Science.gov

Sample records for electromagnetics electron cooling

  1. Computational Electronics and Electromagnetics

    SciTech Connect

    DeFord, J.F.

    1993-03-01

    The Computational Electronics and Electromagnetics thrust area is a focal point for computer modeling activities in electronics and electromagnetics in the Electronics Engineering Department of Lawrence Livermore National Laboratory (LLNL). Traditionally, they have focused their efforts in technical areas of importance to existing and developing LLNL programs, and this continues to form the basis for much of their research. A relatively new and increasingly important emphasis for the thrust area is the formation of partnerships with industry and the application of their simulation technology and expertise to the solution of problems faced by industry. The activities of the thrust area fall into three broad categories: (1) the development of theoretical and computational models of electronic and electromagnetic phenomena, (2) the development of useful and robust software tools based on these models, and (3) the application of these tools to programmatic and industrial problems. In FY-92, they worked on projects in all of the areas outlined above. The object of their work on numerical electromagnetic algorithms continues to be the improvement of time-domain algorithms for electromagnetic simulation on unstructured conforming grids. The thrust area is also investigating various technologies for conforming-grid mesh generation to simplify the application of their advanced field solvers to design problems involving complicated geometries. They are developing a major code suite based on the three-dimensional (3-D), conforming-grid, time-domain code DSI3D. They continue to maintain and distribute the 3-D, finite-difference time-domain (FDTD) code TSAR, which is installed at several dozen university, government, and industry sites.

  2. Coherent electron cooling

    SciTech Connect

    Litvinenko,V.

    2009-05-04

    Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

  3. MEIC electron cooling program

    SciTech Connect

    Derbenev, Yaroslav S.; Zhang, Yuhong

    2014-12-01

    Cooling of proton and ion beams is essential for achieving high luminosities (up to above 1034 cm-2s-1) for MEIC, a Medium energy Electron-Ion Collider envisioned at JLab [1] for advanced nuclear science research. In the present conceptual design, we utilize the conventional election cooling method and adopted a multi-staged cooling scheme for reduction of and maintaining low beam emittances [2,3,4]. Two electron cooling facilities are required to support the scheme: one is a low energy (up to 2 MeV) DC cooler installed in the MEIC ion pre-booster (with the proton kinetic energy up to 3 GeV); the other is a high electron energy (up to 55 MeV) cooler in the collider ring (with the proton kinetic energy from 25 to 100 GeV). The high energy cooler, which is based on the ERL technology and a circulator ring, utilizes a bunched electron beam to cool bunched proton or ion beams. To complete the MEIC cooling concept and a technical design of the ERL cooler as well as to develop supporting technologies, an R&D program has been initiated at Jefferson Lab and significant progresses have been made since then. In this study, we present a brief description of the cooler design and a summary of the progress in this cooling R&D.

  4. MEIC electron cooling program

    DOE PAGESBeta

    Derbenev, Yaroslav S.; Zhang, Yuhong

    2014-12-01

    Cooling of proton and ion beams is essential for achieving high luminosities (up to above 1034 cm-2s-1) for MEIC, a Medium energy Electron-Ion Collider envisioned at JLab [1] for advanced nuclear science research. In the present conceptual design, we utilize the conventional election cooling method and adopted a multi-staged cooling scheme for reduction of and maintaining low beam emittances [2,3,4]. Two electron cooling facilities are required to support the scheme: one is a low energy (up to 2 MeV) DC cooler installed in the MEIC ion pre-booster (with the proton kinetic energy up to 3 GeV); the other is amore » high electron energy (up to 55 MeV) cooler in the collider ring (with the proton kinetic energy from 25 to 100 GeV). The high energy cooler, which is based on the ERL technology and a circulator ring, utilizes a bunched electron beam to cool bunched proton or ion beams. To complete the MEIC cooling concept and a technical design of the ERL cooler as well as to develop supporting technologies, an R&D program has been initiated at Jefferson Lab and significant progresses have been made since then. In this study, we present a brief description of the cooler design and a summary of the progress in this cooling R&D.« less

  5. Computational electronics and electromagnetics

    SciTech Connect

    Shang, C. C.

    1997-02-01

    The Computational Electronics and Electromagnetics thrust area at Lawrence Livermore National Laboratory serves as the focal point for engineering R&D activities for developing computer-based design, analysis, and tools for theory. Key representative applications include design of particle accelerator cells and beamline components; engineering analysis and design of high-power components, photonics, and optoelectronics circuit design; EMI susceptibility analysis; and antenna synthesis. The FY-96 technology-base effort focused code development on (1) accelerator design codes; (2) 3-D massively parallel, object-oriented time-domain EM codes; (3) material models; (4) coupling and application of engineering tools for analysis and design of high-power components; (5) 3-D spectral-domain CEM tools; and (6) enhancement of laser drilling codes. Joint efforts with the Power Conversion Technologies thrust area include development of antenna systems for compact, high-performance radar, in addition to novel, compact Marx generators. 18 refs., 25 figs., 1 tab.

  6. Electron Cooling of RHIC

    SciTech Connect

    I. Ben-Zvi; D.S. Barton; D.B. Beavis; M. Blaskiewicz; J.M. Brennan; A. Burrill; R. Calaga; P. Cameron; X.Y. Chang; R. Connolly; Yu.I. Eidelman; A.V. Fedotov; W. Fischer; D.M. Gassner; H. Hahn; M. Harrison; A. Hershcovitch; H.-C. Hseuh; A.K. Jain; P.D.J. Johnson; D. Kayran; J. Kewisch; R.F. Lambiase; V. Litvinenko; W.W. MacKay; G.J. Mahler; N. Malitsky; G.T. McIntyre; W. Meng; K.A.M. Mirabella; C. Montag; T.C.N. Nehring; T. Nicoletti; B. Oerter; G. Parzen; D. Pate; J. Rank; T. Rao; T. Roser; T. Russo; J. Scaduto; K. Smith; D. Trbojevic; G. Wang; J. Wei; N.W.W. Williams; K.-C. Wu; V. Yakimenko; A. Zaltsman; Y. Zhao; D.T. Abell; D.L. Bruhwiler; H. Bluem; A. Burger; M.D. Cole; A.J. Favale; D. Holmes; J. Rathke; T. Schultheiss; A.M.M. Todd; A.V. Burov; S. Nagaitsev; J.R. Delayen; Y.S. Derbenev; L. W. Funk; P. Kneisel; L. Merminga; H.L. Phillips; J.P. Preble; I. Koop; V.V. Parkhomchuk; Y.M. Shatunov; A.N. Skrinsky; I. Koop; V.V. Parkhomchuk; Y.M. Shatunov; A.N. Skrinsky; J.S. Sekutowicz

    2005-05-16

    We report progress on the R&D program for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This electron cooler is designed to cool 100 GeV/nucleon at storage energy using 54 MeV electrons. The electron source will be a superconducting RF photocathode gun. The accelerator will be a superconducting energy recovery linac. The frequency of the accelerator is set at 703.75 MHz. The maximum electron bunch frequency is 9.38 MHz, with bunch charge of 20 nC. The R&D program has the following components: The photoinjector and its photocathode, the superconducting linac cavity, start-to-end beam dynamics with magnetized electrons, electron cooling calculations including benchmarking experiments and development of a large superconducting solenoid. The photoinjector and linac cavity are being incorporated into an energy recovery linac aimed at demonstrating ampere class current at about 20 MeV. A Zeroth Order Design Report is in an advanced draft state, and can be found on the web at http://www.agsrhichome.bnl.gov/eCool/.

  7. ELECTRON COOLING FOR RHIC.

    SciTech Connect

    BEN-ZVI,I.

    2001-05-13

    The Accelerator Collider Department (CAD) at Brookhaven National Laboratory is operating the Relativistic Heavy Ion Collider (RHIC), which includes the dual-ring, 3.834 km circumference superconducting collider and the venerable AGS as the last part of the RHIC injection chain. CAD is planning on a luminosity upgrade of the machine under the designation RHIC II. One important component of the RHIC II upgrade is electron cooling of RHIC gold ion beams. For this purpose, BNL and the Budker Institute of Nuclear Physics in Novosibirsk entered into a collaboration aimed initially at the development of the electron cooling conceptual design, resolution of technical issues, and finally extend the collaboration towards the construction and commissioning of the cooler. Many of the results presented in this paper are derived from the Electron Cooling for RHIC Design Report [1], produced by the, BINP team within the framework of this collaboration. BNL is also collaborating with Fermi National Laboratory, Thomas Jefferson National Accelerator Facility and the University of Indiana on various aspects of electron cooling.

  8. ELECTRON COOLING STUDY FOR MEIC

    SciTech Connect

    He, Zhang; Douglas, David R.; Derbenev, Yaroslav S.; Zhang, Yuhong

    2015-09-01

    Electron cooling of the ion beams is one critical R&D to achieve high luminosities in JLab's MEIC proposal. In the present MEIC design, a multi-staged cooling scheme is adapted, which includes DC electron cooling in the booster ring and bunched beam electron cooling in the collider ring at both the injection energy and the collision energy. We explored the feasibility of using both magnetized and non-magnetized electron beam for cooling, and concluded that a magnetized electron beam is necessary. Electron cooling simulation results for the newly updated MEIC design is also presented.

  9. Dynamical backaction cooling with free electrons

    PubMed Central

    Niguès, A.; Siria, A.; Verlot, P.

