemed sufficient to determine first order interactions between the space plasma environment and the biased experimental surfaces. The specific objectives of the PIX flight experiment are to measure the plasma coupling current and the negative voltage breakdown characteristics of a solar array segment and a gold plated steel disk. Measurements will be made over a range of surface voltages up to plus or minus kilovolt. The orbital environment will provide a range of plasma densities. The experimental surfaces will be voltage biased in a preprogrammed step sequence to optimize the data returned for each plasma region and for the available telemetry coverage.

GITR Simulation of Helium Exposed Tungsten Erosion and Redistribution in PISCES-A

NASA Astrophysics Data System (ADS)

Younkin, T. R.; Green, D. L.; Doerner, R. P.; Nishijima, D.; Drobny, J.; Canik, J. M.; Wirth, B. D.

2017-10-01

The extreme heat, charged particle, and neutron flux / fluence to plasma facing materials in magnetically confined fusion devices has motivated research to understand, predict, and mitigate the associated detrimental effects. Of relevance to the ITER divertor is the helium interaction with the tungsten divertor, the resulting erosion and migration of impurities. The linear plasma device PISCES A has performed dedicated experiments for high (4x10-22 m-2s-1) and low (4x10-21 m-2s-1) flux, 250 eV He exposed tungsten targets to assess the net and gross erosion of tungsten and volumetric transport. The temperature of the target was held between 400 and 600 degrees C. We present results of the erosion / migration / re-deposition of W during the experiment from the GITR (Global Impurity Transport) code coupled to materials response models. In particular, the modeled and experimental W I emission spectroscopy data for the 429.4 nm wavelength and net erosion through target and collector mass difference measurements are compared. Overall, the predictions are in good agreement with experiments. This material is supported by the US DOE, Office of Science, Office of Fusion Energy Sciences and Office of Advanced Scientific Computing Research through the SciDAC program on Plasma-Surface Interactions.

Plasma-wall interaction data needs critical to a Burning Core Experiment (BCX)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1985-11-01

The Division of Development and Technology has sponsored a four day US-Japan workshop ''Plasma-Wall Interaction Data Needs Critical to a Burning Core Experiment (BCX)'', held at Sandia National Laboratories, Livermore, California on June 24 to 27, 1985. The workshop, which brought together fifty scientists and engineers from the United States, Japan, Germany, and Canada, considered the plasma-material interaction and high heat flux (PMI/HHF) issues for the next generation of magnetic fusion energy devices, the Burning Core Experiment (BCX). Materials options were ranked, and a strategy for future PMI/HHF research was formulated. The foundation for international collaboration and coordination of thismore » research was also established. This volume contains the last three of the five technical sessions. The first of the three is on plasma materials interaction issues, the second is on research facilities and the third is from smaller working group meetings on graphite, beryllium, advanced materials and future collaborations.« less

Progress in Spacecraft Environment Interactions: International Space Station (ISS) Development and Operations

NASA Technical Reports Server (NTRS)

Koontz, Steve; Suggs, Robb; Schneider, Todd; Minow, Joe; Alred, John; Cooke, Bill; Mikatarian, Ron; Kramer, Leonard; Boeder, paul; Soares, Carlos

2007-01-01

The set of spacecraft interactions with the space flight environment that have produced the largest impacts on the design, verification, and operation of the International Space Station (ISS) Program during the May 2000 to May 2007 time frame are the focus of this paper. In-flight data, flight crew observations, and the results of ground-based test and analysis directly supporting programmatic and operational decision-making are reported as are the analysis and simulation efforts that have led to new knowledge and capabilities supporting current and future space explorations programs. The specific spacecraft-environment interactions that have had the greatest impact on ISS Program activities during the first several years of flight are: 1) spacecraft charging, 2) micrometeoroids and orbital debris effects, 3) ionizing radiation (both total dose to materials and single event effects [SEE] on avionics), 4) hypergolic rocket engine plume impingement effects, 5) venting/dumping of liquids, 6) spacecraft contamination effects, 7) neutral atmosphere and atomic oxygen effects, 8) satellite drag effects, and 9) solar ultraviolet effects. Orbital inclination (51.6deg) and altitude (nominally between 350 km and 460 km) determine the set of natural environment factors affecting the performance and reliability of materials and systems on ISS. ISS operates in the F2 region of Earth s ionosphere in well-defined fluxes of atomic oxygen, other ionospheric plasma species, solar UV, VUV, and x-ray radiation as well as galactic cosmic rays, trapped radiation, and solar cosmic rays. The micrometeoroid and orbital debris environment is an important determinant of spacecraft design and operations in any orbital inclination. The induced environment results from ISS interactions with the natural environment as well as environmental factors produced by ISS itself and visiting vehicles. Examples include ram-wake effects, hypergolic thruster plume impingement, materials out-gassing, venting and dumping of fluids, and specific photovoltaic (PV) power system interactions with the ionospheric plasma. Vehicle size (L) and velocity (v), combined with the magnitude and direction of the geomagnetic field (B) produce operationally significant magnetic induction voltages (VxB.L) in ISS conducting structure during high latitude flight (>+/- 45deg) during each orbit. In addition, ISS is a large vehicle and produces a deep wake structure from which both ionospheric plasma and neutrals species are largely excluded. ISS must fly in a very limited number of approved flight attitudes, so that exposure of a particular material or system to environmental factors depends upon: 1) location on ISS, 2) ISS flight configuration, 3) ISS flight attitude, and 4) variation of solar exposure (Beta angle), and hence thermal environment, with time. Finally, an induced ionizing radiation environment is produced by trapped radiation and solar/cosmic ray interactions with the relatively massive ISS structural shielding.

Monte Carlo simulation of ion-material interactions in nuclear fusion devices

NASA Astrophysics Data System (ADS)

Nieto Perez, M.; Avalos-Zuñiga, R.; Ramos, G.

2017-06-01

One of the key aspects regarding the technological development of nuclear fusion reactors is the understanding of the interaction between high-energy ions coming from the confined plasma and the materials that the plasma-facing components are made of. Among the multiple issues important to plasma-wall interactions in fusion devices, physical erosion and composition changes induced by energetic particle bombardment are considered critical due to possible material flaking, changes to surface roughness, impurity transport and the alteration of physicochemical properties of the near surface region due to phenomena such as redeposition or implantation. A Monte Carlo code named MATILDA (Modeling of Atomic Transport in Layered Dynamic Arrays) has been developed over the years to study phenomena related to ion beam bombardment such as erosion rate, composition changes, interphase mixing and material redeposition, which are relevant issues to plasma-aided manufacturing of microelectronics, components on object exposed to intense solar wind, fusion reactor technology and other important industrial fields. In the present work, the code is applied to study three cases of plasma material interactions relevant to fusion devices in order to highlight the code's capabilities: (1) the Be redeposition process on the ITER divertor, (2) physical erosion enhancement in castellated surfaces and (3) damage to multilayer mirrors used on EUV diagnostics in fusion devices due to particle bombardment.

FOREWORD: 23rd National Symposium on Plasma Science & Technology (PLASMA-2008)

NASA Astrophysics Data System (ADS)

Das, A. K.

2010-01-01

The Twentieth Century has been a defining period for Plasma Science and Technology. The state of ionized matter, so named by Irving Langmuir in the early part of twentieth century, has now evolved in to a multidisciplinary area with scientists and engineers from various specializations working together to exploit the unique properties of the plasma medium. There have been great improvements in the basic understanding of plasmas as a many body system bound by complex collective Coulomb interactions of charges, atoms, molecules, free radicals and photons. Simultaneously, many advanced plasma based technologies are increasingly being implemented for industrial and societal use. The emergence of the multination collaborative project International Thermonuclear Experimental Reactor (ITER) project has provided the much needed boost to the researchers working on thermonuclear fusion plasmas. In addition, the other plasma applications like MHD converters, hydrogen generation, advanced materials (synthesis, processing and surface modification), environment (waste beneficiation, air and water pollution management), nanotechnology (synthesis, deposition and etching), light production, heating etc are actively being pursued in governmental and industrial sectors. For India, plasma science and technology has traditionally remained an important area of research. It was nearly a century earlier that the Saha ionization relation pioneered the way to interpret experimental data from a vast range of near equilibrium plasmas. Today, Indian research contributions and technology demonstration capabilities encompass thermonuclear fusion devices, nonlinear plasma phenomena, plasma accelerators, beam plasma interactions, dusty and nonneutral plasmas, industrial plasmas and plasma processing of materials, nano synthesis and structuring, astrophysical and space plasmas etc. India's participation in the ITER programme is now reflected in increased interest in the research and development efforts on Tokamak technology and physics of magnetized fusion plasmas. Our industries have already adopted a large number of plasma processes related to manufacturing, lighting and surface engineering. Indian universities and National Institutes have successfully taken up research projects and building of demonstration equipment that are being used in strategic as well as other industrial applications. In addition, and more importantly, plasma science has triggered research and development effort in many related areas like power supplies, specialized instrumentation and controls, magnets, diagnostics and monitoring, lasers, electron beams, vacuum systems, thermal engineering, material science, fluid dynamics, molecular and nano engineering, molecular chemistry etc. In short, plasma science and technology in India has reached a stage of maturity that can be harnessed for industrial and societal use. The expertise and core competence developed over the years need to be sustained through interactions among researchers as well as nurturing of new research efforts. The Annual Plasma Symposiums have eminently worked towards achievement of that purpose. Like all years, Plasma - 2008 is built around the entire national effort in this field with a special focus on 'Plasmas in Nuclear Fuel Cycle (PANFC)'. The program includes several plenary lectures, invited talks and contributed papers. The manuscripts have been peer reviewed and compiled in the form of Conference Proceedings. I am sure that the online proceedings will be useful and serve as a valuable reference material for active researchers in this field. I would like to take this opportunity to gratefully acknowledge the help and guidance of the National Advisory Committee Chaired by Professor P K Kaw, Director, Institute of Plasma Research, Gandhinagar during the organization of this symposium. My sincere thanks to Dr S Banerjee, Director, Bhabha Atomic Research Center, an acknowledged expert in the field of Materials Science and Technology, for delivering the key note address to set the tenor of the symposium. I would also like to thank the Plasma Science Society of India (PSSI) for agreeing to hold this important event at BARC. Thanks are due to Dr L M Gantayet, Director, BTDG, BARC and chairman, Scientific Program Committee and all my colleagues in the Symposium Organizing Committee who have made this symposium possible. Finally, our thanks to all the Funding agencies, Board of Research in Nuclear Science, Department of Science and Technology, The Board of Fusion Research, and all industrial exhibitor and sponsors for their unstinted support and encouragement. Dr A K Das Chairman, Organizing Committee Bhabha Atomic Research Center, Mumbai

Understanding the Effect of Gas Dynamics in Plasma Gun Performance for Simulating Fusion Wall Response to Disruption Events

NASA Astrophysics Data System (ADS)

Riedel, Will; Underwood, Thomas; Righetti, Fabio; Cappelli, Mark

2017-10-01

In this work, the suitability of a pulsed coaxial plasma accelerator to simulate the interaction of edge-localized modes with plasma first wall materials is investigated. Experimental measurements derived from a suite of diagnostics are presented that focus on both the properties of the plasma flow and the manner in which such jets couple with material interfaces. Specific emphasis is placed on quantifying the variation in these properties using tungsten tokens exposed to the plasma plume as the gun volume is progressively filled with more neutral gas. These results are mapped to the operational dynamics of the gun via a time-resolved Schlieren cinematic visualization of the density gradient within the flow. Resulting videos indicate the existence of two distinct modes with vastly different characteristic timescales, spatial evolution, and plasma properties. Time resolved quantification of the associated plasma heat flux for both modes, including a range spanning 150 MW m-2 - 10 GW m-2, is presented using both a fast thermocouple gauge and an IR camera. Both diagnostics in conjunction with a heat transfer model provide an accurate description of the energy transfer dynamics and operational characteristics of plasma guns. This work is supported by the U.S. Department of Energy Stewardship Science Academic Program.

Toward a comprehensive UV laser ablation modeling of multicomponent materials—A non-equilibrium investigation on titanium carbide

NASA Astrophysics Data System (ADS)

Ait Oumeziane, Amina; Parisse, Jean-Denis

2018-05-01

Titanium carbide (TiC) coatings of great quality can be produced using nanosecond pulsed laser deposition (PLD). Because the deposition rate and the transfer of the target stoichiometry depend strongly on the laser-target/laser-plasma interaction as well as the composition of the laser induced plume, investigating the ruling fundamental mechanisms behind the material ablation and the plasma evolution in the background environment under PLD conditions is essential. This work, which extends previous investigations dedicated to the study of nanosecond laser ablation of pure target materials, is a first step toward a comprehensive non-equilibrium model of multicomponent ones. A laser-material interaction model coupled to a laser-plasma interaction one is presented. A UV 20 ns KrF (248 nm) laser pulse is considered. Ablation depths, plasma ignition thresholds, and shielding rates have been calculated for a wide range of laser beam fluences. A comparison of TiC behavior with pure titanium material under the same conditions is made. Plasma characteristics such as temperature and composition have been investigated. An overall correlation between the various results is presented.

