Science.gov

Sample records for 1st plasma experiment

  1. Heavy Ion Fusion Science Virtual National Laboratory1st Quarter FY08 Milestone Report: Report Initial Work on Developing Plasma Modeling Capability in WARP for NDCX ExperimentsReport Initial work on developing Plasma Modeling Capability in WARP for NDCX Experiments

    SciTech Connect

    Friedman, A.; Cohen, R.H.; Grote, D.P.; Vay, J.-L.

    2007-12-10

    This milestone has been accomplished. The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) has developed and implemented an initial beam-in-plasma implicit modeling capability in Warp; has carried out tests validating the behavior of the models employed; has compared the results of electrostatic and electromagnetic models when applied to beam expansion in an NDCX-I relevant regime; has compared Warp and LSP results on a problem relevant to NDCX-I; has modeled wave excitation by a rigid beam propagating through plasma; and has implemented and begun testing a more advanced implicit method that correctly captures electron drift motion even when timesteps too large to resolve the electron gyro-period are employed. The HIFS-VNL is well on its way toward having a state-of-the-art source-to-target simulation capability that will enable more effective support of ongoing experiments in the NDCX series and allow more confident planning for future ones.

  2. First-Generation College Students' 1st-Year College Experiences: Challenges Attending a Private University

    ERIC Educational Resources Information Center

    Reid, Josephine

    2013-01-01

    First-generation college students (FGCS) face challenges when switching from high school to college and during their 1st-year in college. Additionally, FGCS may have difficulty understanding the steps required to prepare for and enroll in postsecondary education. The social capital theory examines support of social, academic, and cultural networks…

  3. Plasma properties from the multi-wavelength analysis of the November 1st 2003 CME/shock event

    PubMed Central

    Benna, Carlo; Mancuso, Salvatore; Giordano, Silvio; Gioannini, Lorenzo

    2012-01-01

    The analysis of the spectral properties and dynamic evolution of a CME/shock event observed on November 1st 2003 in white-light by the LASCO coronagraph and in the ultraviolet by the UVCS instrument operating aboard SOHO, has been performed to compute the properties of some important plasma parameters in the middle corona below about 2R⊙. Simultaneous observations obtained with the MLSO/Mk4 white-light coronagraph, providing both the early evolution of the CME expansion in the corona and the pre-shock electron density profile along the CME front, were also used to study this event. By combining the above information with the analysis of the metric type II radio emission detected by ground-based radio spectrographs, we finally derive estimates of the values of the local Alfvén speed and magnetic field strength in the solar corona. PMID:25685432

  4. PREFACE: 1st International Symposium on Electrical Arc and Thermal Plasmas in Africa (ISAPA)

    NASA Astrophysics Data System (ADS)

    Andre, Pascal; Koalaga, Zacharie

    2012-02-01

    Logos of the University of Ouagadougou, ISAPA and Universite Blaise Pascal Africa (especially Sub-Saharan Africa) is a continent where electrification is at a low level. However, the development of the electrical power sector is a prerequisite for the growth of other industrial activities, that is to say for the social and economic development of African countries. Consequently, a large number of electrification projects (rural electrification, interconnection of different country's grids) takes place in many countries. These projects need expertise and make Africa a continent of opportunity for companies in different domains for business and research: energy; energetic production, transmission, distribution and protection of electricity; the supply of cable; the construction, engineering and expertise in the field of solar and wind power. The first International Symposium on electrical Arc and thermal Plasma in Africa (ISAPA) was held for the first time in Ouagadougou, Burkina Faso to progress and develop the research of new physical developments, technical breakthroughs, and ideas in the fields of electrical production and electrical applications. The ISAPA aims to encourage the advancement of the science and applications of electrical power transformation in Africa by bringing together specialists from many areas in Africa and the rest of the world. Such considerations have led us to define a Scientific Committee including representatives from many countries. This first meeting was an innovative opportunity for researchers and engineers from academic and industrial sectors to exchange views and knowledge. Both fundamental aspects such as thermal plasma, electrical arc, diagnostics and applied aspects as circuit breakers, ICP analyses, photovoltaic energy conversion and alternative energies, as well as space applications were covered. The Laboratory of Material and Environment (LAME) from Ouagadougou University and the Laboratory of Electric Arc and Thermal

  5. [Prevention of the 1st bleeding of esophageal varices: review of the literature and clinical experience].

    PubMed

    Di Lecce, F; Contini, S

    1990-01-01

    The authors present a review of the literature on prophylactic sclerosis of esophageal varices in cirrhotics, taking as a starting point their personal experience. The natural history of varices and the criteria of their hemorrhagic risk are described; moreover are presented the results of the most important controlled studies of prophylactic surgery, sclerosis and beta-blocking drugs. In spite of the rather encouraging results after sclerosis at the long-term follow-up and the promising aspects of beta-blocking agents, it is not felt to recommend, according to the literature, a routine application of prophylactic sclerosis, a procedure which should be reserved to leading centers in controlled studies.

  6. Creating Research-Rich Learning Experiences and Quantitative Skills in a 1st Year Earth Systems Course

    NASA Astrophysics Data System (ADS)

    King, P. L.; Eggins, S.; Jones, S.

    2014-12-01

    We are creating a 1st year Earth Systems course at the Australian National University that is built around research-rich learning experiences and quantitative skills. The course has top students including ≤20% indigenous/foreign students; nonetheless, students' backgrounds in math and science vary considerably posing challenges for learning. We are addressing this issue and aiming to improve knowledge retention and deep learning by changing our teaching approach. In 2013-2014, we modified the weekly course structure to a 1hr lecture; a 2hr workshop with hands-on activities; a 2hr lab; an assessment piece covering all face-to-face activities; and a 1hr tutorial. Our new approach was aimed at: 1) building student confidence with data analysis and quantitative skills through increasingly difficult tasks in science, math, physics, chemistry, climate science and biology; 2) creating effective learning groups using name tags and a classroom with 8-person tiered tables; 3) requiring students to apply new knowledge to new situations in group activities, two 1-day field trips and assessment items; 4) using pre-lab and pre-workshop exercises to promote prior engagement with key concepts; 5) adding open-ended experiments to foster structured 'scientific play' or enquiry and creativity; and 6) aligning the assessment with the learning outcomes and ensuring that it contains authentic and challenging southern hemisphere problems. Students were asked to design their own ocean current experiment in the lab and we were astounded by their ingenuity: they simulated the ocean currents off Antarctica; varied water density to verify an equation; and examined the effect of wind and seafloor topography on currents. To evaluate changes in student learning, we conducted surveys in 2013 and 2014. In 2014, we found higher levels of student engagement with the course: >~80% attendance rates and >~70% satisfaction (20% neutral). The 2014 cohort felt that they were more competent in writing

  7. Experiments with nonneutral plasmas

    NASA Astrophysics Data System (ADS)

    O'Neil, T. M.

    2016-03-01

    Selected experiments with nonneutral plasmas are discussed. These include the laser cooling of a pure ion plasma to a crystalline state, a measurement of the Salpeter enhancement factor for fusion in a strongly correlated plasma and the measurement of thermally excited plasma waves. Also, discussed are experiments that demonstrate Landau damping, trapping and plasma wave echoes in the 2D ExB drift flow of a pure electron plasma, which is isomorphic to the 2D ideal flow (incompressible and inviscid flow) of a neutral fluid.

  8. FOREWORD: 13th International Workshop on Plasma-Facing Materials and Components for Fusion Applications/1st International Conference on Fusion Energy Materials Science 13th International Workshop on Plasma-Facing Materials and Components for Fusion Applications/1st International Conference on Fusion Energy Materials Science

    NASA Astrophysics Data System (ADS)

    Jacob, Wolfgang; Linsmeier, Christian; Rubel, Marek

    2011-12-01

    The 13th International Workshop on Plasma-Facing Materials and Components (PFMC-13) jointly organized with the 1st International Conference on Fusion Energy Materials Science (FEMaS-1) was held in Rosenheim (Germany) on 9-13 May 2011. PFMC-13 is a successor of the International Workshop on Carbon Materials for Fusion Applications series. Between 1985 and 2003 ten 'Carbon Workshops' were organized in Jülich, Stockholm and Hohenkammer. Then it was time for a change and redefinition of the scope of the symposium to reflect the new requirements of ITER and the ongoing evolution in the field. Under the new name (PFMC-11), the workshop was first organized in 2006 in Greifswald, Germany and PFMC-12 took place in Jülich in 2009. Initially starting in 1985 with about 40 participants as a 1.5 day workshop, the event has continuously grown to about 220 participants at PFMC-12. Due to the joint organization with FEMaS-1, PFMC-13 set a new record with more than 280 participants. The European project Fusion Energy Materials Science, FEMaS, coordinated by the Max-Planck-Institut für Plasmaphysik (IPP), organizes and stimulates cooperative research activities which involve large-scale research facilities as well as other top-level materials characterization laboratories. Five different fields are addressed: benchmarking experiments for radiation damage modelling, the application of micro-mechanical characterization methods, synchrotron and neutron radiation-based techniques and advanced nanoscopic analysis based on transmission electron microscopy. All these fields need to be exploited further by the fusion materials community for timely materials solutions for a DEMO reactor. In order to integrate these materials research fields, FEMaS acted as a co-organizer for the 2011 workshop and successfully introduced a number of participants from research labs and universities into the PFMC community. Plasma-facing materials experience particularly hostile conditions as they are

  9. Quantitative Proteomic (iTRAQ) Analysis of 1st Trimester Maternal Plasma Samples in Pregnancies at Risk for Preeclampsia

    PubMed Central

    Kolla, Varaprasad; Jenö, Paul; Moes, Suzette; Lapaire, Olav; Hoesli, Irene; Hahn, Sinuhe

    2012-01-01

    A current major obstacle is that no reliable screening markers exist to detect pregnancies at risk for preeclampsia. Quantitative proteomic analysis employing isobaric labelling (iTRAQ) has been suggested to be suitable for the detection of potential plasma biomarkers, a feature we recently verified in analysis of pregnancies with Down syndrome foetuses. We have now examined whether this approach could yield biomarkers to screen pregnancies at risk for preeclampsia. In our study, we used maternal plasma samples obtained at 12 weeks of gestation, six from women who subsequently developed preeclampsia and six with uncomplicated deliveries. In our analysis, we observed elevations in 10 proteins out of 64 proteins in the preeclampsia study group when compared to the healthy control group. These proteins included clusterin, fibrinogen, fibronectin, and angiotensinogen, increased levels of which are known to be associated with preeclampsia. An elevation in the immune-modulatory molecule, galectin 3 binding protein, was also noted. Our pilot study, therefore, indicates that quantitative proteomic iTRAQ analysis could be a useful tool for the detection of new preeclampsia screening markers. PMID:22570525

  10. Madison Plasma Dynamo Experiment

    NASA Astrophysics Data System (ADS)

    Kostadinova, Evdokiya; Forest, C.; Cooper, C.; Coquerel, M.

    2014-01-01

    The Madison Plasma Dynamo Experiment (MPDX) is investigating the self-generation of magnetic fields and related processes in a large, weakly magnetized, fast flowing, and hot (conducting) plasma. The dynamo re-creates conditions highly similar to many astrophysical plasmas. Stars and other planets have dynamos, and so do galaxies and clusters of galaxies, which makes it extremely crucial for researchers in the field to carry out experiments in this previously uninvestigated plasma regime, which will help for the development of a comprehensive theory of how magnetic fields are generated in planets, the Sun and other stars. MPDX is a laboratory astrophysical experiment where 200,000-degree Fahrenheit plasma is confined within a three-meter diameter spherical aluminum vacuum chamber with the help of multiple tracks of cusp magnets covering the inside shell. The dynamo utilizes six robotic insertion sweep probes that are programmed to find any point inside the sphere by given radial and angular coordinates. This innovative mechanical system allows us to take measurements of the state variables in key points in the plasma flow and to better investigate its cosmic-like plasma behavior. The probes are able to autonomously calculate coordinate transformations, move in a two dimensional plane, and return information about their relative position. This makes them an extremely useful, highly accurate, and easily controlled tool for plasma analysis.

  11. Plasma stabilization experiment

    NASA Astrophysics Data System (ADS)

    Sziklas, E. A.; Fader, W. J.; Jong, R. A.; Stufflebeam, J. H.

    1980-07-01

    The plasma stabilization experiment is an effort to enhance stability in a mirror-confined plasma by trapping cold ions with rf fields applied near the mirror throats. Nagoya Type 3 antennas, coupled to a 60 kW rf power supply are mounted in the throats of the UTRC baseball magnet. An external washer gun provides a source of plasma for both streaming and confined plasma tests. Results show a strong stoppering effect on streaming plasmas and a marginal effect on confined plasmas. Theoretical calculations provide an explanation for the experimental observations. The field generates a ponderomotive force acting on the electrons. The resultant improvement in electron confinement changes the ambipolar potential and inhibits the flow of ions through the mirror throat. Criteria are derived for the validity of this trapping concept. The requisite field strengths are significantly lower than those required to trap ions directly. Scaling laws are developed for application of cold ion trapping to large mirror devices containing dense plasmas. The use of slow-wave antenna structures operated at frequencies above the lower hybrid frequency is recommended for these applications.

  12. CRRES plasma wave experiment

    NASA Technical Reports Server (NTRS)

    Anderson, Roger R.; Gurnett, Donald A.; Odem, Daniel L.

    1992-01-01

    The CRRES plasma wave experiment is designed to provide information on the plasma wave environment and the total plasma density in the Earth's radiation belts and throughout the CRRES orbit. This information is valuable both for studying the naturally occurring wave-particle interactions affecting the plasma and particle environment in the plasmasphere and magnetosphere as well as for studying the chemical releases. The electric field sensors for this instrument consist of two long electric dipole antennas (about 100 m tip-to-tip), and the magnetic field sensor is a search coil magnetometer mounted at the end of a 6-m boom. The instrument has a 14-channel spectrum analyzer covering the frequency range from 5.6 Hz to 10 kHz, and a 128-step sweep frequency receiver covering the frequency range from 100 Hz to 400 kHz.

  13. Construction and 1st Experiment of the 500-meter and 1000-meter DC Superconducting Power Cable in Ishikari

    NASA Astrophysics Data System (ADS)

    Yamaguchi, S.; Ivanov, Y.; Watanabe, H.; Chikumoto, N.; Koshiduka, H.; Hayashi, K.; Sawamura, T.

    Ishikari project constructs two lines. The length of the Line 1 is 500 m, and connects the photovoltaic cell to the internet-data center. The other line is 1 km length, and it is a test facility and called Line 2. The structures of the cable systems are not same to test their performance. The construction was started from 2014 in the field, the Line 1 was completed in May 2015, and it was cooled down and do the current experiment, and warmed up. The Line 2 is almost complete in October 2015. It will be tested in November and December, 2015. In order to reduce the stress of the cable induced by the thermal expansion and contraction, we adopted the way of the helical deformation of the cable. The force of the cable is reduced to 1/3 of an usual cable test. Because the cryogenic pipes are welded in the field and we cannot use the baking of the vacuum chamber of the cryogenic pipe, a new vacuum pumping method was proposed and tested for the cryogenic pipe. Since the straight pipes are used to compose the cryogenic pipe, the pressure drop of the circulation would be 1/100 of the corrugated pipe in the present condition, and it is suitable for longer cable system. The heat leak of the cryogenic pipe is ∼1.4W/m including the cable pipe's and the return pipe's. The heat leak of the current lead is ∼30W/kA in the test bench. Finally the current of 6kA/3 sec and the current of 5kA/15 min were achieved in Line 1. The reduction of heat leak will be a major subject of the longer cable system. The cost of the construction will be almost twice higher than that of the copper and aluminum over-head line with the iron tower in the present Japan. The cost construction of the over-head line is an average value, and depends on the newspaper.

  14. FOREWORD: 13th International Workshop on Plasma-Facing Materials and Components for Fusion Applications/1st International Conference on Fusion Energy Materials Science 13th International Workshop on Plasma-Facing Materials and Components for Fusion Applications/1st International Conference on Fusion Energy Materials Science

    NASA Astrophysics Data System (ADS)

    Jacob, Wolfgang; Linsmeier, Christian; Rubel, Marek

    2011-12-01

    The 13th International Workshop on Plasma-Facing Materials and Components (PFMC-13) jointly organized with the 1st International Conference on Fusion Energy Materials Science (FEMaS-1) was held in Rosenheim (Germany) on 9-13 May 2011. PFMC-13 is a successor of the International Workshop on Carbon Materials for Fusion Applications series. Between 1985 and 2003 ten 'Carbon Workshops' were organized in Jülich, Stockholm and Hohenkammer. Then it was time for a change and redefinition of the scope of the symposium to reflect the new requirements of ITER and the ongoing evolution in the field. Under the new name (PFMC-11), the workshop was first organized in 2006 in Greifswald, Germany and PFMC-12 took place in Jülich in 2009. Initially starting in 1985 with about 40 participants as a 1.5 day workshop, the event has continuously grown to about 220 participants at PFMC-12. Due to the joint organization with FEMaS-1, PFMC-13 set a new record with more than 280 participants. The European project Fusion Energy Materials Science, FEMaS, coordinated by the Max-Planck-Institut für Plasmaphysik (IPP), organizes and stimulates cooperative research activities which involve large-scale research facilities as well as other top-level materials characterization laboratories. Five different fields are addressed: benchmarking experiments for radiation damage modelling, the application of micro-mechanical characterization methods, synchrotron and neutron radiation-based techniques and advanced nanoscopic analysis based on transmission electron microscopy. All these fields need to be exploited further by the fusion materials community for timely materials solutions for a DEMO reactor. In order to integrate these materials research fields, FEMaS acted as a co-organizer for the 2011 workshop and successfully introduced a number of participants from research labs and universities into the PFMC community. Plasma-facing materials experience particularly hostile conditions as they are

  15. "Hard Science" for Gifted 1st Graders

    ERIC Educational Resources Information Center

    DeGennaro, April

    2006-01-01

    "Hard Science" is designed to teach 1st grade gifted students accurate and high level science concepts. It is based upon their experience of the world and attempts to build a foundation for continued love and enjoyment of science. "Hard Science" provides field experiences and opportunities for hands-on discovery working beside experts in the field…

  16. The Impact of Gender-Fair versus Gender-Stereotyped Basal Readers on 1st-Grade Children's Gender Stereotypes: A Natural Experiment

    ERIC Educational Resources Information Center

    Karniol, Rachel; Gal-Disegni, Michal

    2009-01-01

    Israeli 1st-grade children in two different schools in the same neighborhood who were using either a gender-stereotyped or a gender-fair basal reader were asked to judge for a series of female-stereotyped, male-stereotyped, and gender-neutral activities whether they were characteristic of females, of males, or of both. Children using the…

  17. The Black Experience: Social, Cultural and Economic Considerations. Proceedings of a Workshop on the Black Experience. (1st, Chapel Hill, North Carolina, March 14, 1980).

    ERIC Educational Resources Information Center

    Johnson, Audreye E., Ed.

    This publication consists of the proceedings of a workshop on the social, cultural, and economic experiences of Blacks. The workshops' goals were to intensify the interest of social workers in the Black experience; to examine the values which have an impact on services to Black people; to increase the knowledge of social workers about Blacks; and…

  18. Plasma Wakefield Experiments at FACET

    SciTech Connect

    Hogan, M.J.; England, R.J.; Frederico, J.; Hast, C.; Li, S.Z.; Litos, M.; Walz, D.; An, W.; Clayton, C.E.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.; Tochitsky, S.; Muggli, P.; Pinkerton, S.; Shi, Y.; /Southern California U.

    2011-08-19

    FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration beginning in summer 2011. The nominal FACET parameters are 23GeV, 3nC electron bunches compressed to {approx}20{micro}m long and focused to {approx}10{micro}m wide. The intense fields of the FACET bunches will be used to field ionize neutral lithium or cesium vapor produced in a heat pipe oven. Previous experiments at the SLAC FFTB facility demonstrated 50GeV/m gradients in an 85cm field ionized lithium plasma where the interaction distance was limited by head erosion. Simulations indicate the lower ionization potential of cesium will decrease the rate of head erosion and increase single stage performance. The initial experimental program will compare the performance of lithium and cesium plasma sources with single and double bunches. Later experiments will investigate improved performance with a pre-ionized cesium plasma. The status of the experiments and expected performance are reviewed. The FACET Facility is being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The facility will begin commissioning in summer 2011 and conduct an experimental program over the coming five years to study electron and positron beam driven plasma acceleration with strong wake loading in the non-linear regime. The FACET experiments aim to demonstrate high-gradient acceleration of electron and positron beams with high efficiency and negligible emittance growth.

  19. Pharmacokinetics of human activated protein C. 1st communication: plasma concentration and excretion of a lyophilized purified human activated protein C after intravenous administration in the mouse and the rabbit.

    PubMed

    Ishii, S; Mochizuki, T; Nagao, T; Sugiki, S; Kudo, S; Harakawa, N; Taniguchi, K; Igarashi, Y; Kondo, S; Kiyoki, M

    1995-05-01

    Pharmacokinetic studies of human activated protein C (CAS 42617-41-4, APC) were investigated in mice and rabbits with 125I-labeled compound. Plasma levels of APC were determined by three different assays: total radioactivity, APC antigenicity determined by sandwich enzyme-linked immunosorbent assay (ELISA), and the amidolytic activity which was performed by immunologically captured APC. APC concentration obtained from these assays were shown to be correlated well at early times post-dose. After intravenous administration, total radioactivity in the plasma declined tri-exponentially, but antigenicity and amidolytic activity in the plasma declined biexponentially. Plasma AUC increased proportionally with the dose, and the total body clearance and t1/2 did not change significantly. In addition, no significant difference was observed between the pharmacokinetics in male and female mice. In rabbit study, the profiles of times vs APC concentration in the plasma was similar to those in mice after single bolus injection. The plasma concentrations of APC during and after infusion in rabbits were also determined. APC concentration increased during infusion and reached almost steady state at the end of infusion. The profiles of the APC concentration in benzamidine citrate plasma corresponded to the simulated curves which were characterized by the parameters obtained from the single bolus experiment. Plasma disposition profiles of the protein were studied with high performance gel chromatography method. The radioactivity in the unchanged APC was observed at 15 min after administration. At 1 h, most of the radioactivity was observed in larger molecule fraction than the intact APC. These results corresponded to the decrease of amidolytic activity in the plasma.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7612068

  20. Magnetized Plasma Experiments Using Thermionic- Thermoelectronic Plasma Emitter

    NASA Astrophysics Data System (ADS)

    Kawamori, Eiichirou; Cheng, C. Z.; Fujikawa, Nobuko; Lee, Jyun-Yi; Peng, Albert

    2008-11-01

    We are developing a magnetic mirror device, which is the first magnetized plasma device in Taiwan, to explore basic plasma sciences relevant to fusion, space and astrophysical plasmas. Our research subjects include electromagnetically induced transparency (EIT), Alfven wave physics, and plasma turbulence. A large diameter (> 200 mm) plasma emitter1, which utilizes thermionic- thermoelectronic emission from a mixture of LaB6 (Lanthanum-hexaboride) and beta-eucryptite (lithium type aluminosylicate) powders, is employed as a plasma source because of its production ability of fully ionized plasma and controllability of plasma emission rate. The plasma emitter has been installed recently and investigation of its characteristics will be started. The employment of beta-eucryptite in plasma emitter is the first experimental test because such investigation of beta-eucryptite has previously been used only for Li+-ion source2. Our plan for magnetized plasma experiments and results of the plasma emitter investigation will be presented. 1. K. Saeki, S. Iizuka, N. Sato, and Y. Hatta, Appl. Phys. Lett., 37, 1980, pp. 37-38. 2. M. Ueda, R. R. Silva, R. M. Oliveira, H. Iguchi, J. Fujita and K. Kadota, J. Phys. D: Appl. Phys. 30 1997, pp. 2711--2716.

  1. Dense Plasma Injection Experiment at MCX

    NASA Astrophysics Data System (ADS)

    Uzun-Kaymak, I.; Messer, S.; Bomgardner, R.; Case, A.; Clary, R.; Ellis, R.; Elton, R.; Hassam, A.; Teodorescu, C.; Witherspoon, D.; Young, W.

    2009-09-01

    We present preliminary results of the High Density Plasma Injection Experiment at the Maryland Centrifugal Experiment (MCX). HyperV Technologies Corp. has designed, built, and installed a prototype coaxial gun to drive rotation in MCX. This gun has been designed to avoid the blow-by instability via a combination of electrode shaping and a tailored plasma armature. An array of diagnostics indicates the gun is capable of plasma jets with a mass of 160 μg at 70 km/s with an average plasma density above 1015 cm-3. Preliminary measurements are underway at MCX to understand the penetration of the plasma jet through the MCX magnetic field and the momentum transfer from the jet to the MCX plasma. Data will be presented for a wide range of MCX field parameters, and the prospects for future injection experiments will be evaluated.

  2. E-157: A Plasma Wakefield Acceleration Experiment

    SciTech Connect

    Muggli, Patrick

    2000-10-20

    The E-157 plasma wakefield experiment addresses issues relevant to a meter long plasma accelerator module. In particular, a 1.4 m long plasma source has been developed for the experiment. The transverse dynamics of the beam in the plasma is studied: multiple betatron oscillations of the beam envelope, flipping of the beam tail, stability against the hose instability, emission of synchrotron radiation by the beam in the plasma. The bending of the 28.5 GeV beam at the plasma/vapor interface is observed for the first time. The longitudinal dynamics of the beam, i.e. the energy loss and gain by the electrons in the wake, is strongly affected by the oscillation of the beam tail instability.

  3. Meter scale plasma source for plasma wakefield experiments

    SciTech Connect

    Vafaei-Najafabadi, N.; Shaw, J. L.; Marsh, K. A.; Joshi, C.; Hogan, M. J.

    2012-12-21

    High accelerating gradients generated by a high density electron beam moving through plasma has been used to double the energy of the SLAC electron beam [1]. During that experiment, the electron current density was high enough to generate its own plasma without significant head erosion. In the newly commissioned FACET facility at SLAC, the peak current will be lower and without pre-ionization, head erosion will be a significant challenge for the planned experiments. In this work we report on our design of a meter scale plasma source for these experiments to effectively avoid the problem of head erosion. The plasma source is based on a homogeneous metal vapor gas column that is generated in a heat pipe oven [2]. A lithium oven over 30 cm long at densities over 10{sup 17} cm{sup -3} has been constructed and tested at UCLA. The plasma is then generated by coupling a 10 TW short pulse Ti:Sapphire laser into the gas column using an axicon lens setup. The Bessel profile of the axicon setup creates a region of high intensity that can stretch over the full length of the gas column with approximately constant diameter. In this region of high intensity, the alkali metal vapor is ionized through multi-photon ionization process. In this manner, a fully ionized meter scale plasma of uniform density can be formed. Methods for controlling the plasma diameter and length will also be discussed.

  4. Plasma flow switch experiment on Procyon

    SciTech Connect

    Benage, J.F. Jr.; Bowers, R.; Peterson, D.

    1995-09-01

    This report presents the results obtained from a series of plasma flow switch experiments done on the Procyon explosive pulse power generator. These experiments involved switching into a fixed inductance dummy load and also into a dynamic implosion load. The results indicated that the switch did fairly well at switching current into the load, but the results for the implosion are more ambiguous. The results are compared to calculations and the implications for future plasma flow switch work are discussed.

  5. Plasma flow switch experiment on Procyon

    NASA Astrophysics Data System (ADS)

    Benage, J. F., Jr.; Bowers, R.; Peterson, D.

    This report presents the results obtained from a series of plasma flow switch experiments done on the Procyon explosive pulse power generator. These experiments involved switching into a fixed inductance dummy load and also into a dynamic implosion load. The results indicated that the switch did fairly well at switching current into the load, but the results for the implosion are more ambiguous. The results are compared to calculations and the implications for future plasma flow switch work are discussed.

  6. Solar Array Module Plasma Interaction Experiment (SAMPIE)

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.

    1992-01-01

    The objective of the Solar Array Module Plasma Interaction Experiment (SAMPIE) is to investigate, by means of a shuttle-based flight experiment and relevant ground-based testing, the arcing and current collection behavior of materials and geometries likely to be exposed to the LEO plasma on high-voltage space power systems, in order to minimize adverse environmental interactions. An overview of the SAMPIE program is presented in outline and graphical form.

  7. Mini-Magnetospheric Plasma Propulsion Experiment (MMPX)

    NASA Astrophysics Data System (ADS)

    Ziemba, Tim; Slough, John; Winglee, Robert

    1999-11-01

    The MMPX is a new laboratory device that is designed to study plasma dynamics and confinement in a magnetic dipole with field strengths ranging from 0.01 to 0.2 T. The magnetic dipole is constructed of two short solenoidal Helmholtz coils with a 0.3 m diameter. Plasma is injected onto the field lines by a Helicon source located on the inner, high field side of the dipole field. Plasma densities of 1-2× 10^19m-3 are expected with electron temperatures of 4 eV or greater. As plasma flows out along the dipole field, the background neutral pressure is kept low to maintain the plasma in a collisionless, ``frozen-in'' state. As the local field decreases, the plasma pressure eventually exceeds the field pressure. At this point the magnetic flux will be pulled dynamically outward with the plasma. Observation of this flux expansion is the major goal of the experiment. In space the continued expansion of the dipole flux will be inhibited only by the solar wind pressure. The configuration would thus act as a large scale ( ~ 30 km) magneto-plasma barrier to the solar wind, and would allow for spacecraft propulsion with megawatt thrust power from a kilowatt source.

  8. Magnetic Flux Compression Experiments Using Plasma Armatures

    NASA Technical Reports Server (NTRS)

    Turner, M. W.; Hawk, C. W.; Litchford, R. J.

    2003-01-01

    Magnetic flux compression reaction chambers offer considerable promise for controlling the plasma flow associated with various micronuclear/chemical pulse propulsion and power schemes, primarily because they avoid thermalization with wall structures and permit multicycle operation modes. The major physical effects of concern are the diffusion of magnetic flux into the rapidly expanding plasma cloud and the development of Rayleigh-Taylor instabilities at the plasma surface, both of which can severely degrade reactor efficiency and lead to plasma-wall impact. A physical parameter of critical importance to these underlying magnetohydrodynamic (MHD) processes is the magnetic Reynolds number (R(sub m), the value of which depends upon the product of plasma electrical conductivity and velocity. Efficient flux compression requires R(sub m) less than 1, and a thorough understanding of MHD phenomena at high magnetic Reynolds numbers is essential to the reliable design and operation of practical reactors. As a means of improving this understanding, a simplified laboratory experiment has been constructed in which the plasma jet ejected from an ablative pulse plasma gun is used to investigate plasma armature interaction with magnetic fields. As a prelude to intensive study, exploratory experiments were carried out to quantify the magnetic Reynolds number characteristics of the plasma jet source. Jet velocity was deduced from time-of-flight measurements using optical probes, and electrical conductivity was measured using an inductive probing technique. Using air at 27-inHg vacuum, measured velocities approached 4.5 km/s and measured conductivities were in the range of 30 to 40 kS/m.

  9. Results from Plasma Wakefield Experiments at FACET

    SciTech Connect

    Li, S.Z.; Clarke, C.I.; England, R.J.; Frederico, J.; Gessner, S.J.; Hogan, M.J.; Jobe, R.K.; Litos, M.D.; Walz, D.R.; Muggli, P.; An, W.; Clayton, C.E.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.; Tochitsky, S.; Adli, E.; /U. Oslo

    2011-12-13

    We report initial results of the Plasma Wakefield Acceleration (PWFA) Experiments performed at FACET - Facility for Advanced aCcelertor Experimental Tests at SLAC National Accelerator Laboratory. At FACET a 23 GeV electron beam with 1.8 x 10{sup 10} electrons is compressed to 20 {mu}m longitudinally and focused down to 10 {mu}m x 10 {mu}m transverse spot size for user driven experiments. Construction of the FACET facility completed in May 2011 with a first run of user assisted commissioning throughout the summer. The first PWFA experiments will use single electron bunches combined with a high density lithium plasma to produce accelerating gradients > 10 GeV/m benchmarking the FACET beam and the newly installed experimental hardware. Future plans for further study of plasma wakefield acceleration will be reviewed. The experimental hardware and operation of the plasma heat-pipe oven have been successfully commissioned. Plasma wakefield acceleration was not observed because the electron bunch density was insufficient to ionize the lithium vapor. The remaining commissioning time in summer 2011 will be dedicated to delivering the FACET design parameters for the experimental programs which will begin in early 2012. PWFA experiments require the shorter bunches and smaller transverse sizes to create the plasma and drive large amplitude wakefields. Low emittance and high energy will minimize head erosion which was found to be a limiting factor in acceleration distance and energy gain. We will run the PWFA experiments with the design single bunch conditions in early 2012. Future PWFA experiments at FACET are discussed in [5][6] and include drive and witness bunch production for high energy beam manipulation, ramped bunch to optimize tranformer ratio, field-ionized cesium plasma, preionized plasmas, positron acceleration, etc.. We will install a notch collimator for two-bunch operation as well as new beam diagnostics such as the X-band TCAV [7] to resolve the two bunches

  10. Diagnostics for the plasma liner experiment.

    PubMed

    Lynn, A G; Merritt, E; Gilmore, M; Hsu, S C; Witherspoon, F D; Cassibry, J T

    2010-10-01

    The goal of the Plasma Liner Experiment (PLX) is to explore and demonstrate the feasibility of forming imploding spherical "plasma liners" via merging high Mach number plasma jets to reach peak liner pressures of ∼0.1 Mbar using ∼1.5 MJ of initial stored energy. Such a system would provide HED plasmas for a variety of fundamental HEDLP, laboratory astrophysics, and materials science studies, as well as a platform for experimental validation of rad-hydro and rad-MHD simulations. It could also prove attractive as a potential standoff driver for magnetoinertial fusion. Predicted parameters from jet formation to liner stagnation cover a large range of plasma density and temperature, varying from n(i)∼10(16) cm(-3), T(e)≈T(i)∼1 eV at the plasma gun mouth to n(i)>10(19) cm(-3), T(e)≈T(i)∼0.5 keV at stagnation. This presents a challenging problem for the plasma diagnostics suite which will be discussed.

  11. Diagnostics for the Plasma Liner Experiment

    SciTech Connect

    Lynn, A. G.; Merritt, E.; Gilmore, M.; Hsu, S. C.; Witherspoon, F. D.; Cassibry, J. T.

    2010-10-15

    The goal of the Plasma Liner Experiment (PLX) is to explore and demonstrate the feasibility of forming imploding spherical ''plasma liners'' via merging high Mach number plasma jets to reach peak liner pressures of {approx}0.1 Mbar using {approx}1.5 MJ of initial stored energy. Such a system would provide HED plasmas for a variety of fundamental HEDLP, laboratory astrophysics, and materials science studies, as well as a platform for experimental validation of rad-hydro and rad-MHD simulations. It could also prove attractive as a potential standoff driver for magnetoinertial fusion. Predicted parameters from jet formation to liner stagnation cover a large range of plasma density and temperature, varying from n{sub i}{approx}10{sup 16} cm{sup -3}, T{sub e}{approx_equal}T{sub i}{approx}1 eV at the plasma gun mouth to n{sub i}>10{sup 19} cm{sup -3}, T{sub e}{approx_equal}T{sub i}{approx}0.5 keV at stagnation. This presents a challenging problem for the plasma diagnostics suite which will be discussed.

  12. Plasma Guns for the Plasma Liner Experiment (PLX)

    NASA Astrophysics Data System (ADS)

    Witherspoon, F. D.; Bomgardner, R.; Case, A.; Messer, S. J.; Brockington, S.; Wu, L.; Elton, R.; Hsu, S. C.; Cassibry, J. T.; Gilmore, M. A.

    2009-11-01

    A spherical array of minirailgun plasma accelerators is planned for the Plasma Liner Experiment (PLX) to be located at LANL. The plasma liner would be formed via merging of 30 dense, high Mach number plasma jets (n˜10^16-17 cm-3, M˜10--35, v˜50--70 km/s, rjet˜5 cm) in a spherically convergent geometry. Small parallel-plate railguns are being developed for this purpose due to their reduced system complexity and cost, with each gun planned to operate at ˜300 kA peak current, and launching up to ˜8000 μg of high-Z plasma using a ˜50 kJ pfn. We describe experimental development of the minirailguns and their current and projected performance. Fast operating repetitive gas valves have recently been added to allow injection of high density gases including helium, argon, and (eventually) xenon. We will present the latest test results with the high-Z gases, and discuss future plans for augmenting the rails, optimizing the nozzle configuration, preionizing the injected gas, and configuring the pulse forming networks with the capacitors available to the program.

  13. Overview of the Plasma Liner Experiment (PLX)

    NASA Astrophysics Data System (ADS)

    Hsu, S. C.; Witherspoon, F. D.; Cassibry, J. T.; Gilmore, M. A.; the PLX Team

    2011-10-01

    The Plasma Liner Experiment (PLX) is a multi-institutional collaboration that is exploring and demonstrating the formation of imploding spherical plasma liners to reach peak pressures exceeding 0.1 Mbar upon stagnation. The liners will be formed via the merging of 30 dense high Mach number plasma jets (n ~1017 cm-3, M ~ 10 -35, v ~ 50 km/s, rjet ~ 2 . 5 cm) in a spherically convergent geometry. We are aiming for two follow-on applications if this work is successful: (1) assembling repetitive, macroscopic (cm and μs scale) plasmas suitable for fundamental HEDLP scientific studies and (2) a standoff driver for magneto-inertial fusion. This is a staged project where scientific issues will be studied first at modest stored energies (~ 300 kJ) before attempting to reach HED- relevant pressures (requiring ~ 1 . 5 MJ). This poster provides an overview of the project's status/plans and emphasizes the progress made in the past year: completion of phase one facility and diagnostic construction, progress in numerical simulations, and initial experiments on single jet propagation and two jet merging. Finally, we describe cosmically-relevant collisionless shock experiments based on the head-on collision of two lower density but higher velocity plasma jets. Supported by DOE Fusion Energy Sciences and LANL LDRD.

  14. SPDE: Solar Plasma Diagnostic Experiment

    NASA Technical Reports Server (NTRS)

    Bruner, Marilyn E.

    1995-01-01

    The physics of the Solar corona is studied through the use of high resolution soft x-ray spectroscopy and high resolution ultraviolet imagery. The investigation includes the development and application of a flight instrument, first flown in May, 1992 on NASA sounding rocket 36.048. A second flight, NASA founding rocket 36.123, took place on 25 April 1994. Both flights were successful in recording new observations relevant to the investigation. The effort in this contract covers completion of the modifications to the existing rocket payload, its reflight, and the preliminary day reduction and analysis. Experience gained from flight 36.048 led us to plan several payload design modifications. These were made to improve the sensitivity balance between the UV and EUV spectrographs, to improve the scattered light rejection in the spectrographs, to protect the visible light rejection filter for the Normal Incidence X-ray Imager instrument (NIXI), and to prepare one new multilayer mirror coating to the NIXI. We also investigated the addition of a brassboard CCD camera to the payload to test it as a possible replacement for the Eastman type 101-07 film used by the SPDE instruments. This camera was included in the experimeter's data package for the Project Initiation Conference for the flight of NASA Mission 36.123, held in January, 1994, but for programmatic reasons was deleted from the final payload configuration. The payload was shipped to the White Sands Missile Range on schedule in early April. The launch and successful recovery took place on 25 April, in coordination with the Yohkoh satellite and a supporting ground-based observing campaign.

  15. Magnetic Nozzle and Plasma Detachment Experiment

    NASA Technical Reports Server (NTRS)

    Chavers, Gregory; Dobson, Chris; Jones, Jonathan; Martin, Adam; Bengtson, Roger D.; Briezman, Boris; Arefiev, Alexey; Cassibry, Jason; Shuttpelz, Branwen; Deline, Christopher

    2006-01-01

    High power plasma propulsion can move large payloads for orbit transfer (such as the ISS), lunar missions, and beyond with large savings in fuel consumption owing to the high specific impulse. At high power, lifetime of the thruster becomes an issue. Electrodeless devices with magnetically guided plasma offer the advantage of long life since magnetic fields confine the plasma radially and keep it from impacting the material surfaces. For decades, concerns have been raised about the plasma remaining attached to the magnetic field and returning to the vehicle along the closed magnetic field lines. Recent analysis suggests that this may not be an issue of the magnetic field is properly shaped in the nozzle region and the plasma has sufficient energy density to stretch the magnetic field downstream. An experiment was performed to test the theory regarding the Magneto-hydrodynamic (MHD) detachment scenario. Data from this experiment will be presented. The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) being developed by the Ad Astra Rocket Company uses a magnetic nozzle as described above. The VASIMR is also a leading candidate for exploiting an electric propulsion test platform being considered for the ISS.

  16. Lock No. 1 St. Lucie Canal. Sector gates, internal struts ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Lock No. 1- St. Lucie Canal. Sector gates, internal struts- nose beams. - St. Lucie Canal, St. Lucie Lock No. 1, St. Lucie, Cross State Canal, Okeechobee Intracoastal Waterway, Stuart, Martin County, FL

  17. Laboratory plasma physics experiments using merging supersonic plasma jets

    DOE PAGES

    Hsu, S. C.; Moser, A. L.; Merritt, E. C.; Adams, C. S.; Dunn, J. P.; Brockington, S.; Case, A.; Gilmore, M.; Lynn, A. G.; Messer, S. J.; et al

    2015-04-01

    We describe a laboratory plasma physics experiment at Los Alamos National Laboratory that uses two merging supersonic plasma jets formed and launched by pulsed-power-driven railguns. The jets can be formed using any atomic species or mixture available in a compressed-gas bottle and have the following nominal initial parameters at the railgun nozzle exit: ne ≈ ni ~ 10¹⁶ cm⁻³, Te ≈ Ti ≈ 1.4 eV, Vjet ≈ 30–100 km/s, mean chargemore » $$\\bar{Z}$$ ≈ 1, sonic Mach number Ms ≡ Vjet/Cs > 10, jet diameter = 5 cm, and jet length ≈ 20 cm. Experiments to date have focused on the study of merging-jet dynamics and the shocks that form as a result of the interaction, in both collisional and collisionless regimes with respect to the inter-jet classical ion mean free path, and with and without an applied magnetic field. However, many other studies are also possible, as discussed in this paper.« less

  18. Laboratory plasma physics experiments using merging supersonic plasma jets

    SciTech Connect

    Hsu, S. C.; Moser, A. L.; Merritt, E. C.; Adams, C. S.; Dunn, J. P.; Brockington, S.; Case, A.; Gilmore, M.; Lynn, A. G.; Messer, S. J.; Witherspoon, F. D.

    2015-04-01

    We describe a laboratory plasma physics experiment at Los Alamos National Laboratory that uses two merging supersonic plasma jets formed and launched by pulsed-power-driven railguns. The jets can be formed using any atomic species or mixture available in a compressed-gas bottle and have the following nominal initial parameters at the railgun nozzle exit: ne ≈ ni ~ 10¹⁶ cm⁻³, Te ≈ Ti ≈ 1.4 eV, Vjet ≈ 30–100 km/s, mean charge $\\bar{Z}$ ≈ 1, sonic Mach number Ms ≡ Vjet/Cs > 10, jet diameter = 5 cm, and jet length ≈ 20 cm. Experiments to date have focused on the study of merging-jet dynamics and the shocks that form as a result of the interaction, in both collisional and collisionless regimes with respect to the inter-jet classical ion mean free path, and with and without an applied magnetic field. However, many other studies are also possible, as discussed in this paper.

  19. Magnetized laboratory plasma jets: experiment and simulation.

    PubMed

    Schrafel, Peter; Bell, Kate; Greenly, John; Seyler, Charles; Kusse, Bruce

    2015-01-01

    Experiments involving radial foils on a 1 MA, 100 ns current driver can be used to study the ablation of thin foils and liners, produce extreme conditions relevant to laboratory astrophysics, and aid in computational code validation. This research focuses on the initial ablation phase of a 20 μm Al foil (8111 alloy), in a radial configuration, driven by Cornell University's COBRA pulsed power generator. In these experiments ablated surface plasma (ASP) on the top side of the foil and a strongly collimated axial plasma jet are observed developing midway through the current rise. With experimental and computational results this work gives a detailed description of the role of the ASP in the formation of the plasma jet with and without an applied axial magnetic field. This ∼1 T field is applied by a Helmholtz-coil pair driven by a slow, 150 μs current pulse and penetrates the load hardware before arrival of the COBRA pulse. Several effects of the applied magnetic field are observed: (1) without the field extreme-ultraviolet emission from the ASP shows considerable azimuthal asymmetry while with the field the ASP develops azimuthal motion that reduces this asymmetry, (2) this azimuthal motion slows the development of the jet when the field is applied, and (3) with the magnetic field the jet becomes less collimated and has a density minimum (hollowing) on the axis. PERSEUS, an XMHD code, has qualitatively and quantitatively reproduced all these experimental observations. The differences between this XMHD and an MHD code without a Hall current and inertial effects are discussed. In addition the PERSEUS results describe effects we were not able to resolve experimentally and suggest a line of future experiments with better diagnostics. PMID:25679726

  20. Magnetized laboratory plasma jets: Experiment and simulation

    NASA Astrophysics Data System (ADS)

    Schrafel, Peter; Bell, Kate; Greenly, John; Seyler, Charles; Kusse, Bruce

    2015-01-01

    Experiments involving radial foils on a 1 M A , 100 n s current driver can be used to study the ablation of thin foils and liners, produce extreme conditions relevant to laboratory astrophysics, and aid in computational code validation. This research focuses on the initial ablation phase of a 20 μ m Al foil (8111 alloy), in a radial configuration, driven by Cornell University's COBRA pulsed power generator. In these experiments ablated surface plasma (ASP) on the top side of the foil and a strongly collimated axial plasma jet are observed developing midway through the current rise. With experimental and computational results this work gives a detailed description of the role of the ASP in the formation of the plasma jet with and without an applied axial magnetic field. This ˜1 T field is applied by a Helmholtz-coil pair driven by a slow, 150 μ s current pulse and penetrates the load hardware before arrival of the COBRA pulse. Several effects of the applied magnetic field are observed: (1) without the field extreme-ultraviolet emission from the ASP shows considerable azimuthal asymmetry while with the field the ASP develops azimuthal motion that reduces this asymmetry, (2) this azimuthal motion slows the development of the jet when the field is applied, and (3) with the magnetic field the jet becomes less collimated and has a density minimum (hollowing) on the axis. PERSEUS, an XMHD code, has qualitatively and quantitatively reproduced all these experimental observations. The differences between this XMHD and an MHD code without a Hall current and inertial effects are discussed. In addition the PERSEUS results describe effects we were not able to resolve experimentally and suggest a line of future experiments with better diagnostics.

  1. Microwave Plasma Window Theory and Experiments

    NASA Astrophysics Data System (ADS)

    McKelvey, Andrew; Zheng, Peng; Franzi, Matthew; Lau, Y. Y.; Gilgenbach, Ronald; Plasma, Pulsed Power,; Microwave Laboratory Team

    2011-10-01

    The microwave plasma window is an experiment designed to promote RF breakdown in a controlled vacuum-gas environment using a DC bias. Experimental data has shown that this DC bias will significantly reduce the RF power required to yield breakdown, a feature also shown in recent simulation. The cross-polarized conducting array is biased at (100's V) DC on the surface of a Lucite vacuum window. Microwave power is supplied to the window's surface by a single 1-kW magnetron operating at 2.45 GHz CW. The goal of this project is to establish controllable characteristics relating vacuum pressure, DC bias, RF power required for surface breakdown, as well as RF transmission after the formation of plasma. Experimental data will be compared with multipactor susceptibility curves generated using a Monte Carlo simulation which incorporates an applied DC bias and finite pressures of air and argon. Research supported by an AFOSR grant on the Basic Physics of Distributed Plasma Discharge, AFRL, L-3 Communications, and Northrop Grumman.

  2. Plasma shape experiments for an optimized tokamak

    NASA Astrophysics Data System (ADS)

    Hyatt, A. W.; Osborne, T. H.; Lazarus, E. A.

    1994-07-01

    In this paper we present results from recent experiments at DIII-D which measured the plasma stability and confinement performance product, beta(tau)(sub E), in one previously studied and three new plasma shapes. One important goal of these experiments was to identify performance vs. shape trends which would identify a shape compatible with both high performance and the planned effort to decrease the power flux to the divertor floor using a closed 'slot' divertor geometry. The closed divertor hardware must be designed for a reduced set of plasma shapes, so care must be taken to choose the shape that optimizes beta(tau)(sub E) and divertor performance. The four shapes studied form a matrix of moderate and high elongations (kappa congruent to 1.8 and 2.1) and low and high triangularities (delta congruent to 0.3 and 0.9). All configurations were double-null diverted (DND), held fixed during a shot, with neutral beam heating. The shapes span a range of X-point locations compatible with the envisioned closed divertor. We find that from shape to shape, a shot's transient normalized performance, beta(sub N)H, where beta(sub N) is equivalent to beta/(I(sup p)/aB(sub T)) and H is equivalent to tau(sub E)/tau(sub E)(sup ITER-89P), increases strongly with triangularity, but depends only weakly on elongation. However, the normalized performance during quasi stationary ELMing H-mode, to which these discharges eventually relax, is insensitive to both triangularity and elongation. The moderate elongation, high triangularity DND shape is shown to be near optimum for future studies on DIII-D.

  3. Magnetized plasma jets in experiment and simulation

    NASA Astrophysics Data System (ADS)

    Schrafel, Peter; Greenly, John; Gourdain, Pierre; Seyler, Charles; Blesener, Kate; Kusse, Bruce

    2013-10-01

    This research focuses on the initial ablation phase of a thing (20 micron) Al foil driven on the 1 MA-in-100 ns COBRA through a 5 mm diameter cathode in a radial configuration. In these experiments, ablated surface plasma (ASP) on the top of the foil and a strongly collimated axial plasma jet can be observed developing midway through current-rise. Our goal is to establish the relationship between the ASP and the jet. These jets are of interest for their potential relevance to astrophysical phenomena. An independently pulsed 200 μF capacitor bank with a Helmholtz coil pair allows for the imposition of a slow (150 μs) and strong (~1 T) axial magnetic field on the experiment. Application of this field eliminates significant azimuthal asymmetry in extreme ultraviolet emission of the ASP. This asymmetry is likely a current filamentation instability. Laser-backlit shadowgraphy and interferometry confirm that the jet-hollowing is correlated with the application of the axial magnetic field. Visible spectroscopic measurements show a doppler shift consistent with an azimuthal velocity in the ASP caused by the applied B-field. Computational simulations with the XMHD code PERSEUS qualitatively agree with the experimental results.

  4. A Physics Exploratory Experiment on Plasma Liner Formation

    NASA Technical Reports Server (NTRS)

    Thio, Y. C. Francis; Knapp, Charles E.; Kirkpatrick, Ronald C.; Siemon, Richard E.; Turchi, Peter

    2002-01-01

    Momentum flux for imploding a target plasma in magnetized target fusion (MTF) may be delivered by an array of plasma guns launching plasma jets that would merge to form an imploding plasma shell (liner). In this paper, we examine what would be a worthwhile experiment to do in order to explore the dynamics of merging plasma jets to form a plasma liner as a first step in establishing an experimental database for plasma-jets driven magnetized target fusion (PJETS-MTF). Using past experience in fusion energy research as a model, we envisage a four-phase program to advance the art of PJETS-MTF to fusion breakeven Q is approximately 1). The experiment (PLX (Plasma Liner Physics Exploratory Experiment)) described in this paper serves as Phase I of this four-phase program. The logic underlying the selection of the experimental parameters is presented. The experiment consists of using twelve plasma guns arranged in a circle, launching plasma jets towards the center of a vacuum chamber. The velocity of the plasma jets chosen is 200 km/s, and each jet is to carry a mass of 0.2 mg - 0.4 mg. A candidate plasma accelerator for launching these jets consists of a coaxial plasma gun of the Marshall type.

  5. New diagnostic facilities for Caltech plasma experiments

    NASA Astrophysics Data System (ADS)

    Zhai, Xiang; Bellan, Paul

    2011-10-01

    An optically coupled high voltage probe (HV probe) and a visible and near infrared (VNIR) detector are being developed for Caltech solar coronal loop and astrophysical jet experiments. The HV probe uses a capacitive voltage divider coupled a fast LED to convert the electrical signal into an optical signal, which is then conveyed to a receiver via an optical fiber. A solar cell array powered by ambient laboratory lighting charges a capacitor that when triggered acts as a short-duration power supply for an onboard amplifier in the HV probe. The fast VNIR detector combined with specific atomic line filters measures the spectra with 10ns time resolution. Measurements show that before detachment, the gross VNIR emission power of the solar coronal plasma loop is a function of the axial electric current. H α and H β line emission power is found to be 102 ~103 greater than predicted by assuming local thermodynamic equilibrium. This indicates that the plasma is not in an ionization-recombination equilibrium state and can have a larger population of neutrals than predicted for an equilibrium state. NSF, DOE, AFOSR

  6. Plasma gun pellet acceleration modeling and experiment

    SciTech Connect

    Kincaid, R.W.; Bourham, M.A.; Gilligan, J.G.

    1996-12-31

    Modifications to the electrothermal plasma gun SIRENS have been completed to allow for acceleration experiments using plastic pellets. Modifications have been implemented to the 1-D, time dependent code ODIN to include pellet friction, momentum, and kinetic energy with options of variable barrel length. The code results in the new version, POSEIDON, compare favorably with experimental data and with code results from ODIN. Predicted values show an increased pellet velocity along the barrel length, achieving 2 km/s exit velocity. Measured velocity, at three locations along the barrel length, showed good correlation with predicted values. The code has also been used to investigate the effectiveness of longer pulse length on pellet velocity using simulated ramp up and down currents with flat top, and triangular current pulses with early and late peaking. 16 refs., 5 figs.

  7. Electron density and plasma dynamics of a colliding plasma experiment

    NASA Astrophysics Data System (ADS)

    Wiechula, J.; Schönlein, A.; Iberler, M.; Hock, C.; Manegold, T.; Bohlender, B.; Jacoby, J.

    2016-07-01

    We present experimental results of two head-on colliding plasma sheaths accelerated by pulsed-power-driven coaxial plasma accelerators. The measurements have been performed in a small vacuum chamber with a neutral-gas prefill of ArH2 at gas pressures between 17 Pa and 400 Pa and load voltages between 4 kV and 9 kV. As the plasma sheaths collide, the electron density is significantly increased. The electron density reaches maximum values of ≈8 ṡ 1015 cm-3 for a single accelerated plasma and a maximum value of ≈2.6 ṡ 1016 cm-3 for the plasma collision. Overall a raise of the plasma density by a factor of 1.3 to 3.8 has been achieved. A scaling behavior has been derived from the values of the electron density which shows a disproportionately high increase of the electron density of the collisional case for higher applied voltages in comparison to a single accelerated plasma. Sequences of the plasma collision have been taken, using a fast framing camera to study the plasma dynamics. These sequences indicate a maximum collision velocity of 34 km/s.

  8. First results of the plasma wakefield acceleration experiment at PITZ

    NASA Astrophysics Data System (ADS)

    Lishilin, O.; Gross, M.; Brinkmann, R.; Engel, J.; Grüner, F.; Koss, G.; Krasilnikov, M.; Martinez de la Ossa, A.; Mehrling, T.; Osterhoff, J.; Pathak, G.; Philipp, S.; Renier, Y.; Richter, D.; Schroeder, C.; Schütze, R.; Stephan, F.

    2016-09-01

    The self-modulation instability of long particle beams was proposed as a new mechanism to produce driver beams for proton driven plasma wakefield acceleration (PWFA). The PWFA experiment at the Photo Injector Test facility at DESY, Zeuthen site (PITZ) was launched to experimentally demonstrate and study the self-modulation of long electron beams in plasma. Key aspects for the experiment are the very flexible photocathode laser system, a plasma cell and well-developed beam diagnostics. In this contribution we report about the plasma cell design, preparatory experiments and the results of the first PWFA experiment at PITZ.

  9. SAFE II: Large systems space plasma evaluation experiment

    NASA Astrophysics Data System (ADS)

    Carruth, M. R., Jr.; Young, L. E.; Purvis, C. K.; Stevens, N. J.

    1983-05-01

    A shuttle flight experiment, the purpose of which is to obtain space data on the interaction of a high voltage solar array with the ambient space plasma is addressed. This flight experiment is a reflight of the solar array flight experiment, SAFE, except that three active solar array panels, electron release devices and plasma diagnostics are added. This experiment, SAFE 2, evaluates power loss due to parasitic current collected by the solar array, arcing on the solar array and perturbations to the plasma which may increase power loss and disturb plasma and charged particle science acquisition.

  10. Dusty Plasma Experiments Using an Electrodynamic Balance

    NASA Technical Reports Server (NTRS)

    Spann, J. F.; Abbas, M. M.; Suess, S. T.; Venturini, C. C.; Comfort, R. H.

    2000-01-01

    Knowledge of the formation, distribution, physical, chemical and optical characteristics of interstellar, interplanetary, and planetary dust grains provide valuable information about many issues dealing with the origin and formation of the solar system bodies, interplanetary and interstellar environments as well as various industrial processes. Understanding the microphysics of individual grains and their interaction with the surrounding environment is key to properly model various conditions and interpret existing data. The theory and models of individual dust grains are well developed for environments that vary from dense planetary atmospheres to dusty plasmas to diffuse environments such is interplanetary space. However, experimental investigations of individual dust grains in equilibrium are less common, perhaps due to the difficult of these experiments. Laboratory measurements of dust grains have primarily measured ensemble properties or transient properties of single grains. A technique developed in the 1950's for ion spectroscopy, known as a quadrupole trap or 'Paul Trap', has recently been used to investigate single micron-sized dust grains. This scaled ion trap called an electrodynamic balance has been used for atmospheric aerosol research. A description of this technique is provided. Recent results from experiments to investigate the equilibrium potential of dust grains exposed to far ultraviolet light or to -,in electron or ion beam are presented. This laboratory technique ]ends itself to many applications that relate to planetary atmospheres, heliospheric environments, pre-stellar and pre-planetary conditions, and industrial settings. Several planned experimental approaches are presented. Potential experiments to investigate the interaction of multiple dust grains using an electrodynamic balance are proposed.

  11. Oscillating plasma bubbles. II. Pulsed experiments

    SciTech Connect

    Stenzel, R. L.; Urrutia, J. M.

    2012-08-15

    Time-dependent phenomena have been investigated in plasma bubbles which are created by inserting spherical grids into an ambient plasma and letting electrons and ions form a plasma of different parameters than the ambient one. There are no plasma sources inside the bubble. The grid bias controls the particle flux. There are sheaths on both sides of the grid, each of which passes particle flows in both directions. The inner sheath or plasma potential develops self consistently to establish charge neutrality and divergence free charge and mass flows. When the electron supply is restricted, the inner sheath exhibits oscillations near the ion plasma frequency. When all electrons are excluded, a virtual anode forms on the inside sheath, reflects all ions such that the bubble is empty. By pulsing the ambient plasma, the lifetime of the bubble plasma has been measured. In an afterglow, plasma electrons are trapped inside the bubble and the bubble decays as slow as the ambient plasma. Pulsing the grid voltage yields the time scale for filling and emptying the bubble. Probes have been shown to modify the plasma potential. Using pulsed probes, transient ringing on the time scale of ion transit times through the bubble has been observed. The start of sheath oscillations has been investigated. The instability mechanism has been qualitatively explained. The dependence of the oscillation frequency on electrons in the sheath has been clarified.

  12. 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.

  13. The Burning Plasma Experiment conventional facilities

    SciTech Connect

    Commander, J.C.

    1991-01-01

    The Burning Program Plasma Experiment (BPX) is phased to start construction of conventional facilities in July 1994, in conjunction with the conclusion of the Tokamak Fusion Test Reactor (TFTR) project. This paper deals with the conceptual design of the BPX Conventional Facilities, for which Functional and Operational Requirements (F ORs) were developed. Existing TFTR buildings and utilities will be adapted and used to satisfy the BPX Project F ORs to the maximum extent possible. However, new conventional facilities will be required to support the BPX project. These facilities include: The BPX building; Site improvements and utilities; the Field Coil Power Conversion (FCPC) building; the TFTR modifications; the Motor Generation (MG) building; Liquid Nitrogen (LN{sub 2}) building; and the associated Instrumentation and Control (I C) systems. The BPX building will provide for safe and efficient shielding, housing, operation, handling, maintenance and decontamination of the BPX and its support systems. Site improvements and utilities will feature a utility tunnel which will provide a space for utility services--including pulse power duct banks and liquid nitrogen coolant lines. The FCPC building will house eight additional power supplied for the Toroidal Field (TF) coils. The MG building will house the two MG sets larger than the existing TFTR MG sets. This paper also addresses the conventional facility cost estimating methodology and the rationale for the construction schedule developed. 6 figs., 1 tab.

  14. The Burning Plasma Experiment conventional facilities

    SciTech Connect

    Commander, J.C.

    1991-12-01

    The Burning Program Plasma Experiment (BPX) is phased to start construction of conventional facilities in July 1994, in conjunction with the conclusion of the Tokamak Fusion Test Reactor (TFTR) project. This paper deals with the conceptual design of the BPX Conventional Facilities, for which Functional and Operational Requirements (F&ORs) were developed. Existing TFTR buildings and utilities will be adapted and used to satisfy the BPX Project F&ORs to the maximum extent possible. However, new conventional facilities will be required to support the BPX project. These facilities include: The BPX building; Site improvements and utilities; the Field Coil Power Conversion (FCPC) building; the TFTR modifications; the Motor Generation (MG) building; Liquid Nitrogen (LN{sub 2}) building; and the associated Instrumentation and Control (I&C) systems. The BPX building will provide for safe and efficient shielding, housing, operation, handling, maintenance and decontamination of the BPX and its support systems. Site improvements and utilities will feature a utility tunnel which will provide a space for utility services--including pulse power duct banks and liquid nitrogen coolant lines. The FCPC building will house eight additional power supplied for the Toroidal Field (TF) coils. The MG building will house the two MG sets larger than the existing TFTR MG sets. This paper also addresses the conventional facility cost estimating methodology and the rationale for the construction schedule developed. 6 figs., 1 tab.

  15. An Experiment to Tame the Plasma Material Interface

    SciTech Connect

    Goldston, R J; Menard, J E; Allain, J P; Brooks, J N; Canik, J M; Doerner, R; Fu, G; Gates, D A; Gentile, C A; Harris, J H; Hassanein, A; Gorelenkov, N N; Kaita, R; Kaye, S M; Kotschenreuther, M; Kramer, G J; Kugel, H W; Maingi, R; Mahajan, S M; Majeski, R; Neumeyer, C L; Nygren, R E; Ono, M; Owen, L W; Ramakrishnan, S; Rognlien, T D; Ruzic, D N; Ryutov, D D; Sabbagh, S A; Skinner, C H; Soukhanovskii, V A; Stevenson, T N; Ulrickson, M A; Valanju, P M; Woolley, R D

    2009-01-08

    The plasma material interface in Demo will be more challenging than that in ITER, due to requirements for approximately four times higher heat flux from the plasma and approximately five times higher average duty factor. The scientific and technological solutions employed in ITER may not extrapolate to Demo. The key questions to be resolved for Demo and the resulting key requirements for an experiment to 'tame the plasma material interface' are analyzed. A possible design point for such an experiment is outlined.

  16. Progress of plasma wakefield self-modulation experiments at FACET

    NASA Astrophysics Data System (ADS)

    Adli, E.; Berglyd Olsen, V. K.; Lindstrøm, C. A.; Muggli, P.; Reimann, O.; Vieira, J. M.; Amorim, L. D.; Clarke, C. I.; Gessner, S. J.; Green, S. Z.; Hogan, M. J.; Litos, M. D.; O`Shea, B. D.; Yakimenko, V.; Clayton, C.; Marsh, K. A.; Mori, W. B.; Joshi, C.; Vafaei-Najafabadi, N.; Williams, O.

    2016-09-01

    Simulations and theory predict that long electron and positron beams may under favorable conditions self-modulate in plasmas. We report on the progress of experiments studying the self-modulation instability in plasma wakefield experiments at FACET. The experimental results obtained so far, while not being fully conclusive, appear to be consistent with the presence of the self-modulation instability.

  17. Analysis and experiments of a whistler-wave plasma thruster

    SciTech Connect

    Hooper, E.B.; Ferguson, S.W.; Makowski, M.A.; Stallard, B.W.; Power, J.L.

    1993-08-06

    A plasma thruster operating at high specific impulse ({ge} 3500 s) has been proposed to be based on electron-cyclotron resonance heating of whistler waves propagating on a plasma column on a magnetic hill. Calculations using a particle-in-cell code demonstrate that the distortion of the electron velocity distribution by the heating significantly reduces the flow of plasma up the field, greatly improving efficiency and reducing material interactions relative to a thermal plasma. These and other calculations are presented together with initial experiments on the plasma generated in the proposed device. The experiments are conducted in a magnetic field (3.3 {times} 10{sup {minus}2} T at resonance) and a magnetic mirror ratio of 5. Microwaves (0.915 GHz, <20 kW) are coupled to the plasma with a helical antenna. Vacuum field measurements are in good agreement with prediction. The desired plasma spatial distribution has not yet been achieved.

  18. Experiments and Theory of Dusty Plasmas

    SciTech Connect

    Shukla, P. K.

    2011-11-29

    The purpose of this paper is to present the most important theoretical and experimental discoveries that have been made in the area of dusty plasma physics. We describe the physics and observations of the well celebrated dust acoustic wave (DAW) and the dust ion-acoustic wave (DIAW) in dusty plasmas with weakly coupled dust grains, as well as the dust Coulomb crystal and dust lattice oscillations (DLOs) in dusty plasmas with strongly coupled dust grains. In dusty plasmas, the dust charge fluctuation is a dynamical variable, which provides a novel collisionless damping of the DA and DIA waves. The latter and the DLOs are excited by external sources, which are here discussed. Besides the Debye-Hueckel short-range repulsive force between like charged dust grains, there are novel attractive forces (e.g. due to dipole-dipole dust particle interactions, overlapping Debye spheres, ion focusing and ion wakefields, dipole magnetic moments etc.), which provide unique possibilities for attracting charged dust particles of similar polarity. The dust particle attraction is responsible for the formation of dust Coulomb crystals in laboratory dusty plasmas, as well as for the formation of planets and large astrophysical bodies in the Milky Way galaxy and in interstellar media. Furthermore, the nonlinear DAW, DIAW, and DLOs also appear in the form of solitary and shock waves, the physics and observations of which are briefly discussed. Finally, we discuss possible applications of dust-in-plasmas and dusty plasmas in laboratory and space.

  19. Pre-plasma formation in experiments using petawatt lasers.

    PubMed

    Wagner, Florian; Bedacht, Stefan; Ortner, Alex; Roth, Markus; Tauschwitz, Anna; Zielbauer, Bernhard; Bagnoud, Vincent

    2014-12-01

    We used time-resolved shadowgraphy to characterize the pre-plasma formation in solid-target interaction experiments with micrometer-scale accuracy. We performed quantitative measurements of the plasma density for amplified spontaneous emission (ASE) levels ranging from 2 · 10(-7) to 10(-10) backed with 2-dimensional hydrodynamic simulations. We find that ASE levels above 10(-9) are able to create a significant pre-plasma plume that features a plasma canal driving a self-focusing of the laser beam. For ASE levels of 10(-10), no ASE pre-plasma could be detected.