    2015-01-01

    The ability to cool single ions, atomic ensembles, and more recently macroscopic degrees of freedom down to the quantum ground state has generated considerable progress and perspectives in fundamental and technological science. These major advances have been essentially obtained by coupling mechanical motion to a resonant electromagnetic degree of freedom in what is generally known as laser cooling. Here, we experimentally demonstrate the first self-induced coherent cooling mechanism that is not mediated by an electromagnetic resonance. Using a focused electron beam, we report a 50-fold reduction of the motional temperature of a nanowire. Our result primarily relies on the sub-nanometre confinement of the electron beam and generalizes to any delayed and spatially confined interaction, with important consequences for near-field microscopy and fundamental nanoscale dissipation mechanisms. PMID:26381454

  10. Dynamical backaction cooling with free electrons.

    PubMed

    Niguès, A; Siria, A; Verlot, P

    2015-01-01

    The ability to cool single ions, atomic ensembles, and more recently macroscopic degrees of freedom down to the quantum ground state has generated considerable progress and perspectives in fundamental and technological science. These major advances have been essentially obtained by coupling mechanical motion to a resonant electromagnetic degree of freedom in what is generally known as laser cooling. Here, we experimentally demonstrate the first self-induced coherent cooling mechanism that is not mediated by an electromagnetic resonance. Using a focused electron beam, we report a 50-fold reduction of the motional temperature of a nanowire. Our result primarily relies on the sub-nanometre confinement of the electron beam and generalizes to any delayed and spatially confined interaction, with important consequences for near-field microscopy and fundamental nanoscale dissipation mechanisms. PMID:26381454

  11. Dynamical backaction cooling with free electrons

    NASA Astrophysics Data System (ADS)

    Niguès, A.; Siria, A.; Verlot, P.

    2015-09-01

    The ability to cool single ions, atomic ensembles, and more recently macroscopic degrees of freedom down to the quantum ground state has generated considerable progress and perspectives in fundamental and technological science. These major advances have been essentially obtained by coupling mechanical motion to a resonant electromagnetic degree of freedom in what is generally known as laser cooling. Here, we experimentally demonstrate the first self-induced coherent cooling mechanism that is not mediated by an electromagnetic resonance. Using a focused electron beam, we report a 50-fold reduction of the motional temperature of a nanowire. Our result primarily relies on the sub-nanometre confinement of the electron beam and generalizes to any delayed and spatially confined interaction, with important consequences for near-field microscopy and fundamental nanoscale dissipation mechanisms.

  12. Electron Cooling of Bunched Beams

    SciTech Connect

    Uesugi, T.; Noda, K.; Syresin, E.; Meshkov, I.; Shibuya, S.

    2006-03-20

    Experiments of electron cooling have been done with the HIMAC synchrotron in NIRS. Limitation on cooled beam-sizes in longitudianl and transverse spaces were measured. The effect of space-charge field and intra-beam scattering are investigated.

  13. Power electronics cooling apparatus

    SciTech Connect

    Sanger, P.A.; Lindberg, F.A.; Garcen, W.

    2000-01-18

    A semiconductor cooling arrangement wherein a semiconductor is affixed to a thermally and electrically conducting carrier such as by brazing. The coefficient of thermal expansion of the semiconductor and carrier are closely matched to one another so that during operation they will not be overstressed mechanically due to thermal cycling. Electrical connection is made to the semiconductor and carrier, and a porous metal heat exchanger is thermally connected to the carrier. The heat exchanger is positioned within an electrically insulating cooling assembly having cooling oil flowing therethrough. The arrangement is particularly well adapted for the cooling of high power switching elements in a power bridge.

  14. Power electronics cooling apparatus

    SciTech Connect

    Sanger, Philip Albert; Lindberg, Frank A.; Garcen, Walter

    2000-01-01

    A semiconductor cooling arrangement wherein a semiconductor is affixed to a thermally and electrically conducting carrier such as by brazing. The coefficient of thermal expansion of the semiconductor and carrier are closely matched to one another so that during operation they will not be overstressed mechanically due to thermal cycling. Electrical connection is made to the semiconductor and carrier, and a porous metal heat exchanger is thermally connected to the carrier. The heat exchanger is positioned within an electrically insulating cooling assembly having cooling oil flowing therethrough. The arrangement is particularly well adapted for the cooling of high power switching elements in a power bridge.

  15. Direct cooled power electronics substrate

    DOEpatents

    Wiles, Randy H [Powell, TN; Wereszczak, Andrew A [Oak Ridge, TN; Ayers, Curtis W. [Kingston, TN; Lowe, Kirk T. [Knoxville, TN

    2010-09-14

    The disclosure describes directly cooling a three-dimensional, direct metallization (DM) layer in a power electronics device. To enable sufficient cooling, coolant flow channels are formed within the ceramic substrate. The direct metallization layer (typically copper) may be bonded to the ceramic substrate, and semiconductor chips (such as IGBT and diodes) may be soldered or sintered onto the direct metallization layer to form a power electronics module. Multiple modules may be attached to cooling headers that provide in-flow and out-flow of coolant through the channels in the ceramic substrate. The modules and cooling header assembly are preferably sized to fit inside the core of a toroidal shaped capacitor.

  16. Cooling system for electronic components

    SciTech Connect

    Anderl, William James; Colgan, Evan George; Gerken, James Dorance; Marroquin, Christopher Michael; Tian, Shurong

    2015-12-15

    Embodiments of the present invention provide for non interruptive fluid cooling of an electronic enclosure. One or more electronic component packages may be removable from a circuit card having a fluid flow system. When installed, the electronic component packages are coincident to and in a thermal relationship with the fluid flow system. If a particular electronic component package becomes non-functional, it may be removed from the electronic enclosure without affecting either the fluid flow system or other neighboring electronic component packages.

  17. Electronic cooling using thermoelectric devices

    SciTech Connect

    Zebarjadi, M.

    2015-05-18

    Thermoelectric coolers or Peltier coolers are used to pump heat in the opposite direction of the natural heat flux. These coolers have also been proposed for electronic cooling, wherein the aim is to pump heat in the natural heat flux direction and from hot spots to the colder ambient temperature. In this manuscript, we show that for such applications, one needs to use thermoelectric materials with large thermal conductivity and large power factor, instead of the traditionally used high ZT thermoelectric materials. We further show that with the known thermoelectric materials, the active cooling cannot compete with passive cooling, and one needs to explore a new set of materials to provide a cooling solution better than a regular copper heat sink. We propose a set of materials and directions for exploring possible materials candidates suitable for electronic cooling. Finally, to achieve maximum cooling, we propose to use thermoelectric elements as fins attached to copper blocks.

  18. Enhancement of electromagnetically induced transparency cooling by an optical cavity

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; Zhang, Shuo; Ou, Bao-Quan; Wu, Wei; Chen, Ping-Xing

    2014-11-01

    We theoretically investigate an enhanced electromagnetically induced transparency (EIT) cooling method by introducing a high finesse cavity. We find that the quantum destructive interference that is induced by the EIT effect and the cavity coupling can eliminate all of the heating effects in the cooling process by choosing appropriate parameters. Compared with the EIT cooling scheme, a lower final temperature can be obtained under the same conditions in our scheme.

  19. Optimization of electron cooling in the Recycler

    SciTech Connect

    Shemyakin, A.; Burov, A.; Carlson, K.; Prost, L.R.; Sutherland, M.; Warner, A.; /Fermilab

    2009-04-01

    Antiprotons in Fermilab's Recycler ring are cooled by a 4.3 MeV, 0.1A DC electron beam (as well as by a stochastic cooling system). The paper describes electron cooling improvements recently implemented: adjustments of electron beam line quadrupoles to decrease the electron angles in the cooling section and better stabilization and control of the electron energy.

  20. Energy Efficient Electronics Cooling Project

    SciTech Connect

    Steve O'Shaughnessey; Tim Louvar; Mike Trumbower; Jessica Hunnicutt; Neil Myers

    2012-02-17

    Parker Precision Cooling Business Unit was awarded a Department of Energy grant (DE-EE0000412) to support the DOE-ITP goal of reducing industrial energy intensity and GHG emissions. The project proposed by Precision Cooling was to accelerate the development of a cooling technology for high heat generating electronics components. These components are specifically related to power electronics found in power drives focused on the inverter, converter and transformer modules. The proposed cooling system was expected to simultaneously remove heat from all three of the major modules listed above, while remaining dielectric under all operating conditions. Development of the cooling system to meet specific customer's requirements and constraints not only required a robust system design, but also new components to support long system functionality. Components requiring further development and testing during this project included pumps, fluid couplings, cold plates and condensers. All four of these major categories of components are required in every Precision Cooling system. Not only was design a key area of focus, but the process for manufacturing these components had to be determined and proven through the system development.

  1. The HESR Electron Cooling Proposal

    SciTech Connect

    Reistad, D.

    2006-03-20

    The maximum electron energy of the HESR electron cooling system has been decided to be 4.5 MeV, with a possible future upgrade to 8 MeV. Calculations with BETACOOL have been carried out; these include effects of imperfections of the electron beam as well as the internal hydrogen pellet target and intra-beam scattering. Design work is going on. This makes use of the experience gained at the FNAL Recycler and aims to result in a practical solution, which includes considerations for robustness as well as ease of assembly, bake-out, and to make use of proven solutions as much as possible.

  2. Coherent electron cooling demonstration experiment

    SciTech Connect

    Litvinenko, V.N.; Belomestnykh, S.; Ben-Zvi, I.; Brutus, J.C.; Fedotov, A.; Hao, Y.; Kayran, D.; Mahler, G.; Marusic, A.; Meng, W.; McIntyre, G.; Minty, M.; Ptitsyn, V.; Pinayev, I.; Rao, T.; Roser, T.; Sheehy, B.; Tepikian, S.; Than, R.; Trbojevic, D.; Tuozzolo, J.; Wang, G.; Yakimenko, V.; Hutton, A.; Krafft, G.; Poelker, M.; Rimmer, R.; Bruhwiler, D.; Abell, D.T.; Nieter, C.; Ranjbar, V.; Schwartz, B.; Kholopov M.; Shevchenko, O.; McIntosh, P.; Wheelhouse, A.

    2011-09-04

    Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using SRF linac. In this paper, we describe the setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC. We plan to complete the program in five years. During first two years we will build coherent electron cooler in IP2 of RHIC. In parallel we will develop complete package of computer simulation tools for the start-to-end simulation predicting exact performance of a CeC. The later activity will be the core of Tech X involvement into the project. We will use these tools to predict the performance of our CeC device. The experimental demonstration of the CeC will be undertaken in years three to five of the project. The goal of this experiment is to demonstrate the cooling of ion beam and to compare its measured performance with predictions made by us prior to the experiments.