8th Spacecraft Charging Technology Conference

NASA Technical Reports Server (NTRS)

Minor, J. L. (Compiler)

2004-01-01

The 8th Spacecraft Charging Technology Conference was held in Huntsville, Alabama, October 20-24, 2003. Hosted by NASA s Space Environments and Effects (SEE) Program and co-sponsored by the Air Force Research Laboratory (AFRL) and the European Space Agency (ESA), the 2003 conference saw attendance from eleven countries with over 65 oral papers and 18 poster papers. Presentation topics highlighted the latest in spacecraft charging mitigation techniques and on-orbit investigations, including: Plasma Propulsion and Tethers; Ground Testing Techniques; Interactions of Spacecraft and Systems With the Natural and Induced Plasma Environment; Materials Characterizations; Models and Computer Simulations; Environment Specifications; Current Collection and Plasma Probes in Space Plasmas; On-Orbit Investigations. A round-table discussion of international standards regarding electrostatic discharge (ESD) testing was also held with the promise of continued discussions in the off years and an official continuation at the next conference.

Design and Construction of Field Reversed Configuration Plasma Chamber for Plasma Material Interaction Studies

NASA Astrophysics Data System (ADS)

Smith, DuWayne L.

A Field Reversed Configuration (FRC) plasma source was designed and constructed to conduct high energy plasma-materials interaction studies. The purpose of these studies is the development of advanced materials for use in plasma based electric propulsion systems and nuclear fusion containment vessels. Outlined within this thesis is the basic concept of FRC plasmoid creation, an overview of the device design and integration of various diagnostics systems for plasma conditions and characterization, discussion on the variety of material defects resulting from the plasma exposure with methods and tools designed for characterization. Using a Michelson interferometer it was determined that the FRC plasma densities are on the order of ~1021 m-3. A novel dynamic pressure probe was created to measure ion velocities averaging 300 km/s. Compensating flux loop arrays were used to measure magnetic field strength and verify the existence of the FRC plasmoid and when used in combination with density measurements it was determined that the average ion temperatures are ~130 eV. X-ray Photoelectron Spectroscopy (XPS) was employed as a means of characterizing the size and shape of the plasma jet in the sample exposure positions. SEM results from preliminary studies reveal significant morphological changes on plasma facing material surfaces, and use of XRD to elucidate fuel gas-ion implantation strain rates correlated to plasma exposure energies.

Improvement of the adsorption of quaternary ammonium on polypropylene affinity membrane through the control of its surface properties.

PubMed

Hachache, Naima; Bal, Youcef; Debarnot, Dominique; Poncin-Epaillard, Fabienne

2014-02-01

Polypropylene fiber meshes were plasma-treated in order to attach new chemical functions corresponding to acidic or basic groups without altering the roughness of such thin material. An almost complete wettability of these plasma-treated materials is obtained. Because of the plasma-grafting of acid or amino moieties, such surface treatment allows increasing the adsorption rate of quaternary ammonium molecule like Aliquat 336. This increase was explained by specific interactions of ammonium head of the Aliquat 336 and hydrophilic group of plasma-treated PP, followed by the adsorption of a further layer of Aliquat 336 through hydrophobic interactions of its hydrocarbon chain. These interactions between the carrier and the polymeric surface were characterized leading to physisorption mechanism. Such new material could be applied to the extraction process since no evidence of aging was given. Copyright © 2013 Elsevier B.V. All rights reserved.

LEOrbit: A program to calculate parameters relevant to modeling Low Earth Orbit spacecraft-plasma interaction

NASA Astrophysics Data System (ADS)

Marchand, R.; Purschke, D.; Samson, J.

2013-03-01

Understanding the physics of interaction between satellites and the space environment is essential in planning and exploiting space missions. Several computer models have been developed over the years to study this interaction. In all cases, simulations are carried out in the reference frame of the spacecraft and effects such as charging, the formation of electrostatic sheaths and wakes are calculated for given conditions of the space environment. In this paper we present a program used to compute magnetic fields and a number of space plasma and space environment parameters relevant to Low Earth Orbits (LEO) spacecraft-plasma interaction modeling. Magnetic fields are obtained from the International Geophysical Reference Field (IGRF) and plasma parameters are obtained from the International Reference Ionosphere (IRI) model. All parameters are computed in the spacecraft frame of reference as a function of its six Keplerian elements. They are presented in a format that can be used directly in most spacecraft-plasma interaction models. Catalogue identifier: AENY_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENY_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 270308 No. of bytes in distributed program, including test data, etc.: 2323222 Distribution format: tar.gz Programming language: FORTRAN 90. Computer: Non specific. Operating system: Non specific. RAM: 7.1 MB Classification: 19, 4.14. External routines: IRI, IGRF (included in the package). Nature of problem: Compute magnetic field components, direction of the sun, sun visibility factor and approximate plasma parameters in the reference frame of a Low Earth Orbit satellite. Solution method: Orbit integration, calls to IGRF and IRI libraries and transformation of coordinates from geocentric to spacecraft frame reference. Restrictions: Low Earth orbits, altitudes between 150 and 2000 km. Running time: Approximately two seconds to parameterize a full orbit with 1000 points.

Plasma-material Interactions in Current Tokamaks and their Implications for Next-step Fusion Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Federici, G.; Skinner, C.H.; Brooks, J.N.

2001-01-10

The major increase in discharge duration and plasma energy in a next-step DT [deuterium-tritium] fusion reactor will give rise to important plasma-material effects that will critically influence its operation, safety, and performance. Erosion will increase to a scale of several centimeters from being barely measurable at a micron scale in today's tokamaks. Tritium co-deposited with carbon will strongly affect the operation of machines with carbon plasma-facing components. Controlling plasma wall interactions is critical to achieving high performance in present-day tokamaks and this is likely to continue to be the case in the approach to practical fusion reactors. Recognition of themore » important consequences of these phenomena has stimulated an internationally coordinated effort in the field of plasma-surface interactions supporting the Engineering Design Activities of the International Thermonuclear Experimental Reactor (ITER) project and significant progress has been made in better under standing these issues. This paper reviews the underlying physical processes and the existing experimental database of plasma-material interactions both in tokamaks and laboratory simulation facilities for conditions of direct relevance to next-step fusion reactors. Two main topical groups of interactions are considered: (i) erosion/redeposition from plasma sputtering and disruptions, including dust and flake generation, (ii) tritium retention and removal. The use of modeling tools to interpret the experimental results and make projections for conditions expected in future devices is explained. Outstanding technical issues and specific recommendations on potential R and D [Research and Development] avenues for their resolution are presented.« less

Study of the effect of collisionality and cooling on the interactions of counter-streaming plasma flows as a function of wire material

NASA Astrophysics Data System (ADS)

Collins, Gilbert; Valenzuela, Julio; Aybar, Nicholas; Conti, Fabio; Beg, Farhat

2017-10-01

We report on the effects wire material on collisionality and radiative cooling on the interactions of counter-streaming plasma jets produced by conical wire arrays on the 200 kA GenASIS driver. In these interactions, mean free path (λmfp) scales with jet velocity (vjet4),atomic mass (A2), and ionization (Z*-4), while cooling scales with atomic mass. By changing the material of the jets one can create slowly cooling, weakly collisional regimes using C, Al, or Cu, or strongly cooled, effectively collisionless plasmas using Mo or W. The former produced smooth shocks soon after the jets collide (near the peak current of 150 ns) that grew in size over time. Interactions of the latter produced multiple structures of a different shape, at a later time ( 300 ns) that dissipated rapidly compared to the lower Z materials. We will report on the scaleability of these different materials to astrophysical phenomena. This work was partially supported by the Department of Energy Grant Number DE-SC0014493.

Shuttle-era experiments in the area of plasma flow interactions with bodies in space

NASA Technical Reports Server (NTRS)

Samir, U.; Stone, N. H.

1980-01-01

A new experimental approach is discussed that can be adopted for studies in the area of plasma flow interactions with bodies in space. The potential use of the Space Shuttle/Orbiter as a near-earth plasma laboratory for studies in space plasma physics and particularly in solar system plasmas is discussed. This new experimental approach holds great promise for studies in the supersonic and sub-Alfvenic flow regime which has applications to the motion of natural satellites around their mother planets in the solar-system (e.g., the satellite Io around the planet Jupiter). A well conceived experimental and theoretical program can lead to a better physical understanding regarding the validity and range of applicability of using gasdynamic, kinetic, and fluid approaches in describing collisionless plasma flow interactions with bodies in a variety of flow regimes. In addition to the above scientific aspects of the program, significant technological advances can be achieved regarding the interaction of space probes in planetary atmospheres/ionospheres and the reliability of using various plasma diagnostic devices on board spacecraft and large space platforms.

Heat flux estimates of power balance on Proto-MPEX with IR imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Showers, M., E-mail: mshower1@vols.utk.edu; Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831; Biewer, T. M.

The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) at Oak Ridge National Laboratory (ORNL) is a precursor linear plasma device to the Material Plasma Exposure eXperiment (MPEX), which will study plasma material interactions (PMIs) for future fusion reactors. This paper will discuss the initial steps performed towards completing a power balance on Proto-MPEX to quantify where energy is lost from the plasma, including the relevant diagnostic package implemented. Machine operating parameters that will improve Proto-MPEX’s performance may be identified, increasing its PMI research capabilities.

Astrophysically Relevant Dipole Studies at WiPAL

NASA Astrophysics Data System (ADS)

Endrizzi, Douglass; Forest, Cary; Wallace, John; WiPAL Team

2015-11-01

A novel terrella experiment is being developed to immerse a dipole magnetic field in the large, unmagnetized, and fully ionized background plasma of WiPAL (Wisconsin Plasma Astrophysics Lab). This allows for a series of related experiments motivated by astrophysical processes, including (1) inward transport of plasma into a magnetosphere with focus on development of Kelvin-Helmholtz instabilities from boundary shear flow; (2) helicity injection and simulation of solar eruptive events via electrical breakdown along dipole field lines; (3) interaction of Coronal Mass Ejection-like flows with a target magnetosphere and dependence on background plasma pressure; (4) production of a centrifugally driven wind to study how dipolar magnetic topology changes as closed field lines open. A prototype has been developed and preliminary results will be presented. An overview of the final design and construction progress will be given. This material is based upon work supported by the NSF Graduate Research Fellowship Program.

Interactive Plasma Physics Education Using Data from Fusion Experiments

NASA Astrophysics Data System (ADS)

Calderon, Brisa; Davis, Bill; Zwicker, Andrew

2010-11-01

The Internet Plasma Physics Education Experience (IPPEX) website was created in 1996 to give users access to data from plasma and fusion experiments. Interactive material on electricity, magnetism, matter, and energy was presented to generate interest and prepare users to understand data from a fusion experiment. Initially, users were allowed to analyze real-time and archival data from the Tokamak Fusion Test Reactor (TFTR) experiment. IPPEX won numerous awards for its novel approach of allowing users to participate in ongoing research. However, the latest revisions of IPPEX were in 2001 and the interactive material is no longer functional on modern browsers. Also, access to real-time data was lost when TFTR was shut down. The interactive material on IPPEX is being rewritten in ActionScript3.0, and real-time and archival data from the National Spherical Tokamak Experiment (NSTX) will be made available to users. New tools like EFIT animations, fast cameras, and plots of important plasma parameters will be included along with an existing Java-based ``virtual tokamak.'' Screenshots from the upgraded website and future directions will be presented.

Full toroidal imaging of non-axisymmetric plasma material interaction in the National Spherical Torus Experiment divertor.

PubMed

Scotti, Filippo; Roquemore, A L; Soukhanovskii, V A

2012-10-01

A pair of two dimensional fast cameras with a wide angle view (allowing a full radial and toroidal coverage of the lower divertor) was installed in the National Spherical Torus Experiment in order to monitor non-axisymmetric effects. A custom polar remapping procedure and an absolute photometric calibration enabled the easier visualization and quantitative analysis of non-axisymmetric plasma material interaction (e.g., strike point splitting due to application of 3D fields and effects of toroidally asymmetric plasma facing components).

Initial Ferritic Wall Mode studies on HBT-EP

NASA Astrophysics Data System (ADS)

Hughes, Paul; Bialek, J.; Boozer, A.; Mauel, M. E.; Levesque, J. P.; Navratil, G. A.