  20. Plasma-materials interactions during rf experiments in tokamaks

    SciTech Connect

    Cohen, S.A.; Bernabei, S.; Budny, R.; Chu, T.K.; Colestock, P.; Hinnov, E.; Hooke, W.; Hosea, J.; Hwang, D.; Jobes, F.

    1984-09-01

    Plasma-materials interactions studied in recent ICRF heating and lower hybrid current drive experiments are reviewed. The microscopic processes responsible for impurity generation are discussed. In ICRF experiments, improvements in machine operation and in antenna and feedthrough design have allowed efficient plasma heating at RF powers up to 3 MW. No significant loss of energy from the plasma core due to impurity radiation occurs. Lower hybrid current drive results in the generation and maintenance of hundreds of kiloamperes of plasma current carried by suprathermal electrons. The loss of these electrons and their role in impurity generation are assessed. Methods to avoid this problem are evaluated.

  1. Experiments on the Propagation of Plasma Filaments

    SciTech Connect

    Katz, Noam; Egedal, Jan; Fox, Will; Le, Ari; Porkolab, Miklos

    2008-07-04

    We investigate experimentally the motion and structure of isolated plasma filaments propagating through neutral gas. Plasma filaments, or 'blobs,' arise from turbulent fluctuations in a range of plasmas. Our experimental geometry is toroidally symmetric, and the blobs expand to a larger major radius under the influence of a vertical electric field. The electric field, which is caused by {nabla}B and curvature drifts in a 1/R magnetic field, is limited by collisional damping on the neutral gas. The blob's electrostatic potential structure and the resulting ExB flow field give rise to a vortex pair and a mushroom shape, which are consistent with nonlinear plasma simulations. We observe experimentally this characteristic mushroom shape for the first time. We also find that the blob propagation velocity is inversely proportional to the neutral density and decreases with time as the blob cools.

  2. Using the Tritium Plasma Experiment to evaluate ITER PFC safety. [Plasma-Facing Components

    SciTech Connect

    Longhurst, G.R.; Anderl, R.A. ); Bartlit, J.R. ); Causey, R.A. ); Haines, J.R. )

    1993-01-01

    The Tritium Plasma Experiment was assembled at Sandia National Laboratories, Livermore to investigate interactions between dense plasmas at low energies and plasma-facing component materials. This apparatus has the unique capability of replicating plasma conditions in a tokamak divertor with particle flux densities of 2 [times] 10[sup 19] ions/cm[sup 2] [center dot] s and a plasma temperature of about 15 eV using a plasma that includes tritium. With the closure of the Tritium Research Laboratory at Livermore, the experiment was moved to the Tritium Systems Test Assembly facility at Los Alamos National Laboratory. An experimental program has been initiated there using the Tritium Plasma Experiment to examine safety issues related to tritium in plasma-facing components, particularly the ITER divertor. Those issues include tritium retention and release characteristics, tritium permeation rates and transient times to coolant streams, surface modification and erosion by the plasma, the effects of thermal loads and cycling, and particulate production. A considerable lack of data exists in these areas for many of the materials, especially beryllium, being considered for use in ITER. Not only will basic material behavior with respect to safety issues in the divertor environment be examined, but innovative techniques for optimizing performance with respect to tritium safety by material modification and process control will be investigated. Supplementary experiments will be carried out at the Idaho National Engineering Laboratory and Sandia National Laboratory to expand and clarify results obtained on the Tritium Plasma Experiment.

  3. EMSL Quarterly Highlights Report: 1st Quarter, FY08

    SciTech Connect

    Showalter, Mary Ann

    2008-01-28

    The EMSL Quarterly Highlights Report covers the science, staff and user recognition, and publication activities that occurred during the 1st quarter (October 2007 - December 2007) of Fiscal Year 2008.

  4. EMSL Quarterly Highlights Report: 1st Quarter, Fiscal Year 2009

    SciTech Connect

    Showalter, Mary Ann; Kathmann, Loel E.; Manke, Kristin L.

    2009-02-02

    The EMSL Quarterly Highlights Report covers the science, staff and user recognition, and publication activities that occurred during the 1st quarter (October 2008 - December 2008) of Fiscal Year 2009.

  5. ISS Update: 1st Annual ISS R&D Conference

    NASA Video Gallery

    NASA Public Affairs Officer Kelly Humphries talks by phone on Wednesday with Julie Robinson, ISS Program Scientist, about the 1st Annual International Space Station Research and Development Confere...

  6. 1st Baby Born with DNA from 3 Parents

    MedlinePlus

    ... news/fullstory_161176.html 1st Baby Born With DNA From 3 Parents Technique designed to help couples ... be born using a controversial technique that combines DNA from three people -- two women and a man. ...

  7. FDA OKs 1st Drug to Treat Duchenne Muscular Dystrophy

    MedlinePlus

    ... html FDA OKs 1st Drug to Treat Duchenne Muscular Dystrophy Exondys 51 seems to fill unmet need for ... the first drug for a rare form of muscular dystrophy. Exondys 51 (eteplirsen) was granted accelerated approval to ...

  8. Hollow cathode-based plasma contactor experiments for electrodynamic tether

    NASA Astrophysics Data System (ADS)

    Patterson, Michael J.

    1987-01-01

    The role plasma contactors play in effective electrodynamic tether operation is discussed. Hollow cathodes and hollow cathode-based plasma sources have been identified as leading candidates for the electrodynamic tether plasma contactor. Present experimental efforts to evaluate the suitability of these devices as plasma contactors are reviewed. This research includes the definition of preliminary plasma contactor designs, and the characterization of their operation as electron collectors from a simulated space plasma. The discovery of an 'ignited mode' regime of high contactor efficiency and low impedance is discussed, as well as is the application of recent models of the plasma coupling process to contactor operation. Results indicate that ampere-level electron currents can be exchanged between hollow cathode-based plasma contactors and a dilute plasma in this regime. A discussion of design considerations for plasma contactors is given which includes expressions defining the total mass flow rate and power requirements of plasma contactors operating in both the cathodic and anodic regimes, and correlation of this to the tether current. Finally, future ground and spaceflight experiments are proposed to resolve critical issues of plasma contactor operation.

  9. Stopping Power in Dense Plasmas: Models, Simulations and Experiments

    NASA Astrophysics Data System (ADS)

    Grabowski, Paul; Fichtl, Chris; Graziani, Frank; Hazi, Andrew; Murillo, Michael; Sheperd, Ronnie; Surh, Mike; Cimarron Collaboration

    2011-10-01

    Our goal is to conclusively determine the minimal model for stopping power in dense plasmas via a three-pronged theoretical, simulation, and experimental program. Stopping power in dense plasma is important for ion beam heating of targets (e.g., fast ignition) and alpha particle energy deposition in inertial confinement fusion targets. We wish to minimize our uncertainties in the stopping power by comparing a wide range of theoretical approaches to both detailed molecular dynamics (MD) simulations and experiments. The largest uncertainties occur for slow-to-moderate velocity projectiles, dense plasmas, and highly charged projectiles. We have performed MD simulations of a classical, one component plasma to reveal where there are weaknesses in our kinetic theories of stopping power, over a wide range of plasma conditions. We have also performed stopping experiments of protons in heated warm dense carbon for validation of such models, including MD calculations, of realistic plasmas for which bound contributions are important.

  10. Preliminary results of noncircular plasma experiments in Doublet III

    SciTech Connect

    Ohkawa, T.

    1980-02-01

    Preliminary results of noncircular plasma experiments in Doublet III are reported. Shaping and discharge characteristics in doublet plasmas with high-Z limiters are described. Electron energy confinement and maximum plasma density are in agreement with standard circular tokamak empirical scaling laws. Chromium and molybdenum appear to be the dominant high-Z contaminants while carbon appears to dominate low-Z contaminants. High-Z impurity radiation does not appear to dominate the central power balance.

  11. The INAF/IAPS Plasma Chamber for ionospheric simulation experiment

    NASA Astrophysics Data System (ADS)

    Diego, Piero

    2016-04-01

    The plasma chamber is particularly suitable to perform studies for the following applications: - plasma compatibility and functional tests on payloads envisioned to operate in the ionosphere (e.g. sensors onboard satellites, exposed to the external plasma environment); - calibration/testing of plasma diagnostic sensors; - characterization and compatibility tests on components for space applications (e.g. optical elements, harness, satellite paints, photo-voltaic cells, etc.); - experiments on satellite charging in a space plasma environment; - tests on active experiments which use ion, electron or plasma sources (ion thrusters, hollow cathodes, field effect emitters, plasma contactors, etc.); - possible studies relevant to fundamental space plasma physics. The facility consists of a large volume vacuum tank (a cylinder of length 4.5 m and diameter 1.7 m) equipped with a Kaufman type plasma source, operating with Argon gas, capable to generate a plasma beam with parameters (i.e. density and electron temperature) close to the values encountered in the ionosphere at F layer altitudes. The plasma beam (A+ ions and electrons) is accelerated into the chamber at a velocity that reproduces the relative motion between an orbiting satellite and the ionosphere (≈ 8 km/s). This feature, in particular, allows laboratory simulations of the actual compression and depletion phenomena which take place in the ram and wake regions around satellites moving through the ionosphere. The reproduced plasma environment is monitored using Langmuir Probes (LP) and Retarding Potential Analyzers (RPA). These sensors can be automatically moved within the experimental space using a sled mechanism. Such a feature allows the acquisition of the plasma parameters all around the space payload installed into the chamber for testing. The facility is currently in use to test the payloads of CSES satellite (Chinese Seismic Electromagnetic Satellite) devoted to plasma parameters and electric field

  12. THEOS: The1st Thailand EO System and

    NASA Astrophysics Data System (ADS)

    Peanvijarnpong, Chanchai

    Thailand has engaged in remote sensing satellite technological and scientific development many years since early 1980s. Thailand Landsat Station was established as a regional center of data processing and dissemination for Thai scientists for data applications. Over the years, GISTDA and Thai user community have been gaining technical experience and expertise in satellite data applications around the country such natural resources and environmental management, forest inventory, forest change detections, soil mapping, land-use and land cover mapping, crop type mapping, coastal shrimp farming, flood zone mapping, base mapping, water and drought management. The Government of Thailand realizes that remote sensing satellite technology is an important mechanism for social and economic development of the country. So the 1st Thailand Earth Observation System (THEOS) development program was approved by the Government since 2003. THEOS system is sub-synchronous satellite orbiting around the earth at 822 km. altitude same as SPOT satellites. It carries two imaging instruments; 2-m Panchromatic telescope with 22 km. swath width and 15-m resolution camera with four-multi-spectral band and 90-km swath wide. THEOS is scheduled to launch around March 2008. A number of technological and scientific activities has been implementing for Thailand and international scientific user community. Therefore THEOS is strong endorsement from the Government of Thailand on the value of remote sensing technology. This paper presents Thailand EO activities including THEOS System and its plans.

  13. 1st Advanced Marine Renewable Energy Instrumentation Experts Workshop

    SciTech Connect

    none,

    2011-10-01

    The U.S. marine energy industry is actively pursuing development of offshore wind and marine hydrokinetic (MHK) energy systems. Experience in the wind energy sector demonstrates that new technology development requires thorough measurement and characterization of the environmental conditions prevalent at installation sites and of technology operating in the field. Presently, there are no turn-key instrumentation system solutions that meet the measurement needs of the marine energy industry. The 1st Advanced Marine Renewable Energy Instrumentation Experts Workshop brought together technical experts from government laboratories, academia, and industry representatives from marine energy, wind, offshore oil and gas, and instrumentation developers to present and discuss the instrumentation needs of the marine energy industry. The goals of the meeting were to: 1. Share the latest relevant knowledge among technical experts; 2. Review relevant state-of-the-art field measurement technologies and methods; 3. Review lessons learned from recent field deployments; 4. Identify synergies across different industries; 5. Identify gaps between existing and needed instrumentation capabilities; 6. Understand who are the leading experts; 7. Provide a forum where stakeholders from the marine energy industry could provide substantive input in the development of new marine energy field deployable instrumentation packages.

  14. Electron Diffraction Experiments using Laser Plasma Electrons

    SciTech Connect

    Fill, E E; Trushin, S; Tommasini, R; Bruch, R

    2005-09-07

    We demonstrate that electrons emitted from a laser plasma can be used to generate diffraction patterns in reflection and transmission. The electrons are emitted in the direction of laser polarization with energies up to 100 keV. The broad electron energy spectrum makes possible the generation of a ''streaked'' diffraction pattern which allows recording fast processes in a single run.

  15. Production of Uniform Dense Titanium Plasmas for Experiments on Atlas

    NASA Astrophysics Data System (ADS)

    Wysocki, Frederick J.; Benage, John F.; Newton, Robert R.; Wood, Blake P.

    2000-10-01

    Atlas is a large pulsed power machine being built at Los Alamos for the purpose of doing basic physics and hydrodynamic experiments for the stockpile stewardship program. One class of the basic physics experiments involves studying the properties and behavior of plasmas at very high density. These experiments will typically involve the production of a high density plasma to be imploded by the solid liners driven by the Atlas machine. The requirements for these high density ``target" plasmas are that they be uniform in density and temperature, have ion densities ≈ 0.1 x solid density, and temperatures of a few eV. The production of such plasmas has not been demonstrated; therefore, we have initiated an experimental program to learn to do this. We are conducting a series of experiments on the Colt capacitor bank at Los Alamos. These experiments use a novel configuration to heat a titanium foil to plasma conditions using the current from Colt, but without imploding the plasma. We will present preliminary density profiles of the titanium plasma using x-ray radiography along with magnetic probe data showing the current distribution in the machine. Measurements of the electrical resistivity of titanium under these conditions will also be presented.

  16. Production of Uniform Dense Plasmas for Experiments on Atlas

    NASA Astrophysics Data System (ADS)

    Wysocki, Frederick J.; Benage, John F.; Newton, Robert R.

    1999-11-01

    Atlas is a large pulsed power machine being built at Los Alamos for the purpose of doing basic physics and hydrodynamic experiments for the stockpile stewardship program. One class of the basic physics experiments involves studying the properties and behavior of plasmas at very high density. These experiments will typically involve the production of a high density plasma to be imploded by the solid liners driven by the Atlas machine. The requirements for these high density ``target" plasmas are that they be uniform in density and temperature, have ion densities 0.1 x solid density, and temperatures of a few eV. The production of such plasmas has not been demonstrated; therefore, we have initiated an experimental program to learn to do this. We are conducting a series of experiments on the Colt capacitor bank at Los Alamos. These experiments use a novel configuration to heat a titanium foil to plasma conditions using the current from Colt, but without imploding the plasma. We will present preliminary density profiles of the titanium plasma using x-ray radiography along with magnetic probe data showing the current distribution in the machine.

  17. Progress toward positron-electron pair plasma experiments

    SciTech Connect

    Stenson, E. V.; Stanja, J.; Hergenhahn, U.; Saitoh, H.; Niemann, H.; Pedersen, T. Sunn; Marx, G. H.; Schweikhard, L.; Danielson, J. R.; Surko, C. M.; Hugenschmidt, C.

    2015-06-29

    Electron-positron plasmas have been of theoretical interest for decades, due to the unique plasma physics that arises from all charged particles having precisely identical mass. It is only recently, though, that developments in non-neutral plasma physics (both in linear and toroidal geometries) and in the flux of sources for cold positrons have brought the goal of conducting electron-positron pair plasma experiments within reach. The APEX/PAX collaboration is working on a number of projects in parallel toward that goal; this paper provides an overview of recent, current, and upcoming activities.

  18. The ISPM unified radio and plasma wave experiment

    NASA Technical Reports Server (NTRS)

    Stone, R. G.; Caldwell, J.; Deconchy, Y.; Deschanciaux, C.; Ebbett, R.; Epstein, G.; Groetz, K.; Harvey, C. C.; Hoang, S.; Howard, R.

    1983-01-01

    Hardware for the International Solar Polar Mission (ISPM) Unified Radio and Plasma (URAP) wave experiment is presented. The URAP determines direction and polarization of distant radio sources for remote sensing of the heliosphere, and studies local wave phenomena which determine the transport coefficients of the ambient plasma. Electric and magnetic field antennas and preamplifiers; the electromagnetic compatibility plan and grounding; radio astronomy and plasma frequency receivers; a fast Fourier transformation data processing unit waveform analyzer; dc voltage measurements; a fast envelope sampler for the solar wind, and plasmas near Jupiter; a sounder; and a power converter are described.

  19. Diagnosis in Complex Plasmas for Microgravity Experiments (PK-3 plus)

    SciTech Connect

    Takahashi, Kazuo; Hayashi, Yasuaki; Thomas, Hubertus M.; Morfill, Gregor E.; Ivlev, Alexei V.; Adachi, Satoshi

    2008-09-07

    Microgravity gives the complex (dusty) plasmas, where dust particles are embedded in complete charge neutral region of bulk plasma. The dust clouds as an uncompressed strongly coupled Coulomb system correspond to atomic model with several physical phenomena, crystallization, phase transition, and so on. As the phenomena tightly connect to plasma states, it is significant to understand plasma parameters such as electron density and temperature. The present work shows the electron density in the setup for microgravity experiments currently onboard on the International Space Station.

  20. The Thermal Ion Dynamics Experiment and Plasma Source Instrument

    NASA Technical Reports Server (NTRS)

    Moore, T. E.; Chappell, C. R.; Chandler, M. O.; Fields, S. A.; Pollock, C. J.; Reasoner, D. L.; Young, D. T.; Burch, J. L.; Eaker, N.; Waite, J. H., Jr.; McComas, D. J.; Nordholdt, J. E.; Thomsen, M. F.; Berthelier, J. J.; Robson, R.

    1995-01-01

    The Thermal Ion Dynamics Experiment (TIDE) and the Plasma Source Instrument (PSI) have been developed in response to the requirements of the ISTP Program for three-dimensional (3D) plasma composition measurements capable of tracking the circulation of low-energy (0-500 eV) plasma through the polar magnetosphere. This plasma is composed of penetrating magnetosheath and escaping ionospheric components. It is in part lost to the downstream solar wind and in part recirculated within the magnetosphere, participating in the formation of the diamagnetic hot plasma sheet and ring current plasma populations. Significant obstacles which have previously made this task impossible include the low density and energy of the outflowing ionospheric plasma plume and the positive spacecraft floating potentials which exclude the lowest-energy plasma from detection on ordinary spacecraft. Based on a unique combination of focusing electrostatic ion optics and time of flight detection and mass analysis, TIDE provides the sensitivity (seven apertures of about 1 cm squared effective area each) and angular resolution (6 x 18 degrees) required for this purpose. PSI produces a low energy plasma locally at the POLAR spacecraft that provides the ion current required to balance the photoelectron current, along with a low temperature electron population, regulating the spacecraft potential slightly positive relative to the space plasma. TIDE/PSI will: (a) measure the density and flow fields of the solar and terrestrial plasmas within the high polar cap and magnetospheric lobes; (b) quantify the extent to which ionospheric and solar ions are recirculated within the distant magnetotail neutral sheet or lost to the distant tail and solar wind; (c) investigate the mass-dependent degree energization of these plasmas by measuring their thermodynamic properties; (d) investigate the relative roles of ionosphere and solar wind as sources of plasma to the plasma sheet and ring current.

  1. Contoured-gap coaxial guns for imploding plasma liner experiments

    NASA Astrophysics Data System (ADS)

    Witherspoon, F. D.; Case, A.; Brockington, S.; Cassibry, J. T.; Hsu, S. C.

    2014-10-01

    Arrays of supersonic, high momentum flux plasma jets can be used as standoff compression drivers for generating spherically imploding plasma liners for driving magneto-inertial fusion, hence the name plasma-jet-driven MIF (PJMIF). HyperV developed linear plasma jets for the Plasma Liner Experiment (PLX) at LANL where two guns were successfully tested. Further development at HyperV resulted in achieving the PLX goal of 8000 μg at 50 km/s. Prior work on contoured-gap coaxial guns demonstrated an approach to control the blowby instability and achieved substantial performance improvements. For future plasma liner experiments we propose to use contoured-gap coaxial guns with small Minirailgun injectors. We will describe such a gun for a 60-gun plasma liner experiment. Discussion topics will include impurity control, plasma jet symmetry and topology (esp. related to uniformity and compactness), velocity capability, and techniques planned for achieving gun efficiency of >50% using tailored impedance matched pulse forming networks. Mach2 and UAH SPH code simulations will be included. Work supported by US DOE DE-FG02-05ER54810.

  2. Plasma lens experiments at the Final Focus Test Beam

    SciTech Connect

    Barletta, B. |; Chattopadhyay, S.; Chen, P.

    1993-04-01

    We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam ionization of a working gas. At an increased bunch population of 2.5 {times} 10{sup 10}, tunneling ionization of a gas target by an electron beam -- an effect which has never been observed before -- should be significant. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders.

  3. Plasma lens experiments at the final focus test beam

    SciTech Connect

    Barletta, W.; Chattopadhyay, S.; Chen, P.

    1995-02-01

    The authors intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. They will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam induced tunneling ionization of a working gas--the latter which has never been observed before. The compactness of the device should prove to be of interest for applications at the SLC and the next generation linear colliders.

  4. Status of Magnetic Nozzle and Plasma Detachment Experiment

    SciTech Connect

    Chavers, D. Gregory; Dobson, Chris; Jones, Jonathan; Lee, Michael; Martin, Adam; Gregory, Judith; Cecil, Jim; Bengtson, Roger D.; Breizman, Boris; Arefiev, Alexey; Chang-Diaz, Franklin; Squire, Jared; Glover, Tim; McCaskill, Greg; Cassibry, Jason; Li Zhongmin

    2006-01-20

    High power plasma propulsion can move large payloads for orbit transfer, lunar missions, and beyond with large savings in fuel consumption owing to the high specific impulse. At high power, lifetime of the thruster becomes an issue. Electrodeless devices with magnetically guided plasma offer the advantage of long life since magnetic fields confine the plasma radially and keep it from impacting the material surfaces. For decades, concerns have been raised about the plasma remaining attached to the magnetic field and returning to the vehicle along the closed magnetic field lines. Recent analysis suggests that this may not be an issue if the magnetic field is properly shaped in the nozzle region and the plasma has sufficient energy density to stretch the magnetic field downstream. An experiment is being performed to test the theory regarding the MHD detachment scenario. The status of that experiment will be discussed in this paper.

  5. MHD Experiment At CIRA GHIBLI Plasma Wind Tunnel

    NASA Astrophysics Data System (ADS)

    Trifoni, E.; Purpura, C.; Martucci, A.; Graps, E.; Schettino, A.; Battista, F.; Passaro, A.; Baccarella, D.; Cristofolini, A.; Neretti, G.

    2011-05-01

    A Test campaign in the frame of the ASI (Italian Space Agency) funded project CAST (Advanced Aerothermodynamic Configurations for Space Transport) was performed at the CIRA GHIBLI plasma wind tunnel. The CAST Test campaign in GHIBLI consisted of more than 20 test cases including Probe measurements, microwave absorption measurements and a MHD experiment. The microwave absorption measurements were performed in plasma free jet conditions in order to determine the integral electron number density of the plasma flow. A correlation between the measured electron number density and the facility operating conditions was found. The MHD experiment was performed by insertion in the hypersonic plasma jet of a ceramic flat faced blunt cone model containing a permanent magnet inside, able to generate a magnetic field of 0.5 Tesla; also another model identical to the previous but not containing any magnet inside, was inserted in the hypersonic plasma jet at the same flow conditions. The effects of such interactions were compared.

  6. Particle Probe Investigations on the Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    Sherman, Justin; James, R. W.; Lopez, M.; Nolan, S.; Page, E. L.; Schlank, C.; Stutzman, B. S.; Zuniga, J.

    2012-10-01

    A small Helicon Plasma Experiment (HPX) has been constructed at the Coast Guard Academy Plasma Lab (CGAPL) to utilize the reputed high densities at low pressure (.01 T) [1], in high temperature and density diagnostic development for future laboratory investigations. With the initial construction phase complete, HPX has produced its first plasmas. Efforts to develop and enhance the high temperature and density (10^13 cm-3 and higher) helicon plasmas at low pressures (.01 T) reported by Toki, Shinohara, et. al. continue. Currently, particle probes to measure plasmas' temperatures and densities, necessary to discern the plasma mode transitions, are in development. Construction of independent mach and triple probes for single point surface investigations are underway and once installed, they will be followed by a triple probe array to produce a more comprehensive density and surface view. Progress on the construction and findings of these probes on HPX will be reported.

  7. Compact collimated fiber optic array diagnostic for railgun plasma experiments

    SciTech Connect

    Tang, V; Solberg, J; Ferriera, T; Tully, L; Stephan, P

    2008-10-02

    We have developed and tested a compact collimated sixteen channel fiber optic array diagnostic for studying the light emission of railgun armature plasmas with {approx}mm spatial and sub-{micro}s temporal resolution. The design and operational details of the diagnostic are described. Plasma velocities, oscillation, and dimension data from the diagnostic for the Livermore Fixed Hybrid Armature experiment are presented and compared with 1-D simulations. The techniques and principles discussed allow the extension of the diagnostic to other railgun and related dense plasma experiments.

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

    SciTech Connect

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

    2013-01-15

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

  9. Comparing simulation of plasma turbulence with experiment

    NASA Astrophysics Data System (ADS)

    Ross, David W.; Bravenec, Ronald V.; Dorland, William; Beer, Michael A.; Hammett, G. W.; McKee, George R.; Fonck, Raymond J.; Murakami, Masanori; Burrell, Keith H.; Jackson, Gary L.; Staebler, Gary M.

    2002-01-01

    The direct quantitative correspondence between theoretical predictions and the measured plasma fluctuations and transport is tested by performing nonlinear gyro-Landau-fluid simulations with the GRYFFIN (or ITG) code [W. Dorland and G. W. Hammett, Phys. Fluids B 5, 812 (1993); M. A. Beer and G. W. Hammett, Phys. Plasmas 3, 4046 (1996)]. In an L-mode reference discharge in the DIII-D tokamak [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)], which has relatively large fluctuations and transport, the turbulence is dominated by ion temperature gradient (ITG) modes. Trapped electron modes and impurity drift waves also play a role. Density fluctuations are measured by beam emission spectroscopy [R. J. Fonck, P. A. Duperrex, and S. F. Paul, Rev. Sci. Instrum. 61, 3487 (1990)]. Experimental fluxes and corresponding diffusivities are analyzed by the TRANSP code [R. J. Hawryluk, in Physics of Plasmas Close to Thermonuclear Conditions, edited by B. Coppi, G. G. Leotta, D. Pfirsch, R. Pozzoli, and E. Sindoni (Pergamon, Oxford, 1980), Vol. 1, p. 19]. The shape of the simulated wave number spectrum is close to the measured one. The simulated ion thermal transport, corrected for E×B low shear, exceeds the experimental value by a factor of 1.5 to 2.0. The simulation overestimates the density fluctuation level by an even larger factor. On the other hand, the simulation underestimates the electron thermal transport, which may be accounted for by modes that are not accessible to the simulation or to the BES measurement.

  10. Review of high-energy plasma wakefield experiments

    NASA Astrophysics Data System (ADS)

    Muggli, Patric; Hogan, Mark J.

    2009-03-01

    Plasma wakefield accelerator (PWFA) experiments have made considerable progress in the past decade by using high-energy particle beams to drive large amplitude waves or wakes in a plasma. Electron beam driven experiments have measured the integrated and dynamic aspects of plasma focusing, the bright flux of high-energy betatron radiation photons, particle beam refraction at the plasma/neutral gas interface, and the structure and amplitude of the accelerating wakefield. Gradients spanning kT/m to MT/m for focusing and 100 MeV/m to 50 GeV/m for acceleration have been excited in plasmas with densities of 10 14 to 10 cm, respectively. The large accelerating gradient led to the energy doubling of 42 GeV electrons in only 85 cm of plasma. Positron beam driven experiments have evidenced the comparatively more complex dynamic and integrated plasma focusing, the subsequent halo formation and emittance growth in the positron beam and demonstrated accelerating gradients of nearly 100 MeV/m. This article summarizes this experimental progress, illustrates the key enabling technologies that made the work possible, concludes with a brief discussion of proposed future directions, and suggests that the PWFA could one day revolutionize e/e linear colliders. To cite this article: P. Muggli, M.J. Hogan, C. R. Physique 10 (2009).

  11. Spectroscopic measurements of plasma emission light for plasma-based acceleration experiments

    NASA Astrophysics Data System (ADS)

    Filippi, F.; Anania, M. P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Ferrario, M.; Mostacci, A.; Palumbo, L.; Zigler, A.

    2016-09-01

    Advanced particle accelerators are based on the excitation of large amplitude plasma waves driven by either electron or laser beams. Future experiments scheduled at the SPARC_LAB test facility aim to demonstrate the acceleration of high brightness electron beams through the so-called resonant Plasma Wakefield Acceleration scheme in which a train of electron bunches (drivers) resonantly excites wakefields into a preformed hydrogen plasma; the last bunch (witness) injected at the proper accelerating phase gains energy from the wake. The quality of the accelerated beam depends strongly on plasma density and its distribution along the acceleration length. The measurements of plasma density of the order of 1016-1017 cm-3 can be performed with spectroscopic measurements of the plasma-emitted light. The measured density distribution for hydrogen filled capillary discharge with both Balmer alpha and Balmer beta lines and shot-to-shot variation are here reported.

  12. A 1D (radial) Plasma Jet Propagation Study for the Plasma Liner Experiment (PLX)

    NASA Astrophysics Data System (ADS)

    Thompson, J. R.; Bogatu, I. N.; Galkin, S. A.; Kim, J. S.; Welch, D. R.; Thoma, C.; Golovkin, I.; Macfarlane, J. J.; Case, A.; Messer, S. J.; Witherspoon, F. D.; Cassibry, J. T.; Awe, T. J.; Hsu, S. C.

    2011-10-01

    The Plasma Liner Experiment will explore the formation of imploding spherical ``plasma liners'' that reach peak pressures of 0.1 Mbar upon stagnation. The liners will be formed through the merging of dense, high velocity plasma jets (n ~1017 cm-3, T ~3 eV, v ~50 km/s) in a spherically convergent geometry. The focus of this 1D (radial) study is argon plasma jet evolution during propagation from the rail gun source to the jet merging radius. The study utilizes the Large Scale Plasma (LSP) PIC code with atomic physics included through the use of a non-Local Thermal Equilibrium (NLTE) Equation of State (EOS) table. We will present scenarios for expected 1D (radial) plasma jet evolution, from upon exiting the PLX rail gun to reaching the jet merging radius. The importance of radiation cooling early in the simulation is highlighted. Work supported by US DOE grant DE-FG02-05ER54835.

  13. Plasma Motor Generator (PMG) electrodynamic tether experiment

    NASA Technical Reports Server (NTRS)

    Grossi, Mario D.

    1995-01-01

    The Plasma Motor Generator (PMG) flight of June 26, 1993 has been the most sophisticated and most successful mission that has been carried out thus far with an electrodynamic tether. Three papers from the Smithsonian Astrophysical Observatory, Washington, DC concerned with the PMG, submitted at the Fourth International Space Conference on Tethers in Space, in Washington, DC, in April 1995, are contained in this document. The three papers are (1) Electromagnetic interactions between the PMG tether and the magneto-ionic medium of the Ionosphere; (2) Tether-current-voltage characteristics, as determined by the Hollow Cathode Operation Modes; and (3) Hawaii-Hilo ground observations on the occasion for the PMG flight of June 23, 1993.

  14. Solvent/detergent plasma: pharmaceutical characteristics and clinical experience.

    PubMed

    Liumbruno, Giancarlo Maria; Franchini, Massimo

    2015-01-01

    The solvent/detergent treatment is an established virus inactivation technology that has been industrially applied for manufacturing plasma derived medicinal products for almost 30 years. Solvent/detergent plasma is a pharmaceutical product with standardised content of clotting factors, devoid of antibodies implicated in transfusion-related acute lung injury pathogenesis, and with a very high level of decontamination from transfusion-transmissible infectious agents. Many clinical studies have confirmed its safety and efficacy in the setting of congenital as well as acquired bleeding disorders. This narrative review will focus on the pharmaceutical characteristics of solvent/detergent plasma and the clinical experience with this blood product.

  15. Tritium Plasma Experiment Upgrade for Fusion Tritium and Nuclear Sciences

    NASA Astrophysics Data System (ADS)

    Shimada, Masashi; Taylor, Chase N.; Kolasinski, Robert D.; Buchenauer, Dean A.

    2015-11-01

    The Tritium Plasma Experiment (TPE) is a unique high-flux linear plasma device that can handle beryllium, tritium, and neutron-irradiated plasma facing materials, and is the only existing device dedicated to directly study tritium retention and permeation in neutron-irradiated materials [M. Shimada et.al., Rev. Sci. Instru. 82 (2011) 083503 and and M. Shimada, et.al., Nucl. Fusion 55 (2015) 013008]. Recently the TPE has undergone major upgrades in its electrical and control systems. New DC power supplies and a new control center enable remote plasma operations from outside of the contamination area for tritium, minimizing the possible exposure risk with tritium and beryllium. We discuss the electrical upgrade, enhanced operational safety, improved plasma performance, and development of tritium plasma-driven permeation and optical spectrometer system. This upgrade not only improves operational safety of the worker, but also enhances plasma performance to better simulate extreme plasma-material conditions expected in ITER, Fusion Nuclear Science Facility (FNSF), and Demonstration reactor (DEMO). This work was prepared for the U.S. Department of Energy, Office of Fusion Energy Sciences, under the DOE Idaho Field Office contract number DE-AC07-05ID14517.

  16. US/Russian Magnetized Target Fusion Plasma Formation Experiments

    NASA Astrophysics Data System (ADS)

    Benage, John F., Jr.; Mtf Team; Broste, W.; Westley, D.; Mago Team

    1998-11-01

    Magnetized target fusion (MTF) is a potentially very low cost route to producing a fusion energy source. Many of MTF's plasma properties are intermediate between magnetically confined fusion (MFE) and inertially confined fusion (ICF). MTF consists of first producing a magnetically thermally insulated target plasma with a temperature of 100 eV or more with a lifetime of 5-10 microseconds. The target plasma is then compressed to fusion conditions by a magnetically driven imploding liner. One target plasma candidate is VNIIEF's MAGO, in which a cylindrical chamber with two cavities is filled with DT gas at a pressure of 10 Torr and driven by a current of 2-8 MA. A series of experiments under different plasma conditions have been performed to evaluate MAGO as an MTF target plasma. Diagnostics used to characterize the MAGO plasma include B dot probes to measure the current distribution, filtered silicon diodes to measure the spectrum and duration of the plasma radiation and a UV spectrometer to measure impurity line radiation.

  17. RF experiments on spherical torus plasmas

    SciTech Connect

    Majeski, R.; Menard, J.; Batchelor, D.; Bigelow, T.; Carter, M. D.; Finkenthal, M.; Jaeger, E. F.; Jones, B.; Kaita, R.; Mau, T. K.

    1999-09-20

    Experimental operations are about to begin on the next generation of spherical torus (ST) devices-the National Spherical Torus eXperiment (NSTX) in the U.S. and the Mega-Amp Spherical Torus (MAST) in the U.K. The application of RF heating and current drive to these high beta, compact confinement devices is a challenging problem. The initial focus for NSTX had been on the High Harmonic Fast Wave (HHFW) regime. Although modeling of HHFW heating and current drive has been performed at ORNL, UCSD, MIT, and PPPL, there are few experiments in this frequency range. In conventional tokamaks, the DIII-D experiments at the 5{sup th}-7{sup th} cyclotron harmonic are the closest approach to the HHFW regime. In an ST, the only RF heating experiments to date have been performed at the 15{sup th} harmonic on the Current Drive eXperiment-Upgrade (CDX-U) at PPPL. General features of HHFW heating and current drive and the degree to which experimental confirmation of these features is available will be discussed. (c) 1999 American Institute of Physics.

  18. 1st HPV Test for Use with Preservative Fluid

    MedlinePlus

    ... 159789.html 1st HPV Test for Use With Preservative Fluid Human papillomavirus responsible for 70 percent of ... Roberts Friday, July 8, 2016 FRIDAY, July 8, 2016 (HealthDay News) -- The U.S. Food and Drug Administration has approved Roche's cobas HPV ...

  19. Trends in laser-plasma-instability experiments for laser fusion

    SciTech Connect

    Drake, R.P. Lawrence Livermore National Lab., CA )

    1991-06-06

    Laser-plasma instability experiments for laser fusion have followed three developments. These are advances in the technology and design of experiments, advances in diagnostics, and evolution of the design of high-gain targets. This paper traces the history of these three topics and discusses their present state. Today one is substantially able to produce controlled plasma conditions and to diagnose specific instabilities within such plasmas. Experiments today address issues that will matter for future laser facilities. Such facilities will irradiate targets with {approx}1 MJ of visible or UV light pulses that are tens of nanoseconds in duration, very likely with a high degree of spatial and temporal incoherence. 58 refs., 4 figs.

  20. Solar Array Module Plasma Interaction Experiment (SAMPIE): Technical requirements document

    NASA Technical Reports Server (NTRS)

    Hillard, G. Barry; Ferguson, Dale C.

    1992-01-01

    The Solar Array Module Plasma Interactions Experiment (SAMPIE) is a NASA shuttle space flight experiment scheduled for launch in early 1994. The SAMPIE experiment will investigate plasma interactions of high voltage space power systems in low earth orbit. Solar cell modules, representing several technologies, will be biased to high voltages to characterize both arcing and plasma current collection. Other solar modules, specially modified in accordance with current theories of arcing and breakdown, will demonstrate the possibility of arc suppression. Finally, several test modules will be included to study the basic nature of these interactions. The science and technology goals for the project are defined in the Technical Requirements Document (TRD) which is presented here.

  1. Freestanding film structures for laser plasma experiments

    SciTech Connect

    Klyuenkov, E B; Lopatin, A Ya; Luchin, V I; Salashchenko, Nikolai N; Tsybin, N N

    2013-04-30

    The technique is developed for fabricating 5-500-nm-thick freestanding films of various materials and multilayer compositions. Apart from the traditional use in spectral filtration of soft X-ray and extreme ultraviolet radiation, the possibility of using the ultrathin films fabricated by this technique as targets in experiments on laser acceleration of ions is considered. A sample of the target in the form of a 5-nm-thick carbon film on a supporting net is fabricated. (extreme light fields and their applications)

  2. Hybrid-PIC Algorithms for Simulation of Merging Plasma Jets in the Plasma Liner Experiment

    NASA Astrophysics Data System (ADS)

    Thoma, Carsten; Welch, Dale; Clark, Robert; Macfarlane, Joseph; Golovkin, Igor; Witherspoon, F. Douglas

    2010-11-01

    In the upcoming Plasma Liner Experiment (PLX) at Los Alamos National Laboratory a spherical array of 30-60 jets generated by plasma guns will be merged to form imploding plasma liners. We describe the Hybrid particle-in-cell (PIC) methods implemented in the code LSP for plasma jet simulation and present results of simulations of merging Ar jets. Electron macroparticles are treated as fluid elements which carry an intrinsic temperature while ion macroparticles are treated kinetically. The effective charge state is obtained from EOS tables as a function of the local plasma parameters under the assumption of local thermodynamic equilibrium (LTE). The effect of radiation cooling on the electrons is also included self-consistently into the Hybrid PIC formalism. The LSP results of jet merging simulations will be post-processed using the SPECT3D code to generate simulated radiation flux levels, spectra and images (MacFarlane et al., this meeting).

  3. Plasma production for the 50 MeV plasma lens experiment at LBL

    SciTech Connect

    Leemans, W.; van der Geer, B.; de Loos, M.; Conde, M.; Govil, R.; Chattopadhyay, S.

    1994-06-01

    The Center for Beam Physics at LBL has constructed a Beam Test Facility (BTF) housing a 50 MeV electron beam transport line, which uses the linac injector from the Advanced Light Source, and a terawatt Ti:Al{sub 2}O{sub 3} laser system. The linac operates at 50 MeV and generates 15 ps long electron bunches containing a charge of up to 2 nC. The measured unnormalized beam emittance is 0.33 mm-mrad. These parameters allow for a comprehensive study of focusing of relativistic electron beams with plasma columns, in both the overdense and underdense regime (adiabatic and tapered lenses). A study of adiabatic and/or tapered lenses requires careful control of plasma density and scale lengths of the plasma. We present experimental results on the production of plasmas through resonant two-photon ionization, with parameters relevant to an upcoming plasma lens experiment.

  4. Particle Probe Investigations on the Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    Sherman, Justin; James, R. W.; Nolan, S.; Page, E. J.; Romano, B.; Zuniga, J.; Schlank, C.; Lopez, M.; Karama, J.; Duke-Tinson, O.; Stutzman, B. S.

    2013-10-01

    Coast Guard Academy Plasma Lab(CGAPL) has constructed a Helicon Plasma Experiment. Plasmas will be used in high-temperature and -density diagnostic development for future lab investigations of fusion-grade plasma. Efforts to develop and enhance high temperature and density (1013cm-3 and up) helicon plasmas at low pressures (.01T) reported by Toki et al., continue. HPX will integrate a 32-channel National Instruments DAQ(Data Acquisition) board, designed to digitize data from tests. With LabView as the programing language, CGAPL will take samples at 12bits of precision at 2MS/s to create a Graphical User Interface (GUI). The GUI will control experimental variables (one or several concurrent tests) and monitor systems during data collection. Data collection will be conducted with particle probes, currently under construction. Probes, used to discern the plasma mode transitions, will measure plasma particle velocity, temperature, density and floating potential at different regimes. Once independent triple and mach probes for surface point investigations are installed, a triple probe array to produce a more comprehensive density and surface view will follow. Progress on development of GUI and construction of probes will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY12.

  5. The Material Plasma Exposure eXperiment (MPEX)

    NASA Astrophysics Data System (ADS)

    Rapp, J.; Biewer, T. M.; Bigelow, T. S.; Canik, J.; Caughman, J. B. O.; Duckworth, R. C.; Goulding, R. H.; Hillis, D. L.; Lore, J. D.; Lumsdaine, A.; McGinnis, W. D.; Meitner, S. J.; Owen, L. W.; Shaw, G. C.; Luo, G.-N.

    2014-10-01

    Next generation plasma generators have to be able to access the plasma conditions expected on the divertor targets in ITER and future devices. The Material Plasma Exposure eXperiment (MPEX) will address this regime with electron temperatures of 1--10 eV and electron densities of 1021--1020 m-3. The resulting heat fluxes are about 10 MW/m2. MPEX is designed to deliver those plasma conditions with a novel Radio Frequency plasma source able to produce high density plasmas and heat electron and ions separately with Electron Bernstein Wave (EBW) heating and Ion Cyclotron Resonance Heating (ICRH). Preliminary modeling has been used for pre-design studies of MPEX. MPEX will be capable to expose neutron irradiated samples. In this concept targets will be irradiated in ORNL's High Flux Isotope Reactor (HFIR) or possibly at the Spallation Neutron Source (SNS) and then subsequently (after a sufficient long cool-down period) exposed to fusion reactor relevant plasmas in MPEX. The current state of the pre-design of MPEX including the concept of handling irradiated samples will be presented. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under Contract DE-AC-05-00OR22725.

  6. Telescience operations with the solar array module plasma interaction experiment

    NASA Technical Reports Server (NTRS)

    Wald, Lawrence W.; Bibyk, Irene K.

    1995-01-01

    The Solar Array Module Plasma Interactions Experiment (SAMPIE) is a flight experiment that flew on the Space Shuttle Columbia (STS-62) in March 1994, as part of the OAST-2 mission. The overall objective of SAMPIE was to determine the adverse environmental interactions within the space plasma of low earth orbit (LEO) on modern solar cells and space power system materials which are artificially biased to high positive and negative direct current (DC) voltages. The two environmental interactions of interest included high voltage arcing from the samples to the space plasma and parasitic current losses. High voltage arcing can cause physical damage to power system materials and shorten expected hardware life. parasitic current losses can reduce power system efficiency because electric currents generated in a power system drain into the surrounding plasma via parasitic resistance. The flight electronics included two programmable high voltage DC power supplies to bias the experiment samples, instruments to measure the surrounding plasma environment in the STS cargo bay, and the on-board data acquisition system (DAS). The DAS provided in-flight experiment control, data storage, and communications through the Goddard Space Flight Center (GSFC) Hitchhiker flight avionics to the GSFC Payload Operations Control Center (POCC). The DAS and the SAMPIE POCC computer systems were designed for telescience operations; this paper will focus on the experiences of the SAMPIE team regarding telescience development and operations from the GSFC POCC during STS-62. The SAMPIE conceptual development, hardware design, and system verification testing were accomplished at the NASA Lewis Research Center (LeRC). SAMPIE was developed under the In-Space Technology Experiment Program (IN-STEP), which sponsors NASA, industry, and university flight experiments designed to enable and enhance space flight technology. The IN-STEP Program is sponsored by the Office of Space Access and Technology (OSAT).

  7. Experiment and simulation on one-dimensional plasma photonic crystals

    SciTech Connect

    Zhang, Lin; Ouyang, Ji-Ting

    2014-10-15

    The transmission characteristics of microwaves passing through one-dimensional plasma photonic crystals (PPCs) have been investigated by experiment and simulation. The PPCs were formed by a series of discharge tubes filled with argon at 5 Torr that the plasma density in tubes can be varied by adjusting the discharge current. The transmittance of X-band microwaves through the crystal structure was measured under different discharge currents and geometrical parameters. The finite-different time-domain method was employed to analyze the detailed properties of the microwaves propagation. The results show that there exist bandgaps when the plasma is turned on. The properties of bandgaps depend on the plasma density and the geometrical parameters of the PPCs structure. The PPCs can perform as dynamical band-stop filter to control the transmission of microwaves within a wide frequency range.

  8. Alpha-particle Measurements Needed for Burning Plasma Experiments

    SciTech Connect

    Kenneth M. Young

    2001-09-26

    The next major step in magnetic fusion studies will be the construction of a burning plasma (BP) experiment where the goals will be to achieve and understand the plasma behavior with the internal heating provided by fusion-generated alpha particles. Two devices with these physics goals have been proposed: the International Thermonuclear Experimental Reactor (ITER) and the Fusion Ignition Research Experiment (FIRE). Extensive conceptual design work for the instrumentation to try to meet the physics demands has been done for these devices, especially ITER. This article provides a new look at the measurements specifically important for understanding the physics aspects of the alpha particles taking into account two significant events. The first is the completion of physics experiments on the Joint European Torus (JET) and the Tokamak Fusion Test Reactor (TFTR) with deuterium-tritium fueling with the first chances to study alpha physics and the second is the realization that relatively compact plasmas, making use of advanced tokamak plasma concepts, are the most probable route to burning plasmas and ultimately a fusion reactor.

  9. Simulation studies of plasma lens experiments at Daresbury laboratory

    NASA Astrophysics Data System (ADS)

    Hanahoe, K.; Mete, O.; Xia, G.; Angal-Kalinin, D.; Jones, J.; Smith, J.

    2016-03-01

    Experiments are planned to study plasma lensing using the VELA and CLARA Front End accelerators at Daresbury Laboratory. This paper presents results of 2-dimensional particle-in-cell simulations of the proposed experiments. The variation in focusing strength and emittance growth with beam and plasma parameters are studied in the overdense (plasma density much greater than bunch density) regime for the VELA beam. The effect of spherical and longitudinal aberrations on the beam emittance was estimated through numerical and theoretical studies. Simulation results show that a focusing strength equivalent to a magnetic field gradient of 10 T m-1 can be achieved using VELA, and a gradient of 247 T m-1 can be achieved using CLARA Front End.

  10. Plasma flow switch and foil implosion experiments on Pegasus 2

    NASA Astrophysics Data System (ADS)

    Cochrane, J. C.; Bartsch, R. R.; Benage, J. R.; Forman, P. R.; Gribble, R. F.; Ladish, J. S.; Oona, H.; Parker, J. V.; Scudder, D. W.; Shlachter, J. S.

    Pegasus II is the upgraded version of Pegasus, a pulsed power machine used in the Los Alamos AGEX (Above Ground Experiments) program. A goal of the program is to produce an intense (greater than 100 TW) source of soft x-rays from the thermalization of the kinetic energy of a 1 to 10 MJ plasma implosion. The radiation pulse should have a maximum duration of several 10's of nanoseconds and will be used in the study of fusion conditions and material properties. The radiating plasma source will be generated by the thermalization of the kinetic energy of an imploding cylindrical, thin, metallic foil. This paper addresses experiments done on a capacitor bank to develop a switch (plasma flow switch) to switch the bank current into the load at peak current. This allows efficient coupling of bank energy into foil kinetic energy.

  11. Results from the SLAC High Energy Density Plasma Lens Experiment

    NASA Astrophysics Data System (ADS)

    Ng, Johnny S. T.

    2000-04-01

    The plasma lens was proposed(P. Chen, Part. Acc. 20), 171 (1987). as a final focusing mechanism to achieve high luminosity for future high energy linear colliders. Previous experiments(See, for example, R. Govil et al.), Phys. Rev. Lett, 86, No. 16, 3202 (1999), and references therein. to test this concept were carried out at low energy densities. In this talk, results from the SLAC E-150 experiment(P. Chen et al.), Proposal for a Plasma Lens Experiment at the Final Focus Test Beam, SLAC Expt. Prop. E-150, April 1997. on plasma lens focusing of a high energy density beam with parameters relevant to linear colliders are presented and compared with theoretical expectations. The experiment was carried out at the SLAC Final Focus Test Beam, with nominal parameters of 30 GeV beam energy, 1.5× 10^10 electrons per bunch, bunch length σz = 0.7 mm and beam cross-section σ_x^* × σ_y^* = 7 μm × 3 μm. The plasma lens was produced by a fast pulsing gas-jet providing a neutral Nitrogen gas column with density up to 5× 10^18 / cm^3. The gas was then ionized by the leading portion of the incident high energy density electron beam, while the rest of the electrons in the same bunch were focused by the strong plasma pinching force and a reduction in the beam size of up to 40% was measured. The beam waist was also measured and compared with detailed numerical calculations with a particles-in-cell code. The reduction in focal length indicated a focusing strength approximately 100 times that of the FFTB final focus magnets. The synchrotron radiation with critical energy in the 1-10 MeV range due to the strong bending of beam particles inside the plasma lens was observed for the first time.

  12. Web life: The Internet Plasma Physics Education Experience

    NASA Astrophysics Data System (ADS)

    2009-02-01

    An educational outreach site maintained by the Princeton Plasma Physics Laboratory in the US, IPPEX features several interactive, game-like tools (applets) for exploring the physics of fusion, the doughnut-shaped "tokamak" reactors used in fusion experiments around the world, and related topics.

  13. Rocket exhaust effects as active space plasma experiments of opportunity

    NASA Astrophysics Data System (ADS)

    Mendillo, M.

    1983-07-01

    Examples of how photometer and wide-angle airglow imaging systems can be used to study diffusive and photochemical properties of the upper atmosphere are given. Incoherent scatter measurements of a large-scale ionospheric hole are shown to yield estimates of dynamical and chemical rate constants associated with the plasma perturbations themselsves. The Spacelab-2 series of shuttle engine burn experiments are summarized.

  14. First Laser-Plasma Interaction and Hohlraum Experiments on NIF

    SciTech Connect

    Dewald, E L; Glenzer, S H; Landen, O L; Suter, L J; Jones, O S; Schein, J; Froula, D; Divol, L; Campbell, K; Schneider, M S; McDonald, J W; Niemann, C; Mackinnon, A J

    2005-06-17

    Recently the first hohlraum experiments have been performed at the National Ignition Facility (NIF) in support of indirect drive Inertial Confinement Fusion (ICF) designs. The effects of laser beam smoothing by spectral dispersion (SSD) and polarization smoothing (PS) on the beam propagation in long scale gas-filled pipes has been studied at plasma scales as found in indirect drive gas filled ignition hohlraum designs. The long scale gas-filled target experiments have shown propagation over 7 mm of dense plasma without filamentation and beam break up when using full laser smoothing. Vacuum hohlraums have been irradiated with laser powers up to 6 TW, 1-9 ns pulse lengths and energies up to 17 kJ to activate several diagnostics, to study the hohlraum radiation temperature scaling with the laser power and hohlraum size, and to make contact with hohlraum experiments performed at the NOVA and Omega laser facilities. Subsequently, novel long laser pulse hohlraum experiments have tested models of hohlraum plasma filling and long pulse hohlraum radiation production. The validity of the plasma filling assessment in analytical models and in LASNEX calculations has been proven for the first time. The comparison of these results with modeling will be discussed.

  15. Plasma Jet Experiments Using LULI 2000 Laser Facility

    NASA Astrophysics Data System (ADS)

    Loupias, B.; Falize, E.; Koenig, M.; Bouquet, S.; Ozaki, N.; Benuzzi-Mounaix, A.; Michaut, C.; Goahec, M. Rabec Le; Nazarov, W.; Courtois, C.; Aglitskiy, Y.; Faenov, A. Ya.; Pikuz, T.

    2007-01-01

    We present experiments performed with the LULI2000 nanosecond laser facility. We generated plasma jets by using specific designed target. The main measured quantities related to the jet such as its propagation velocity, temperature and emissive radius evolution are presented. We also performed analytical work, which explains the jet evolution in some cases.

  16. Experiments on beam plasma interactions and EM waves in magnetized plasmas

    NASA Astrophysics Data System (ADS)

    Phelps, Alan D. R.

    2012-04-01

    An energetic electron beam can exhibit several types of interesting behaviour when interacting with plasmas and/or magnetic fields. The focus in the present work is on electron cyclotron maser interactions. The instabilities that occur are also often observed in space as well as in the laboratory. Some of the high power sources of electromagnetic radiation, such as gyrodevices, make use of similar instability mechanisms. Laboratory experiments and numerical simulations have led to both a better understanding of natural phenomena and the development of high power electromagnetic radiation sources for several applications in fusion plasma physics. The gyrotron is one such device that is being used to provide auxiliary heating for large tokamaks via electron cyclotron resonance heating (ECRH). It is planned to use a number of gyrotrons supplied by several nations in the ITER experiment. In the ITER experiment these gyrotrons will not only be used for auxiliary heating but also for advanced tailoring of the tokamak plasma properties.

  17. Proceedings of the 1st Puerto Rico Biobanking Workshop

    PubMed Central

    Mora, Edna; Robb, James A.; Stefanoff, Gustavo; Mellado, Robert Hunter; Coppola, Domenico; Muñoz-Antonia, Teresita; Flores, Idhaliz

    2015-01-01

    The 1st Puerto Rico Biobanking Workshop took place on August 20th, 2014 in the Auditorium of the Comprehensive Cancer Center of the University of Puerto Rico, Medical Sciences Campus in San Juan Puerto Rico. The program for this 1-day, live workshop included lectures by three biobanking experts, followed by presentations from existing biobanks in Puerto Rico and audience discussion. The need for increasing biobanking expertise in Puerto Rico stems from the fact that Hispanics in general are underrepresented in the biobanks in existence in the US, which limits the research conducted specifically to understand the molecular differences in cancer cells compared to other better studied populations. In turn, this lack of information impairs the development of better diagnostic and therapeutic approaches for our population. Dr. James Robb, M.D., F.C.A.P., consulting pathologist to the National Cancer Institute (NCI) and the Office of Biorepositories and Biospecimen Research (OBBR), opened the workshop with a discussion on the basic aspects of the science of biobanking (e.g., what is a biobank; its goals and objectives; protocols and procedures) in his talk addressing the importance of banking tissues for advancing biomedical research. Next, Dr. Gustavo Stefanoff, from the Cancer Institutes Network of Latin America (RINC by its name in Spanish), explained the mission, objectives, and structure of the Network of Latin-American and Caribbean Biobanks (REBLAC by its name in Spanish), which despite limited resources and many challenges, currently accrue high quality human tissue specimens and data to support cancer research in the region. Dr. Robert Hunter-Mellado, Professor of Internal Medicine, Universidad Central del Caribe, followed with an examination of the ethical and regulatory aspects of biobanking tissues for future research, including informed consent of subjects; protection of human subjects rights; and balancing risks and benefit ratios. In the afternoon, the

  18. High-harmonic Fast Wave Heating and Current Drive Results for Deuterium H-mode Plasmas in the National Spherical Torus Experiment

    SciTech Connect

    G. Taylor, P.T. Bonoli, R.W. Harvey, J.C. hosea, E.F. Jaeger, B.P. LeBlanc, C.K. Phillisp, P.M. Ryan, E.J. Valeo, J.R. Wilson, J.C. Wright, and the NSTX Team

    2012-07-25

    A critical research goal for the spherical torus (ST) program is to initiate, ramp-up, and sustain a discharge without using the central solenoid. Simulations of non-solenoidal plasma scenarios in the National Spherical Torus Experiment (NSTX) [1] predict that high-harmonic fast wave (HHFW) heating and current drive (CD) [2] can play an important roll in enabling fully non-inductive (fNI {approx} 1) ST operation. The NSTX fNI {approx} 1 strategy requires 5-6 MW of HHFW power (PRF) to be coupled into a non-inductively generated discharge [3] with a plasma current, Ip {approx} 250-350 kA, driving the plasma into an HHFW H-mode with Ip {approx} 500 kA, a level where 90 keV deuterium neutral beam injection (NBI) can heat the plasma and provide additional CD. The initial approach on NSTX has been to heat Ip {approx} 300 kA, inductively heated, deuterium plasmas with CD phased HHFW power [2], in order to drive the plasma into an H-mode with fNI {approx} 1.

  19. Development of a plasma driven permeation experiment for TPE

    DOE PAGES

    Buchenauer, Dean; Kolasinski, Robert; Shimada, Masa; Donovan, David; Youchison, Dennis; Merrill, Brad

    2014-04-18

    Experiments on retention of hydrogen isotopes (including tritium) at temperatures less than 800 ?C have been carried out in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory [1,2]. To provide a direct measurement of plasma driven permeation in plasma facing materials at temperatures reaching 1000 ?C, a new TPE membrane holder has been built to hold test specimens (=1 mm in thickness) at high temperature while measuring tritium permeating through the membrane from the plasma facing side. This measurement is accomplished by employing a carrier gas that transports the permeating tritium from the backside of the membrane to ionmore » chambers giving a direct measurement of the plasma driven tritium permeation rate. Isolation of the membrane cooling and sweep gases from TPE’s vacuum chamber has been demonstrated by sealing tests performed up to 1000 ?C of a membrane holder design that provides easy change out of membrane specimens between tests. Simulations of the helium carrier gas which transports tritium to the ion chamber indicate a very small pressure drop (~700 Pa) with good flow uniformity (at 1000 sccm). Thermal transport simulations indicate that temperatures up to 1000 ?C are expected at the highest TPE fluxes.« less

  20. Development of a plasma driven permeation experiment for TPE

    SciTech Connect

    Buchenauer, Dean; Kolasinski, Robert; Shimada, Masa; Donovan, David; Youchison, Dennis; Merrill, Brad

    2014-04-18

    Experiments on retention of hydrogen isotopes (including tritium) at temperatures less than 800 ?C have been carried out in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory [1,2]. To provide a direct measurement of plasma driven permeation in plasma facing materials at temperatures reaching 1000 ?C, a new TPE membrane holder has been built to hold test specimens (=1 mm in thickness) at high temperature while measuring tritium permeating through the membrane from the plasma facing side. This measurement is accomplished by employing a carrier gas that transports the permeating tritium from the backside of the membrane to ion chambers giving a direct measurement of the plasma driven tritium permeation rate. Isolation of the membrane cooling and sweep gases from TPE’s vacuum chamber has been demonstrated by sealing tests performed up to 1000 ?C of a membrane holder design that provides easy change out of membrane specimens between tests. Simulations of the helium carrier gas which transports tritium to the ion chamber indicate a very small pressure drop (~700 Pa) with good flow uniformity (at 1000 sccm). Thermal transport simulations indicate that temperatures up to 1000 ?C are expected at the highest TPE fluxes.

  1. Hydrodynamic Modeling of the Plasma Liner Experiment (PLX)

    NASA Astrophysics Data System (ADS)

    Cassibry, Jason; Hsu, Scott; Witherspoon, Doug; Gilmore, Marc

    2009-11-01

    Implosions of plasma liners in cylindrically or spherically convergent geometries can produce high pressures and temperatures with a confinement or dwell time of the order of the rarefaction timescale of the liner. The Plasma Liner Experiment (PLX), to be built at LANL, will explore and demonstrate the feasibility of forming imploding plasma liners with the spherical convergence of hypersonic plasma jets. Modeling will be performed using SPHC and MACH2. According to preliminary 3D SPHC results, high Z plasma liners imploding on vacuum with ˜1.5MJ of initial stored energy will reach ˜100kbar, which is a main objective of the experimental program. Among the objectives of the theoretical PLX effort are to assist in the diagnostic analysis of the PLX, identify possible deleterious effects due to instabilities or asymmetries, identify departures from ideal behavior due to thermal and radiative transport, and help determine scaling laws for possible follow-on applications of ˜1 Mbar HEDP plasmas and magneto-inertial fusion. An overview of the plan to accomplish these objectives will be presented, and preliminary results will be summarized.

  2. Theory and Modeling of the Plasma Liner Experiment (PLX)

    NASA Astrophysics Data System (ADS)

    Cassibry, J. T.; Stanic, M. D.; Awe, T. J.; Hanna, D. S.; Davis, J. S.; Hsu, S. C.; Witherspoon, F. D.

    2010-11-01

    High pressures and temperatures may be generated at the center an imploding plasma liner. These phenomena are being studied on the Plasma Liner Experiment (PLX) in which a spherical liner is formed via the merging of plasma jets. The basic physical processes include pulsed plasma acceleration, plasma jet propagation in a vacuum, plasma jet merging, liner formation, liner implosion, stagnation, and rarefaction. Each of these processes is dominated by different physics, requiring different models. For example, λei at the jet merging radius may be ˜1 cm, so that liner formation is partially collisionless, while liner implosion is collision dominated. Further, the liner transitions from optically thin to gray during the implosion. An overview of the theory and modeling plan in support of PLX will be given, which includes 1D rad-hydro, 3D hydro, 3D MHD, 2D PIC, and 2D hybrid codes. We will emphasize our recent 3D hydro modeling, which provides insights into liner formation, implosion, and effects of initial jet parameters on scaling of peak pressure.

  3. Solar array experiments on the SPHINX satellite. [Space Plasma High voltage INteraction eXperiment satellite

    NASA Technical Reports Server (NTRS)

    Stevens, N. J.

    1974-01-01

    The Space Plasma, High Voltage Interaction Experiment (SPHINX) is the name given to an auxiliary payload satellite scheduled to be launched in January 1974. The principal experiments carried on this satellite are specifically designed to obtain the engineering data on the interaction of high voltage systems with the space plasma. The classes of experiments are solar array segments, insulators, insulators with pin holes and conductors. The satellite is also carrying experiments to obtain flight data on three new solar array configurations: the edge illuminated-multijunction cells, the teflon encased cells, and the violet cells.

  4. Progress in Development of Low Pressure High Density Plasmas on a Small Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    James, Royce; Lopez, M.; Nolan, S.; Page, E. L.; Schlank, C.; Sherman, J.; Stutzman, B. S.; Zuniga, J.

    2012-10-01

    At the Coast Guard Academy Plasma Lab (CGAPL), a small Helicon Plasma Experiment (HPX) is being developed to utilize the reputed high densities (10^13 cm-3 and higher) at low pressure (.01 T) [1], for eventual high temperature and density diagnostic development in future laboratory investigations. HPX is designed to create repeatedly stable plasmas induced by an RF frequency in the 10 to 70 MHz range and employs an electromagnet to provide the external energy in the plasma's magnetic field to transition from the H-Mode to the Helicon Mode. An acceleration coil, currently under construction, will place the plasma in the vacuum chamber for optical and particle probing. With the initial construction phase complete and first plasmas attained, HPX is constructing triple and mach particle probes, magnetic probes, and a single point 300 W Thompson Scattering system backed by a 32-channel DAQ system capable 12 bits of sampling precision at 2 MS/s for plasma property investigations. Progress on the development of the RF coupling system, magnetic coils, and qualitative observations from the optical and electric diagnostics are to be reported. [4pt] [1] K. Toki, et al., Thin Solid Films 506-507 (2005).

  5. Enhancement of the radiation yield in plasma flow switch experiments

    SciTech Connect

    Buff, J. ); Peterkin, R.E. Jr.; Roderick, N.F. ); Degnan, J.H. ); Frese, M.H. ); Turchi, P.J. . Dept. of Aeronautical and Astronautical Engineering)

    1991-06-01

    This paper reports that in a series of experiments that was performed at the Phillips Laboratory (Kirtland Air Force Base, New Mexico), the Shiva Star fast capacitor bank, an inductive store, and a plasma flow switch were used together to deliver multimega-ampere currents with submicrosecond rise times to cylindrical foil loads. Based on two-dimensional MHD simulations with the MACH2 code, the authors previously suggested design modifications to the switch that, when implemented in experiments, substantially increased the fraction of available current that was delivered to the load. The authors have performed a new series of numerical simulations of the plasma flow switch/imploding load system with the goal of discovering a way to boost the total power radiated by the imploding plasmas as it stagnates on the axis of symmetry. The changes to the experimental design that were investigated and which are discussed in this paper include variations of: The shape of the electrodes, size, and mass of the load foil, structure of the axial view vanes, shape and mass of the switching plasma, material from which the load is constructed, the degree to which the load is bowed, and the energy of the capacitor bank. Radiation yields in the range 6-9 TW are predicted for future experiments on Shiva Star.

  6. Laying a Foundation for Lifelong Learning: Case Studies of E-Assessment in Large 1st-Year Classes

    ERIC Educational Resources Information Center

    Nicol, David

    2007-01-01

    Concerns about noncompletion and the quality of the 1st-year student experience have been linked to recent changes in higher education such as modularisation, increased class sizes, greater diversity in the student intake and reduced resources. Improving formative assessment and feedback processes is seen as one way of addressing academic failure,…

  7. Formation of Plasma Targets Suitable for Equation of State Experiments.

    NASA Astrophysics Data System (ADS)

    Benage, John

    2005-10-01

    The measurement of the Equation of State (EOS) of materials in the dense-plasma state is difficult. The standard method for measuring EOS relies on the shock driven Hugoniot technique, where the material is initially at standard temperature and pressure and is shocked using a flyer plate. The locus of states produced using this technique is called the standard Hugoniot. However, the states produced do not fall into the regime of dense plasmas, where the EOS of the material is quite uncertain. We are developing a technique for measuring the EOS in a dense plasma, conditions far away from the standard Hugoniot. This technique requires that the initial condition of the material be at densities well below and temperatures well above standard. We have completed initial experiments producing and characterizing the plasma targets, a CH foam that has been heated to 1 eV using gold m-band x-rays created with the Trident laser. The measurements include visible spectroscopy and imaging along with x-ray radiography of this plasma target. Simulations of these initial measurements and of the laser drive necessary to produce a uniform shock in the material are also shown. The conditions that we calculate to be produced by this shock are then compared to models for the EOS of this material.