  3. Towards demonstration of electron cooling with bunched electron beam

    SciTech Connect

    Fedotov, A.

    2012-01-11

    All electron cooling systems which were in operation so far employed electron beam generated with an electrostatic electron gun in DC operating mode, immersed in a longitudinal magnetic field. At low energies magnetic field is also being used to transport electron beam through the cooling section from the gun to the collector. At higher energies (few MeV), it was shown that one can have simpler electron beam transport without continuous magnetic field. Because of a rather weak magnetic field on the cathode and in the cooling section the latter approach was referred to as 'non-magnetized cooling', since there was no suppression of the transverse angular spread of the electron beam with the magnetic field in the cooling section. Such a cooler successfully operated at FNAL (2005-11) at electron beam energy of 4.3 MeV. Providing cooling at even higher energies would be easier with RF acceleration of electron beam, and thus using bunched electron beam for cooling. Significant efforts were devoted to explore various aspects of such bunched electron beam cooling as part of R and D of high-energy electron cooling for RHIC. However, experimental studies of such cooling are still lacking. Establishing this technique experimentally would be extremely useful for future high-energy applications. Presently there is an ongoing effort to build Proof-of-Principle (PoP) experiment of Coherent Electron Cooling (CEC) at RHIC, which promises to be superior to conventional electron cooling for high energies. Since the CEC experiment is based on bunched electron beam and it has sections where electron beam co-propagates with the ion beam at the same velocity, it also provides a unique opportunity to explore experimentally conventional electron cooling but for the first time with a bunched electron beam. As a result, it allows us to explore techniques needed for the high-energy electron cooling such as 'painting' with a short electron beam and control of ion beam distribution under cooling which is essential if cooling is provided in a collider. The software needed for comparison with the experiments is already developed as part of the previous high-energy electron cooling studies for RHIC. Since electron beam will be non-magnetized and there will be no magnetic field in the cooling section it will be also a first demonstration of fully non-magnetized cooling. The purpose of these studies was to explore whether we would be able to observe conventional electron cooling with parameters expected in the CEC PoP experiment. Below we summarize requirements on electron beam and cooling section needed for such demonstration.

  4. MEIC Electron Cooling Simulation Using Betacool

    SciTech Connect

    Zhang, He; Zhang, Yuhong

    2013-12-01

    Electron cooling of ion beams is the most critical R&D issue in Jefferson Lab's MEIC design. In the ion collider ring, a bunched electron beam driven by an energy-recovery SRF linac assisted by a circulate ring will be employed to cool protons or ions with energies up to 100 GeV/u, a parameter regime that electron cooling has never been applied. It is essential to understand how efficient the electron cooling is, particularly in the high energy range, to confirm the feasibility of the design. Electron cooling is also important in LEIC design although the ion energy is 25 GeV/u, lower than MEIC. In this paper, we will present first results of the simulation studies of electron cooling processes in the collider ring of both MEIC and LEIC using BETACOOL code.

  5. Experimental demonstration of relativistic electron cooling.

    PubMed

    Nagaitsev, Sergei; Broemmelsiek, Daniel; Burov, Alexey; Carlson, Kermit; Gattuso, Consolato; Hu, Martin; Kroc, Thomas; Prost, Lionel; Pruss, Stanley; Sutherland, Mary; Schmidt, Charles W; Shemyakin, Alexander; Tupikov, Vitali; Warner, Arden; Kazakevich, Grigory; Seletskiy, Sergey

    2006-02-01

    We report on an experimental demonstration of electron cooling of high-energy antiprotons circulating in a storage ring. In our experiments, electron cooling, a well-established method at low energies (<500 MeV/nucleon), was carried out in a new region of beam parameters, requiring a multi-MeV dc electron beam and an unusual beam transport line. In this Letter, we present the results of the longitudinal cooling force measurements and compare them with theoretical predictions. PMID:16486833

  6. Experimental demonstration of relativistic electron cooling

    SciTech Connect

    Nagaitsev, S.; Broemmelsiek, D.; Burov, Alexey V.; Carlson, K.; Gattuso, C.; Hu, M.; Kazakevich, Grigory M.; Kroc, T.; Prost, L.; Pruss, S.; Sutherland, M.; Schmidt, C.W.; Seletskiy, S.; Shemyakin, A.; Tupikov, V.; Warner, A.; /Fermilab /Novosibirsk, IYF /Rochester U.

    2005-11-01

    We report on an experimental demonstration of electron cooling of high-energy antiprotons circulating in a storage ring. In our experiments, electron cooling, a well-established method at low energies (< 500 MeV/nucleon), was carried out in a new region of beam parameters, requiring a multi-MeV dc electron beam and an unusual beam transport line. In this letter we present the results of the longitudinal cooling force measurements and compare them with theoretical predictions.

  7. Classical electromagnetic radiation of the Dirac electron

    NASA Technical Reports Server (NTRS)

    Lanyi, G.

    1973-01-01

    A wave-function-dependent four-vector potential is added to the Dirac equation in order to achieve conservation of energy and momentum for a Dirac electron and its emitted electromagnetic field. The resultant equation contains solutions which describe transitions between different energy states of the electron. As a consequence it is possible to follow the space-time evolution of such a process. This evolution is shown in the case of the spontaneous emission of an electromagnetic field by an electron bound in a hydrogen-like atom. The intensity of the radiation and the spectral distribution are calculated for transitions between two eigenstates. The theory gives a self-consistent deterministic description of some simple radiation processes without using quantum electrodynamics or the correspondence principle.

  8. A novel electronic cooling concept

    NASA Astrophysics Data System (ADS)

    Ponnappan, R.; Beam, J. E.

    Advanced electrical power conditioning systems for the More Electric Aircraft Initiative involve high currents and high voltages with the attendant waste heat generation and cooling problems. The use of solid state switching devices such as MCTs for these systems will result in power dissipation of several hundred Watts per square centimeter. Conventional forced air or low velocity single phase fluid cooling is inadequate to handle the waste heat dissipation of these high power devices. More advanced and innovative methods of cooling which can use fluids available in the aircraft and also easy to package are sought. A new approach called 'venturi flow cooling concept' is described. It is shown that localized cooling up to 200 W/sq cm is possible at the venturi throat region where the MCTs can be mounted. PAO coolant with Pr = 56 at 40 C can be conveniently used in aircraft.

  9. Electron kinetics in a cooling plasma

    SciTech Connect

    Helander, P.; Smith, H.; Fueloep, T.; Eriksson, L.-G.

    2004-12-01

    The distribution function of suprathermal electrons in a slowly cooling plasma is calculated by an asymptotic expansion in the cooling rate divided by the collision frequency. Since the collision frequency decreases with increasing velocity, a high-energy tail forms in the electron distribution function as the bulk population cools down. Under certain simplifying assumptions (slow cooling, constant density, Born approximation of cross sections), the distribution function evolves to a self-similar state where the tail is inversely proportional to the cube of the velocity. Its practical consequences are discussed briefly.

  10. Direct Liquid Cooling for Electronic Equipment

    SciTech Connect

    Coles, Henry; Greenberg, Steve

    2014-03-01

    This report documents a demonstration of an electronic--equipment cooling system in the engineering prototype development stage that can be applied in data centers. The technology provides cooling by bringing a water--based cooling fluid into direct contact with high--heat--generating electronic components. This direct cooling system improves overall data center energy efficiency in three ways: High--heat--generating electronic components are more efficiently cooled directly using water, capturing a large portion of the total electronic equipment heat generated. This captured heat reduces the load on the less--efficient air--based data center room cooling systems. The combination contributes to the overall savings. The power consumption of the electronic equipment internal fans is significantly reduced when equipped with this cooling system. The temperature of the cooling water supplied to the direct cooling system can be much higher than that commonly provided by facility chilled water loops, and therefore can be produced with lower cooling infrastructure energy consumption and possibly compressor-free cooling. Providing opportunities for heat reuse is an additional benefit of this technology. The cooling system can be controlled to produce high return water temperatures while providing adequate component cooling. The demonstration was conducted in a data center located at Lawrence Berkeley National Laboratory in Berkeley, California. Thirty--eight servers equipped with the liquid cooling system and instrumented for energy measurements were placed in a single rack. Two unmodified servers of the same configuration, located in an adjacent rack, were used to provide a baseline. The demonstration characterized the fraction of heat removed by the direct cooling technology, quantified the energy savings for a number of cooling infrastructure scenarios, and provided information that could be used to investigate heat reuse opportunities. Thermal measurement data were used with data center energy use modeling software to estimate overall site energy use. These estimates show that an overall data center energy savings of approximately 20 percent can be expected if a center is retrofitted as specified in the models used. Increasing the portion of heat captured by this technology is an area suggested for further development.

  11. ELECTRON COOLING IN THE RECYCLER COOLER

    SciTech Connect

    SHEMYAKIN,A.; PROST, L.R.; FEDOTOV, A.; SIDORIN, A.

    2007-09-10

    A 0.1-0.5 A, 4.3 MeV DC electron beam provides cooling of 8 GeV antiprotons in Fermilab's Recycler storage ring. The most detailed information about the cooling properties of the electron beam comes from drag rate measurements. We find that the measured drag rate can significantly differ from the cooling force experienced by a single antiproton because the area of effective cooling is significantly smaller than the physical size of the electron beam and is comparable with the size of the antiproton beam used as a probe. Modeling by the BETACOOL code supports the conclusion about a large radial gradient of transverse velocities in the presently used electron beam.

  12. DETAILED STUDIES OF ELECTRON COOLING FRICTION FORCE.

    SciTech Connect

    FEDOTOV, A.V.; BRUHWILER, D.L.; ABELL, D.T.; SIDORIN, A.O.