2013-10-01

Low-activation ferritic steels are leading material candidates for use in next-generation fusion development experiments such as a prospective US component test facility and DEMO. Understanding the interaction of plasmas with a ferromagnetic wall will provide crucial physics for these experiments. Although the ferritic wall mode (FWM) was seen in a linear machine, the FWM was not observed in JFT-2M, probably due to eddy current stabilization. Using its high-resolution magnetic diagnostics and positionable walls, HBT-EP has begun exploring the dynamics and stability of plasma interacting with high-permeability ferritic materials tiled to reduce eddy currents. We summarize a simple model for plasma-wall interaction in the presence of ferromagnetic material, describe the design of a recently-installed set of ferritic shell segments, and report initial results. Supported by U.S. DOE Grant DE-FG02-86ER53222.

Recent progress in plasma-assisted synthesis and modification of 2D materials

NASA Astrophysics Data System (ADS)

Han, Zhao Jun; Murdock, Adrian T.; Seo, Dong Han; Bendavid, Avi

2018-07-01

Plasma represents an important technique for both the synthesis and modification of two-dimensional (2D) materials, owing to the unique plasma-material interactions which can enable effective energy transfer at the nanoscale. Non-equilibrium and non-thermal plasma techniques have been widely applied on various 2D materials, including graphene, silicene, germanene, phosphorene, hexagonal boron nitride (h-BN), and transition metal dichalcogenides such as MoS2 and WS2. Here, we review the recent progress in plasma-assisted synthesis and modification (e.g. functionalisation, doping and etching) of 2D materials and discuss the potential applications of this unique branch of 2D materials. Challenges and future research opportunities in the relevant research field are also discussed. The primary aim of this Review is to provide a better understanding of the plasma-assisted processes and to promote the utilization of 2D materials for advanced electronic, optoelectronic, sensing and energy storage applications.

The Challenges of Plasma Material Interactions in Nuclear Fusion Devices and Potential Solutions

DOE PAGES

Rapp, J.

2017-07-12

Plasma Material Interactions in future fusion reactors have been identified as a knowledge gap to be dealt with before any next step device past ITER can be built. The challenges are manifold. They are related to power dissipation so that the heat fluxes to the plasma facing components can be kept at technologically feasible levels; maximization of the lifetime of divertor plasma facing components that allow for steady-state operation in a reactor to reach the neutron fluences required; the tritium inventory (storage) in the plasma facing components, which can lead to potential safety concerns and reduction in the fuel efficiency;more » and it is related to the technology of the plasma facing components itself, which should demonstrate structural integrity under the high temperatures and neutron fluence. This contribution will give an overview and summary of those challenges together with some discussion of potential solutions. New linear plasma devices are needed to investigate the PMI under fusion reactor conditions and test novel plasma facing components. The Material Plasma Exposure eXperiment MPEX will be introduced and a status of the current R&D towards MPEX will be summarized.« less

The Challenges of Plasma Material Interactions in Nuclear Fusion Devices and Potential Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rapp, J.

Plasma Material Interactions in future fusion reactors have been identified as a knowledge gap to be dealt with before any next step device past ITER can be built. The challenges are manifold. They are related to power dissipation so that the heat fluxes to the plasma facing components can be kept at technologically feasible levels; maximization of the lifetime of divertor plasma facing components that allow for steady-state operation in a reactor to reach the neutron fluences required; the tritium inventory (storage) in the plasma facing components, which can lead to potential safety concerns and reduction in the fuel efficiency;more » and it is related to the technology of the plasma facing components itself, which should demonstrate structural integrity under the high temperatures and neutron fluence. This contribution will give an overview and summary of those challenges together with some discussion of potential solutions. New linear plasma devices are needed to investigate the PMI under fusion reactor conditions and test novel plasma facing components. The Material Plasma Exposure eXperiment MPEX will be introduced and a status of the current R&D towards MPEX will be summarized.« less

Lunar Solar Origins Exploration (LunaSOX)

NASA Technical Reports Server (NTRS)

Cooper, John F.; King, Joseph H.; Papitashvili, Natasha; Lipatov, Alexander S.; Sittler, Edward C.; Hartle, Richard E.

2011-01-01

The Moon offers a unique vantage point from which to investigate the Sun and its interaction via the solar wind magnetic fields, plasma, and energetic particles with the geospace system including the Moon itself. The lunar surface and exosphere provide in part a record of solar coronal plasma material input and resultant space weathering over billions of years. The structure and dynamics of solar wind interactions with the Moon provide an accessible near-Earth laboratory environment for study of general solar wind interactions with the vast multitude of airless asteroidal bodies of the inner solar system. Spacecraft in lunar orbit have the often simultaneous opportunity, except when in the Earth's magnetosphere, to make in-situ compositional measurements of the solar wind plasma and to carry out remote observations from the Moon of the solar corona, potentially enabled by lunar limb occultation of the solar disk. The LunaSOX project at NASA Goddard Space Flight Center is addressing these heliophysical science objectives from and of the Moon with support from NASA's Lunar Advanced Science and Exploration Research (LASER) program: (1) specify history of solar wind parameters at and sunward of the Moon through enhanced access (http://lunasox.gsfc.nasa.gov/) to legacy and operational mission data products from the Apollo era to the present, (2) model field and plasma interactions with the lunar surface, exosphere, and wake, as constrained by the available data, through hybrid kinetic code simulations, and (3) advance mission concepts for heliophysics from and of the Moon.

Computational modeling of joint U.S.-Russian experiments relevant to magnetic compression/magnetized target fusion (MAGO/MTF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheehey, P.T.; Faehl, R.J.; Kirkpatrick, R.C.

1997-12-31

Magnetized Target Fusion (MTF) experiments, in which a preheated and magnetized target plasma is hydrodynamically compressed to fusion conditions, present some challenging computational modeling problems. Recently, joint experiments relevant to MTF (Russian acronym MAGO, for Magnitnoye Obzhatiye, or magnetic compression) have been performed by Los Alamos National Laboratory and the All-Russian Scientific Research Institute of Experimental Physics (VNIIEF). Modeling of target plasmas must accurately predict plasma densities, temperatures, fields, and lifetime; dense plasma interactions with wall materials must be characterized. Modeling of magnetically driven imploding solid liners, for compression of target plasmas, must address issues such as Rayleigh-Taylor instability growthmore » in the presence of material strength, and glide plane-liner interactions. Proposed experiments involving liner-on-plasma compressions to fusion conditions will require integrated target plasma and liner calculations. Detailed comparison of the modeling results with experiment will be presented.« less

Innovative potential of plasma technology

NASA Astrophysics Data System (ADS)

Budaev, V. P.

2017-11-01

The review summarizes recent experimental observations of materials exposed to extreme hot plasma loads in fusion devices and plasma facilities with high-temperature plasma. Plasma load on the material in such devices lead to the stochastic clustering and fractal growth of the surface on scales from tens of nanometers to hundreds of micrometers forming statistical self-similarity of the surface roughness with extremely high specific area. Statistical characteristics of hierarchical granularity and scale invariance of such materials surface qualitatively differ from the properties of the roughness of the ordinary Brownian surface which provides a potential of innovative plasma technologies for synthesis of new nanostructured materials with programmed roughness properties, for hypersonic technologies, for biotechnology and biomedical applications.

Plasma-Powder Feedstock Interaction During Plasma Spray-Physical Vapor Deposition

NASA Astrophysics Data System (ADS)

Anwaar, Aleem; Wei, Lianglinag; Guo, Hongbo; Zhang, Baopeng

2017-02-01

Plasma spray-physical vapor deposition is a new process developed to produce coatings from the vapor phase. To achieve deposition from the vapor phase, the plasma-feedstock interaction inside the plasma torch, i.e., from the powder injection point to the nozzle exit, is critical. In this work, the plasma characteristics and the momentum and heat transfer between the plasma and powder feedstock at different torch input power levels were investigated theoretically to optimize the net plasma torch power, among other important factors such as the plasma gas composition, powder feed rate, and carrier gas. The plasma characteristics were calculated using the CEA2 code, and the plasma-feedstock interaction was studied inside the torch nozzle at low-pressure (20-25 kPa) conditions. A particle dynamics model was introduced to compute the particle velocity, coupled with Xi Chen's drag model for nonevaporating particles. The results show that the energy transferred to the particles and the coating morphology are greatly influenced by the plasma gas characteristics and the particle dynamics inside the nozzle. The heat transfer between the plasma gas and feedstock material increased with the net torch power up to an optimum at 64 kW, at which a maximum of 3.4% of the available plasma energy was absorbed by the feedstock powder. Experimental results using agglomerated 7-8 wt.% yttria-stabilized zirconia (YSZ) powder as feedstock material confirmed the theoretical predictions.

Recent advances in plasma modeling for space applications

NASA Astrophysics Data System (ADS)

Srinivasan, Bhuvana; Scales, Wayne; Cagas, Petr; Glesner, Colin

2017-02-01

This paper presents a brief overview of the application of advanced plasma modeling techniques to several space science and engineering problems currently of significant interest. Recent advances in both kinetic and fluid modeling provide the ability to study a wide variety of problems that may be important to space plasmas including spacecraft-environment interactions, plasma-material interactions for propulsion systems such as Hall thrusters, ionospheric plasma instabilities, plasma separation from magnetic nozzles, active space experiments, and a host of additional problems. Some of the key findings are summarized here.

Investigation of Plasma Facing Components in Plasma Focus Operation

NASA Astrophysics Data System (ADS)

Roshan, M. V.; Babazadeh, A. R.; Kiai, S. M. Sadat; Habibi, H.; Mamarzadeh, M.

2007-09-01

Both aspects of the plasma-wall interactions, counter effect of plasma and materials, have been considered in our experiments. The AEOI plasma focus, Dena, has Filippov-type electrodes. The experimental results verify that neutron production increases using tungsten as an anode insert material, compared to the copper one. The experiments show decrement of the hardness of Aluminum targets outward the sides, from 135 to 78 in Vickers scale. The sputtering yield is about 0.0065 for deuteron energy of 50 keV.

Research methods of plasma stream interaction with heat-resistant materials

NASA Astrophysics Data System (ADS)

Tyuftyaev, A. S.; Gadzhiev, M. Kh; Sargsyan, M. A.; Chinnov, V. F.; Demirov, N. A.; Kavyrshin, D. I.; Ageev, A. G.; Khromov, M. A.

2016-11-01

An experimental automated system was designed and constructed for studying the parameters and characteristics of non-stationary interacting system high-enthalpy-plasma stream-investigated sample: enthalpy of plasma in the incident stream; speed and temperature of plasma stream; temperature of electrons and heavy particles, ionic composition and their spatial distribution; heat flux incident on the sample (kW/cm2); surface temperature of the sample; ablation of the sample material, and others. Measurements of achievable plasma heat flux levels are carried out by calorimetry of plasma streams incident on the surface of multisection copper calorimeter. Determination of acceleration characteristics for profiled plasma torch nozzle, as well as the gas flow rate is produced by measuring the total pressure using the Pitot tube. Video visualization of interacting system is carried out using synchronized high-speed cameras. Micropyrometry of the selected zone on the sample surface is carried out by high-speed, three-wavelength pyrometer. To measure the rate of mass loss of the sample, in addition to the weighing method of evaluation the methods of laser knife and two-position stereoscopy are used. Plasma and sample emission characteristics are performed with two separate spectrometers.

Synthesis and design of silicide intermetallic materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrovic, J.J.; Castro, R.G.; Butt, D.P.