  8. Characterization of Dense Plasma Targets for Equation of State Experiments.

    NASA Astrophysics Data System (ADS)

    Hurry, Tom; Benage, John; Cobble, Jim; Dodd, Evan; Herrmann, Hans; Ortiz, Tom; Workman, Jonathan

    2006-10-01

    The measurement of the Equation of State (EOS) of materials in the dense-plasma state is difficult. The standard method for measuring EOS relies on the shock driven Hugoniot technique, where the material is initially at standard temperature and pressure and is shocked using a flyer plate. The locus of states produced using this technique is called the standard Hugoniot. However, the states produced do not fall into the regime of dense plasmas, where the EOS of the material is quite uncertain. We are developing a technique for measuring the EOS in a dense plasma, conditions far away from the standard Hugoniot. This technique requires that the initial condition of the material be at densities well below and temperatures well above standard. We have completed initial experiments producing and characterizing the plasma targets using visible spectroscopy and imaging. We have also begun development of a dynamic phase contrast imaging system required for measuring the shock velocity in the plasma. Simulations of these initial measurements and of the laser drive necessary to produce a uniform shock in the material are also shown. The conditions that we calculate to be produced by this shock are then compared to models for the EOS of this material.

  9. Overview, Status, and Plans of the Plasma Liner Experiment (PLX)

    NASA Astrophysics Data System (ADS)

    Hsu, S. C.; Awe, T. J.; Hanna, D. S.; Davis, J. S.; Witherspoon, F. D.; Cassibry, J. T.; Gilmore, M. A.; Hwang, D. Q.

    2010-11-01

    The Plasma Liner Experiment (PLX) is a multi-institutional collaboration that is exploring and demonstrating the feasibility of forming imploding spherical plasma liners to reach peak pressures ˜0.1 Mbar upon stagnation. The liners will be formed via merging of 30--60 dense high Mach number plasma jets (n˜10^17 cm-3, M˜10--35, v˜50--70 km/s, rjet˜5 cm) in spherically convergent geometry. We are aiming for two potential follow-on applications if this work is successful: (1) assembling repetitive, macroscopic (cm and μs scale) plasmas suitable for fundamental HEDLP scientific studies and (2) a standoff driver solution for magneto-inertial fusion. This is a staged project where scientific issues will be studied first at modest stored energies (˜300 kJ) before attempting to reach HED-relevant pressures (requiring ˜1.5 MJ)@. This poster provides an overview/status of the project and the research plan, which includes numerical/theoretical and experimental studies of plasma jet formation/acceleration, propagation/merging, liner convergence/stagnation, and laser driven beat waves for magnetizing the imploding liner.

  10. Exploring space plasmas - The WISP/HF experiment

    SciTech Connect

    James, H.G.; Darlington, T.R.; Hersom, C.H.; Gruno, R.S.; Gore, J.V.

    1987-02-01

    WISP/HF is the high-frequency part of the collaborative U.S.-Canada investigation, Waves in Space Plasmas. Instrumentation is being developed that will be flown on NASA's Space Shuttle starting with the Space Plasma Lab missions in the 1990s. Using a high-inclination orbit at heights near the maximum density of the ionospheric F region, active experiments will be carried out on antennas, electromagnetic and electrostatic wave propagation, problems in linear and nonlinear plasma physics, large-scale ionospheric structures, ionospheric irregularities, and the interaction of charged-particle beams with the ionospheric plasma. The WISP/HF equipment will generate, receive, and process signals in the 0.1-to 30-MHz range. The Orbiter-based transmitter will have variable pulse-power levels up to 0.5 kW and will use a dipole of variable length up to 300 m tip-to-tip. WISP/HF receivers will be located both on the Orbiter and on a subsatellite. A high level of operational flexibility in the WISP/HF instrument design has been achieved through programmable digital control. The design also permits human control of experiments, both from the Orbiter and from the ground.

  11. Experiments on Initial Formation of Plasma Flow Switches.

    NASA Astrophysics Data System (ADS)

    Benage, John F., Jr.; Bowers, Richard; Oona, Hank; Wysocki, Fred; Broste, William B.; Harper, Ron; Roderick, Norm

    1996-11-01

    Plasma flow switches have been used to shorten the current pulse for inductive storage capacitor banks to implode plasmas for producing radiation.(J.H.Degnan, et.al., IEEE Trans. Plasma Sci., PS-15, 760(1987).)They consist of two components, an aluminum wire array and a plastic barrier film separated by a few mm. We have performed a series of experiments at Los Alamos to understand the sensitivity of the performance of plasma flow switches to their initial conditions. These experiments were done on two facilities, one a 250 kJ capacitor bank called the Colt facility with a maximum current of 1.0 MA in 2.5 microseconds. The other is the Pegasus II facility with a maximum current of 10 MA in a time of 4 microseconds. The overall performance of the switch as determined by the voltage developed was measured as a function of the mass of the switch, the distribution of the mass among the switch components, and the separation of the components. A preliminary understanding of the important parameters and the physical basis for their importance will be given. (This worked performed under the auspices of the Department of Energy.)

  12. Progress on Development of Low Pressure High Density Plasmas on the Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    James, Royce; Azzari, Phillip; Duke-Tinson, Omar; Frank, John; Karama, Jackson; Hopson, Jordan; Paolino, Richard; Sandri, Eva; Sherman, Justin; Wright, Erin; Turk, Jeremy

    2015-11-01

    The small Helicon Plasma Experiment (HPX) at the Coast Guard Academy Plasma Lab (CGAPL), continues to progress toward utilizing the reputed high densities (1013 cm-3 and higher) at low pressure (.01 T) [1] of helicons, for eventual high temperature and density diagnostic development in future laboratory investigations. HPX is designed to create repeatedly stable plasmas (~ 20 - 30 ns) induced by an RF frequency in the 10 to 70 MHz range. HPX is constructing RF field corrected Langmuir probe raw data will be collected and used to measure the plasma's density, temperature, and potentially the structure and behavior during experiments. Our 2.5 J YAG laser Thomson Scattering system backed by a 32-channel Data Acquisition (DAQ) system is capable 12 bits of sampling precision at 2 MS/s for HPX plasma property investigations. Progress on the development of the RF coupling system, Helicon Mode development, magnetic coils, and observations from the Thomson Scattering, particle, and electromagnetic scattering diagnostics will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY15.

  13. Progress on Development of Low Pressure High Density Plasmas on the Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    James, R. W.; Duke-Tinson, O.; Nolan, S.; Page, E. J.; Lopez, M.; Karama, J.; Paolino, R. N.; Schlank, C.; Sherman, J.; Stutzman, B. S.; Crilly, P. B.

    2013-10-01

    At the Coast Guard Academy Plasma Lab (CGAPL), a small Helicon Plasma Experiment (HPX) is being developed to utilize the reputed high densities (1013 cm-3 and higher) at low pressure (.01 T), for eventual high temperature and density diagnostic development in future laboratory investigations. HPX is designed to create repeatedly stable plasmas induced by an RF frequency in the 10 to 70 MHz range. We employ a 400 to 1000 Gauss electromagnet that promotes energy conservation in the plasma via external energy production in the magnetic field facilitated by decreased inertial effects, in order to reach the Helicon Mode. With the initial construction phase complete and repeatable plasmas attained, HPX is constructing triple and mach particle probes, magnetic probes, and a single point 300 W Thompson Scattering system backed by a 32-channel Data Acquisition (DAQ) system capable 12 bits of sampling precision at 2 MS/s for HPX plasma property investigations. Progress on the development of the RF coupling system, Helicon Mode development, magnetic coils, and observations from the optical, particle, and electromagnetic scattering diagnostics will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY12.

  14. Confinement projections for the Burning Plasma Experiment (BPX)

    SciTech Connect

    Goldston, R.J.; Bateman, G.; Kaye, S.M.; Perkins, F.W.; Pomphrey, N.; Stotler, D.P.; Zarnstorff, M.C. . Plasma Physics Lab.); Houlberg, W.A.; Neilson, G.H. ); Porkolab, M. ); Reidel, K.S. ); Stambaugh, R.D.; Waltz, R.E. )

    1991-01-01

    The mission of the Burning Plasma Experiment (BPX, formerly CIT) is to study the physics of self-heated fusion plasmas (Q = 5 to ignition), and to demonstrate the production of substantial amounts of fusion power (P{sub fus} = 100 to 500 MW). Confinement projections for BPX have been made on the basis of (1) dimensional extrapolation (2) theory-based modeling calibrated to experiment, and (3) statistical scaling from the available empirical data base. The results of all three approaches, discussed in this paper, roughly coincide. We presently view the third approach, statistical scaling, as the most reliable means for projecting the confinement performance of BPX, and especially for assessing the uncertainty in the projection. 11 refs., 2 figs., 1 tab.

  15. Experiments of new plasma concepts for enhanced microwave vacuum electronics

    SciTech Connect

    Muggli, P.; Hoffman, J.R.; Yampolsky, J.; Cordell, J.F.; Gundersen, M.A.; Joshi, C.; Katsouleas, T.

    1999-07-01

    Recently new schemes have been proposed for plasma based microwave sources that could lead to output power increases by orders of magnitude, as well as offer new possibilities such as broad band tuning and frequency chirping, ultra-short pulse generation, pulse design, etc. In the first scheme, the static field of an alternatively biased capacitor is directly converted into short pulses of turnable electromagnetic (em) radiation upon transmission through a relativistic; under dense ionization front. The structure presently under investigation consists of pin pairs (capacitors) inserted into an X-band waveguide through its narrow sidewall and separated by 1.134 cm. The generated frequency is in the X-band frequency range (8.4--12.4 GHz) when operated with plasma densities between 10{sup 11} and 10{sup 12} cm{sup {minus}3}. The output power is in the 100 W range with an applied voltage of 6 kV and is limited by high voltage (HV) breakdown inside the structure. Much higher output power levels are expected with the new, shorter pulse, HV pulser, since the output power is proportional to the square of the applied voltage. At larger plasma densities, generation of a higher order mode traveling in the backward direction is also observed. In the second scheme, a fraction of the large amplitude electrostatic (es) wave generated in a plasma beat wave acceleration (PBWA) experiment (up to 3 GeV/m) is converted into em radiation by applying a static magnetic field perpendicularly to the driving laser beam. The two-frequency CO{sub 2} laser beam resonantly drives the es wave, and couples to the L branch of the XO mode of the magnetized plasma through Cherenkov radiation. The radiation is emitted predominantly in the forward direction (direction of the laser beam), and is at the plasma frequency (n{sub c} {approximately}10{sup 16} cm{sup {minus}3}, f{approximately}1 THz). With an applied magnetic field of 6 kG the output power is calculated to be in the megawatt range (for a

  16. Radiative Shocks And Plasma Jets As Laboratory Astrophysics Experiments

    SciTech Connect

    Koenig, M.; Loupias, B.; Vinci, T.; Ozaki, N.; Benuzzi-Mounaix, A.; Rabec le Goahec, M.; Falize, E.; Bouquet, S.; Courtois, C.; Nazarov, W.; Aglitskiy, Y.; Faenov, A. Ya.; Pikuz, T.; Schiavi, A.

    2007-08-02

    Dedicated laboratory astrophysics experiments have been developed at LULI in the last few years. First, a high velocity (70 km/s) radiative shock has been generated in a xenon filled gas cell. We observed a clear radiative precursor, measure the shock temperature time evolution in the xenon. Results show the importance of 2D radiative losses. Second, we developed specific targets designs in order to generate high Mach number plasma jets. The two schemes tested are presented and discussed.

  17. Radiative Shocks And Plasma Jets As Laboratory Astrophysics Experiments

    NASA Astrophysics Data System (ADS)

    Koenig, M.; Loupias, B.; Vinci, T.; Ozaki, N.; Benuzzi-Mounaix, A.; Rabec Le Goahec, M.; Falize, E.; Bouquet, S.; Michaut, C.; Herpe, G.; Baroso, P.; Nazarov, W.; Aglitskiy, Y.; Faenov, A. Ya.; Pikuz, T.; Courtois, C.; Woolsey, N. C.; Gregory, C. D.; Howe, J.; Schiavi, A.; Atzeni, S.

    2007-08-01

    Dedicated laboratory astrophysics experiments have been developed at LULI in the last few years. First, a high velocity (70 km/s) radiative shock has been generated in a xenon filled gas cell. We observed a clear radiative precursor, measure the shock temperature time evolution in the xenon. Results show the importance of 2D radiative losses. Second, we developed specific targets designs in order to generate high Mach number plasma jets. The two schemes tested are presented and discussed.

  18. Plasma Simulation for the SHIP Experiment at GDT

    SciTech Connect

    Anikeev, A.V.; Bagryansky, P.A.; Collatz, S.; Noack, K

    2005-01-15

    The concept of the Synthesized Hot Ion Plasmoid (SHIP) experiment at the gas dynamic trap (GDT) facility of the Budker Institute Novosibirsk was presented at the 29{sup th} EPS Conference. During the last year several numerical simulations were made by means of the Integrated Transport Code System (ITCS) to determine the best experimental scenario for getting high plasma parameters. This contribution presents important results of the recent numerical simulations of SHIP by means of the ITCS modules.

  19. The Tordo 1 polar cusp barium plasma injection experiment

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.; Stenbaek-Nielsen, H. C.; Davis, T. N.; Jeffries, R. A.; Roach, W. H.

    1978-01-01

    In January 1975, two barium plasma injection experiments were carried out with rockets launched into the upper atmosphere where field lines from the dayside cusp region intersect the ionosphere. The Tordo 1 experiment took place near the beginning of a worldwide magnetic storm. It became a polar cap experiment almost immediately as convection perpendicular to the magnetic field moved the fluorescent plasma jet away from the cusp across the polar cap in an antisunward direction. Convection across the polar cap with an average velocity of more than 1 km/s was observed for nearly 40 min until the barium flux tubes encountered large electron fields associated with a poleward bulge of the auroral oval near Greenland. Prior to the encounter with the aurora near Greenland there is evidence of upward acceleration of the barium ions while they were in the polar cap. The three-dimensional observations of the plasma orientation and motion give an insight into convection from the cusp region across the polar cap, the orientation of the polar cap magnetic field lines out to several earth radii, the causes of polar cap magnetic perturbations, and parallel acceleration processes.

  20. ["1st Therapeutic Red Cross Hospital" during the civil war].

    PubMed

    Simonenko, V B; Abashin, V G

    2014-04-01

    The article presents the documentary information about the founding, the establishment and early years of the 1st Therapeutic Red Cross Hospital - in the future - Mandryka Central Military Clinical Hospital of the Ministry of Defence of the Russian Federation. Presented the work of the Hospital during the dificult period of the Civil War, typhus epidemic, famine and devastation. Specified its staffing structure, command, medical and administrative staff, travel and accommodation till the moment of the deployment in the Silver Lane in Moscow. PMID:25051792

  1. The 1st All-Russian Workshop on Archaeoastronomy

    NASA Astrophysics Data System (ADS)

    Bochkarev, Nikolai G.

    2007-08-01

    The 1st All-Russia Workshop on Archaeoastronomy “Astronomical and World-Outlook Meaning of the Archaeological Monuments of South Ural” was held on June 19-25, 2006, at the ground of the archaeological center “Arkaim” (Chelyabinsk Region). Besides about 30 talks, astronomical measurements were performed at two archaeological objects under intensive study: Arkaim Site (Bronze Epoch, XVIII-XVI c. B.C.) and tumuli “with whiskers” complex Kondurovsky (V-VIII c. A.D.). The promising character of the megalithic complex on the Vera Island (Lake Turgoyak) was stated.

  2. Supersonic gas jets for laser-plasma experiments.

    PubMed

    Schmid, K; Veisz, L

    2012-05-01

    We present an in-depth analysis of De Laval nozzles, which are ideal for gas jet generation in a wide variety of experiments. Scaling behavior of parameters especially relevant to laser-plasma experiments as jet collimation, sharpness of the jet edges and Mach number of the resulting jet is studied and several scaling laws are given. Special attention is paid to the problem of the generation of microscopic supersonic jets with diameters as small as 150 μm. In this regime, boundary layers dominate the flow formation and have to be included in the analysis.

  3. Modeling of Spherical Torus Plasmas for Liquid Lithium Wall Experiments

    SciTech Connect

    R. Kaita; S. Jardin; B. Jones; C. Kessel; R. Majeski; J. Spaleta; R. Woolley; L. Zakharo; B. Nelson; M. Ulrickson

    2002-01-29

    Liquid metal walls have the potential to solve first-wall problems for fusion reactors, such as heat load and erosion of dry walls, neutron damage and activation, and tritium inventory and breeding. In the near term, such walls can serve as the basis for schemes to stabilize magnetohydrodynamic (MHD) modes. Furthermore, the low recycling characteristics of lithium walls can be used for particle control. Liquid lithium experiments have already begun in the Current Drive eXperiment-Upgrade (CDX-U). Plasmas limited with a toroidally localized limiter have been investigated, and experiments with a fully toroidal lithium limiter are in progress. A liquid surface module (LSM) has been proposed for the National Spherical Torus Experiment (NSTX). In this larger ST, plasma currents are in excess of 1 MA and a typical discharge radius is about 68 cm. The primary motivation for the LSM is particle control, and options for mounting it on the horizontal midplane or in the divertor region are under consideration. A key consideration is the magnitude of the eddy currents at the location of a liquid lithium surface. During plasma start up and disruptions, the force due to such currents and the magnetic field can force a conducting liquid off of the surface behind it. The Tokamak Simulation Code (TSC) has been used to estimate the magnitude of this effect. This program is a two dimensional, time dependent, free boundary simulation code that solves the MHD equations for an axisymmetric toroidal plasma. From calculations that match actual ST equilibria, the eddy current densities can be determined at the locations of the liquid lithium. Initial results have shown that the effects could be significant, and ways of explicitly treating toroidally local structures are under investigation.

  4. Plasma mitigation of shock wave: experiments and theory

    NASA Astrophysics Data System (ADS)

    Kuo, Spencer P.

    2007-12-01

    Two types of plasma spikes, generated by on-board 60 Hz periodic and pulsed dc electric discharges in front of two slightly different wind tunnel models, were used to demonstrate the non-thermal plasma techniques for shock wave mitigation. The experiments were conducted in a Mach 2.5 wind tunnel. (1) In the periodic discharge case, the results show a transformation of the shock from a well-defined attached shock into a highly curved shock structure, which has increased shock angle and also appears in diffused form. As shown in a sequence with increasing discharge intensity, the shock in front of the model moves upstream to become detached with increasing standoff distance from the model and is eliminated near the peak of the discharge. The power measurements exclude the heating effect as a possible cause of the observed shock wave modification. A theory using a cone model as the shock wave generator is presented to explain the observed plasma effect on shock wave. The analysis shows that the plasma generated in front of the model can effectively deflect the incoming flow; such a flow deflection modifies the structure of the shock wave generated by the cone model, as shown by the numerical results, from a conic shape to a curved one. The shock front moves upstream with a larger shock angle, matching well with that observed in the experiment. (2) In the pulsed dc discharge case, hollow cone-shaped plasma that envelops the physical spike of a truncated cone model is produced in the discharge; consequently, the original bow shock is modified to a conical shock, equivalent to reinstating the model into a perfect cone and to increase the body aspect ratio by 70%. A significant wave drag reduction in each discharge is inferred from the pressure measurements; at the discharge maximum, the pressure on the frontal surface of the body decreases by more than 30%, the pressure on the cone surface increases by about 5%, whereas the pressure on the cylinder surface remains

  5. Experiments on Plasma Injection into a Centrifugally Confined System

    NASA Astrophysics Data System (ADS)

    Messer, S.; Bomgardner, R.; Brockington, S.; Case, A.; Witherspoon, F. D.; Uzun-Kaymak, I.; Elton, R.; Young, W.; Teodorescu, C.; Morales, C. H.; Ellis, R. F.

    2009-11-01

    We describe the cross-field injection of plasma into a centrifugally-confined system. Two different types of plasma railgun have been installed on the Maryland Centrifugal Experiment (MCX) in an attempt to drive that plasma's rotation. The initial gun was a coaxial device designed to mitigate the blowby instability. The second one was a MiniRailgun with a rectangular bore oriented so that the MCX magnetic field augments the railgun's internal magnetic field. Tests at HyperV indicate this MiniRailgun reaches much higher densities than the original gun, although muzzle velocity is slightly reduced. We discuss the impact of these guns on MCX for various conditions. Initial results show that even for a 2 kG field, firing the MiniRailgun modifies oscillations of the MCX diamagnetic loops and can impact the core current and voltage. The gun also has a noticeable impact on MCX microwave emissions. These observations suggest plasma enters the MCX system. We also compare diagnostic data collected separately from MCX for these and other guns, focussing primarily on magnetic measurements.

  6. Plasma density observations from the Dynamic Ionosphere Cubesat Experiment (DICE)

    NASA Astrophysics Data System (ADS)

    Barjatya, A.; Swenson, C.; Fish, C. S.; Crowley, G.; Pilinski, M.; Azeem, S. I.; Neilsen, T. L.

    2012-12-01

    The Dynamic Ionosphere Cubesat Experiment (DICE) was launched into an eccentric low Earth orbit on October 28, 2011 on a NASA rocket from Vandenburg Air Force Base. DICE consists of two identical 1.5U CubeSats with a mission objective to study and characterize geomagnetic Storm Enhanced Density (SED) bulge and plume by multipoint measurements. Each identical spacecraft carries two Langmuir probes to measure in-situ plasma densities, electric field probes to measure in-situ DC and AC electric fields, and a magnetometer to measure in-situ DC and AC magnetic fields. This work presents Langmuir probe data from both the CubeSats as they follow each other. The two Langmuir probes are deployed 180 degrees apart on 10cm long scissor booms from the top and bottom of the CubeSats. The probes are primarily operated in the ion saturation region as fixed bias probes to give relative plasma densities, but periodically swept (every 100 seconds) to give absolute plasma density and temperature. The derived densities will be compared to International Reference Ionosphere as well as other models.; Comparison of relative plasma density derived from two fixed bias Langmuir probes (DCP+ and DCP-) on DICE with IRI model.

  7. Summary of Plasma Liner Experiment (PLX) Research Results

    NASA Astrophysics Data System (ADS)

    Hsu, S. C.; Moser, A. L.; Davis, J. S.; Dunn, J. P.; Awe, T. J.; Merritt, E. C.; Adams, C. S.; Lynn, A. G.; Gilmore, M. A.; Brockington, S.; Case, A.; Messer, S. J.; van Doren, D.; Witherspoon, F. D.; Cassibry, J. T.; Stanic, M.

    2012-10-01

    Spherically imploding plasma liners could result in cm-, μs-, and Mbar-scale plasmas upon stagnation, which is of interest for fundamental high energy density (HED) plasma physics studies. They are also envisioned as a potential standoff compression driver for magneto-inertial fusion (MIF)@. Experiments on PLX over the past year have focused on characterizing the propagation of a single argon plasma jet and the oblique merging of two jets, and assessing the suitability of the jets for the HED and MIF applications. Via a multi-chord interferometer, survey spectrometer, photodiode array, and fast framing imaging camera, we are determining that the jets are near the PLX design goal with respect to density (10^17 cm-3) and velocity (50 km/s). The key physics issues being studied are the rate of jet expansion during propagation, and the potentially deleterious effects of jet merging such as shock formation and heating which could degrade imploding liner performance. This poster will provide a project summary, and a highlight of experimental results on both sin

  8. Experimental characterization of a coaxial plasma accelerator for a colliding plasma experiment

    SciTech Connect

    Wiechula, J.; Hock, C.; Iberler, M.; Manegold, T.; Schönlein, A.; Jacoby, J.

    2015-04-15

    We report experimental results of a single coaxial plasma accelerator in preparation for a colliding plasma experiment. The utilized device consisted of a coaxial pair of electrodes, accelerating the plasma due to J×B forces. A pulse forming network, composed of three capacitors connected in parallel, with a total capacitance of 27 μF was set up. A thyratron allowed to switch the maximum applied voltage of 9 kV. Under these conditions, the pulsed currents reached peak values of about 103 kA. The measurements were performed in a small vacuum chamber with a neutral-gas prefill at gas pressures between 10 Pa and 14 000 Pa. A gas mixture of ArH{sub 2} with 2.8% H{sub 2} served as the discharge medium. H{sub 2} was chosen in order to observe the broadening of the H{sub β} emission line and thus estimate the electron density. The electron density for a single plasma accelerator reached peak values on the order of 10{sup 16} cm{sup −3}. Electrical parameters, inter alia inductance and resistance, were determined for the LCR circuit during the plasma acceleration as well as in a short circuit case. Depending on the applied voltage, the inductance and resistance reached values ranging from 194 nH to 216 nH and 13 mΩ to 23 mΩ, respectively. Furthermore, the plasma velocity was measured using a fast CCD camera. Plasma velocities of 2 km/s up to 17 km/s were observed, the magnitude being highly correlated with gas pressure and applied voltage.

  9. Experimental characterization of a coaxial plasma accelerator for a colliding plasma experiment

    NASA Astrophysics Data System (ADS)

    Wiechula, J.; Hock, C.; Iberler, M.; Manegold, T.; Schönlein, A.; Jacoby, J.

    2015-04-01

    We report experimental results of a single coaxial plasma accelerator in preparation for a colliding plasma experiment. The utilized device consisted of a coaxial pair of electrodes, accelerating the plasma due to J ×B forces. A pulse forming network, composed of three capacitors connected in parallel, with a total capacitance of 27 μF was set up. A thyratron allowed to switch the maximum applied voltage of 9 kV. Under these conditions, the pulsed currents reached peak values of about 103 kA. The measurements were performed in a small vacuum chamber with a neutral-gas prefill at gas pressures between 10 Pa and 14 000 Pa. A gas mixture of ArH2 with 2.8% H2 served as the discharge medium. H2 was chosen in order to observe the broadening of the Hβ emission line and thus estimate the electron density. The electron density for a single plasma accelerator reached peak values on the order of 1016 cm-3 . Electrical parameters, inter alia inductance and resistance, were determined for the LCR circuit during the plasma acceleration as well as in a short circuit case. Depending on the applied voltage, the inductance and resistance reached values ranging from 194 nH to 216 nH and 13 mΩ to 23 mΩ, respectively. Furthermore, the plasma velocity was measured using a fast CCD camera. Plasma velocities of 2 km/s up to 17 km/s were observed, the magnitude being highly correlated with gas pressure and applied voltage.

  10. Development of Low Pressure High Density Plasmas on the Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    James, Royce; Azzari, Phillip; Crilly, Paul; Duke-Tinson, Omar; Karama, Jackson; Paolino, Richard; Schlank, Carter; Sherman, Justin

    2014-10-01

    The small Helicon Plasma Experiment (HPX) at the Coast Guard Academy Plasma Lab (CGAPL), continues to progress toward utilizing the reputed high densities (10 cm-3 and higher) at low pressure (.01 T) of helicons, for eventual high temperature and density diagnostic development in future laboratory investigations. HPX is designed to create repeatedly stable plasmas induced by an RF frequency in the 10 to 70 MHz range. We employ a 400 to 1000 Gauss electromagnet that promotes energy conservation in the plasma via external energy production in the magnetic field facilitated by decreased inertial effects, in order to reach the Helicon Mode. HPX is completing construction of triple and mach particle probes, magnetic probes, and is designing a single point 300 W Thompson Scattering system backed by a 32-channel Data Acquisition (DAQ) system capable 12 bits of sampling precision at 2 MS/s for HPX plasma property investigations. Progress on the development of the RF coupling system, Helicon Mode development, magnetic coils, and observations from the optical, particle, and electromagnetic scattering diagnostics will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY13.

  11. Design and Assembly of the Magnetized Dusty Plasma Experiment (MDPX)

    NASA Astrophysics Data System (ADS)

    Fisher, Ross; Artis, Darrick; Lynch, Brian; Wood, Keith; Shaw, Joseph; Gilmore, Kevin; Robinson, Daniel; Polka, Christian; Konopka, Uwe; Thomas, Edward; Merlino, Robert; Rosenberg, Marlene

    2013-10-01

    Over the last two years, the Magnetized Dusty Plasma Experiment (MDPX) has been under construction at Auburn University. This new research device, whose assembly will be completed in late Summer, 2013, uses a four-coil, superconducting, high magnetic field system (|B | >= 4 Tesla) to investigate the confinement, charging, transport, and instabilities in a dusty plasma. A new feature of the MDPX device is the ability to operate the magnetic coils independently to allow a variety of magnetic configurations from highly uniform to quadrapole-like. Envisioned as a multi-user facility, the MDPX device features a cylindrical vacuum vessel whose primary experimental region is an octagonal chamber that has a 35.5 cm inner diameter and is 19 cm tall. There is substantial diagnostics and optical access through eight, 10.2 cm × 12.7 cm side ports. The chamber can also be equipped with two 15.2 cm diameter, 76 cm long extensions to allow long plasma column experiments, particularly long wavelength dust wave studies. This presentation will discuss the final design, assembly, and installation of the MDPX device and will describe its supporting laboratory facility. This work is supported by a National Science Foundation - Major Research Instrumentation (NSF-MRI) award, PHY-1126067.

  12. The Skylab barium plasma injection experiments. I - Convection observations

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.; Stenbaek-Nielsen, H. C.; Davis, T. N.; Peek, H. M.

    1976-01-01

    Two barium-plasma injection experiments were carried out during magnetically active periods in conjunction with the Skylab 3 mission. The high-explosive shaped charges were launched near dawn on November 27 and December 4, 1973, UT. In both cases, the AE index was near 400 gammas, and extensive pulsating auroras covered the sky. The first experiment, Skylab Alpha, occurred in the waning phase of a 1000-gamma substorm, and the second, Skylab Beta, occurred in the expansive phase of an 800-gamma substorm. In both, the convection was generally magnetically eastward, with 100-km-level electric fields near 40 mV/m. However, in the Alpha experiment the observed orientation of the barium flux tube fit theoretical field lines having no parallel current, but the Beta flux-tube orientation indicated a substantial upward parallel sheet current.

  13. 1st Stage Separation Aerodynamics Of VEGA Launcher

    NASA Astrophysics Data System (ADS)

    Genito, M.; Paglia, F.; Mogavero, A.; Barbagallo, D.

    2011-05-01

    VEGA is an European launch vehicle under development by the Prime Contractor ELV S.p.A. in the frame of an ESA contract. It is constituted by four stages, dedicated to the scientific/commercial market of small satellites (300 ÷ 2500 kg) into Low Earth Orbits, with inclinations ranging from 5.2° up to Sun Synchronous Orbits and with altitude ranging from 300 to 1500 km. Aim of this paper is to present a study of flow field due to retro-rockets impingement during the 1st stage VEGA separation phase. In particular the main goal of the present work is to present the aerodynamic activities performed for the justification of the separation phase.

  14. The Madison plasma dynamo experiment: A facility for studying laboratory plasma astrophysics

    NASA Astrophysics Data System (ADS)

    Cooper, C. M.; Wallace, J.; Brookhart, M.; Clark, M.; Collins, C.; Ding, W. X.; Flanagan, K.; Khalzov, I.; Li, Y.; Milhone, J.; Nornberg, M.; Nonn, P.; Weisberg, D.; Whyte, D. G.; Zweibel, E.; Forest, C. B.

    2014-01-01

    The Madison plasma dynamo experiment (MPDX) is a novel, versatile, basic plasma research device designed to investigate flow driven magnetohydrodynamic instabilities and other high-β phenomena with astrophysically relevant parameters. A 3 m diameter vacuum vessel is lined with 36 rings of alternately oriented 4000 G samarium cobalt magnets, which create an axisymmetric multicusp that contains ˜14 m3 of nearly magnetic field free plasma that is well confined and highly ionized (>50%). At present, 8 lanthanum hexaboride (LaB6) cathodes and 10 molybdenum anodes are inserted into the vessel and biased up to 500 V, drawing 40 A each cathode, ionizing a low pressure Ar or He fill gas and heating it. Up to 100 kW of electron cyclotron heating power is planned for additional electron heating. The LaB6 cathodes are positioned in the magnetized edge to drive toroidal rotation through J × B torques that propagate into the unmagnetized core plasma. Dynamo studies on MPDX require a high magnetic Reynolds number Rm > 1000, and an adjustable fluid Reynolds number 10 < Re < 1000, in the regime where the kinetic energy of the flow exceeds the magnetic energy (MA2=(v/vA)2>1). Initial results from MPDX are presented along with a 0-dimensional power and particle balance model to predict the viscosity and resistivity to achieve dynamo action.

  15. OBSERVATIONS OF THERMAL FLARE PLASMA WITH THE EUV VARIABILITY EXPERIMENT

    SciTech Connect

    Warren, Harry P.; Doschek, George A.; Mariska, John T.

    2013-06-20

    One of the defining characteristics of a solar flare is the impulsive formation of very high temperature plasma. The properties of the thermal emission are not well understood, however, and the analysis of solar flare observations is often predicated on the assumption that the flare plasma is isothermal. The EUV Variability Experiment (EVE) on the Solar Dynamics Observatory provides spectrally resolved observations of emission lines that span a wide range of temperatures (e.g., Fe XV-Fe XXIV) and allow for thermal flare plasma to be studied in detail. In this paper we describe a method for computing the differential emission measure distribution in a flare using EVE observations and apply it to several representative events. We find that in all phases of the flare the differential emission measure distribution is broad. Comparisons of EVE spectra with calculations based on parameters derived from the Geostationary Operational Environmental Satellites soft X-ray fluxes indicate that the isothermal approximation is generally a poor representation of the thermal structure of a flare.

  16. Plasma Flow and Equilibrium Considerations in the STX Experiment

    NASA Astrophysics Data System (ADS)

    Miller, K. E.; Slough, J. T.

    2001-10-01

    The STX experiment was operated during the construction phase of TCS, primarily to investigate the ability of the Rotating Magnetic Field (RMF) to directly form an FRC, without the usual theta pinch technology. STX utilized a 25G RMF at 350kHz to form 2m long by 0.2m radius FRCs. Plasmas were typically fully ionized deuterium with a temperature of 60 eV and a peak density of 5x10^18m-3. Axial confining fields of 100G maintained a true vacuum boundary around the plasma and allowed for the study of FRC RMF equilibrium interactions. Key findings are that the RMF drove strong radial and axial flows, produced radial profiles markedly different from those of theta pinch formed FRCs, and resulted in enhanced particle and energy confinement. Although the FRCs were usually not sustained, they evolved into an interesting mirror like configuration that also exhibited enhanced particle and energy confinement. Issues discussed include the importance of the RMF driving an azimuthal current distribution consistent with that of the FRC, possible benefits of varying the average beta condition, and potential RMF antenna length limits set by the tendency of driven axial flows to screen the RMF from the plasma.

  17. Relaunch of the Interactive Plasma Physics Educational Experience (IPPEX)

    NASA Astrophysics Data System (ADS)

    Dominguez, A.; Rusaitis, L.; Zwicker, A.; Stotler, D. P.

    2015-11-01

    In the late 1990's PPPL's Science Education Department developed an innovative online site called the Interactive Plasma Physics Educational Experience (IPPEX). It featured (among other modules) two Java based applications which simulated tokamak physics: A steady state tokamak (SST) and a time dependent tokamak (TDT). The physics underlying the SST and the TDT are based on the ASPECT code which is a global power balance code developed to evaluate the performance of fusion reactor designs. We have relaunched the IPPEX site with updated modules and functionalities: The site itself is now dynamic on all platforms. The graphic design of the site has been modified to current standards. The virtual tokamak programming has been redone in Javascript, taking advantage of the speed and compactness of the code. The GUI of the tokamak has been completely redesigned, including more intuitive representations of changes in the plasma, e.g., particles moving along magnetic field lines. The use of GPU accelerated computation provides accurate and smooth visual representations of the plasma. We will present the current version of IPPEX as well near term plans of incorporating real time NSTX-U data into the simulation.

  18. Simulating the magnetized liner inertial fusion plasma confinement with smaller-scale experiments [Simulating the MagLIF plasma confinement with smaller-scale experiments

    SciTech Connect

    Ryutov, D. D.; Cuneo, M. E.; Herrmann, M. C.; Sinars, D. B.; Slutz, S. A.

    2012-06-20

    The recently proposed magnetized liner inertial fusion approach to a Z-pinch driven fusion [Slutz et al., Phys. Plasmas17, 056303 (2010)] is based on the use of an axial magnetic field to provide plasma thermal insulation from the walls of the imploding liner. The characteristic plasma transport regimes in the proposed approach cover parameter domains that have not been studied yet in either magnetic confinement or inertial confinement experiments. In this article, an analysis is presented of the scalability of the key physical processes that determine the plasma confinement. The dimensionless scaling parameters are identified and conclusion is drawn that the plasma behavior in scaled-down experiments can correctly represent the full-scale plasma, provided these parameters are approximately the same in two systems. Furthermore, this observation is important in that smaller-scale experiments typically have better diagnostic access and more experiments per year are possible.

  19. Graphite as a plasma-facing material in fusion experiments

    SciTech Connect

    Langley, R.A. )

    1989-01-01

    Graphite is now used extensively in most of the major fusion experiments in the world and will be used more extensively in future devices. In addition to its excellent tolerance of high heat fluxes, graphite has many unusual characteristics that pertain to its use as a plasma-facing material; these are its propensity for releasing gases when heated and when exposed to ion fluxes, its ability to absorb copious quantities of hydrogen during hydrogen bombardment, and its ability to pump hydrogen after noble gas bombardment. The graphite used in existing machines and considered for use in future machines is isotropic on a macroscopic scale and anisotropic on a microscopic scale; it has a large open porosity, up to 20%. This leads to enormous internal surface areas for adsorption and desorption of gases. Most early hydrogen-graphite interaction experiments were incorrectly analyzed because of this property. In addition, interaction of energetic hydrogen ions with graphite can lead to erosion, with concomitant deposition of carbon films with high hydrogen content on chamber surfaces. These effects are observed experimentally and have been modeled with some success. This paper presents experimental data dealing with these topics and their influences on present-day plasma operations and on graphite use in future machines. 34 refs., 8 figs., 1 tab.

  20. ISEE-1 data reduction and analysis plasma composition experiment

    NASA Technical Reports Server (NTRS)

    Lennartsson, W.; Sharp, R. D.

    1985-01-01

    The plasma composition experiment covers energies from OeV to 17 keV/e and has a mass-per-charge range from less than 1 to about 150 amu. Measurements were made from the inner ring current region to the plasma sheet, magnetotail lobes, and the magnetopause boundary layers and beyond. Possibly the most significant results from the experiment are those related to energetic (0+) ions of terrestrial origin. These ions are found in every region of the magnetosphere reached by the spacecraft and can have energy and pitch-angle distributions that are similar to those traditionally associated with protons of solar wind origin. The (0+) ions are commonly the most numerous ions in the 0.1 - 17 keV/e energy range and are often a substantial part of the ion population at large distances as well, especially during geomagnetically disturbed conditions. An overview of results obtained for the (0+) and other ions with energies in the 0.1 - 17 keV/e range in the magnetosphere is given.

  1. Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment, and Modeling

    PubMed Central

    Lee, Hyo-Chang; Chung, Chin-Wook

    2015-01-01

    Hysteresis, which is the history dependence of physical systems, is one of the most important topics in physics. Interestingly, bi-stability of plasma with a huge hysteresis loop has been observed in inductive plasma discharges. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics. PMID:26482650

  2. Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment, and Modeling.

    PubMed

    Lee, Hyo-Chang; Chung, Chin-Wook

    2015-10-20

    Hysteresis, which is the history dependence of physical systems, is one of the most important topics in physics. Interestingly, bi-stability of plasma with a huge hysteresis loop has been observed in inductive plasma discharges. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics.

  3. Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment, and Modeling

    NASA Astrophysics Data System (ADS)

    Lee, Hyo-Chang; Chung, Chin-Wook

    2015-10-01

    Hysteresis, which is the history dependence of physical systems, is one of the most important topics in physics. Interestingly, bi-stability of plasma with a huge hysteresis loop has been observed in inductive plasma discharges. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics.

  4. Proceedings of the 1st Space Plasma Computer Analysis Network (SCAN) Workshop. [space plasma computer networks

    NASA Technical Reports Server (NTRS)

    Green, J. L.; Waite, J. H.; Johnson, J. F. E.; Doupnik, J. R.; Heelis, R. A.

    1983-01-01

    The purpose of the workshop was to identify specific cooperative scientific study topics within the discipline of Ionosphere Magnetosphere Coupling processes and to develop methods and procedures to accomplish this cooperative research using SCAN facilities. Cooperative scientific research was initiated in the areas of polar cusp composition, O+ polar outflow, and magnetospheric boundary morphology studies and an approach using a common metafile structure was adopted to facilitate the exchange of data and plots between the various workshop participants. The advantages of in person versus remote workshops were discussed also.

  5. Electric Field Double Probe Measurements for Ionospheric Space Plasma Experiments

    NASA Technical Reports Server (NTRS)

    Pfaff, R.

    1999-01-01

    Double probes represent a well-proven technique for gathering high quality DC and AC electric field measurements in a variety of space plasma regimes including the magnetosphere, ionosphere, and mesosphere. Such experiments have been successfully flown on a variety of spacecraft including sounding rockets and satellites. Typical instrument designs involve a series of trades, depending on the science objectives, type of platform (e.g., spinning or 3-axis stabilized), expected plasma regime where the measurements will be made, available telemetry, budget, etc. In general, ionospheric DC electric field instruments that achieve accuracies of 0.1 mV/m or better, place spherical sensors at large distances (10m or more) from the spacecraft body in order to extend well beyond the spacecraft wake and sheath and to achieve large signal-to-noise ratios for DC and long wavelength measurements. Additional sets of sensors inboard of the primary, outermost sensors provide useful additional information, both for diagnostics of the plasma contact potentials, which particularly enhance the DC electric field measurements on non-spinning spacecraft, and for wavelength and phase velocity measurements that use the spaced receiver or "interferometer" technique. Accurate attitude knowledge enables B times V contributions to be subtracted from the measured potentials, and permits the measured components to be rotated into meaningful geophysical reference frames. We review the measurement technique for both DC and wave electric field measurements in the ionosphere discussing recent advances involving high resolution burst memories, multiple baseline double probes, new sensor surface materials, biasing techniques, and other considerations.

  6. The Madison plasma dynamo experiment: A facility for studying laboratory plasma astrophysics

    SciTech Connect

    Cooper, C. M.; Brookhart, M.; Collins, C.; Khalzov, I.; Milhone, J.; Nornberg, M.; Weisberg, D.; Forest, C. B.; Wallace, J.; Clark, M.; Flanagan, K.; Li, Y.; Nonn, P.; Ding, W. X.; Whyte, D. G.; Zweibel, E.

    2014-01-15

    The Madison plasma dynamo experiment (MPDX) is a novel, versatile, basic plasma research device designed to investigate flow driven magnetohydrodynamic instabilities and other high-β phenomena with astrophysically relevant parameters. A 3 m diameter vacuum vessel is lined with 36 rings of alternately oriented 4000 G samarium cobalt magnets, which create an axisymmetric multicusp that contains ∼14 m{sup 3} of nearly magnetic field free plasma that is well confined and highly ionized (>50%). At present, 8 lanthanum hexaboride (LaB{sub 6}) cathodes and 10 molybdenum anodes are inserted into the vessel and biased up to 500 V, drawing 40 A each cathode, ionizing a low pressure Ar or He fill gas and heating it. Up to 100 kW of electron cyclotron heating power is planned for additional electron heating. The LaB{sub 6} cathodes are positioned in the magnetized edge to drive toroidal rotation through J × B torques that propagate into the unmagnetized core plasma. Dynamo studies on MPDX require a high magnetic Reynolds number Rm > 1000, and an adjustable fluid Reynolds number 10 < Re < 1000, in the regime where the kinetic energy of the flow exceeds the magnetic energy (M{sub A}{sup 2}=(v/v{sub A}){sup 2}>1). Initial results from MPDX are presented along with a 0-dimensional power and particle balance model to predict the viscosity and resistivity to achieve dynamo action.

  7. Fundamental investigations of capacitive radio frequency plasmas: simulations and experiments

    NASA Astrophysics Data System (ADS)

    Donkó, Z.; Schulze, J.; Czarnetzki, U.; Derzsi, A.; Hartmann, P.; Korolov, I.; Schüngel, E.

    2012-12-01

    Capacitive radio frequency (RF) discharge plasmas have been serving hi-tech industry (e.g. chip and solar cell manufacturing, realization of biocompatible surfaces) for several years. Nonetheless, their complex modes of operation are not fully understood and represent topics of high interest. The understanding of these phenomena is aided by modern diagnostic techniques and computer simulations. From the industrial point of view the control of ion properties is of particular interest; possibilities of independent control of the ion flux and the ion energy have been utilized via excitation of the discharges with multiple frequencies. ‘Classical’ dual-frequency (DF) discharges (where two significantly different driving frequencies are used), as well as discharges driven by a base frequency and its higher harmonic(s) have been analyzed thoroughly. It has been recognized that the second solution results in an electrically induced asymmetry (electrical asymmetry effect), which provides the basis for the control of the mean ion energy. This paper reviews recent advances on studies of the different electron heating mechanisms, on the possibilities of the separate control of ion energy and ion flux in DF discharges, on the effects of secondary electrons, as well as on the non-linear behavior (self-generated resonant current oscillations) of capacitive RF plasmas. The work is based on a synergistic approach of theoretical modeling, experiments and kinetic simulations based on the particle-in-cell approach.

  8. Plasma-depleted holes, waves, and energized particles from high-altitude explosive plasma perturbation experiments

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.; Stenbaek-Nielsen, H. C.; Hallinan, T.; Deehr, C.; Romick, J.; Olson, J.; Kelley, M. C.; Pfaff, R.; Torbert, R. B.; Newell, P.

    1985-01-01

    The results of high-explosive shaped charge experiments King Crab and Bubble Machines I and II, intended to perturb the ambient plasma and magnetic field, are discussed. The instrumentation was flown above an altitude of 460 km in March 1980 and 1981 and comprised a single-axis dipole electric field detector, a fixed bias cylindrical Langmuir probe, a three-axis attitude magnetometer, and curved plated energetic ion and electron electrostatic analyzer. Among the effects of the explosion which are detailed, emphasis is placed on the creation of an ion-depleted dark hole during the Bubble Machine II experiment; mechanisms explaining the phenomenon are outlined. The auroral intensity ion beams with energies of up to 6.8 keV, observed following the explosion in the field-aligned ion electrostatic analyzer, are suggested to represent an existing ion conic population pitch angle scattered by the released barium into the view of the detector.

  9. Active experiments in space in conjunction with Skylab. [barium plasma injection experiment and magnetic storm of March 7, 1972

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.

    1974-01-01

    Two papers are presented which relate to the Skylab barium shaped charge experiments. The first describes the L=6.6 OOSIK barium plasma injection experiment and magnetic storm of March 7, 1972. Rocket payload, instrumentation, data reduction methods, geophysical environment at the time of the experiment, and results are given. The second paper presents the observation of an auroral Birkeland current which developed from the distortion of a barium plasma jet during the above experiment.

  10. Convex crystal x-ray spectrometer for laser plasma experiments

    SciTech Connect

    May, M.; Heeter, R.; Emig, J.

    2004-10-01

    Measuring time and space-resolved spectra is important for understanding Hohlraum and Halfraum plasmas. Experiments at the OMEGA laser have used the Nova TSPEC which was not optimized for the OMEGA diagnostic space envelope or for the needed spectroscopic coverage and resolution. An improved multipurpose spectrometer snout, the MSPEC, has been constructed and fielded on OMEGA. The MSPEC provides the maximal internal volume for mounting crystals without any beam interferences at either 2x or 3x magnification. The RAP crystal is in a convex mounting geometry bent to a 20 cm radius of curvature. The spectral resolution, E/dE, is about 200 at 2.5 keV. The spectral coverage is 2 to 4.5 keV. The MSPEC can record four separate spectra on the framing camera at time intervals of up to several ns. The spectrometer design and initial field-test performance will be presented and compared to that of the TSPEC.

  11. 94. DETAIL, SAME BEAN AS ABOVE, MARKED 'PATENTED DEC. 1ST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    94. DETAIL, SAME BEAN AS ABOVE, MARKED 'PATENTED DEC. 1ST 1857' - Smithsonian Institution Building, 1000 Jefferson Drive, between Ninth & Twelfth Streets, Southwest, Washington, District of Columbia, DC

  12. Absorption spectroscopy of a laboratory photoionized plasma experiment at Z

    SciTech Connect

    Hall, I. M.; Durmaz, T.; Mancini, R. C.; Bailey, J. E.; Rochau, G. A.; Golovkin, I. E.; MacFarlane, J. J.

    2014-03-15

    The Z facility at the Sandia National Laboratories is the most energetic terrestrial source of X-rays and provides an opportunity to produce photoionized plasmas in a relatively well characterised radiation environment. We use detailed atomic-kinetic and spectral simulations to analyze the absorption spectra of a photoionized neon plasma driven by the x-ray flux from a z-pinch. The broadband x-ray flux both photoionizes and backlights the plasma. In particular, we focus on extracting the charge state distribution of the plasma and the characteristics of the radiation field driving the plasma in order to estimate the ionisation parameter.

  13. Measurements of Plasma Expansion due to Background Gas in the Electron Diffusion Gauge Experiment

    SciTech Connect

    Kyle A. Morrison; Stephen F. Paul; Ronald C. Davidson

    2003-08-11

    The expansion of pure electron plasmas due to collisions with background neutral gas atoms in the Electron Diffusion Gauge (EDG) experiment device is observed. Measurements of plasma expansion with the new, phosphor-screen density diagnostic suggest that the expansion rates measured previously were observed during the plasma's relaxation to quasi-thermal-equilibrium, making it even more remarkable that they scale classically with pressure. Measurements of the on-axis, parallel plasma temperature evolution support the conclusion.

  14. Psychiatric Diagnosis and Concomitant Medical Treatment for 1st and 2nd Grade Children

    ERIC Educational Resources Information Center

    Cornell-Swanson, La Vonne; Frankenberger, William; Ley, Katie; Bowman, Krista

    2007-01-01

    This study examined the proportion of children in 1st and 2nd grade classes who were currently prescribed medication for psychotropic disorders. The study also examined the attitudes of 1st and 2nd grade teachers toward diagnosis of psychiatric disorders and use of psychiatric medication to treat children. Results of the current study indicate…

  15. Response to "Comment on `A large volume uniform plasma generator for the experiments of electromagnetic wave propagation in plasma'" [Phys. Plasmas 23, 094701 (2016)

    NASA Astrophysics Data System (ADS)

    Yang, Min; Li, Xiaoping; Xie, Kai; Liu, yanming; Liu, Donglin

    2016-09-01

    We respond to the issues raised in the comment by Eliseev and Kudryavtsev [Phys. Plasmas 23, 094701 (2016)]. We re-examine the principle of plasma generation and the operating situations in our plasma device, and some simplified models are founded to illustrate the qualitative relations between the pressure and the magnitude and uniformity of ne. We stand by our original conclusions in our plasma device that the magnitude and uniformity of ne are in roughly reverse proportion to the gas pressure in the chamber, as observed in the experiment.

  16. Simulating the magnetized liner inertial fusion plasma confinement with smaller-scale experiments

    SciTech Connect

    Ryutov, D. D.; Cuneo, M. E.; Herrmann, M. C.; Sinars, D. B.; Slutz, S. A.

    2012-06-15

    The recently proposed magnetized liner inertial fusion approach to a Z-pinch driven fusion [Slutz et al., Phys. Plasmas 17, 056303 (2010)] is based on the use of an axial magnetic field to provide plasma thermal insulation from the walls of the imploding liner. The characteristic plasma transport regimes in the proposed approach cover parameter domains that have not been studied yet in either magnetic confinement or inertial confinement experiments. In this article, an analysis is presented of the scalability of the key physical processes that determine the plasma confinement. The dimensionless scaling parameters are identified and conclusion is drawn that the plasma behavior in scaled-down experiments can correctly represent the full-scale plasma, provided these parameters are approximately the same in two systems. This observation is important in that smaller-scale experiments typically have better diagnostic access and more experiments per year are possible.

  17. Neutron computed tomography of plasma facing components for fusion experiments

    NASA Astrophysics Data System (ADS)

    Schillinger, B.; Greuner, H.; Linsmeier, Ch.

    2011-09-01

    In nuclear fusion experiments, divertor plates are used to remove energy and particles from the plasma. These divertor plates can be made of water-cooled copper heat sinks covered by carbon fiber composite (CFC) protection tiles. During operation, surface temperatures in excess of 1000 °C are reached for typical heat loads of 10 MW/m 2. The large mismatch in the coefficients of thermal expansion for CFC and Cu causes high stresses and possibly bonding defects. Growing joint defects, which lead to unacceptable overheating of the protection tiles, are critical for the lifetime of the components. A prototype component was subjected to 10,000 cycles at 10 MW/m 2 to study the crack growth mechanism. Neutron computed tomography offers the possibility to analyze such structures on centimeter-sized samples non-destructively with a high spatial resolution. At the ANTARES neutron imaging facility of the FRM II reactor, the samples were loaded with a contrast agent and examined with neutron computed tomography.

  18. Modeling ultrafast shadowgraphy in laser-plasma interaction experiments

    NASA Astrophysics Data System (ADS)

    Siminos, E.; Skupin, S.; Sävert, A.; Cole, J. M.; Mangles, S. P. D.; Kaluza, M. C.

    2016-06-01

    Ultrafast shadowgraphy is a new experimental technique that uses few-cycle laser pulses to image density gradients in a rapidly evolving plasma. It enables structures that move at speeds close to the speed of light, such as laser driven wakes, to be visualized. Here we study the process of shadowgraphic image formation during the propagation of a few cycle probe pulse transversely through a laser-driven wake using three-dimensional particle-in-cell simulations. In order to construct synthetic shadowgrams a near-field snapshot of the ultrashort probe pulse is analyzed by means of Fourier optics, taking into account the effect of a typical imaging setup. By comparing synthetic and experimental shadowgrams we show that the generation of synthetic data is crucial for the correct interpretation of experiments. Moreover, we study the dependence of synthetic shadowgrams on various parameters such as the imaging system aperture, the position of the object plane and the probe pulse delay, duration and wavelength. Finally, we show that time-dependent information from the interaction can be recovered from a single shot by using a broadband, chirped probe pulse and subsequent spectral filtering.

  19. Convex Crystal X-ray Spectrometer for Laser Plasma Experiments

    SciTech Connect

    May, M; Heeter, R; Emig, J

    2004-04-15

    Measuring time and space-resolved spectra is important for understanding Hohlraum and Halfraum plasmas. Experiments at the OMEGA laser have used the Nova TSPEC which was not optimized for the OMEGA diagnostic space envelope or for the needed spectroscopic coverage and resolution. An improved multipurpose spectrometer snout, the MSPEC, has been constructed and fielded on OMEGA. The MSPEC provides the maximal internal volume for mounting crystals without any beam interferences at either 2x or 3x magnification. The RAP crystal is in a convex mounting geometry bent to a 20 cm radius of curvature. The spectral resolution, E/dE, is about 200 at 2.5 keV. The spectral coverage is 2 to 4.5 keV. The MSPEC can record four separate spectra on the framing camera at time intervals of up to several ns. The spectrometer design and initial field-test performance will be presented and compared to that of the TSPEC. Work supported by U. S. DoE/UC LLNL contract W-7405-ENG-48

  20. Transverse oscillations in plasma wakefield experiments at FACET

    NASA Astrophysics Data System (ADS)

    Adli, E.; Lindstrøm, C. A.; Allen, J.; Clarke, C. I.; Frederico, J.; Gessner, S. J.; Green, S. Z.; Hogan, M. J.; Litos, M. D.; White, G. R.; Yakimenko, V.; An, W.; Clayton, C. E.; Marsh, K. A.; Mori, W. B.; Joshi, C.; Vafaei-Najafabadi, N.; Corde, S.; Lu, W.

    2016-09-01

    We study transverse effects in a plasma wakefield accelerator. Experimental data from FACET with asymmetry in the beam-plasma system is presented. Energy dependent centroid oscillations are observed on the accelerated part of the charge. The experimental results are compared to PIC simulations and theoretical estimates.

  1. AWAKE, The Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN

    NASA Astrophysics Data System (ADS)

    Gschwendtner, E.; Adli, E.; Amorim, L.; Apsimon, R.; Assmann, R.; Bachmann, A.-M.; Batsch, F.; Bauche, J.; Berglyd Olsen, V. K.; Bernardini, M.; Bingham, R.; Biskup, B.; Bohl, T.; Bracco, C.; Burrows, P. N.; Burt, G.; Buttenschön, B.; Butterworth, A.; Caldwell, A.; Cascella, M.; Chevallay, E.; Cipiccia, S.; Damerau, H.; Deacon, L.; Dirksen, P.; Doebert, S.; Dorda, U.; Farmer, J.; Fedosseev, V.; Feldbaumer, E.; Fiorito, R.; Fonseca, R.; Friebel, F.; Gorn, A. A.; Grulke, O.; Hansen, J.; Hessler, C.; Hofle, W.; Holloway, J.; Hüther, M.; Jaroszynski, D.; Jensen, L.; Jolly, S.; Joulaei, A.; Kasim, M.; Keeble, F.; Li, Y.; Liu, S.; Lopes, N.; Lotov, K. V.; Mandry, S.; Martorelli, R.; Martyanov, M.; Mazzoni, S.; Mete, O.; Minakov, V. A.; Mitchell, J.; Moody, J.; Muggli, P.; Najmudin, Z.; Norreys, P.; Öz, E.; Pardons, A.; Pepitone, K.; Petrenko, A.; Plyushchev, G.; Pukhov, A.; Rieger, K.; Ruhl, H.; Salveter, F.; Savard, N.; Schmidt, J.; Seryi, A.; Shaposhnikova, E.; Sheng, Z. M.; Sherwood, P.; Silva, L.; Soby, L.; Sosedkin, A. P.; Spitsyn, R. I.; Trines, R.; Tuev, P. V.; Turner, M.; Verzilov, V.; Vieira, J.; Vincke, H.; Wei, Y.; Welsch, C. P.; Wing, M.; Xia, G.; Zhang, H.

    2016-09-01

    The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world's first proton driven plasma wakefield acceleration experiment. The AWAKE experiment will be installed in the former CNGS facility and uses the 400 GeV/c proton beam bunches from the SPS. The first experiments will focus on the self-modulation instability of the long (rms ~12 cm) proton bunch in the plasma. These experiments are planned for the end of 2016. Later, in 2017/2018, low energy (~15 MeV) electrons will be externally injected into the sample wakefields and be accelerated beyond 1 GeV. The main goals of the experiment will be summarized. A summary of the AWAKE design and construction status will be presented.

  2. Electron beam-plasma interaction experiments with the Versatile Toroidal Facility (VTF)

    SciTech Connect

    Murphy, S.M.; Lee, M.C.; Moriarty, D.T.; Riddolls, R.J.

    1995-12-31

    The laboratory investigation of electron beam-plasma interactions is motivated by the recent space shuttle experiments. Interesting but puzzling phenomena were observed in the shuttle experiments such as the bulk heating of background ionospheric plasmas by the injected electron beams and the excitation of plasma waves in the frequency range of ELF waves. The plasma machine, the Versatile Toroidal Facility (VTF) can generate a large magnetized plasma with the electron plasma frequency greater than the electron gyrofrequency by a factor of 3--5 similar to the plasma condition in the ionosphere. Short pulses of electron beams are injected into the VTF plasmas in order to simulate the beam injection from spacecrafts in the ionosphere. A Langmuir probe installed at a bottom port of VTF monitors the spatial variation of electron beams emitted from LaB6 filaments. An energy analyzer has been used to determine the particle energy distribution in the VTF plasmas. Several mechanisms will be tested as potential causes of the bulk heating of background plasmas by the injected electron beams as seen in the space shuttle experiments. It is speculated that the observed ELF emissions result from the excitation of purely growing modes detected by the space shuttle-borne detectors. Results of the laboratory experiments will be reported to corroborate this speculation.

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

    NASA Astrophysics Data System (ADS)

    Jung, Soonwook

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

  4. Macroscopic lithotype characterisation of the 1st Middle-Polish (1st Lusatian) Lignite Seam in the Miocene of central Poland

    NASA Astrophysics Data System (ADS)

    Widera, Marek

    2012-03-01

    The 1st Middle-Polish (1st Lusatian) Lignite Seam is exploited in open-cast mines in central Poland. A large number of lignite lithotypes, grouped in four lithotype associations, are distinguished: xylitic, detritic, xylo-detritic and detro-xylitic lithotype associations, which show various structures. Each lithotype association was produced under specific peat-forming environmental conditions. In the case of the lignite seams under study they represent all the main environments that are known from Neogene mires, i.e.: fen or open water, bush moor, wet forest swamp and dry forest swamp. For a simple and practical description in the field of both the lignite sections and borehole cores, a new codification for lignite lithotypes is proposed. It is based on the codification of clastic deposits (lithofacies). The practical value of the new lignite lithotype codification is examined in three vertical sections of the 1st Middle-Polish Lignite Seam.

  5. Rare gas flow structuration in plasma jet experiments

    NASA Astrophysics Data System (ADS)

    Robert, E.; Sarron, V.; Darny, T.; Riès, D.; Dozias, S.; Fontane, J.; Joly, L.; Pouvesle, J.-M.

    2014-02-01

    Modifications of rare gas flow by plasma generated with a plasma gun (PG) are evidenced through simultaneous time-resolved ICCD imaging and schlieren visualization. The geometrical features of the capillary inside which plasma propagates before in-air expansion, the pulse repetition rate and the presence of a metallic target are playing a key role on the rare gas flow at the outlet of the capillary when the plasma is switched on. In addition to the previously reported upstream offset of the laminar to turbulent transition, we document the reverse action leading to the generation of long plumes at moderate gas flow rates together with the channeling of helium flow under various discharge conditions. For higher gas flow rates, in the l min-1 range, time-resolved diagnostics performed during the first tens of ms after the PG is turned on, evidence that the plasma plume does not start expanding in a laminar neutral gas flow. Instead, plasma ignition leads to a gradual laminar-like flow build-up inside which the plasma plume is generated. The impact of such phenomena for gas delivery on targets mimicking biological samples is emphasized, as well as their consequences on the production and diagnostics of reactive species.

  6. Plasma skin resurfacing: personal experience and long-term results.

    PubMed

    Bentkover, Stuart H

    2012-05-01

    This article presents a comprehensive clinical approach to plasma resurfacing for skin regeneration. Plasma technology, preoperative protocols, resurfacing technique, postoperative care, clinical outcomes, evidence-based results, and appropriate candidates for this procedure are discussed. Specific penetration depth and specific laser energy measurements are provided. Nitrogen plasma skin regeneration is a skin-resurfacing technique that offers excellent improvement of mild to moderate skin wrinkles and overall skin rejuvenation. It also provides excellent improvement in uniformity of skin color and texture in patients with hyperpigmentation with Fitzpatrick skin types 1 through 4. PMID:22537783

  7. UCLA/FNPL Underdense Plasma Lens Experiment: Results and Analysis

    SciTech Connect

    Thompson, M C; Badakov, H; Rosenzweig, J B; Travish, G; Fliller, R; Kazakevich, G M; Piot, P; Santucci, J; Li, J; Tikhoplav, R

    2006-08-04

    Focusing of a 15 MeV, 16 nC electron bunch by a gaussian underdense plasma lens operated just beyond the threshold of the underdense condition has been demonstrated. The strong 1.9 cm focal length plasma lens focused both transverse directions simultaneously and reduced the minimum area of the beam spot by a factor of 23. Analysis of the beam envelope evolution observed near the beam waist shows that the spherical aberrations of this underdense lens are lower than those of an overdense plasma lens, as predicted by theory. Time resolved measurements of the focused electron bunch are also reported and compared to simulations.

  8. Plasma skin resurfacing: personal experience and long-term results.

    PubMed

    Bentkover, Stuart H

    2012-05-01

    This article presents a comprehensive clinical approach to plasma resurfacing for skin regeneration. Plasma technology, preoperative protocols, resurfacing technique, postoperative care, clinical outcomes, evidence-based results, and appropriate candidates for this procedure are discussed. Specific penetration depth and specific laser energy measurements are provided. Nitrogen plasma skin regeneration is a skin-resurfacing technique that offers excellent improvement of mild to moderate skin wrinkles and overall skin rejuvenation. It also provides excellent improvement in uniformity of skin color and texture in patients with hyperpigmentation with Fitzpatrick skin types 1 through 4.

  9. Diagnostic Online Assessment of Basic IT Skills in 1st-Year Undergraduates in the Medical Sciences Division, University of Oxford

    ERIC Educational Resources Information Center

    Sieber, Vivien

    2009-01-01

    Attitude, experience and competence (broadly covered by the European Computer Driving Licence syllabus) in information technology (IT) were assessed in 846 1st-year Medical Sciences Division undergraduates (2003-06) at the start of their first term. Online assessments delivered during induction workshops were presented as an opportunity for…

  10. Plasma-filled applied B ion diode experiments using a plasma opening switch

    SciTech Connect

    Renk, T.J. )

    1994-12-15

    In order for a plasma opening switch (POS) to open quickly and transfer power efficiently from an inductively charged vacuum transmission line to an applied B ion diode, the load impedance of the ion diode may be required to have an initial low impedance phase. A plasma-filled diode has such an impedance history. To test the effect of a plasma-filled diode on POS-diode coupling, a drifting plasma was introduced from the cathode side of an applied B ion diode operated on the LION accelerator (1.5 MV, 4 [Omega], 40 ns) at Cornell University. This plasma readily crossed the 2.1 T magnetic insulation field of the diode, and resulted in both increased diode electrical power, and an increased ability of the ion beam to remove material from a target. The plasma did not appear to have a noticeable effect on local beam steering angle.

  11. Ion cyclotron heating experiments in magnetosphere plasma device RT-1

    SciTech Connect

    Nishiura, M. Yoshida, Z.; Yano, Y.; Kawazura, Y.; Saitoh, H.; Yamasaki, M.; Mushiake, T.; Kashyap, A.; Takahashi, N.; Nakatsuka, M.; Fukuyama, A.

    2015-12-10

    The ion cyclotron range of frequencies (ICRF) heating with 3 MHz and ∼10 kW is being prepared in RT-1. The operation regime for electron cyclotron resonance (ECR) heating is surveyed as the target plasmas. ECRH with 8.2 GHz and ∼50 kW produces the plasmas with high energy electrons in the range of a few ten keV, but the ions still remain cold at a few ten eV. Ion heating is expected to access high ion beta state and to change the aspect of plasma confinement theoretically. The ICRF heating is applied to the target plasma as an auxiliary heating. The preliminary result of ICRF heating is reported.

  12. Plasma wave experiment for the ISEE-3 mission

    NASA Technical Reports Server (NTRS)

    Scarf, F. L.

    1982-01-01

    Analysis of data from a scientific instrument designed to study solar wind and plasma wave phenomena on the ISEE-3 mission is presented. The performance of work on the data analysis phase is summarized.