    2005-09-18

    High-energy electron cooling for RHIC presents many unique features and challenges. An accurate estimate of the cooling times requires detailed simulation of the electron cooling process. The first step towards such calculations is to have an accurate description of the cooling force. Numerical simulations are being used to explore various features of the friction force which appear due to several effects, including the anisotropy of the electron distribution in velocity space and the effect of a strong solenoidal magnetic field. These aspects are being studied in detail using the VORFAL code, which explicitly resolves close binary collisions. Results are compared with available asymptotic and empirical formulas and also, using the BETACOOL code, with direct numerical integration of less approximate expressions over the specified electron distribution function.

  13. Detailed Studies of Electron Cooling Friction Force

    SciTech Connect

    Fedotov, A. V.; Bruhwiler, D. L.; Abell, D. T.; Sidorin, A. O.

    2006-03-20

    High-energy electron cooling for RHIC presents many unique features and challenges. An accurate estimate of the cooling times requires detailed simulation of the electron cooling process. The first step towards such calculations is to have an accurate description of the cooling force. Numerical simulations are being used to explore various features of the friction force which appear due to several effects, including the anisotropy of the electron distribution in velocity space and the effect of a strong solenoidal magnetic field. These aspects are being studied in detail using the VORPAL code, which explicitly resolves close binary collisions. Results are compared with available asymptotic and empirical formulas and also, using the BETACOOL code, with direct numerical integration of less approximate expressions over the specified electron distribution function.

  14. Luminosity Potentials in Colliders with Electron Cooling

    SciTech Connect

    Derbenev, Yaroslav

    2003-05-01

    Luminosity upgrades of colliders with hadron beams, existing or designed, tend to require decreasing of beam emittances and maintaining them using a suitable cooling technique. The breakthroughs of recent years: realization of beam energy recovery in superconducting linear accelerators, flat to round beam transformations, new beam transport concepts (discontinuous solenoid, circulator rings, hollow beams, dispersive cooling) ? have promoted the feasibility of efficient electron cooling of intense high energy hadron beams. Electron cooling, in cooperation with strong SRF field in storage rings, will allow one to obtain very short hadron bunches, as result of which the luminosity can be raised by making a low beta-star. Short bunches also would makecrab crossing feasible, that allows one to remove the parasitic beam-beam interactions and maximize the collision rate. Cooling also results in flatness of uncoupled beam equilibrium; this can be used to diminish the IBS impact on luminosity

  15. Simulation study of electron response amplification in coherent electron cooling

    SciTech Connect

    Hao Y.; Litvinenko, V.N.

    2012-05-20

    In Coherent Electron Cooling (CEC), it is essential to study the amplification of electron response to a single ion in the FEL process, in order to proper align the electron beam and the ion beam in the kicker to maximize the cooling effect. In this paper, we use Genesis to simulate the amplified electron beam response of single ion in FEL amplification process, which acts as Green's function of the FEL amplifier.

  16. Electronic systems failures and anomalies attributed to electromagnetic interference

    NASA Technical Reports Server (NTRS)

    Leach, R. D. (Editor); Alexander, M. B. (Editor)

    1995-01-01

    The effects of electromagnetic interference can be very detrimental to electronic systems utilized in space missions. Assuring that subsystems and systems are electrically compatible is an important engineering function necessary to assure mission success. This reference publication will acquaint the reader with spacecraft electronic systems failures and anomalies caused by electromagnetic interference and will show the importance of electromagnetic compatibility activities in conjunction with space flight programs. It is also hoped that the report will illustrate that evolving electronic systems are increasingly sensitive to electromagnetic interference and that NASA personnel must continue to diligently pursue electromagnetic compatibility on space flight systems.

  17. Fluctuating electromagnetic fields and electron coherence

    NASA Astrophysics Data System (ADS)

    Hsiang, Jen-Tsung

    It is well-known that a charged particle in a constant magnetic field background will acquire a phase, the Aharonov-Bohm phase, which depends on the path it travels and on the strength of the background field. This effect has long been recognized and experimentally verified. However, the effect of a fluctuating Aharonov-Bohm phase was first discussed in the works of Stern, et al., and Ford. There authors showed that such a fluctuating phase leads to decoherence. In this thesis, the effect of external time-varying and fluctuating electromagnetic fields on electron coherence is investigated. We will analyze the electron interference patterns under influence of different external fluctuating sources. The possibility of observable effects is discussed. We show that for a linearly polarized, time-varying classical beam, the decoherence effect is large enough to be observable. Further, there exists a unique feature of this form of decoherence that could be easily identified in an experiment. We also point out that in general the effect of diffraction is not negligible, so we have to be careful about the assumptions made on the diffraction properties of the beam. We also show that the effect of vacuum fluctuations and photon emission can cause decoherence. This effect depends on the square of the transverse velocity of the electrons, so it is small in the non-relativistic limit. Also, we demonstrate that in order to avoid an unphysical result due to infinite radiated energy, the path of the electron should satisfy certain smoothness conditions. Moreover, we prove that for a long, perfectly conducting wave guide with arbitrary cross section, the contrast of the interference fringes does not depends on the field configuration inside the wave guide. We further argue that inside the guide, this result can be generalized to the quantized electromagnetic fields in very general quantum states. A few remarks are made about the feasibility of including finite conductivity corrections. The issue of recoherence is discussed in the context of electromagnetic fields in a squeezed vacuum state. We find that if we carefully sample the electrons, we can observe an enhancement of electron coherence. We discussed possible limits on our ability to boost the interference contrast.

  18. Thermoelectric Devices Cool, Power Electronics

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Nextreme Thermal Solutions Inc., based in Research Triangle Park, North Carolina, licensed thermoelectric technology from NASA s Jet Propulsion Laboratory. This has allowed the company to develop cutting edge, thin-film thermoelectric coolers that effective remove heat generated by increasingly powerful and tightly packed microchip components. These solid-state coolers are ideal solutions for applications like microprocessors, laser diodes, LEDs, and even potentially for cooling the human body. Nextreme s NASA technology has also enabled the invention of thermoelectric generators capable of powering technologies like medical implants and wireless sensor networks.

  19. Methods and apparatus for cooling electronics

    DOEpatents

    Hall, Shawn Anthony; Kopcsay, Gerard Vincent

    2014-12-02

    Methods and apparatus are provided for choosing an energy-efficient coolant temperature for electronics by considering the temperature dependence of the electronics' power dissipation. This dependence is explicitly considered in selecting the coolant temperature T.sub.0 that is sent to the equipment. To minimize power consumption P.sub.Total for the entire system, where P.sub.Total=P.sub.0+P.sub.Cool is the sum of the electronic equipment's power consumption P.sub.0 plus the cooling equipment's power consumption P.sub.Cool, P.sub.Total is obtained experimentally, by measuring P.sub.0 and P.sub.Cool, as a function of three parameters: coolant temperature T.sub.0; weather-related temperature T.sub.3 that affects the performance of free-cooling equipment; and computational state C of the electronic equipment, which affects the temperature dependence of its power consumption. This experiment provides, for each possible combination of T.sub.3 and C, the value T.sub.0* of T.sub.0 that minimizes P.sub.Total. During operation, for any combination of T.sub.3 and C that occurs, the corresponding optimal coolant temperature T.sub.0* is selected, and the cooling equipment is commanded to produce it.

  20. Power electronics substrate for direct substrate cooling

    DOEpatents

    Le, Khiet; Ward, Terence G.; Mann, Brooks S.; Yankoski, Edward P.; Smith, Gregory S.

    2012-05-01

    Systems and apparatus are provided for power electronics substrates adapted for direct substrate cooling. A power electronics substrate comprises a first surface configured to have electrical circuitry disposed thereon, a second surface, and a plurality of physical features on the second surface. The physical features are configured to promote a turbulent boundary layer in a coolant impinged upon the second surface.

  1. Single Pass Electron Cooling Simulations for MEIC

    SciTech Connect

    Bell, G. I.; Pogorelov, I. V.; Schwartz, B. T.; Zhang, Yuhong; Zhang, He

    2013-12-01

    Cooling of medium energy protons is critical for the proposed Jefferson Lab Medium Energy Ion Collider (MEIC). We present simulations of electron cooling of protons up to 60 GeV. In the beam frame in which the proton and electrons are co-propagating, their motion is non-relativistic. We use a binary collision model which treats the cooling process as the sum of a large number of two-body collisions which are calculated exactly. This model can treat even very close collisions between an electron and ion with high accuracy. We also calculate dynamical friction using a delta-f PIC model. The code VSim (formerly Vorpal) is used to perform the simulations. We compare the friction rates with that obtained by a 3D integral over electron velocities which is used by BETACOOL.

  2. Method of fabricating a cooled electronic system

    DOEpatents

    Chainer, Timothy J; Gaynes, Michael A; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Schultz, Mark D; Simco, Daniel P; Steinke, Mark E

    2014-02-11

    A method of fabricating a liquid-cooled electronic system is provided which includes an electronic assembly having an electronics card and a socket with a latch at one end. The latch facilitates securing of the card within the socket. The method includes providing a liquid-cooled cold rail at the one end of the socket, and a thermal spreader to couple the electronics card to the cold rail. The thermal spreader includes first and second thermal transfer plates coupled to first and second surfaces on opposite sides of the card, and thermally conductive extensions extending from end edges of the plates, which couple the respective transfer plates to the liquid-cooled cold rail. The extensions are disposed to the sides of the latch, and the card is securable within or removable from the socket using the latch without removing the cold rail or the thermal spreader.

  3. Effect of cooling rate on structural and electromagnetic properties of high-carbon ferrochrome powders

    NASA Astrophysics Data System (ADS)

    Yang, Jian-ping; Chen, Jin; Hao, Jiu-jiu; Guo, Li-na; Liu, Jin-ying

    2016-03-01

    The structural and electromagnetic properties of high-carbon ferrochrome powders (HCFCP) obtained at different cooling rates were respectively investigated by means of optical microscope, X-ray diffractometer, electron probe as well as the vector network analyzer in the frequency range of 1-18 GHz. The results show that the cell structure of main phase, (Cr,Fe)7C3, transforms from hexagonal to orthogonal with the improvement of cooling rate. Meanwhile the mass ratio of Cr to Fe in (Cr,Fe)7C3 gradually declines, while that for CrFe goes up. Both the real part and the imaginary part of relative complex permittivity of HCFCP are in an increasing order with cooling rate rising in most frequencies. For comparison, the relative complex permeability presents an opposite changing tendency. The peaks of the imaginary part of relative complex permeability appearing in low and high frequencies are attributed to nature resonance. The reflection loss of HCFCP gradually decreases as cooling rate reduces and frequency enhances. At 2.45 GHz, the algebraic sum of dielectric loss factor and magnetic loss factor increases first and then decreases in the temperature extent from 298 K to 1273 K.