1997-04-01

The overall objective of this program is to develop structural silicide-based materials with optimum combinations of elevated temperature strength/creep resistance, low temperature fracture toughness, and high temperature oxidation and corrosion resistance for applications of importance to the U.S. processing industry. A further objective is to develop silicide-based prototype industrial components. The ultimate aim of the program is to work with industry to transfer the structural silicide materials technology to the private sector in order to promote international competitiveness in the area of advanced high temperature materials and important applications in major energy-intensive U.S. processing industries. The program presently has amore » number of developing industrial connections, including a CRADA with Schuller International Inc. targeted at the area of MoSi{sub 2}-based high temperature materials and components for fiberglass melting and processing applications. The authors are also developing an interaction with the Institute of Gas Technology (IGT) to develop silicides for high temperature radiant gas burner applications, for the glass and other industries. Current experimental emphasis is on the development and characterization of MoSi{sub 2}-Si{sub 3}N{sub 4} and MoSi{sub 2}-SiC composites, the plasma spraying of MoSi{sub 2}-based materials, and the joining of MoSi{sub 2} materials to metals.« less

Characterization of Atmospheric Pressure Plasma Torch and the Surface Interaction for Material Removal

NASA Astrophysics Data System (ADS)

McWilliams, Anthony Joseph

An atmospheric pressure plasma torch has been developed and characterized for removal of organic based coatings. The focus of the Strategic Environmental Research & Development Program (SERDP) project WP-1762, that funded the bulk of this dissertation work, is removal of paint from US Navy vessels. The goal is to develop a novel technology for coating removal that is capable of reducing the amount of environmental waste produced during the commonly used grit blasting process. The atmospheric pressure air plasma torch was identified as having the capacity to remove the paint systems while using only compressed air and electricity as a media-less removal system with drastically reduced waste generation. Any improvements to the existing technology need to be based on scientific knowledge and thus the plasma removal mechanisms or material warranted investigation. The removal of material does not show a strong relation to the plasma parameters of power, frequency, and gas flow, nor is there a strong relation to the presences of inorganic fillers impeding or altering the removal rates. The underlying removal mechanisms also do not show a strong correlation to the rotational temperature of the plasma but do show a strong correlation to the optical emission intensity. Primarily, the emission from atomic oxygen and molecular nitrogen were identified significant contributors and were investigated further. The plasma feed gas was then varied from the nitrogen and oxygen ratio present in ambient air to pure nitrogen to identify the effect of oxygen on the removal mechanism. From these experiments it was concluded that the oxygen present in air does contribute to the overall removal mechanism; however, it is not the sole contributing factor with the other major factor being nitrogen.

Plasma Protein Corona Modulates the Vascular Wall Interaction of Drug Carriers in a Material and Donor Specific Manner

PubMed Central

Sobczynski, Daniel J.; Charoenphol, Phapanin; Heslinga, Michael J.; Onyskiw, Peter J.; Namdee, Katawut; Thompson, Alex J.; Eniola-Adefeso, Omolola

2014-01-01

The nanoscale plasma protein interaction with intravenously injected particulate carrier systems is known to modulate their organ distribution and clearance from the bloodstream. However, the role of this plasma protein interaction in prescribing the adhesion of carriers to the vascular wall remains relatively unknown. Here, we show that the adhesion of vascular-targeted poly(lactide-co-glycolic-acid) (PLGA) spheres to endothelial cells is significantly inhibited in human blood flow, with up to 90% reduction in adhesion observed relative to adhesion in simple buffer flow, depending on the particle size and the magnitude and pattern of blood flow. This reduced PLGA adhesion in blood flow is linked to the adsorption of certain high molecular weight plasma proteins on PLGA and is donor specific, where large reductions in particle adhesion in blood flow (>80% relative to buffer) is seen with ∼60% of unique donor bloods while others exhibit moderate to no reductions. The depletion of high molecular weight immunoglobulins from plasma is shown to successfully restore PLGA vascular wall adhesion. The observed plasma protein effect on PLGA is likely due to material characteristics since the effect is not replicated with polystyrene or silica spheres. These particles effectively adhere to the endothelium at a higher level in blood over buffer flow. Overall, understanding how distinct plasma proteins modulate the vascular wall interaction of vascular-targeted carriers of different material characteristics would allow for the design of highly functional delivery vehicles for the treatment of many serious human diseases. PMID:25229244

Iodine Plasma (Electric Propulsion) Interaction with Spacecraft Materials

DTIC Science & Technology

2016-12-28

fairly resistant to the reactive iodine and iodine plasma . The tantalum heat shielding , though, does react with iodine. DISTRIBUTION A: Distribution...way coupling manner due to the disparate time scales between the electrons (10-10 s ) and plasma (10-3 s ).17,18 Exhaust particles were modeled in two... plasma iodine impacts/m2/ s . Figure 7: iSAT Plume Interaction4 The velocity of both the neutrals and ions impacting the surface will be relatively

Mission Integration Study for Solid Teflon Pulsed Plasma Millipound Propulsion System.

DTIC Science & Technology

1980-09-01

ADDRESSCOERE Air Foc IoktPouso abrtr 1 SD~kr8PIS reto o f Scegain and oSld Teyn Pulsedr A*S team s ona Pr o on rolling 181 87 -68 14. ONITRINGA N ~ (d~ff...57 4.3.3 Subsystem Impact Assessment .......... 63 4.4 Interactive Effects ....... ............... 671 4.4.1 Material Deposition on Spacecraft...Assessment ....... ... 127 5.4 Interactive Effects .... ................ .... 128 5.4.1 Material Deposition Requirements for Pulsed Plasma Thruster on DSP

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

NASA Astrophysics Data System (ADS)

Linke, J.

2006-04-01

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 R&D. 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.

The interaction of the near-field plasma with antennas used in magnetic fusion research

NASA Astrophysics Data System (ADS)

Caughman, John

2015-09-01

Plasma heating and current drive using antennas in the Ion Cyclotron Range of Frequencies (ICRF) are important elements for the success of magnetic fusion. The antennas must operate in a harsh environment, where local plasma densities can be >1018/m3, magnetic fields can range from 0.2-5 Tesla, and antenna operating voltages can be >40 kV. This environment creates operational issues due to the interaction of the near-field of the antenna with the local plasma. In addition to parasitic losses in this plasma region, voltage and current distributions on the antenna structure lead to the formation of high electric fields and RF plasma sheaths, which can lead to enhanced particle and energy fluxes on the antenna and on surfaces intersected by magnetic field lines connected to or passing near the antenna. These issues are being studied using a simple electrode structure and a single-strap antenna on the Prototype Materials Plasma EXperiment (Proto-MPEX) at ORNL, which is a linear plasma device that uses an electron Bernstein wave heated helicon plasma source to create a high-density plasma suitable for use in a plasma-material interaction test stand. Several diagnostics are being used to characterize the near-field interactions, including double-Langmuir probes, a retarding field energy analyzer, and optical emission spectroscopy. The RF electric field is being studied utilizing Dynamic Stark Effect spectroscopy and Doppler-Free Saturation Spectroscopy. Recent experimental results and future plans will be presented. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under Contract DE-AC-05-00OR22725.

Preliminary Results from the Flight of the Solar Array Module Plasma Interactions Experiment (SAMPIE)

NASA Technical Reports Server (NTRS)

Ferguson, Dale C.; Hillard, G. Barry

1994-01-01

SAMPIE, the Solar Array Module Plasma Interactions Experiment, flew in the Space Shuttle Columbia payload bay as part of the OAST-2 mission on STS-62, March, 1994. SAMPIE biased samples of solar arrays and space power materials to varying potentials with respect to the surrounding space plasma, and recorded the plasma currents collected and the arcs which occurred, along with a set of plasma diagnostics data. A large set of high quality data was obtained on the behavior of solar arrays and space power materials in the space environment. This paper is the first report on the data SAMPIE telemetered to the ground during the mission. It will be seen that the flight data promise to help determine arcing thresholds, snapover potentials and floating potentials for arrays and spacecraft in LEO.

Power Balance Analysis of the Prototype-Material Plasma Exposure eXperiment

NASA Astrophysics Data System (ADS)

Showers, M. A.; Biewer, T. M.; Caneses, J. F.; Caughman, J. B. O.; Lumsdaine, A.; Owen, L.; Rapp, J.; Youchison, D.; Beers, C. J.; Donovan, D. C.; Kafle, N.; Ray, H. B.

2017-10-01

The Prototype-Material Plasma Exposure eXperiment (Proto-MPEX) is a test bed for the plasma source concept for the planned Material Plasma Exposure eXperiment (MPEX), a steady-state linear device studying plasma material interactions for fusion reactors. A power balance of Proto-MPEX attempts to identify machine operating parameters that will improve Proto-MPEX's performance, potentially impacting the MPEX design concept. A power balance has been performed utilizing an extensive diagnostic suite to identify mechanisms and locations of power loss from the main plasma. The diagnostic package includes infrared cameras, double Langmuir probes, fluoroptic probes, Mach probes, a Thomson scattering diagnostic, a McPherson spectrometer and in-vessel thermocouples. Radiation losses are estimated with absolute calibrated spectroscopic signals. This work was supported by the U.S. D.O.E. contract DE-AC05-00OR22725.

US-Japan workshop Q-181 on high heat flux components and plasma-surface interactions for next devices: Proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGrath, R.T.; Yamashina, T.

This report contain viewgraphs of papers from the following sessions: plasma facing components issues for future machines; recent PMI results from several tokamaks; high heat flux technology; plasma facing components design and applications; plasma facing component materials and irradiation damage; boundary layer plasma; plasma disruptions; conditioning and tritium; and erosion/redeposition.

The efficacy of post porosity plasma protection against vacuum-ultraviolet damage in porous low-k materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lionti, K.; Volksen, W.; Darnon, M.

2015-03-21

As of today, plasma damage remains as one of the main challenges to the reliable integration of porous low-k materials into microelectronic devices at the most aggressive node. One promising strategy to limit damage of porous low-k materials during plasma processing is an approach we refer to as post porosity plasma protection (P4). In this approach, the pores of the low-k material are filled with a sacrificial agent prior to any plasma treatment, greatly minimizing the total damage by limiting the physical interactions between plasma species and the low-k material. Interestingly, the contribution of the individual plasma species to themore » total plasma damage is not fully understood. In this study, we investigated the specific damaging effect of vacuum-ultraviolet (v-UV) photons on a highly porous, k = 2.0 low-k material and we assessed the P4 protective effect against them. It was found that the impact of the v-UV radiation varied depending upon the v-UV emission lines of the plasma. More importantly, we successfully demonstrated that the P4 process provides excellent protection against v-UV damage.« less

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

PubMed

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.

EBW and Whistler propagation and damping in a linear device

NASA Astrophysics Data System (ADS)

Diem, S. J.; Caughman, J. B. O.; Harvey, R. W.; Petrov, Yu.

2011-10-01

Linear plasma devices are an economic method to study plasma-material interactions under high heat and particle fluxes. ORNL is developing a large cross section, high-density helicon plasma generator with additional resonant electron heating to study plasma-material interactions in ITER like conditions. The device will produce a heat flux of 10-20 MW/m2 and particle flux of 1024 /m2/s in a high recycling plasma near a target plate with a magnetic field of ~1 T. As part of this effort, heating of overdense plasma is being studied using a microwave-based plasma experiment. The plasma is initiated with a high-field launch of 18 GHz whistler waves producing a moderate-density plasma of ne ~1018 m-3. Electron heating of the overdense plasma can be provided by either whistler waves or EBW at 6 and 18 GHz. A modified GENRAY (GENRAY-C) ray-tracing code has been used to determine EBW and ECH whistler wave accessibility for these overdense plasmas. These results combined with emission measurements will be used to determine launcher designs and their placement. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC-05-00OR22725.

Liquid Metals as Plasma-facing Materials for Fusion Energy Systems: From Atoms to Tokamaks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, Howard A.; Koel, Bruce E.; Bernasek, Steven L.

The objective of our studies was to advance our fundamental understanding of liquid metals as plasma-facing materials for fusion energy systems, with a broad scope: from atoms to tokamaks. The flow of liquid metals offers solutions to significant problems of the plasma-facing materials for fusion energy systems. Candidate metals include lithium, tin, gallium, and their eutectic combinations. However, such liquid metal solutions can only be designed efficiently if a range of scientific and engineering issues are resolved that require advances in fundamental fluid dynamics, materials science and surface science. In our research we investigated a range of significant and timelymore » problems relevant to current and proposed engineering designs for fusion reactors, including high-heat flux configurations that are being considered by leading fusion energy groups world-wide. Using experimental and theoretical tools spanning atomistic to continuum descriptions of liquid metals, and bridging surface chemistry, wetting/dewetting and flow, our research has advanced the science and engineering of fusion energy materials and systems. Specifically, we developed a combined experimental and theoretical program to investigate flows of liquid metals in fusion-relevant geometries, including equilibrium and stability of thin-film flows, e.g. wetting and dewetting, effects of electromagnetic and thermocapillary fields on liquid metal thin-film flows, and how chemical interactions and the properties of the surface are influenced by impurities and in turn affect the surface wetting characteristics, the surface tension, and its gradients. Because high-heat flux configurations produce evaporation and sputtering, which forces rearrangement of the liquid, and any dewetting exposes the substrate to damage from the plasma, our studies addressed such evaporatively driven liquid flows and measured and simulated properties of the different bulk phases and material interfaces. The range of our studies included (i) quantum mechanical calculations that allow inclusion of many thousands of atoms for the characterization of the interface of liquid metals exposed to continuous bombardment by deuterium and tritium as expected in fusion, (ii) molecular dynamics studies of the phase behavior of liquid metals, which (a) utilize thermodynamic properties computed using our quantum mechanical calculations and (b) establish material and wetting properties of the liquid metals, including relevant eutectics, (iii) experimental investigations of the surface science of liquid metals, interacting both with the solid substrate as well as gaseous species, and (iv) fluid dynamical studies that incorporate the material and surface science results of (ii) and (iii) in order to characterize flow in capillary porous materials and the thin-film flow along curved boundaries, both of which are potentially major components of plasma-facing materials. The outcome of these integrated studies was new understanding that enables developing design rules useful for future developments of the plasma-facing components critical to the success of fusion energy systems.« less

Interactions of lectins with plasma membrane glycoproteins of the Ehrlich ascites carcinoma cell.