  13. Initial Results from the Magnetized Dusty Plasma Experiment (MDPX)

    NASA Astrophysics Data System (ADS)

    Thomas, Edward; Konopka, Uwe; Lynch, Brian; Adams, Stephen; Leblanc, Spencer; Artis, Darrick; Dubois, Ami; Merlino, Robert; Rosenberg, Marlene

    2014-10-01

    The MDPX device is envisioned as a flexible, multi-user, research instrument that can perform a wide range of studies in fundamental and applied plasma physics. The MDPX device consists of two main components. The first is a four-coil, open bore, superconducting magnet system that is designed to produce uniform magnetic fields of up to 4 Tesla and non-uniform magnetic fields with gradients up to up to 2 T/m configurations. Within the warm bore of the magnet is placed an octagonal vacuum chamber that has a 46 cm outer diameter and is 22 cm tall. The primary missions of the MDPX device are to: (1) investigate the structural, thermal, charging, and collective properties of a plasma as the electrons, ions, and finally charged microparticles become magnetized; (2) study the evolution of a dusty plasma containing magnetic particles (paramagnetic, super-paramagnetic, or ferromagnetic particles) in the presence of uniform and non-uniform magnetic fields; and, (3) explore the fundamental properties of strongly magnetized plasmas (``i.e., dust-free'' plasmas). This presentation will summarize the initial characterization of the magnetic field structure, initial plasma parameter measurements, and the development of in-situ and optical diagnostics. This work is supported by funding from the NSF and the DOE.

  14. Experiments on rotamak plasma equilibrium and shape control

    SciTech Connect

    Petrov, Yuri; Yang Xiaokang; Wang Yonghui; Huang, T.-S.

    2010-01-15

    A set of magnetic shaping coils and copper rings is installed in cylindrical chamber rotamak to allow for an active equilibrium control in 40 ms plasma discharges. The coils, which are powered by programmable current source, are used to control both the plasma shape and the boundary poloidal magnetic flux. Without the active equilibrium control, the boundary flux drops from its vacuum value of 0.3 mWb to zero after the plasma current is generated. If the coils are activated, the boundary magnetic flux can be sustained within the 0.2-0.3 mWb range, thus keeping the separatrix away from chamber wall during whole period of the shot. The passive copper rings help in eliminating the fast variations of the boundary magnetic flux. The response of rotamak plasma to the active equilibrium control is drastically different in regimes with or without external toroidal field. A model is presented that describes the change in plasma shape, plasma current, and pressure under the effect of active equilibrium coils.

  15. Integrated predictive modelling simulations of burning plasma experiment designs

    NASA Astrophysics Data System (ADS)

    Bateman, Glenn; Onjun, Thawatchai; Kritz, Arnold H.

    2003-11-01

    Models for the height of the pedestal at the edge of H-mode plasmas (Onjun T et al 2002 Phys. Plasmas 9 5018) are used together with the Multi-Mode core transport model (Bateman G et al 1998 Phys. Plasmas 5 1793) in the BALDUR integrated predictive modelling code to predict the performance of the ITER (Aymar A et al 2002 Plasma Phys. Control. Fusion 44 519), FIRE (Meade D M et al 2001 Fusion Technol. 39 336), and IGNITOR (Coppi B et al 2001 Nucl. Fusion 41 1253) fusion reactor designs. The simulation protocol used in this paper is tested by comparing predicted temperature and density profiles against experimental data from 33 H-mode discharges in the JET (Rebut P H et al 1985 Nucl. Fusion 25 1011) and DIII-D (Luxon J L et al 1985 Fusion Technol. 8 441) tokamaks. The sensitivities of the predictions are evaluated for the burning plasma experimental designs by using variations of the pedestal temperature model that are one standard deviation above and below the standard model. Simulations of the fusion reactor designs are carried out for scans in which the plasma density and auxiliary heating power are varied.

  16. Laboratory-scale uranium RF plasma confinement experiments

    NASA Technical Reports Server (NTRS)

    Roman, W. C.

    1976-01-01

    An experimental investigation was conducted using 80 kW and 1.2 MW RF induction heater facilities to aid in developing the technology necessary for designing a self-critical fissioning uranium plasma core reactor. Pure uranium hexafluoride (UF6) was injected into argon-confined, steady-state, RF-heated plasmas in different uranium plasma confinement tests to investigate the characteristics of plamas core nuclear reactors. The objectives were: (1) to confine as high a density of uranium vapor as possible within the plasma while simultaneously minimizing the uranium compound wall deposition; (2) to develop and test materials and handling techniques suitable for use with high-temperature, high-pressure gaseous UF6; and (3) to develop complementary diagnostic instrumentation and measurement techniques to characterize the uranium plasma and residue deposited on the test chamber components. In all tests, the plasma was a fluid-mechanically-confined vortex-type contained within a fused-silica cylindrical test chamber. The test chamber peripheral wall was 5.7 cm ID by 10 cm long.

  17. Experiments on a current-toggled plasma-opening switch

    SciTech Connect

    Mendel, C.W. Jr.; Savage, M.E.; Zagar, D.M.; Simpson, W.W.; Grasser, T.W.; Quintenz, J.P. )

    1992-04-15

    Plasma-opening switches have been used to improve pulsed-power wave shapes for over a decade. These switches have used the inertia of the plasma to hold the switch closed. This results in conflicting requirements when long hold-off time and fast opening are required, and also results in variation in opening current due to variation in initial plasma fill. The current-toggled plasma-opening switch attempts to overcome these problems by using external magnetic fields rather than inertia to control the plasma conductor. Data will be presented showing several features of the operation of this switch. These data will be compared to models used to design the switch. The comparisons indicate that the mass can be measured approximately from fast coil data and that the slow coil flux does set the opening level of the current. They also indicate that the opening current is somewhat dependent upon plasma mass, and that the design of the field coils that provide the control fields must be done more carefully to provide a switch that opens satisfactorily.

  18. Experiments of discharge guiding using strongly and weakly ionized plasma channels for laser-triggered lightning

    NASA Astrophysics Data System (ADS)

    Shimada, Yoshinori; Uchida, Shigeaki; Yamanaka, Chiyoe; Ogata, Akihisa; Yamanaka, Tatsuhiko; Kawasaki, Zen-ichiro; Fujiwara, Etsuo; Ishikubo, Yuji; Kawabata, Kinya

    2000-01-01

    Generation of a long laser-plasma channel capable of triggering and guiding an electrical discharge is a crucial issue for laser-triggering protection system. We make a long plasma channel to increase the probability of triggered lightning by laser. To produce a long laser plasma channel, we propose da new technique called hybrid plasma channel method which combines weakly and strongly ionized plasma channels to maximize laser-energy efficiency of discharge guiding. We investigate the characteristics of the hybrid plasma channels to maximize laser-energy efficiency of discharge guiding. We investigate the characteristics of the hybrid plasma channel method through several laboratory experiments. The weakly ionized channel was generated by UV laser pulses in air. As the number density of electrons in weakly ionized channel is proportional to 1.1 power of laser intensity, nitrogen and oxygen molecules can not attributed to the source of ionized plasma. It is suggested that dissociation process of impurities in air whose density is 1011 - 1012 cm-3 plays an important role in plasma formation and leader triggering effect. The 50 percent flashover voltage using the hybrid plasma channel method is lower than that without the weakly ionized plasma channel. It was also found that higher repetition rate of the plasma generation on lowers the V50 furthermore.

  19. Review of upconverted Nd-glass laser plasma experiments at the Lawrence Livermore National Laboratory

    SciTech Connect

    Manes, K.R.

    1982-05-01

    Systematic scaling experiments aimed at deducing the dependence of laser-plasma interaction phenomena on target plasma material and target irradiation history have been underway in laboratories all over the world in recent years. During 1980 and 1981 the Livermore program undertook to measure the laser light absorption of high and low Z plasmas and the partition of the absorbed energy amongst the thermal and suprathermal electron populations as a function of both laser intensity and wavelength. Simulations suggested that short wavelength laser light would couple more efficiently than longer wavelengths to target plasmas. Shorter wavelength heating of higher electron plasma densities would, it was felt, lead to laser-plasma interactions freer of anomalous absorption processes. The following sections review LLNL experiments designed to test these hypotheses.

  20. Waves In Space Plasmas (WISP): A space plasma lab active experiment

    NASA Technical Reports Server (NTRS)

    Fredricks, R. W.

    1983-01-01

    The Waves in Space Plasmas (WISP) series of Spacelab Space Plasma Labs devoted to active experimentation, are introduced. Space Plasma Lab-1 is keyed to active probing of the ionosphere and magnetosphere using controlled wave injections by the WISP VLF and HF transmitters, supported by a free-flying plasma diagnostics package instrumented with wave receivers and particle probe diagnostics, designed to measure radiation and propagation of plasma waves, precipitated particle fluxes due to wave/particle interactions, and similar phenomena resulting from wave injectons. The VLF transmitter delivers up to 1 kW of RF power into the antenna terminals over the range from 0.3 to 30 kHz. The HF transmitter delivers up to 500 W to the antenna over the range from 1 to 30 MHz. A dipole antenna commandable to any extension up to 300 m tip-to-tip is available.

  1. First experiments probing the collision of parallel magnetic fields using laser-produced plasmas

    SciTech Connect

    Rosenberg, M. J.; Li, C. K.; Fox, W.; Igumenshchev, I.; Seguin, F. H.; Town, R. P.; Frenje, J. A.; Stoeckl, C.; Glebov, V.; Petrasso, R. D.

    2015-04-08

    Novel experiments to study the strongly-driven collision of parallel magnetic fields in β~10, laser-produced plasmas have been conducted using monoenergetic proton radiography. These experiments were designed to probe the process of magnetic flux pileup, which has been identified in prior laser-plasma experiments as a key physical mechanism in the reconnection of anti-parallel magnetic fields when the reconnection inflow is dominated by strong plasma flows. In the present experiments using colliding plasmas carrying parallel magnetic fields, the magnetic flux is found to be conserved and slightly compressed in the collision region. Two-dimensional (2D) particle-in-cell (PIC) simulations predict a stronger flux compression and amplification of the magnetic field strength, and this discrepancy is attributed to the three-dimensional (3D) collision geometry. Future experiments may drive a stronger collision and further explore flux pileup in the context of the strongly-driven interaction of magnetic fields.

  2. Texas Reports 1st U.S. Case of Zika from Travel to Another State

    MedlinePlus

    ... 160450.html Texas Reports 1st U.S. Case of Zika From Travel to Another State Resident had recently ... what appears to be the first case of Zika infection traveling across state lines, Texas health officials ...

  3. 45. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    45. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st St. S., Columbus, Ms. Turn span from SE. Sarcone Photography, Columbus, Ms. Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  4. 46. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    46. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st St. S., Columbus, Ms. Overall view, from S. Sarcone Photography, Columbus, Ms. Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  5. BLOEDNER MONUMENT (32ND INDIANA, 1ST GERMAN MONUMENT), SECTION C, FRONT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    BLOEDNER MONUMENT (32ND INDIANA, 1ST GERMAN MONUMENT), SECTION C, FRONT ELEVATION DETAIL OF GERMAN TEXT. VIEW TO NORTHEAST. - Cave Hill National Cemetery, 701 Baxter Avenue, Louisville, Jefferson County, KY

  6. U.S. Premature Births Rise for 1st Time in 8 Years

    MedlinePlus

    ... 161792.html U.S. Premature Births Rise for 1st Time in 8 Years March of Dimes' report finds ... United States increased in 2015 for the first time in eight years, and rates are especially high ...

  7. 28. ENGINE CLUSTER OF 1ST STAGE OF A SATURN I ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. ENGINE CLUSTER OF 1ST STAGE OF A SATURN I ROCKET ENGINE LOCATED ON NORTH SIDE OF STATIC TEST STAND. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

  8. VIEW SOUTH/SOUTHEAST LOOKING DOWN ON 2ND AQUEDUCT AND 1ST AQUEDUCT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW SOUTH/SOUTHEAST LOOKING DOWN ON 2ND AQUEDUCT AND 1ST AQUEDUCT CASCADES TOWARDS FILTRATION PLANT AND LOS ANGELES RESERVOIR - Los Angeles Aqueduct, Cascades Structures, Los Angeles, Los Angeles County, CA

  9. 4. VIEW WEST, WEST SIDE, SHOWING CHANNELS 1ST AND 2ND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW WEST, WEST SIDE, SHOWING CHANNELS 1ST AND 2ND VERTICAL BRACED DOUBLE ANGLES, DIAGONAL BRACING AND CROSS BRACED RAILING - Thirty-Sixth Street Bridge, Spanning Rabbit River, Hamilton, Allegan County, MI

  10. 14. Building 105, Facilities Engineering Building, 1830, interior, 1st floor, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Building 105, Facilities Engineering Building, 1830, interior, 1st floor, crib area of building, showing electrical and plumbing cribs, wall and ceiling detail, looking S. - Watervliet Arsenal, Building 105, South Broadway, on Hudson River, Watervliet, Albany County, NY

  11. 7. 1ST FLOOR, LOOKING SOUTH SHOWING DINING ROOM FIREPLACE (LEFT); ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. 1ST FLOOR, LOOKING SOUTH SHOWING DINING ROOM FIREPLACE (LEFT); ENTRY SITTING ROOM FIREPLACE (RIGHT) AND LIVING ROOM (BACKGROUND). - Fort Riley, Building No. 4, 4 Barry Avenue, Riley, Riley County, KS

  12. Florida Reports 1st Locally Transmitted Zika Infections in U.S.

    MedlinePlus

    ... fullstory_160151.html Florida Reports 1st Locally Transmitted Zika Infections in U.S. 4 cases likely originated from ... apparently experiencing its first local outbreak of the Zika virus, with four human infections reported in South ...

  13. 62. Neg. No. F75A, Jun 18, 1930, INTERIORWAREHOUSE, 1ST FLOOR, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    62. Neg. No. F-75A, Jun 18, 1930, INTERIOR-WAREHOUSE, 1ST FLOOR, STORAGE OF AUTOMOBILE COMPONENTS - Ford Motor Company Long Beach Assembly Plant, Assembly Building, 700 Henry Ford Avenue, Long Beach, Los Angeles County, CA

  14. MAGAZINE E30. VIEW FROM BETWEEN 1ST AND 2ND BLAST WALL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    MAGAZINE E-30. VIEW FROM BETWEEN 1ST AND 2ND BLAST WALL LOOKING TO THE REAR OF THE MAGAZINE. - Naval Magazine Lualualei, Waikele Branch, Tunnel Magazine Type, Waikakalaua & Kipapa Gulches, Pearl City, Honolulu County, HI

  15. 19. Detail of brick courses 116, back side, between 1st ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. Detail of brick courses 1-16, back side, between 1st and 2nd windows from the right - Oklahoma State University, Boys Dormitory, Northwest corner of Hester Street & Athletic Avenue, Stillwater, Payne County, OK

  16. 20. Detail of brick courses 4675, back side, between 1st ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. Detail of brick courses 46-75, back side, between 1st and 2nd windows from the right - Oklahoma State University, Boys Dormitory, Northwest corner of Hester Street & Athletic Avenue, Stillwater, Payne County, OK

  17. If 1st Baby's Early, 2nd Will Be Too: Study

    MedlinePlus

    ... If 1st Baby's Early, 2nd Will Be Too: Study Chances just as high for women who go ... it really is a potent factor," said senior study author Laura Jelliffe-Pawlowski. She is associate director ...

  18. Experiment and Results on Plasma Etching of SRF cavities

    SciTech Connect

    Upadhyay, Janardan; Im, Do; Peshl, J.; Vuskovic, Leposova; Popovic, Svetozar; Valente, Anne-Marie; Phillips, H. Lawrence

    2015-09-01

    The inner surfaces of SRF cavities are currently chemically treated (etched or electropolished) to achieve the state of the art RF performance. We designed an apparatus and developed a method for plasma etching of the inner surface for SRF cavities. The process parameters (pressure, power, gas concentration, diameter and shape of the inner electrode, temperature and positive dc bias at inner electrode) are optimized for cylindrical geometry. The etch rate non-uniformity has been overcome by simultaneous translation of the gas point-of-entry and the inner electrode during the processing. A single cell SRF cavity has been centrifugally barrel polished, chemically etched and RF tested to establish a baseline performance. This cavity is plasma etched and RF tested afterwards. The effect of plasma etching on the RF performance of this cavity will be presented and discussed.

  19. Commercialization of Plasma-Assisted Technologies: The Indian Experience

    NASA Astrophysics Data System (ADS)

    John, P. I.

    The paper describes an initiative by the Institute for Plasma Research (IPR), India in establishing links with the Indian industry for developing and commercialising advanced plasma-based industrial technologies. This has culminated in the creation of a self-financing technology development, incubation, demonstration and delivery facility. A business plan for converting the knowledge base to commercially viable technologies conceived technology as a product and the industry as the market and addressed issues like resistance to new technologies, the key role of entrepreneur, thrust areas and the necessity of technology incubation and delivery. Success of this strategy is discussed in a few case studies. We conclude by identifying the cost, environmental, strategic and techno-economic aspects, which would be the prime drivers for plasma-assisted manufacturing technology in India.

  20. Plasma isotopic changeover experiments in JET under carbon and ITER-like wall conditions

    NASA Astrophysics Data System (ADS)

    Loarer, T.; Brezinsek, S.; Philipps, V.; Romanelli-Gruenhagen, S.; Alves, D.; Carvalho, I.; Felton, R.; Douai, D.; Esser, H. G.; Frigione, D.; Smith, R.; Stamp, M. F.; Reux, C.; Vartanian, S.; Contributors, JET

    2015-04-01

    In JET-ILW isotopic plasma wall changeover experiments have been carried out to determine the amount of particles accessible by changing the plasma from H to D and from D to H. The gas balance analysis integrated over the experimental sessions show that the total amount of H or D removed from the wall is in the range of (1-3) × 1022D. For both changeover experiments, the respective plasma isotopic ratio behaviour is exactly the same as a function of the pulse number. After only 80 s of plasma (4 pulses), the plasma isotopic ratio is lower than 10%, below 4.5% after 13 pulses and then saturates around ˜2-3%. In these conditions, the removal efficiency through plasma operation becomes very poor. The saturation of the plasma isotopic ratio in the range of 10% is also observed for the JET-C configuration although the amount of tritium retained in the vessel after the DT pulses was more than one order of magnitude compared to the retention observed with the JET-ILW. This demonstrates that the amount of particle recovery through plasma changeover is independent from the long term retention. Since this long term reservoir results from codeposition, these experiments suggest that there is a limited access to these codeposited particles by plasma isotopic changeover. Finally, in ITER, change over from D/T to H at the end of the discharge for possibly reducing the long term retention does not appear as a good strategy.

  1. Experiments on Ion-Ion Plasmas From Discharges

    NASA Astrophysics Data System (ADS)

    Leonhardt, Darrin; Walton, Scott; Blackwell, David; Murphy, Donald; Fernsler, Richard; Meger, Robert

    2001-10-01

    Use of both positive and negative ions in plasma processing of materials has been shown to be advantageous[1] in terms of better feature evolution and control. In this presentation, experimental results are given to complement recent theoretical work[2] at NRL on the formation and decay of pulsed ion-ion plasmas in electron beam generated discharges. Temporally resolved Langmuir probe and mass spectrometry are used to investigate electron beam generated discharges during the beam on (active) and off (afterglow) phases in a variety of gas mixtures. Because electron-beam generated discharges inherently[3] have low electron temperatures (<0.5eV in molecular gases), negative ion characteristics are seen in the active as well as afterglow phases since electron detachment increases with low electron temperatures. Analysis of temporally resolved plasma characteristics deduced from these measurements will be presented for pure O_2, N2 and Ar and their mixtures with SF_6. Oxygen discharges show no noticeable negative ion contribution during the active or afterglow phase, presumably due to the higher energy electron attachment threshold, which is well above any electron temperature. In contrast, SF6 discharges demonstrate ion-ion plasma characteristics in the active glow and are completely ion-ion in the afterglow. Comparison between these discharges with published cross sections and production mechanisms will also be presented. [1] T.H. Ahn, K. Nakamura & H. Sugai, Plasma Sources Sci. Technol., 5, 139 (1996); T. Shibyama, H. Shindo & Y. Horiike, Plasma Sources Sci. Technol., 5, 254 (1996). [2] See presentation by R. F. Fernsler, at this conference. [3] D. Leonhardt, et al., 53rd Annual GEC, Houston, TX.

  2. Data processing of absorption spectra from photoionized plasma experiments at Z

    SciTech Connect

    Hall, I. M.; Durmaz, T.; Mancini, R. C.; Bailey, J. E.; Rochau, G. A.

    2010-10-15

    We discuss the processing of x-ray absorption spectra from photoionized plasma experiments at Z. The data was recorded with an imaging spectrometer equipped with two elliptically bent potassium acid phthalate (KAP) crystals. Both time-integrated and time-resolved data were recorded. In both cases, the goal is to obtain the transmission spectra for quantitative analysis of plasma conditions.

  3. Study of plasma start-up initiated by second harmonic electron cyclotron resonance heating on WEGA experiment

    SciTech Connect

    Preynas, M.; Laqua, H. P.; Otte, M.; Stange, T.; Aßmus, D.; Wauters, T.

    2014-02-12

    Although both 1st harmonic ordinary mode (O1) and 2nd harmonic extra-ordinary mode (X2) have been successfully used to initiate pre-ionization and breakdown in many devices, a complete theoretical model is still missing to explain the success of this method. Moreover, some experimental observations are not completely understood, such as what occurs during the delay time between the turn-on of ECRH power and first signals of density or light measurements. Since during this free period the ECRH power has to be absorbed by in-vessel components, it is of prime importance to know what governs this delay time. Recently, dedicated start-up experiments have been performed on WEGA, using a 28 GHz ECRH system in X2-mode. This machine has the interesting capability to be run also as a tokamak allowing comparative experiments between stellarator (ι/2π > 0) and tokamak (ι/2π = 0) configurations. Different scans in heating power, neutral gas pressure, and rotational transform (ι) show clearly that the start-up is a two step process. A first step following the turn-on of the ECRH power during which no measurable electron density (or just above the noise level in some cases), ECE and radiated power is detected. Its duration depends strongly on the level of injected power. The second step corresponds to the gas ionization and plasma expansion phase, with a velocity of density build-up and filling-up of the vessel volume depending mainly on pressure, gas and rotational transform. Moreover, an interesting scenario of ECRH pre-ionization without loop voltage in tokamak configuration by applying a small optimal vertical field is relevant for start-up assistance on future experiments like ITER. The results from this experimental parametric study are useful for the modeling of the start-up assisted by the second harmonic electron cyclotron resonance heating. The aim of this work is to establish predictive scenarios for both ITER and W7-X operation.

  4. 1st- and 2nd-order motion and texture resolution in central and peripheral vision

    NASA Technical Reports Server (NTRS)

    Solomon, J. A.; Sperling, G.

    1995-01-01

    STIMULI. The 1st-order stimuli are moving sine gratings. The 2nd-order stimuli are fields of static visual texture, whose contrasts are modulated by moving sine gratings. Neither the spatial slant (orientation) nor the direction of motion of these 2nd-order (microbalanced) stimuli can be detected by a Fourier analysis; they are invisible to Reichardt and motion-energy detectors. METHOD. For these dynamic stimuli, when presented both centrally and in an annular window extending from 8 to 10 deg in eccentricity, we measured the highest spatial frequency for which discrimination between +/- 45 deg texture slants and discrimination between opposite directions of motion were each possible. RESULTS. For sufficiently low spatial frequencies, slant and direction can be discriminated in both central and peripheral vision, for both 1st- and for 2nd-order stimuli. For both 1st- and 2nd-order stimuli, at both retinal locations, slant discrimination is possible at higher spatial frequencies than direction discrimination. For both 1st- and 2nd-order stimuli, motion resolution decreases 2-3 times more rapidly with eccentricity than does texture resolution. CONCLUSIONS. (1) 1st- and 2nd-order motion scale similarly with eccentricity. (2) 1st- and 2nd-order texture scale similarly with eccentricity. (3) The central/peripheral resolution fall-off is 2-3 times greater for motion than for texture.

  5. Plasma wave experiment for the ISEE-3 mission

    NASA Technical Reports Server (NTRS)

    Scarf, F. L.

    1983-01-01

    An analysis of data from a scientific instrument designed to study solar wind and plasma wave phenomena on the ISEE-3 Mission is provided. Work on the data analysis phase of the contract from 1 October 1982 through 30 March 1983 is summarized.

  6. Slowing of magnetic reconnection concurrent with weakening plasma inflows and increasing collisionality in strongly-driven laser-plasma experiments

    DOE PAGES

    Rosenberg, M.  J.; Li, C.  K.; Fox, W.; Zylstra, A.  B.; Stoeckl, C.; Séguin, F.  H.; Frenje, J.  A.; Petrasso, R. D.

    2015-05-20

    An evolution of magnetic reconnection behavior, from fast jets to the slowing of reconnection and the establishment of a stable current sheet, has been observed in strongly-driven, β ≲ 20 laser-produced plasma experiments. This process has been inferred to occur alongside a slowing of plasma inflows carrying the oppositely-directed magnetic fields as well as the evolution of plasma conditions from collisionless to collisional. High-resolution proton radiography has revealed unprecedented detail of the forced interaction of magnetic fields and super-Alfvénic electron jets (Vjet~ 20VA) ejected from the reconnection region, indicating that two-fluid or collisionless magnetic reconnection occurs early in time. Themore » absence of jets and the persistence of strong, stable magnetic fields at late times indicates that the reconnection process slows down, while plasma flows stagnate and plasma conditions evolve to a cooler, denser, more collisional state. These results demonstrate that powerful initial plasma flows are not sufficient to force a complete reconnection of magnetic fields, even in the strongly-driven regime.« less

  7. Slowing of magnetic reconnection concurrent with weakening plasma inflows and increasing collisionality in strongly-driven laser-plasma experiments

    SciTech Connect

    Rosenberg, M.  J.; Li, C.  K.; Fox, W.; Zylstra, A.  B.; Stoeckl, C.; Séguin, F.  H.; Frenje, J.  A.; Petrasso, R. D.

    2015-05-20

    An evolution of magnetic reconnection behavior, from fast jets to the slowing of reconnection and the establishment of a stable current sheet, has been observed in strongly-driven, β ≲ 20 laser-produced plasma experiments. This process has been inferred to occur alongside a slowing of plasma inflows carrying the oppositely-directed magnetic fields as well as the evolution of plasma conditions from collisionless to collisional. High-resolution proton radiography has revealed unprecedented detail of the forced interaction of magnetic fields and super-Alfvénic electron jets (Vjet~ 20VA) ejected from the reconnection region, indicating that two-fluid or collisionless magnetic reconnection occurs early in time. The absence of jets and the persistence of strong, stable magnetic fields at late times indicates that the reconnection process slows down, while plasma flows stagnate and plasma conditions evolve to a cooler, denser, more collisional state. These results demonstrate that powerful initial plasma flows are not sufficient to force a complete reconnection of magnetic fields, even in the strongly-driven regime.

  8. Experiments with an rf dusty plasma and an external plasma jet

    NASA Astrophysics Data System (ADS)

    Ticoş, C. M.

    2010-12-01

    A plasma jet produced in a coaxial plasma gun was aimed at a cloud of dust particles levitated in the sheath of a radio-frequency (rf) plasma produced between two parallel-plate electrodes. A high-speed camera with a side-view on the dust cloud was used to track the dust particles. Several cases of dust motion could be observed. When the jet was parallel with the horizontal electrodes of the rf plasma the dust particles were either pushed out of the trapping region by the plasma jet or were only perturbed from their equilibrium position, oscillating with a frequency of the order of a few kHz. In the first case the trajectory of the dust particles followed the curvature of the sheath. In the second case, when the jet was fired at a small angle with the horizontal electrodes the dust particles hit the bottom electrode and ricocheted back into the sheath. Finally, another situation was observed when the jet perturbed the rf plasma and its sheath and the whole dust crystal fell to the electrode.

  9. High temperature UF6 RF plasma experiments applicable to uranium plasma core reactors

    NASA Technical Reports Server (NTRS)

    Roman, W. C.

    1979-01-01

    An investigation was conducted using a 1.2 MW RF induction heater facility to aid in developing the technology necessary for designing a self critical fissioning uranium plasma core reactor. Pure, high temperature uranium hexafluoride (UF6) was injected into an argon fluid mechanically confined, steady state, RF heated plasma while employing different exhaust systems and diagnostic techniques to simulate and investigate some potential characteristics of uranium plasma core nuclear reactors. The development of techniques and equipment for fluid mechanical confinement of RF heated uranium plasmas with a high density of uranium vapor within the plasma, while simultaneously minimizing deposition of uranium and uranium compounds on the test chamber peripheral wall, endwall surfaces, and primary exhaust ducts, is discussed. The material tests and handling techniques suitable for use with high temperature, high pressure, gaseous UF6 are described and the development of complementary diagnostic instrumentation and measurement techniques to characterize the uranium plasma, effluent exhaust gases, and residue deposited on the test chamber and exhaust system components is reported.

  10. Structural and Dynamic Phenomena in the ``Plasma Kristall-4'' Experiments under Microgravity Conditions

    NASA Astrophysics Data System (ADS)

    Usachev, A. D.; Zobnin, A. V.; Petrov, O. F.; Fortov, V. E.; Thoma, M. H.; Höfner, H.; Kretschmer, M.; Fink, M.; Morfill, G. E.

    2011-11-01

    New results from the recent experiments using the "Plasma Kristall-4", "PK-4", onboard of the parabolic flight plane A-300 Zero-G are presented. These are: a) structural and dynamics properties of dusty plasma clouds containing elongated dust particles—microrods; b) formation of a boundary-free dust cluster due to attractive forces caused by ion fluxes in a bulk plasma region; c) shock wave in dusty plasma driven by the electrical manipulative electrode in polarity switching direct current discharge. Physical models of the observed phenomena are presented and discussed. Universal possibilities of the "PK-4" setup are demonstrated.

  11. Early results of microwave transmission experiments through an overly dense rectangular plasma sheet with microparticle injection

    SciTech Connect

    Gillman, Eric D.; Amatucci, W. E.

    2014-06-15

    These experiments utilize a linear hollow cathode to create a dense, rectangular plasma sheet to simulate the plasma layer surrounding vehicles traveling at hypersonic velocities within the Earth's atmosphere. Injection of fine dielectric microparticles significantly reduces the electron density and therefore lowers the electron plasma frequency by binding a significant portion of the bulk free electrons to the relatively massive microparticles. Measurements show that microwave transmission through this previously overly dense, impenetrable plasma layer increases with the injection of alumina microparticles approximately 60 μm in diameter. This method of electron depletion is a potential means of mitigating the radio communications blackout experienced by hypersonic vehicles.

  12. Early results of microwave transmission experiments through an overly dense rectangular plasma sheet with microparticle injection

    NASA Astrophysics Data System (ADS)

    Gillman, Eric D.; Amatucci, W. E.

    2014-06-01

    These experiments utilize a linear hollow cathode to create a dense, rectangular plasma sheet to simulate the plasma layer surrounding vehicles traveling at hypersonic velocities within the Earth's atmosphere. Injection of fine dielectric microparticles significantly reduces the electron density and therefore lowers the electron plasma frequency by binding a significant portion of the bulk free electrons to the relatively massive microparticles. Measurements show that microwave transmission through this previously overly dense, impenetrable plasma layer increases with the injection of alumina microparticles approximately 60 μm in diameter. This method of electron depletion is a potential means of mitigating the radio communications blackout experienced by hypersonic vehicles.

  13. An enhancement of plasma density by neutral gas injection observed in SEPAC Spacelab-1 experiment

    NASA Technical Reports Server (NTRS)

    Sasaki, S.; Kawashima, N.; Kuriki, K.; Yanagisawa, M.; Obayashi, T.; Kubota, S.; Roberts, W. T.; Reasoner, D. L.; Taylor, W. W. L.; Williamson, P. R.

    1985-01-01

    An enhancement of plasma density observed during a neutral gas injection in Space Experiments with Particle Accelerators by the Space Shuttle/Spacelab-1 is presented. When a plume of nitrogen gas was injected from the orbiter into space, a large amount of plasma was detected by an onboard plasma probe. The observed density often increased beyond the background plasma density and was strongly dependent on the attitude of the orbiter with respect to the velocity vector. This effect has been explained by a collisional interaction between the injected gas molecules and the ionospheric ions relatively drifting at the orbital speed.

  14. 1st Advanced Marine Renewable Energy Instrumentation Experts Workshop: April 5-7, 2011

    SciTech Connect

    Not Available

    2011-10-01

    The U.S. marine energy industry is actively pursuing development of offshore wind and marine hydrokinetic (MHK) energy systems. Experience in the wind energy sector demonstrates that new technology development requires thorough measurement and characterization of the environmental conditions prevalent at installation sites and of technology operating in the field. Presently, there are no turn-key instrumentation system solutions that meet the measurement needs of the marine energy industry. The 1st Advanced Marine Renewable Energy Instrumentation Experts Workshop brought together technical experts from government laboratories, academia, and industry representatives from marine energy, wind, offshore oil and gas, and instrumentation developers to present and discuss the instrumentation needs of the marine energy industry. The goals of the meeting were to: (1) Share the latest relevant knowledge among technical experts; (2) Review relevant state-of-the-art field measurement technologies and methods; (3) Review lessons learned from recent field deployments; (4) Identify synergies across different industries; (5) Identify gaps between existing and needed instrumentation capabilities; (6) Understand who are the leading experts; (7) Provide a forum where stakeholders from the marine energy industry could provide substantive input in the development of new marine energy field deployable instrumentation packages.

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  16. Incorporation of the Data Acquisition System with a Small Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    Nolan, Stephen; James, R. W.; Page, E. L.; Zuniga, J.; Schlank, C.; Lopez, M.; Sherman, J.; Stutzman, B. S.

    2012-10-01

    At the Coast Guard Academy Plasma Lab (CGAPL), a small Helicon Plasma Experiment (HPX) is being developed to utilize the reputed high densities (10^13 cm-3 and higher) at low pressure (.01 T) [1], in high temperature and density diagnostic development for future laboratory investigations. With first plasmas at hand, HPX is constructing triple and mach particle probes, magnetic probes, and a single point Thompson Scattering system for HPX plasma property investigations. A 32-channel National Instruments Data Acquisition (DAQ) Board capable of sampling at 12 bits of precision at 2 MS/s and running multiple simultaneous experiments is currently under construction. This DAQ System with integrated storage and GUI's will gather and digitize plasma data from the associated diagnostics for further analysis. Progress on the current implementation of the DAQ system will be reported.

  17. Simulation of ionization effects for high-density positron drivers in future plasma wakefield experiments

    SciTech Connect

    Bruhwiler, D.L.; Dimitrov, D.A.; Cary, J.R.; Esarey, E.; Leemans, W.P.

    2003-05-12

    The plasma wakefield accelerator (PWFA) concept has been proposed as a potential energy doubler for present or future electron-positron colliders. Recent particle-in-cell (PIC) simulations have shown that the self-fields of the required electron beam driver can tunnel ionize neutral Li, leading to plasma wake dynamics differing significantly from that of a preionized plasma. It has also been shown, for the case of a preionized plasma, that the plasma wake of a positron driver differs strongly from that of an electron driver. We will present new PIC simulations, using the OOPIC code, showing the effects of tunneling ionization on the plasma wake generated by high-density positron drivers. The results will be compared to previous work on electron drivers with tunneling ionization and positron drivers without ionization. Parameters relevant to the energy doubler and the upcoming E-164x experiment at the Stanford Linear Accelerator Center will be considered.

  18. Registration of ELF waves in rocket-satellite experiment with plasma injection

    NASA Astrophysics Data System (ADS)

    Korobeinikov, V. G.; Oraevskii, V. N.; Ruzhin, Iu. Ia.; Sobolev, Ia. P.; Skomarovskii, V. S.; Chmyrev, V. M.; Namazov, C. A.; Pokhunkov, A. A.; Nesmeianov, V. I.

    1992-12-01

    Two rocket KOMBI-SAMA experiments with plasma injection at height 100-240 km were performed in August 1987 in the region of Brazilian magnetic anomaly (L = 1.25). The launching time of the rocket was determined so that plasma injection was at the time when COSMOS 1809 satellite passed as close as possible to magnetic tube of injection. Caesium plasma jet was produced during not less than 300 s by an electric plasma generator separated from the payload. When the satellite passed the geomagnetic tube intersecting the injection region an enhancement of ELF emission at 140 Hz, 450 Hz by a factor of 2 was registered on board the satellite. An enhancement of energetic particle flux by a factor of 4-5 was registered on board the rocket. Observed ELF emission below 100 Hz is interpreted as the generation of oblique electromagnetic ion-cyclotron waves due to drift plasma instability at the front of the plasma jet.

  19. Recent Results of MJ Plasma-Focus Experiment

    SciTech Connect

    Scholz, M.; Paduch, M.; Tomaszewski, K.; Stepniewski, W.; Bienkowska, B.; Ivanova-Stanik, I.; Karpinski, L.; Miklaszewski, R.; Sadowski, M.J.; Jakubowski, L.; Malinowska, A.; Malinowski, K.; Skladnik-Sadowska, E.; Szydlowski, A.; Kubes, P.; Kravarik, J.; Barvir, P.; Klir, D.; Tsarenko, A.V.; Schmidt, H.

    2006-01-05

    Plasma-Focus (PF) devices, which are based on high-voltage high-current pulse discharges, belong to the non-cylindrical Z-pinches. They produce high-temperature dense magnetized plasma and radiation pulses (of X-rays, electrons, ion beams and fusion protons). The paper reports on studies of intense soft (a few keV) X-ray emission, as performed with a four-frame X-ray camera, and their correlation with time-resolved measurements of current waveforms, neutrons, soft and hard X-rays. Possible mechanisms of the production of fusion neutrons (thermal and non-thermal) were also investigated on the basis of neutron pulses measured at different angels to the electrode outlet axis, and their comparison with time-resolved measurements of the soft and hard X-ray radiation.

  20. Plasma wave experiment for the ISEE-3 mission

    NASA Technical Reports Server (NTRS)

    Scarf, F. L.

    1982-01-01

    Results of analyses of data received from a scientific instrument designed to study solar wind and plasma wave phenomena on the ISEE-3 mission are discussed in two papers prepared for publication. A study of plasma wave levels in and interplanetary magnetic field orientation preceding observations of interplanetary shocks by the satellite infers that quasi-parallel, interplanetary shocks are preceded by foreshocks whose presence is not obviously attributable to scattering of ion beams generated at quasi-perpendicular zones of these interplanetary shocks. Investigations of whistler mode turbulence in the disturbed solar wind resulted in various indirect lines of evidence indicating that these whistler waves are generated propagating at large angles to the local interplanetary field, a fact which helps identify possible free energy sources for their growth.

  1. Drift waves and chaos in a LAPTAG plasma physics experiment

    NASA Astrophysics Data System (ADS)

    Gekelman, Walter; Pribyl, Patrick; Birge-Lee, Henry; Wise, Joe; Katz, Cami; Wolman, Ben; Baker, Bob; Marmie, Ken; Patankar, Vedang; Bridges, Gabriel; Buckley-Bonanno, Samuel; Buckley, Susan; Ge, Andrew; Thomas, Sam

    2016-02-01

    In a project involving an alliance between universities and high schools, a magnetized plasma column with a steep pressure gradient was established in an experimental device. A two-dimensional probe measured fluctuations in the plasma column in a plane transverse to the background magnetic field. Correlation techniques determined that the fluctuations were that of electrostatic drift waves. The time series data were used to generate the Bandt-Pompe entropy and Jensen-Shannon complexity for the data. These quantities, when plotted against one another, revealed that a combination of drift waves and other background fluctuations were a deterministically chaotic system. Our analysis can be used to tell the difference between deterministic chaos and random noise, making it a potentially useful technique in nonlinear dynamics.

  2. Measurements of interactions between waves and energetic ions in basic plasma experiments

    NASA Astrophysics Data System (ADS)

    Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Preiwisch, A.; Zhang, Y.; Zhao, L.; Zhou, S.; Bovet, A.; Fasoli, A.; Furno, I.; Gustafson, K.; Ricci, P.; Carter, T.; Leneman, D.; Tripathi, S. K. P.; Vincena, S.

    2012-12-01

    To measure the transport of fast ions by various types of waves, complementary experiments are conducted in linear and toroidal magnetic fields in the large plasma device and the toroidal plasma experiment. Lithium sources that are immersed in the plasma provide the energetic ions. Spatial scans of collectors measure the transport. Techniques to find the beam and optimize the spatial sensitivity are described. Measurements of Coulomb scattering, resonant interaction with Alfvén waves, and transport by drift-wave and interchange turbulence are summarized.

  3. Rayleigh-Taylor instability in dusty plasma experiment

    SciTech Connect

    Avinash, K.; Sen, A.

    2015-08-15

    The stability of a stratified dust cloud levitated in an anodic plasma is studied in the weakly and strongly coupled dust regimes. It is shown that the cloud is predominantly unstable to a Rayleigh-Taylor (RT) instability driven by a component of the ambient gravity in a direction opposite to the direction of dust density stratification in the cloud. The elasticity of the strongly coupled dust is shown to set a threshold for the RT instability, which is consistent with experimental observations.

  4. Rayleigh-Taylor instability in dusty plasma experiment

    NASA Astrophysics Data System (ADS)

    Avinash, K.; Sen, A.

    2015-08-01

    The stability of a stratified dust cloud levitated in an anodic plasma is studied in the weakly and strongly coupled dust regimes. It is shown that the cloud is predominantly unstable to a Rayleigh-Taylor (RT) instability driven by a component of the ambient gravity in a direction opposite to the direction of dust density stratification in the cloud. The elasticity of the strongly coupled dust is shown to set a threshold for the RT instability, which is consistent with experimental observations.

  5. High Magnetic field generation for laser-plasma experiments

    SciTech Connect

    Pollock, B B; Froula, D H; Davis, P F; Ross, J S; Fulkerson, S; Bower, J; Satariano, J; Price, D; Glenzer, S H

    2006-05-01

    An electromagnetic solenoid was developed to study the effect of magnetic fields on electron thermal transport in laser plasmas. The solenoid, which is driven by a pulsed power system suppling 30 kJ, achieves magnetic fields of 13 T. The field strength was measured on the solenoid axis with a magnetic probe and optical Zeeman splitting. The measurements agree well with analytical estimates. A method for optimizing the solenoid design to achieve magnetic fields exceeding 20 T is presented.

  6. CO2 Laser Beat-Wave Experiment in an Unmagnetized Plasma

    NASA Astrophysics Data System (ADS)

    Liu, Fei; Hwang, David; Horton, Robert; Hong, Sean; Evans, Russell

    2012-10-01

    The ability to remotely generate plasma current in dense plasmas is a basic yet important investigation in experimental plasma physics and fusion energy research. It is even more advantageous if the wave penetration is independent of the electron acceleration process. Plasma current can be generated through beat-wave mixing process by launching two intense electromagnetic waves (φ>>φpe) into plasma. The beat wave formation process can be efficient if the difference frequency of the two pump waves is matched to a local resonant frequency of the medium, i.e. in this case the local plasma frequency. Beat wave can accelerate plasma electrons via quasi-linear Landau process, which has been demonstrated in a low-density plasma using microwaves.footnotetextRogers, J. H. and Hwang, D. Q., Phys. Rev. Lett. v68 p3877 (1992). The CO2 lasers provide the high tunability for the wave-particle interaction experiment at a variety of plasma densities with plasma frequency in THz range. Two sections of Lumonics TEA CO2 lasers have been modified to serve as the two pump wave sources with peak power over 100MW. The development of the tunable CO2 lasers, a high-density plasma target source and diagnostics system will be presented. The initial results of unbalanced beat-wave experiment using one high-power pulsed and one low-power CW CO2 lasers will be presented and discussed using the independent plasma source to control the φpe of the interaction region. This work is supported by U.S. DOE under Contract No. DE-FG02-10ER55083.

  7. PREFACE: 1st Franco-Algerian Workshop on Neutrino Physics

    NASA Astrophysics Data System (ADS)

    Mebarki, N.; Mimouni, J.; Vanucci, F.; Aissaoui, H.

    2015-04-01

    The first Franco-Algerian workshop on neutrino physics was held on 22-23 October 2013 at the University of Mentouri, Constantine, Algeria. It was jointly organized by the Laboratory of Mathematical and Subatomic Physics (LPMS) and the Direction of Scientific Research (DGRSTD) for the Algerian side, and for the French part by the IN2P3, CNRS and CEA IRFU. It is one of a series of international scientific meetings organized every two years by the LPMS at Constantine on high energy physics (theoretical, nuclear physics, classical and quantum cosmology, astrophysics, mathematical physics and quantum computing etc...) to maintain a high quality in scientific research and education at Algerian universities. This specific meeting brought together experts in particle physics, astrophysics and cosmology from France and Algeria. It touched upon several theoretical, phenomenological as well as experimental aspects of the neutrinos. The workshop participants were mostly young researchers from many universities and research institutes in Algeria. The physics of neutrinos is a very active field in particle physics, hence the importance for the High Energy community in Algeria to gain expertise in this ''strategic'' area at the intersection of various topics in theoretical physics and high energy astrophysics (SM physics, CP violation, in general, SNe explosions, baryogenesis...). The neutrino proposed by Pauli back in 1930 as a ''desperate remedy'' to save the law of energy conservation in beta decay had a bright early history. Discovered in 1956 in the Cowan-Reines experiment despite all odds, this elusive particle which enabled us to understand the chiral nature of the weak interactions which later lead to the electro-weak unification finally appears to hold a key role in understanding subatomic physics as well as the structure and structuration of the Universe. It is also, after the discovery of the Higgs particle at the LHC in 2012, the only grey area left today in the

  8. PREFACE: 1st Tensor Polarized Solid Target Workshop

    NASA Astrophysics Data System (ADS)

    2014-10-01

    These are the proceedings of the first Tensor Spin Observables Workshop that was held in March 2014 at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia. The conference was convened to study the physics that can be done with the recently approved E12-13-011 polarized target. A tensor polarized target holds the potential of initiating a new generation of tensor spin physics at Jefferson Lab. Experiments which utilize tensor polarized targets can help clarify how nuclear properties arise from partonic degrees of freedom, provide unique insight into short-range correlations and quark angular momentum, and also help pin down the polarization of the quark sea with a future Electron Ion Collider. This three day workshop was focused on tensor spin observables and the associated tensor target development. The workshop goals were to stimulate progress in the theoretical treatment of polarized spin-1 systems, foster the development of new proposals, and to reach a consensus on the optimal polarized target configuration for the tensor spin program. The workshop was sponsored by the University of New Hampshire, the Jefferson Science Associates, Florida International University, and Jefferson Lab. It was organized by Karl Slifer (chair), Patricia Solvignon, and Elena Long of the University of New Hampshire, Douglas Higinbotham and Christopher Keith of Jefferson Lab, and Misak Sargsian of the Florida International University. These proceedings represent the effort put forth by the community to begin exploring the possibilities that a high-luminosity, high-tensor polarized solid target can offer.

  9. Construction of a solenoid used on a magnetized plasma experiment

    NASA Astrophysics Data System (ADS)

    Klein, S. R.; Manuel, M. J.-E.; Pollock, B. B.; Gillespie, R. S.; Deininger, M.; Kuranz, C. C.; Keiter, P. A.; Drake, R. P.

    2014-11-01

    Creating magnetized jets in the laboratory is relevant to studying young stellar objects, but generating these types of plasmas within the laboratory setting has proven to be challenging. Here, we present the construction of a solenoid designed to produce an axial magnetic field with strengths in the gap of up to 5 T. This novel design was a compact 75 mm × 63 mm × 88 mm, allowing it to be placed in the Titan target chamber. It was robust, surviving over 50 discharges producing fields ≲ 5 T, reaching a peak magnetic field of 12.5 T.

  10. LHCD and ICRF heating experiments in H-mode plasmas on EAST

    SciTech Connect

    Zhang, X. J.; Zhao, Y. P.; Wan, B. N.; Ding, B. J.; Xu, G. S.; Gong, X. Z.; Li, J. G.; Lin, Y.; Wukitch, S.; Taylor, G.; Noterdaeme, J. M.; Braun, F.; Magne, R.; Litaudon, X.; Kumazawa, R.; Kasahara, H.; Collaboration: EAST Team

    2014-02-12

    An ICRF system with power up to 6.0 MW and a LHCD system up to 4MW have been applied for heating and current drive experiments on EAST. Intensive lithium wall coating was intensively used to reduce particle recycling and Hydrogen concentration in Deuterium plasma, which is needed for effective ICRF and LHCD power absorption in high density plasmas. Significant progress has been made with ICRF heating and LHW current drive for realizing the H-mode plasma operation in EAST. In 2010, H-mode was generated and sustained by LHCD alone, where lithium coating and gas puffing launcher mouth were applied to improve the LHCD power coupling and penetration into the core plasmas at high density of H-modes. During the last two experimental campaigns, ICRF Heating experiments were carried out at the fixed frequency of 27MHz, achieving effective ions and electrons heating with the H Minority Heating (H-MH) mode, where electrons are predominantly heated by collisions with high energy minority ions. The H-MH mode gave the best plasma performance, and realized H-mode alone in 2012. Combination of ICRF and LHW power injection generated the H-mode plasmas with various ELMy characteristics. The first successful application of the ICRF Heating in the D (He3) plasma was also achieved. The progress on ICRF heating, LHCD experiments and their application in achieving H-mode operation from last two years will be discussed in this report.

  11. Electrically driving large magnetic Reynolds number flows on the Madison plasma dynamo experiment

    NASA Astrophysics Data System (ADS)

    Weisberg, David; Wallace, John; Peterson, Ethan; Endrezzi, Douglass; Forest, Cary B.; Desangles, Victor

    2015-11-01

    Electrically-driven plasma flows, predicted to excite a large-scale dynamo instability, have been generated in the Madison plasma dynamo experiment (MPDX), at the Wisconsin Plasma Astrophysics Laboratory. Numerical simulations show that certain topologies of these simply-connected flows may be optimal for creating a plasma dynamo and predict critical thresholds as low as Rmcrit =μ0 σLV = 250 . MPDX plasmas are shown to exceed this critical Rm , generating large (L = 1 . 4 m), warm (Te > 10 eV), unmagnetized (MA > 1) plasmas where Rm < 600 . Plasma flow is driven using ten thermally emissive LaB6 cathodes which generate a J × B torque in Helium plasmas. Detailed Mach probe measurements of plasma velocity for two flow topologies will be presented: edge-localized drive using the multi-cusp boundary field, and volumetric drive using an axial Helmholtz field. Radial velocity profiles show that edge-driven flow is established via ion viscosity but is limited by a volumetric neutral drag force (χ ~ 1 / (ντin)), and measurements of velocity shear compare favorably to Braginskii transport theory. Volumetric flow drive is shown to produce stronger velocity shear, and is characterized by the radial potential gradient as determined by global charge balance.

  12. Theory and modelling of helium enrichment in plasma experiments with pump limiters

    SciTech Connect

    Prinja, A.K.; Conn, R.W.

    1984-01-01

    Helium enrichment in the exhaust gas stream flowing from a hydrogen-helium plasma is studied using an analytical theory and Monte Carlo simulations. To provide a sensitive experimental test in a tokamak, an unusual configuration, inverted from traditional designs, is proposed for a pump limiter. The principle can be tested in other plasma devices as well. The theory suggests that for typical plasma edge conditions in a confinement device, namely, n = 10/sup 13/cm/sup -3/ and T/sub i/ = T/sub e/ approx. = 5-30eV, helium enrichment in the neutral gas exhaust stream can be very high, in the range 5 to 7, relative to the helium-hydrogen ratio in the plasma. Such high enrichment factors are achieved by exploiting the difference between the ionization rates of hydrogen and helium and the negligible helium charge exchange rate at these plasma conditions. A limiter arrangement is proposed in which the natural curvature of the toroidal magnetic field is used to isolate, using the plasma itself, the point of plasma neutralization from the location of the gas exhaust. The plasma region then acts to preferentially screen the recycling hydrogen by the processes of ionization and of charge-exchange-induced losses at open boundaries. The theory and analysis suggests that an experiment can provide a sensitive test of modules used to describe the plasma edge and of atomic and surface physics data used in these models.

  13. D-alpha Probe Investigation on the Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    Karama, Jackson; James, Royce; Sherman, Justin; Page, Eric; Schlank, Carter; Stutzman, Brook; Duke-Tenson, Omar; Coast Guard Academy Plasma Laboratory Team

    2013-10-01

    Now that reproducible plasmas have been created on HPX at the Coast Guard Academy Plasma Laboratory (CGAPL) we are starting to set up a spectral probes to help verify plasma mode transitions to the W-mode. These optical probes will utilize movable filters, ccd cameras and diodes, to gather data at selected spectral frequency bands. Data collected will be used to investigate the plasma's structure and behavior during experiments. The spectral probes will take advantage of HPX's magnetic fields to define and measure the plasma's radiation temp as a function of time. A d-alpha filter will allow for the collection of neutral density fluctuations for different plasma behaviors. In d-alpha mode, the probe may also provide some information on the internal plasma structure and perhaps reveal some global plasma interactions. The spectral probe will add to HPX's data collection capabilities and be used in conjunction with the particle probes, and Thomson Scattering device to create a robust picture of the internal and external plasma parameters on HPX. Progress on the construction of the probe will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY12.

  14. Laser experiments to simulate coronal mass ejection driven magnetospheres and astrophysical plasma winds on compact magnetized stars

    NASA Astrophysics Data System (ADS)

    Horton, W.; Ditmire, T.; Zakharov, Yu. P.

    2010-06-01

    Laboratory experiments using a plasma wind generated by laser-target interaction are proposed to investigate the creation of a shock in front of the magnetosphere and the dynamo mechanism for creating plasma currents and voltages. Preliminary experiments are shown where measurements of the electron density gradients surrounding the obstacles are recorded to infer the plasma winds. The proposed experiments are relevant to understanding the electron acceleration mechanisms taking place in shock-driven magnetic dipole confined plasmas surrounding compact magnetized stars and planets. Exploratory experiments have been published [P. Brady, T. Ditmire, W. Horton, et al., Phys. Plasmas 16, 043112 (2009)] with the one Joule Yoga laser and centimeter sized permanent magnets.

  15. Synergy Between Experiments and Simulations in Laser and Beam-Driven Plasma Acceleration and Light Sources

    NASA Astrophysics Data System (ADS)

    Mori, Warren B.

    2015-11-01

    Computer simulations have been an integral part of plasma physics research since the early 1960s. Initially, they provided the ability to confirm and test linear and nonlinear theories in one-dimension. As simulation capabilities and computational power improved, then simulations were also used to test new ideas and applications of plasmas in multi-dimensions. As progress continued, simulations were also used to model experiments. Today computer simulations of plasmas are ubiquitously used to test new theories, understand complicated nonlinear phenomenon, model the full temporal and spatial scale of experiments, simulate parameters beyond the reach of current experiments, and test the performance of new devices before large capital expenditures are made to build them. In this talk I review the progress in simulations in a particular area of plasma physics: plasma based acceleration (PBA). In PBA a short laser pulse or particle beam propagates through long regions of plasma creating plasma wave wakefields on which electrons or positrons surf to high energies. In some cases the wakefields are highly nonlinear, involve three-dimensional effects, and the trajectories of plasma particles cross making it essential that fully kinetic and three-dimensional models are used. I will show how particle-in-cell (PIC) simulations were initially used to propose the basic idea of PBA in one dimension. I will review some of the dramatic progress in the experimental demonstration of PBA and show how this progress was dramatically helped by a synergy between experiments and full-scale multi-dimensional PIC simulations. This will include a review of how the capability of PIC simulation tools has improved. I will also touch on some recent progress on improvements to PIC simulations of PBA and discuss how these improvements may push the synergy further towards real time steering of experiments and start to end modeling of key components of a future linear collider or XFEL based on PBA

  16. Review of D-T Experiments Relevant to Burning Plasma Issues

    SciTech Connect

    R.J. Hawryluk

    2001-12-21

    Progress in the performance of tokamak devices has enabled not only the production of significant bursts of fusion energy from deuterium-tritium (D-T) plasmas in the Tokamak Fusion Test Reactor (TFTR) and the Joint European Torus (JET) but, more importantly, the initial study of the physics of burning magnetically confined plasmas. The TFTR and JET, in conjunction with the worldwide fusion effort, have studied a broad range of topics including magnetohydrodynamic stability, transport, wave-particle interactions, the confinement of energetic particles, and plasma boundary interactions. The D-T experiments differ in three principal ways from previous experiments: isotope effects associated with the use of deuterium-tritium fuel, the presence of fusion-generated alpha particles, and technology issues associated with tritium handling and increased activation. The effect of deuterium-tritium fuel and the presence of alpha particles is reviewed and placed in the perspective of the much large r worldwide database using deuterium fuel and theoretical understanding. Both devices have contributed substantially to addressing the scientific and technical issues associated with burning plasmas. However, future burning plasma experiments will operate with larger ratios of alpha heating power to auxiliary power and will be able to access additional alpha-particle physics issues. The scientific opportunities for extending our understanding of burning plasmas beyond that provided by current experiments is described.

  17. Theory and experiments characterizing hypervelocity impact plasmas on biased spacecraft materials

    NASA Astrophysics Data System (ADS)

    Lee, Nicolas; Close, Sigrid; Goel, Ashish; Lauben, David; Linscott, Ivan; Johnson, Theresa; Strauss, David; Bugiel, Sebastian; Mocker, Anna; Srama, Ralf

    2013-03-01

    Space weather including solar activity and background plasma sets up spacecraft conditions that can magnify the threat from hypervelocity impacts. Hypervelocity impactors include both meteoroids, traveling between 11 and 72 km/s, and orbital debris, with typical impact speeds of 10 km/s. When an impactor encounters a spacecraft, its kinetic energy is converted over a very short timescale into energy of vaporization and ionization, resulting in a small, dense plasma. This plasma can produce radio frequency (RF) emission, causing electrical anomalies within the spacecraft. In order to study this phenomenon, we conducted ground-based experiments to study hypervelocity impact plasmas using a Van de Graaff dust accelerator. Iron projectiles ranging from 10-16 g to 10-11 g were fired at speeds of up to 70 km/s into a variety of target materials under a range of surface charging conditions representative of space weather effects. Impact plasmas associated with bare metal targets as well as spacecraft materials were studied. Plasma expansion models were developed to determine the composition and temperature of the impact plasma, shedding light on the plasma dynamics that can lead to spacecraft electrical anomalies. The dependence of these plasma properties on target material, impact speed, and surface charge was analyzed. Our work includes three major results. First, the initial temperature of the impact plasma is at least an order of magnitude lower than previously reported, providing conditions more favorable for sustained RF emission. Second, the composition of impact plasmas from glass targets, unlike that of impact plasmas from tungsten, has low dependence on impact speed, indicating a charge production mechanism that is significant down to orbital debris speeds. Finally, negative ion formation has a strong dependence on target material. These new results can inform the design and operation of spacecraft in order to mitigate future impact-related space weather

  18. Laboratory Experiments on Propagating Plasma Bubbles into Vacuum, Vacuum Magnetic Field, and Background Plasmas

    NASA Astrophysics Data System (ADS)

    Lynn, Alan G.; Zhang, Yue; Gilmore, Mark; Hsu, Scott

    2014-10-01

    We discuss the dynamics of plasma ``bubbles'' as they propagate through a variety of background media. These bubbles are formed by a pulsed coaxial gun with an externally applied magnetic field. Bubble parameters are typically ne ~1020 m-3, Te ~ 5 - 10 eV, and Ti ~ 10 - 15 eV. The structure of the bubbles can range from unmagnetized jet-like structures to spheromak-like structures with complex magnetic flux surfaces. Some of the background media the bubbles interact with are vacuum, vacuum with magnetic field, and other magnetized plasmas. These bubbles exhibit different qualitative behavior depending on coaxial gun parameters such as gas species, gun current, and gun bias magnetic field. Their behavior also depends on the parameters of the background they propagate through. Multi-frame fast camera imaging and magnetic probe data are used to characterize the bubble evolution under various conditions.

  19. Highly efficient -1st-order reflection in Littrow mounted dielectric double-groove grating

    NASA Astrophysics Data System (ADS)

    Ito, Kota; Iizuka, Hideo

    2013-06-01

    We show that in a silicon double-groove grating with two different groove widths per period attached on top of a semi-infinite SiO2 substrate, almost 100% reflectivity is achieved for the -1st-order reflection with an incident angle of 60° in the Littrow mounting condition. The modal analysis reveals that modes propagating in the upward and downward directions have nearly the same amplitudes at resonance. They are added constructively for the -1st-order reflection and destructively for the 0th-order reflection and the -1st-order and 0th-order transmission. The asymmetric structure with a dielectric material poses a unique feature as a four port device.

  20. Flow dynamics and magnetic induction in the von-Kármán plasma experiment

    NASA Astrophysics Data System (ADS)

    Plihon, N.; Bousselin, G.; Palermo, F.; Morales, J.; Bos, W. J. T.; Godeferd, F.; Bourgoin, M.; Pinton, J.-F.; Moulin, M.; Aanesland, A.

    2015-01-01

    The von-Kármán plasma experiment is a novel versatile experimental device designed to explore the dynamics of basic magnetic induction processes and the dynamics of flows driven in weakly magnetized plasmas. A high-density plasma column (1016-1019 particles. m-3) is created by two radio-frequency plasma sources located at each end of a 1 m long linear device. Flows are driven through J × B azimuthal torques created from independently controlled emissive cathodes. The device has been designed such that magnetic induction processes and turbulent plasma dynamics can be studied from a variety of time-averaged axisymmetric flows in a cylinder. MHD simulations implementing volume-penalization support the experimental development to design the most efficient flow-driving schemes and understand the flow dynamics. Preliminary experimental results show that a rotating motion of up to nearly 1 km/s is controlled by the J × B azimuthal torque.

  1. Plasma potential control: initial results from tandem mirror experiment-upgrade

    SciTech Connect

    Hopper, E.B. Jr.

    1984-02-28

    Initial plasma potential control experiments used plates in the end fan, insulated from the end walls of TMX-U, which mapped along field lines to the plasma core (r/sub c/ less than or equal to 12.9 cm). Measurements in which these plates are shorted to ground during plugging demonstrate that floating the plates increases the buildup rate of the central cell plasma, steepens the core density profile, and affects the plasma throughout the entire cross section. Floating the plates decreases the ion radial transport rate in the core by a factor of at least 1.5. Because of these encouraging results, in the next series of experiments more plates will be added, extending to a larger radius (r/sub c/ less than or equal to 19.4 cm).

  2. Minimally Invasive Arthrodesis of 1st Metatarsophalangeal Joint for Hallux Rigidus.

    PubMed

    Sott, A H

    2016-09-01

    First metatarsophalangeal joint arthrodesis plays a significant role in the management of symptomatic hallux rigidus/osteoarthritis of the 1st metatarsophalangeal joint. Several open and few percutaneous techniques have been described in the literature. This article describes and discusses a percutaneous technique that has been successfully used to achieve a pain-free stable and functional 1st metatarsophalangeal joint. All aspects of surgical indication and operative technique and details of patient-reported outcomes are presented with a referenced discussion. PMID:27524706

  3. Laboratory plasma interactions experiments: Results and implications to future space systems

    NASA Technical Reports Server (NTRS)

    Leung, Philip

    1986-01-01

    The experimental results discussed show the significance of the effects caused by spacecraft plasma interactions, in particular the generation of Electromagnetic Interference. As the experimental results show, the magnitude of the adverse effects induced by Plasma Interactions (PI) will be more significant for spacecraft of the next century. Therefore, research is needed to control possible adverse effects. Several techniques to control the selected PI effects are discussed. Tests, in the form of flight experiments, are needed to validate these proposed ideas.

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

    SciTech Connect

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

    1986-08-29

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

  5. Plasma waves produced by the xenon ion beam experiment on the Porcupine sounding rocket

    NASA Technical Reports Server (NTRS)

    Kintner, P. M.; Kelley, M.

    1982-01-01

    The production of electrostatic ion cyclotron waves by a perpendicular ion beam in the F-region ionosphere is described. The ion beam experiment was part of the Porcupine program and produced electrostatic hydrogen cyclotron waves just above harmonics of the hydrogen cyclotron frequency. The plasma process may be thought of as a magnetized background ionosphere through which an unmagnetized beam is flowing. The dispersion equation for this hypothesis is constructed and solved. Preliminary solutions agree well with the observed plasma waves.

  6. Material Surface Characteristics and Plasma Performance in the Lithium Tokamak Experiment

    NASA Astrophysics Data System (ADS)

    Lucia, Matthew James

    The performance of a tokamak plasma and the characteristics of the surrounding plasma facing component (PFC) material surfaces strongly influence each other. Despite this relationship, tokamak plasma physics has historically been studied more thoroughly than PFC surface physics. The disparity is particularly evident in lithium PFC research: decades of experiments have examined the effect of lithium PFCs on plasma performance, but the understanding of the lithium surface itself is much less complete. This latter information is critical to identifying the mechanisms by which lithium PFCs affect plasma performance. This research focused on such plasma-surface interactions in the Lithium Tokamak Experiment (LTX), a spherical torus designed to accommodate solid or liquid lithium as the primary PFC. Surface analysis was accomplished via the novel Materials Analysis and Particle Probe (MAPP) diagnostic system. In a series of experiments on LTX, the MAPP x-ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS) capabilities were used for in vacuo interrogation of PFC samples. This represented the first application of XPS and TDS for in situ surface analysis of tokamak PFCs. Surface analysis indicated that the thin (dLi ˜ 100nm) evaporative lithium PFC coatings in LTX were converted to Li2O due to oxidizing agents in both the residual vacuum and the PFC substrate. Conversion was rapid and nearly independent of PFC temperature, forming a majority Li2O surface within minutes and an entirely Li2O surface within hours. However, Li2O PFCs were still capable of retaining hydrogen and sequestering impurities until the Li2 O was further oxidized to LiOH, a process that took weeks. For hydrogen retention, Li2O PFCs retained H+ from LTX plasma discharges, but no LiH formation was observed. Instead, results implied that H+ was only weakly-bound, such that it almost completely outgassed as H 2 within minutes. For impurity sequestration, LTX plasma performance

  7. Solvent/detergent-treated plasma: a tale of 30 years of experience.

    PubMed

    Liumbruno, Giancarlo Maria; Marano, Giuseppe; Grazzini, Gioia; Capuzzo, Enrico; Franchini, Massimo

    2015-06-01

    Solvent/detergent-treated plasma was licensed >30 years ago. It has several specific characteristics, the most important being the standardized content of clotting factors, the lack of antibodies implicated in transfusion-related acute lung injury pathogenesis and the very high level of safety against transfusion-related viral infections. Since 1992, many clinical studies have confirmed its safety and efficacy in a wide range of congenital and acquired bleeding disorders. After a brief analysis of the pharmaceutical characteristics of solvent/detergent plasma, this review will focus on the clinical experience with this virus-inactivated plasma.

  8. Experimental observations and model calculations of impurity radiation in a plasma gun compact torus experiment

    SciTech Connect

    Goldenbaum, G.C.; Granneman, E.H.A.; Hartman, C.W.; Prono, D.S.; Taska, J.; Turner, W.C.