  4. IBS FOR ION DISTRIBUTION UNDER ELECTRON COOLING.

    SciTech Connect

    FEDOTOV,A.V.; BEN-ZVI,I.; EIDELMAN, YU.; LITVINENKO, V.; PARZEN, G.

    2005-05-16

    Standard models of the intra-beam scattering (IBS) are based on the growth of the rms beam parameters for a Gaussian distribution. As a result of electron cooling, the core of beam distribution is cooled much faster than the tails, producing a denser core. In this paper, we compare various approaches to IBS treatment for such distribution. Its impact on the luminosity is also discussed.

  5. Electron Cooling of Intense Ion Beam

    SciTech Connect

    Dietrich, J.; Kamerdjiev, V.; Maier, R.; Prasuhn, D.; Stein, J.; Stockhorst, H.; Korotaev, Yu.; Meshkov, I.; Sidorin, A.; Smirnov, A.

    2006-03-20

    Results of experimental studies of the electron cooling of a proton beam at COSY (Juelich, Germany) are presented. Intensity of the proton beam is limited by two general effects: particle loss directly after the injection and development of instability in a deep cooled ion beam. Results of the instability investigations performed at COSY during last years are presented in this report in comparison with previous results from HIMAC (Chiba, Japan) CELSIUS (Uppsala, Sweden) and LEAR (CERN). Methods of the instability suppression, which allow increasing the cooled beam intensity, are described. This work is supported by RFBR grant no. 05-02-16320 and INTAS grant no. 03-54-5584.

  6. Direct-Cooled Power Electronics Substrate

    SciTech Connect

    Wiles, R.; Ayers, C.; Wereszczak, A.

    2008-12-23

    The goal of the Direct-Cooled Power Electronics Substrate project is to reduce the size and weight of the heat sink for power electronics used in hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs). The concept proposed in this project was to develop an innovative power electronics mounting structure, model it, and perform both thermal and mechanical finite-element analysis (FEA). This concept involved integrating cooling channels within the direct-bonded copper (DBC) substrate and strategically locating these channels underneath the power electronic devices. This arrangement would then be directly cooled by water-ethylene glycol (WEG), essentially eliminating the conventional heat sink and associated heat flow path. The concept was evaluated to determine its manufacturability, its compatibility with WEG, and the potential to reduce size and weight while directly cooling the DBC and associated electronics with a coolant temperature of 105 C. This concept does not provide direct cooling to the electronics, only direct cooling inside the DBC substrate itself. These designs will take into account issues such as containment of the fluid (separation from the electronics) and synergy with the whole power inverter design architecture. In FY 2008, mechanical modeling of substrate and inverter core designs as well as thermal and mechanical stress FEA modeling of the substrate designs was performed, along with research into manufacturing capabilities and methods that will support the substrate designs. In FY 2009, a preferred design(s) will be fabricated and laboratory validation testing will be completed. In FY 2010, based on the previous years laboratory testing, the mechanical design will be modified and the next generation will be built and tested in an operating inverter prototype.

  7. Electron cooling rates characterization at Fermilab's Recycler

    SciTech Connect

    Prost, Lionel R.; Shemyakin, A.; /Fermilab

    2007-06-01

    A 0.1 A, 4.3 MeV DC electron beam is routinely used to cool 8 GeV antiprotons in Fermilab's Recycler storage ring [1]. The primary function of the electron cooler is to increase the longitudinal phase-space density of the antiprotons for storing and preparing high-density bunches for injection into the Tevatron. The longitudinal cooling rate is found to significantly depend on the transverse emittance of the antiproton beam. The paper presents the measured rates and compares them with calculations based on drag force data.

  8. FREE ELECTRON LASERS AND HIGH-ENERGY ELECTRON COOLING.

    SciTech Connect

    LITVINENKO,V.N.

    2007-08-31

    Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation of such beams is too feeble to provide significant cooling: even in the Large Hadron Collider (LHC) with 7 TeV protons, the longitudinal damping time is about thirteen hours. Decrements of traditional electron cooling decrease rapidly as the high power of beam energy, and an effective electron cooling of protons or antiprotons at energies above 100 GeV seems unlikely. Traditional stochastic cooling still cannot catch up with the challenge of cooling high-intensity bunched proton beams--to be effective, its bandwidth must be increased by about two orders-of-magnitude. Two techniques offering the potential to cool high-energy hadron beams are optical stochastic cooling (OSC) and coherent electron cooling (CEC)--the latter is the focus of this paper. In the early 1980s, CEC was suggested as a possibility for using various instabilities in an electron beam to enhance its interaction with hadrons (i.e., cooling them). The capabilities of present-day accelerator technology, Energy Recovery Linacs (ERLs), and high-gain Free-Electron Lasers (FELs), finally caught up with the idea and provided the all necessary ingredients for realizing such a process. In this paper, we discuss the principles, and the main limitations of the CEC process based on a high-gain FEL driven by an ERL. We also present, and summarize in Table 1, some numerical examples of CEC for ions and protons in RHIC and the LHC.

  9. Potential Refrigerants for Power Electronics Cooling

    SciTech Connect

    Starke, M.R.

    2005-10-24

    In the past, automotive refrigerants have conventionally been used solely for the purpose of air conditioning. However, with the development of hybrid-electric vehicles and the incorporation of power electronics (PEs) into the automobile, automotive refrigerants are taking on a new role. Unfortunately, PEs have lifetimes and functionalities that are highly dependent on temperature and as a result thermal control plays an important role in the performance of PEs. Typically, PEs are placed in the engine compartment where the internal combustion engine (ICE) already produces substantial heat. Along with the ICE heat, the additional thermal energy produced by PEs themselves forces designers to use different cooling methods to prevent overheating. Generally, heat sinks and separate cooling loops are used to maintain the temperature. Disturbingly, the thermal control system can consume one third of the total volume and may weigh more than the PEs [1]. Hence, other avenues have been sought to cool PEs, including submerging PEs in automobile refrigerants to take advantage of two-phase cooling. The objective of this report is to explore the different automotive refrigerants presently available that could be used for PE cooling. Evaluation of the refrigerants will be done by comparing environmental effects and some thermo-physical properties important to two-phase cooling, specifically measuring the dielectric strengths of potential candidates. Results of this report will be used to assess the different candidates with good potential for future use in PE cooling.

  10. Cooling of electronics in collider experiments

    SciTech Connect

    Richard P. Stanek et al.

    2003-11-07

    Proper cooling of detector electronics is critical to the successful operation of high-energy physics experiments. Collider experiments offer unique challenges based on their physical layouts and hermetic design. Cooling systems can be categorized by the type of detector with which they are associated, their primary mode of heat transfer, the choice of active cooling fluid, their heat removal capacity and the minimum temperature required. One of the more critical detector subsystems to require cooling is the silicon vertex detector, either pixel or strip sensors. A general design philosophy is presented along with a review of the important steps to include in the design process. Factors affecting the detector and cooling system design are categorized. A brief review of some existing and proposed cooling systems for silicon detectors is presented to help set the scale for the range of system designs. Fermilab operates two collider experiments, CDF & D0, both of which have silicon systems embedded in their detectors. A review of the existing silicon cooling system designs and operating experience is presented along with a list of lessons learned.

  11. Two-Beam Instability in Electron Cooling

    SciTech Connect

    Burov, Alexey V.; /Fermilab

    2006-04-01

    The drift motion of cooling electrons makes them able to respond to transverse perturbations of a cooled ion beam. This response may lead to dipole or quadrupole transverse instabilities at specific longitudinal wave numbers. While the dipole instabilities can be suppressed by a combination of the Landau damping, machine impedance, and the active damper, the quadrupole and higher order modes can lead to either emittance growth, or a lifetime degradation, or both. The growth rates of these instabilities are strongly determined by the machine x-y coupling. Thus, tuning out of the coupling resonance and/or reduction of the machine coupling can be an efficient remedy for these instabilities.

  12. Electron Beam Size Measurements in the Fermilab Electron Cooling System

    SciTech Connect

    Kroc, T. K.; Burov, A. V.; Bolshakov, T. B.; Shemyakin, A.; Seletskiy, S. M.

    2006-03-20

    The Fermilab Electron Cooling Project requires a straight trajectory and constant beam size to provide maximum cooling of the antiprotons in the Recycler. A measurement system was developed using movable apertures and steering bumps to measure the beam size in a 20m long, nearly continuous, solenoid. This paper will focus on results of these measurements of the beam size and the difficulties in making those measurements.

  13. Electron beam size measurements in the Fermilab Electron Cooling System

    SciTech Connect

    Kroc, T.K.; Burov, A.V.; Bolshakov, T.B.; Shemyakin, A.; Seletskiy, S.M.; /Rochester U.

    2005-09-01

    The Fermilab Electron Cooling Project requires a straight trajectory and constant beam size to provide maximum cooling of the antiprotons in the Recycler. A measurement system was developed using movable apertures and steering bumps to measure the beam size in a 20m long, nearly continuous, solenoid. This paper will focus on results of these measurements of the beam size and the difficulties in making those measurements.

  14. ELECTRON COOLING SIMULATION FOR ARBITRARY DISTRIBUTION OF ELECTRONS

    SciTech Connect

    SIDORIN,A.; SMIRNOV, A.; FEDOTOV, A.; BEN-ZVI, I.; KAYRAN, D.