PubMed

Nachbar, M S; Oppenheim, J D; Aull, F

1976-02-06

Several aspects of the interaction of various lectins with the surface of Ehrlich ascites carcinoma cells are described. The order of agglutinating activity for various lectins is Ricinus communis greater than wheat germ greater than or equal to concanavalin A greater than or equal to soybean greater than Limulus polyphemus. No agglutination was noted for Ulex europaeus. Using 125I-labeled lectins it was determined that there are 1.6 and 7 times as many Ricinus communis lectin binding sites for concanavalin A and soybean lectins. Sodium deoxycholate-solubilized plasma membrane material was subjected to lectin affinity chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The lectin receptors of the plasma membrane appeared to be heterogeneous and some qualitative differences could be discerned among the electrophoretically analyzed material, which bound to and was specifically eluted from the various lectin affinity columns. The characteristics of elution of bound material from individual lectin columns indicated secondary hydrophobic interactions between concanavalin A or wheat germ agglutinin and their respective lectin receptor molecules.

Plasma Inter-Particle and Particle-Wall Interactions

NASA Astrophysics Data System (ADS)

Patino, Marlene Idy

An improved understanding of plasma inter-particle and particle-wall interactions is critical to the advancement of plasma devices used for space electric propulsion, fusion, high-power communications, and next-generation energy systems. Two interactions of particular importance are (1) ion-atom collisions in the plasma bulk and (2) secondary electron emission from plasma-facing materials. For ion-atom collisions, interactions between fast ions and slow atoms are commonly dominated by charge-exchange and momentum-exchange collisions that are important to understanding the performance and behavior of many plasma devices. To investigate this behavior, this work developed a simple, well-characterized experiment that accurately measures the effects of high energy xenon ions incident on a background of xenon neutral atoms. By comparing these results to both analytical and computational models of ion-atom interactions, we discovered the importance of (1) accurately treating the differential cross-sections for momentum-exchange and charge-exchange collisions over all neutral background pressures, and (2) commonly overlooked interactions, including ion-induced electron emission and neutral-neutral ionization collisions, at high pressures. Data provide vital information on the angular scattering distributions of charge-exchange and momentum-exchange ions at 1.5 keV relevant for ion thrusters, and serve as canonical data for validation of plasma models. This work also investigates electron-induced secondary electron emission behavior relevant to materials commonly considered for plasma thrusters, fusion systems, and many other plasma devices. For such applications, secondary electron emission can alter the sheath potential, which can significantly affect device performance and life. Secondary electron emission properties were measured for materials that are critical to the efficient operation of many plasma devices, including: graphite (for tokamaks, ion thrusters, and traveling wave tubes), lithium (for tokamak walls), tungsten (the most promising material for future tokamaks such as ITER), and nickel (for plasma-enhanced chemistry). Measurements were made for incident electron energies up to 1.5 keV and angles between 0 and 78°. The most significant results from these measurements are as follows: (1) first-ever measurements of naturally-forming tungsten fuzz show a more than 40% reduction in secondary electron emission and an independence on incidence angle; (2) original measurements of lithium oxide show a 2x and 6x increase in secondary electron emission for 17% and 100% oxidation; and (3) unique measurements of Ni(110) single crystal show extrema in secondary electron emission when incidence angle is varied and an up to 36% increase at 0° over polycrystalline nickel. Each of these results are important discoveries for improving plasma devices. For example, from (1), the growth of tungsten fuzz in tokamaks is desirable for minimizing adverse secondary electron emission effects. From (2), the opposite is true for tokamaks with lithium coatings which are oxidized by typical residual gases. From (3), secondary electron emission from Ni(110) catalysts in plasma-enhanced chemistry may facilitate further reactions.

Plasma-surface interaction in the Be/W environment: Conclusions drawn from the JET-ILW for ITER

NASA Astrophysics Data System (ADS)

Brezinsek, S.; JET-EFDA contributors

2015-08-01

The JET ITER-Like Wall experiment (JET-ILW) provides an ideal test bed to investigate plasma-surface interaction (PSI) and plasma operation with the ITER plasma-facing material selection employing beryllium in the main chamber and tungsten in the divertor. The main PSI processes: material erosion and migration, (b) fuel recycling and retention, (c) impurity concentration and radiation have be1en studied and compared between JET-C and JET-ILW. The current physics understanding of these key processes in the JET-ILW revealed that both interpretation of previously obtained carbon results (JET-C) and predictions to ITER need to be revisited. The impact of the first-wall material on the plasma was underestimated. Main observations are: (a) low primary erosion source in H-mode plasmas and reduction of the material migration from the main chamber to the divertor (factor 7) as well as within the divertor from plasma-facing to remote areas (factor 30 - 50). The energetic threshold for beryllium sputtering minimises the primary erosion source and inhibits multi-step re-erosion in the divertor. The physical sputtering yield of tungsten is low as 10-5 and determined by beryllium ions. (b) Reduction of the long-term fuel retention (factor 10 - 20) in JET-ILW with respect to JET-C. The remaining retention is caused by implantation and co-deposition with beryllium and residual impurities. Outgassing has gained importance and impacts on the recycling properties of beryllium and tungsten. (c) The low effective plasma charge (Zeff = 1.2) and low radiation capability of beryllium reveal the bare deuterium plasma physics. Moderate nitrogen seeding, reaching Zeff = 1.6 , restores in particular the confinement and the L-H threshold behaviour. ITER-compatible divertor conditions with stable semi-detachment were obtained owing to a higher density limit with ILW. Overall JET demonstrated successful plasma operation in the Be/W material combination and confirms its advantageous PSI behaviour and gives strong support to the ITER material selection.

Method and system for nanoscale plasma processing of objects

DOEpatents

Oehrlein, Gottlieb S [Clarksville, MD; Hua, Xuefeng [Hyattsville, MD; Stolz, Christian [Baden-Wuerttemberg, DE

2008-12-30

A plasma processing system includes a source of plasma, a substrate and a shutter positioned in close proximity to the substrate. The substrate/shutter relative disposition is changed for precise control of substrate/plasma interaction. This way, the substrate interacts only with a fully established, stable plasma for short times required for nanoscale processing of materials. The shutter includes an opening of a predetermined width, and preferably is patterned to form an array of slits with dimensions that are smaller than the Debye screening length. This enables control of the substrate/plasma interaction time while avoiding the ion bombardment of the substrate in an undesirable fashion. The relative disposition between the shutter and the substrate can be made either by moving the shutter or by moving the substrate.

Preliminary results from the flight of the Solar Array Module Plasma Interactions Experiment (SAMPIE)

NASA Technical Reports Server (NTRS)

Ferguson, Dale C.; Hillard, G. Barry

1994-01-01

SAMPIE, the Solar Array Module Plasma Interactions Experiment, flew in the Space Shuttle Columbia payload bay as part of the Office of Aeronautics and Space Technology-2 (OAST-2) mission on STS-62, March, 1994. SAMPIE biased samples of solar arrays and space power materials to varying potentials with respect to the surrounding space plasma, and recorded the plasma currents collected and the arcs which occurred, along with a set of plasma diagnostics data. A large set of high quality data was obtained on the behavior of solar arrays and space power materials in the space environment. This paper is the first report on the data SAMPIE telemetered to the ground during the mission. It will be seen that the flight data promise to help determine arcing thresholds, snapover potentials, and floating potentials for arrays and spacecraft in LEO.

A dual wavelength imaging system for plasma-surface interaction studies on the National Spherical Torus Experiment Upgrade

DOE PAGES

Scotti, F.; Soukhanovskii, V. A.

2015-12-09

A two-channel spectral imaging system based on a charge injection device radiation-hardened intensified camera was built for studies of plasma-surface interactions on divertor plasma facing components in the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak. By means of commercially available mechanically referenced optical components, the two-wavelength setup images the light from the plasma, relayed by a fiber optic bundle, at two different wavelengths side-by-side on the same detector. Remotely controlled filter wheels are used for narrow band pass and neutral density filters on each optical path allowing for simultaneous imaging of emission at wavelengths differing in brightness up to 3more » orders of magnitude. Applications on NSTX-U will include the measurement of impurity influxes in the lower divertor strike point region and the imaging of plasma-material interaction on the head of the surface analysis probe MAPP (Material Analysis and Particle Probe). Furthermore, the diagnostic setup and initial results from its application on the lithium tokamak experiment are presented.« less

Spatial-temporal diagnostics of the system of a plasma stream interacting with a surface of heat resistant material

NASA Astrophysics Data System (ADS)

Chinnov, V. F.; Sargsyan, M. A.; Gadzhiev, M. Kh; Khromov, M. A.; Kavyrshin, D. I.; Chistolinov, A. V.

2018-01-01

In an automated measuring complex using optical and spectral methods the spatial and temporal changes in the parameters and composition of nitrogen plasma jet were investigated. The plasma jet was flowing out of the nozzle of the plasma torch with 10-12 kK temperature and acting on the sample of MPG-6 graphite. Due to the heating of the sample to the temperatures of 2.5-3 kK the influence of the sublimating material of the sample on the plasma composition and temperature in the near-surface region of the sample was investigated. An original method based on the analysis of movement of optical inhomogeneities in the plasma flow was used to estimate the plasma jet velocity in the region where it interacts with the sample. The combined analysis of the results of two-positioning video recordings opens up the possibility of determining spatial-temporal distributions of the plasma jet velocities, in medium and high pressure environments, in the ranges from few to thousands of m/s and 3-15 kK temperatures.

Real-time and post-plasma studies of influence of low levels of tungsten on carbon erosion and surface evolution behaviour in D2 plasma

NASA Astrophysics Data System (ADS)

Weilnboeck, F.; Fox-Lyon, N.; Oehrlein, G. S.; Doerner, R. P.

2010-02-01

A profound influence of monolayer tungsten coverage of hard carbon films on the evolution of carbon surface erosion behaviour, surface chemistry and morphology in D2 plasma has been established by real-time ellipsometry, x-ray photoelectron spectroscopy and atomic force microscopy measurements. The erosion of tungsten-covered carbon showed two distinct stages of plasma material interactions: rapid tungsten removal during the initial erosion period and steady-state amorphous carbon removal accompanied by large-scale surface roughness development. The initial removal of tungsten takes place at a rate that significantly exceeds typical sputter yields at the ion energies used here and is attributed to elimination of weakly bonded tungsten from the surface. The tungsten remaining on the a-C : H film surface causes surface roughness development of the eroding carbon surface by a masking effect, and simultaneously leads to a seven fold reduction of the steady-state carbon erosion rate for long plasma surface interaction times (~100 s). Results presented are of direct relevance for material transport and re-deposition, and the interaction of those films with plasma in the divertor region and on mirror surfaces of fusion devices.

An assessment of surface emissivity variation effects on plasma uniformity analysis using IR cameras

NASA Astrophysics Data System (ADS)

Greenhalgh, Abigail; Showers, Melissa; Biewer, Theodore

2017-10-01

The Prototype-Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma device operating at Oak Ridge National Laboratory (ORNL). Its purpose is to test plasma source and heating concepts for the planned Material Plasma Exposure eXperiment (MPEX), which has the mission to test the plasma-material interactions under fusion reactor conditions. In this device material targets will be exposed to high heat fluxes (>10 MW/m2). To characterize the heat fluxes to the target a IR thermography system is used taking up to 432 frames per second videos. The data is analyzed to determine the surface temperature on the target in specific regions of interest. The IR analysis has indicated a low level of plasma uniformity; the plasma often deposits more heat to the edge of the plate than the center. An essential parameter for IR temperature calculation is the surface emissivity of the plate (stainless steel). A study has been performed to characterize the variation in the surface emissivity of the plate as its temperature changes and its surface finish is modified by plasma exposure.

Plasma of argon enhances the adhesion of murine osteoblasts on different graft materials.