    1982-08-10

    Several types of radiation measurements were performed on the Beta II compact forms experiment. Among these are time integrated spectra ranging in wavelength from the vuv to the uv, time resolved bolometer measurements of radiation from the x-ray to the infrared, and time and wavelength resolved measurements of certain spectral lines. It is difficult to relate any one of these measurements to plasma parameters of interest such as temperature, density, or impurity content. In this report we compare the results of these, and other measurements with two simple models of the power balance in the plasma in order to estimate the effect of carbon and oxygen impurities on plasma lifetime.

  9. Plasma-Jet-Driven Magneto-Inertial Fusion (PJMIF): Physics and Design for a Plasma Liner Formation Experiment

    NASA Astrophysics Data System (ADS)

    Hsu, Scott; Cassibry, Jason; Witherspoon, F. Douglas

    2014-10-01

    Spherically imploding plasma liners are a potential standoff compression driver for magneto-inertial fusion, which is a hybrid of and operates in an intermediate density between those of magnetic and inertial fusion. We propose to use an array of merging supersonic plasma jets to form a spherically imploding plasma liner. The jets are to be formed by pulsed coaxial guns with contoured electrodes that are placed sufficiently far from the location of target compression such that no hardware is repetitively destroyed. As such, the repetition rate can be higher (e.g., 1 Hz) and ultimately the power-plant economics can be more attractive than most other MIF approaches. During the R&D phase, a high experimental shot rate at reasonably low cost (e.g., < 1 k/shot) may be achieved with excellent diagnostic access, thus enabling a rapid learning rate. After some background on PJMIF and its prospects for reactor-relevant energy gain, this poster describes the physics objectives and design of a proposed 60-gun plasma-liner-formation experiment, which will provide experimental data on: (i) scaling of peak liner ram pressure versus initial jet parameters, (ii) liner non-uniformity characterization and control, and (iii) control of liner profiles for eventual gain optimization.

  10. Proposal for secondary enclosure setup for experiments to expose plasma facing materials to tritiated plasma in VISIONI

    SciTech Connect

    Broeckx, W.E.K.; Dylst, K.; Bornea, A.; Zamfirache, M.

    2015-03-15

    VISIONI is an equipment at SCK-CEN that allows the exposure of candidate plasma facing materials to tritium - deuterium plasmas at ITER first wall conditions. VISIONI itself, being a vacuum setup, acts as primary confinement. To protect operators against exposure to a tritiated atmosphere VISIONI must be placed in a secondary confinement. The current Tritium lab at SCK-CEN has a walk-in process cell which can be used to enclose the plasma chamber and diagnostics of the VISIONI setup, which have a limited tritium inventory. This allows easy accessibility to the setup in a well-ventilated environment. Routine operations should be conducted from outside the process cell and maintenance operations can be conducted from within the process cell with proper protections. The tritium storage and supply can be enclosed in a glove box with a dedicated air detritiation system which is activated during an experiment or in case of an incident. The detritiation system will oxidize tritium and capture it on molecular sieves. By using this confinement approach it is possible to expose materials to a tritiated plasma while maintaining good accessibility of the VISIONI setup. This paper describes the proposed confinement system and compares it to the most common approach where the entire system is enclosed into one large glovebox.

  11. Interaction of Fast Ions with Global Plasma Modes in the C-2 Field Reversed Configuration Experiment

    NASA Astrophysics Data System (ADS)

    Smirnov, Artem; Dettrick, Sean; Clary, Ryan; Korepanov, Sergey; Thompson, Matthew; Trask, Erik; Tuszewski, Michel

    2012-10-01

    A high-confinement operating regime [1] with plasma lifetimes significantly exceeding past empirical scaling laws was recently obtained by combining plasma gun edge biasing and tangential Neutral Beam Injection (NBI) in the C-2 field-reversed configuration (FRC) experiment [2, 3]. We present experimental and computational results on the interaction of fast ions with the n=2 rotational and n=1 wobble modes in the C-2 FRC. It is found that the n=2 mode is similar to quadrupole magnetic fields in its detrimental effect on the fast ion transport due to symmetry breaking. The plasma gun generates an inward radial electric field, thus stabilizing the n=2 rotational instability without applying the quadrupole magnetic fields. The resultant FRCs are nearly axisymmetric, which enables fast ion confinement. The NBI further suppresses the n=2 mode, improves the plasma confinement characteristics, and increases the plasma configuration lifetime [4]. The n=1 wobble mode has relatively little effect on the fast ion transport, likely due to the approximate axisymmetry about the displaced plasma column. [4pt] [1] M. Tuszewski et al., Phys. Rev. Lett. 108, 255008 (2012).[0pt] [2] M. Binderbauer et al., Phys. Rev. Lett. 105, 045003 (2010).[0pt] [3] H.Y. Guo et al., Phys. Plasmas 18, 056110 (2011).[0pt] [4] M. Tuszewski et al., Phys. Plasmas 19, 056108 (2012)

  12. Production of low-density plasma by coaxially segmented rf discharge for void-free dusty cloud in microgravity experiments

    SciTech Connect

    Suzukawa, Wataru; Ikada, Reijiro; Tanaka, Yasuhiro; Iizuka, Satoru

    2006-03-20

    A technique is presented for producing a low density plasma by introducing a coaxially segmented parallel-plate radio-frequency discharge for void-free dusty-cloud formation. Main plasma for the dusty plasma experiment is produced in a central core part of the parallel-plate discharge, while a plasma for igniting the core plasma discharge is produced in the periphery region surrounding the core plasma. The core plasma density can be markedly decreased to reduce the ion drag force, which is important for a formation of void-free dusty cloud under microgravity.

  13. PREFACE: 1st Conference on Light and Particle Beams in Materials Science 2013 (LPBMS2013)

    NASA Astrophysics Data System (ADS)

    Kumai, Reiji; Murakami, Youichi

    2014-04-01

    From 29-31 August 2013, the 1st International Conference on Light and Particle Beams in Materials Science, LPBMS 2013, took place in the Tsukuba International Congress Center in the city of Tsukuba, Japan. The conference was a continuation of the international series Synchrotron Radiation in Materials Science (SRMS), which started in 1994. The last one, SRMS-7, was held in Oxford UK 11-14 July 2010, where the International Advisory Committee (IAC) recommended the conference be enlarged to incorporate Materials Research from Neutron, Muon, and Slow Positron Sources, as well as the science emerging from Synchrotron Light Sources. The conference brought together contributions from academics and industrial researchers with a diverse background and experience from the physics, chemistry and engineering communities. The topics covered in the LPBMS2013 include strongly correlated electron systems, magnetism and magnetic materials, soft matter, interface and surface defects, catalysts, biomaterials, and ceramics. In the 3-day scientific program, the conference consisted of 9 plenary talks, 33 invited talks, 20 oral presentations, and 126 poster presentations. We are pleased to publish the proceedings of the LPBMS2013 in this volume of Journal of Physics: Conference Series. This volume contains 58 papers representing the work that was presented and discussed at the conference. We hope that this volume will promote further development of this interdisciplinary materials research emerging from synchrotron light, neutron, muon, and slow positron sciences. Finally, we would like to thank the International Advisory Committee (Chair: Professor G N Greaves), sponsors, all the participants and contributors for making possible this international meeting of researchers. Reiji Kumai & Youichi Murakami Conference photograph Details of the program and organizing committees are available in the pdf

  14. The AMY experiment: Microwave emission from air shower plasmas

    NASA Astrophysics Data System (ADS)

    Alvarez-Muñiz, J.; Blanco, M.; Boháčová, M.; Buonomo, B.; Cataldi, G.; Coluccia, M. R.; Creti, P.; De Mitri, I.; Di Giulio, C.; Facal San Luis, P.; Foggetta, L.; Gaïor, R.; Garcia-Fernandez, D.; Iarlori, M.; Le Coz, S.; Letessier-Selvon, A.; Louedec, K.; Maris, I. C.; Martello, D.; Mazzitelli, G.; Monasor, M.; Perrone, L.; Petrera, S.; Privitera, P.; Rizi, V.; Rodriguez Fernandez, G.; Salamida, F.; Salina, G.; Settimo, M.; Valente, P.; Vazquez, J. R.; Verzi, V.; Williams, C.

    2016-07-01

    You The Air Microwave Yield (AMY) experiment investigate the molecular bremsstrahlung radiation emitted in the GHz frequency range from an electron beam induced air-shower. The measurements have been performed at the Beam Test Facility (BTF) of Frascati INFN National Laboratories with a 510 MeV electron beam in a wide frequency range between 1 and 20 GHz. We present the apparatus and the results of the tests performed.

  15. Laser-plasma interaction in the context of inertial fusion: experiments and modeling

    NASA Astrophysics Data System (ADS)

    Labaune, C.; Lewis, K.; Bandulet, H.; Depierreux, S.; Hüller, S.; Masson-Laborde, P. E.; Pesme, D.; Loiseau, P.

    2007-08-01

    Many nonlinear processes may affect the laser beam propagation and the laser energy deposition in the underdense plasma surrounding the pellet. These processes, associated with anomalous and nonlinear absorption mechanisms, are fundamental issues in the context of Inertial Confinement Fusion. The work presented in this article refers to laser-plasma interaction experiments which were conducted under well-controlled conditions, and to their theoretical and numerical modeling. Thanks to important diagnostics improvements, the plasma and laser parameters were sufficiently characterized in these experiments to make it possible to carry out numerical simulations modeling the laser plasma interaction in which the hydrodynamics conditions were very close to the experimental ones. Two sets of experiments were carried out with the LULI 2000 and the six beam LULI laser facilities. In the first series of experiments, the interaction between two single hot spots was studied as a function of their distance, intensity and light polarization. In the second series, the intensity distribution of stimulated Brillouin scattering (SBS) inside the plasma was studied by means of a new temporally resolved imaging system. Two-dimensional (2D) simulations were carried out with our code Harmony2D in order to model these experiments. For both series of experiments, the numerical results show a very good agreement with the experimental ones for what concerns the main SBS features, namely the spatial and temporal behavior of the SBS-driven acoustic waves, as well as the average SBS reflectivities. Thus, these well diagnosed experiments, carried out with well defined conditions, make it possible to benchmark our theoretical and numerical modelings and, hence, to improve our predictive capabilities for future experiments.

  16. Artificial plasma experiments. Chemical release observations associated with the CRRES program

    NASA Technical Reports Server (NTRS)

    Mende, Stephen B.

    1994-01-01

    This report submitted is the final report and covers work performed under the contract for the period Apr. 12, 1985 - Dec. 23, 1993. The CRRES program investigated earth plasma environment by active experiments in which metal vapors were injected into the upper atmosphere and magnetosphere. The vapor clouds perturb the ambient ionospheric / magnetospheric environment and the effects could be monitored by passive observing instruments. Our part of the CRRES program, the Artificial Plasma Experiment program, was a ground based and aircraft based investigation to observe artificial chemical releases by optical techniques.

  17. 130. Post1911. Photograph labeled, 'SEASON 1913. CAPTAIN, 1st MATE, SUPT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    130. Post-1911. Photograph labeled, 'SEASON 1913. CAPTAIN, 1st MATE, SUPT AND STOREKEEPER, A.P. ASS'N CANNERY, SHIP STAR OF ALASKA.' View forward from mizzenmast, post side. - Ship BALCLUTHA, 2905 Hyde Street Pier, San Francisco, San Francisco County, CA

  18. 47. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    47. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st St. S., Columbus, Ms. Latching mechanism, E end of turn span, viewed from W. Sarcone Photography, Columbus, Ms. Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  19. 42. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st St. S., Columbus, Ms. Copy of postcard ca. 1900. Copy owned and made by Jack Donnell, Columbus, Ms. Shows two-span steel truss, built by Phoenix Bridge Co. in 1878. Negative copied by: Sarcone Photography, Columbus, Ms. Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  20. 48. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    48. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st St. S., Columbus, Ms Latching mechanism, E end of turn span, view from N. Sarcone Photography, Columbus, MS. Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  1. 49. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    49. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st St. S., Columbus, Ms. Top of pier and underside of w end of turn span. Sarcone Photography, Columbus, Ms. Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  2. The Student View of 1st Year Laboratory Work in the Biosciences--Score Gamma?

    ERIC Educational Resources Information Center

    Collis, Mike; Gibson, Alan; Hughes, Ian; Sayers, Gill; Todd, Martin

    2008-01-01

    Students registered on 1st year bioscience courses in 9 universities were surveyed for their views on the laboratory classes they were taking. Returns were obtained from 695 (70%). Student views were varied, some viewing particular features of laboratory classes as "good" while others viewed the same features as "bad". Students identified as the…

  3. How Many Attempts Until Success in Some Core 1st. Year Disciplines?

    ERIC Educational Resources Information Center

    Fernandes, Graça Leão; Andrade e Silva, João; Lopes, Margarida Chagas

    2012-01-01

    Due to a general development in education brought about by democracy, Portugal has witnessed tremendous development in Higher Education (HE) since the beginning of the 1980s. Nevertheless, the percentage of graduates among the Portuguese population still ranks far below most European countries. This is why academic performance in HE 1st cycle…

  4. 24. OVERALL OF 1st FLOOR OF MILL NO. 1. PALLETS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. OVERALL OF 1st FLOOR OF MILL NO. 1. PALLETS HELD CLOTH IN STORAGE IN LATE 20th CENTURY. IRON POSTS IN LEFT DISTANCE FRONTED CLOTH BINS. HISTORIAN LEEANN LANDS IN BACKGROUND WITH LIGHT. - Prattville Manufacturing Company, Number One, 242 South Court Street, Prattville, Autauga County, AL

  5. 77 FR 22574 - Filing Dates for the Washington Special Election In the 1st Congressional District

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-16

    ... From the Federal Register Online via the Government Publishing Office FEDERAL ELECTION COMMISSION Filing Dates for the Washington Special Election In the 1st Congressional District AGENCY: Federal Election Commission. ACTION: Notice of filing dates for special election. SUMMARY: Washington has...

  6. The Course of Psychological Disorders in the 1st Year After Cancer Diagnosis

    ERIC Educational Resources Information Center

    Kangas, Maria; Henry, Jane L.; Bryant, Richard A.

    2005-01-01

    This study investigated the relationship between acute stress disorder (ASD) and posttraumatic stress disorder (PTSD) and comorbid anxiety, depressive, and substance use disorders over the first 12-month period following a cancer diagnosis. Individuals recently diagnosed with 1st onset head and neck or lung malignancy were assessed for ASD within…

  7. Perceptual Narrowing of Linguistic Sign Occurs in the 1st Year of Life

    ERIC Educational Resources Information Center

    Palmer, Stephanie Baker; Fais, Laurel; Golinkoff, Roberta Michnick; Werker, Janet F.

    2012-01-01

    Over their 1st year of life, infants' "universal" perception of the sounds of language narrows to encompass only those contrasts made in their native language (J. F. Werker & R. C. Tees, 1984). This research tested 40 infants in an eyetracking paradigm and showed that this pattern also holds for infants exposed to seen language--American Sign…

  8. Requirement of copper for 1st-log growth of the yeast Saccharomyces cerevisiae

    SciTech Connect

    Como, S.A.; Valerio, V.; Nickless, S.; Connelly, J.L.

    1986-05-01

    Routine evaluation of the role of copper (Cu) in the growth of various mutants of the yeast Saccharomyces Cerevisiae disclosed an unexpected effect of Cu on the fermentative first-log growth. The authors subsequent studies are attempting to ascertain the nature and significance of this observation. Cells are grown on glucose in a supplemented minimal media at 29/sup 0/C for 48-72 hrs. using New Brunswick incubator shaking at 200 rpm. Cu concentration was varied by addition of Cu salts or bathocuproine disulfonate (BC), a highly specific Cu chelator. Samples were removed periodically from flasks and dry weights were determined. Growth curve plots of normal yeasts grown in the presence of 1mM to 38mM Cu showed little variation in the expected 1st log; diauxi; 2nd log; stationary phase picture. However, in the presence of BC growth rate in the 1st log was significantly slowed and as expected 2nd log growth was essentially stopped. The low 1st log growth rate could be titrated to normal (+Cu) levels by increments of added Cu but not by added iron. The effect was not seen when Rho-minus strains were used nor when growth was followed under anaerobic conditions. Results to date implicate a mitochondrial protein, oxygen and copper in the 1st log growth of S Cerevisiae. The character of the protein agent and the possible contribution of cytochrome oxidase activity to the lst log growth are being evaluated.

  9. Analysis of Capillary Guided Laser Plasma Accelerator Experiments at LBNL

    SciTech Connect

    Nakamura, K.; Esarey, E.; Leemans, W. P.; Gonsalves, A. J.; Panasenko, D.; Toth, Cs.; Geddes, C. G. R.; Schroeder, C. B.; Lin, C.

    2009-01-22

    Laser wakefield acceleration experiments were carried out by using a hydrogen-filled capillary discharge waveguide. For a 15 mm long, 200 {mu}m diameter capillary, quasi-monoenergetic e-beams up to 300 MeV were observed. By de-tuning discharge delay from optimum guiding performance, self-trapping was found to be stabilized. For a 33 mm long, 300 {mu}m capillary, a parameter regime with high energy electron beams, up to 1 GeV, was found. In this regime, the electron beam peak energy was correlated with the amount of trapped electrons.

  10. Analysis of Capillary Guided Laser Plasma Accelerator Experiments at LBNL

    SciTech Connect

    Advanced Light Source; Nakamura, Kei; Gonsalves, Anthony; Panasenko, Dmitriy; Lin, Chen; Toth, Csaba; Geddes, Cameron; Schroeder, Carl; Esarey, Eric; Leemans, Wim

    2008-09-29

    Laser wakefield acceleration experiments were carried out by using a hydrogen-filledcapillary discharge waveguide. For a 15 mm long, 200 mu m diameter capillary, quasi-monoenergetic e-beams up to 300 MeV were observed. By de-tuning discharge delay from optimum guiding performance, self-trapping was found to be stabilized. For a 33 mm long, 300 mu m capillary, a parameter regime with high energy electron beams, up to 1 GeV, was found. In this regime, the electron beam peak energy was correlated with the amount of trapped electrons.

  11. Rotating plasma disks in dense Z-pinch experiments

    SciTech Connect

    Bennett, M. J. E-mail: s.lebedev@imperial.ac.uk; Lebedev, S. V. E-mail: s.lebedev@imperial.ac.uk; Suttle, L.; Burdiak, G.; Suzuki-Vidal, F.; Hare, J.; Swadling, G.; Patankar, S.; Bocchi, M.; Chittenden, J. P.; Smith, R.; Hall, G. N.; Frank, A.; Blackman, E.; Drake, R. P.; Ciardi, A.

    2014-12-15

    We present data from the first z-pinch experiments aiming to simulate aspects of accretion disk physics in the laboratory. Using off axis ablation flows from a wire array z-pinch we demonstrate the formation of a hollow disk structure that rotates at 60 kms{sup −1} for 150 ns. By analysing the Thomson scattered spectrum we make estimates for the ion and electron temperatures as T{sub i} ∼ 60 eV and ZT{sub e} ∼ 150 to 200 eV.

  12. The plasma dynamics of hypersonic spacecraft: Applications of laboratory simulations and active in situ experiments

    NASA Technical Reports Server (NTRS)

    Stone, N. H.; Samir, Uri

    1986-01-01

    Attempts to gain an understanding of spacecraft plasma dynamics via experimental investigation of the interaction between artificially synthesized, collisionless, flowing plasmas and laboratory test bodies date back to the early 1960's. In the past 25 years, a number of researchers have succeeded in simulating certain limited aspects of the complex spacecraft-space plasma interaction reasonably well. Theoretical treatments have also provided limited models of the phenomena. Several active experiments were recently conducted from the space shuttle that specifically attempted to observe the Orbiter-ionospheric interaction. These experiments have contributed greatly to an appreciation for the complexity of spacecraft-space plasma interaction but, so far, have answered few questions. Therefore, even though the plasma dynamics of hypersonic spacecraft is fundamental to space technology, it remains largely an open issue. A brief overview is provided of the primary results from previous ground-based experimental investigations and the preliminary results of investigations conducted on the STS-3 and Spacelab 2 missions. In addition, several, as yet unexplained, aspects of the spacecraft-space plasma interaction are suggested for future research.

  13. Plasma stabilization experiment. Final report, 1 October 1979-30 April 1980

    SciTech Connect

    Sziklas, E. A.; Fader, W. J.; Jong, R. A.; Stufflebeam, J. H.

    1980-07-01

    The Plasma Stabilization Experiment is an effort to enhance stability in a mirror-confined plasma by trapping cold ions with rf fields applied near the mirror throats. Nagoya Type III antennas, coupled to a 60 kW rf power supply are mounted in the throats of the UTRC baseball magnet. An external washer gun provides a source of plasma for both streaming and confined plasma tests. Results show a strong stoppering effect on streaming plasmas and a marginal effect on confined plasmas. Theoretical calculations provide an explanation for the experimental observations. The field generates a ponderomotive force acting on the electrons. The resultant improvement in electron confinement changes the ambipolar potential and inhibits the flow of ions through the mirror throat. Criteria are derived for the validity of this trapping concept. The requisite field strengths are significantly lower than those required to trap ions directly. Scaling laws are developed for application of cold ion trapping to large mirror devices containing dense plasmas. The use of slow-wave antenna structures operated at frequencies above the lower hybrid frequency is recommended for these applications.

  14. Updates on the Optical Emission Spectroscopy and Thomson Scattering Investigations on the Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    Duke-Tinson, Omar; Karama, Jackson; Azzari, Phillip; Royce, James; Page, Eric; Schlank, Carter; Sherman, Justin; Stutzman, Brooke; Zuniga, Jonathan

    2014-10-01

    HPX at the Coast Guard Academy Plasma Laboratory (CGAPL) have set up spectral probes to verify plasma mode transitions to the W-mode. These optical probes utilize movable filters, and ccd cameras to gather data at selected spectral frequency bands. Raw data collected will be used to measure the plasma's relative density, temperature, structure, and behavior during experiments. Direct measurements of the plasma's properties can be determined through modeling and by comparison with the state transition tables, using Optical Emission Spectroscopy (OES). The spectral probes will take advantage of HPX's magnetic field structure to define and measure the plasma's radiation temp as a function of time and space. In addition, the Thomson Scattering (TS) device will measure internal temperature and density data as the HPX plasma transitions through capacitive and inductive modes while developing into helicon plasma. Currently CGAPL is focused on building its laser beam transport and scattered light collection optical systems. Recently, HPX has acquired an Andor ICCD spectrometer for the spectral analysis. Data collected by the TS system will be logged in real time by CGAPL's Data Acquisition (DAQ) system with LabView remote access. Further progress on HPX will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY13.

  15. VUV spectroscopy of armor erosion from plasma gun disruption simulation experiments

    SciTech Connect

    Rockett, P.D.; Hunter, J.A.

    1994-12-31

    Extensive simulations of Tokamak disruptions have provided a picture of material erosion that is limited by the transfer of energy from the incident plasma to the armor solid surface through a dense vapor shield. The authors have designed and utilized two transmission grating vacuum ultraviolet (VUV) spectrographs to study the plasma-material interface in plasma gun simulation experiments. Target materials included POCO graphite, ATJ graphite, boron nitride, and plasma-sprayed tungsten. Detailed spectra were recorded with a spatial resolution of {approximately}0.7 mm resolution on VIKA at Efremov and on 2MK-200 at Troitsk. Time-resolved data with 40-200 ns resolution was then recorded along with the same spatial resolution on 2MK-200. The data from both plasma gun facilities demonstrated that the hottest plasma region was sitting several millimeters above the armor tile surface. This apparently constituted the absorption region, which confirmed past computer simulations. Spectra indicated both the species and ionization level that were being ablated from the target, demonstrating impurity content, and showing plasma ablation velocity. Graphite samples clearly showed C V lines as well as impurity lines from O V and O VI. The BN tiles produced textbook examples of B IV and B V, and extensive N IV, V, and VI lines. These are being compared to radiation-hydrodynamic calculations.

  16. First experiments probing the collision of parallel magnetic fields using laser-produced plasmas

    DOE PAGES

    Rosenberg, M. J.; Li, C. K.; Fox, W.; Igumenshchev, I.; Seguin, F. H.; Town, R. P.; Frenje, J. A.; Stoeckl, C.; Glebov, V.; Petrasso, R. D.

    2015-04-08

    Novel experiments to study the strongly-driven collision of parallel magnetic fields in β~10, laser-produced plasmas have been conducted using monoenergetic proton radiography. These experiments were designed to probe the process of magnetic flux pileup, which has been identified in prior laser-plasma experiments as a key physical mechanism in the reconnection of anti-parallel magnetic fields when the reconnection inflow is dominated by strong plasma flows. In the present experiments using colliding plasmas carrying parallel magnetic fields, the magnetic flux is found to be conserved and slightly compressed in the collision region. Two-dimensional (2D) particle-in-cell (PIC) simulations predict a stronger flux compressionmore » and amplification of the magnetic field strength, and this discrepancy is attributed to the three-dimensional (3D) collision geometry. Future experiments may drive a stronger collision and further explore flux pileup in the context of the strongly-driven interaction of magnetic fields.« less

  17. Modeling the heating and atomic kinetics of a photoionized neon plasma experiment

    NASA Astrophysics Data System (ADS)

    Lockard, Tom E.

    Motivated by gas cell photoionized plasma experiments performed by our group at the Z facility of Sandia National Laboratories, we discuss in this dissertation a modeling study of the heating and ionization of the plasma for conditions characteristic of these experiments. Photoionized plasmas are non-equilibrium systems driven by a broadband x-ray radiation flux. They are commonly found in astrophysics but rarely seen in the laboratory. Several modeling tools have been employed: (1) a view-factor computer code constrained with side x-ray power and gated monochromatic image measurements of the z-pinch radiation, to model the time-history of the photon-energy resolved x-ray flux driving the photoionized plasma, (2) a Boltzmann self-consistent electron and atomic kinetics model to simulate the electron distribution function and configuration-averaged atomic kinetics, (3) a radiation-hydrodynamics code with inline non-equilibrium atomic kinetics to perform a comprehensive numerical simulation of the experiment and plasma heating, and (4) steady-state and time-dependent collisional-radiative atomic kinetics calculations with fine-structure energy level description to assess transient effects in the ionization and charge state distribution of the plasma. The results indicate that the photon-energy resolved x-ray flux impinging on the front window of the gas cell is very well approximated by a linear combination of three geometrically-diluted Planckian distributions. Knowledge of the spectral details of the x-ray drive turned out to be important for the heating and ionization of the plasma. The free electrons in the plasma thermalize quickly relative to the timescales associated with the time-history of the x-ray drive and the plasma atomic kinetics. Hence, electrons are well described by a Maxwellian energy distribution of a single temperature. This finding is important to support the application of a radiation-hydrodynamic model to simulate the experiment. It is found

  18. Temporally and spatially resolved characterization of microwave induced argon plasmas: Experiment and modeling

    SciTech Connect

    Baeva, M. Andrasch, M.; Ehlbeck, J.; Loffhagen, D.; Weltmann, K.-D.

    2014-04-14

    Experiments and modeling of the plasma-microwave interaction have been performed in a coaxial microwave plasma source at a field frequency of 2.45 GHz generating argon plasmas at pressures of 20 and 40 millibars and a ratio of flow rate to pressure of 0.125 sccm/Pa. The incident microwave power between 100 W and 300 W is supplied in a regime of a pulse-width modulation with cycle duration of 110 ms and a power-on time of 23 ms. The experiments are based on heterodyne reflectometry and microwave interferometry at 45.75 GHz. They provide the temporal behaviour of the complex reflection coefficient, the microwave power in the plasma, as well as the electron density in the afterglow zone of the discharge. The self-consistent spatially two-dimensional and time-dependent modeling complements the analysis of the plasma-microwave interaction delivering the plasma and electromagnetic field parameters. The consolidating experimental observations and model predictions allow further characterizing the plasma source. The generated plasma has a core occupying the region close to the end of the inner electrode, where maximum electron densities above 10{sup 20} m{sup −3} and electron temperatures of about 1 eV are observed. Due to a longer outer electrode of the coaxial structure, the plasma region is extended and fills the volume comprised by the outer electrode. The electron density reaches values of the order of 10{sup 19} m{sup −3}. The heating of the gas occurs in its great part due to elastic collisions with the plasma electrons. However, the contribution of the convective heating is important especially in the extended plasma region, where the gas temperature reaches its maximum values up to approximately 1400 K. The temporally and spatially resolved modeling enables a thorough investigation of the plasma-microwave interaction which clearly shows that the power in-coupling occurs in the region of the highest electron density during the early stage of

  19. Extreme ultraviolet diagnostics of preformed plasma in laser-driven proton acceleration experiments

    SciTech Connect

    Ragozin, Eugene N.; Pirozhkov, Alexander S.; Yogo, Akifumi; Ma Jinglong; Ogura, Koichi; Orimo, Satoshi; Sagisaka, Akito; Mori, Michiaki; Li, Zhong; Nishiuchi, Mamiko; Daido, Hiroyuki

    2006-12-15

    Proton acceleration experiments involving a 5 {mu}m thick Ti foil target irradiation are carried out with the femtosecond Ti:sapphire laser JLITE-X. The plasma emission at 13.5 nm is recorded employing concave multilayer mirrors, which image the front- and rear-side plasmas onto the sensitive surfaces of a fast x-ray photodiode and a backside-illuminated charge coupled device. Online time-of-flight fast-particle measurements are performed simultaneously with the extreme ultraviolet (XUV) measurements. A strong correlation is observed between the energetic proton signal and the spatiotemporal behavior of the XUV plasma emission. In particular, the longer duration of the prepulse-produced XUV plasma emission indicates a lowering of the maximum proton energy. This allows using the XUV emission for the diagnostics of the high-intensity laser-solid-target interaction.

  20. 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.

  1. Exploration of spontaneous vortex formation and intermittent behavior in ECR plasmas: The HYPER-I experiments

    NASA Astrophysics Data System (ADS)

    Yoshimura, S.; Terasaka, K.; Tanaka, E.; Aramaki, M.; Okamoto, A.; Nagaoka, K.; Tanaka, M. Y.

    2015-04-01

    HYPER-I (High Density Plasma Experiment-I) is a linear device that combines a wide operation range of plasma production with flexible diagnostics. The plasmas are produced by the electron cyclotron resonance (ECR) heating with parallel injection of right-handed circularly polarized microwaves of 2.45 GHz from the high-field side. The maximum attainable electron density is more than two orders of magnitude higher than the cutoff density of ordinary waves. Spontaneous formation of a variety of large-scale flow structures, or vortices, has been observed in the HYPER-I plasmas. Flow-velocity field measurements using directional Langmuir probes (DLPs) and laser-induced fluorescence (LIF) method have clarified the physical processes behind such vortex formations. Recently, a new intermittent behavior of local electron temperature has also been observed. Statistical analysis of the floating potential changes has revealed that the phenomenon is characterized by a stationary Poisson process.

  2. 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.

  3. Studies of dynamic processes related to active experiments in space plasmas

    NASA Technical Reports Server (NTRS)

    Banks, Peter M.; Neubert, Torsten

    1992-01-01

    This is the final report for grant NAGw-2055, 'Studies of Dynamic Processes Related to Active Experiments in Space Plasmas', covering research performed at the University of Michigan. The grant was awarded to study: (1) theoretical and data analysis of data from the CHARGE-2 rocket experiment (1keV; 1-46 mA electron beam ejections) and the Spacelab-2 shuttle experiment (1keV; 100 mA); (2) studies of the interaction of an electron beam, emitted from an ionospheric platform, with the ambient neutral atmosphere and plasma by means of a newly developed computer simulation model, relating model predictions with CHARGE-2 observations of return currents observed during electron beam emissions; and (3) development of a self-consistent model for the charge distribution on a moving conducting tether in a magnetized plasma and for the potential structure in the plasma surrounding the tether. Our main results include: (1) the computer code developed for the interaction of electrons beams with the neutral atmosphere and plasma is able to model observed return fluxes to the CHARGE-2 sounding rocket payload; and (2) a 3-D electromagnetic and relativistic particle simulation code was developed.

  4. Active experiments in geospace plasmas with gigawatts of RF power at HAARP

    NASA Astrophysics Data System (ADS)

    Sheerin, James

    2016-07-01

    The ionosphere provides a relatively quiescent plasma target, stable on timescales of minutes, for a whole host of active plasma experiments. The largest HF transmitter built to date is the HAARP phased-array HF transmitter near Gakona, Alaska which can deliver up to 3.6 Gigawatts (ERP) of CW RF power in the range of 2.8 - 10 MHz to the ionosphere with millisecond pointing, power modulation, and frequency agility. With an ionospheric background thermal energy in the range of only 0.1 eV, this amount of power gives access to the highest regimes of the nonlinearity (RF intensity to thermal pressure) ratio. HAARP's unique features have enabled the conduct of a number of nonlinear plasma experiments in the inter¬action region of overdense ionospheric plasma including generation of artificial aurorae, artificial ionization layers, VLF wave-particle interactions in the magnetosphere, parametric instabilities, stimulated electromagnetic emissions (SEE), strong Langmuir turbulence (SLT) and suprathermal electron acceleration. Diagnostics include the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the SuperDARN-Kodiak HF radar, spacecraft radio beacons, HF receivers to record stimulated electromagnetic emissions (SEE) and optics for optical emissions. We report on short timescale ponderomotive overshoot effects, artificial field-aligned irregularities (AFAI), the aspect angle dependence of the intensity of the HF-enhanced plasma line, and production of suprathermal electrons. Applications are made to the controlled study of fundamental nonlinear plasma processes of relevance to laboratory plasmas, ionospheric irregularities affecting spacecraft communication and navigation systems, artificial ionization mirrors, wave-particle interactions in the magnetosphere, active global magnetospheric experiments, and many more.

  5. Temperature and Electron Density Determination on Laser-Induced Breakdown Spectroscopy (LIBS) Plasmas: A Physical Chemistry Experiment

    ERIC Educational Resources Information Center

    Najarian, Maya L.; Chinni, Rosemarie C.

    2013-01-01

    This laboratory is designed for physical chemistry students to gain experience using laser-induced breakdown spectroscopy (LIBS) in understanding plasma diagnostics. LIBS uses a high-powered laser that is focused on the sample causing a plasma to form. The emission of this plasma is then spectrally resolved and detected. Temperature and electron…

  6. Heating efficiency evaluation with mimicking plasma conditions of integrated fast-ignition experiment.

    PubMed

    Fujioka, Shinsuke; Johzaki, Tomoyuki; Arikawa, Yasunobu; Zhang, Zhe; Morace, Alessio; Ikenouchi, Takahito; Ozaki, Tetsuo; Nagai, Takahiro; Abe, Yuki; Kojima, Sadaoki; Sakata, Shohei; Inoue, Hiroaki; Utsugi, Masaru; Hattori, Shoji; Hosoda, Tatsuya; Lee, Seung Ho; Shigemori, Keisuke; Hironaka, Youichiro; Sunahara, Atsushi; Sakagami, Hitoshi; Mima, Kunioki; Fujimoto, Yasushi; Yamanoi, Kohei; Norimatsu, Takayoshi; Tokita, Shigeki; Nakata, Yoshiki; Kawanaka, Junji; Jitsuno, Takahisa; Miyanaga, Noriaki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Nagatomo, Hideo; Azechi, Hiroshi

    2015-06-01

    A series of experiments were carried out to evaluate the energy-coupling efficiency from heating laser to a fuel core in the fast-ignition scheme of laser-driven inertial confinement fusion. Although the efficiency is determined by a wide variety of complex physics, from intense laser plasma interactions to the properties of high-energy density plasmas and the transport of relativistic electron beams (REB), here we simplify the physics by breaking down the efficiency into three measurable parameters: (i) energy conversion ratio from laser to REB, (ii) probability of collision between the REB and the fusion fuel core, and (iii) fraction of energy deposited in the fuel core from the REB. These three parameters were measured with the newly developed experimental platform designed for mimicking the plasma conditions of a realistic integrated fast-ignition experiment. The experimental results indicate that the high-energy tail of REB must be suppressed to heat the fuel core efficiently. PMID:26172803

  7. High-energy 4{omega} probe laser for laser-plasma experiments at nova

    SciTech Connect

    Glenzer, S. H., LLNL

    1998-06-02

    For the characterization of inertial confinement fusion plasmas we implemented a high-energy 4{omega} probe laser at the Nova laser facility. A total energy of > 50 Joules at 4{omega}, a focal spot size of order 100 {micro}m, and a pointing accuracy of 100 {micro}m was demonstrated for target shots. This laser provides intensities of up to 3 x 10{sup 14}W cm{sup -2} and therefore fulfills high-power requirements for laser-plasma interaction experiments. The 4{omega} probe laser is now routinely used for Thomson scattering. Successful experiments were performed in gas-filled hohlraums at electron densities of n{sub e} > 2 X 10{sup 21}cm{sup -3} which represents the highest density plasma so far being diagnosed with Thomson scattering.

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

    SciTech Connect

    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 this 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.

  9. Heating efficiency evaluation with mimicking plasma conditions of integrated fast-ignition experiment.

    PubMed

    Fujioka, Shinsuke; Johzaki, Tomoyuki; Arikawa, Yasunobu; Zhang, Zhe; Morace, Alessio; Ikenouchi, Takahito; Ozaki, Tetsuo; Nagai, Takahiro; Abe, Yuki; Kojima, Sadaoki; Sakata, Shohei; Inoue, Hiroaki; Utsugi, Masaru; Hattori, Shoji; Hosoda, Tatsuya; Lee, Seung Ho; Shigemori, Keisuke; Hironaka, Youichiro; Sunahara, Atsushi; Sakagami, Hitoshi; Mima, Kunioki; Fujimoto, Yasushi; Yamanoi, Kohei; Norimatsu, Takayoshi; Tokita, Shigeki; Nakata, Yoshiki; Kawanaka, Junji; Jitsuno, Takahisa; Miyanaga, Noriaki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Nagatomo, Hideo; Azechi, Hiroshi

    2015-06-01

    A series of experiments were carried out to evaluate the energy-coupling efficiency from heating laser to a fuel core in the fast-ignition scheme of laser-driven inertial confinement fusion. Although the efficiency is determined by a wide variety of complex physics, from intense laser plasma interactions to the properties of high-energy density plasmas and the transport of relativistic electron beams (REB), here we simplify the physics by breaking down the efficiency into three measurable parameters: (i) energy conversion ratio from laser to REB, (ii) probability of collision between the REB and the fusion fuel core, and (iii) fraction of energy deposited in the fuel core from the REB. These three parameters were measured with the newly developed experimental platform designed for mimicking the plasma conditions of a realistic integrated fast-ignition experiment. The experimental results indicate that the high-energy tail of REB must be suppressed to heat the fuel core efficiently.

  10. Evolution of plasma loops in a semi-toroidal pinch experiment

    SciTech Connect

    Mackel, F. Ridder, S.; Tenfelde, J.; Tacke, T.; Soltwisch, H.

    2015-04-15

    The FlareLab experiment is a pulsed-power discharge generating magnetized plasma loops similar to a pinch experiment in a semi-toroidal configuration. After gas breakdown along a circular magnetic guide field, the structure expands in its major radius as the plasma becomes highly conductive and the discharge current rises. Photographs, current and electron density measurements reveal a significant broadening in the lateral direction leading to an increasing departure from radial symmetry of plasma parameters in the cross section. It is shown that the luminosity is related to both high electron density and high current density. Simultaneous measurements of current density and electric field reveal a high parallel resistivity of the plasma leading to fast diffusion across the magnetic field. Indications for anomalous resistivity are found by comparison with the Spitzer formula. As the experiment differs from a z-pinch experiment only by the semi-circular shape of the current path, the observed evolution is unexpected and might be of more fundamental significance.

  11. Experiments in diamond film fabrication in table-top plasma apparatus

    NASA Technical Reports Server (NTRS)

    Masi, James V.

    1994-01-01

    The objectives of this experiment are to illustrate the process of plasma assisted chemical vapor deposition and to show devices which can be made simply in the laboratory. These devices illustrate clearly the concepts of bandgap, junctions, and photoelectronic processes. Films and devices are measured electrically, optically, and thermally.

  12. Numerical modeling of Large Plasma Device Alfvén wave experiments using AstroGK

    NASA Astrophysics Data System (ADS)

    Nielson, Kevin D.; Howes, Gregory G.; Tatsuno, Tomoya; Numata, Ryusuke; Dorland, William

    2010-02-01

    Collisions between counterpropagating Alfvén waves represent the fundamental building block of plasma turbulence, a phenomenon of great importance to a wide variety of fields, from space physics and astrophysics to controlled magnetic fusion. Proposed experiments to study Alfvén wave collisions on the Large Plasma Device (LAPD) [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)] at the University of California, Los Angeles, will benefit significantly from numerical modeling capable of reproducing not only the linear dispersive effects of kinetic and inertial Alfvén waves, but also the nonlinear evolution of the Alfvénic turbulence. This paper presents a comparison of linear simulation results using the astrophysical gyrokinetics code, AstroGK, to the measured linear properties of kinetic and inertial Alfvén waves in the LAPD plasma. Results demonstrate that: (1) finite frequency effects due to the ion cyclotron resonance do not prevent satisfactory modeling of the LAPD plasma using gyrokinetic theory; and (2) an advanced collision operator, recently implemented in AstroGK, enables the code to successfully reproduce the collisionally enhanced damping rates of linear waves measured in recent LAPD experiments. These tests justify the use of AstroGK in the modeling of LAPD Alfvén wave experiments and suggest that AstroGK will be a valuable tool in modeling the nonlinear evolution of proposed Alfvén wave collision experiments.

  13. An 1.2 MJ Capacitor Bank 'RUDRA' for MTF and Plasma Focus Experiments

    SciTech Connect

    Verma, Rishi; Shyam, A.; Chaturvedi, S.; Kumar, R.; Lathi, D.; Chaudhary, V.; Shukla, R.; Debnath, K.; Sharma, S.; Sonara, J.; Shah, K.; Adhikary, B.; Bhavsar, T.; Mehida, R.; Mehta, C.

    2006-01-05

    Pinch experiments like Magnetized Target Fusion (MTF) and Dense Plasma Focus require for their operation fast rising high power and high energy pulses. To perform such experiments, an 1.2MJ Capacitor Bank capable of delivering 3.6MA of peak current with 5 to 7{mu}s rise time has been designed and commissioned. The major application of bank is focused on fast discharge applications where large peak currents are required.

  14. The proceedings of the 1st international workshop on laboratory astrophysics experiments with large lasers

    SciTech Connect

    Remington, B.A.; Goldstein, W.H.

    1996-08-09

    The world has stood witness to the development of a number of highly sophisticated and flexible, high power laser facilities (energies up to 50 kJ and powers up to 50 TW), driven largely by the world-wide effort in inertial confinement fusion (ICF). The charter of diagnosing implosions with detailed, quantitative measurements has driven the ICF laser facilities to be exceedingly versatile and well equipped with diagnostics. Interestingly, there is considerable overlap in the physics of ICF and astrophysics. Both typically involve compressible radiative hydrodynamics, radiation transport, complex opacities, and equations of state of dense matter. Surprisingly, however, there has been little communication between these two communities to date. With the recent declassification of ICF in the USA, and the approval to commence with construction of the next generation ``superlasers``, the 2 MJ National Ignition Facility in the US, and its equivalent, the LMJ laser in France, the situation is ripe for change. . Given the physics similarities that exist between ICF and astrophysics, one strongly suspects that there should exist regions of overlap where supporting research on the large lasers could be beneficial to the astrophysics community. As a catalyst for discussions to this end, Lawrence Livermore National Laboratory sponsored this workshop. Approximately 100 scientists attended from around the world, representing eight countries: the USA, Canada, UK, France, Germany, Russia, Japan, and Israel. A total of 30 technical papers were presented. The two day workshop was divided into four sessions, focusing on nonlinear hydrodynamics, radiative hydrodynamics, radiation transport, and atomic physics-opacities. Copies of the presentations are contained in these proceedings.

  15. Search for 1st Generation Leptoquarks in the eejj channel with the DZero experiment

    SciTech Connect

    Barfuss, Anne-Fleur

    2008-09-12

    An evidence of the existence of leptoquarks (LQ) would prove the validity of various extensions of the Standard Model of Particle Physics (SM). The search for first generation leptoquarks presented in this dissertation has been performed by analyzing a 1.02 fb-1 sample of data collected by the D0 detector, events with a final state comprising two light jets and two electrons. The absence of an excess of events in comparison to SM expectations leads to exclude scalar LQ masses up to 292 GeV and vector LQ masses from 350 to 458 GeV, depending on the LQ-l-q coupling type. The great importance of a good jet energy measurement motivated the study of the instrumental backgrounds correlated to the calorimeter, as much as studies of the hadronic showers energy resolution in γ + jets events.

  16. Experience from the 1st Year running a Massive High Quality Videoconferencing Service for the LHC

    NASA Astrophysics Data System (ADS)

    Fernandes, Joao; Baron, Thomas; Bompastor, Bruno

    2014-06-01

    In the last few years, we have witnessed an explosion of visual collaboration initiatives in the industry. Several advances in video services and also in their underlying infrastructure are currently improving the way people collaborate globally. These advances are creating new usage paradigms: any device in any network can be used to collaborate, in most cases with an overall high quality. To keep apace with this technology progression, the CERN IT Department launched a service based on the Vidyo product. This new service architecture introduces Adaptive Video Layering, which dynamically optimizes the video for each endpoint by leveraging the H.264 Scalable Video Coding (SVC)-based compression technology. It combines intelligent AV routing techniques with the flexibility of H.264 SVC video compression, in order to achieve resilient video collaboration over the Internet, 3G and WiFi. We present an overview of the results that have been achieved after this major change. In particular, the first year of operation of the CERN Vidyo service will be described in terms of performance and scale: The service became part of the daily activity of the LHC collaborations, reaching a monthly usage of more than 3200 meetings with a peak of 750 simultaneous connections. We also present some key features such as the integration with CERN Indico. LHC users can now join a Vidyo meeting either from their personal computer or a CERN videoconference room simply from an Indico event page, with the ease of a single click. The roadmap for future improvements, service extensions and core infrastructure tendencies such as cloud based services and virtualization of system components will also be discussed. Vidyo's strengths allowed us to build a universal service (it is accessible from PCs, but also videoconference rooms, traditional phones, tablets and smartphones), developed with 3 key ideas in mind: ease of use, full integration and high quality.

  17. Deuterium flux measurements in the edge plasmas of PLT and PDX during auxiliary heating experiments

    SciTech Connect

    Wampler, W.R.; Cohen, S.A.; Dylla, H.F.; Manos, D.M.; Magee, C.W.

    1981-01-01

    The flux of deuterium in the plasma edge several centimeters outside the limiter has been measured using collector probes during neutral beam heating experiments on the PDX tokamak and RF heating experiments on the PLT tokamak. The dependence of the flux on the distance from the plasma was determined, and the time dependence of the flux was measured with a time resolution of 90 ms. In PDX the deuterium flux decreased rapidly with increasing distance from the plasma. The deuterium flux increased strongly when the beams came on and decreased when they turned off. The depth distribution of the deuterium in the samples, measured using SIMS, shows that when the beams are on about 30% of the deuterium incident on the probe is superthermal deuterium from the beams. In PLT the deuterium flux decreased only slightly with increasing distance from the plasma. The ICRH heating in PLT caused an increase of about 30% in the flux of deuterium to the samples and in the plasma density. In both machines the deuterium fluxes were fairly low (less than or equal to 10/sup 16/D/cm/sup 2/s) at the positions sampled.

  18. Deuterium flux measurements in the edge plasmas of PLT and PDX during auxiliary heating experiments

    SciTech Connect

    Wampler, W.R.; Cohen, S.A.; Dylla, H.F.; Manos, D.M.; Magee, C.W.

    1982-04-01

    The flux of deuterium in the plasma edge several centimeters outside the limiter has been measured using collector probes during neutral beam heating experiments on the PDX tokamak and rf heating experiments on the PLT tokamak. The dependence of the flux on the distance from the plasma was determined, and the time dependence of the flux was measured with a time resolution of 90 ms. In PDX the deuterium flux decreases rapidly with increasing distance from the plasma. The deuterium flux increased strongly when the beams came on and decreased when they turned off. The depth distribution of the deuterium in the samples, measured using SIMS, shows that when the beams are on, about 30% of the deuterium incident on the probe is superthermal deuterium from the beams. In PLT the deuterium flux decreased only slightly with increasing distance from the plasma. The ICRH heating in PLT caused an increase of about 30% in the flux of deuterium to the samples and in the plasma density. In both machines the deuterium fluxes were fairly low (< or approx. =10/sup 16/ D/cm/sup 2/s) at the positions sampled.

  19. Updates on Optical Emission Spectroscopy & Langmuir Probe Investigations on the Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    Karama, Jackson; Frank, John; Azzari, Phillip; Hopson, Jordan; James, Royce; Duke-Tinson, Omar; Paolino, Richard; Sandri, Eva; Sherman, Justin; Wright, Eva; Turk, Jeremy

    2015-11-01

    HPX is developing a to shorter lifetime (20 - 30 ns) more reproducible plasma at the Coast Guard Academy Plasma Laboratory (CGAPL). Once achieved, spectral and particle probes will help to verify plasma mode transitions to the W-mode. These optical probes utilize movable filters, and ccd cameras to gather data at selected spectral frequency bands. Once corrections for the RF field are in place for the Langmuir probe, raw data will be collected and used to measure the plasma's density, temperature, and potentially the structure and behavior during experiments. Direct measurements of plasma properties can be determined with modeling and by comparison with the state transition tables, both using Optical Emission Spectroscopy (OES). The spectral will add to HPX's data collection capabilities and be used in conjunction with the particle probes, and Thomson Scattering device to create a robust picture of the internal and external plasma parameters on HPX. Progress on the implementation of the OES and Langmuir probes will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY15.

  20. Analysis of Data From Z-Pinch MTF Target-Plasma Experiments

    NASA Astrophysics Data System (ADS)

    Taccetti, J. M.; Wysocki, F. J.; Benage, J. F.; Idzorek, G.; Oona, H.; Kirkpatrick, R. C.; Lindemuth, I. R.; Sheehey, P. T.

    1999-11-01

    Magnetized Target Fusion (MTF) target-plasma experiments have been performed at Los Alamos National Laboratory Colt facility for roughly three years(F. J. Wysocki et al., Digest of Technical Papers for the 11th IEEE International Pulsed Power Conference, Baltimore, Maryland, June 29 to July 2, 1997, G. Cooperstein and I. Vitkovitsky editors, p. 1393.). The capacitor bank has a max output voltage of 120 kV, max energy store of 0.25 MJ, and can deliver at least 2 MA of current to a load in 2.5 μs. The MTF target plasma is generated by driving a z-directed current through a plasma which is contained by a 2 cm radius by 2 cm high cylindrical metal wall. The initial mass for the target plasma comes from either a static uniform fill of hydrogen or deuterium gas, or from a polyethylene fiber mounted along the central axis. The diagnostic set includes an array of 12 B-dot probes, optical framing camera, gated OMA visible spectrometer, time-resolved monochrometer, filtered silicon photodiodes, neutron yield, and a laser interferometer. Measurements of the plasma temperature and impurity content obtained to date with a transmission grating spectrometer will also be presented. The data obtained allows an assessment of the plasma temperature, density, magnetization, and decay time.

  1. Long Pulse High Performance Plasma Scenario Development for the National Spherical Torus Experiment

    SciTech Connect

    Kessel, C.E.; Bell, R.E.; Bell, M.G.; Gates, D.A.; Harvey, R.W.

    2006-01-01

    The National Spherical Torus Experiment [Ono et al., Nucl. Fusion, 44, 452 (2004)] is targeting long pulse high performance, noninductive sustained operations at low aspect ratio, and the demonstration of nonsolenoidal startup and current rampup. The modeling of these plasmas provides a framework for experimental planning and identifies the tools to access these regimes. Simulations based on neutral beam injection (NBI)-heated plasmas are made to understand the impact of various modifications and identify the requirements for (1) high elongation and triangularity, (2) density control to optimize the current drive, (3) plasma rotation and/or feedback stabilization to operate above the no-wall limit, and (4) electron Bernstein waves (EBW) for off-axis heating/current drive (H/CD). Integrated scenarios are constructed to provide the transport evolution and H/CD source modeling, supported by rf and stability analyses. Important factors include the energy confinement, Zeff, early heating/H mode, broadening of the NBI-driven current profile, and maintaining q(0) and qmin>1.0. Simulations show that noninductive sustained plasmas can be reached at IP=800 kA, BT=0.5 T, 2.5, N5, 15%, fNI=92%, and q(0)>1.0 with NBI H/CD, density control, and similar global energy confinement to experiments. The noninductive sustained high plasmas can be reached at IP=1.0 MA, BT=0.35 T, 2.5, N9, 43%, fNI=100%, and q(0)>1.5 with NBI H/CD and 3.0 MW of EBW H/CD, density control, and 25% higher global energy confinement than experiments. A scenario for nonsolenoidal plasma current rampup is developed using high harmonic fast wave H/CD in the early low IP and low Te phase, followed by NBI H/CD to continue the current ramp, reaching a maximum of 480 kA after 3.4 s.

  2. Empirical Modeling of Plasma Clouds Produced by the Metal Oxide Space Clouds (MOSC) Experiment

    NASA Astrophysics Data System (ADS)

    Pedersen, T.; Caton, R. G.; Miller, D.; Holmes, J. M.; Groves, K. M.

    2015-12-01

    The Metal Oxide Space Clouds (MOSC) chemical release experiments employed the ALTAIR radar as a primary measurement of plasma density in the clouds. However, the radar provides only the local plasma density along the beam line of sight, and the measurements are of limited value without context to determine the location of the radar beam relative to the larger plasma cloud. We have constructed an empirical model of the cloud locations, shapes, and sizes as a function of time for both MOSC launches using fits to all-sky images recorded from near the launch site. When combined with ALTAIR radar measurements of local plasma density at the sampled point and ionosonde measurements of the peak plasma density, a robust 4-D representation of the plasma density can be derived and used to estimate ionization yields and to study impacts on the background ionosphere and RF propagation. Optical image data was fit to a 2-D Gaussian model to derive peak intensity, background, rotation of the cloud in the horizontal plane, and half-widths in the N-S and E-W directions. The optical images show a closely linear increase in half-width after the first minute or two. Very good agreement between the model and radar integrated total electron content (TEC) measurements are obtained with a simple exponential envelope to the peak TEC within the cloud, indicating that the optical distribution closely tracks the plasma density. Comparison of TEC with peak plasma density and the observed spatial dimensions of the cloud are used to estimate the rate of change in total electron number during the period of observation and to compare with predictions of prior theoretical and numerical models.

  3. Electromagnetic Safety of Spacecraft During Active Experiments with the Use of Plasma Accelerators and Ion Injectors

    NASA Astrophysics Data System (ADS)

    Plokhikh, Andrey; Popov, Garri; Shishkin, Gennady; Antropov, Nikolay; Vazhenin, Nikolay; Soganova, Galina

    Works under the development and application of stationary and pulsed plasma accelerators of charged particles conducted at the Moscow Aviation Institute and Research Institute of Applied Mechanics and Electrodynamics during over 40 years, active experiments on board meteorological rockets, artificial Earth satellites and "Mir" orbital station including [1], allowed to obtain data on the influence of pulsed and continuous plasma injection with the given parameters on the drop of energetic particles out of the radiation belts, efficiency of artificial excitation and propagation of electromagnetic waves in ELF and VLF ranges, and evolution of artificial plasma formations in different regions of ionosphere. Variation of the near-spacecraft electromagnetic environment related to the operation of plasma injectors was registered during active experiments along with the global electrodynamic processes. The measured electromagnetic fields are of rather high intensity and occupy frequency spectrum from some Hz to tens of GHz that may be of definite danger for the operation of spacecraft and its onboard systems. Analysis for the known test data is presented in the paper and methods are discussed for the diagnostics and modeling under laboratory conditions of radiative processes proceeding at the operation of plasma accelerators and ion injectors used while making active space experiments. Great attention is paid to the methodological and metrological bases for making radio measurements in vacuum chambers, design concept and hardware configuration of ground special-purpose instrumentation scientific complexes [2]. Basic requirements are formulated for the measurements and analysis of electromagnetic fields originating during the operation of plasma accelerators, including the radiative induced and conductive components inside the spacecraft, as well as the wave emission and excitation outside the spacecraft, in the ionosphere including. Measurement results for the intrinsic

  4. ECH Plasma Experiments on an Internal Coil Device with a High Temperature Superconductor Coil

    SciTech Connect

    Ogawa, Yuichi; Morikawa, Junji; Ohkuni, Kotaro; Yamakoshi, Shigeo; Goto, Takuya; Mito, Toshiyuki; Yanagi, Nagato; Iwakuma, Masataka

    2005-01-15

    Self-organization related with relaxation phenomenon is playing an important role in various aspects of magnetic confined plasmas. Recently a relaxation theory including the plasma flow has been developed by Mahajan-Yoshida, and a new relaxation state has been identified. The two-fluid relaxation condition is given by {beta} + (V/V{sub A}){sup 2} = const. To study a self-organized structure with strong plasma flow, we have introduced an internal coil device. By inducing a radial electric field with appropriate methods, we could drive a toroidal plasma flow, and confine a high beta plasma in a core region. The internal coil device Mini-RT with a high temperature superconductor(HTS) coil(Rc=0.15m, Ic=50kA) has been constructed. The vacuum chamber is 1 m in diameter and {approx}0.7 m in height. The magnetic field strength near the internal coil is around 0.1 T, and a radio-frequency wave of 2.45 GHz is applied for the plasma production. We have started ECH plasma experiments with the coil supported mechanically. The electron density, which has a peak near the internal coil, is of order 10{sup 16} m{sup -3}, reaching the cut-off density of the microwave. While, the electron temperature is of order 10 eV with a broad profile. Estimated energy confinement time is of order 10{sup -(5-6)} sec. The levitation experiment of the HTS coil has been carried out. The position of the HTS coil is measured with laser sensors, and is feedback-controlled with the levitation coil current. We have succeeded to levitating the HTS coil during one hour with an accuracy of less than 20 {omega}m. A preliminary experiment for the plasma production at the floating condition of the HTS coil has been initiated. It is affirmed that the levitation system works well and plasma with separatrix configuration is produced.

  5. PREFACE: 1st International Conference on Mechanical Engineering Research 2011 (ICMER2011)

    NASA Astrophysics Data System (ADS)

    Abu Bakar, Rosli

    2012-09-01

    The year 2010 represented a significant milestone in the history of the Mechanical Engineering community with the organization of the first and second national level conferences (National Conference in Mechanical Engineering for Research, 1st and 2nd NCMER) at Universiti Malaysia Pahang on 26-27 May and 3-4 December 2010. The conferences attracted a large number of delegates from different premier academic and research institutions in the country to participate and share their research experiences at the conference. The International Conference on Mechanical Engineering Research (ICMER 2011) followed on from the first and second conferences due to good support from researchers. The ICMER 2011 is a good platform for researchers and postgraduate students to present their latest finding in research. The conference covers a wide range of topics including the internal combustion engine, machining processes, heat and mass transfer, fuel, biomechanical analysis, aerodynamic analysis, thermal comfort, computational techniques, design and simulation, automotive transmission, optimization techniques, hybrid electric vehicles, engine vibration, heat exchangers, finite element analysis, computational fluid dynamics, green energy, vehicle dynamics renewable energy, combustion, design, product development, advanced experimentation techniques, to name but a few. The international conference has helped to bridge the gap between researchers working at different institutions and in different countries to share their knowledge and has helped to motivate young scientists with their research. This has also given some clear direction for further research from the deliberations of the conference. Several people have contributed in different ways to the success of the conference. We thank the keynote speakers and all authors of the contributed papers, for the cooperation rendered to us in the publication of the CD conference proceedings. In particular, we would like to place on record our

  6. Cold pulse experiments in plasma with an electron internal transport barrier on LHD

    NASA Astrophysics Data System (ADS)

    Inagaki, S.; Ida, K.; Tamura, N.; Shimozuma, T.; Kubo, S.; Nagayama, Y.; Kawahata, K.; Sudo, S.; Ohkubo, K.; LHD Experimental Group

    2004-05-01

    Transient transport experiments are performed in LHD plasma with electron internal transport barrier (e-ITB). Evidence for a reduction of electron heat diffusivity inside the ITB is observed from cold and heat pulse propagations. The observed enhancement of the cold pulse peak is explained by the temperature dependent electron heat diffusivity. The heat diffusivity inside the ITB decreases with an increase in the electron temperature in LHD. A preliminary version of this study was presented in the 29th EPS Conf. on Plasma Phys. and Control. Fusion (Montreux, Switzerland, 17 21 June 2002) [1].

  7. Surface Treatment of a Lithium Limiter for Spherical Torus Plasma Experiments

    SciTech Connect

    Kaita, R.; Majeski, R.; Doerner, R.; Antar, G.; Timberlake, J.; Spaleta, J.; Hoffman, D.; Jones, B.; Munsat, T.; Kugel, H.; Taylor, G.; Stutman, D.; Soukhanovskii, V.; Maingi, R.; Molesa, S.; Efthimion, P.; Menard, J.; Finkenthal, M.; Luckhardt, S.

    2001-03-20

    The concept of a flowing lithium first wall for a fusion reactor may lead to a significant advance in reactor design, since it could virtually eliminate the concerns with power density and erosion, tritium retention, and cooling associated with solid walls. As part of investigations to determine the feasibility of this approach, plasma interaction questions in a toroidal plasma geometry are being addressed in the Current Drive eXperiment-Upgrade (CDX-U) spherical torus (ST). The first experiments involved a toroidally local lithium limiter (L3). Measurements of pumpout rates indicated that deuterium pumping was greater for the L3 compared to conventional boron carbide limiters. The difference in the pumpout rates between the two limiter types decreased with plasma exposure, but argon glow discharge cleaning was able to restore the pumping effectiveness of the L3. At no point, however, was the extremely low recycling regime reported in previous lithium experiments achieved. This may be due to the much larger lithium surfaces that were exposed to the plasma in the earlier work. The possibility will be studied in the next set of CDX-U experiments, which are to be conducted with a large area, fully toroidal lithium limiter.

  8. Idaho National Laboratory Quarterly Performance Analysis - 1st Quarter FY2015

    SciTech Connect

    Mitchell, Lisbeth A.

    2015-03-01

    This report is published quarterly by the Idaho National Laboratory (INL) Quality and Performance Management Organization. The Department of Energy (DOE) Occurrence Reporting and Processing System (ORPS), as prescribed in DOE Order 232.2, “Occurrence Reporting and Processing of Operations Information,” requires a quarterly analysis of events, both reportable and not reportable, for the previous 12 months. This report is the analysis of 73 reportable events (27 from the 1St Qtr FY-15 and 46 from the prior three reporting quarters), as well as 38 other issue reports (including nine not reportable events and Significant Category A and B conditions reported during the1st Qtr FY-15) identified at INL during the past 12 months.

  9. Effect of 1st-trimester loss on restoration of the hypothalamic-pituitary-ovarian axis.

    PubMed

    Elkas, J C; Cunningham, D S

    1995-01-01

    This randomized prospective study was conducted to determine the length of time required for re-establishment of the reproductive axis following a 1st-trimester spontaneous abortion. The spontaneous gonadotropin secretion was significantly depressed during the first menstrual cycle after pregnancy loss, while the estradiol levels had normalized. Provocative testing revealed blunted gonadotropin release in the first menstrual cycle with return to normal during the first menstrual cycle after a spontaneous abortion. Endometrial biopsy specimens were also abnormal during the first menstrual cycle with normal histological characteristics by the second menstrual cycle. Therefore, restoration of the hypothalamic-pituitary- ovarian axis after a 1st-trimester loss is achieved within two menstrual cycles, as determined by return of normal pituitary function.

  10. A two-color terawatt laser system for high-intensity laser-plasma experiments

    NASA Astrophysics Data System (ADS)

    Sanders, James; Zgadzaj, Rafal; Downer, Michael

    2012-10-01

    In some high-field laser-plasma experiments, it is advantageous to accompany the main high-energy (˜1 J) laser with a second high-energy pulse (˜0.1 J) which has been frequency-shifted by ˜10%. Such a pulse-pair would have a low walk-off velocity while remaining spectrally distinct for use in two-color pump-probe experiments. Moreover, by shifting the second pulse by ˜plasma frequency, it is theoretically possible to enhance or suppress relativistic self-focusing, which is the first (uncontrolled) step in many laser-plasma experiments. We report a hybrid chirped pulse Raman amplifier (CPRA)/Ti-Sapphire amplifier (>200 mJ, 15-20 nm bandwidth (FWHM), >60 fs duration) that is capable of performing such two-color high-field experiments. When amplified and compressed, this beam's power exceeds 1 TW. This two-color capability can be added to any commercial terawatt laser system without compromising the energy, duration or beam quality of the main system. We will report progress with a two-color seeded relativistic self-phase modulation experiment.

  11. 44. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    44. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st St. S., Columbus, Ms. Detail from Camille Drie's map: A Bird's Eye View of Columbus, Mississippi ca. 1875-76. Shows M&O RR bridge before the Phoenix Bridge Co. erected iron truss spans in 1878. Credit: Photostat of map in Lowndes Co. Public Library Sarcone Photography, Columbus, Ms. 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  12. 43. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    43. MISSISSIPPI, LOWNDES CO. COLUMBUS RAILROAD BRIDGE End of 1st St. S., Columbus, Ms. Copy of photo 1900. Shows 1878 M&O RR bridge. The steamboat, 'Gopher,' in foreground, was an archeological survey vessel from the Franklin Institute in Philadelphia. Published in Art in Mississippi (1901). Credit: Copied from print in Lowndes Co. Public Library by Sarcone Photography, Columbus, Ms. 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  13. 46. NORTH END OF MILL NO. 2, 1st FLOOR, BELOW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    46. NORTH END OF MILL NO. 2, 1st FLOOR, BELOW PICKER AND CLOTH ROOM AREA. FUNCTION OF THIS SPACE UNKNOWN AT PRESENT. NOTE THAT EYE BEAM REPLACES ORIGINAL WALL OF 1892 PICKER HOUSE. CENTER (OR LEFT) DOOR IS ENTRY TO MILL NO. 2. RIGHT DOOR IS ENTRY TO 1892 NAPPER ROOM. - Prattville Manufacturing Company, Number One, 242 South Court Street, Prattville, Autauga County, AL

  14. 7. Photographic copy of original construction drawing, ELECTRICAL 1ST AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Photographic copy of original construction drawing, ELECTRICAL 1ST AND 2ND FLOOR PLANS, SHEET 10 of 11, DRAWING NO. 35-03-05 SF 5/1677, U.S. Army Engineer District, Detroit, Corps of Engineers, 9 June, 1959, on file Selfridge Base Museum. - Selfridge Field, Building No. 1041, West of E Street, north of D Street, Mount Clemens, Macomb County, MI

  15. Ruthenium indenylidene "1(st) generation" olefin metathesis catalysts containing triisopropyl phosphite.

    PubMed

    Guidone, Stefano; Nahra, Fady; Slawin, Alexandra M Z; Cazin, Catherine S J

    2015-01-01

    The reaction of triisopropyl phosphite with phosphine-based indenylidene pre-catalysts affords "1(st) generation" cis-complexes. These have been used in olefin metathesis reactions. The cis-Ru species exhibit noticeable differences with the trans-Ru parent complexes in terms of structure, thermal stability and reactivity. Experimental data underline the importance of synergistic effects between phosphites and L-type ligands.