    2007-09-10

    Typically, several approximations are being used in simulation of electron cooling process, for example, density distribution of electrons is calculated using an analytical expression and distribution in the velocity space is assumed to be Maxwellian in all degrees of freedom. However, in many applications, accurate description of the cooling process based on realistic distribution of electrons is very useful. This is especially true for a high-energy electron cooling system which requires bunched electron beam produced by an Energy Recovery Linac (Em). Such systems are proposed, for instance, for RHIC and electron - ion collider. To address unique features of the RHIC-I1 cooler, new algorithms were introduced in BETACOOL code which allow us to take into account local properties of electron distribution as well as calculate friction force for an arbitrary velocity distribution. Here, we describe these new numerical models. Results based on these numerical models are compared with typical approximations using electron distribution produced by simulations of electron bunch through ERL of RHIC-II cooler.

  15. Survey and Alignment of the Fermilab Electron Cooling System

    SciTech Connect

    Oshinowo, Babatunde O'Sheg; Leibfritz, Jerry

    2006-09-01

    The goal of achieving the Tevatron luminosity of 3 x 10{sup 32} cm{sup -2}s{sup -1} requires Electron Cooling in the Recycler Ring to provide an increased flux of antiprotons. The Fermilab Electron Cooling system has been designed to assist accumulation of antiprotons for the Tevatron collider operations. The installation along with the survey and alignment of the Electron Cooling system in the Recycler Ring were completed in November 2004. The Electron Cooling system was fully commissioned in May 2005 and the first cooling of antiprotons was achieved in July 2005. This paper discusses the alignment methodology employed to survey and align the Electron Cooling system.

  16. Cooled electronic system with liquid-cooled cold plate and thermal spreader coupled to electronic component

    DOEpatents

    Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.; Kamath, Vinod; Kochuparambil, Bejoy J.; Schmidt, Roger R.; Steinke, Mark E.

    2016-04-05

    Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to be cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.

  17. Electromagnetically-induced-transparency-like ground-state cooling in a double-cavity optomechanical system

    NASA Astrophysics Data System (ADS)

    Guo, Yujie; Li, Kai; Nie, Wenjie; Li, Yong

    2014-11-01

    We propose to cool a mechanical resonator close to its ground state via an electromagnetically-induced-transparency (EIT)-like cooling mechanism in a double-cavity optomechanical system, where an additional cavity couples to the original one in the standard optomechanical system. By choosing optimal parameters such that the cooling process of the mechanical resonator corresponds to the maximum value of the optical fluctuation spectrum and the heating process to the minimum one, the mechanical resonator can be cooled with the final mean phonon number less than that at the absence of the additional cavity. And we show the mechanical resonator may be cooled close to its ground state via such an EIT-like cooling mechanism even when the original resolved sideband condition is not fulfilled.

  18. Electromagnetically-induced-transparency ground-state cooling of long ion strings

    NASA Astrophysics Data System (ADS)

    Lechner, Regina; Maier, Christine; Hempel, Cornelius; Jurcevic, Petar; Lanyon, Ben P.; Monz, Thomas; Brownnutt, Michael; Blatt, Rainer; Roos, Christian F.

    2016-05-01

    Electromagnetically-induced-transparency (EIT) cooling is a ground-state cooling technique for trapped particles. EIT offers a broader cooling range in frequency space compared to more established methods. In this work, we experimentally investigate EIT cooling in strings of trapped atomic ions. In strings of up to 18 ions, we demonstrate simultaneous ground-state cooling of all radial modes in under 1 ms. This is a particularly important capability in view of emerging quantum simulation experiments with large numbers of trapped ions. Our analysis of the EIT cooling dynamics is based on a technique enabling single-shot measurements of phonon numbers, by rapid adiabatic passage on a vibrational sideband of a narrow transition.

  19. Controlled cooling of an electronic system based on projected conditions

    SciTech Connect

    David, Milnes P.; Iyengar, Madhusudan K.; Schmidt, Roger R.

    2015-08-18

    Energy efficient control of a cooling system cooling an electronic system is provided based, in part, on projected conditions. The control includes automatically determining an adjusted control setting(s) for an adjustable cooling component(s) of the cooling system. The automatically determining is based, at least in part, on projected power consumed by the electronic system at a future time and projected temperature at the future time of a heat sink to which heat extracted is rejected. The automatically determining operates to reduce power consumption of the cooling system and/or the electronic system while ensuring that at least one targeted temperature associated with the cooling system or the electronic system is within a desired range. The automatically determining may be based, at least in part, on an experimentally obtained model(s) relating the targeted temperature and power consumption of the adjustable cooling component(s) of the cooling system.

  20. A GPU Accelerated Simulation Program for Electron Cooling Process

    NASA Astrophysics Data System (ADS)

    Zhang, He; Huang, He; Li, Rui; Chen, Jie; Luo, Li-Shi

    2015-04-01

    Electron cooling is essential to achieve high luminosity in the medium energy electron ion collider (MIEC) project at Jefferson Lab. Bunched electron beam with energy above 50 MeV is used to cool coasting and/or bunched ion beams. Although the conventional electron cooling technique has been widely used, such an implementation in MEIC is still challenging. We are developing a simulation program for the electron cooling process to fulfill the need of the electron cooling system design for MEIC. The program simulates the evolution of the ion beam under the intrabeam scattering (IBS) effect and the electron cooling effect using Monte Carlo method. To accelerate the calculation, the program is developed on a GPU platform. We will present some preliminary simulation results. Work supported by the Department of Energy, Laboratory Directed Research and Development Funding, under Contract No. DE-AC05-06OR23177.

  1. ELECTRON COOLING AND ELECTRON-ION COLLIDERS AT BNL.

    SciTech Connect

    BEN-ZVI,I.

    2007-10-03

    Superconducting Energy Recovery Linacs (ERL) have significant potential uses in various fields, including High Energy Physics and Nuclear Physics. Brookhaven National Laboratory (BNL) is pursuing some of the potential applications in this area and the technology issues that are associated with these applications. The work addressed in this paper is carried out at BNL towards applications in electron cooling of high-energy hadron beams and electron-nucleon colliders. The common issues for these applications are the generation of high currents of polarized or high-brightness unpolarized electrons, high-charge per bunch and high-current. One must address the associated issue of High-Order Modes generation and damping. Superconducting ERLs have great advantages for these applications as will be outlined in the text.

  2. Cooling systems and hybrid A/C systems using an electromagnetic radiation-absorbing complex

    SciTech Connect

    Halas, Nancy J.; Nordlander, Peter; Neumann, Oara

    2015-05-19

    A method for powering a cooling unit. The method including applying electromagnetic (EM) radiation to a complex, where the complex absorbs the EM radiation to generate heat, transforming, using the heat generated by the complex, a fluid to vapor, and sending the vapor from the vessel to a turbine coupled to a generator by a shaft, where the vapor causes the turbine to rotate, which turns the shaft and causes the generator to generate the electric power, wherein the electric powers supplements the power needed to power the cooling unit

  3. Field measurements in the Fermilab electron cooling solenoid prototype

    SciTech Connect

    A. C. Crawford et al.

    2003-10-02

    To increase the Tevatron luminosity, Fermilab is developing a high-energy electron cooling system [1] to cool 8.9-GeV/c antiprotons in the Recycler ring. The schematic layout of the Recycler Electron Cooling (REC) system is shown in Figure 1. Cooling of antiprotons requires a round electron beam with a small angular spread propagating through a cooling section with a kinetic energy of 4.3 MeV. To confine the electron beam tightly and to keep its transverse angles below 10{sup -4} rad, the cooling section will be immersed into a solenoidal field of 50-150G. As part of the R&D effort, a cooling section prototype consisting of 9 modules (90% of the total length of a future section) was assembled and measured. This paper describes the technique of measuring and adjusting the magnetic field quality in the cooling section and presents preliminary results of solenoid prototype field measurements. The design of the cooling section solenoid is discussed in Chapter 2. Chapter 3 describes details of a dedicated measurement system, capable of measuring small transverse field components, while the system's measurement errors are analyzed in Chapter 4. Chapter 5 contains measured field distributions of individual elements of the cooling section as well as an evaluation of the magnetic shielding efficiency. An algorithm of field adjustments for providing lowest possible electron trajectory perturbations is proposed in Chapter 6; also, this chapter shows the results of our first attempts of implementing the algorithm.

  4. Electron beam injection during active experiments. I - Electromagnetic wave emissions

    NASA Technical Reports Server (NTRS)

    Winglee, R. M.; Kellogg, P. J.

    1990-01-01

    The wave emissions produced in Echo 7 experiment by active injections of electron beams were investigated to determine the properties of the electromagnetic and electrostatic fields for both the field-aligned and cross-field injection in such experiments and to evaluate the sources of free energy and relative efficiencies for the generation of the VLF and HF emissions. It is shown that, for typical beam energies in active experiments, electromagnetic effects do not substantially change the bulk properties of the beam, spacecraft charging, and plasma particle acceleration. Through simulations, beam-generated whistlers; fundamental z-mode and harmonic x-mode radiation; and electrostatic electron-cyclotron, upper-hybrid, Langmuir, and lower-hybrid waves were identified. The characteristics of the observed wave spectra were found to be sensitive to both the ratio of the electron plasma frequency to the cyclotron frequency and the angle of injection relative to the magnetic field.

  5. Control of electronic transport in graphene by electromagnetic dressing.

    PubMed

    Kristinsson, K; Kibis, O V; Morina, S; Shelykh, I A

    2016-01-01

    We demonstrated theoretically that the renormalization of the electron energy spectrum near the Dirac point of graphene by a strong high-frequency electromagnetic field (dressing field) drastically depends on polarization of the field. Namely, linear polarization results in an anisotropic gapless energy spectrum, whereas circular polarization leads to an isotropic gapped one. As a consequence, the stationary (dc) electronic transport in graphene strongly depends on parameters of the dressing field: A circularly polarized field monotonically decreases the isotropic conductivity of graphene, whereas a linearly polarized one results in both giant anisotropy of conductivity (which can reach thousands of percents) and the oscillating behavior of the conductivity as a function of the field intensity. Since the predicted phenomena can be observed in a graphene layer irradiated by a monochromatic electromagnetic wave, the elaborated theory opens a substantially new way to control electronic properties of graphene with light. PMID:26838371

  6. Relativistic electromagnetic waves in an electron-ion plasma

    NASA Technical Reports Server (NTRS)

    Chian, Abraham C.-L.; Kennel, Charles F.