PubMed

Canullo, Luigi; Genova, Tullio; Naenni, Nadja; Nakajima, Yasushi; Masuda, Katsuhiko; Mussano, Federico

2018-04-25

plasma of argon treatment was demonstrated to increase material surface energy leading to stronger and faster interaction with cells. The aim of the present in vitro study was to test the effect of plasma treatment on different graft materials. synthetic hydroxyapatite (Mg-HA), biphasic calcium phosphate (BCP), cancellous and cortical xenogeneic bone matrices (CaBM, CoBM) were used representing commonly used classes of bone substitute materials. Fifty serially numbered disks with a 10mm-diameter from each graft material were randomly divided into two groups: Test group (argon plasma treatment) and Control group (absence of treatment). Cell morphology (using pre-osteoblastic murine cells) and protein adsorption were analyzed at all samples from both the test and control group. Differences between groups were analyzed using the Mann-Whitney test setting the level of significance at p<0.05. plasma treatment significantly increased the protein adsorption at all samples. Similarly, plasma treatment significantly increased cell adhesion in all groups. data confirmed that non-atmospheric plasma of argon treatment led to an increase of protein adsorption and cell adhesion in all groups of graft material to a similar extent. plasma of argon is able to improve the surface conditions of graft materials. Copyright © 2018 Elsevier GmbH. All rights reserved.

Plasma chamber testing of advanced photovoltaic solar array coupons

NASA Technical Reports Server (NTRS)

Hillard, G. Barry

1994-01-01

The solar array module plasma interactions experiment is a space shuttle experiment designed to investigate and quantify the high voltage plasma interactions. One of the objectives of the experiment is to test the performance of the Advanced Photovoltaic Solar Array (APSA). The material properties of array blanket are also studied as electric insulators for APSA arrays in high voltage conditions. Three twelve cell prototype coupons of silicon cells were constructed and tested in a space simulation chamber.

Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

NASA Astrophysics Data System (ADS)

Lu, X.; Naidis, G. V.; Laroussi, M.; Reuter, S.; Graves, D. B.; Ostrikov, K.

2016-05-01

Non-equilibrium atmospheric-pressure plasmas have recently become a topical area of research owing to their diverse applications in health care and medicine, environmental remediation and pollution control, materials processing, electrochemistry, nanotechnology and other fields. This review focuses on the reactive electrons and ionic, atomic, molecular, and radical species that are produced in these plasmas and then transported from the point of generation to the point of interaction with the material, medium, living cells or tissues being processed. The most important mechanisms of generation and transport of the key species in the plasmas of atmospheric-pressure plasma jets and other non-equilibrium atmospheric-pressure plasmas are introduced and examined from the viewpoint of their applications in plasma hygiene and medicine and other relevant fields. Sophisticated high-precision, time-resolved plasma diagnostics approaches and techniques are presented and their applications to monitor the reactive species and plasma dynamics in the plasma jets and other discharges, both in the gas phase and during the plasma interaction with liquid media, are critically reviewed. The large amount of experimental data is supported by the theoretical models of reactive species generation and transport in the plasmas, surrounding gaseous environments, and plasma interaction with liquid media. These models are presented and their limitations are discussed. Special attention is paid to biological effects of the plasma-generated reactive oxygen and nitrogen (and some other) species in basic biological processes such as cell metabolism, proliferation, survival, etc. as well as plasma applications in bacterial inactivation, wound healing, cancer treatment and some others. Challenges and opportunities for theoretical and experimental research are discussed and the authors' vision for the emerging convergence trends across several disciplines and application domains is presented to stimulate critical discussions and collaborations in the future.

Studying Spacecraft Charging via Numerical Simulations

NASA Astrophysics Data System (ADS)

Delzanno, G. L.; Moulton, D.; Meierbachtol, C.; Svyatskiy, D.; Vernon, L.

2015-12-01

The electrical charging of spacecraft due to bombarding charged particles can affect their performance and operation. We study this charging using CPIC; a particle-in-cell code specifically designed for studying plasma-material interactions [1]. CPIC is based on multi-block curvilinear meshes, resulting in near-optimal computational performance while maintaining geometric accuracy. Relevant plasma parameters are imported from the SHIELDS framework (currently under development at LANL), which simulates geomagnetic storms and substorms in the Earth's magnetosphere. Simulated spacecraft charging results of representative Van Allen Probe geometries using these plasma parameters will be presented, along with an overview of the code. [1] G.L. Delzanno, E. Camporeale, J.D. Moulton, J.E. Borovsky, E.A. MacDonald, and M.F. Thomsen, "CPIC: A Curvilinear Particle-In-Cell Code for Plasma-Material Interaction Studies," IEEE Trans. Plas. Sci., 41 (12), 3577 (2013).

EDITORIAL: Plasma Surface Interactions for Fusion

NASA Astrophysics Data System (ADS)

2006-05-01

Because plasma-boundary physics encompasses some of the most important unresolved issues for both the International Thermonuclear Experimental Reactor (ITER) project and future fusion power reactors, there is a strong interest in the fusion community for better understanding and characterization of plasma wall interactions. Chemical and physical sputtering cause the erosion of the limiters/divertor plates and vacuum vessel walls (made of C, Be and W, for example) and degrade fusion performance by diluting the fusion fuel and excessively cooling the core, while carbon redeposition could produce long-term in-vessel tritium retention, degrading the superior thermo-mechanical properties of the carbon materials. Mixed plasma-facing materials are proposed, requiring optimization for different power and particle flux characteristics. Knowledge of material properties as well as characteristics of the plasma material interaction are prerequisites for such optimizations. Computational power will soon reach hundreds of teraflops, so that theoretical and plasma science expertise can be matched with new experimental capabilities in order to mount a strong response to these challenges. To begin to address such questions, a Workshop on New Directions for Advanced Computer Simulations and Experiments in Fusion-Related Plasma Surface Interactions for Fusion (PSIF) was held at the Oak Ridge National Laboratory from 21 to 23 March, 2005. The purpose of the workshop was to bring together researchers in fusion related plasma wall interactions in order to address these topics and to identify the most needed and promising directions for study, to exchange opinions on the present depth of knowledge of surface properties for the main fusion-related materials, e.g., C, Be and W, especially for sputtering, reflection, and deuterium (tritium) retention properties. The goal was to suggest the most important next steps needed for such basic computational and experimental work to be facilitated by researchers in fusion, material, and physical sciences. Representatives from many fusion research laboratories attended, and 25 talks were given, the majority of them making up the content of these Workshop proceedings. The presentations of all talks and further information on the Workshop are available at http://www-cfadc.phy.ornl.gov/psif/home.html. The workshop talks dealt with identification of needs from the perspective of integrated fusion simulation and ITER design, recent developments and perspectives on computation of plasma-facing surface properties using the current and expected new generation of computation capability, and with the status of dedicated laboratory experiments which characterize the underlying processes of PSIF. The Workshop summary and conclusions are being published in Nuclear Fusion 45 (2005). We are indebted to Lynda Saddiq and Fay Ownby, secretaries in the Physics Division of ORNL, whose special efforts, devotion, and expertise made possible both the Workshop and these Proceedings. J T Hogan, P S Krstic and F W Meyer Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372, USA

Lunar interactions: Abstracts of papers presented at the Conference on Interactions of the Interplanetary Plasma with the Modern and Ancient Moon

NASA Technical Reports Server (NTRS)

Criswell, D. R. (Editor); Freeman, J. W. (Editor)

1974-01-01

Reviewed are the active mechanisms relating the moon to its environment and the linkage between these mechanisms and their records in the lunar sample and geophysical data. Topics: (1) large scale plasma interactions with the moon and non-magnetic planets; (2) ancient and present day lunar surface magnetic and electric fields; (3) dynamics and evolution of the lunar atmosphere; (4) evolution of the solar plasma; (5) lunar record of solar radiations; (6) non-meteoritic and meteoritic disturbance and transport of lunar surface materials; and (7) future lunar exploration.

Foundations of low-temperature plasma enhanced materials synthesis and etching

NASA Astrophysics Data System (ADS)

Oehrlein, Gottlieb S.; Hamaguchi, Satoshi

2018-02-01

Low temperature plasma (LTP)-based synthesis of advanced materials has played a transformational role in multiple industries, including the semiconductor industry, liquid crystal displays, coatings and renewable energy. Similarly, the plasma-based transfer of lithographically defined resist patterns into other materials, e.g. silicon, SiO2, Si3N4 and other electronic materials, has led to the production of nanometer scale devices that are the basis of the information technology, microsystems, and many other technologies based on patterned films or substrates. In this article we review the scientific foundations of both LTP-based materials synthesis at low substrate temperature and LTP-based isotropic and directional etching used to transfer lithographically produced resist patterns into underlying materials. We cover the fundamental principles that are the basis of successful application of the LTP techniques to technological uses and provide an understanding of technological factors that may control or limit material synthesis or surface processing with the use of LTP. We precede these sections with a general discussion of plasma surface interactions, the LTP-generated particle fluxes including electrons, ions, radicals, excited neutrals and photons that simultaneously contact and modify surfaces. The surfaces can be in the line of sight of the discharge or hidden from direct interaction for structured substrates. All parts of the article are extensively referenced, which is intended to help the reader study the topics discussed here in more detail.

Progress in the Development of a High Power Helicon Plasma Source for the Materials Plasma Exposure Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goulding, Richard Howell; Caughman, John B.; Rapp, Juergen

Proto-MPEX is a linear plasma device being used to study a novel RF source concept for the planned Material Plasma Exposure eXperiment (MPEX), which will address plasma-materials interaction (PMI) for nuclear fusion reactors. Plasmas are produced using a large diameter helicon source operating at a frequency of 13.56 MHz at power levels up to 120 kW. In recent experiments the helicon source has produced deuterium plasmas with densities up to ~6 × 1019 m–3 measured at a location 2 m downstream from the antenna and 0.4 m from the target. Previous plasma production experiments on Proto-MPEX have generated lower densitymore » plasmas with hollow electron temperature profiles and target power deposition peaked far off axis. The latest experiments have produced flat Te profiles with a large portion of the power deposited on the target near the axis. This and other evidence points to the excitation of a helicon mode in this case.« less

Nanostructured materials: A novel approach to enhanced performance. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korth, G.E.; Froes, F.H.; Suryanarayana, C.

Nanostuctured materials are an emerging class of materials that can exhibit physical and mechanical characteristics often exceeding those exhibited by conventional course grained materials. A number of different techniques can be employed to produce these materials. In this program, the synthesis methods were (a) mechanical alloying , (b) physical vapor deposition, and (c) plasma processing. The physical vapor deposition and plasma processing were discontinued after initial testing with subsequent efforts focused on mechanical alloying. The major emphasis of the program was on the synthesis, consolidation, and characterization of nanostructured Al-Fe, Ti-Al, Ti-Al-Nb, and Fe-Al by alloying intermetallics with a viewmore » to increase their ductilities. The major findings of this project are reported.« less

Plasma-Facing Component and Materials Testing for the NSTX-U

NASA Astrophysics Data System (ADS)

Jaworski, Michael; Brooks, A.; Gerhardt, S.; Loesser, D.; Mardenfeld, M.; Menard, J.; Gray, T.; Reinke, M.

2017-10-01

The NSTX-U Recovery Project is developing plasma-facing components for use in the divertor of NSTX-U. The extreme conditions of the NSTX-U divertor make it possible to stress even graphite surfaces to the material limits leading to the possibility of component failures. In addition, the complex, mixed-material environment of the NSTX-U due to the use of boron and lithium wall conditioning techniques creates significant uncertainties in the monitoring of the PFCs. A testing program has been developed to inform on the material and design limitations of the NSTX-U high-heat flux components. These tests include high-heat flux testing in electron beam facilities as well as plasma-based testing. The NSTX-U components could experience perpendicular heat fluxes as high as 45 MW/m2. Parallel heat fluxes onto leading edges could reach 475 MW/m2. The testing program and material survey plan will be presented. Work supported by DOE contract DE-AC02-09CH11466 and DE-AC05-00OR22725.

Development of tungsten armor and bonding to copper for plasma-interactive components

NASA Astrophysics Data System (ADS)

Smid, I.; Akiba, M.; Vieider, G.; Plöchl, L.