  16. Ruthenium indenylidene “1st generation” olefin metathesis catalysts containing triisopropyl phosphite

    PubMed Central

    Guidone, Stefano; Nahra, Fady; Slawin, Alexandra M Z

    2015-01-01

    Summary The reaction of triisopropyl phosphite with phosphine-based indenylidene pre-catalysts affords “1st generation” cis-complexes. These have been used in olefin metathesis reactions. The cis-Ru species exhibit noticeable differences with the trans-Ru parent complexes in terms of structure, thermal stability and reactivity. Experimental data underline the importance of synergistic effects between phosphites and L-type ligands. PMID:26425210

  17. Ruthenium indenylidene "1(st) generation" olefin metathesis catalysts containing triisopropyl phosphite.

    PubMed

    Guidone, Stefano; Nahra, Fady; Slawin, Alexandra M Z; Cazin, Catherine S J

    2015-01-01

    The reaction of triisopropyl phosphite with phosphine-based indenylidene pre-catalysts affords "1(st) generation" cis-complexes. These have been used in olefin metathesis reactions. The cis-Ru species exhibit noticeable differences with the trans-Ru parent complexes in terms of structure, thermal stability and reactivity. Experimental data underline the importance of synergistic effects between phosphites and L-type ligands. PMID:26425210

  18. On the Observation of Jitter Radiation in Solid-Density Laser-Plasma Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    Keenan, Brett; Medvedev, Mikhail

    2015-11-01

    Plasmas created by high-intensity lasers are often subject to the formation of kinetic-streaming instabilities, such as the Weibel instability, which lead to the spontaneous generation of high-amplitude, tangled magnetic fields. These fields typically exist on small spatial scales, i.e., ``sub-Larmor scales''. Radiation from charged particles moving through small-scale electromagnetic (EM) turbulence, known as jitter radiation, has spectral characteristics distinct from both synchrotron and cyclotron radiation, and it carries valuable information on the statistical properties of the EM field structure and evolution. Consequently, jitter radiation from laser-produced plasmas may offer insight into the underlying electromagnetic turbulence. Here we investigate the prospects for, and demonstrate the feasibility of, such direct radiative diagnostics for mildly relativistic, solid-density laser plasmas produced in lab experiments. Supported by grant DOE grant DE-FG02-07ER54940 and NSF grant AST-1209665.

  19. The effect of boundaries on the ion acoustic beam-plasma instability in experiment and simulation

    SciTech Connect

    Rapson, Christopher; Grulke, Olaf; Matyash, Konstantin; Klinger, Thomas

    2014-05-15

    The ion acoustic beam-plasma instability is known to excite strong solitary waves near the Earth's bow shock. Using a double plasma experiment, tightly coupled with a 1-dimensional particle-in-cell simulation, the results presented here show that this instability is critically sensitive to the experimental conditions. Boundary effects, which do not have any counterpart in space or in most simulations, unavoidably excite parasitic instabilities. Potential fluctuations from these instabilities lead to an increase of the beam temperature which reduces the growth rate such that non-linear effects leading to solitary waves are less likely to be observed. Furthermore, the increased temperature modifies the range of beam velocities for which an ion acoustic beam plasma instability is observed.

  20. National Spherical Torus Experiment Real Time Plasma Control Data Acquisition Hardware

    SciTech Connect

    R.J. Marsala; J. Schneider

    2002-08-05

    The National Spherical Torus Experiment (NSTX) is currently providing researchers data on low aspect-ratio toroidal plasmas. NSTX's Plasma Control System adjusts the firing angles of thyristor rectifier power supplies, in real time, to control plasma position, shape and density. A Data Acquisition system comprised of off-the-shelf and custom hardware provides the magnetic diagnostics data required in calculating firing angles. This VERSAmodule Eurocard (VME) bus-based system utilizes Front Panel Data Port (FPDP) for high-speed data transfer. Data coming from physically different locations is referenced to several different ground potentials necessitating the need for a custom FPDP multiplexer. This paper discusses the data acquisition system configuration, the in-house designed 4-to-1 FPDP Input Multiplexing Module (FIMM), and future expansion plans.

  1. Ignition of beam plasma discharge in the electron beam experiment in space

    NASA Technical Reports Server (NTRS)

    Sasaki, S.; Kawashima, N.; Kuriki, K.; Yanagisawa, M.; Roberts, W. T.; Taylor, W. W. L.

    1985-01-01

    An ignition of beam plasma discharge (BPD) in space was observed in a neutral gas-electron beam interaction experiment by Space Shuttle/Spacelab-1 in 1983. An electron beam of 8 kV 100 mA was injected into a high dense nitrogen gas cloud of 10 to the 23rd molecules which was released during 100 msec from the Orbiter. The appearance of the beam and its surroundings observed by a low-light-level TV camera showed a local ignition of the beam plasma discharge in the gas cloud. The enhanced plasma production, generation of auroral emission, and associated wave emission were also detected by onboard diagnostic instruments.

  2. Hot-electron plasma formation and confinement in the tandem mirror experiment-upgrade

    SciTech Connect

    Ress, D.B.

    1988-06-01

    The tandem mirror experiment-upgrade (TMX-U) at the Lawrence Livermore National Laboratory (LLNL) is the first experiment to investigate the thermal-barrier tandem-mirror concept. One attractive feature of the tandem magnetic mirror as a commercial power reactor is that the fusion reactions occur in an easily accessible center-cell. On the other hand, complicated end-cells are necessary to provide magnetohydrodynamic (MHD) stability and improved particle confinement of the center-cell plasma. In these end-cells, enhanced confinement is achieved with a particular axial potential profile that is formed with electron-cyclotron range-of-frequency heating (ECRF heating, ECRH). By modifying the loss rates of electrons at spatially distinct locations within the end-cells, the ECRH can tailor the plasma potential profile in the desired fashion. Specifically, the thermal-barrier concept requires generation of a population of energetic electrons near the midplane of each end-cell. To be effective, the transverse (to the magnetic field) spatial structure of the hot-electron plasma must be fairly uniform. In this dissertation we characterize the spatial structure of the ECRH-generated plasma, and determine how the structure builds up in time. Furthermore, the plasma should efficiently absorb the ECRF power, and a large fraction of the electrons must be well confined near the end-cell midplane. Therefore, we also examine in detail the ECRH power balance, determining how the ECRF power is absorbed by the plasma, and the processes through which that power is confined and lost. 43 refs., 69 figs., 6 tabs.

  3. Design, development, and results from a charge-collector diagnostic for a toroidal electron plasma experiment.

    PubMed

    Pahari, Sambaran; Lachhvani, Lavkesh; Bajpai, Manu; Rathod, Karan; Yeole, Yogesh; Chattopadhyay, P K

    2015-08-01

    A suitable charge-collector has been designed and developed to estimate charge-content of electron plasmas in a Small Aspect Ratio Toroidal Experiment in a C-shaped trap (SMARTEX-C). The electrons are periodically injected and held in the trap with the aid of electrostatic end-fields and a toroidal magnetic field. After a preset "hold" time, the trapped charges are dumped onto a grounded collector (by gating it). As the charges flow along the magnetic field lines onto the collector, the integrated current gives the charge-content of the plasma at the instant of dump. In designing such a charge collector, several challenges peculiar to the geometry of the trap and the nature of the plasma had to be addressed. Instantaneous charge measurements synchronised with the E × B drift of the plasma, along with fast transit times of electrons to the collector (few 100 ns or less) (due to the low aspect ratio of the trap) essentially require fast gating of the collector. The resulting large capacitive transients alongside low charge content (few nC) of such plasmas further lead to increasing demands on response and sensitivity of the collector. Complete cancellation of such transients is shown to be possible, in principle, by including the return path in our measurement circuit but the "non-neutrality" of the plasma acts as a further impediment. Ultimately, appropriate shielding and measurement circuits allow us to (re)distribute the capacitance and delineate the paths of these currents, leading to effective cancellation of transients and marked improvement in sensitivity. Improved charge-collector has thus been used to successfully estimate the time evolution of total charge of the confined electron plasma in SMARTEX-C.

  4. Design, development, and results from a charge-collector diagnostic for a toroidal electron plasma experiment

    SciTech Connect

    Pahari, Sambaran; Lachhvani, Lavkesh Bajpai, Manu; Rathod, Karan; Yeole, Yogesh; Chattopadhyay, P. K.

    2015-08-15

    A suitable charge-collector has been designed and developed to estimate charge-content of electron plasmas in a Small Aspect Ratio Toroidal Experiment in a C-shaped trap (SMARTEX-C). The electrons are periodically injected and held in the trap with the aid of electrostatic end-fields and a toroidal magnetic field. After a preset “hold” time, the trapped charges are dumped onto a grounded collector (by gating it). As the charges flow along the magnetic field lines onto the collector, the integrated current gives the charge-content of the plasma at the instant of dump. In designing such a charge collector, several challenges peculiar to the geometry of the trap and the nature of the plasma had to be addressed. Instantaneous charge measurements synchronised with the E × B drift of the plasma, along with fast transit times of electrons to the collector (few 100 ns or less) (due to the low aspect ratio of the trap) essentially require fast gating of the collector. The resulting large capacitive transients alongside low charge content (few nC) of such plasmas further lead to increasing demands on response and sensitivity of the collector. Complete cancellation of such transients is shown to be possible, in principle, by including the return path in our measurement circuit but the “non-neutrality” of the plasma acts as a further impediment. Ultimately, appropriate shielding and measurement circuits allow us to (re)distribute the capacitance and delineate the paths of these currents, leading to effective cancellation of transients and marked improvement in sensitivity. Improved charge-collector has thus been used to successfully estimate the time evolution of total charge of the confined electron plasma in SMARTEX-C.

  5. The Charged Aerosol Release Experiment (Care II) to Study Artificial Dusty Plasmas in the Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Bernhardt, P. A.; Siefring, C. L.; Gatling, G.; Briczinski, S. J., Jr.; Vierinen, J.; Bhatt, A.; Holzworth, R. H., II; McCarthy, M.; Gustavsson, B.; La Hoz, C.; Latteck, R.

    2015-12-01

    A sounding rocket launched from Andoya, Norway in September 2015 carried 37 rocket motors and a multi-instrument daughter payload into the ionosphere to study the generation of plasma wave electric fields and ionospheric density disturbances by the high-speed injection of dust particles. The primary purpose of the CARE II mission is to validate the dress-particle theory of enhanced incoherent scatter from a dusty plasma and to validate models of plasma instabilities driven by high-speed charged particles. The CARE II chemical payload produces 66 kg of micron-sized dust particles composed of aluminium oxide. In addition to the dust, simple molecular combustion products such as N2, H2, CO2, CO, H20 and NO will be injected into the bottomside of the F-layer. Charging of the dust and ion charge exchange with the molecules yields plasma particles moving at hypersonic velocities. Streaming instabilities and shear electric fields causes plasma turbulence that can be detected using ground radars and in situ plasma instruments. The instrument payload was separated from the chemical release payload soon after launch to measure electric field vectors, electron and ion densities, and integrated electron densities from the rocket to the ground. The chemical release of high speed dust was directed upward on the downleg of the rocket trajectory to intersect the F-Layer. The instrument section was about 600 meters from the dust injection module at the release time. Ground HF and UHF radars were operated to detected scatter and refraction by the modified ionosphere. Optical instruments from airborne and ground observatories were used to map the dispersal of the dust using scattered sunlight. The plasma interactions are being simulated with both fluid and particle-in-cell (PIC) codes. CARE II is a follow-on to the CARE I rocket experiment conducted from Wallops Island Virginia in September 2009.

  6. Modeling and experiments on differential pumping in linear plasma generators operating at high gas flows

    SciTech Connect

    Eck, H. J. N. van; Koppers, W. R.; Rooij, G. J. van; Goedheer, W. J.; Cardozo, N. J. Lopes; Kleyn, A. W.; Engeln, R.; Schram, D. C.

    2009-03-15

    The direct simulation Monte Carlo (DSMC) method was used to investigate the efficiency of differential pumping in linear plasma generators operating at high gas flows. Skimmers are used to separate the neutrals from the plasma beam, which is guided from the source to the target by a strong axial magnetic field. In this way, the neutrals are prevented to reach the target region. The neutral flux to the target must be lower than the plasma flux to enable ITER relevant plasma-surface interaction (PSI) studies. It is therefore essential to control the neutral gas dynamics. The DSMC method was used to model the expansion of a hot gas in a low pressure vessel where a small discrepancy in shock position was found between the simulations and a well-established empirical formula. Two stage differential pumping was modeled and applied in the linear plasma devices Pilot-PSI and PLEXIS. In Pilot-PSI a factor of 4.5 pressure reduction for H{sub 2} has been demonstrated. Both simulations and experiments showed that the optimum skimmer position depends on the position of the shock and therefore shifts for different gas parameters. The shape of the skimmer has to be designed such that it has a minimum impact on the shock structure. A too large angle between the skimmer and the forward direction of the gas flow leads to an influence on the expansion structure. A pressure increase in front of the skimmer is formed and the flow of the plasma beam becomes obstructed. It has been shown that a skimmer with an angle around 53 deg. gives the best performance. The use of skimmers is implemented in the design of the large linear plasma generator Magnum-PSI. Here, a three stage differentially pumped vacuum system is used to reach low enough neutral pressures near the target, opening a door to PSI research in the ITER relevant regime.

  7. Experiments and Simulations of ITER-like Plasmas in Alcator C-Mod

    SciTech Connect

    .R. Wilson, C.E. Kessel, S. Wolfe, I.H. Hutchinson, P. Bonoli, C. Fiore, A.E. Hubbard, J. Hughes, Y. Lin, Y. Ma, D. Mikkelsen, M. Reinke, S. Scott, A.C.C. Sips, S. Wukitch and the C-Mod Team

    2010-09-24

    Alcator C-Mod is performing ITER-like experiments to benchmark and verify projections to 15 MA ELMy H-mode Inductive ITER discharges. The main focus has been on the transient ramp phases. The plasma current in C-Mod is 1.3 MA and toroidal field is 5.4 T. Both Ohmic and ion cyclotron (ICRF) heated discharges are examined. Plasma current rampup experiments have demonstrated that (ICRF and LH) heating in the rise phase can save voltseconds (V-s), as was predicted for ITER by simulations, but showed that the ICRF had no effect on the current profile versus Ohmic discharges. Rampdown experiments show an overcurrent in the Ohmic coil (OH) at the H to L transition, which can be mitigated by remaining in H-mode into the rampdown. Experiments have shown that when the EDA H-mode is preserved well into the rampdown phase, the density and temperature pedestal heights decrease during the plasma current rampdown. Simulations of the full C-Mod discharges have been done with the Tokamak Simulation Code (TSC) and the Coppi-Tang energy transport model is used with modified settings to provide the best fit to the experimental electron temperature profile. Other transport models have been examined also. __________________________________________________

  8. Current Status of MPPE (Mercury Plasma Particle Experiment) on BepiColombo/MMO

    NASA Astrophysics Data System (ADS)

    Saito, Yoshifumi; Hirahara, Masafumi; Barabash, Stas; Delcourt, Dominique; André, Nicolas; Takashima, Takeshi; Asamura, Kazushi

    2015-04-01

    Mercury's plasma/particle environment has gradually become clear thanks to the new observations made by MESSENGER spacecraft orbiting around Mercury. However, it is also true that many questions will be left unsolved. In order to elucidate the detailed plasma structure and dynamics around Mercury, an orbiter BepiColombo MMO (Mercury Magnetospheric Orbiter) is going to be launched in 2016 as a joint mission between ESA and ISAS/JAXA. Mercury Plasma/Particle Experiment (MPPE) is a comprehensive instrument package for plasma, high-energy particle and energetic neutral atom measurements. It consists of 7 sensors: two Mercury Electron Analyzers (MEA1 and MEA2), Mercury Ion Analyzer (MIA), Mass Spectrum Analyzer (MSA), High Energy Particle instrument for electron (HEP-ele), High Energy Particle instrument for ion (HEP-ion), and Energetic Neutrals Analyzer (ENA). Currently, the MPPE sensors are on the MMO spacecraft under system integration test at ISAS/JAXA (Institute of Space and Astronautical Science / Japan Aerospace Exploration Agency). Evaluation of the sensor calibration data and the final check of the onboard processing software are being made in order to realize the flawless future plasma/particle observations around Mercury.

  9. Measurements of Plasma Power Losses in the C-2 Field-Reversed Configuration Experiment

    NASA Astrophysics Data System (ADS)

    Korepanov, Sergey; Smirnov, Artem; Garate, Eusebio; Donin, Alexandr; Kondakov, Alexey; Singatulin, Shavkat

    2013-10-01

    A high-confinement operating regime with plasma lifetimes significantly exceeding past empirical scaling laws was recently obtained by combining plasma gun edge biasing and tangential Neutral Beam Injection in the C-2 field-reversed configuration (FRC) experiment. To analyze the power balance in C-2, two new diagnostic instruments - the pyroelectric (PE) and infrared (IR) bolometers - were developed. The PE bolometer, designed to operate in the incident power density range from 0.1-100 W/cm2, is used to measure the radial power loss, which is dominated by charge-exchange neutrals and radiation. The IR bolometer, which measures power irradiated onto a thin metal foil inserted in the plasma, is designed for the power density range from 0.5-5 kW/cm2. The IR bolometer is used to measure the axial power loss from the plasma near the end divertors. The maximum measurable pulse duration of ~ 10 ms is limited by the heat capacitance of the IR detector. Both detectors have time resolution of about 10-100 μs and were calibrated in absolute units using a high power neutral beam. We present the results of first direct measurements of axial and radial plasma power losses in C-2.

  10. An experiment to measure the electron ion thermal equilibration rate in a strongly coupled plasma

    NASA Astrophysics Data System (ADS)

    Taccetti, J. M.; Shurter, R. P.; Roberts, J. P.; Benage, J. F.; Graden, B.; Haberle, B.; Murillo, M. S.; Vigil, B.; Wysocki, F. J.

    2006-04-01

    We present the most recent results from an experiment aimed at obtaining the temperature equilibration rate between ions and electrons in a strongly coupled plasma by directly measuring the temperature of each component. The plasma is formed by heating a sonic gas jet with a 10 ps laser pulse. The electrons are preferentially heated by the short pulse laser (we are aiming for Te ~ 100 eV), while the ions, after undergoing very rapid (sub-ps timescale) disorder-induced heating, should only reach a temperature of 10-15 eV. This results in a strongly coupled ion plasma with a Γii ~ 3-5. We plan to measure the electron and ion temperatures of the resulting plasma independently during and after heating, using collective Thomson scattering for electrons and a high-resolution x-ray spectrometer for the ions (measuring Doppler-broadened absorption lines). Theory indicates that the equilibration rate could be significantly lower than that given by the usual weakly coupled model (Landau-Spitzer) due to coupled collective modes present in the dense plasma.

  11. Initial operation of a large-scale Plasma Source Ion Implantation experiment

    SciTech Connect

    Wood, B.P.; Henins, I.; Gribble, R.J.; Reass, W.A.; Faehl, R.J.; Nastasi, M.A.; Rej, D.J.

    1993-10-01

    In Plasma Source Ion Implantation (PSII), a workpiece to be implanted is immersed in a weakly ionized plasma and pulsed to a high negative voltage. Plasma ions are accelerated toward the workpiece and implanted in its surface. Experimental PSII results reported in the literature have been for small workpieces. A large scale PSII experiment has recently been assembled at Los Alamos, in which stainless steel and aluminum workpieces with surface areas over 4 m{sup 2} have been implanted in a 1.5 m-diameter, 4.6 m-length cylindrical vacuum chamber. Initial implants have been performed at 50 kV with 20 {mu}s pulses of 53 A peak current, repeated at 500 Hz, although the pulse modulator will eventually supply 120 kV pulses of 60 A peak current at 2 kHz. A 1,000 W, 13.56 MHz capacitively-coupled source produces nitrogen plasma densities in the 10{sup 15} m{sup {minus}3} range at neutral pressures as low as 0.02 mtorr. A variety of antenna configurations have been tried, with and without axial magnetic fields of up to 60 gauss. Measurements of sheath expansion, modulator voltage and current, and plasma density fill-in following a pulse are presented. The authors consider secondary electron emission, x-ray production, workpiece arcing, implant conformality, and workpiece and chamber heating.

  12. Experimental observation of plasma formation and current transfer in fine wire expansion experiments.

    SciTech Connect

    Deeney, Christopher E.; Duselis, Peter U. (Cornell University, Ithaca, NY); Kusse, Bruce; Sinars, Daniel Brian

    2003-05-01

    When several kA pulses are passed through single, fine 25 {micro}m diameter wires, the wire material heats, melts, vaporizes and expands. Initially the voltage across--and current through--a wire increases until an abrupt voltage collapse occurs. After this collapse the voltage remains at a relative small value while the current continues to increase. In order to understand how this early time behavior may affect the subsequent implosion, small-scale experiments at Cornell University's Laboratory of Plasma Studies concentrated on diagnosing expanding single wire dynamics. X-ray backlighting, interferometry and Schlieren imaging as well as current and voltage measurements have been employed. The voltage collapse has been attributed to the formation of plasma around the wire and a transfer of current to this highly conducting coronal plasma. Interferometry has confirmed the plasma formation, but the current transfer has only been postulated. Subsequent experiments on the Z-Facility at Sandia National Laboratories have produced impressive x-ray yields etc.

  13. Working group report on beam plasmas, electronic propulsion, and active experiments using beams

    NASA Technical Reports Server (NTRS)

    Dawson, J. M.; Eastman, T.; Gabriel, S.; Hawkins, J.; Matossian, J.; Raitt, J.; Reeves, G.; Sasaki, S.; Szuszczewicz, E.; Winkler, J. R.

    1986-01-01

    The JPL Workshop addressed a number of plasma issues that bear on advanced spaceborne technology for the years 2000 and beyond. Primary interest was on the permanently manned space station with a focus on identifying environmentally related issues requiring early clarification by spaceborne plasma experimentation. The Beams Working Group focused on environmentally related threats that platform operations could have on the conduct and integrity of spaceborne beam experiments and vice versa. Considerations were to include particle beams and plumes. For purposes of definition it was agreed that the term particle beams described a directed flow of charged or neutral particles allowing single-particle trajectories to represent the characteristics of the beam and its propagation. On the other hand, the word plume was adopted to describe a multidimensional flow (or expansion) of a plasma or neutral gas cloud. Within the framework of these definitions, experiment categories included: (1) Neutral- and charged-particle beam propagation, with considerations extending to high powers and currents. (2) Evolution and dynamics of naturally occurring and man-made plasma and neutral gas clouds. In both categories, scientific interest focused on interactions with the ambient geoplasma and the evolution of particle densities, energy distribution functions, waves, and fields.

  14. A design of experiment study of plasma sprayed alumina-titania coatings

    SciTech Connect

    Steeper, T.J.; Varacalle, D.J. Jr.; Wilson, G.C.; Riggs, W.L. II; Rotolico, A.J.; Nerz, J.E.

    1992-08-01

    An experimental study of the plasma spraying of alumina-titania powder is presented in this paper. This powder system is being used to fabricate heater tubes that emulate nuclear fuel tubes for use in thermal-hydraulic testing. Coating experiments were conducted using a Taguchi fractional-factorial design parametric study. Operating parameters were varied around the typical spray parameters in a systematic design of experiments in order to display the range of plasma processing conditions and their effect on the resultant coating. The coatings were characterized by hardness and electrical tests, image analysis, and optical metallography. Coating qualities are discussed with respect to dielectric strength, hardness, porosity, surface roughness, deposition efficiency, and microstructure. The attributes of the coatings are correlated with the changes in operating parameters.

  15. A design of experiment study of plasma sprayed alumina-titania coatings

    SciTech Connect

    Steeper, T.J. and Co., Aiken, SC . Savannah River Lab.); Varacalle, D.J. Jr.; Wilson, G.C. ); Riggs, W.L. II ); Rotolico, A.J.; Nerz, J.E. )

    1992-01-01

    An experimental study of the plasma spraying of alumina-titania powder is presented in this paper. This powder system is being used to fabricate heater tubes that emulate nuclear fuel tubes for use in thermal-hydraulic testing. Coating experiments were conducted using a Taguchi fractional-factorial design parametric study. Operating parameters were varied around the typical spray parameters in a systematic design of experiments in order to display the range of plasma processing conditions and their effect on the resultant coating. The coatings were characterized by hardness and electrical tests, image analysis, and optical metallography. Coating qualities are discussed with respect to dielectric strength, hardness, porosity, surface roughness, deposition efficiency, and microstructure. The attributes of the coatings are correlated with the changes in operating parameters.

  16. Experiment attributes to establish tube with twisted tape insert performance cooling plasma facing components

    SciTech Connect

    Clark, Emily; Ramirez, Emilio; Ruggles, Art E.; Griffard, Cory

    2015-08-18

    The modeling capability for tubes with twisted tape inserts is reviewed with reference to the application of cooling plasma facing components in magnetic confinement fusion devices. The history of experiments examining the cooling performance of tubes with twisted tape inserts is reviewed with emphasis on the manner of heating, flow stability limits and the details of the test section and fluid delivery system. Models for heat transfer, burnout, and onset of net vapor generation in straight tube flows and tube with twisted tape are compared. As a result, the gaps in knowledge required to establish performance limits of the plasma facing components are identified and attributes of an experiment to close those gaps are presented.

  17. The electric field structure of auroral arcs as determined from barium plasma injection experiments

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.

    1981-01-01

    Barium plasma injection experiments have revealed a number of features of electric fields in and near auroral forms extending from a few hundred to many thousands of km in altitude. There is evidence for V-type potential structures over some auroras, but not in others. For some auroral arcs, large E fields are found at ionospheric altitudes outside the arc but the E field inside the arc is near zero. In a few other auroras, most recently one investigated in an experiment conducted from Poker Flat on March 22, 1980, large, rapidly fluctuating E fields were detected by barium plasma near 600 km altitude. These E fields suggest that the motion of auroral rays can be an effect of low-altitude electric fields, or that V-type potential structures may be found at low altitudes.

  18. Optical pyrometer system for collisionless shock experiments in high-power laser-produced plasmas.

    PubMed

    Morita, T; Sakawa, Y; Kuramitsu, Y; Dono, S; Ide, T; Shibata, S; Aoki, H; Tanji, H; Sano, T; Shiroshita, A; Waugh, J N; Gregory, C D; Woolsey, N C; Takabe, H

    2012-10-01

    A temporally and spatially resolved optical pyrometer system has been fielded on Gekko XII experiments. The system is based on the self-emission measurements with a gated optical imager (GOI) and a streaked optical pyrometer (SOP). Both detectors measure the intensity of the self-emission from laser-produced plasmas at the wavelength of 450 nm with a bandpass filter with a width of ~10 nm in FWHM. The measurements were calibrated with different methods, and both results agreed with each other within 30% as previously reported [T. Morita et al., Astrophys. Space Sci. 336, 283 (2011)]. As a tool for measuring the properties of low-density plasmas, the system is applicable for the measurements of the electron temperature and density in collisionless shock experiments [Y. Kuramitsu et al., Phys. Rev. Lett. 106, 175002 (2011)]. PMID:23126856

  19. Optical pyrometer system for collisionless shock experiments in high-power laser-produced plasmas

    SciTech Connect

    Morita, T.; Sakawa, Y.; Kuramitsu, Y.; Sano, T.; Takabe, H.; Dono, S.; Ide, T.; Tanji, H.; Shiroshita, A.; Shibata, S.; Aoki, H.; Waugh, J. N.; Woolsey, N. C.; Gregory, C. D.

    2012-10-15

    A temporally and spatially resolved optical pyrometer system has been fielded on Gekko XII experiments. The system is based on the self-emission measurements with a gated optical imager (GOI) and a streaked optical pyrometer (SOP). Both detectors measure the intensity of the self-emission from laser-produced plasmas at the wavelength of 450 nm with a bandpass filter with a width of {approx}10 nm in FWHM. The measurements were calibrated with different methods, and both results agreed with each other within 30% as previously reported [T. Morita et al., Astrophys. Space Sci. 336, 283 (2011)]. As a tool for measuring the properties of low-density plasmas, the system is applicable for the measurements of the electron temperature and density in collisionless shock experiments [Y. Kuramitsu et al., Phys. Rev. Lett. 106, 175002 (2011)].

  20. Hot electron plasma equilibrium and stability in the Constance B mirror experiment

    SciTech Connect

    Chen, Xing

    1988-04-01

    An experimental study of the equilibrium and macroscopic stability property of an electron cyclotron resonance heating (ECRH) generated plasma in a minimum-B mirror is presented. The Constance B mirror is a single cell quadrupole magnetic mirror in which high beta (..beta.. less than or equal to 0.3) hot electron plasmas (T/sub e/approx. =400 keV) are created with up to 4 kW of ECRH power. The plasma equilibrium profile is hollow and resembles the baseball seam geometry of the magnet which provides the confining magnetic field. This configuration coincides with the drift orbit of deeply trapped particles. The on-axis hollowness of the hot electron density profile is 50 /+-/ 10%, and the pressure profile is at least as hollow as, if not more than, the hot electron density profile. The hollow plasma equilibrium is macroscopically stable and generated in all the experimental conditions in which the machine has been operated. The hollowness of the plasma pressure profile is not limited by the marginal stability condition. Small macroscopic plasma fluctuations in the range of the hot electron curvature drift frequency sometimes occur but their growth rate is small (..omega../sub i//..omega../sub r/ less than or equal to 10/sup -2/) and saturate at very low level (deltaB//bar B/ less than or equal to 10/sup -3/). Particle drift reversal is predicted to occur for the model pressure profile which best fits the experimental data under the typical operating conditions. No strong instability is observed when the plasma is near the drift reversal parameter regime, despite a theoretical prediction of instability under such conditions. The experiment shows that the cold electron population has no stabilizing effect to the hot electrons, which disagrees with current hot electron stability theories and results of previous maximum-B experiments. A theoretical analysis using MHD theory shows that the compressibility can stabilize a plasma with a hollowness of 20--30% in the

  1. Electron Bunch Length Measurements in the E-167 Plasma Wakefield Experiment

    SciTech Connect

    Blumenfeld, I.; Auerbach, D.; Berry, M.; Clayton, C.E.; Decker, F.J.; Hogan, M.J.; Huang, Cheng-Kun; Ischebeck, R.; Iverson, R.; Johnson, D.; Joshi, C.; Katsouleas, T.; Kirby, N.; Lu, Wei; Marsh, K.A.; Mori, W.B.; Muggli, P.; Oz, E.; Siemann, R.H.; Walz, D.; Zacherl, W.; /SLAC /UCLA /Southern California U.

    2007-03-27

    Bunch length is of prime importance to beam driven plasma wakefield acceleration experiments due to its inverse relationship to the amplitude of the accelerating wake. We present here a summary of work done by the E167 collaboration measuring the SLAC ultra-short bunches via autocorrelation of coherent transition radiation. We have studied material transmission properties and improved our autocorrelation traces using materials with better spectral characteristics.

  2. Electron Gyro-scale Fluctuation Measurements in National Spherical Torus Experiment H-mode Plasmas

    SciTech Connect

    Smith, D R; Lee, W; Mazzucato, E; Park, H K; Bell, R E; Domier, C W; LeBlanc, B P; Levinton, F M; Luhmann, N C; Menard, J E

    2009-08-10

    A collective scattering system has measured electron gyro-scale fluctuations in National Spherical Torus Experiment (NSTX) H-mode plasmas to investigate electron temperature gradient (ETG) turbulence. Observations and results pertaining to fluctuation measurements in ETGstable regimes, the toroidal field scaling of fluctuation amplitudes, the relation between between fluctuation amplitudes and transport quantities, and fluctuation magnitudes and k-spectra are presented. Collectively, the measurements provide insight and guidance for understanding ETG turbulence and anomalous electron thermal transport.

  3. Measurements of Prompt and MHD-Induced Fast Ion Loss from National Spherical Torus Experiment Plasmas

    SciTech Connect

    D.S. Darrow; S.S. Medley; A.L. Roquemore; W.W. Heidbrink; A. Alekseyev; F.E. Cecil; J. Egedal; V.Ya. Goloborod'ko; N.N. Gorelenkov; M. Isobe; S. Kaye; M. Miah; F. Paoletti; M.H. Redi; S.N. Reznik; A. Rosenberg; R. White; D. Wyatt; V.A. Yavorskij

    2002-10-15

    A range of effects may make fast ion confinement in spherical tokamaks worse than in conventional aspect ratio tokamaks. Data from neutron detectors, a neutral particle analyzer, and a fast ion loss diagnostic on the National Spherical Torus Experiment (NSTX) indicate that neutral beam ion confinement is consistent with classical expectations in quiescent plasmas, within the {approx}25% errors of measurement. However, fast ion confinement in NSTX is frequently affected by magnetohydrodynamic (MHD) activity, and the effect of MHD can be quite strong.

  4. In situ measurements of ionospheric plasma turbulence over five frequency decades: Heritage flight of the Plasma Local Anomalous Noise Experiment (PLANE)

    NASA Astrophysics Data System (ADS)

    Habash Krause, L.; Enloe, C. L.; McHarg, M. G.

    2013-12-01

    Observations of ionospheric plasma density and frequency-dependent broadband plasma turbulence made during the heritage flight of the Plasma Local Anomalous Noise Experiment (PLANE) are presented. Rather than record high frequency time series data, the experiment was designed to record Power Spectral Distributions (PSDs) in five decadal frequency bins with upper limits ranging from 1.0 Hz to 10 kHz. Additionally, PLANE was designed distinguish turbulence in the ambient plasma from that local to the spacecraft. The instrument consists of two retarding potential analyzers (RPAs) connected together via a feedback loop to force one analyzer into the I-V trace retardation region at all times. Fluctuations in this measurement are believed to be ambient only as the RPA's voltage would be too high for locally turbulent plasma to surmount the potential barrier, which is nominally at ram energy. The instrument requires pointing along the spacecraft's ram velocity vector to make this measurement, thus requiring stabilization in pitch and yaw. During PLANE's heritage flight, though the satellite's attitude control system failed early in the mission, plasma data were collected during opportune times in which the instrument rotated into and out of the ram. Observations of plasma density and PSDs of high frequency plasma turbulence were recorded on several occasions. Additionally, a plasma source onboard the satellite was used to generate artificial plasma turbulence, and the PLANE data observed periodic structure presumably associated with the rotation of the spacecraft during these source firings. A brief comparison with other high frequency in situ plasma instruments is presented.

  5. ELM simulation experiments using transient heat and particle load produced by a magnetized coaxial plasma gun

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

    It is considered that thermal transient events such as type I edge-localized modes (ELMs) and disruptions will limit the lifetime of plasma-facing components (PFCs) in ITER. It is predicted that the heat load onto the PFCs during type I ELMs in ITER is 0.2-2MJ/m2 with pulse length of ~0.1-1ms. We have investigated interaction between transient heat and particle load and the PFCs by using a magnetized coaxial plasma gun (MCPG) at University of Hyogo. In the experiment, a pulsed plasma with duration of ~0.5ms, incident ion energy of ~30eV, and surface absorbed energy density of ~0.3-0.7MJ/m2 was produced by the MCPG. However, no melting occurred on a tungsten surface exposed to a single plasma pulse of ~0.7MJ/m2, while cracks clearly appeared at the edge part of the W surface. Thus, we have recently started to improve the performance of the MCPG in order to investigate melt layer dynamics of a tungsten surface such as vapor cloud formation. In the modified MCPG, the capacitor bank energy for the plasma discharge is increased from 24.5 kJ to 144 kJ. In the preliminary experiments, the plasmoid with duration of ~0.6 ms, incident ion energy of ~ 40 eV, and the surface absorbed energy density of ~2 MJ/m2 was successfully produced at the gun voltage of 6 kV.

  6. Soft x-ray studies of plasma-focus pinch structures in PF-1000U experiments

    NASA Astrophysics Data System (ADS)

    Sadowski, M. J.; Paduch, M.; Skladnik-Sadowska, E.; Surala, W.; Zaloga, D.; Miklaszewski, R.; Zielinska, E.; Tomaszewski, K.

    2015-10-01

    This work reports on recent experiments performed at the modernized PF-1000U plasma-focus facility. In contrast to earlier studies the main attention was focussed on measurements of the soft x-ray emission. Detailed time-integrated x-ray measurements, carried out using filtered pinhole cameras with sensitive x-ray films, are presented and analysed. The fine structure of the collapsing current sheath and dense pinch column is investigated. Observations of ‘plasma filaments’ are discussed and compared with those from the old POSEIDON facility. New results are time-integrated x-ray images of PF-1000U discharges with additional gas puffing, which in many cases show distinct plasma filaments and/or ‘hot spots’ formed inside the dense pinch column. The formation of such ‘hot-spots’ is explained by necking and breaking of the plasma filaments. Results of time-resolved x-ray measurements, performed outside the experimental chamber by means of scintillation probes, and inside with PIN-diodes placed behind pinholes and absorption filters, are also presented Time-resolved measurements, carried out using an old XUV framing-camera and a new soft x-ray four-frame camera (SXRFFC), are also presented and discussed. Correlations of the time-integrated x-ray images (of plasma filaments and hot spots) with time-resolved x-ray signals are discussed. The hypothesis that plasma-current filaments appear in almost all PF-type discharges is supported by pictures of radial erosion tracks on the anode front-plate after many discharges.

  7. Application of imaging plate to x-ray imaging and spectroscopy in laser plasma experiments

    SciTech Connect

    Izumi, N; Snavely, R; Gregori, G; Koch, J A; Park, H; Remington, B A

    2006-04-25

    We report recent progress of x-ray diagnostic techniques in laser plasma experiment with using imaging plates. Imaging plate is a photo-stimulable phosphor screen (BaF(Br0.85,10.15):Eu{sup 2+}) deposited on flexible metal or plastic substrate. We applied the imaging plate to x-ray microscopy in laser fusion experiment experiments. Self-emission x-ray images of imploded core were obtained successfully with using imaging plate and high magnification target mounted pinhole arrays. The imaging plates were applied also in ultra-intense laser experiment at the Rutherford Appleton Laboratory. Small samarium foil was irradiated by high intensity laser pulse from the Vulcan laser system. The k shell x-rays from the foil ({approx}40keV) was used as a line x-ray source for microscopic radiography. Performance of imaging plate on high-energy x-ray backlit radiography was demonstrated by imaging sinusoidal grooves of 6um amplitude on a Au foil. Detailed spectrum of k shell x-ray from Cu embedded foil target was successfully observed by fully coupling imaging plate with a highly ordered pyrolytic graphite crystal spectrometer. The performances of the imaging plates evaluated in actual laser plasma experiments will be presented.

  8. Experience of stress in childhood negatively correlates with plasma oxytocin concentration in adult men.

    PubMed

    Opacka-Juffry, Jolanta; Mohiyeddini, Changiz

    2012-01-01

    Early life experience is known to affect responses to stress in adulthood. Adverse experience in childhood and/or adolescence sensitises to life events that precipitate depression in later life. Published evidence suggests a relationship between depression and oxytocin (OT), but the extent to which early life experience influences OT disposition in adulthood deserves further exploration. This study hypothesised that early life stress (ELS) has a long-term negative effect on OT system activity. The study was performed on 90 male volunteers (18-56 years; mean ± standard deviation = 27.7 ± 7.09 years). Several questionnaires were used to assess: health, early life stressful experiences in childhood (ELS-C, up to 12 years) and early life stressful adolescence (13-18 years), recent stressful life events, depressive symptoms, state-trait anxiety and social desirability. Plasma OT concentration was estimated by means of a competitive enzyme immunoassay. Lower OT concentrations were significantly associated with higher levels of ELS-C (p < 0.01), and with depressive symptoms and trait anxiety (both p < 0.05). The interaction between ELS-C and trait anxiety was significant (p < 0.05), indicating that the link between ELS-C and plasma OT concentration is moderated by trait anxiety. These results contribute to the evidence that early life adverse experience is negatively associated with OT system activity in adulthood, and offer further insight into mediator and moderator effects on this link.

  9. Beyond benchmarking—how experiments and simulations can work together in plasma physics

    NASA Astrophysics Data System (ADS)

    Greenwald, Martin

    2004-12-01

    There has been dramatic progress in the scope and power of plasma simulations in recent years; and because codes are generally cheaper to write, to run and to diagnose than experiments, they have a well-recognized potential to extend our understanding of complex phenomena like plasma turbulence. However, simulations are imperfect models for physical reality and can be trusted only so far as they demonstrate agreement, without bias, with experimental results. This "validation" process tests the correctness and completeness of the physical model along with the assumptions and simplifications required for solution. At the same time, it must be understood that experimental measurements are almost always incomplete and subject to significant uncertainties and errors. For optimum scientific progress, simulations and experiments must be seen as complementary not competitive approaches. We need experiments dedicated to answering critical questions raised by the simulations, which examine the validity of models and which explicitly test their assumptions. A premium should be placed on ongoing collaborations which are open and candid about the sources of error and the strengths and weaknesses of each approach. Ultimately both experiments and simulation have much to gain by adopting an approach of co-development, where simulations are continuously and carefully compared to experimental data and where experiments are guided by the results of simulations.

  10. Laser-induced fluorescence measurements on plasma science experiments at PPPL

    SciTech Connect

    Koepke, Mark

    2011-12-20

    Collaborative research between WVU and PPPL was carried out at WVU for the purpose of incorporating the sophisticated diagnostic technique known as laser-induced fluorescence (LIF) in the Paul-Trap Simulation Experiment (PTSX) at PPPL. WVU assembled a LIF system at WVU, transported it to PPPL, helped make LIF experiments on the PTSX device, participated in PTSX science, and trained PPPL staff in LIF techniques. In summary, WVU refurbished a non-operational LIF system being loaned from University of Maryland to PPPL and, by doing so, provided PPPL with additional diagnostic capability for its PTSX device and other General Plasma Science experiments. WVU students, staff, and faculty will visit PPPL to collaborate on PTSX experiments in the future.

  11. Plasma physics and environmental perturbation laboratory. [magnetospheric experiments from space shuttle

    NASA Technical Reports Server (NTRS)

    Vogl, J. L.

    1973-01-01

    Current work aimed at identifying the active magnetospheric experiments that can be performed from the Space Shuttle, and designing a laboratory to carry out these experiments is described. The laboratory, known as the PPEPL (Plasma Physics and Environmental Perturbation Laboratory) consists of 35-ft pallet of instruments connected to a 25-ft pressurized control module. The systems deployed from the pallet are two 50-m booms, two subsatellites, a high-power transmitter, a multipurpose accelerator, a set of deployable canisters, and a gimbaled instrument platform. Missions are planned to last seven days, during which two scientists will carry out experiments from within the pressurized module. The type of experiments to be performed are outlined.

  12. RETURN TO DIVISION IA FOOTBALL FOLLOWING A 1ST METATARSOPHALANGEAL JOINT DORSAL DISLOCATION

    PubMed Central

    Cook, Chad; Zarzour, Hap; Moorman, Claude T.

    2010-01-01

    Background. Although rare in occurrence, a dorsal dislocation of the 1st metatarsophalangeal (MTP) joint has been successfully treated using surgical and/or non-operative treatment. No descriptions of conservative intervention following a dorsal dislocation of the MTP joint in an athlete participating in a high contact sport are present in the literature. Objectives. The purpose of this case report is to describe the intervention and clinical reasoning during the rehabilitative process of a collegiate football player diagnosed with a 1st MTP joint dorsal dislocation. The plan of care and return to play criteria used for this athlete are presented. Case Description. The case involved a 19-year-old male Division IA football player, who suffered a traumatic dorsal dislocation of the 1st MTP joint during practice. The dislocation was initially treated on-site by closed reduction. Non-operative management included immobilization, therapeutic exercises, non-steroidal anti-inflammatories, manual treatment, modalities, prophylactic athletic taping, gait training, and a sport specific progression program for full return to Division IA football. Outcomes. Discharge from physical therapy occurred after six weeks of treatment. At discharge, no significant deviations existed during running, burst, and agility related drills. At a six-month follow-up, the patient reported full return to all football activities including contact drills without restrictions. Discussion. This case describes an effective six-week rehabilitation intervention for a collegiate football player who sustained a traumatic great toe dorsal dislocation. Further study is suggested to evaluate the intervention strategies and timeframe for return to contact sports. PMID:21589669

  13. Experiments on the interaction of heavy-ion beams with dense plasmas

    SciTech Connect

    Stoeckl, C.; Roth, M.; Suess, W.; Wetzler, H; Seelig, W.; Kulish, M.; Spiller, P.; Jacoby, J.; Hoffmann, D.H.H.

    1997-03-01

    Gas discharge plasma targets were used for energy loss and charge state measurements of fast heavy ions 5 MeV/u < E{sub kin} < 10 MeV/u in a regime of electron density and temperature up to 10{sup 19}cm{sup -3} and 20 eV, respectively. Progress has been achieved in the understanding of charge exchange processes in fully ionized hydrogen plasma. An improved model that has taken excitation-autoionization processes into account has removed some of the discrepancies of previous theoretical descriptions. Furthermore, the energy loss of the ion beam serves as an excellent diagnostic tool for measuring the electron density in partially ionized plasmas such as argon. The experience with these methods will be used in the future to diagnose dense laser-produced plasmas. A setup with a 5-GW neodymium-glass laser, currently under construction, will provide access to density ranges up to 10{sup 21} cm{sup -3} and temperatures > 100 eV. 13 refs., 7 figs.

  14. Feasibility of an experiment to measure stopping powers in solid-density deuterium plasmas at OMEGA

    NASA Astrophysics Data System (ADS)

    Lahmann, B.; Rinderknecht, H. G.; Zylstra, A. B.; Frenje, J. A.; Li, C. K.; Seguin, F. H.; Petrasso, R. D.; Regan, S.; Sangster, C.; Graziani, F.; Collins, G. W.; Rygg, J. R.; Grabowski, P.; Glenzer, S.; Keiter, P.

    2014-10-01

    An experimental design to measure the stopping powers of charged-particles through solid-density, fully-ionized deuterium plasmas at temperatures around 10 eV is investigated. Stopping power in this regime is crucial to the understanding of alpha-heating and burn in Internal Confinement Fusion. Recent work by A.B. Zylstra et al. on the OMEGA laser facility has demonstrated such measurements of stopping power in partially ionized Be plasmas, by measuring the downshift of D3He-protons in an isochorically heated sample. As noted in their work, the effects of partial ionization are not well understood; however such effects are not applicable to hydrogenic fuels, for which the plasmas are expected to be fully ionized. This study will consider the viability of isochorically or shock heating a target to Warm Dense Matter conditions using a platform similar to the planar cryogenic system described by S.P. Regan et al. Plasma properties will be determined by x-ray Thomson scattering while stopping powers will be inferred through measuring downshift of either DD-protons, D3He-protons or D3He-alphas, the latter of which is directly applicable to the stopping of DT-alphas in ignition experiments. This work was supported in part by the U.S. DOE, NLUF, LLE, and LLNL.

  15. Inward radial transport in differentially rotated plasma discs formed in z-pinch experiments

    NASA Astrophysics Data System (ADS)

    Lebedev, Sergey; Bennett, M.; Swadling, G. F.; Suttle, L.; Blackman, E.; Burdiak, G.; Chittenden, J. P.; Ciardi, A.; Drake, R. P.; Frank, A.; Hall, G. N.; Hare, J.; Patankar, S.; Smith, R. A.; Suzuki-Vidal, F.

    2014-10-01

    We will present experimental results showing the development of instabilities and an inward transport of matter in a differentially rotating supersonic plasma disc with dimensionless parameters relevant to modeling physics of astrophysical discs. The converging off-axis plasma flow forming the disc is produced by ablation of wires in a cylindrical wire array z-pinch (1.4 MA, 250 ns) combined with a cusp magnetic field, and the rotating disc is supported in equilibrium by the ram pressure of the flow. The radial profile of rotation velocity in the disc is measured using Doppler shifts of the ion feature of Thomson scattering spectra, while the broadening of the spectra yields the plasma temperature. The evolution of the disc structure is observed with multi-frame XUV and optical cameras, and the plasma density is measured using end-on laser interferometry. The Reynolds number in the disc is sufficiently large (>105) to allow development of turbulence on the time-scale of the experiment, and the observed inward transport of matter with the growth of small scale structures suggests that turbulence is responsible for the transport.

  16. Helicon Plasma Injector and Ion Cyclotron Acceleration Development in the VASIMR Experiment

    NASA Technical Reports Server (NTRS)

    Squire, Jared P.; Chang, Franklin R.; Jacobson, Verlin T.; McCaskill, Greg E.; Bengtson, Roger D.; Goulding, Richard H.

    2000-01-01

    In the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) radio frequency (rf) waves both produce the plasma and then accelerate the ions. The plasma production is done by action of helicon waves. These waves are circular polarized waves in the direction of the electron gyromotion. The ion acceleration is performed by ion cyclotron resonant frequency (ICRF) acceleration. The Advanced Space Propulsion Laboratory (ASPL) is actively developing efficient helicon plasma production and ICRF acceleration. The VASIMR experimental device at the ASPL is called VX-10. It is configured to demonstrate the plasma production and acceleration at the 10kW level to support a space flight demonstration design. The VX-10 consists of three electromagnets integrated into a vacuum chamber that produce magnetic fields up to 0.5 Tesla. Magnetic field shaping is achieved by independent magnet current control and placement of the magnets. We have generated both helium and hydrogen high density (>10(exp 18) cu m) discharges with the helicon source. ICRF experiments are underway. This paper describes the VX-10 device, presents recent results and discusses future plans.

  17. Broadband Plasma-Sprayed Anti-reflection Coating for Millimeter-Wave Astrophysics Experiments

    NASA Astrophysics Data System (ADS)

    Jeong, O.; Lee, A.; Raum, C.; Suzuki, A.

    2016-08-01

    We have developed a plasma-sprayed anti-reflection (AR) coating technology for millimeter-wave astrophysics experiments with cryogenic optics which achieves minimal dissipative loss and broad bandwidth and is easily and accurately applied. Plasma spraying is a coating process through which melted or heated materials are sprayed onto a substrate. The dielectric constants of the plasma-sprayed coatings were tuned between 2.7 and 7.9 by mixing hollow ceramic microspheres with alumina powder as the base material and varying the plasma energy of the spray. By spraying low loss ceramic materials with a tunable dielectric constant, we can apply multiple layers of AR coating for broadband millimeter-wave detection. At 300 K, we achieved a fractional bandwidth of 106 over 90% transmission using a three-layer AR coating. Applying ceramic coatings on ceramic lenses offers an additional benefit of preventing cryogenic delamination of the coatings. We report on methodology of coating application and measurement of uniformity, repeatability, transmission property, and cryogenic adhesion performance.

  18. Understanding Pulsed Plasma Jets with Advanced Simulations, Ground and Space Experiments

    NASA Astrophysics Data System (ADS)

    Gatsonis, Nikolaos

    2004-11-01

    Pulsed plasma jets are found in diverse areas, such as thruster plume/spacecraft interactions, artificial release experiments, space plasma physics, and plasma materials processing. We review recent experimental and computational work and elucidate on physical characteristics and processes relevant to electric propulsion plumes. We present first results of experimental investigations of pulsed plasma thruster (PPT) plumes that led to the development of a new method of operation for triple and quadruple Langmuir probes. This novel current-mode method involves biasing all probe electrodes and requires the measurement of probe currents providing the electron temperature, the electron density and the ratio of ion speed to most probable thermal speed. We review the current-mode probe theory for a single species, two-temperature, collisionless plasma along with formal sensitivity analysis of the new diagnostic. The NASA Glenn Research Center laboratory Teflon® PPT used in the experiments was operating at discharge energies of 5, 20 and 40 Joules, with a pulse duration of 10-15 microseconds, ablating 20-50 micrograms/pulse. We present current-mode triple and quadruple probe measurements obtained at various locations in the plume of the plasma source. Extensive comparisons between double probe and current-mode probe measurements validate the new method. We present next computational modeling of plumes from a NASA Glenn Research Center laboratory micro Pulsed Plasma Thruster. The axisymmetric, hybrid (fluid/particle) methodology that introduced several new modeling and algorithmic approaches. Neutrals are modeled with the Direct Simulation Monte Carlo (DSMC) method and ions with a Hybrid-Particle-in-Cell (hybrid-PIC) collisional method. Electrons are modeled as a massless fluid with a momentum equation. The Non-Time-Counter methodology is used for neutral-neutral, elastic ion-neutral, and charge exchange collisions. Ion-electron collisions are modeled with the use of a

  19. Nonlinear plasma experiments in geospace with gigawatts of RF power at HAARP

    SciTech Connect

    Sheerin, J. P.; Cohen, Morris B.

    2015-12-10

    The ionosphere is the ionized uppermost layer of our atmosphere (from 70 – 500 km altitude) where free electron densities yield peak critical frequencies in the HF (3 – 30 MHz) range. The ionosphere thus provides a quiescent plasma target, stable on timescales of minutes, for a whole host of active plasma experiments. High power RF experiments on ionospheric plasma conducted in the U.S. have been reported since 1970. The largest HF transmitter built to date is the HAARP phased-array HF transmitter near Gakona, Alaska which can deliver up to 3.6 Gigawatts (ERP) of CW RF power in the range of 2.8 – 10 MHz to the ionosphere with microsecond pointing, power modulation, and frequency agility. With an ionospheric background thermal energy in the range of only 0.1 eV, this amount of power gives access to the highest regimes of the nonlinearity (RF intensity to thermal pressure) ratio. HAARP’s unique features have enabled the conduct of a number of unique nonlinear plasma experiments in the interaction region of overdense ionospheric plasma including generation of artificial aurorae, artificial ionization layers, VLF wave-particle interactions in the magnetosphere, parametric instabilities, stimulated electromagnetic emissions (SEE), strong Langmuir turbulence (SLT) and suprathermal electron acceleration. Diagnostics include the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the SuperDARN-Kodiak HF radar, spacecraft radio beacons, HF receivers to record stimulated electromagnetic emissions (SEE) and telescopes and cameras for optical emissions. We report on short timescale ponderomotive overshoot effects, artificial field-aligned irregularities (AFAI), the aspect angle dependence of the intensity of the HF-enhanced plasma line, and production of suprathermal electrons. One of the primary missions of HAARP, has been the generation of ELF (300 – 3000 Hz) and VLF (3 – 30 kHz) radio waves which are guided to global distances in the Earth

  20. Nonlinear plasma experiments in geospace with gigawatts of RF power at HAARP

    NASA Astrophysics Data System (ADS)

    Sheerin, J. P.; Cohen, Morris B.

    2015-12-01

    The ionosphere is the ionized uppermost layer of our atmosphere (from 70 - 500 km altitude) where free electron densities yield peak critical frequencies in the HF (3 - 30 MHz) range. The ionosphere thus provides a quiescent plasma target, stable on timescales of minutes, for a whole host of active plasma experiments. High power RF experiments on ionospheric plasma conducted in the U.S. have been reported since 1970. The largest HF transmitter built to date is the HAARP phased-array HF transmitter near Gakona, Alaska which can deliver up to 3.6 Gigawatts (ERP) of CW RF power in the range of 2.8 - 10 MHz to the ionosphere with microsecond pointing, power modulation, and frequency agility. With an ionospheric background thermal energy in the range of only 0.1 eV, this amount of power gives access to the highest regimes of the nonlinearity (RF intensity to thermal pressure) ratio. HAARP's unique features have enabled the conduct of a number of unique nonlinear plasma experiments in the interaction region of overdense ionospheric plasma including generation of artificial aurorae, artificial ionization layers, VLF wave-particle interactions in the magnetosphere, parametric instabilities, stimulated electromagnetic emissions (SEE), strong Langmuir turbulence (SLT) and suprathermal electron acceleration. Diagnostics include the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the SuperDARN-Kodiak HF radar, spacecraft radio beacons, HF receivers to record stimulated electromagnetic emissions (SEE) and telescopes and cameras for optical emissions. We report on short timescale ponderomotive overshoot effects, artificial field-aligned irregularities (AFAI), the aspect angle dependence of the intensity of the HF-enhanced plasma line, and production of suprathermal electrons. One of the primary missions of HAARP, has been the generation of ELF (300 - 3000 Hz) and VLF (3 - 30 kHz) radio waves which are guided to global distances in the Earth-ionosphere waveguide. We review

  1. Megagauss field generation for high-energy-density plasma science experiments.

    SciTech Connect

    Rovang, Dean Curtis; Struve, Kenneth William; Porter, John Larry Jr.

    2008-10-01

    There is a need to generate magnetic fields both above and below 1 megagauss (100 T) with compact generators for laser-plasma experiments in the Beamlet and Petawatt test chambers for focused research on fundamental properties of high energy density magnetic plasmas. Some of the important topics that could be addressed with such a capability are magnetic field diffusion, particle confinement, plasma instabilities, spectroscopic diagnostic development, material properties, flux compression, and alternate confinement schemes, all of which could directly support experiments on Z. This report summarizes a two-month study to develop preliminary designs of magnetic field generators for three design regimes. These are, (1) a design for a relatively low-field (10 to 50 T), compact generator for modest volumes (1 to 10 cm3), (2) a high-field (50 to 200 T) design for smaller volumes (10 to 100 mm3), and (3) an extreme field (greater than 600 T) design that uses flux compression. These designs rely on existing Sandia pulsed-power expertise and equipment, and address issues of magnetic field scaling with capacitor bank design and field inductance, vacuum interface, and trade-offs between inductance and coil designs.

  2. First results from a soft-x-ray laser experiment in a confined plasma column

    SciTech Connect

    Suckewer, S; Johnson, L C; Sato, K; Semet, A; Skinner, C H; Voorhees, D

    1982-04-01

    We present a description of the experimental set up and the first results from an experiment designed to achieve lasing action in the soft x-ray region of the spectrum. A 0.5 kJ CO/sub 2/ laser was focused into a target gas, typically CO/sub 2/, and the resulting plasma was confined in a 50 to 90 kG magnetic field. Spectroscopic diagnostics were used to monitor the n = 7 and n = 8 level populations of CVI as well as ultraviolet emission lines of CV and CIII, for different plasma conditions. We present data showing that as the confining magnetic field was increased, the plasma column diameter decreased, the CVI 3434 line intensity (7 ..-->.. 6 transition) increased and its decay time decreased consistent with earlier computer modeling. We also discuss the effect of the low intensity tail, normally present in CO/sub 2/ laser pulses, on the predicted population inversion. Analysis of the experimental data by computer simulation shows the range of expected total gain on the n = 3 to n = 2 transition at 182A in these experiments was G = 0.05 to 0.1 and the possibility for its significant increase.

  3. Laboratory astrophysical collisionless shock experiments with interpenetrating plasma flows on Omega and NIF

    NASA Astrophysics Data System (ADS)

    Ross, James; Park, H.-S.; Huntington, C.; Ryutov, D.; Drake, R. P.; Froula, D.; Gregori, G.; Levy, M.; Lamb, D.; Fiuza, F.; Petrasso, R.; Li, C.; Zylastra, A.; Rinderknecht, H.; Sakawa, Y.; Spitkovsky, A.

    2015-11-01

    Shock formation from high-Mach number plasma flows is observed in many astrophysical objects such as supernova remnants and gamma ray bursts. These are collisionless shocks as the ion-ion collision mean free path is much larger than the system size. It is believed that seed magnetic fields can be generated on a cosmologically fast timescale via the Weibel instability when such environments are initially unmagnetized. Here we present laboratory experiments using high-power lasers whose ultimate goal is to investigate the dynamics of collisionless shock formation in two interpenetrating plasma streams. Particle-in-cell numerical simulations have confirmed that the strength and structure of the generated magnetic field are consistent with the Weibel mediated electromagnetic nature and that the inferred magnetization level could be as high as ~ 1%. This paper will review recent experimental results from various laser facilities as well as the simulation results and the theoretical understanding of these observations. Taken together, these results imply that electromagnetic instabilities can be significant in both inertial fusion and astrophysical conditions. We will present results from initial NIF experiments, where we observe the neutrons and x-rays generated from the hot plasmas at the center of weakly collisional, counterstreaming flows. Prepared by LLNL under Contract DE-AC52-07NA27344.

  4. Results from colliding magnetized plasma jet experiments executed at the Trident laser facility

    NASA Astrophysics Data System (ADS)

    Manuel, M. J.-E.; Rasmus, A. M.; Kurnaz, C. C.; Klein, S. R.; Davis, J. S.; Drake, R. P.; Montgomery, D. S.; Hsu, S. C.; Adams, C. S.; Pollock, B. B.

    2015-11-01

    The interaction of high-velocity plasma flows in a background magnetic field has applications in pulsed-power and fusion schemes, as well as astrophysical environments, such as accretion systems and stellar mass ejections into the magnetosphere. Experiments recently executed at the Trident Laser Facility at the Los Alamos National Laboratory investigated the effects of an expanding aluminum plasma flow into a uniform 4.5-Tesla magnetic field created using a solenoid designed and manufactured at the University of Michigan. Opposing-target experiments demonstrate interesting collisional behavior between the two magnetized flows. Preliminary interferometry and Faraday rotation measurements will be presented and discussed. This work is funded by the U.S Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-NA0001840. Support for this work was provided by NASA through Einstein Postdoctoral Fellowship grant number PF3-140111 awarded by the Chandra X-ray Center, which is operated by the Astrophysical Observatory for NASA under contract NAS8-03060.

  5. LDEF Space Plasma-High Voltage Drainage Experiment post-flight results

    NASA Technical Reports Server (NTRS)

    Yaung, J. Y.; Blakkolb, B. K.; Wong, W. C.; Ryan, L. E.; Schurig, H. J.; Taylor, W. W. L.

    1993-01-01

    The Space Plasma-High Voltage Drainage Experiment (SP-HVDE) was comprised of two identical experimental trays. With one tray located on the leading (ram facing, B10) edge and the other located on the trailing (wake facing, D4) edge of the Long Duration Exposure Facility (LDEF), it was possible to directly compare the effects of ram and wake spacecraft environments on charged dielectric materials. Six arrays of Kapton dielectric samples of 2 mil, 3 mil, and 5 mil thicknesses maintained at +/- 300, +/- 500, and +/- 1000 voltage bias formed the experimental matrix of each tray. In addition, each tray carried two solar cell strings, one biased at +300 volts and the other at -300 volts, to study current leakage from High Voltage Solar Arrays (HVSA). The SP-HVDE provides the first direct, long-term, in-flight measurements of average leakage current through dielectric materials under electric stress. The experiment also yields information on the long term stability of the bulk dielectric properties of such materials. Data and findings of the SP-HVDE are an extension of those from shorter term flight experiments such as the PIX-1 (Plasma Interaction Experiment) and PIX-2 and are therefore valuable in the design and evaluation of long-lived space systems with high voltage systems exposed to the low earth orbital environment. A summary of the SP-HVDE post flight analysis final report delivered to the LDEF Project Office under contract to the National Aeronautics and Space Administration is presented.

  6. Experiments on Turbulence and Transport in the Edge Plasma of the Text Tokamak

    NASA Astrophysics Data System (ADS)

    Rhodes, Terry Lee

    We studied the turbulence and fluctuation driven transport in the edge plasma of the TEXT tokamak using a Langmuir probe array. In this dissertation we present three separate experiments, each of which examines a particular aspect of the edge turbulence and transport. In the first experiment we compare the observed fluctuation levels to the scaling predictions of several turbulence theories. We found that the fluctuations and transport were not proportional to the density and temperature gradients. Thus, drift wave turbulence theories, which predict strong scalings with density gradients, do not describe the edge plasma turbulence. In the second experiment we identify low frequency modulations (<=q1KHz) in the edge density, potential and temperature to be associated with heat and density pulses (sawtooth oscillations) which originate from the central region of the tokamak. Concurrent with the edge sawtooth oscillations are significant increases in the density and potential fluctuation levels. As a result of these increases, the fluctuation driven particle flux and associated heat flux are increased as much as 60 and 100% respectively during the sawtooth. This result has direct implications on the current methods of determining the electron thermal diffusivity chi_ {e}. The effect of electron cyclotron heating (ECH) on the edge plasma was investigated in the third experiment. Increases in edge temperature, density and potential with simultaneous increases in the density and potential fluctuations were observed during ECH. These increased fluctuation levels resulted in a significant increase (20-50%) in the fluctuation driven particle flux. Comparison of these results to an equal input power, ohmic only discharge showed similar increases in the average density, temperature and potential. However, the density fluctuations did not increase as much with the additional ohmic heating (compared to ECH) resulting in a generally smaller comparative level of fluctuation

  7. Integration and Test Flight Validation Plans for the Pulsed Plasma Thruster Experiment on EO- 1

    NASA Technical Reports Server (NTRS)

    Zakrzwski, Charles; Benson, Scott; Sanneman, Paul; Hoskins, Andy; Bauer, Frank H. (Technical Monitor)

    2002-01-01

    The Pulsed Plasma Thruster (PPT) Experiment on the Earth Observing One (EO-1) spacecraft has been designed to demonstrate the capability of a new generation PPT to perform spacecraft attitude control. The PPT is a small, self-contained pulsed electromagnetic propulsion system capable of delivering high specific impulse (900-1200 s), very small impulse bits (10-1000 uN-s) at low average power (less than 1 to 100 W). Teflon fuel is ablated and slightly ionized by means of a capacitative discharge. The discharge also generates electromagnetic fields that accelerate the plasma by means of the Lorentz Force. EO-1 has a single PPT that can produce thrust in either the positive or negative pitch direction. The flight validation has been designed to demonstrate of the ability of the PPT to provide precision pointing accuracy, response and stability, and confirmation of benign plume and EMI effects. This paper will document the success of the flight validation.

  8. Report Initial Work on Developing Plasma Modeling Capability in WARP for NDCX Experiments

    SciTech Connect

    Friedman, A; Cohen, R H; Grote, D P; Vay, J

    2007-12-14

    This milestone has been accomplished. The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) has developed and implemented an initial beam-in-plasma implicit modeling capability in Warp; has carried out tests validating the behavior of the models employed; has compared the results of electrostatic and electromagnetic models when applied to beam expansion in an NDCX-I relevant regime; has compared Warp and LSP results on a problem relevant to NDCX-I; has modeled wave excitation by a rigid beam propagating through plasma; and has implemented and begun testing a more advanced implicit method that correctly captures electron drift motion even when timesteps too large to resolve the electron gyro-period are employed. The HIFS-VNL is well on its way toward having a state-of-the-art source-to-target simulation capability that will enable more effective support of ongoing experiments in the NDCX series and allow more confident planning for future ones.

  9. Development of a Time-resolved Soft X-ray Spectrometer for Laser Produced Plasma Experiments

    SciTech Connect

    Cone, K V; Dunn, J; Schneider, M B; Baldis, H A; Brown, G V; Emig, J; James, D L; May, M J; Park, J; Shepherd, R; Widmann, K

    2010-05-12

    A 2400 line/mm variable spaced grating spectrometer (VSG) has been used to measure soft x-ray emission (8-22 {angstrom}) from laser-produced plasma experiments at Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) Laser Facility. The spectrometer was coupled to a Kentech x-ray streak camera to study the temporal evolution of soft x-rays emitted from the back of mylar and copper foils irradiated at 10{sup 15} W/cm{sup 2}. The instrument demonstrated a resolving power of {approx} 120 at 19 {angstrom} with a time resolution of 31 ps. The time-resolved copper emission spectrum was consistent with a photodiode monitoring the laser temporal pulse shape and indicated that the soft x-ray emission follows the laser heating of the target. The time and spectral resolution of this diagnostic make it useful for studies of high temperature plasmas.