    1987-01-01

    High power laser beams can drive plasma particles to relativistic energies. An accurate description of strong waves requires the inclusion of ion dynamics in the analysis. The equations governing the propagation of relativistic electromagnetic waves in a cold electron-ion plasma can be reduced to two equations expressing conservation of energy-momentum of the system. The two conservation constants are functions of the plasma stream velocity, the wave velocity, the wave amplitude, and the electron-ion mass ratio. The dynamic parameter, expressing electron-ion momentum conversation in the laboratory frame, can be regarded as an adjustable quantity, a suitable choice of which will yield self-consistent solutions when other plasma parameters were specified. Circularly polarized electromagnetic waves and electrostatic plasma waves are used as illustrations.

  7. Control of electronic transport in graphene by electromagnetic dressing

    PubMed Central

    Kristinsson, K.; Kibis, O. V.; Morina, S.; Shelykh, I. A.

    2016-01-01

    We demonstrated theoretically that the renormalization of the electron energy spectrum near the Dirac point of graphene by a strong high-frequency electromagnetic field (dressing field) drastically depends on polarization of the field. Namely, linear polarization results in an anisotropic gapless energy spectrum, whereas circular polarization leads to an isotropic gapped one. As a consequence, the stationary (dc) electronic transport in graphene strongly depends on parameters of the dressing field: A circularly polarized field monotonically decreases the isotropic conductivity of graphene, whereas a linearly polarized one results in both giant anisotropy of conductivity (which can reach thousands of percents) and the oscillating behavior of the conductivity as a function of the field intensity. Since the predicted phenomena can be observed in a graphene layer irradiated by a monochromatic electromagnetic wave, the elaborated theory opens a substantially new way to control electronic properties of graphene with light. PMID:26838371

  8. Control of electronic transport in graphene by electromagnetic dressing

    NASA Astrophysics Data System (ADS)

    Kristinsson, K.; Kibis, O. V.; Morina, S.; Shelykh, I. A.

    2016-02-01

    We demonstrated theoretically that the renormalization of the electron energy spectrum near the Dirac point of graphene by a strong high-frequency electromagnetic field (dressing field) drastically depends on polarization of the field. Namely, linear polarization results in an anisotropic gapless energy spectrum, whereas circular polarization leads to an isotropic gapped one. As a consequence, the stationary (dc) electronic transport in graphene strongly depends on parameters of the dressing field: A circularly polarized field monotonically decreases the isotropic conductivity of graphene, whereas a linearly polarized one results in both giant anisotropy of conductivity (which can reach thousands of percents) and the oscillating behavior of the conductivity as a function of the field intensity. Since the predicted phenomena can be observed in a graphene layer irradiated by a monochromatic electromagnetic wave, the elaborated theory opens a substantially new way to control electronic properties of graphene with light.

  9. Emittance Reduction between EBIS LINAC and Booster by Electron Beam Cooling; Is Single Pass Cooling Possible?

    SciTech Connect

    Hershcovitch,A.

    2008-04-01

    Electron beam cooling is examined as an option to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster. Electron beam parameters are based on experimental data (obtained at BNL) of electron beams extracted from a plasma cathode. Preliminary calculations indicate that single pass cooling is feasible; momentum spread can be reduced by more than an order of magnitude in less than one meter.

  10. PROGRESS OF HIGH-ENERGY ELECTRON COOLING FOR RHIC.

    SciTech Connect

    FEDOTOV,A.V.

    2007-09-10

    The fundamental questions about QCD which can be directly answered at Relativistic Heavy Ion Collider (RHIC) call for large integrated luminosities. The major goal of RHIC-I1 upgrade is to achieve a 10 fold increase in luminosity of Au ions at the top energy of 100 GeV/nucleon. Such a boost in luminosity for RHIC-II is achievable with implementation of high-energy electron cooling. The design of the higher-energy cooler for RHIC-II recently adopted a non-magnetized approach which requires a low temperature electron beam. Such electron beams will be produced with a superconducting Energy Recovery Linac (ERL). Detailed simulations of the electron cooling process and numerical simulations of the electron beam transport including the cooling section were performed. An intensive R&D of various elements of the design is presently underway. Here, we summarize progress in these electron cooling efforts.

  11. Attractors and chaos of electron dynamics in electromagnetic standing waves

    NASA Astrophysics Data System (ADS)

    Esirkepov, Timur Zh.; Bulanov, Stepan S.; Koga, James K.; Kando, Masaki; Kondo, Kiminori; Rosanov, Nikolay N.; Korn, Georg; Bulanov, Sergei V.

    2015-09-01

    In an electromagnetic standing wave formed by two super-intense colliding laser pulses, radiation reaction totally modifies the electron motion. The quantum corrections to the electron motion and the radiation reaction force can be independently small or large, depending on the laser intensity and wavelength, thus dividing the parameter space into 4 domains. The electron motion evolves to limit cycles and strange attractors when radiation reaction dominates. This creates a new framework for high energy physics experiments on the interaction of energetic charged particle beams and colliding super-intense laser pulses.

  12. Kinetics of electron cooling of positrons in a storage ring

    SciTech Connect

    Men'shikov, L. I.

    2008-06-15

    Kinetic equations are derived for the positron velocity distribution in storage rings with electron cooling. Both drag force and components of the velocity diffusion tensor are calculated. The mechanism of approach to a steady-state positron velocity distribution via electron cooling is discussed. It is shown that the resulting steady-state positron distribution is very close to the electron distribution when the magnetic field is sufficiently strong.

  13. Advanced cooling techniques for FASTBUS electronics

    SciTech Connect

    Chato, J.C.; Golliher, E.L.; Downing, R.W.

    1986-02-01

    A multi-phase research and development effort has been conducted to explore improved cooling techniques for the FASTBUS system. The research was supported by the Fermi National Accelerator Laboratory. Some of the relevant, major requirements and limits of this system are: 1. The cooling system should not significantly interfere with the rapid handling of the cards; 2. The die temperatures of the integrated circuits should not exceed 85/sup 0/C; 3. The temperature differential between the dies of emitter coupled logic (ECL) circuits that connect directly to each other should not exceed 30/sup 0/C; 4. The temperature differential of the cooling air between any two points in the module should not exceed 20/sup 0/C; 5. In air cooled modules, the air temperature should not exceed 60/sup 0/C anywhere; and 6. The noise emanating from the computer should be at a tolerable level. The first requirement, together with some related considerations, virtually excludes any direct liquid cooling schemes. Thus heat removal from the chips themselves can be achieved either by convection to air or by a heat conducting structure which transfers the heat to the coolant used. The second through fourth requirements are generally rigorous. However, the fifth is for plastic encased microchips (CA3083 16-pin, high current transistor, dual in-line package) and can be relaxed for other types with lower internal thermal resistances. Our work can be divided into three parts. The first dealt with the development of an air cooled system based on the state-of-the-art of commercially available technology. The second explored various air cooling techniques and the third, examined methods where the heat from the chips was conducted to water cooled plates located parallel to the chip carrying cards.

  14. Electron cooling for low-energy RHIC program

    SciTech Connect

    Fedotov, A.; Ben-Zvi, I.; Chang, X.; Kayran, D.; Litvinenko, V.N.; Pendzick, A.; Satogata, T.

    2009-08-31

    Electron cooling was proposed to increase luminosity of the RHIC collider for heavy ion beam energies below 10 GeV/nucleon. Providing collisions at such energies, termed RHIC 'low-energy' operation, will help to answer one of the key questions in the field of QCD about existence and location of critical point on the QCD phase diagram. The electron cooling system should deliver electron beam of required good quality over energies of 0.9-5 MeV. Several approaches to provide such cooling were considered. The baseline approach was chosen and design work started. Here we describe the main features of the cooling system and its expected performance. We have started design work on a low-energy RHIC electron cooler which will operate with kinetic electron energy range 0.86-2.8 (4.9) MeV. Several approaches to an electron cooling system in this energy range are being investigated. At present, our preferred scheme is to transfer the Fermilab Pelletron to BNL after Tevatron shutdown, and to use it for DC non-magnetized cooling in RHIC. Such electron cooling system can significantly increase RHIC luminosities at low-energy operation.

  15. Electron Cooling of Ions and Antiprotons in Traps

    SciTech Connect

    Zwicknagel, Guenter

    2006-03-20

    For a theoretical description of electron cooling of ions or antiprotons in traps we have investigated the energy loss and cooling force in a strongly magnetized electron plasma employing both perturbation approaches and more complete numerical simulations. Some characteristic features for cooling under conditions prevailing in Penning traps are presented. One particular feature is, that the energy loss in strongly magnetized electrons, which tend to move along the field lines like beads on a wire, strongly depends on the sign of the interaction. The energy loss can be significantly larger for antiprotons than for protons. Special attention is paid to the cooling of highly charged ions, here bare Uranium, in HITRAP. The time evolution of the energy distribution of the trapped ions is studied within a simplified model which takes into account the related heating of the electrons. The feedback of this heating on the energy loss results in an intricate dependency of the cooling times on the density of the electrons and the ratio of the number of ions to the number of electrons in the trap. From this analysis we find that cooling times less than about a second are feasible for electron cooling of bare Uranium in HITRAP.

  16. Atom-membrane cooling and entanglement using cavity electromagnetically induced transparency

    SciTech Connect

    Genes, Claudiu; Ritsch, Helmut; Drewsen, Michael; Dantan, Aurelien

    2011-11-15

    We investigate a hybrid optomechanical system composed of a micromechanical oscillator as a movable membrane and an atomic three-level ensemble within an optical cavity. We show that a suitably tailored cavity field response via electromagnetically induced transparency (EIT) in the atomic medium allows for strong coupling of the membrane's mechanical oscillations to the collective atomic ground-state spin. This facilitates ground-state cooling of the membrane motion, quantum state mapping, and robust atom-membrane entanglement even for cavity widths larger than the mechanical resonance frequency.