1998-10-01

For the highest sputtering threshold of all possible candidates, tungsten will be the most likely armor material in highly loaded plasma-interactive components of commercially relevant fusion reactors. The development of new materials, as well as joining and coating techniques are needed to find the best balance in plasma compatibility, lifetime, reliability, neutron irradiation resistance, and safety. Further important issues for selection are availability, costs of machining and production, etc. Tungsten doped with lanthanum oxide is a commercially available W grade for electrodes, designed for low electron work function, higher recrystallization temperature, reduced secondary grain growth, and machinability at relatively low costs. W-Re and related tungsten base alloys are preferred for application at high temperatures, when high strength, high thermal shock and recrystallization resistance are required. Due to the high costs and limited global availability of Re, however, the amount of such alloys in a commercial reactor should be kept low. Newly measured material properties up to high temperatures are presented for lanthanated and W-Re alloys, and the impact on fusion application is discussed. Recently developed coatings of chemical vapor deposited tungsten (CVD-W) on copper substrates have proven to be resistant to repeated thermal and shock loading. Layers of more than 5 mm, as required for the International Thermonuclear Experimental Reactor (ITER), became available. Vacuum plasma sprayed tungsten (VPS-W) in particular is attractive for its lower costs, and the potential of in situ repair. However, the advantage of sacrificial plasma-interactive tungsten coatings in long-term fusion devices has yet to be demonstrated. A durable and reliable joining of bulk tungsten to copper is needed to achieve an acceptable component lifetime in a fusion environment. The material properties of the copper alloys proposed for ITER, and their impact on the quality of bonding to tungsten is discussed. Future materials R&D should concern issues such as plasma compatibility, and above all neutron irradiation damage of promising tungsten-copper joints.

Simulation of plasma-surface interactions in a fusion reactor by means of QSPA plasma streams: recent results and prospects

NASA Astrophysics Data System (ADS)

Garkusha, I. E.; Aksenov, N. N.; Byrka, O. V.; Makhlaj, V. A.; Herashchenko, S. S.; Malykhin, S. V.; Petrov, Yu V.; Staltsov, V. V.; Surovitskiy, S. V.; Wirtz, M.; Linke, J.; Sadowski, M. J.; Skladnik-Sadowska, E.

2016-09-01

This paper is devoted to plasma-surface interaction issues at high heat-loads which are typical for fusion reactors. For the International Thermonuclear Experimental Reactor (ITER), which is now under construction, the knowledge of erosion processes and the behaviour of various constructional materials under extreme conditions is a very critical issue, which will determine a successful realization of the project. The most important plasma-surface interaction (PSI) effects in 3D geometry have been studied using a QSPA Kh-50 powerful quasi-stationary plasma accelerator. Mechanisms of the droplet and dust generation have been investigated in detail. It was found that the droplets emission from castellated surfaces has a threshold character and a cyclic nature. It begins only after a certain number of the irradiating plasma pulses when molten and shifted material is accumulated at the edges of the castellated structure. This new erosion mechanism, connected with the edge effects, results in an increase in the size of the emitted droplets (as compared with those emitted from a flat surface). This mechanism can even induce the ejection of sub-mm particles. A concept of a new-generation QSPA facility, the current status of this device maintenance, and prospects for further experiments are also presented.

BCA-kMC Hybrid Simulation for Hydrogen and Helium Implantation in Material under Plasma Irradiation

NASA Astrophysics Data System (ADS)

Kato, Shuichi; Ito, Atsushi; Sasao, Mamiko; Nakamura, Hiroaki; Wada, Motoi

2015-09-01

Ion implantation by plasma irradiation into materials achieves the very high concentration of impurity. The high concentration of impurity causes the deformation and the destruction of the material. This is the peculiar phenomena in the plasma-material interaction (PMI). The injection process of plasma particles are generally simulated by using the binary collision approximation (BCA) and the molecular dynamics (MD), while the diffusion of implanted atoms have been traditionally solved by the diffusion equation, in which the implanted atoms is replaced by the continuous concentration field. However, the diffusion equation has insufficient accuracy in the case of low concentration, and in the case of local high concentration such as the hydrogen blistering and the helium bubble. The above problem is overcome by kinetic Monte Carlo (kMC) which represents the diffusion of the implanted atoms as jumps on interstitial sites in a material. In this paper, we propose the new approach ``BCA-kMC hybrid simulation'' for the hydrogen and helium implantation under the plasma irradiation.

Plasma Jet Interactions with Liquids in Partial Fulfillment of an NRL Karles Fellowship

DTIC Science & Technology

2015-11-30

deposition), modify (e.g., chemical functionalization), and etch (in Si technology) materials. In low- pressure non- equilibrium discharge plasmas... equilibrium discharge plasmas, associated with the above processes, the electron population is much more energetic than both the ions and neutral gas...to be crucial to the advancements of these fields1, 2. Background: Atmospheric-pressure, non- equilibrium (APNE) plasmas, like low-pressure plasmas

A Comparison of Atomic Oxygen Degradation in Low Earth Orbit and in a Plasma Etcher

NASA Technical Reports Server (NTRS)

Townsend, Jacqueline A.; Park, Gloria

1997-01-01

In low Earth orbit (LEO) significant degradation of certain materials occurs from exposure to atomic oxygen (AO). Orbital opportunities to study this degradation for specific materials are limited and expensive. While plasma etchers are commonly used in ground-based studies because of their low cost and convenience, the environment produced in an etcher chamber differs greatly from the LEO environment. Because of the differences in environment, the validity of using etcher data has remained an open question. In this paper, degradation data for 22 materials from the orbital experiment Evaluation of Oxygen Interaction with Materials (EOIM-3) are compared with data from EOIM-3 control specimens exposed in a typical plasma etcher. This comparison indicates that, when carefully considered, plasma etcher results can produce order-of-magnitude estimates of orbital degradation. This allows the etcher to be used to screen unacceptable materials from further, more expensive tests.

A research program in magnetogasdynamics utilizing hypervelocity coaxial plasma generators

NASA Technical Reports Server (NTRS)

Spight, C.

1976-01-01

A broadly-gauged research program in magnetogasdynamics utilizing hypervelocity coaxial plasma generators is presented. A complete hypervelocity coaxial plasma generator facility was assembled and tested. Significant progress was made in the direction of understanding the important processes in the interaction of hypervelocity MGD flow with transverse applied fields. It is now proposed to utilize the accumulated experimental capability and theoretical analysis in application to the analysis and design parameterization of pulsed magnetogasdynamic direct energy convertor configurations.

Computation of Electron Impact Ionization Cross sections of Iron Hydrogen Clusters - Relevance in Fusion Plasmas

NASA Astrophysics Data System (ADS)

Patel, Umang; Joshipura, K. N.

2017-04-01

Plasma-wall interaction (PWI) is one of the key issues in nuclear fusion research. In nuclear fusion devices, such as the JET tokamak or the ITER, first-wall materials will be directly exposed to plasma components. Erosion of first-wall materials is a consequence of the impact of hydrogen and its isotopes as main constituents of the hot plasma. Besides the formation of gas-phase atomic species in various charge states, di- and polyatomic molecular species are expected to be formed via PWI processes. These compounds may profoundly disturb the fusion plasma, may lead to unfavorable re-deposition of materials and composites in other areas of the vessel. Interaction between atoms, molecules as well transport of impurities are of interest for modelling of fusion plasma. Qion by electron impact are such process also important in low temperature plasma processing, astrophysics etc. We reported electron impact Qionfor iron hydrogen clusters, FeHn (n = 1 to 10) from ionization threshold to 2000 eV. A semi empirical approach called Complex Scattering Potential - Ionization Contribution (CSP-ic) has been employed for the reported calculation. In context of fusion relevant species Qion were reported for beryllium and its hydrides, tungsten and its oxides and cluster of beryllium-tungsten by Huber et al.. Iron hydrogen clusters are another such species whose Qion were calculated through DM and BEB formalisms, same has been compared with present calculations.

Analysis of plasma particle and energy fluxes to material surfaces from tokamak edge turbulence simulations

NASA Astrophysics Data System (ADS)

Umansky, M. V.; Cohen, B. I.; Rognlien, T. D.; Boedo, J. A.; Rudakov, D. L.

2012-10-01

Recent BOUT simulations of edge plasma turbulence in L-mode regime in the boundary region of DIII-D tokamak have demonstrated reasonable match with key edge diagnostics [1]. Order-of-magnitude level agreement has been found in the characteristic amplitude, wavenumber, and frequency of turbulent fluctuations, as compared with experimental data from reciprocating edge Langmuir probe and Beam Emission Spectroscopy systems. Owing to this encouraging agreement, output data from these simulations are analyzed to get insights on physical mechanisms and properties of plasma particle and energy fluxes to material surfaces. Of particular interest is plasma turbulence propagating into, or generated in, the far scrape-off layer region where plasma interacts with material walls. Results of statistical analyses of simulated turbulence plasma transport will be presented and physical implications will be discussed. [4pt] [1] B.I. Cohen et al., APS-DPP 2012

Progress in magnet design activities for the material plasma exposure experiment

DOE PAGES

Duckworth, Robert; Lumsdaine, Arnold; Rapp, Juergen; ...

2017-07-01

One of the critical challenges for the development of next generation fusion facilities, such as a Fusion Nuclear Science Facility (FNSF) or DEMO, is the understanding of plasma material interactions (PMI). Making progress in PMI research will require integrated facilities that can provide the types of conditions that will be seen in the first wall and divertor regions of future fusion facilities. In order to meet this need, a new linear plasma facility, the Materials Plasma Exposure Experiment (MPEX), is proposed. In order to generate high ion fluence to simulate fusion divertor conditions, a steady-state plasma will be generated andmore » confined with superconducting magnets. Finally, the on-axis fields will range from 1 to 2.5 T in order to meet the requirements of the various plasma source and heating systems. Details on the pre-conceptual design of the magnets and cryogenic system are presented.« less

Metabolite profiling of a NIST Standard Reference Material for human plasma (SRM 1950): GC-MS, LC-MS, NMR, and clinical laboratory analyses, libraries, and web-based resources.

PubMed

Simón-Manso, Yamil; Lowenthal, Mark S; Kilpatrick, Lisa E; Sampson, Maureen L; Telu, Kelly H; Rudnick, Paul A; Mallard, W Gary; Bearden, Daniel W; Schock, Tracey B; Tchekhovskoi, Dmitrii V; Blonder, Niksa; Yan, Xinjian; Liang, Yuxue; Zheng, Yufang; Wallace, William E; Neta, Pedatsur; Phinney, Karen W; Remaley, Alan T; Stein, Stephen E

2013-12-17

Recent progress in metabolomics and the development of increasingly sensitive analytical techniques have renewed interest in global profiling, i.e., semiquantitative monitoring of all chemical constituents of biological fluids. In this work, we have performed global profiling of NIST SRM 1950, "Metabolites in Human Plasma", using GC-MS, LC-MS, and NMR. Metabolome coverage, difficulties, and reproducibility of the experiments on each platform are discussed. A total of 353 metabolites have been identified in this material. GC-MS provides 65 unique identifications, and most of the identifications from NMR overlap with the LC-MS identifications, except for some small sugars that are not directly found by LC-MS. Also, repeatability and intermediate precision analyses show that the SRM 1950 profiling is reproducible enough to consider this material as a good choice to distinguish between analytical and biological variability. Clinical laboratory data shows that most results are within the reference ranges for each assay. In-house computational tools have been developed or modified for MS data processing and interactive web display. All data and programs are freely available online at http://peptide.nist.gov/ and http://srmd.nist.gov/ .

An experimental investigation of rubbing interaction in labyrinth seals at cryogenic temperature

NASA Technical Reports Server (NTRS)

Dolan, F. X.; Kennedy, F. E.; Schulson, E. M.

1985-01-01

An experimental program was carried out to address issues related to the observed cracking of the titanium knife edges on the labyrinth seals of the high pressure fuel pump (HPFP) in the Space Shuttle main engine (SSME). Thermal shock experiments were carried out using a jet specimen with geometry similar to the knife edge geometry. These tests demonstrate that cracking of the titanium alloy is possible in a situation involving repeated thermal cycles over a wide temperature range, as might be realized during a rub in the liquid hydrogen fuel pump. High speed rub interaction tests were conducted using a representative knife edge and seal geometry over a broad range of interaction rates. Alternative materials were also experimentally evaluated. These tests provide information which can be used to design improved labyrinth seals for the HPFP of the SSME. In particular, plasma-sprayed aluminum-graphite was found to be significantly better than aluminum alloy seals used at present from the standpoint of rub performance. Ion nitriding of the titanium alloy knife edges was also found to improve rub performance compared with the untreated baseline knife edge material.

Development of a Laser Induced Fluorescence (LIF) system on the Plasma Material Interaction System (PLAMIS-II) device

NASA Astrophysics Data System (ADS)

Kang, I. J.; Lee, K. Y.; Lee, K. I.; Choi, Y.-S.; Cho, S. G.; Bae, M. K.; Lee, D.-H.; Hong, S. H.; Lho, T.; Chung, K.-S.