  10. A 7 T Pulsed Magnetic Field Generator for Magnetized Laser Plasma Experiments

    NASA Astrophysics Data System (ADS)

    Hu, Guangyue; Liang, Yihan; Song, Falun; Yuan, Peng; Wang, Yulin; Zhao, Bin; Zheng, Jian

    2015-02-01

    A pulsed magnetic field generator was developed to study the effect of a magnetic field on the evolution of a laser-generated plasma. A 40 kV pulsed power system delivered a fast (~230 ns), 55 kA current pulse into a single-turn coil surrounding the laser target, using a capacitor bank of 200 nF, a laser-triggered switch and a low-impedance strip transmission line. A one-dimensional uniform 7 T pulsed magnetic field was created using a Helmholtz coil pair with a 6 mm diameter. The pulsed magnetic field was controlled to take effect synchronously with a nanosecond heating laser beam, a femtosecond probing laser beam and an optical Intensified Charge Coupled Device (ICCD) detector. The preliminary experiments demonstrate bifurcation and focusing of plasma expansion in a transverse magnetic field.

  11. Cryogenic Considerations for Superconducting Magnet Design for the Material Plasma Exposure eXperiment

    SciTech Connect

    Duckworth, Robert C; Demko, Dr. Jonathan A; Lumsdaine, Arnold; Caughman, John B; Goulding, Richard Howell; McGinnis, William Dean; Bjorholm, Thomas P; Rapp, Juergen

    2015-01-01

    In order to determine long term performance of plasma facing components such as diverters and first walls for fusion devices, next generation plasma generators are needed. A Material Plasma Exposure eXperiment (MPEX) has been proposed to address this need through the generation of plasmas in front of the target with electron temperatures of 1-15 eV and electron densities of 1020 to 1021 m-3. Heat fluxes on target diverters could reach 20 MW/m2. In order generate this plasma, a unique radio frequency helicon source and heating of electrons and ions through Electron Bernstein Wave (EBW) and Ion Cyclotron Resonance Heating (ICRH) has been proposed. MPEX requires a series of magnets with non-uniform central fields up to 2 T over a 5m length in the heating and transport region and 1 T uniform central field over a 1-m length on a diameter of 1.3 m. Given the field requirements, superconducting magnets are under consideration for MPEX. In order to determine the best construction method for the magnets, the cryogenic refrigeration has been analyzed with respect to cooldown and operational performance criteria for open-cycle and closed-cycle systems, capital and operating costs of these system, and maturity of supporting technology such as cryocoolers. These systems will be compared within the context of commercially available magnet constructions to determine the most economical method for MPEX operation. The current state of the MPEX magnet design including details on possible superconducting magnet configurations will be presented.

  12. Cryogenic considerations for superconducting magnet design for the material plasma exposure experiment

    NASA Astrophysics Data System (ADS)

    Duckworth, R. C.; Demko, J. A.; Lumsdaine, A.; Rapp, J.; Bjorholm, T.; Goulding, R. H.; Caughman, J. B. O.; McGinnis, W. D.

    2015-12-01

    In order to determine long term performance of plasma facing components such as diverters and first walls for fusion devices, next generation plasma generators are needed. A Material Plasma Exposure eXperiment (MPEX) has been proposed to address this need through the generation of plasmas in front of the target with electron temperatures of 1-15 eV and electron densities of 1020 to 1021 m-3. Heat fluxes on target diverters could reach 20 MW/m2. To generate this plasma, a unique radio frequency helicon source and heating of electrons and ions through Electron Bernstein Wave (EBW) and Ion Cyclotron Resonance Heating (ICRH) has been proposed. MPEX requires a series of magnets with non-uniform central fields up to 2 T over a 5-m length in the heating and transport region and 1 T uniform central field over a 1-m length on a diameter of 1.3 m. Given the field requirements, superconducting magnets are under consideration for MPEX. In order to determine the best construction method for the magnets, the cryogenic refrigeration has been analyzed with respect to cooldown and operational performance criteria for open-cycle and closed-cycle systems, capital and operating costs of these system, and maturity of supporting technology such as cryocoolers. These systems will be compared within the context of commercially available magnet constructions to determine the most economical method for MPEX operation. The current state of the MPEX magnet design including details on possible superconducting magnet configurations is presented.

  13. Autopsy as a tool for learning gross anatomy during 1st year MBBS

    PubMed Central

    Goyal, Parmod Kumar; Gupta, Monika; Kaur, Jaswinder

    2016-01-01

    Introduction: Embalmed cadavers are the primary tool for teaching anatomy. However, difficulties are encountered due to changed color/texture of organs, hardening of tissues, and smell of formaldehyde. To overcome these difficulties, dissections on a fresh human body were shown to the 1st year MBBS students, and their perception was noted. Materials and Methods: After taking universal precautionary measures, postmortem dissections were shown to students on voluntary donated bodies in the dissection hall, in addition to the traditional teaching on embalmed cadavers. Feedback was taken from students and faculty regarding the utility of these sessions. Results: Better appreciation of texture, orientation, location, and relations of organs in fresh body, integration of teaching, awareness of the process and laws related to body donations were the outcomes of the study. However, the smell and sight of blood was felt to be nauseating by some students, and some students were worried about the spread of infectious diseases. Conclusions: Visualizing single fresh body dissection during 1st year professional MBBS is recommended either on medicolegal autopsy or on voluntarily-donated bodies. PMID:27563594

  14. Laboratory experiments investigating magnetic field production via the Weibel instability in interpenetrating plasma flows

    NASA Astrophysics Data System (ADS)

    Huntington, Channing; Fiuza, Frederico; Ross, James Steven; Zylstra, Alex; Pollock, Brad; Drake, R. Paul; Froula, Dustin; Gregori, Gianluca; Kugland, Nathan; Kuranz, Carolyn; Levy, Matthew; Li, Chikang; Meinecke, Jena; Petrasso, Richard; Remington, Bruce; Ryutov, Dmitri; Sakawa, Youichi; Spitkovsky, Anatoly; Takabe, Hideke; Turnbull, David; Park, Hye-Sook

    2015-08-01

    Astrophysical collisionless shocks are often associated with the presence of strong magnetic fields in a plasma flow. The magnetic fields required for shock formation may either be initially present, for example in supernova remnants or young galaxies, or they may be self-generated in systems such as gamma-ray bursts (GRBs). In the case of GRB outflows, the intense magnetic fields are greater than those seeded by the GRB progenitor or produced by misaligned density and temperature gradients in the plasma flow (the Biermann-battery effect). The Weibel instability is one candidate mechanism for the generation of sufficiently strong fields to create a collisionless shock. Despite their crucial role in astrophysical systems, observation of the magnetic fields produced by Weibel instabilities in experiments has been challenging. Using a proton probe to directly image electromagnetic fields, we present evidence of Weibel-generated magnetic fields that grow in opposing, initially unmagnetized plasma flows from laser-driven laboratory experiments. Three-dimensional particle-in-cell simulations reveal that the instability efficiently extracts energy from the plasma flows, and that the self-generated magnetic energy reaches a few percent of the total energy in the system. This result demonstrates an experimental platform suitable for the investigation of a wide range of astrophysical phenomena, including collisionless shock formation in supernova remnants, large-scale magnetic field amplification, and the radiation signature from gamma-ray bursts.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  15. Dense Plasma Focus Z-Pinch Fully Kinetic Modeling and Ion Probe-Beam Experiments

    NASA Astrophysics Data System (ADS)

    Schmidt, Andrea

    2013-10-01

    The Z-pinch phase of a dense plasma focus (DPF) emits multiple-MeV ions on a cm-scale length, even for kJ-scale devices. The mechanisms through which these physically simple devices generate such high energy beams in a relatively short distance are not fully understood. We are exploring the mechanisms behind these large gradients using the first fully kinetic simulations of a DPF Z-pinch as well as an ion probe beam experiment in which a 4 MeV deuteron beam is injected along the z-axis of a DPF Z-pinch plasma and accelerated. Our table-top DPF has demonstrated >50 MV/m acceleration gradients during 800 J operation using a fast capacitive driver. We have now directly measured the DPF gradients and demonstrated acceleration of an injected ion beam for the first time. Our particle-in-cell simulations have successfully predicted observed DPF ion beams and neutron yield, which past fluid simulations have not reproduced. We have now experimentally measured and observed in the simulations for the first time, electric field oscillations near the lower hybrid frequency. This is suggestive that the lower hybrid drift instability, long speculated to be the cause of the anomalous plasma resistivity that produces large DPF gradients, is playing an important role. Direct comparisons between the experiment and simulations enhance our understanding of these plasmas and provide predictive design capability for accelerator and neutron source applications. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the Laboratory Directed Research and Development Program (11-ERD-063) at LLNL.

  16. A review of the findings of the plasma diagnostic package and associated laboratory experiments: Implications of large body/plasma interactions for future space technology

    NASA Technical Reports Server (NTRS)

    Murphy, Gerald B.; Lonngren, Karl E.

    1986-01-01

    The discoveries and experiments of the Plasma Diagnostic Package (PDP) on the OSS 1 and Spacelab 2 missions are reviewed, these results are compared with those of other space and laboratory experiments, and the implications for the understanding of large body interactions in a low Earth orbit (LEO) plasma environment are discussed. First a brief review of the PDP investigation, its instrumentation and experiments is presented. Next a summary of PDP results along with a comparison of those results with similar space or laboratory experiments is given. Last of all the implications of these results in terms of understanding fundamental physical processes that take place with large bodies in LEO is discussed and experiments to deal with these vital questions are suggested.

  17. Experiments and Simulations on Magnetically Driven Implosions in High Repetition Rate Dense Plasma Focus

    NASA Astrophysics Data System (ADS)

    Caballero Bendixsen, Luis; Bott-Suzuki, Simon; Cordaro, Samuel; Krishnan, Mahadevan; Chapman, Stephen; Coleman, Phil; Chittenden, Jeremy

    2015-11-01

    Results will be shown on coordinated experiments and MHD simulations on magnetically driven implosions, with an emphasis on current diffusion and heat transport. Experiments are run at a Mather-type dense plasma focus (DPF-3, Vc: 20 kV, Ip: 480 kA, E: 5.8 kJ). Typical experiments are run at 300 kA and 0.33 Hz repetition rate with different gas loads (Ar, Ne, and He) at pressures of ~ 1-3 Torr, usually gathering 1000 shots per day. Simulations are run at a 96-core HP blade server cluster using 3GHz processors with 4GB RAM per node.Preliminary results show axial and radial phase plasma sheath velocity of ~ 1x105 m/s. These are in agreement with the snow-plough model of DPFs. Peak magnetic field of ~ 1 Tesla in the radial compression phase are measured. Electron densities on the order of 1018 cm-3 anticipated. Comparison between 2D and 3D models with empirical results show a good agreement in the axial and radial phase.

  18. Investigation of iron opacity experiment plasma gradients with synthetic data analyses

    SciTech Connect

    Nagayama, T.; Bailey, J. E.; Rochau, G. A.; Hansen, S. B.; Mancini, R. C.; MacFarlane, J. J.; Golovkin, I.

    2012-10-15

    Experiments have been performed at Sandia National Laboratories Z-facility to validate iron opacity models relevant to the solar convection/radiation zone boundary. Sample conditions were measured by mixing Mg with the Fe and using Mg K-shell line transmission spectra, assuming that the plasma was uniform. We develop a spectral model that accounts for hypothetical gradients, and compute synthetic spectra to quantitatively evaluate the plasma gradient size that can be diagnosed. Two sample designs are investigated, assuming linear temperature and density gradients. First, Mg uniformly mixed with Fe enables temperature gradients greater than 10% to be detected. The second design uses Mg mixed into one side and Al mixed into the other side of the sample in an attempt to more accurately infer the sample gradient. Both temperature and density gradients as small as a few percent can be detected with this design. Experiments have successfully recorded spectra with the second design. In future research, the spectral model will be used to place bounds on gradients that exist in Z opacity experiments.

  19. Design and construction of Keda Space Plasma Experiment (KSPEX) for the investigation of the boundary layer processes of ionospheric depletions

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Zhang, Zhongkai; Lei, Jiuhou; Cao, Jinxiang; Yu, Pengcheng; Zhang, Xiao; Xu, Liang; Zhao, Yaodong

    2016-09-01

    In this work, the design and construction of the Keda Space Plasma EXperiment (KSPEX), which aims to study the boundary layer processes of ionospheric depletions, are described in detail. The device is composed of three stainless-steel sections: two source chambers at both ends and an experimental chamber in the center. KSPEX is a steady state experimental device, in which hot filament arrays are used to produce plasmas in the two sources. A Macor-mesh design is adopted to adjust the plasma density and potential difference between the two plasmas, which creates a boundary layer with a controllable electron density gradient and inhomogeneous radial electric field. In addition, attachment chemicals can be released into the plasmas through a tailor-made needle valve which leads to the generation of negative ions plasmas. Ionospheric depletions can be modeled and simulated using KSPEX, and many micro-physical processes of the formation and evolution of an ionospheric depletion can be experimentally studied.

  20. Development of effective power supply using electric double layer capacitor for static magnetic field coils in fusion plasma experiments.

    PubMed

    Inomoto, M; Abe, K; Yamada, T; Kuwahata, A; Kamio, S; Cao, Q H; Sakumura, M; Suzuki, N; Watanabe, T; Ono, Y

    2011-02-01

    A cost-effective power supply for static magnetic field coils used in fusion plasma experiments has been developed by application of an electric double layer capacitor (EDLC). A prototype EDLC power supply system was constructed in the form of a series LCR circuit. Coil current of 100 A with flat-top longer than 1 s was successfully supplied to an equilibrium field coil of a fusion plasma experimental apparatus by a single EDLC module with capacitance of 30 F. The present EDLC power supply has revealed sufficient performance for plasma confinement experiments whose discharge duration times are an order of several seconds. PMID:21361590

  1. Plasmas, Dielectrics and the Ultrafast: First Science and Operational Experience at FACET

    SciTech Connect

    Clarke, C.I.; Adli, E.; Corde, S.; Decker, F.J.; England, R.J.; Erickson, R.; Fisher, A.; Gessner, S.; Hast, C.; Hogan, M.J.; Li, S.Z.; Lipkowitz, N.; Litos, M.; Nosochkov, Y.; Seeman, J.; Sheppard, J.C.; Tudosa, I.; White, G.; Wienands, U.; Woodley, M.; Wu, Z.; /SLAC /UCLA

    2012-09-14

    FACET (Facility for Advanced Accelerator and Experimental Tests) is an accelerator R&D test facility that has been recently constructed at SLAC National Accelerator Laboratory. The facility provides 20 GeV, 3 nC electron beams, short (20 {micro}m) bunches and small (20 {micro}m wide) spot sizes, producing uniquely high power beams. FACET supports studies from many fields but in particular those of Plasma Wakefield Acceleration and Dielectric Wakefield Acceleration. FACET is also a source of THz radiation for material studies. We present the FACET design, initial operating experience and first science from the facility.

  2. Laser pulse propagation in a meter scale rubidium vapor/plasma cell in AWAKE experiment

    NASA Astrophysics Data System (ADS)

    Joulaei, A.; Moody, J.; Berti, N.; Kasparian, J.; Mirzanejhad, S.; Muggli, P.

    2016-09-01

    We present the results of numerical studies of laser pulse propagating in a 3.5 cm Rb vapor cell in the linear dispersion regime by using a 1D model and a 2D code that has been modified for our special case. The 2D simulation finally aimed at finding laser beam parameters suitable to make the Rb vapor fully ionized to obtain a uniform, 10 m-long, at least 1 mm in radius plasma in the next step for the AWAKE experiment.

  3. Numerical simulations of a nonequilibrium argon plasma in a shock-tube experiment

    NASA Technical Reports Server (NTRS)

    Cambier, Jean-Luc

    1991-01-01

    A code developed for the numerical modeling of nonequilibrium radiative plasmas is applied to the simulation of the propagation of strong ionizing shock waves in argon gas. The simulations attempt to reproduce a series of shock-tube experiments which will be used to validate the numerical models and procedures. The ability to perform unsteady simulations makes it possible to observe some fluctuations in the shock propagation, coupled to the kinetic processes. A coupling mechanism by pressure waves, reminiscent of oscillation mechanisms observed in detonation waves, is described. The effect of upper atomic levels is also briefly discussed.

  4. An Alternative Analysis of Some Recent Diffusion Experiments on the Large Plasma Device

    SciTech Connect

    Simon, A.

    2008-04-07

    The results of a recent numerical analysis of a diffusion experiment on the large plasma device (LAPD) are re-examined. A simplified analytic solution of the transport equations is obtained by including previously omitted contributions to the transport. This solution strongly suggests that an accurate determination of the perpendicular diffusion coefficient would be very difficult in the specific LAPD experimental arrangement, due to near-cancellation of large terms. Thus, caution should be exercised in claiming that Bohm diffusion, or its suppression in the presence of a large applied radial voltage, has been observed.

  5. Experiments with Plasmas Produced by Potassium-Seeded Cyanogen Oxygen Flames for Study of Radio Transmission at Simulated Reentry Vehicle Plasma Conditions

    NASA Technical Reports Server (NTRS)

    Huber, Paul W.; Gooderum, Paul B.

    1961-01-01

    A method for the chemical production of an ionized gas stream for application to radio transmission studies is described. Involved is the combustion of gaseous cyanogen and oxygen with the addition of vaporized potassium in some cases to further increase the ionization. Experiments are described in which a 3-inch-diameter subsonic free jet at atmospheric pressure is used, and the results are presented. The plasma obtained by using this method is sufficient to simulate plasma conditions expected for reentering hypersonic vehicles. The unseeded plasma stream temperature is indicated to be about 4,200 K, with the degree of ionization indicated to be that expected from thermal equilibrium considerations. Measurements of radio-signal loss due to the unseeded flame plasma are presented for microwaves of 8 to 20 kmc transmitted through the stream and for a dipole transmitting model of 219.5 mc immersed in the stream. Favorable comparison of these results with the simple plane-wave signal-attenuation theory was obtained. In the case of a 9.4-kmc microwave signal of 30-kw peak power, the preliminary indication is that the plasma characteristics were not changed due to this strong signal. Comparison of a simplified concept of radio-signal attenuation due to plasmas is made with some hypersonic reentry vehicle signal-loss data. Other areas of plasma research using this method for the transmission problem are indicated.

  6. Three-dimensional MHD simulation of the Caltech plasma jet experiment: first results

    SciTech Connect

    Zhai, Xiang; Bellan, Paul M.; Li, Hui; Li, Shengtai E-mail: pbellan@caltech.edu E-mail: sli@lanl.gov

    2014-08-10

    Magnetic fields are believed to play an essential role in astrophysical jets with observations suggesting the presence of helical magnetic fields. Here, we present three-dimensional (3D) ideal MHD simulations of the Caltech plasma jet experiment using a magnetic tower scenario as the baseline model. Magnetic fields consist of an initially localized dipole-like poloidal component and a toroidal component that is continuously being injected into the domain. This flux injection mimics the poloidal currents driven by the anode-cathode voltage drop in the experiment. The injected toroidal field stretches the poloidal fields to large distances, while forming a collimated jet along with several other key features. Detailed comparisons between 3D MHD simulations and experimental measurements provide a comprehensive description of the interplay among magnetic force, pressure, and flow effects. In particular, we delineate both the jet structure and the transition process that converts the injected magnetic energy to other forms. With suitably chosen parameters that are derived from experiments, the jet in the simulation agrees quantitatively with the experimental jet in terms of magnetic/kinetic/inertial energy, total poloidal current, voltage, jet radius, and jet propagation velocity. Specifically, the jet velocity in the simulation is proportional to the poloidal current divided by the square root of the jet density, in agreement with both the experiment and analytical theory. This work provides a new and quantitative method for relating experiments, numerical simulations, and astrophysical observation, and demonstrates the possibility of using terrestrial laboratory experiments to study astrophysical jets.

  7. Spectroscopic measurements of temperature and plasma impurity concentration during magnetic reconnection at the Swarthmore Spheromak Experiment

    SciTech Connect

    Chaplin, V. H.; Brown, M. R.; Cohen, D. H.; Gray, T.; Cothran, C. D.

    2009-04-15

    Electron temperature measurements during counterhelicity spheromak merging studies at the Swarthmore Spheromak Experiment (SSX) [M. R. Brown, Phys. Plasmas 6, 1717 (1999)] are presented. VUV monochromator measurements of impurity emission lines are compared with model spectra produced by the non-LTE excitation kinematics code PRISMSPECT[J. J. MacFarlane et al., in Proceedings of the Third Conference on Inertial Fusion Science and Applications (2004)] to yield the electron temperature in the plasma with 1 {mu}s time resolution. Average T{sub e} is seen to increase from 12 to 19 eV during spheromak merging. Average C III ion temperature, measured with a new ion Doppler spectrometer (IDS) [C. D. Cothran et al., Rev. Sci. Instrum. 77, 063504 (2006)], likewise rises during spheromak merging, peaking at {approx}22 eV, but a similar increase in T{sub i} is seen during single spheromak discharges with no merging. The VUV emission line measurements are also used to constrain the concentrations of various impurities in the SSX plasma, which are dominated by carbon, but include some oxygen and nitrogen. A burst of soft x-ray emission is seen during reconnection with a new four-channel detector (SXR). There is evidence for spectral changes in the soft x-ray emission as reconnection progresses, although our single-temperature equilibrium spectral models are not able to provide adequate fits to all the SXR data.

  8. Spectroscopic measurements of temperature and plasma impurity concentration during magnetic reconnection at the Swarthmore Spheromak Experiment

    NASA Astrophysics Data System (ADS)

    Chaplin, V. H.; Brown, M. R.; Cohen, D. H.; Gray, T.; Cothran, C. D.

    2009-04-01

    Electron temperature measurements during counterhelicity spheromak merging studies at the Swarthmore Spheromak Experiment (SSX) [M. R. Brown, Phys. Plasmas 6, 1717 (1999)] are presented. VUV monochromator measurements of impurity emission lines are compared with model spectra produced by the non-LTE excitation kinematics code PRISMSPECT [J. J. MacFarlane et al., in Proceedings of the Third Conference on Inertial Fusion Science and Applications (2004)] to yield the electron temperature in the plasma with 1 μs time resolution. Average Te is seen to increase from 12 to 19 eV during spheromak merging. Average C III ion temperature, measured with a new ion Doppler spectrometer (IDS) [C. D. Cothran et al., Rev. Sci. Instrum. 77, 063504 (2006)], likewise rises during spheromak merging, peaking at ˜22 eV, but a similar increase in Ti is seen during single spheromak discharges with no merging. The VUV emission line measurements are also used to constrain the concentrations of various impurities in the SSX plasma, which are dominated by carbon, but include some oxygen and nitrogen. A burst of soft x-ray emission is seen during reconnection with a new four-channel detector (SXR). There is evidence for spectral changes in the soft x-ray emission as reconnection progresses, although our single-temperature equilibrium spectral models are not able to provide adequate fits to all the SXR data.

  9. Nonlinear Plasma Experiments in Geospace with Gigawatts of RF Power at HAARP

    NASA Astrophysics Data System (ADS)

    Sheerin, J. P.; Rayyan, N.; Watkins, B. J.; Bristow, W. A.; Bernhardt, P. A.

    2014-10-01

    The HAARP phased-array HF transmitter at Gakona, AK delivers up to 3.6 GW (ERP) of HF power in the range of 2.8 - 10 MHz to the ionosphere with millisecond pointing, power modulation, and frequency agility. HAARP's unique features have enabled the conduct of a number of nonlinear plasma experiments in the interaction region of overdense ionospheric plasma including stimulated electromagnetic emissions (SEE), artificial aurora, artificial ionization layers, VLF wave-particle interactions in the magnetosphere, strong Langmuir turbulence (SLT) and suprathermal electron acceleration. Diagnostics include the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the SuperDARN-Kodiak HF radar, spacecraft radio beacons, HF receivers to record stimulated electromagnetic emissions (SEE) and telescopes and cameras for optical emissions. We report on short timescale ponderomotive overshoot effects, artificial field-aligned irregularities (AFAI), the aspect angle dependence of the intensity of the plasma line, and suprathermal electrons. Applications are made to the study and control of irregularities affecting spacecraft communication and navigation systems.

  10. Overview of Final CDX-U Experiments with Lithium Plasma-Facing Components

    NASA Astrophysics Data System (ADS)

    Kaita, R.; Majeski, R.; Gray, T.; Kugel, H.; Mansfield, D.; Spaleta, J.; Timberlake, J.; Zakharov, L.; Doerner, R.; Lynch, T.; Maingi, R.; Soukhanovskii, V.

    2006-10-01

    The final phase of Current Drive eXperiment Upgrade (CDX-U) research involved plasma-facing surfaces nearly completely coated with lithium. The CDX-U device is a spherical tokamak with the following typical parameters: R=34 cm, a=22 cm, Bt=2 kG, Ip=100 kA, Te(0)=100 eV, and ne(0)=5x10^19 m-3. Electron beam-induced evaporation from a lithium target and vapor deposition from a lithium-filled oven created lithium coatings. Convective flows for highly-efficient power dissipation were observed in the lithium with electron beam heating. Lithium layers up to 100 nm thick between were deposited between discharges. These coatings reduced global recycling coefficients to as low as 0.3, a record for magnetically-confined hydrogen plasmas. New magnetic diagnostics constrained equilibrium reconstructions that were used to determine energy confinement times. With lithium coatings, plasmas had the largest global confinement enhancement ever achieved in an Ohmically-heated tokamak, exceeding ITER98P(y,1) scaling by up to a factor of three.

  11. Plasma isotopic change over experiments in JET under Carbon and ITER-Like Wall conditions

    NASA Astrophysics Data System (ADS)

    Loarer, T.; Brezinsek, S.; Philipps, V.; Romanelli-Gruenhagen, S.; Alves, D.; Carvalho, I.; Douai, D.; Esser, H. G.; Felton, R.; Frigione, D.; Kruezi, U.; Reux, C.; Smith, R.; Stamp, M. F.; Vartanian, S.

    2015-08-01

    Starting with a wall loaded by H2, change over experiments from H2 to D2 have been carried out in JET-ILW. A series of 13 repetitive pulses (cumulating 215 s in divertor configuration) have been performed under conditions of: Ip = 2.0 MA, BT = 2.4 T, = 4.5 × 1019 m-3 with a constant gas injection of 3.0 × 1021 D s-1 and 0.5 MW of auxiliary heating by ICRH in L-mode. Gas balance analysis shows that the total amount of H removed from the wall is in the range of 3 × 1022 D compared to 2 × 1023 D for JET-C. This is consistent with the faster decay of the H plasma concentration and the drop of the retention also by a similar factor when removing all the carbon components. Isotopic plasma wall changeover is also demonstrated to allow for removal of some D/T from the device. However, since plasma change over also contributes to long-term retention by codeposition, in ITER, change over in between each discharge might not be effective to reduce the fuel retention on the long-term.

  12. Analysis and experiments on thermal plasma processing for ultrafine powder synthesis of aluminium nitride

    SciTech Connect

    Ahn, H.; Hur, M.; Hong, S.H.

    1996-12-31

    Plasma synthesis experiments for producing ultrafine powders of aluminum nitride (AlN) are carried out using a non-transferred dc plasma torch of which jet flame can vaporize the aluminum powders injected into it to make the chemical reaction with nitrogen gas. For predicting the optimum processing parameters (the size, injected location and velocity of Al powders, and the ratio of nitrogen to argon arc gases), the trajectory and the evaporation state of an Al particle arc found by solving momentum and heat transfer equations. In addition, equilibrium chemical compositions are analyzed by the Gibbs free-energy minimization method to know the temperatures at which AlN synthesis occurs dominantly. A synthesis system consisting of a plasma torch, a reactor and a quenching chamber has been built for synthesis and quenching process of ultrafine powders of AlN. A fully-saturated fractional factorial test is employed to determine optimum process conditions for input power to the torch and flow rates of arc, carrier and reaction gases.

  13. Schlieren, Phase-Contrast, and Spectroscopy Diagnostics for the LBNL HIF Plasma Channel Experiment

    NASA Astrophysics Data System (ADS)

    Ponce, D. M.; Niemann, C.; Fessenden, T. J.; Leemans, W.; Vandersloot, K.; Dahlbacka, G.; Yu, S. S.; Sharp, W. M.; Tauschwitz, A.

    1999-11-01

    The LBNL Plasma Channel experiment has demonstrated stable 42-cm Z-pinch discharge plasma channels with peak currents in excess of 50 kA for a 7 torr nitrogen, 30 kV discharge. These channels offer the possibility of transporting heavy-ion beams for inertial fusion. We postulate that the stability of these channels resides in the existance of a neutral-gas density depresion created by a pre-pulse discharge before the main capacitor bank discharge is created. Here, we present the results and experimental diagnostics setup used for the study of the pre-pulse and main bank channels. Observation of both the plasma and neutral gas dynamics is achieved. Schlieren, Zernike's phase-contrast, and spectroscopic techniques are used. Preliminary Schlieren results show a gas shockwave moving radially at a rate of ≈ 10^6 mm/sec as a result of the fast and localized deposited energy during the evolution of the pre-pulse channel. This data will be used to validate simulation codes (BUCKY and CYCLOPS).

  14. Baseline geoenvironmental experiments for in-situ soil transformation by plasma torch

    SciTech Connect

    Beaver, J.R.; Mayne, P.W.

    1995-12-31

    The advent of the nontransferred plasma arc torch has implicated a range of in-situ geoenvironmental applications that can revolutionize methods of ground modification and field remediation of contaminated sites. With reverse polarity nontransferred arc type plasma torches, temperatures of 4,000 C to 7,000 C can be directed at specific targets of contaminated soil or waste. At these extreme temperatures, all organic materials within the soil undergo pyrolysis, while the bulk composition is transformed into a magma that subsequently cools to form a vitrified mass resembling volcanic obsidian or a dense partially crystalline material resembling microcrystalline igneous rock. Simulations of in-situ transformation of soil have been conducted using both 100-kW and 240-kW torches to alter clay, silty sand, and sand in chamber tests. Although these materials are primarily composed of silica and alumina oxides having melting temperatures of 1,100 C to 1,600 C, the formation of a spheroidal magma core occurred within the first five minutes of exposure to the plasma flame. Experiments were conducted to quantify the improved engineering properties that occur after transformation and to demonstrate the relative effects of power level, water content, and soil type on the size and strength of the altered material. The ongoing research also serves as a baseline study for further experimentation that will focus on the in-situ remediation of soils with varied contaminants.

  15. High density experiments in TCV ohmically heated and L-mode plasmas

    NASA Astrophysics Data System (ADS)

    Kirneva, N. A.; Behn, R.; Canal, G. P.; Coda, S.; Duval, B. P.; Goodman, T. P.; Labit, B.; Mustafin, N. A.; Karpushov, A. N.; Pochelon, A.; Porte, L.; Sauter, O.; Silva, M.; Tal, B.; Vuille, V.

    2015-02-01

    Recent experiments have been performed on the Tokamak à configuration variable (TCV) to investigate the confinement properties of high density plasmas and the mechanism behind the density limit. In a limiter configuration with plasma elongation κ =1.3-1.4 and triangularity δ =0.2- 0.3 the operational density range has been extended up to 0.65 of the Greenwald density at {{I}\\text{p}}=200  kA ({{q}95}=3.7 ) and even to the Greenwald value at low plasma current {{I}\\text{p}}=110  kA ({{q}95}=7 ). A transition from the linear to the saturated ohmic confinement regime is observed at high density ˜ 0.4{{n}\\text{GW}} . A further density increase leads to sawtooth stabilization and is accompanied by a decrease of the energy and particle confinement times. The development of the disruption at the density limit was preceded by sawtooth stabilization. It is shown that electron cyclotron heating leads to the prevention of sawtooth stabilization and then to the increase of the density limit value.

  16. PASP, a high voltage array/plasma interaction experiment. [Photovoltaic Array Space Power

    NASA Technical Reports Server (NTRS)

    Burger, Dale R.

    1991-01-01

    The author discusses the photovoltaic array space power (PASP) experiment, which is designed to obtain data on the interaction between high-voltage photovoltaic arrays and the polar, low-earth plasma environment. Up to six small test arrays (three each of planar and concentrator designs) can be voltage biased over a range of +/- 500 V. During the bias voltage sequence, the array current leakage is measured and array arc events are monitored. If any arcing occurs the arc characteristics will be measured by a transient pulse monitor. An emitter is included to allow voltage bias to be applied to a plasma-charged or uncharged spacecraft. Similarly, the frames of the concentrator arrays can be left floating or can be tied to the negative array terminal. An environmental data scan is made before each bias voltage sequence. This scan collects information on the plasma, array-current-versus-voltage curves, and neutral particle partial pressure. The requirement for high voltages created problems which were met by circuit isolation and logical fault protection.

  17. Results from D-T Experiments on TFTR and Implications for Achieving an Ignited Plasma

    SciTech Connect

    Hawryluk, R.J. and the TFTR Group

    1998-07-14

    Progress in the performance of tokamak devices has enabled not only the production of significant bursts of fusion energy from deuterium-tritium plasmas in the Tokamak Fusion Test Reactor (TFTR) and the Joint European Torus (JET) but, more importantly, the initial study of the physics of burning magnetically confined plasmas. As a result of the worldwide research on tokamaks, the scientific and technical issues for achieving an ignited plasma are better understood and the remaining questions more clearly defined. The principal research topics which have been studied on TFTR are transport, magnetohydrodynamic stability, and energetic particle confinement. The integration of separate solutions to problems in each of these research areas has also been of major interest. Although significant advances, such as the reduction of turbulent transport by means of internal transport barriers, identification of the theoretically predicted bootstrap current, and the study of the confinement of energetic fusion alpha-particles have been made, interesting and important scientific and technical issues remain for achieving a magnetic fusion energy reactor. In this paper, the implications of the TFTR experiments for overcoming these remaining issues will be discussed.

  18. Results from D-T experiments on TFTR and implications for achieving an ignited plasma

    SciTech Connect

    Hawryluk, R.J.; Blanchard, W.; Batha, S.

    1998-07-01

    Progress in the performance of tokamak devices has enable not only the production of significant bursts of fusion energy from deuterium-tritium plasmas in the Tokamak Fusion Test Reactor (TFTR) and the Joint European Torus (JET) but, more importantly, the initial study of the physics of burning magnetically confined plasmas. As a result of the worldwide research on tokamaks, the scientific and technical issues for achieving an ignited plasma are better understood and the remaining questions more clearly defined. The principal research topics which have been studied on TFTR are transport, magnetohydrodynamic stability, and energetic particle confinement. The integration of separate solutions to problems in each of these research areas has also been of major interest. Although significant advances, such as the reduction of turbulent transport by means of internal transport barriers, identification of the theoretically predicted bootstrap current, and the study of the confinement of energetic fusion alpha-particles have been made, interesting and important scientific and technical issues remain. In this paper, the implications for the TFTR experiments for overcoming these remaining issues will be discussed.

  19. Hall Reconnection in Partially Ionized Plasmas in the Magnetic Reconnection Experiment

    NASA Astrophysics Data System (ADS)

    Lawrence, Eric; Ji, Hantao; Yamada, Masaaki; Yoo, Jongsoo

    2011-10-01

    In many space and astrophysical plasmas, such as the solar chromosphere and protoplanetary disks, the degree of ionization can be quite low; often 1% or less. In addition, magnetic reconnection is thought to be a fundamental process in these plasmas. The presence of a large neutral atom population has at least two effects relevant to magnetic reconnection. First, electron-neutral collisions enhance resistive dissipation. Second, strong ion-neutral collisions increase effective ion inertia. This may increase the length scales on which fast Hall reconnection is predicted to occur. By using high gas fill pressures in the Magnetic Reconnection Experiment (MRX), we can study reconnection in partially or weakly ionized plasmas (nn /ne = 1 - - 200). A newly constructed magnetic probe array allows us to make magnetic measurements of the reconnection region with high spatial resolution and large spatial extent. This will allow us to diagnose, for example, the structure of the Hall quadrupole field in these conditions. Langmuir and spectroscopic diagnostics will also provide insight into how neutrals affect the reconnection process. These results will also be discussed in the context of ongoing theoretical work.

  20. Characterization of the plasma current quench during disruptions in the National Spherical Torus Experiment

    SciTech Connect

    Gerhardt, S.P., Menard, J.E., and the NSTX Research Team

    2008-12-17

    A detailed analysis of the plasma current quench in the National Spherical Torus Experiment [M.Ono, et al Nuclear Fusion 40, 557 (2000)] is presented. The fastest current quenches are fit better by a linear waveform than an exponential one. Area-normalized current quench times down to .4 msec/m2 have been observed, compared to the minimum of 1.7 msec/m2 recommendation based on conventional aspect ratio tokamaks; as noted in previous ITPA studies, the difference can be explained by the reduced self-inductance at low aspect ratio and high-elongation. The maximum instantaneous dIp/dt is often many times larger than the mean quench rate, and the plasma current before the disruption is often substantially less than the flat-top value. The poloidal field time-derivative during the disruption, which is directly responsible for driving eddy currents, has been recorded at various locations around the vessel. The Ip quench rate, plasma motion, and magnetic geometry all play important roles in determining the rate of poloidal field change.

  1. Laboratory experiments in the argon plasma perturbed by injections of the electronegative gases

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao; Cao, Jin-xiang; Liu, Yu; Yu, Peng-cheng; Zhang, Zhong-kai

    2016-07-01

    In this study, laboratory observations of the perturbations of the magnetic field are reported due to the injection of attachment chemicals (CF4, SF6, and CO2) into argon plasmas. Besides the well-known electron density reduction, we also observed magnetic field perturbation in the experiment. The measured induced voltage B ˙ , which is taken as a proxy of the time-changing electromagnetic field, fluctuates in the boundary layer between the ambient plasmas and negative ions plasmas. Perturbations of the magnetic field were investigated by changing the ambient pressure and ratio of attachment chemicals. The measured B ˙ keeps increasing in these lower pressures; but it no longer increases as the ambient pressure higher than a threshold, e.g., for CF4, SF6, and CO2, the transition pressure is 6Pa, 5Pa and 4Pa, respectively. The magnitude of the B ˙ increase with the change of the ratio of release flow until at higher ratios, e.g., 40%. We transformed these time-sampled data into the frequency domain and found coherent modes with fundamental frequencies lying in the lower hybrid range. In addition, these coherent frequencies show a frequency drift with the increase of the contents of the negative ions. These modes were suggested as the magnetic component of electron-ion hybrid mode. This work has an important application in the study of artificially-created ionospheric depletion which is usually generated by releasing of attachment chemicals in the upper atmosphere.

  2. ANALYSIS OF DATA FROM Z-PINCH MTF TARGET PLASMA EXPERIMENTS

    SciTech Connect

    F. WYSOCKI; J. TACCETTI; ET AL

    1999-04-01

    The Los Alamos National Laboratory Colt facility has been used to create target plasma for Magnetized Target Fusion (MTF). The primary results regarding magnetic field, plasma density, plasma temperature, and hot plasma lifetime are summarized and the suitability of these plasma targets for MTF is assessed.

  3. Effect of plasma shaping on performance in the National Spherical Torus Experiment

    SciTech Connect

    Gates, D. A.; Maingi, R.; Menard, J.; Kaye, S.; Sabbagh, S. A.; Taylor, G.; Wilson, J. R.; Bell, M. G.; Bell, R. E.; Bernabei, S.; Bialek, J.; Biewer, T.; Blanchard, W.; Boedo, J.; Bush, C.; Carter, M. D.; Choe, W.; Crocker, N.; Darrow, D. S.; Davis, W.; Delgado-Aparicio, L.; Diem, S.; Ferron, J.; Field, A.; Foley, J.; Fredrickson, E. D.; Harvey, R.; Hatcher, R. E.; Heidbrink, W.; Hill, K.; Hosea, J. C.; Jarboe, T. R.; Johnson, D. W.; Kaita, R.; Kessel, C.; Kubota, S.; Kugel, H. W.; Lawson, J.; LeBlanc, B. P.; Lee, K. C.; Levinton, F.; Manickam, J.; Maqueda, R.; Marsala, R.; Mastrovito, D.; Mau, T. K.; Medley, S. S.; Meyer, H.; Mikkelsen, D. R.; Mueller, D.; Munsat, T.; Nelson, B. A.; Neumeyer, C.; Nishino, N.; Ono, M.; Park, H.; Park, W.; Paul, S.; Peebles, W.; Peng, M.; Phillips, C.; Pigarov, A.; Pinsker, R.; Ram, A.; Ramakrishnan, S.; Raman, R.; Rasmussen, D.; Redi, M.; Rensink, M.; Rewoldt, G.; Robinson, J.; Roney, P.; Roquemore, L.; Ruskov, E.; Ryan, P.; Schneider, H.; Skinner, C. H.; Smith, D. R.; Sontag, A.; Soukhanovskii, V.; Stevenson, T.; Stotler, D.; Stratton, B.; Stutman, D.; Swain, D.; Synakowski, E.; Takase, Y.; Tritz, K.; Halle, A. von; Wade, M.; White, R.; Wilgen, J.; Williams, M.; Zhu, W.; Zweben, S. J.; Akers, R.; Beiersdorfer, P.; Betti, R.; Bigelow, T.

    2006-01-01

    The National Spherical Torus Experiment (NSTX) has explored the effects of shaping on plasma performance as determined by many diverse topics including the stability of global magnetohydrodynamic (MHD) modes (e.g., ideal external kinks and resistive wall modes), edge localized modes (ELMs), bootstrap current drive, divertor flux expansion, and heat transport. Improved shaping capability has been crucial to achieving βt ~ 40%. Precise plasma shape control has been achieved on NSTX using real-time equilibrium reconstruction. NSTX has simultaneously achieved elongation κ ~ 2.8 and triangularity delta ~ 0.8. Ideal MHD theory predicts increased stability at high values of shaping factor S equivalent to q95Ip/(aBt), which has been observed at large values of the S ~ 37[MA/(m • T)] on NSTX. The behavior of ELMs is observed to depend on plasma shape. A description of the ELM regimes attained as shape is varied will be presented. Increased shaping is predicted to increase the bootstrap fraction at fixed Ip. The achievement of strong shaping has enabled operation with 1 s pulses with Ip=1 MA, and for 1.6 s for Ip=700 kA. Analysis of the noninductive current fraction as well as empirical analysis of the achievable plasma pulse length as elongation is varied will be presented. Data are presented showing a reduction in peak divertor heat load due to increasing in flux expansion.

  4. Cognitive-based approach in teaching 1st year Physics for Life Sciences, including Atmospheric Physics and Climate Change components

    NASA Astrophysics Data System (ADS)

    Petelina, S. V.

    2009-12-01

    Most 1st year students who take the service course in Physics - Physics for Life Sciences - in Australia encounter numerous problems caused by such factors as no previous experience with this subject; general perception that Physics is hard and only very gifted people are able to understand it; lack of knowledge of elementary mathematics; difficulties encountered by lecturers in teaching university level Physics to a class of nearly 200 students with no prior experience, diverse and sometime disadvantageous backgrounds, different majoring areas, and different learning abilities. As a result, many students either drop, or fail the subject. In addition, many of those who pass develop a huge dislike towards Physics, consider the whole experience as time wasted, and spread this opinion among their peers and friends. The above issues were addressed by introducing numerous changes to the curriculum and modifying strategies and approaches in teaching Physics for Life Sciences. Instead of a conventional approach - teaching Physics from simple to complicated, topic after topic, the students were placed in the world of Physics in the same way as a newborn child is introduced to this world - everything is seen all the time and everywhere. That created a unique environment where a bigger picture and all details were always present and interrelated. Numerous concepts of classical and modern physics were discussed, compared, and interconnected all the time with “Light” being a key component. Our primary field of research is Atmospheric Physics, in particular studying the atmospheric composition and structure using various satellite and ground-based data. With this expertise and also inspired by an increasing importance of training a scientifically educated generation who understands the challenges of the modern society and responsibilities that come with wealth, a new section on environmental physics has been developed. It included atmospheric processes and the greenhouse

  5. EDITORIAL: The 1st International Conference on Nanomanufacturing (NanoMan2008) The 1st International Conference on Nanomanufacturing (NanoMan2008)

    NASA Astrophysics Data System (ADS)

    Luo, Jack Jiqui; Fang, Fengzhou

    2009-05-01

    Nanomanufacturing is an emerging technology in the field of synthesis of nanomaterials, manufacture of nanodevices, nanosystems and the relevant characterization technologies, and will greatly impact our society and environment: speeding up scientific discovery, technological development, improving healthcare and living standards and slowing down the exhaustion of energy resources, to name but few. The 1st International Conference on Nanomanufacturing (NanoMan2008) was held on the 13-16 July 2008 in Singapore in conjunction with ThinFilm2008 (The 4th International Conference on Technological Advances of Thin Films & Surface Coatings). Approximately 140 delegates from all over the world have participated in the conference and presented their latest discoveries and technological developments. The main focuses of the conference were modern nanomanufacturing by laser machining, focused ion beam fabrication, nano/micro-molding/imprinting, nanomaterial synthesis and characterization, nanometrology and nano/microsystems fabrication and characterization. There was also great interest in applications of nanomanufacturing technologies in traditional areas such as free form machining, polishing and grinding with nano-scale precision and the smoothness of surfaces of objects, and applications in space exploration, military and medicine. This special issue is devoted to NanoMan2008 with a collection of 9 invited talks presented at the conference, covering all the topics of nanomanufacturing technology and development. These papers have been upgraded by the authors with new results and discoveries since the preparation of the conference manuscripts, hence presenting the latest developments. We would like to take this opportunity to thank all the delegates who attended the conference and made the conference successful, and to the authors who contributed papers to this special issue. Thanks also go to the conference committee for their efforts and devotion to the conference. We

  6. Perceptual narrowing of linguistic sign occurs in the 1st year of life.

    PubMed

    Palmer, Stephanie Baker; Fais, Laurel; Golinkoff, Roberta Michnick; Werker, Janet F

    2012-01-01

    Over their 1st year of life, infants'"universal" perception of the sounds of language narrows to encompass only those contrasts made in their native language (J. F. Werker & R. C. Tees, 1984). This research tested 40 infants in an eyetracking paradigm and showed that this pattern also holds for infants exposed to seen language-American Sign Language (ASL). Four-month-old, English-only, hearing infants discriminated an ASL handshape distinction, while 14-month-old hearing infants did not. Fourteen-month-old ASL-learning infants, however, did discriminate the handshape distinction, suggesting that, as in heard language, exposure to seen language is required for maintenance of visual language discrimination. Perceptual narrowing appears to be a ubiquitous learning mechanism that contributes to language acquisition. PMID:22277043

  7. Meeting report for the 1st skin microbiota workshop, boulder, CO October 15-16 2012

    PubMed Central

    2014-01-01

    This report details the outcome of the 1st Skin Microbiota Workshop, Boulder, CO, held on October 15th-16th 2012. The workshop was arranged to bring Department of Defense personnel together with experts in microbial ecology, human skin physiology and anatomy, and computational techniques for interrogating the microbiome to define research frontiers at the intersection of these important areas. The workshop outlined a series of questions and created several working groups to address those questions, specifically to promote interdisciplinary activity and potential future collaboration. The US Army provided generous grant support and the meeting was organized and hosted by the University of Colorado at Boulder. A primary forward vision of the meeting was the importance of understanding skin microbial communities to improve the health and stealth of US Army warfighters.

  8. 1st ESMO Consensus Conference in lung cancer; Lugano 2010: small-cell lung cancer.

    PubMed

    Stahel, R; Thatcher, N; Früh, M; Le Péchoux, C; Postmus, P E; Sorensen, J B; Felip, E

    2011-09-01

    The 1st ESMO Consensus Conference on lung cancer was held in Lugano, Switzerland on 21st and 22nd May 2010 with the participation of a multidisciplinary panel of leading professionals in pathology and molecular diagnostics and medical, surgical and radiation oncology. Before the conference, the expert panel prepared clinically relevant questions concerning five areas as follows: early and locally advanced non-small-cell lung cancer (NSCLC), first-line metastatic NSCLC, second-/third-line NSCLC, NSCLC pathology and molecular testing, and small-cell lung cancer (SCLC) to be addressed through discussion at the Consensus Conference. All relevant scientific literature for each question was reviewed in advance. During the Consensus Conference, the panel developed recommendations for each specific question. The consensus agreement in SCLC is reported in this article. The recommendations detailed here are based on an expert consensus after careful review of published data. All participants have approved this final update.

  9. 4th generation of the 1st level surface detector trigger in the Pierre Auger Observator

    NASA Astrophysics Data System (ADS)

    Szadkowski, Z.

    The proposal of a new 4th generation of the Front-End with the advanced 1st level triggers for the Infill Array of the Pierre Auger Observatory and for the Auger North is described. Newest FPGA chips offer much higher capacity of logic registers and memories, as well as DSP blocks. The calibration channel, previously supported by an external dual-port RAM, has been fully implemented into FPGA chip, through a large internal memory. In turn DSP blocks allowed on implementation of much more sophisticated spectral trigger algorithms. A single chip simplified board design, newer architecture of FPGA reduced resouces utilization and power consumption. Higher sampling in the new Front- End in comparison with previous 40 MHz designs as well as free resources for new detection algotithms can be a good platform for CR radio detection technique at Auger enhancing a duty cycle for the detection of UHECR’s.

  10. [The 1st International Youth Ecologist Forum in China, 2009: a review].

    PubMed

    Xiong, You-cai; Xiong, Jun-lan; Li, Pu-fang; Li, Zhi-hua; Kong, Hai-yan; Wang, Shao-ming

    2011-04-01

    To promote the communication and cooperation between Chinese and overseas youth ecologists, a conference entitled "The 1st International Young Ecologist Forum" was held at Lanzhou University in June 29-30, 2009. This conference was organized by outstanding overseas ecologists and hosted by Lanzhou University. The presentations covered broad areas of ecology, including plant-soil interactions, structure and function of regional ecosystems, ecological security and ecological planning, global change ecology, and environmental sustainability, demonstrating that the development of China ecology is gradually from traditional basic research transforming into applied research. The presentations also reflected in some extent the development characteristics, evolution direction, and distribution pattern of China ecological research. China ecological research has gradually formed four centers, the Northeast, North, Northwest, and Southeast China, and each of them has its definite regional characteristics. Some suggestions about the organization form and future planning of the forum were put forward.

  11. Experiment attributes to establish tube with twisted tape insert performance cooling plasma facing components

    DOE PAGES

    Clark, Emily; Ramirez, Emilio; Ruggles, Art E.; Griffard, Cory

    2015-08-18

    The modeling capability for tubes with twisted tape inserts is reviewed with reference to the application of cooling plasma facing components in magnetic confinement fusion devices. The history of experiments examining the cooling performance of tubes with twisted tape inserts is reviewed with emphasis on the manner of heating, flow stability limits and the details of the test section and fluid delivery system. Models for heat transfer, burnout, and onset of net vapor generation in straight tube flows and tube with twisted tape are compared. As a result, the gaps in knowledge required to establish performance limits of the plasmamore » facing components are identified and attributes of an experiment to close those gaps are presented.« less

  12. High average power CW FELs (Free Electron Laser) for application to plasma heating: Designs and experiments

    SciTech Connect

    Booske, J.H.; Granatstein, V.L.; Radack, D.J.; Antonsen, T.M. Jr.; Bidwell, S.; Carmel, Y.; Destler, W.W.; Latham, P.E.; Levush, B.; Mayergoyz, I.D.; Zhang, Z.X. . Lab. for Plasma Research); Freund, H.P. )

    1989-01-01

    A short period wiggler (period {approximately} 1 cm), sheet beam FEL has been proposed as a low-cost source of high average power (1 MW) millimeter-wave radiation for plasma heating and space-based radar applications. Recent calculation and experiments have confirmed the feasibility of this concept in such critical areas as rf wall heating, intercepted beam ( body'') current, and high voltage (0.5 - 1 MV) sheet beam generation and propagation. Results of preliminary low-gain sheet beam FEL oscillator experiments using a field emission diode and pulse line accelerator have verified that lasing occurs at the predicted FEL frequency. Measured start oscillation currents also appear consistent with theoretical estimates. Finally, we consider the possibilities of using a short-period, superconducting planar wiggler for improved beam confinement, as well as access to the high gain, strong pump Compton regime with its potential for highly efficient FEL operation.

  13. Distinguishing cause from correlation in tokamak experiments to trigger edge-localised plasma instabilities

    SciTech Connect

    Webster, Anthony J.

    2014-11-15

    The generic question is considered: How can we determine the probability of an otherwise quasi-random event, having been triggered by an external influence? A specific problem is the quantification of the success of techniques to trigger, and hence control, edge-localised plasma instabilities (ELMs) in magnetically confined fusion (MCF) experiments. The development of such techniques is essential to ensure tolerable heat loads on components in large MCF fusion devices, and is necessary for their development into economically successful power plants. Bayesian probability theory is used to rigorously formulate the problem and to provide a formal solution. Accurate but pragmatic methods are developed to estimate triggering probabilities, and are illustrated with experimental data. These allow results from experiments to be quantitatively assessed, and rigorously quantified conclusions to be formed. Example applications include assessing whether triggering of ELMs is a statistical or deterministic process, and the establishment of thresholds to ensure that ELMs are reliably triggered.

  14. 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.

  15. 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.

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

    DOE PAGES

    Garrison, L. M.; Zenobia, Samuel J.; Egle, Brian J.; Kulcinski, Gerald L.; Santarius, John 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 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 × 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. 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

  17. 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. PMID:27587118

  18. Ion probe beam experiments and kinetic modeling in a dense plasma focus Z-pinch

    SciTech Connect

    Schmidt, A. Ellsworth, J. Falabella, S. Link, A. McLean, H. Rusnak, B. Sears, J. Tang, V.; Welch, D.

    2014-12-15

    The Z-pinch phase of a dense plasma focus (DPF) emits multiple-MeV ions in a ∼cm length. The mechanisms through which these physically simple devices generate such high energy beams in a relatively short distance are not fully understood. We are exploring the origins of these large gradients using measurements of an ion probe beam injected into a DPF during the pinch phase and the first kinetic simulations of a DPF Z-pinch. To probe the accelerating fields in our table top experiment, we inject a 4 MeV deuteron beam along the z-axis and then sample the beam energy distribution after it passes through the pinch region. Using this technique, we have directly measured for the first time the acceleration of an injected ion beam. Our particle-in-cell simulations have been benchmarked on both a kJ-scale DPF and a MJ-scale DPF. They have reproduced experimentally measured neutron yields as well as ion beams and EM oscillations which fluid simulations do not exhibit. Direct comparisons between the experiment and simulations enhance our understanding of these plasmas and provide predictive design capability for accelerator and neutron source applications.

  19. Ion probe beam experiments and kinetic modeling in a dense plasma focus Z-pinch

    NASA Astrophysics Data System (ADS)

    Schmidt, A.; Ellsworth, J.; Falabella, S.; Link, A.; McLean, H.; Rusnak, B.; Sears, J.; Tang, V.; Welch, D.

    2014-12-01

    The Z-pinch phase of a dense plasma focus (DPF) emits multiple-MeV ions in a ˜cm length. The mechanisms through which these physically simple devices generate such high energy beams in a relatively short distance are not fully understood. We are exploring the origins of these large gradients using measurements of an ion probe beam injected into a DPF during the pinch phase and the first kinetic simulations of a DPF Z-pinch. To probe the accelerating fields in our table top experiment, we inject a 4 MeV deuteron beam along the z-axis and then sample the beam energy distribution after it passes through the pinch region. Using this technique, we have directly measured for the first time the acceleration of an injected ion beam. Our particle-in-cell simulations have been benchmarked on both a kJ-scale DPF and a MJ-scale DPF. They have reproduced experimentally measured neutron yields as well as ion beams and EM oscillations which fluid simulations do not exhibit. Direct comparisons between the experiment and simulations enhance our understanding of these plasmas and provide predictive design capability for accelerator and neutron source applications.

  20. Simulations of high energy density plasma physics and laboratory astrophysics experiments

    NASA Astrophysics Data System (ADS)

    Chittenden, J. P.; Marocchino, A.; Lebedev, S. V.; Smith, R. A.; Ciardi, A.; Jennings, C. A.

    2008-04-01

    We show how 3D resistive MHD simulations can be used in the design and interpretation of Laboratory Astrophysics and High Energy Density Plasma Physics experiments at Imperial College, Sandia National Laboratory and Centre d'Etudes de Gramat. Using pulsed power generators to drive conical wire arrays, provides a mechanism of generating radiatively cooled hypersonic jets which model the interaction of jets from young stellar objects with the ISM and the deflection of these jets by side-winds. Radial wire arrays can be used to study magnetically launched jets, the effects of field topology on jet stability and episodic jets. Radial arrays also represent a high intensity compact radiation source, with potential applications to inertial confinement fusion. The collision of a magnetically accelerated foil with a gaseous target can be used to study of shock waves with strong radiative cooling. The interaction of a short pulse laser with cluster media can generate expanding blast waves in high energy density plasmas. Simulations of experiments with two cylindrical expanding blast waves, show the evolution of a complex 3D Mach stem, which can be compared to tomographic experimental data.

  1. Core turbulent transport in tokamak plasmas: bridging theory and experiment with QuaLiKiz

    NASA Astrophysics Data System (ADS)

    Bourdelle, C.; Citrin, J.; Baiocchi, B.; Casati, A.; Cottier, P.; Garbet, X.; Imbeaux, F.; Contributors, JET

    2016-01-01

    Nonlinear gyrokinetic codes allow for detailed understanding of tokamak core turbulent transport. However, their computational demand precludes their use for predictive profile modeling. An alternative approach is required to bridge the gap between theoretical understanding and prediction of experiments. A quasilinear gyrokinetic model, QuaLiKiz (Bourdelle et al 2007 Phys. Plasmas 14 112501), is demonstrated to be rapid enough to ease systematic interface with experiments. The derivation and approximation of this approach are reviewed. The quasilinear approximation is proven valid over a wide range of core plasma parameters. Examples of profile prediction using QuaLiKiz coupled to the CRONOS integrated modeling code (Artaud et al 2010 Nucl. Fusion 50 043001) are presented. QuaLiKiz is being coupled to other integrated modeling platforms such as ETS and JETTO. QuaLiKiz quasilinear gyrokinetic turbulent heat, particle and angular momentum fluxes are available to all users. It allows for extensive stand-alone interpretative analysis and for first principle based integrated predictive modeling.

  2. Using radiation temperature to monitor plasma drive in materials strength experiments

    NASA Astrophysics Data System (ADS)

    Benedetti, Laura Robin; Moore, A. S.; Park, H.-S.; Prisbrey, S. T.; Huntington, C. M.; McNaney, J. M.; Smith, R.; Wehrenberg, C. E.; Remington, B. A.; Arsenlis, A.

    2015-11-01

    Materials strength experiments at the National Ignition Facility generate smooth loading in a material by the plasma drive of a shocked reservoir mounted on the side of a gold hohlraum. In these experiments, the loading profile of plasma unloading across a gap and then stagnating at the target is measured with VISAR. Geometric limitations preclude simultaneous measurement of VISAR and the Rayleigh-Taylor (RT) growth that is used to determine strength. We use hohlraum radiation temperatures measured with the Dante spectrometer to link the drive measured with VISAR to the stress condition when RT growth is measured. By combining Dante measurements from two different lines of sight with view factor calculations, we infer the radiation drive into the reservoir. With this method, we can account for spatial variations within the hohlraum and also reproduce observed variations due to changes in pointing and target orientation. We describe the simplified, physics-based analysis of Dante spectra and the methods of determining radiation drive to the reservoir. We then discuss the effectiveness of this method for inferring drive at the target material. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344. LLNL-ABS-674966.

  3. Pre-Stage Magnetic Coil to Enhance Helicon Mode Excitation on a Small Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    Schlank, Carter; James, Royce; Thayer, Nicholas; Sherman, Justin; Nolan, Stephen; Lopez, Michael

    2012-10-01

    Small helicon plasmas have been employed in various capacities from industry to spacecraft propulsion. At the Coast Guard Academy Plasma Lab (CGAPL), a small Helicon Plasma Experiment (HPX) is being developed to utilize the reputed high density (10^13 cm-3 and higher) at low pressure (.01 T) [1] Helicon Mode Plasmas. HPX will become a high temperature and density diagnostic development test-bed for future laboratory investigations in addition to becoming a tool for future spacecraft propulsion devices. HPX Plasmas are created by imparting directed energy into a Pyrex tube preloaded with Ar gas with fill pressures on the order of 10^4 mTorr utalizing a power supply and matching box can deliver up 250 W of power in a 20 MHz to 100 MHz frequency range. It has been demonstrated [1] that a uniform magnetic field in lower energy level plasmas can facilitate a decrease in inertial effects, which promotes energy conservation within the plasma and provids the necessary external energy in the plasma's magnetic field to reach the Helicon Mode. HPX employes an electromagnet to establish this uniform field. An acceleration coil, currently under construction, will be used to increase the plasma velocity to facilitate partcle and optical probing within the vacuum chamber for experimental analysis. Initial accuracy and calibration measurements of the relative magnetic fields created by both electromagnets will be reported.[0pt][1] K. Toki, et al., Thin Solid Films 506-507 (2005).

  4. Plasma density from Cerenkov radiation, betatron oscillations, and beam steering in a plasma wakefield experiment at 30 GeV

    SciTech Connect

    Catravas, P.; Chattopadhyay, S.; Esarey, E.; Leemans, W.P.; Assmann, R.; Decker, F.-J.; Hogan, M.J.; Iverson, R.; Siemann, R.H.; Walz, D.; Whittum, D.; Blue, B.; Clayton, C.; Joshi, C.; Marsh, K.; Mori, W.B.; Wang, S.; Katsouleas, T.; Lee, S.; Muggli, P.

    2001-01-01

    A method for using Cerenkov radiation near atomic spectral lines to measure plasma source properties for plasma wakefield applications has been discussed and experimentally verified. Because the radiation co-propagates with the electron beam, the radiation samples the source properties exactly along the path of interest with perfect temporal synchronization. Observation wavelengths were chosen with respect to the atomic resonances of the plasma source, where the relative change in the index of refraction strongly affects the Cerenkov cone angle, and permits flexible diagnostic design. The Cerenkov spatial profiles were systematically studied for a Lithium heat pipe oven as a function of oven temperature and observation wavelength. Neutral densities and plasma densities were extracted from the measurements.

  5. Effect of milk feed source, frequency of feeding and age at turnout on calf performance, live-weight at mating and 1st lactation milk production

    PubMed Central

    2012-01-01

    Female calves (n = 108) were assigned to 6 cold milk feeding treatments in two experiments for a 70-day period. Live-weight (LW) was measured weekly, with an additional LW taken at day 410 and post-calving for animals in experiment 1. In Experiment 1, the effect of feeding frequency and age of turnout to pasture on calf performance and 1st lactation milk yields were evaluated. The whole milk (WM) feeding treatments applied were (i) once daily feeding (OD), (ii) twice daily feeding (TD), (iii) OD feeding, outdoors at 38 days (ODO). In Experiment 2, the effects of feeding milk replacer (MR) as opposed to WM and age of turnout to pasture on calf performance were evaluated. The treatments applied were (i) OD feeding with WM (OD), (ii) OD feeding with milk replacer (MR) (ODMR), (iii) OD feeding with MR, outdoors at 38 days (ODMRO). Experiment 1: There were no differences (P > 0.05) in LW or average daily gain between TD and OD calves at day 80 or 410. ODO calves had lower LW at day 80 as compared to OD or TD (P < 0.001). Calf LW at day 80 was 86, 89 and 85 kg and at day 410 was 304, 309 and 316 kg for OD, TD and ODO, respectively. Milk feeding frequency or time of calf turnout had no effect on LW post calving, milk composition or 1st lactation milk yields. Experiment 2: Total LW at day 80 was higher (P < 0.05) for ODMR compared to OD or ODMRO calves. Calf LW was 87, 95, and 88 kg for OD, ODMR and ODMRO, respectively. However, LW at day 410 did not differ between treatments. This study showed that while some differences were observed in calf LW at day 80, these differences had no effect on LW at day 410 or 1st lactation milk yield. It can be concluded that calves can be successfully reared when fed OD with WM or MR, indoors and when turned out to pasture at 38 days of age. PMID:23078871

  6. A Next-Generation Experiment To Study Magnetic Reconnection and Related Explosive Phenomena in Large and Collisionless Plasmas

    NASA Astrophysics Data System (ADS)

    Ji, H.; Yamada, M.; Prager, S.; Daughton, W.; Roytershteyn, V.

    2009-11-01

    Magnetic reconnection, a topological change in magnetic field in plasmas, often occurs explosively leading to rapid conversion of magnetic energy to plasma particle energy in space, astrophysical and laboratory fusion plasmas. The Magnetic Reconnection Experiment (MRX, http://mrx.pppl.gov) is a primary dedicated experiment to study reconnection in a controlled environment. However, further critical understanding and contributions to space and astrophysical plasmas are limited by the parameters achievable in MRX and other dedicated experiments. The MRX plasmas are relatively collisional (Lundquist numbers S ˜10^3) and effectively small (plasma size normalized by ion skin depth or ion sound radius ˜10). In this paper, we discuss plans for a next-generation reconnection experiment based on MRX. By a combination of larger physical size, stronger magnetic field, and higher heating power, we aim to increase S by a factor of 100 and effective size by a factor of 10, representing a very large jump in the laboratory capabilities. Kinetic simulations in realistic boundaries will be used to guide the experimental design. Research topics include: (1) transition of collisional to collisionless reconnection and its scaling with collisionality and size, (2) interacting multiple reconnections as a possible cause of explosive phenomena, (3) particle energization by reconnection, (4) relation between local reconnection and global magnetic self-organization in 3D realistic geometry and boundary.

  7. Stereolithography based method of creating custom gas density profile targets for high intensity laser-plasma experiments.

    PubMed

    Jolly, S W; He, Z; McGuffey, C; Schumaker, W; Krushelnick, K; Thomas, A G R

    2012-07-01

    Laser based stereolithography methods are shown to be useful for production of gas targets for high intensity laser-plasma interaction experiments. A cylindrically symmetric nozzle with an opening of approximately 100 μm and a periodic attachment of variable periodicity are outlined in detail with associated density profile characterization. Both components are durable within the limits of relevant experiments.

  8. Numerical Experiments on Oxygen Plasma Focus: Scaling Laws of Soft X-Ray Yields

    NASA Astrophysics Data System (ADS)

    Akel, M.

    2013-08-01

    Numerical experiments have been investigated on UNU/ICTP PFF low energy plasma focus device with oxygen filling gas. In these numerical experiments, the temperature window of 119-260 eV has been used as a suitable temperature range for generating oxygen soft X-rays. The Lee model was applied to characterize the UNU/ICTP PFF plasma focus. The optimum soft X-ray yield (Ysxr) was found to be 0.75 J, with the corresponding efficiency of about 0.03 % at pressure of 2.36 Torr and the end axial speed was va = 5 cm/μs. The practical optimum combination of p0, z0 and `a' for oxygen Ysxr was found to be 0.69 Torr, 4.8 cm and 2.366 cm respectively, with the outer radius b = 3.2 cm. This combination gives Ysxr ~ 5 J, with the corresponding efficiency of about 0.16 %. Thus we expect to increase the oxygen Ysxr of UNU/ICTP PFF, without changing the capacitor bank, merely by changing the electrode configuration and operating pressure. Scaling laws on oxygen soft X-ray yield, in terms of storage energies E0, peak discharge current Ipeak and focus pinch current Ipinch were found over the range from 1 kJ to 1 MJ. It was found that the oxygen soft X-ray yields scale well with and for the low inductance (L0 = 30 nH) (where yields are in J and currents in kA). While the soft X-ray yield scaling laws in terms of storage energies were found to be as (E0 in kJ and Ysxr in J) with the scaling showing gradual deterioration as E0 rises over the range. The oxygen soft X-ray yield emitted from plasma focus is found to be about 8.7 kJ for storage energy of 1 MJ. The optimum efficiency for soft X-ray yield (1.1 %) is with capacitor bank energy of 120 kJ. This indicates that oxygen plasma focus is a good soft X-ray source when properly designed.

  9. Progress towards high performance plasmas in the National Spherical Torus Experiment (NSTX)

    SciTech Connect

    Kaye, S. M.; Bell, M. G.; Bell, R. E.; Bernabei, S; Bialek, J.; Biewer, T.; Blanchard, W.; Boedo, J.; Bush, C.; Carter, M. D.; Choe, W.; Crocker, N.; Darrow, D. S.; Davis, W.; Delgado-Aparicio, L.; Diem, S.; Ferron, J.; Field, A.; Foley, J.; Fredrickson, E. D.; Gates, D. A.; Gibney, T.; Harvey, R.; Hatcher, R. E.; Heidbrink, W.; Hill, K.; Hosea, J. C.; Jarboe, T. R.; Johnson, D. W.; Kaita, R.; Kessel, C.; Kubota, S.; Kugel, H. W.; Lawson, J.; LeBlanc, B. P.; Lee, K. C.; Levinton, F.; Maingi, R.; Manickam, J.; Maqueda, R.; Marsala, R.; Mastrovito, D.; Mau, T. K.; Medley, S. S.; Menard, J.; Meyer, H.; Mikkelsen, D. R.; Mueller, D.; Munsat, T.; Nelson, B. A.; Neumeyer, C.; Nishino, N.; Ono, M.; Park, H.; Park, W.; Paul, S.; Peebles, T.; Peng, M.; Phillips, C.; Pigarov, A.; Pinsker, R.; Ram, A.; Ramakrishnan, S.; Raman, R.; Rasmussen, D.; Redi, M.; Rensink, M.; Rewoldt, G; Robinson, J.; Roney, P.; Roquemore, A. L.; Ruskov, E; Ryan, P.; Sabbagh, S. A.; Schneider, H.; Skinner, C. H.; Smith, D. R.; Sontag, A.; Soukhanovskii, V.; Stevenson, T.; Stotler, D.; Stratton, B.; Stutman, D.; Swain, D.; Synakowski, E.; Takase, Y.; Taylor, G.; Tritz, K.; Halle, A. von; Wade, M.; White, R.; Wilgen, J.; Williams, M.; Wilson, J. R.; Zhu, W.; Zweben, S. J.; Akers, R.; Beiersdorfer, P.; Betti, R.; Bigelow, T.; Bitter, M.; Bonoli, P.; Bourdelle, C.; Chang, C. S.; Chrzanowski, J.; Domier, C.; Dudek, L.; Efthimion, P. C.; Finkenthal, M.; Fredd, E.; Fu, G. Y.; Glasser, A.; Goldston, R. J.; Greenough, N. L.; Grisham, L. R.; Gorelenkov, N.; Guazzotto, L.; Hawryluk, R. J.; Hogan, J.; Houlberg, W.; Humphreys, D.; Jaeger, F.; Kalish, M.; Krasheninnikov, S.; Lao, L. L.; Lawrence, J.; Leuer, J.; Liu, D.; Luhmann, N. C.; Mazzucato, E.; Oliaro, G.; Pacella, D.; Parsells, R.; Schaffer, M.; Semenov, I.; Shaing, K. C.; Shapiro, M. A.; Shinohara, K.; Sichta, P.; Tang, X.; Vero, R.; Walker, D.; Wampler, W.

    2005-10-01

    The major objective of the National Spherical Torus Experiment (NSTX) is to understand basic toroidal confinement physics at low aspect ratio and high βT in order to advance the spherical torus (ST) concept. In order to do this, NSTX utilizes up to 7.5 MW of neutral beam injection, up to 6 MW of high harmonic fast waves (HHFWs), and it operates with plasma currents up to 1.5 MA and elongations of up to 2.6 at a toroidal field up to 0.45 T. New facility, and diagnostic and modeling capabilities developed over the past two years have enabled the NSTX research team to make significant progress towards establishing this physics basis for future ST devices. Improvements in plasma control have led to more routine operation at high elongation and high βT (up to ~40%) lasting for many energy confinement times. βT can be limited by either internal or external modes. The installation of an active error field (EF) correction coil pair has expanded the operating regime at low density and has allowed for initial resonant EF amplification experiments. The determination of the confinement and transport properties of NSTX plasmas has benefited greatly from the implementation of higher spatial resolution kinetic diagnostics. The parametric variation of confinement is similar to that at conventional aspect ratio but with values enhanced relative to those determined from conventional aspect ratio scalings and with a βT dependence. The transport is highly dependent on details of both the flow and magnetic shear. Core turbulence was measured for the first time in an ST through correlation reflectometry. Non-inductive start-up has been explored using PF-only and transient co-axial helicity injection techniques, resulting in up to 140 kA of toroidal current generated by the latter technique. Calculated bootstrap and beam-driven currents have sustained up to 60% of the flat-top plasma current in NBI discharges. Studies of HHFW absorption

  10. Diagnostic suite of the C-2U advanced beam-driven field-reversed configuration plasma experiment

    NASA Astrophysics Data System (ADS)

    Thompson, M. C.; Gota, H.; Putvinski, S.; Tuszewski, M.; Binderbauer, M.

    2016-11-01

    The C-2U experiment at Tri Alpha Energy studies the evolution of field-reversed configuration (FRC) plasmas sustained by neutral beam injection. Data on the FRC plasma performance are provided by a comprehensive suite of diagnostics that includes magnetic sensors, interferometry, Thomson scattering, spectroscopy, bolometry, reflectometry, neutral particle analyzers, and fusion product detectors. While many of these diagnostic systems were inherited from the preceding experiment C-2, C-2U has a variety of new and upgraded diagnostic systems: multi-chord far-infrared polarimetry, multiple fast imaging cameras with selectable atomic line filters, proton detector arrays, and 100 channel bolometer units capable of observing multiple regions of the spectrum simultaneously. In addition, extensive ongoing work focuses on advanced methods of measuring separatrix shape and plasma current profile that will facilitate equilibrium reconstruction and active control of the FRC plasma.

  11. Development of a radio frequency ion source with multi-helicon plasma injectors for neutral beam injection system of Versatile Experiment Spherical Torus

    SciTech Connect

    Choe, Kyumin; Jung, Bongki; Chung, Kyoung-Jae; Hwang, Y. S.

    2014-02-15

    Despite of high plasma density, helicon plasma has not yet been applied to a large area ion source such as a driver for neutral beam injection (NBI) system due to intrinsically poor plasma uniformity in the discharge region. In this study, a radio-frequency (RF) ion source with multi-helicon plasma injectors for high plasma density with good uniformity has been designed and constructed for the NBI system of Versatile Experiment Spherical Torus at Seoul National University. The ion source consists of a rectangular plasma expansion chamber (120 × 120 × 120 mm{sup 3}), four helicon plasma injectors with annular permanent magnets and RF power system. Main feature of the source is downstream plasma confinement in the cusp magnetic field configuration which is generated by arranging polarities of permanent magnets in the helicon plasma injectors. In this paper, detailed design of the multi-helicon plasma injector and plasma characteristics of the ion source are presented.

  12. Plasma Current Start-up Experiment using Waves in the Lower Hybrid Frequency Range in TST-2

    SciTech Connect

    Takase, Y.; Wakatsuki, T.; Ejiri, A.; Kakuda, H.; Ambo, T.; Hanashima, K.; Hiratsuka, J.; Nagashima, Y.; Sakamoto, T.; Shino, R.; Sonehara, M.; Watanabe, O.; Yamaguchi, T.; Moeller, C. P.; Kasahara, H.; Kumazawa, R.; Saito, K.; Seki, T.; Shimpo, F.

    2011-12-23

    Noninductive plasma current (I{sub p}) start-up experiments using RF power in the lower hybrid frequency range are being conducted on the TST-2 spherical tokamak. The lower hybrid wave (LHW) has demonstrated efficient current drive in conventional tokamaks. However, in spherical tokamak (ST) plasmas with very high dielectric constants (;{epsilon}{approx}{omega}{sub pe}{sup 2}/{Omega}{sub e}{sup 2}>>1), accessibility of the LHW to the plasma core is severely limited. Our approach is to keep the plasma density low (such that {epsilon}{approx}1) during I{sub p} ramp-up. Once I{sub p} reaches a level sufficiently high for neutral beam current drive, plasma can be densified and transformed into an advanced tokamak plasma dominated by the self-driven bootstrap current. Initial plasma start-up experiments were performed on TST-2 using a combline antenna which excites a traveling fast wave. After formation of toroidal flux surfaces, RF power and vertical field were ramped up to increase I{sub p}. Up to 12 kA of Ip has been obtained by this method. Soft X-ray measurements indicate that the electron temperature increases as I{sub p} increases, and hard X-ray spectroscopy indicates that energetic electrons build up as I{sub p} is ramped up.

  13. Observation of nonlinear wave decay processes in the solar wind by the AMPTE IRM plasma wave experiment

    NASA Technical Reports Server (NTRS)

    Koons, H. C.; Roeder, J. L.; Bauer, O. H.; Haerendel, G.; Treumann, R.

    1987-01-01

    Nonlinear wave decay processes have been detected in the solar wind by the plasma wave experiment aboard the Active Magnetospheric Particle Tracer Explorers (AMPTE) IRM spacecraft. The main process is the generation of ultralow-frequency ion acoustic waves from the decay of Langmuir waves near the electron plasma frequency. Frequently, this is accompanied by an enhancement of emissions near twice the plasma frequency. This enhancement is most likely due to the generation of electromagnetic waves from the coalescence of two Langmuir waves. These processes occur within the electron foreshock in front of the earth's bow shock.

  14. First results of LHCD experiments with 4.6 GHz system toward steady-state plasma in EAST

    NASA Astrophysics Data System (ADS)

    Liu, F. K.; Ding, B. J.; Li, J. G.; Wan, B. N.; Shan, J. F.; Wang, M.; Liu, L.; Zhao, L. M.; Li, M. H.; Li, Y. C.; Yang, Y.; Wu, Z. G.; Feng, J. Q.; Hu, H. C.; Jia, H.; Huang, Y. Y.; Wei, W.; Cheng, M.; Xu, L.; Zang, Q.; Lyu, B.; Lin, S. Y.; Duan, Y. M.; Wu, J. H.; Peysson, Y.; Decker, J.; Hillairet, J.; Ekedahl, A.; Luo, Z. P.; Qian, J. P.; Shen, B.; Gong, X. Z.; Hu, L. Q.; the EAST Team

    2015-11-01

    A 4.6 GHz lower-hybrid current drive (LHCD) system has been firstly commissioned in EAST in the 2014 campaign. The first LHCD results with 4.6 GHz show that LHW can be coupled to plasma with a low reflection coefficient, drive plasma current and plasma rotation, modify the plasma current profile, and heat plasma effectively. By means of configuration optimization and local gas puffing near the LHW antenna, good LHW-plasma coupling with a reflection coefficient less than 5% is obtained. The maximum LHW power coupled to plasma is up to 3.5 MW. The current drive (CD) efficiency is up to 1.1  ×  1019 A m-2 W-1 and the central electron temperature is above 4 keV, suggesting that LH power could be mainly deposited in the core region, which is in agreement with code simulation. Experiments show that the current profile is effectively modified and toroidal rotation in the co-current direction is driven by the LHCD. Also, the CD efficiency and current profile depend on the launched wave spectrum, suggesting the possibility of controlling the current profile by changing the phase difference. Repeatable H-mode plasma is obtained by either the 4.6 GHz LHCD system alone, or together with a 2.45 GHz LHCD system, the NBI (neutral beam injection) system. The different ELM features of H-mode between the different heating methods are under investigation.

  15. Drift Wave Chaos and Turbulence in a LAPTAG Plasma Physics experiment

    NASA Astrophysics Data System (ADS)

    Katz, Cami; Gekelman, Walter; Pribyl, Patrick; Wise, Joe; Birge-Lee, Henry; Baker, Bob; Marmie, Ken; Thomas, Sam; Buckley-Bonnano, Samuel

    2015-11-01

    Whenever there is a pressure gradient in a magnetized plasma drift waves occur spontaneously. Drift waves have density and electrical potential fluctuations but no self magnetic field. In our experiment the drift waves form spontaneously in a narrow plasma column. (ne = 5 ×1011 cm3 , Te = 5 eV , B = 200 Gauss, dia = 25 cm , L = 1 . 5 m). As the drift waves grow from noise simple averaging techniques cannot be used to map them out in space and time. The ion saturation current Isat n√{Te} is recorded for an ensemble of 50 shots on a fixed probe located on the density gradient and for a movable probe. The probe signals are not sinusoidal and are filtered to calculate the cross-spectral function CSF = ∫ ∑ nshot Ifix, ωr->1 , tImov , ω (r->1 + δr-> , t + τ) dt , which can be used to extract the temporal and spatially varying wave patterns. The dominant wave at 18 kHz is a rotating spiral with m =2. LAPTAG is a university-high school alliance outreach program, which has been in existence for over 20 years. Work done at the BaPSF and supported by NSF/DOE.

  16. Current halo structures in high-current plasma experiments: {theta}-pinch

    SciTech Connect

    Matveev, Yu. V.

    2007-03-15

    Experimental data elucidating mechanisms for halo formation in {theta}-pinch discharges are presented and discussed. The experiments were performed with different gases (H{sub 2}, D{sub 2}, He, and Ar) in a theta-pinch device with a porcelain vacuum chamber and an excitation coil 15 cm in diameter and 30 cm in length. The stored energy, the current in the excitation coil, and the current half-period were W = 10 kJ, I = 400 kA, and T/2 = 14 {mu}s, respectively. It is found that the plasma rings (halos) surrounding the pinch core arise as a result of coaxial pinch stratification due to both the excitation of closed currents (inductons) inside the pinch and the radial convergence of the plasma current sheaths produced after the explosion of T-layers formed near the wall in the initial stage of the discharge. It is concluded that halo structures observed in pinches, tokamaks, and other high-current devices used in controlled fusion research have the same nature.

  17. The National Spherical Tokamak Experiment at the Princeton Plasma Physics Laboratory

    SciTech Connect

    1995-12-01

    The Department of Energy (DOE) has prepared an Environmental Assessment (EA), DOE/EA-1108, evaluating the environmental effects of the proposed construction and operation of the National Spherical Tokamak Experiment (NSTX) within the existing C-Stellarator (CS) Building at the Princeton Plasma Physics Laboratory, Princeton, New Jersey. The purpose of the NSTX is to investigate the physics of spherically shaped plasmas as an alternative path to conventional tokamaks for development of fusion energy. Fusion energy has the potential to help compensate for dwindling supplies of fossil fuels and the eventual depletion of fissionable uranium used in present-day nuclear reactors. Construction of the NSTX in the CS Building would require the dismantling and removal of the existing unused Princeton Large Torus (PLT) device, part of which would be reused to construct the NSTX. Based on the analyses in the EA, the DOE has determined that the proposed action does not constitute a major federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969, 42 U.S.C. 4,321 et seq. The preparation of an Environmental Impact Statement is not required. Thus, the DOE is issuing a FONSI pursuant to the Council on Environmental Quality regulations implementing NEPA (40 CFR Parts 1500--1508) and the DOE NEPA implementing regulations (10 CFR Part 1021).

  18. Plasma waves produced by an ion beam: Observations by the VLF experiment on Porcupine

    NASA Astrophysics Data System (ADS)

    Jones, D.

    1980-06-01

    Results are presented from the VLF electric field experiments flown on Porcupine flights F3 and F4, which also had ejectable xenon ion sources. The xenon ion beam was found to produce plasma instabilities whose frequencies could be linked to the local proton gyrofrequency. The main energy in the instabilities lies at 3kHz for events when the Xe+ source is close to the rocket, and at 7kHz when the source is farther away. Theory predicts that these frequencies should be the lower-hybrid-resonance and this implies that Xe+ is the dominant ion in the first case and that it is the ambient plasma that dominates later. There is no discernable antenna spin-modulation during the Xe events which indicates that the wave k-vectors are not unidirectional. A theory is cited based on the setting up of the proton cyclotron harmonic waves by the Xe+ or 0+ cyclotron harmonic waves. The second Xe+ event on both flights exhibited an, as yet, unexplained harmonic structure related to half the local proton gyrofrequency.

  19. Development of a Split Bitter-type Magnet System for Dusty Plasma Experiments

    NASA Astrophysics Data System (ADS)

    Bates, Evan; Romero-Talamas, Carlos A.; Birmingham, William J.; Rivera, William F.

    2014-10-01

    A 10 Tesla Bitter-type magnetic system is under development at the Dusty Plasma Laboratory of the University of Maryland, Baltimore County (UMBC). We present here an optimization technique that uses differential evolution to minimize the omhic heating produced by the coils, while constraining the magnetic field in the experimental volume. The code gives us the optimal dimensions for the coil system including: coil length, turn thickness, disks radii, resistance, and total current required for a constant magnetic field. Finite element parametric optimization is then used to establish the optimal design for water cooling holes. Placement of the cooling holes will also take into consideration the magnetic forces acting on the copper alloy disks to ensure the material strength is not compromised during operation. The proposed power and cooling water delivery subsystems for the coils are also presented. Upon completion and testing of the magnet system, planned experiments include the propagation of magnetized waves in dusty plasma crystals under various boundary conditions, and viscosity in rotational shear flow, among others.

  20. Experiments on dust transport in plasma to investigate the origin of the lunar horizon glow

    NASA Astrophysics Data System (ADS)

    Wang, X.; Horányi, M.; Robertson, S.

    2009-05-01

    Dust grains on the lunar surface are exposed to UV radiation and solar wind plasma and can collect electrical charges, leading to their possible lift-off and transport in the presence of near-surface electric fields. Motivated by the long-standing open questions about the physics of electrostatic lunar dust transport, we investigated the dynamics of dust grains on a conducting surface in a laboratory plasma. The dust used in these experiments was a nonconducting JSC-Mars-1 sample with particle size of less than 25 microns. We found that dust grains placed on a conducting surface, which is biased more negatively than its floating potential, charge positively, and an initial pile spreads to form a dust ring. Dust particles were observed to land on insulating blocks, indicating the height of their hopping motion. The measured electrostatic potential distribution above the dust pile shows that an outward pointing electric field near the edge of the pile is responsible for spreading the positively charged grains. A nonmonotonic potential dip was measured in the sheath above an insulating patch, indicating a localized upward electric field causing the dust lift-off from the surface. Faraday cup measurements showed that the grains near the boundary of the dust pile collect more charge than those closer to the center of the dust pile and can be more readily lifted and moved in the radial direction, leading to the formation of a spreading ring.

  1. Global Simulations of Dynamo and Magnetorotational Instability in Madison Plasma Experiments and Astrophysical Disks

    SciTech Connect

    Ebrahimi, Fatima

    2014-07-31

    Large-scale magnetic fields have been observed in widely different types of astrophysical objects. These magnetic fields are believed to be caused by the so-called dynamo effect. Could a large-scale magnetic field grow out of turbulence (i.e. the alpha dynamo effect)? How could the topological properties and the complexity of magnetic field as a global quantity, the so called magnetic helicity, be important in the dynamo effect? In addition to understanding the dynamo mechanism in astrophysical accretion disks, anomalous angular momentum transport has also been a longstanding problem in accretion disks and laboratory plasmas. To investigate both dynamo and momentum transport, we have performed both numerical modeling of laboratory experiments that are intended to simulate nature and modeling of configurations with direct relevance to astrophysical disks. Our simulations use fluid approximations (Magnetohydrodynamics - MHD model), where plasma is treated as a single fluid, or two fluids, in the presence of electromagnetic forces. Our major physics objective is to study the possibility of magnetic field generation (so called MRI small-scale and large-scale dynamos) and its role in Magneto-rotational Instability (MRI) saturation through nonlinear simulations in both MHD and Hall regimes.

  2. Kinetically driven Raman scattering in short, bi-speckle laser-plasma interaction experiments

    NASA Astrophysics Data System (ADS)

    Glize, Kevin; Rousseaux, Christophe; Baton, Sophie; Dervieux, Vincent; Lancia, Livia

    2015-11-01

    In order to investigate collective speckles behavior in laser-plasma interaction, bi-speckle experiments have been performed using the ELFIE facility (LULI). Two independent laser pulses (1.06 nm, 1.5 ps FWHM) interact with preformed He plasma (0.06 nc, 300 eV). The first beam drives stimulated Raman scattering, while the second, which its intensity is set near SRS threshold, is focused near the first one (typically 90 μm). The interaction, with crossed and parallel polarization, was studied for both variation of the time delay and the lateral distance between the two pulses, featuring a highly resolved Thomson-scattering diagnostic and backward Raman imaging. It is shown that the kinetic perturbations are of primary importance on triggering SRS in the weak speckle, which exhibits SRS instability up to an expectedly long time delay after the interaction of the strong one. The experimental results will be discussed with the help of 2D PIC simulations (CALDER code).

  3. Thermal Design of a Bitter-Type Electromagnet for Dusty Plasma Experiments: Prototype Design and Construction

    NASA Astrophysics Data System (ADS)

    Birmingham, W. J.; Bates, E. M.; Romero-Talamás, Carlos; Rivera, W. F.

    2015-11-01

    For the purpose of analyzing magnetized dusty plasma at the University of Maryland Baltimore County (UMBC) Dusty Plasma Laboratory, we are designing a resistive water cooled Bitter-Type electromagnet. When completed, the magnet will be programmable to generate fields of up to 10 T for at least 10 seconds and up to several minutes. An analytic thermal design method was developed for establishing the location of elongated axial cooling passages. Comparisons with finite element analysis (FEA) data reveals that the thermal design method was capable of generating cooling channel patterns which establish manageable temperature profiles within the magnet. With our analytic method, cooling hole patterns can be generated in seconds instead of hours with FEA software. To further validate our thermal analysis as well as manufacturing techniques of our magnet design, we are now constructing a prototype electromagnet. The prototype is designed to operate continuously at 1 T with a current of 750 A, and has four diagnostic ports that can accommodate thermocouples and optical access to the water flow. A 1.25 inch diameter bore allows for axial field measurements and provides space for small scale experiments. Thermal analysis and specifics of the electromagnet design are presented.

  4. Early MIMD experience with a plasma physics simulation program on the CRAY X-MP

    SciTech Connect

    Rhoades, C.E. Jr.

    1986-02-01

    This paper describes some early experience with converting a plasma physics simulation program to the CRAY X-MP, a current multiple instruction, multiple data (MIMD) computer consisting of two processors with architecture similar to that of the CRAY-1. The computer program used in this study is an all Fortran version of SELF, a two species, one space, two velocity, electromagnetic, Newtonian, particle in cell, plasma simulation code. The approach to converting SELF to use both processors of the CRAY X-MP is described in some detail. The resulting multiprocessor version of SELF is nearly a factor of two faster in real time than the single processor version. The multiprocessor version obtains 58.2+-.1 seconds of central processor time in 30+-.5 seconds of real time. For comparison, the CRAY-1 execution time if 74.5 seconds. For SELF, which is mostly scalar coding, the CRAY X-MP is about 2.5 times faster overall than the CRAY-1.

  5. The Entropy and Complexity of Drift waves in a LAPTAG Plasma Physics Experiment

    NASA Astrophysics Data System (ADS)

    Birge-Lee, Henry; Gekelman, Walter; Pribyl, Patrick; Wise, Joe; Katz, Cami; Baker, Bob; Marmie, Ken; Thomas, Sam; Buckley-Bonnano, Samuel

    2015-11-01

    Drift waves grow from noise on a density gradient in a narrow (dia = 3 cm, L = 1.5 m) magnetized (Boz = 160G) plasma column. A two-dimensional probe drive measured fluctuations in the plasma column in a plane transverse to the background magnetic field. Correlation techniques determined that the fluctuations were that of electrostatic drift waves. The time series data was used to generate the Bandt-Pompe/Shannon entropy, H, and Jensen-Shannon complexity, CJS. C-H diagrams can be used to tell the difference between deterministic chaos, random noise and stochastic processes and simple waves, which makes it a powerful tool in nonlinear dynamics. The C-H diagram in this experiment, reveal that the combination of drift waves and other background fluctuations is a deterministically chaotic system. The PDF of the time series, the wave spectra the spatial dependence of the entropy wave complexity will be presented. LAPTAG is a university-high school alliance outreach program, which has been in existence for over 20 years. Work done at BaPSF at UCLA and supported by NSF and DOE.

  6. PREFACE: 1st European Conference on Gas Micro Flows (GasMems 2012)

    NASA Astrophysics Data System (ADS)

    Frijns, Arjan; Valougeorgis, Dimitris; Colin, Stéphane; Baldas, Lucien

    2012-05-01

    The aim of the 1st European Conference on Gas Micro Flows is to advance research in Europe and worldwide in the field of gas micro flows as well as to improve global fundamental knowledge and to enable technological applications. Gas flows in microsystems are of great importance and touch almost every industrial field (e.g. fluidic microactuators for active control of aerodynamic flows, vacuum generators for extracting biological samples, mass flow and temperature micro-sensors, pressure gauges, micro heat-exchangers for the cooling of electronic components or for chemical applications, and micro gas analyzers or separators). The main characteristic of gas microflows is their rarefaction, which for device design often requires modelling and simulation both by continuous and molecular approaches. In such flows various non-equilibrium transport phenomena appear, while the role played by the interaction between the gas and the solid device surfaces becomes essential. The proposed models of boundary conditions often need an empirical adjustment strongly dependent on the micro manufacturing technique. The 1st European Conference on Gas Micro Flows is organized under the umbrella of the recently established GASMEMS network (www.gasmems.eu/) consisting of 13 participants and six associate members. The main objectives of the network are to structure research and train researchers in the fields of micro gas dynamics, measurement techniques for gaseous flows in micro experimental setups, microstructure design and micro manufacturing with applications in lab and industry. The conference takes place on June 6-8 2012, at the Skiathos Palace Hotel, on the beautiful island of Skiathos, Greece. The conference has received funding from the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement ITN GASMEMS no. 215504. It owes its success to many people. We would like to acknowledge the support of all members of the Scientific Committee and of all

  7. PREFACE: 1st International Conference on Rheology and Modeling of Materials

    NASA Astrophysics Data System (ADS)

    Gömze, László A.

    2015-04-01

    Understanding the rheological properties of materials and their rheological behaviors during their manufacturing processes and in their applications in many cases can help to increase the efficiency and competitiveness not only of the finished goods and products but the organizations and societies also. The more scientific supported and prepared organizations develop more competitive products with better thermal, mechanical, physical, chemical and biological properties and the leading companies apply more competitive knowledge, materials, equipment and technology processes. The idea to organize in Hungary the 1st International Conference on Rheology and Modeling of Materials we have received from prospective scientists, physicists, chemists, mathematicians and engineers from Asia, Europe, North and South America including India, Korea, Russia, Turkey, Estonia, France, Italy, United Kingdom, Chile, Mexico and USA. The goals of ic-rmm1 the 1st International Conference on Rheology and Modeling of Materials are the following: • Promote new methods and results of scientific research in the fields of modeling and measurements of rheological properties and behavior of materials under processing and applications. • Change information between the theoretical and applied sciences as well as technical and technological implantations. • Promote the communication between the scientists of different disciplines, nations, countries and continents. The international conference ic-rmm1 provides a platform among the leading international scientists, researchers, PhD students and engineers for discussing recent achievements in measurement, modeling and application of rheology in materials technology and materials science of liquids, melts, solids, crystals and amorphous structures. Among the major fields of interest are the influences of material structures, mechanical stresses temperature and deformation speeds on rheological and physical properties, phase transformation of

  8. Particle Control and Plasma Performance in the Lithium Tokamak Experiment (LTX)

    SciTech Connect

    Richard Majeski, et. al.

    2013-02-21

    The Lithium Tokamak eXperiment (LTX) is a small, low aspect ratio tokamak, which is fitted with a stainless steel-clad copper liner, conformal to the last closed flux surface. The liner can be heated to 350{degree}C. Several gas fueling systems, including supersonic gas injection, and molecular cluster injection have been studied, and produce fueling efficiencies up to 35%. Discharges are strongly affected by wall conditioning. Discharges without lithium wall coatings are limited to plasma currents of order 10 kA, and discharge durations of order 5 msec. With solid lithium coatings discharge currents exceed 70 kA, and discharge durations exceed 30 msec. Heating the lithium wall coating, however, results in a prompt degradation of the discharge, at the melting point of lithium. These results suggest that the simplest approach to implementing liquid lithium walls in a tokamak - thin, evaporated, liquefied coatings of lithium - does not produce an adequately clean surface.

  9. Characterization of scintillators for lost alpha diagnostics on burning plasma experiments

    SciTech Connect

    Nishiura, M.; Kubo, N.; Hirouchi, T.; Ido, T.; Nagasaka, T.; Mutoh, T.; Matsuyama, S.; Isobe, M.; Okamoto, A.; Shinto, K.; Kitajima, S.; Sasao, M.; Nakatsuka, M.; Fujioka, K.

    2006-10-15

    The characteristics of light output by ion beam irradiations under high ion fluxes have been measured for three kinds of scintillators: ZnS:Ag deposited on the glass plate, Y{sub 3}Al{sub 5}O{sub 12}:Ce powder stiffened with a binder, and Y{sub 3}Al{sub 5}O{sub 12}:Ce ceramics sintered at high temperature. The ion beam flux in the range from 10{sup 12} to 10{sup 13} ions/(cm{sup 2} s) is irradiated to simulate the burning plasma experiments. The decrease of light output has been observed by long time ion irradiation. The deterioration of ZnS:Ag deposited scintillator is most serious. The deterioration has been improved for the scintillators of Y{sub 3}Al{sub 5}O{sub 12}:Ce with a binder and that sintered. Their applications to ITER lost alpha diagnostics are discussed.

  10. Determination of the levitation limits of dust particles within the sheath in complex plasma experiments

    SciTech Connect

    Douglass, Angela; Land, Victor; Qiao Ke; Matthews, Lorin; Hyde, Truell

    2012-01-15

    Experiments are performed in which dust particles are levitated at varying heights above the powered electrode in a radio frequency plasma discharge by changing the discharge power. The trajectories of particles dropped from the top of the discharge chamber are used to reconstruct the vertical electric force acting on the particles. The resulting data, together with the results from a self-consistent fluid model, are used to determine the lower levitation limit for dust particles in the discharge and the approximate height above the lower electrode where quasineutrality is attained, locating the sheath edge. These results are then compared with current sheath models. It is also shown that particles levitated within a few electron Debye lengths of the sheath edge are located outside the linearly increasing portion of the electric field.

  11. Colliding pulse injection experiments in non-collinear geometryfor controlled laser plasma wakefield acceleration of electrons

    SciTech Connect

    Toth, Carl B.; Esarey, Eric H.; Geddes, Cameron G.R.; Leemans,Wim P.; Nakamura, Kei; Panasenko, Dmitriy; Schroeder, Carl B.; Bruhwiler,D.; Cary, J.R.

    2007-06-25

    An optical injection scheme for a laser-plasma basedaccelerator which employs a non-collinear counter-propagating laser beamto push background electrons in the focusing and acceleration phase viaponderomotive beat with the trailing part of the wakefield driver pulseis discussed. Preliminary experiments were performed using a drive beamof a_0 = 2.6 and colliding beam of a_1 = 0.8 both focused on the middleof a 200 mu m slit jet backed with 20 bar, which provided ~; 260 mu mlong gas plume. The enhancement in the total charge by the collidingpulse was observed with sharp dependence on the delay time of thecolliding beam. Enhancement of the neutron yield was also measured, whichsuggests a generation of electrons above 10 MeV.

  12. Improvements to Convergent Cylindrical Plasma Mix Experiments using Laser Direct Drive

    NASA Astrophysics Data System (ADS)

    Barnes, Cris W.; Batha, Steven H.; Lanier, N. E.; Magelssen, G. R.; Murphy, T. J.; Scott, J. M.; Dunne, A. M.; Parker, K. W.; Rothman, Stephen; Youngs, David

    2001-10-01

    Experiments studying mix in a compressible, convergent, miscible, plasma system are being conducted on the OMEGA Laser. Thin-walled polystyrene cylinders 2.25-mm long and 0.86 mm inner diameter with foam inside are directly illuminated with 351-nm wavelength light from 50 laser beams in a 1-ns square laser pulse. The turbulence driven by the Richtmyer-Meshkov instability by shock passage across a density discontinuity mixes marker material that is radiographically opaque. Initial work using a high-density, high-opacity marker layer of gold between the plastic ablator and foam clearly demonstrated significant measurable mix width. However, the high opacity of the gold prevented determination of a density profile in the mix region, and it was also overly sensitive to hydrodynamic effects at the end of the marker layer. Use of lower opacity marker material will be described and its impact on end effects and the measurements of mix density profile described.

  13. Impact of Modified Conductivity Models on Numerical Simulation of Strongly Coupled Plasma Experiments

    NASA Astrophysics Data System (ADS)

    Munson, Carter P.; Benage, John F.; Tierney, Thomas E.; Workman, Jonathan

    2000-10-01

    1-D MHD codes have routinely been employed in the preliminary design of pulsed power hydrodynamics and strongly coupled plasma experiments at Los Alamos National Laboratory. Recent experimental work by Benage, et. al.(Benage, J.F., Shanahan, W.R., and Murillo, M.S., Physical Review Letters), 83, no. 15, pg. 2953, (1999) however, has shown that the established theories used to generate the resistivity tables previously employed in these numerical codes are inadequate in relevant portions of the density and temperature parameter regimes. The best theoretical match to the resistivity data of Benage is provided by a density functional model of Perrot and Dharma-Wardana. Newly available conductivity tables for Aluminum(provided by Mike Desjarlais and Steve Rosenthal of Sandia National Laboratory) are being used to re-evaluate previously modeled experimental configurations. Details of the impact of the various resistivity models on prediction of experimental configurations will be presented.

  14. Observation of quasi-coherent edge fluctuations in Ohmic plasmas on National Spherical Torus Experiment

    NASA Astrophysics Data System (ADS)

    Banerjee, Santanu; Diallo, A.; Zweben, S. J.

    2016-04-01

    A quasi-coherent edge density mode with frequency fmode ˜ 40 kHz is observed in Ohmic plasmas in National Spherical Torus Experiment using the gas puff imaging diagnostic. This mode is located predominantly just inside the separatrix, with a maximum fluctuation amplitude significantly higher than that of the broadband turbulence in the same frequency range. The quasi-coherent mode has a poloidal wavelength λpol ˜ 16 cm and a poloidal phase velocity of Vpol ˜ 4.9 ± 0.3 km s-1 in the electron diamagnetic direction, which are similar to the characteristics expected from a linear drift-wave-like mode in the edge. This is the first observation of a quasi-coherent edge mode in an Ohmic diverted tokamak, and so may be useful for validating tokamak edge turbulence codes.

  15. Design of the EO-1 Pulsed Plasma Thruster Attitude Control Experiment

    NASA Technical Reports Server (NTRS)

    Zakrzwski, Charles; Sanneman, Paul; Hunt, Teresa; Blackman, Kathie; Bauer, Frank H. (Technical Monitor)

    2001-01-01

    The Pulsed Plasma Thruster (PPT) Experiment on the Earth Observing 1 (EO-1) spacecraft has been designed to demonstrate the capability of a new generation PPT to perform spacecraft attitude control. The PPT is a small, self-contained pulsed electromagnetic Propulsion system capable of delivering high specific impulse (900-1200 s), very small impulse bits (10-1000 micro N-s) at low average power (less than 1 to 100 W). EO-1 has a single PPT that can produce torque in either the positive or negative pitch direction. For the PPT in-flight experiment, the pitch reaction wheel will be replaced by the PPT during nominal EO-1 nadir pointing. A PPT specific proportional-integral-derivative (PID) control algorithm was developed for the experiment. High fidelity simulations of the spacecraft attitude control capability using the PPT were conducted. The simulations, which showed PPT control performance within acceptable mission limits, will be used as the benchmark for on-orbit performance. The flight validation will demonstrate the ability of the PPT to provide precision pointing resolution. response and stability as an attitude control actuator.

  16. Energetic particle physics in fusion research in preparation for burning plasma experiments

    NASA Astrophysics Data System (ADS)

    Gorelenkov, N. N.; Pinches, S. D.; Toi, K.

    2014-12-01

    The area of energetic particle (EP) physics in fusion research has been actively and extensively researched in recent decades. The progress achieved in advancing and understanding EP physics has been substantial since the last comprehensive review on this topic by Heidbrink and Sadler (1994 Nucl. Fusion 34 535). That review coincided with the start of deuterium-tritium (DT) experiments on the Tokamak Fusion Test Reactor (TFTR) and full scale fusion alphas physics studies. Fusion research in recent years has been influenced by EP physics in many ways including the limitations imposed by the ‘sea’ of Alfvén eigenmodes (AEs), in particular by the toroidicity-induced AE (TAE) modes and reversed shear AEs (RSAEs). In the present paper we attempt a broad review of the progress that has been made in EP physics in tokamaks and spherical tori since the first DT experiments on TFTR and JET (Joint European Torus), including stellarator/helical devices. Introductory discussions on the basic ingredients of EP physics, i.e., particle orbits in STs, fundamental diagnostic techniques of EPs and instabilities, wave particle resonances and others, are given to help understanding of the advanced topics of EP physics. At the end we cover important and interesting physics issues related to the burning plasma experiments such as ITER (International Thermonuclear Experimental Reactor).

  17. Energetic Particle Physics In Fusion Research In Preparation For Burning Plasma Experiments

    SciTech Connect

    Gorelenkov, Nikolai N

    2013-06-01

    The area of energetic particle (EP) physics of fusion research has been actively and extensively researched in recent decades. The progress achieved in advancing and understanding EP physics has been substantial since the last comprehensive review on this topic by W.W. Heidbrink and G.J. Sadler [1]. That review coincided with the start of deuterium-tritium (DT) experiments on Tokamak Fusion Test reactor (TFTR) and full scale fusion alphas physics studies. Fusion research in recent years has been influenced by EP physics in many ways including the limitations imposed by the "sea" of Alfven eigenmodes (AE) in particular by the toroidicityinduced AEs (TAE) modes and reversed shear Alfven (RSAE). In present paper we attempt a broad review of EP physics progress in tokamaks and spherical tori since the first DT experiments on TFTR and JET (Joint European Torus) including helical/stellarator devices. Introductory discussions on basic ingredients of EP physics, i.e. particle orbits in STs, fundamental diagnostic techniques of EPs and instabilities, wave particle resonances and others are given to help understanding the advanced topics of EP physics. At the end we cover important and interesting physics issues toward the burning plasma experiments such as ITER (International Thermonuclear Experimental Reactor).

  18. Stark broadening of hydrogen lines in dense plasmas: analysis of recent experiments.

    PubMed

    Alexiou, S

    2005-06-01

    In recent years experiments conducted by a number of different groups on line broadening of hydrogen lines, mainly H(alpha) on dense plasmas of densities larger than or equal to 10(18) e/cm3 have claimed significant differences from the predictions of the standard theory. At these high densities the standard theory predictions depend on some cutoffs, necessary to preserve unitarity, the long range approximation and to ensure the validity of a semiclassical picture. Furthermore, a new, supposedly "advanced" theory based on a number of incorrect assumptions and/or approximations with extra exotic effects has claimed good agreement with these experiments. In this work we produce benchmark simulation calculations for these data to identify relevant and not relevant physics for the parameters of these experiments. In this way, we evaluate claims of electron-ion coupling, ion dynamics, electron vs ion broadening, nonimpact effects, and nonperturbative effects. At least one data set is seen to be dubious, in agreement with previous analyses. PMID:16089876

  19. Four-color laser irradiation system for laser-plasma interaction experiments

    SciTech Connect

    Pennington, D.M.; Henesian, M.A.; Wilcox, R.B.

    1996-06-01

    Since 1986, optical smoothing of the laser irradiance on targets for Inertial Confinement Fusion (ICF) has gained increasing attention. Optical smoothing can significantly reduce wavefront aberrations that produce nonuniformities in the energy distribution of the focal spot. Hot spots in the laser irradiance can induce local self focusing of the light, producing filamentation of the plasma. Filamentation can have detrimental consequences on the hydrodynamics of an ICF plasma, and can affect the growth of parametric instabilities, as well as add to the complexity of the study of such instabilities as stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS). As experiments approach and exceed breakeven (i.e., where driver energy = fusion yield), the likelihood of significant excitation of these processes increases. As a result, the authors are including a scheme for implementing optical-beam smoothing for target experiments in the baseline design for the proposed next-generation ICF facility--the National Ignition Facility (NIF). To verify the efficacy of this design for the suppression of parametric instabilites in NIF-like indirect-drive targets, the authors successfully modified a Nova beamline to simulate the proposed NIF conditions. In this article, they discuss the laser science associated with a four-color target campaign on Nova to test the effect of f-number (ratio of focal length to beam diameter) and temporal smoothing on the scaling of SBS with a four-segment interaction beam using NIF-like parameters. The results of the target series associated with the four-color configuration are discussed elsewhere.

  20. Study of Thermonuclear Alfven Instabilities in Next Step Burning Plasma Experiments

    SciTech Connect

    N.N. Gorelenkov; H.L. Berk; R. Budny; C.Z. Cheng; G.-Y. Fu; W.W. Heidbrink; G. Kramer; D. Meade; and R. Nazikian

    2002-07-02

    A study is presented for the stability of alpha-particle driven shear Alfven Eigenmodes (AE) for the normal parameters of the three major burning plasma proposals, ITER (International Thermonuclear Experimental Reactor), FIRE (Fusion Ignition Research Experiment), and IGNITOR (Ignited Torus). A study of the JET (Joint European Torus) plasma, where fusion alphas were generated in tritium experiments, is also included to attempt experimental validation of the numerical predictions. An analytic assessment of Toroidal AE (TAE) stability is first presented, where the alpha particle beta due to the fusion reaction rate and electron drag is simply and accurately estimated in 7-20 keV plasma temperature regime. In this assessment the hot particle drive is balanced against ion-Landau damping of the background deuterons and electron collision effects and stability boundaries are determined. Then two numerical studies of AE instability are presented. In one the High-n stability code HINST is used . This code is capable of predicting instabilities of low and moderately high frequency Alfven modes. HINST computes the non-perturbative solution of the Alfven eigenmodes including effects of ion finite Larmor radius, orbit width, trapped electrons etc. The stability calculations are repeated using the global code NOVAK. We show that for these tokamaks the spectrum of the least stable AE modes are TAE that appear at medium-/high-n numbers. In HINST TAEs are locally unstable due to the alphas pressure gradient in all the devices under the consideration except IGNITOR. However, NOVAK calculations show that the global mode structure enhances the damping mechanisms and produces stability in all configurations considered here. A serious question remains whether the perturbation theory used in NOVAK overestimates the stability predictions, so that it is premature to conclude that the nominal operation of all three proposals are stable to AEs. In addition NBI ions produce a strong

  1. Calibrated simulations of Z opacity experiments that reproduce the experimentally measured plasma conditions

    DOE PAGES

    Nagayama, T.; Bailey, J. E.; Loisel, G.; Rochau, G. A.; MacFarlane, J. J.; Golovkin, I.

    2016-02-05

    Recently, frequency-resolved iron opacity measurements at electron temperatures of 170–200 eV and electron densities of (0.7 – 4.0) × 1022 cm–3 revealed a 30–400% disagreement with the calculated opacities [J. E. Bailey et al., Nature (London) 517, 56 (2015)]. The discrepancies have a high impact on astrophysics, atomic physics, and high-energy density physics, and it is important to verify our understanding of the experimental platform with simulations. Reliable simulations are challenging because the temporal and spatial evolution of the source radiation and of the sample plasma are both complex and incompletely diagnosed. In this article, we describe simulations that reproducemore » the measured temperature and density in recent iron opacity experiments performed at the Sandia National Laboratories Z facility. The time-dependent spectral irradiance at the sample is estimated using the measured time- and space-dependent source radiation distribution, in situ source-to-sample distance measurements, and a three-dimensional (3D) view-factor code. The inferred spectral irradiance is used to drive 1D sample radiation hydrodynamics simulations. The images recorded by slit-imaged space-resolved spectrometers are modeled by solving radiation transport of the source radiation through the sample. We find that the same drive radiation time history successfully reproduces the measured plasma conditions for eight different opacity experiments. These results provide a quantitative physical explanation for the observed dependence of both temperature and density on the sample configuration. Simulated spectral images for the experiments without the FeMg sample show quantitative agreement with the measured spectral images. The agreement in spectral profile, spatial profile, and brightness provides further confidence in our understanding of the backlight-radiation time history and image formation. Furthermore, these simulations bridge the static-uniform picture of the

  2. Calibrated simulations of Z opacity experiments that reproduce the experimentally measured plasma conditions

    NASA Astrophysics Data System (ADS)

    Nagayama, T.; Bailey, J. E.; Loisel, G.; Rochau, G. A.; MacFarlane, J. J.; Golovkin, I.

    2016-02-01

    Recently, frequency-resolved iron opacity measurements at electron temperatures of 170-200 eV and electron densities of (0.7 - 4.0 )× 1022cm-3 revealed a 30 - 400 % disagreement with the calculated opacities [J. E. Bailey et al., Nature (London) 517, 56 (2015), 10.1038/nature14048]. The discrepancies have a high impact on astrophysics, atomic physics, and high-energy density physics, and it is important to verify our understanding of the experimental platform with simulations. Reliable simulations are challenging because the temporal and spatial evolution of the source radiation and of the sample plasma are both complex and incompletely diagnosed. In this article, we describe simulations that reproduce the measured temperature and density in recent iron opacity experiments performed at the Sandia National Laboratories Z facility. The time-dependent spectral irradiance at the sample is estimated using the measured time- and space-dependent source radiation distribution, in situ source-to-sample distance measurements, and a three-dimensional (3D) view-factor code. The inferred spectral irradiance is used to drive 1D sample radiation hydrodynamics simulations. The images recorded by slit-imaged space-resolved spectrometers are modeled by solving radiation transport of the source radiation through the sample. We find that the same drive radiation time history successfully reproduces the measured plasma conditions for eight different opacity experiments. These results provide a quantitative physical explanation for the observed dependence of both temperature and density on the sample configuration. Simulated spectral images for the experiments without the FeMg sample show quantitative agreement with the measured spectral images. The agreement in spectral profile, spatial profile, and brightness provides further confidence in our understanding of the backlight-radiation time history and image formation. These simulations bridge the static-uniform picture of the data

  3. Calibrated simulations of Z opacity experiments that reproduce the experimentally measured plasma conditions.

    PubMed

    Nagayama, T; Bailey, J E; Loisel, G; Rochau, G A; MacFarlane, J J; Golovkin, I

    2016-02-01

    Recently, frequency-resolved iron opacity measurements at electron temperatures of 170-200 eV and electron densities of (0.7-4.0)×10(22)cm(-3) revealed a 30-400% disagreement with the calculated opacities [J. E. Bailey et al., Nature (London) 517, 56 (2015)]. The discrepancies have a high impact on astrophysics, atomic physics, and high-energy density physics, and it is important to verify our understanding of the experimental platform with simulations. Reliable simulations are challenging because the temporal and spatial evolution of the source radiation and of the sample plasma are both complex and incompletely diagnosed. In this article, we describe simulations that reproduce the measured temperature and density in recent iron opacity experiments performed at the Sandia National Laboratories Z facility. The time-dependent spectral irradiance at the sample is estimated using the measured time- and space-dependent source radiation distribution, in situ source-to-sample distance measurements, and a three-dimensional (3D) view-factor code. The inferred spectral irradiance is used to drive 1D sample radiation hydrodynamics simulations. The images recorded by slit-imaged space-resolved spectrometers are modeled by solving radiation transport of the source radiation through the sample. We find that the same drive radiation time history successfully reproduces the measured plasma conditions for eight different opacity experiments. These results provide a quantitative physical explanation for the observed dependence of both temperature and density on the sample configuration. Simulated spectral images for the experiments without the FeMg sample show quantitative agreement with the measured spectral images. The agreement in spectral profile, spatial profile, and brightness provides further confidence in our understanding of the backlight-radiation time history and image formation. These simulations bridge the static-uniform picture of the data interpretation and the

  4. Identifying 1st instar larvae for three forensically important blowfly species using "fingerprint" cuticular hydrocarbon analysis.

    PubMed

    Moore, Hannah E; Adam, Craig D; Drijfhout, Falko P

    2014-07-01

    Calliphoridae are known to be the most forensically important insects when it comes to establishing the minimum post mortem interval (PMImin) in criminal investigations. The first step in calculating the PMImin is to identify the larvae present to species level. Accurate identification which is conventionally carried out by morphological analysis is crucial because different insects have different life stage timings. Rapid identification in the immature larvae stages would drastically cut time in criminal investigations as it would eliminate the need to rear larvae to adult flies to determine the species. Cuticular hydrocarbon analysis on 1st instar larvae has been applied to three forensically important blowflies; Lucilia sericata, Calliphora vicina and Calliphora vomitoria, using gas chromatography-mass spectrometry (GC-MS) and principal component analysis (PCA). The results show that each species holds a distinct "fingerprint" hydrocarbon profile, allowing for accurate identification to be established in 1-day old larvae, when it can be challenging to apply morphological criteria. Consequently, this GC-MS based technique could accelerate and strengthen the identification process, not only for forensically important species, but also for other entomological samples which are hard to identify using morphological features.

  5. The relation between 1st grade grey matter volume and 2nd grade math competence.

    PubMed

    Price, Gavin R; Wilkey, Eric D; Yeo, Darren J; Cutting, Laurie E

    2016-01-01

    Mathematical and numerical competence is a critical foundation for individual success in modern society yet the neurobiological sources of individual differences in math competence are poorly understood. Neuroimaging research over the last decade suggests that neural mechanisms in the parietal lobe, particularly the intraparietal sulcus (IPS) are structurally aberrant in individuals with mathematical learning disabilities. However, whether those same brain regions underlie individual differences in math performance across the full range of math abilities is unknown. Furthermore, previous studies have been exclusively cross-sectional, making it unclear whether variations in the structure of the IPS are caused by or consequences of the development of math skills. The present study investigates the relation between grey matter volume across the whole brain and math competence longitudinally in a representative sample of 50 elementary school children. Results show that grey matter volume in the left IPS at the end of 1st grade relates to math competence a year later at the end of 2nd grade. Grey matter volume in this region did not change over that year, and was still correlated with math competence at the end of 2nd grade. These findings support the hypothesis that the IPS and its associated functions represent a critical foundation for the acquisition of mathematical competence. PMID:26334946

  6. The relation between 1st grade grey matter volume and 2nd grade math competence.

    PubMed

    Price, Gavin R; Wilkey, Eric D; Yeo, Darren J; Cutting, Laurie E

    2016-01-01

    Mathematical and numerical competence is a critical foundation for individual success in modern society yet the neurobiological sources of individual differences in math competence are poorly understood. Neuroimaging research over the last decade suggests that neural mechanisms in the parietal lobe, particularly the intraparietal sulcus (IPS) are structurally aberrant in individuals with mathematical learning disabilities. However, whether those same brain regions underlie individual differences in math performance across the full range of math abilities is unknown. Furthermore, previous studies have been exclusively cross-sectional, making it unclear whether variations in the structure of the IPS are caused by or consequences of the development of math skills. The present study investigates the relation between grey matter volume across the whole brain and math competence longitudinally in a representative sample of 50 elementary school children. Results show that grey matter volume in the left IPS at the end of 1st grade relates to math competence a year later at the end of 2nd grade. Grey matter volume in this region did not change over that year, and was still correlated with math competence at the end of 2nd grade. These findings support the hypothesis that the IPS and its associated functions represent a critical foundation for the acquisition of mathematical competence.

  7. The U.S. Naval Observatory Robotic Astrometric Telescope 1st Catalog (URAT1)

    NASA Astrophysics Data System (ADS)

    Zacharias, Norbert; Finch, Charlie T.; Subasavage, John P.; Tilleman, Trudy; DiVittorio, Mike; Harris, Hugh C.; Rafferty, Ted; Wieder, Gary; Eric Ferguson, Chris Kilian, Albert Rhodes, Mike Schultheis

    2015-01-01

    The 1st USNO Robotic Astrometric Telescope Catalog (URAT1) is about tobe released. It contains accurate positions (typically 10 to 30 mas std.error) of 220 million stars, mainly on the northern hemisphere. Propermotions were obtained for 85% of these stars utilizing the 2MASS as 1stepoch. URAT1 is supplemented by 2MASS and APASS photometry. The URAT1catalog was derived from 2 years of operations (April 2012 to April 2014)of the USNO "redlens" astrograph with its 474 Mpx 4-shooter camera at theNaval Observatory Flagstaff Station (NOFS) in a joint effort betweenUSNO's Astrometry Department and NOFS. Due to a combination of longexposures and short exposures with objective grating, URAT1 observationscover the large 3 to 18.5 magnitude range in a single 680-750 nm bandpass.The catalog properties are presented together with a brief summary ofobservations and reductions methods. URAT1 has on average about 4-timesthe number of stars per square degree and is 4-times more accurate thanUCAC4. URAT1 will serve as the currently most accurate astrometric anddeep photometric optical reference star catalog until the delivery ofthe Gaia catalog.

  8. 1st paleomagnetic investigation of Nubia Sandstone at Kalabsha, south Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Mostafa, R.; Khashaba, A.; El-Hemaly, I. A.; Takla, E. M.; Abdel Aal, E.; Odah, H.

    2016-06-01

    Two profiles have been sampled from the Nubia Sandstone at Aswan, south Western Desert: the 1st profile has been taken from Abu Aggag Formation and the 2nd one was from Sabaya Formation (23.25 °N, 32.75 °E). 136 oriented cores (from 9 sites) have been sampled. Abu Aggag Formation is of Late Cretaceous (Turonian) and Sabaya Formation is of early Cretaceous (Albian-Cenomanian). The studied rocks are subjected to rock magnetic measurements as well as demagnetization treatment. It has been found that hematite is the main magnetic mineral in both formations. Four profile sections from Abu Aggag Formation, yielded a magnetic component with D = 352.7°, I = 36.6° with α95 = 5.2° and the corresponding pole lies at Lat. = 82.8 °N and Long. = 283.1 °E. Five profile sections from Sabaya Formation, yielded a magnetic component with D = 348.6°, I = 33.3° with α95 = 5.8° and the corresponding pole lies at Lat. = 78.3 °N and Long. = 280.4 °E. The obtained paleopole for the two formations lies at Lat. = 80.5 °N and Long. = 281.7 °E. The obtaind magnetic components are considered primary and the corresponding paleopole reflects the age of Nubia Sandstone when compared with the previously obtained Cretaceous poles for Egypt.

  9. Wind-US Results for the AIAA 1st Propulsion Aerodynamics Workshop

    NASA Technical Reports Server (NTRS)

    Yoder, Dennis; Dippold, Vance, III; Georgiadis, Nicholas

    2012-01-01

    This presentation contains Wind-US results presented at the 1st Propulsion Aerodynamics Workshop. The The workshop was organized by the American Institute of Aeronautics and Astronautics, Air Breathing Propulsion Propulsion Systems Integration Technical Committee with the purpose of assessing the accuracy of computational computational fluid dynamics for air breathing propulsion applications. Attendees included representatives from representatives from government, industry, academia, and commercial software companies. Participants were were encouraged to explore and discuss all aspects of the simulation process including the effects of mesh type and mesh type and refinement, solver numerical schemes, and turbulence modeling. The first set of challenge cases involved computing the thrust and discharge coefficients for a series of convergent convergent nozzles for a range of nozzle pressure ratios between 1.4 and 7.0. These configurations included a included a reference axisymmetric nozzle as well as 15deg , 25deg , and 40deg conical nozzles. Participants were also asked also asked to examine the plume shock structure for two cases where the 25deg conical nozzle was bifurcated by a bifurcated by a solid plate. The final test case was a serpentine inlet diffuser with an outlet to inlet area ratio of 1.52 ratio of 1.52 and an offset of 1.34 times the inlet diameter. Boundary layer profiles, wall static pressure, and total and total pressure at downstream rake locations were examined.

  10. PROPAGATION AND EVOLUTION OF THE JUNE 1st 2008 CME IN THE INTERPLANETARY MEDIUM

    NASA Astrophysics Data System (ADS)

    Nieves-Chinchilla, T.; Lamb, D. A.; Davila, J. M.; Vinas, A. F.; Moestl, C.; Hidalgo, M. A.; Farrugia, C. J.; Malandraki, O.; Dresing, N.; Gómez-Herrero, R.

    2009-12-01

    In this work we present a study of the coronal mass ejection (CME) of June 1st of 2008 in the interplanetary medium. This event has been extensively studied by others because of its favorable geometry and the possible consequences of its peculiar initiation for space weather forecasting. We show an analysis of the evolution of the CME in the interplanetary medium in order to shed some light on the propagation mechanism of the ICME. We have determined the typical shock associated characteristics of the ICME in order to understand the propagation properties. Using two different non force-free models of the magnetic cloud allows us to incorporate expansion of the cloud. We use in-situ measurements from STEREO B/IMPACT to characterize the ICME. In addition, we use images from STEREO A/SECCHI-HI to analyze the propagation and visual evolution of the associated flux rope in the interplanetary medium. We compare and contrast these observations with the results of the analytical models.

  11. 78 FR 47698 - Notice to all Interested Parties of the Termination of the Receivership of 10183, 1st American...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-06

    ... From the Federal Register Online via the Government Publishing Office FEDERAL DEPOSIT INSURANCE CORPORATION Notice to all Interested Parties of the Termination of the Receivership of 10183, 1st American State Bank of Minnesota Hancock, MN Notice is hereby given that the Federal Deposit...

  12. 78 FR 7781 - Filing Dates for the South Carolina Special Elections in the 1st Congressional District

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-04

    ... From the Federal Register Online via the Government Publishing Office FEDERAL ELECTION COMMISSION Filing Dates for the South Carolina Special Elections in the 1st Congressional District AGENCY: Federal Election Commission. ACTION: Notice of filing dates for special elections. SUMMARY: South Carolina...

  13. Bills to Increase Employment Opportunities through the Youth Conservation Corps and Other Means, 95th Congress, 1st Session.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC.

    This packet contains nine Senate bills and eight House bills from the 95th Congress, 1st session, all dealing with various means of increasing employment opportunities. Most of the bills deal with the creation of new jobs or with programs for job training, counseling, or placement. Seven of the bills constitute amendments to the Youth Conservation…

  14. Jordanian Kindergarten and 1st-Grade Teachers' Beliefs about Child-Based Dimensions of School Readiness

    ERIC Educational Resources Information Center

    Fayez, Merfat; Ahmad, Jamal Fathi; Oliemat, Enass

    2016-01-01

    The purpose of this study was to explore the beliefs of Jordanian kindergarten and 1st-grade teachers regarding six child-based dimensions of school readiness: academic knowledge, basic thinking skills, socioemotional maturity, physical well-being and motor development, self-discipline, and communication skills. Questionnaires were used to collect…

  15. Maternal Sleep-Related Cognitions and Infant Sleep: A Longitudinal Study from Pregnancy through the 1st Year

    ERIC Educational Resources Information Center

    Tikotzky, Liat; Sadeh, Avi

    2009-01-01

    Infant sleep is a major source of concern for many parents. The aims of this longitudinal study were to assess: (a) the development of sleep patterns among infants, (b) the development of maternal cognitions regarding infant sleep, and (c) the relations between these domains during the 1st year of life. Eighty-five mothers were recruited during…

  16. Addressing the Effects of Reciprocal Teaching on the Receptive and Expressive Vocabulary of 1st-Grade Students

    ERIC Educational Resources Information Center

    Mandel, Eliana; Osana, Helena P.; Venkatesh, Vivek

    2013-01-01

    This study evaluated the effects of Adapted Reciprocal Teaching (ART) on the receptive and expressive flight-word vocabulary of 1st-grade students. During ART, classroom interactions produced narrative contexts within which students assumed responsibility for applying new flight words in personally meaningful ways. Students in the control group…

  17. Active Measurement of Mercury's Plasma experiment: a part of the Plasma Wave Investigation consortium aboard the BepiColombo Mercury Magnetospheric Orbiter

    NASA Astrophysics Data System (ADS)

    Trotignon, Jean Gabriel; Trotignon, Jean Gabriel; Lagoutte, Dominique; Kasaba, Yasumasa; Kojima, Hiro; Blomberg, Lars; Lebreton, Jean-Pierre

    The Active Measurement of Mercury's Plasma experiment, AM2 P, is designed to measure the thermal electron density and temperature in the environment of planet Mercury from the solar wind down to the inner magnetosphere. Detailed analyses of the returned data should also give more information on the electron distribution function itself. AM2 P as part of the Plasma Wave Investigation consortium, PWI, shall then contribute to the study of the intricate and poorly known interaction between the solar wind and the Mercury's magnetosphere, exosphere, and surface. AM2 P shall indeed give another insight into the thermal coupling between neutral and charged particles, the characterization of the spectral distribution of natural waves, the detection of plasma boundaries, and the identification of the plasma regimes inside the Hermean magnetosphere. The AM2 P basic mode is to measure the self-impedance of the MEFISTO (Mercury Electric Field In Situ TOol) double-sphere antenna in a frequency range comprising the plasma frequency which is expected to lie in the various regions encountered by the Mercury Magnetospheric Orbiter, MMO. In this mode, different operations are possible, giving complementary plasma parameter information, mainly in the vicinity of the plasma resonance: normal dipole, monopole, and mutual impedance, according to the antenna elements that are used for the transmitting and receiving functions. In the secondary MEFISTO double-wire antenna mode, the external shield of the wire-boom is used as a 2 x 15 m long dipole antenna. As the dependence upon plasma parameters of the double-wire antenna impedance differs significantly from the double-sphere one, both modes may be of great benefit for achieving reliable and complementary plasma diagnoses. This is actually very useful in the Mercury's dilute media. As a bonus, AM2 P will contribute to the onboard calibrations of the WPT wire electric-antenna and the SC-DB and SC-LF search coils (calibration signal

  18. Investigating plasma viscosity with fast framing photography in the ZaP-HD Flow Z-Pinch experiment

    NASA Astrophysics Data System (ADS)

    Weed, Jonathan Robert

    The ZaP-HD Flow Z-Pinch experiment investigates the stabilizing effect of sheared axial flows while scaling toward a high-energy-density laboratory plasma (HEDLP > 100 GPa). Stabilizing flows may persist until viscous forces dissipate a sheared flow profile. Plasma viscosity is investigated by measuring scale lengths in turbulence intentionally introduced in the plasma flow. A boron nitride turbulence-tripping probe excites small scale length turbulence in the plasma, and fast framing optical cameras are used to study time-evolved turbulent structures and viscous dissipation. A Hadland Imacon 790 fast framing camera is modified for digital image capture, but features insufficient resolution to study turbulent structures. A Shimadzu HPV-X camera captures the evolution of turbulent structures with great spatial and temporal resolution, but is unable to resolve the anticipated Kolmogorov scale in ZaP-HD as predicted by a simplified pinch model.

  19. Development of a Multi-GeV spectrometer for laser-plasma experiment at FLAME

    NASA Astrophysics Data System (ADS)

    Valente, P.; Anelli, F.; Bacci, A.; Batani, D.; Bellaveglia, M.; Benocci, R.; Benedetti, C.; Cacciotti, L.; Cecchetti, C. A.; Clozza, A.; Cultrera, L.; Di Pirro, G.; Drenska, N.; Faccini, R.; Ferrario, M.; Filippetto, D.; Fioravanti, S.; Gallo, A.; Gamucci, A.; Gatti, G.; Ghigo, A.; Giulietti, A.; Giulietti, D.; Gizzi, L. A.; Koester, P.; Labate, L.; Levato, T.; Lollo, V.; Londrillo, P.; Martellotti, S.; Pace, E.; Pathak, N.; Rossi, A.; Tani, F.; Serafini, L.; Turchetti, G.; Vaccarezza, C.

    2011-10-01

    The advance in laser-plasma acceleration techniques pushes the regime of the resulting accelerated particles to higher energies and intensities. In particular, the upcoming experiments with the 250 TW laser at the FLAME facility of the INFN Laboratori Nazionali di Frascati, will enter the GeV regime with more than 100 pC of electrons. At the current status of understanding of the acceleration mechanism, relatively large angular and energy spreads are expected. There is therefore the need for developing a device capable to measure the energy of electrons over three orders of magnitude (few MeV to few GeV), with still unknown angular divergences. Within the PlasmonX experiment at FLAME, a spectrometer is being constructed to perform these measurements. It is made of an electro-magnet and a screen made of scintillating fibers for the measurement of the trajectories of the particles. The large range of operation, the huge number of particles and the need to focus the divergence, present challenges in the design and construction of such a device. We present the design considerations for this spectrometer that lead to the use of scintillating fibers, multichannel photo-multipliers and a multiplexing electronics, a combination which is innovative in the field. We also present the experimental results obtained with a high intensity electron beam performed on a prototype at the LNF beam test facility.

  20. Using xRage to Model Heat Flow for Experiments to Measure Opacities in HED Plasmas

    NASA Astrophysics Data System (ADS)

    Elgin, L.; Vandervort, R.; Keiter, P.; Drake, R. P.; Mussack, K.; Orban, C.

    2015-11-01

    We are developing a NIF proposal to measure opacities of C, N and O at temperatures and densities relevant to the base of the solar convection zone. Our proposed experiments would provide the first opacity measurements for these elements within this HED regime. A critical feature of our experimental platform is a super-sonic radiation front propagating within the targets. Under these conditions, density remains constant across the radiation front for a couple nanoseconds, enabling a window during which the opacities of the hot and cold target may be measured simultaneously. Afterwards, hydrodynamic effects create temperature and density gradients, which would obfuscate analysis of opacity data. We are using xRage to simulate heat flow within our targets in order to estimate the time scale over which temperature and density gradients evolve. These simulations will better inform our target design and diagnostic requirements. If successful, our experiments could yield the data necessary to validate existing opacity models or provide physical insights to inform the development of new opacity models. Accurate opacity models are essential to the understanding of radiation transport within HED systems, with applications ranging from astrophysics to ICF. U.S. Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant #DE-NA0001840. Los Alamos National Laboratory, LA-UR-15-25490.