2015-12-01

A laser induced fluorescence (LIF) system has been developed for the plasma material interaction system (PLAMIS-II) device, which is equipped with a unique plasma gun composed of a LaB6 cathode and two anodes with electromagnets to generate a focused dense plasma. PLAMIS-II simulates the interactions of plasma with different materials and is to be used for the test of plasma facing components of fusion devices. The LIF system is composed of a seed laser with Littmann/Metcalf cavity and a master oscillator power amplifier to pump 3d4F7/2 metastable argon ion to 4p4D5/2 level at the wavelength of 668.61 nm, which has the following input parameters: laser power = 20 mW, line width < 100 kHz, and a mode-hop free tuning range > 70 GHz. For in-situ measurement of laser wavelength, the wavelength spectrum of an iodine cell was measured by a photo-transistor during LIF measurement. To measure argon ion temperature (Ti) and drift velocity (vd) in PLAMIS-II, the fluorescence light with the wavelength of 442.72 nm, emitted from 4p4D5/2 level to 4s4P3/2 level and passing through 1 nm band-width filter, was collected by the photomultiplier tube combined with a lock-in amplifier and a chopper with frequency of 3 kHz. Initial data of Ti and vd were analysed in terms of gas flow rate and applied power.

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

NASA Astrophysics Data System (ADS)

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.

Atmospheric-Pressure Plasma Interaction with Soft Materials as Fundamental Processes in Plasma Medicine.

PubMed

Takenaka, Kosuke; Miyazaki, Atsushi; Uchida, Giichiro; Setsuhara, Yuichi

2015-03-01

Molecular-structure variation of organic materials irradiated with atmospheric pressure He plasma jet have been investigated. Optical emission spectrum in the atmospheric-pressure He plasma jet has been measured. The spectrum shows considerable emissions of He lines, and the emission of O and N radicals attributed to air. Variation in molecular structure of Polyethylene terephthalate (PET) film surface irradiated with the atmospheric-pressure He plasma jet has been observed via X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). These results via XPS and FT-IR indicate that the PET surface irradiated with the atmospheric-pressure He plasma jet was oxidized by chemical and/or physical effect due to irradiation of active species.

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

NASA Astrophysics Data System (ADS)

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).

Report on final recommendations for IMPS engineering-science payload

NASA Technical Reports Server (NTRS)

Garrett, H. B.

1984-01-01

Six general categories of key scientific and engineering concerns for the interactions measurements payload for shuttle (IMPS) mission are addressed: (1) dielectric charging; (2) material property changes; (3) electromagnetic interference, plasma interactions, and plasma wake effects associated with high-voltage solar arrays and large space structures; (4) radio frequency distortion and nonlinearities due to the enhanced plasma in the shuttle ram/wake; (5) shuttle glow and contamination; and (6) plasma interactions with the space-based radar. Lesser concerns are the interactions associated with EVA; the radiation and SEU effects peculiar to the auroral/polar cap environments; and space debris. The measurements needed to address the concerns associated with the general categories are described and a list of generic investigations capable of making the required measurements, emphasizing the spectrum of measurements necessary to quantize the interactions in the auroral/polar environments are included. A suggested ground-test plan for the IMPS project, a description of proposed follow-on IMPS missions, and a detailed bibliography for each of the interactions discussed are included.

Plasma Jet Interaction with Thomson Scattering Probe Laser

NASA Astrophysics Data System (ADS)

Byvank, Tom; Banasek, Jacob; Potter, William; Kusse, Bruce

2016-10-01

Thomson scattering systems can diagnose plasma temperatures and velocities. When probing a plasma jet with the Thomson scattering laser, we observe a laser-plasma interaction that inputs energy into the plasma jet. The absorbed energy causes a bubble of low density ( 5*1017 cm-2) in the jet (unperturbed 1018 cm-2). A pulsed power machine (1 MA peak current, 100 ns rise time) with a radial foil (15 μm thick Al) configuration generates the plasma jet. We compare the effects of using 10 J and 1 J laser energies, for which the 10 J laser is a larger perturbation. We discuss how the interaction affects the Thomson scattering temperature and velocity measurements. Work supported by National Nuclear Security Administration (NNSA) Stewardship Sciences Academic Programs under Department of Energy (DOE) Cooperative Agreement DE-NA0001836 and National Science Foundation (NSF) Grant PHY-1102471.

The materials irradiation experiment for testing plasma facing materials at fusion relevant conditions

DOE PAGES

Garrison, L. M.; Zenobia, Samuel J.; Egle, Brian J.; ...

2016-08-01

The Materials Irradiation Experiment (MITE-E) was constructed at the University of Wisconsin-Madison Inertial Electrostatic Confinement Laboratory to test materials for potential use as plasma-facing materials (PFMs) in fusion reactors. PFMs in fusion reactors will be bombarded with x-rays, neutrons, and ions of hydrogen and helium. More needs to be understood about the interactions between the plasma and the materials to validate their use for fusion reactors. The MITE-E simulates some of the fusion reactor conditions by holding samples at temperatures up to 1000°C while irradiating them with helium or deuterium ions with energies from 10 to 150 keV. The ionmore » gun can irradiate the samples with ion currents of 20 μA–500 μA; the typical current used is 72 μA, which is an average flux of 9 × 10 14 ions/(cm 2 s). The ion gun uses electrostatic lenses to extract and shape the ion beam. A variable power (1-20 W), steady-state, Nd:YAG laser provides additional heating to maintain a constant sample temperature during irradiations. The ion beam current reaching the sample is directly measured and monitored in real-time during irradiations. The ion beam profile has been investigated using a copper sample sputtering experiment. In conclusion, the MITE-E has successfully been used to irradiate polycrystalline and single crystal tungsten samples with helium ions and will continue to be a source of important data for plasma interactions with materials.« less

The materials irradiation experiment for testing plasma facing materials at fusion relevant conditions.

PubMed

Garrison, L M; Zenobia, S J; Egle, B J; Kulcinski, G L; Santarius, J F

2016-08-01

The Materials Irradiation Experiment (MITE-E) was constructed at the University of Wisconsin-Madison Inertial Electrostatic Confinement Laboratory to test materials for potential use as plasma-facing materials (PFMs) in fusion reactors. PFMs in fusion reactors will be bombarded with x-rays, neutrons, and ions of hydrogen and helium. More needs to be understood about the interactions between the plasma and the materials to validate their use for fusion reactors. The MITE-E simulates some of the fusion reactor conditions by holding samples at temperatures up to 1000 °C while irradiating them with helium or deuterium ions with energies from 10 to 150 keV. The ion gun can irradiate the samples with ion currents of 20 μA-500 μA; the typical current used is 72 μA, which is an average flux of 9 × 10(14) ions/(cm(2) s). The ion gun uses electrostatic lenses to extract and shape the ion beam. A variable power (1-20 W), steady-state, Nd:YAG laser provides additional heating to maintain a constant sample temperature during irradiations. The ion beam current reaching the sample is directly measured and monitored in real-time during irradiations. The ion beam profile has been investigated using a copper sample sputtering experiment. The MITE-E has successfully been used to irradiate polycrystalline and single crystal tungsten samples with helium ions and will continue to be a source of important data for plasma interactions with materials.

The materials irradiation experiment for testing plasma facing materials at fusion relevant conditions

NASA Astrophysics Data System (ADS)

Garrison, L. M.; Zenobia, S. J.; Egle, B. J.; Kulcinski, G. L.; Santarius, J. F.

2016-08-01

The Materials Irradiation Experiment (MITE-E) was constructed at the University of Wisconsin-Madison Inertial Electrostatic Confinement Laboratory to test materials for potential use as plasma-facing materials (PFMs) in fusion reactors. PFMs in fusion reactors will be bombarded with x-rays, neutrons, and ions of hydrogen and helium. More needs to be understood about the interactions between the plasma and the materials to validate their use for fusion reactors. The MITE-E simulates some of the fusion reactor conditions by holding samples at temperatures up to 1000 °C while irradiating them with helium or deuterium ions with energies from 10 to 150 keV. The ion gun can irradiate the samples with ion currents of 20 μA-500 μA; the typical current used is 72 μA, which is an average flux of 9 × 1014 ions/(cm2 s). The ion gun uses electrostatic lenses to extract and shape the ion beam. A variable power (1-20 W), steady-state, Nd:YAG laser provides additional heating to maintain a constant sample temperature during irradiations. The ion beam current reaching the sample is directly measured and monitored in real-time during irradiations. The ion beam profile has been investigated using a copper sample sputtering experiment. The MITE-E has successfully been used to irradiate polycrystalline and single crystal tungsten samples with helium ions and will continue to be a source of important data for plasma interactions with materials.

Large-aperture Tunable Plasma Meta-material to Interact with Electromagnetic Waves

NASA Astrophysics Data System (ADS)

Corke, Thomas; Matlis, Eric

2016-11-01

The formation of spatially periodic arrangements of glow discharge plasma resulting from charge instabilities were investigated as a tuneable plasma meta-material. The plasma was formed between two 2-D parallel dielectric covered electrodes: one consisting of an Indium-Tin-Oxide coated glass sheet, and the other consisting of a glass-covered circular electrode. The dielectric covered electrodes were separated by a gap that formed a 2-D channel. The gap spacing was adjustable. The electrodes were powered by a variable amplitude AC generator. The parallel electrode arrangement was placed in a variable pressure vacuum chamber. Various combinations of gap spacing, pressure and voltage resulted in the formation of spatially periodic arrangements (lattice) of glow discharge plasma. The lattice spacing perfectly followed 2-D packing theory, and was fully adjustable through the three governing parameters. Lattice arrangements were designed to interact with electromagnetic (EM) waves in the frequency range between 10GHz-80GHz. Its feasibility was investigate through an EM wave simulation that we adapted to allow for plasma permittivity. The results showed a clear suppression of the EM wave amplitude through the plasma gratings. Supported by AFOSR.

TK Modeler version 1.0, a Microsoft® Excel®-based modeling software for the prediction of diurnal blood/plasma concentration for toxicokinetic use.

PubMed

McCoy, Alene T; Bartels, Michael J; Rick, David L; Saghir, Shakil A

2012-07-01

TK Modeler 1.0 is a Microsoft® Excel®-based pharmacokinetic (PK) modeling program created to aid in the design of toxicokinetic (TK) studies. TK Modeler 1.0 predicts the diurnal blood/plasma concentrations of a test material after single, multiple bolus or dietary dosing using known PK information. Fluctuations in blood/plasma concentrations based on test material kinetics are calculated using one- or two-compartment PK model equations and the principle of superposition. This information can be utilized for the determination of appropriate dosing regimens based on reaching a specific desired C(max), maintaining steady-state blood/plasma concentrations, or other exposure target. This program can also aid in the selection of sampling times for accurate calculation of AUC(24h) (diurnal area under the blood concentration time curve) using sparse-sampling methodologies (one, two or three samples). This paper describes the construction, use and validation of TK Modeler. TK Modeler accurately predicted blood/plasma concentrations of test materials and provided optimal sampling times for the calculation of AUC(24h) with improved accuracy using sparse-sampling methods. TK Modeler is therefore a validated, unique and simple modeling program that can aid in the design of toxicokinetic studies. Copyright © 2012 Elsevier Inc. All rights reserved.

Titania nanotube arrays as interfaces for blood-contacting implantable devices: a study evaluating the nanotopography-associated activation and expression of blood plasma components.

PubMed

Smith, Barbara S; Popat, Ketul C

2012-08-01

The constant exposure of implantable biomaterials such as titanium and titanium alloys to blood-introducesserious and ongoing concerns regarding poor blood-material interactions. To date, all blood-contacting materials have been shown to initiate immunological events in the form of inflammation, thrombosis, fibrosis and infection; potentially leading to complete implant failure. Material surfaces that provide biomimetic cues such as nanoscale architectures have been shown to elicit improved cellular interaction; and thus, may provide possible solutions for enhancing blood-compatibility. However, limited information exists about the thrombogenicityof nanoscalesurface architectures. In this study, we have evaluated the efficacy of titania nanotube arrays as interfaces for blood contacting devices by investigating the thrombogenic effects using whole blood plasma. Thus, platelet/leukocyte adhesion, activation and interaction, morphology, complement activation, contact activation, platelet release reaction, fibrinogen expression and material cytotoxicity were evaluated to determine the in vitro thrombogenicity. The results presented here indicate a decrease in thrombogenic effects of titania nanotube arrays as compared to biomedical grade titanium after 2 hours of contact with whole blood plasma. This work shows the improved blood-compatibility of titania nanotube arrays, identifying this specific nanoarchitecture as a potentially optimal interface for promoting the long-term success of blood contacting biomaterials.

Chondrules born in plasma? Simulation of gas-grain interaction using plasma arcs with applications to chondrule and cosmic spherule formation

NASA Astrophysics Data System (ADS)

Morlok, A.; Sutton, Y. C.; Braithwaite, N. St. J.; Grady, Monica M.

2012-12-01