  17. Electromagnetic solitons in degenerate relativistic electron-positron plasma

    NASA Astrophysics Data System (ADS)

    Berezhiani, V. I.; Shatashvili, N. L.; Tsintsadze, N. L.

    2015-06-01

    The existence of soliton-like electromagnetic (EM) distributions in a fully degenerate electron-positron plasma is studied applying relativistic hydrodynamic and Maxwell equations. For a circularly polarized wave it is found that the soliton solutions exist both in relativistic as well as nonrelativistic degenerate plasmas. Plasma density in the region of soliton pulse localization is reduced considerably. The possibility of plasma cavitation is also shown.

  18. Modeling Evaporative Electron Cooling in an Ultracold Neutral Plasma

    NASA Astrophysics Data System (ADS)

    Witte, Craig; Roberts, Jacob

    2015-11-01

    Ultracold plasmas (UCPs) are formed by photoionizing a collection of laser cooled atoms. Once formed, these plasmas expand, cooling over the course of their expansion. In theory, further cooling should be obtainable by forcibly inducing electron evaporation by applying DC electric fields to extract electrons. However, this cooling is difficult to quantify experimentally. Any attempt to obtain such a measurement requires a firm knowledge of evaporation dynamics in the system. For UCPs, electron mean free paths are smaller than the width of the plasma, resulting in significant transport effects that are not included in standard evaporation treatments. We have developed a simple Monte Carlo model that incorporates these effects. This talk will discuss this model, and how it can be utilized to measure evaporation and cooling in UCPs. This work was supported by the Air Force Office of Scientific Research.

  19. Cooling of hot electrons in amorphous silicon

    SciTech Connect

    Vanderhaghen, R.; Hulin, D.; Cuzeau, S.; White, J.O.

    1997-07-01

    Measurements of the cooling rate of hot carriers in amorphous silicon are made with a two-pump, one-probe technique. The experiment is simulated with a rate-equation model describing the energy transfer between a population of hot carriers and the lattice. An energy transfer rate proportional to the temperature difference is found to be consistent with the experimental data while an energy transfer independent of the temperature difference is not. This contrasts with the situation in crystalline silicon. The measured cooling rates are sufficient to explain the difficulty in observing avalanche effects in amorphous silicon.

  20. Self-Consistent Electromagnetic Modeling of Electron Sources

    SciTech Connect

    Hess, Mark

    2006-11-27

    The modeling of high-brightness electron sources, such as photoinjectors, requires a self-consistent technique for including the electromagnetics of tight electron bunches, as well as, the appropriate conductor boundary conditions of the source. A novel and effective technique for incorporating both of these effects utilizes time-dependent Green's functions. The advantages of this method are that Green's functions are generated by Delta function sources (making them ideal for tight bunch modeling) while simultaneously satisfying the conductor boundary condition. We demonstrate how these methods are used in a newly developed code called IRPSS (Indiana Rf Photocathode Source Simulator), and show initial simulations using IRPSS.

  1. Cooling force on ions in a magnetized electron plasma

    NASA Astrophysics Data System (ADS)

    Nersisyan, Hrachya B.; Zwicknagel, Günter

    2013-07-01

    Electron cooling is a well-established method to improve the phase space quality of ion beams in storage rings. In the common rest frame of the ion and the electron beam, the ion is subjected to a drag force and it experiences a loss or a gain of energy which eventually reduces the energy spread of the ion beam. A calculation of this process is complicated as the electron velocity distribution is anisotropic and the cooling process takes place in a magnetic field which guides the electrons. In this paper the cooling force is calculated in a model of binary collisions (BC) between ions and magnetized electrons, in which the Coulomb interaction is treated up to second order as a perturbation to the helical motion of the electrons. The calculations are done with the help of an improved BC theory which is uniformly valid for any strength of the magnetic field and where the second-order two-body forces are treated in the interaction in Fourier space without specifying the interaction potential. The cooling force is explicitly calculated for a regularized and screened potential which is both of finite range and less singular than the Coulomb interaction at the origin. Closed expressions are derived for monochromatic electron beams, which are folded with the velocity distributions of the electrons and ions. The resulting cooling force is evaluated for anisotropic Maxwell velocity distributions of the electrons and ions.

  2. Use of an Electron Beam for Stochastic Cooling

    SciTech Connect

    Yaroslave Derbenev

    2007-09-10

    Microwave instability of an electron beam can be used for a multiple increase in the collective response for the perturbation caused by a particle of a co-moving ion beam, i.e. for enhancement of friction force in electron cooling method. The low scale (hundreds GHz and higher frequency range) space charge or FEL type instabilities can be produced (depending on conditions) by introducing an alternating magnetic fields along the electron beam path. Beams’ optics and noise conditioning for obtaining a maximal cooling effect and related limitations will be discussed. The method promises to increase by a few orders of magnitude the cooling rate for heavy particle beams with a large emittance for a wide energy range with respect to either electron and conventional stochastic cooling.

  3. Progress on Analytical Modeling of Coherent Electron Cooling

    SciTech Connect

    Wang, G.; Blaskiewicz, M.; Litvinenko, V.; Webb, S.

    2010-05-23

    We report recent progresses on analytical studies of Coherent Electron Cooling. The phase space electron beam distribution obtained from the 1D FEL amplifier is applied to an infinite electron plasma model and the electron density evolution inside the kicker is derived. We also investigate the velocity modulation in the modulator and obtain a closed form solution for the current density evolution for infinite homogeneous electron plasma.

  4. The integration of cryogenic cooling systems with superconducting electronic systems

    SciTech Connect

    Green, Michael A.

    2003-07-01

    The need for cryogenic cooling has been critical issue that has kept superconducting electronic devices from reaching the market place. Even though the performance of the superconducting circuit is superior to silicon electronics, the requirement for cryogenic cooling has put the superconducting devices at a disadvantage. This report will talk about the various methods for refrigerating superconducting devices. Cryocooler types will be compared for vibration, efficiency, and cost. Some solutions to specific problems of integrating cryocoolers to superconducting devices are presented.

  5. HIGH-CURRENT ERL-BASED ELECTRON COOLING FOR RHIC.

    SciTech Connect

    BEN-ZVI, I.

    2005-09-18

    The design of an electron cooler must take into account both electron beam dynamics issues as well as the electron cooling physics. Research towards high-energy electron cooling of RHIC is in its 3rd year at Brookhaven National Laboratory. The luminosity upgrade of RHIC calls for electron cooling of various stored ion beams, such as 100 GeV/A gold ions at collision energies. The necessary electron energy of 54 MeV is clearly out of reach for DC accelerator system of any kind. The high energy also necessitates a bunched beam, with a high electron bunch charge, low emittance and small energy spread. The Collider-Accelerator Department adopted the Energy Recovery Linac (ERL) for generating the high-current, high-energy and high-quality electron beam. The RHIC electron cooler ERL will use four Superconducting RF (SRF) 5-cell cavities, designed to operate at ampere-class average currents with high bunch charges. The electron source will be a superconducting, 705.75 MHz laser-photocathode RF gun, followed up by a superconducting Energy Recovery Linac (ERL). An R&D ERL is under construction to demonstrate the ERL at the unprecedented average current of 0.5 amperes. Beam dynamics performance and luminosity enhancement are described for the case of magnetized and non-magnetized electron cooling of RHIC.

  6. Feasibility of electron cooling and luminosity potentials of colliders

    SciTech Connect

    Yaroslav Derbenev

    2004-07-02

    Luminosity upgrades of colliders with hadron beams tend to require decreased and maintained beam emittances using a suitable cooling technique. The breakthroughs of recent years: realization of beam energy recovery in superconducting linear accelerators; flat to round beam transformations; and new beam transport concepts (discontinuous solenoid, circulator rings, hollow beams, dispersive cooling); have promoted the feasibility of efficient electron cooling of intense high energy hadron beams. Electron cooling, in cooperation with strong SRF fields in storage rings, will allow one to obtain very short hadron bunches, as result of which the luminosity can be raised by making a low beta-star. Short bunches also would make feasible crab crossing, that allows one to remove the parasitic beam-beam interactions and maximize the collision rate. Cooling also results in flatness of uncoupled beam equilibrium; this can be used to diminish the IBS impact on luminosity.

  7. Hole Cooling Is Much Faster than Electron Cooling in PbSe Quantum Dots.

    PubMed

    Spoor, Frank C M; Kunneman, Lucas T; Evers, Wiel H; Renaud, Nicolas; Grozema, Ferdinand C; Houtepen, Arjan J; Siebbeles, Laurens D A

    2016-01-26

    In semiconductor quantum dots (QDs), charge carrier cooling is in direct competition with processes such as carrier multiplication or hot charge extraction that may improve the light conversion efficiency of photovoltaic devices. Understanding charge carrier cooling is therefore of great interest. We investigate high-energy optical transitions in PbSe QDs using hyperspectral transient absorption spectroscopy. We observe bleaching of optical transitions involving higher valence and conduction bands upon band edge excitation. The kinetics of rise of the bleach of these transitions after a pump laser pulse allow us to monitor, for the first time, cooling of hot electrons and hot holes separately. Our results show that holes cool significantly faster than electrons in PbSe QDs. This is in contrast to the common assumption that electrons and holes behave similarly in Pb chalcogenide QDs and has important implications for the utilization of hot charge carriers in photovoltaic devices. PMID:26654878

  8. Testing aspects of advanced coherent electron cooling technique

    SciTech Connect

    Litvinenko, V.; Jing, Y.; Pinayev, I.; Wang, G.; Samulyak, R.; Ratner, D.

    2015-05-03

    An advanced version of the Coherent-electron Cooling (CeC) based on the micro-bunching instability was proposed. This approach promises significant increase in the bandwidth of the CeC system and, therefore, significant shortening of cooling time in high-energy hadron colliders. In this paper we present our plans of simulating and testing the key aspects of this proposed technique using the set-up of the coherent-electron-cooling proof-of-principle experiment at BNL.

  9. Coherent electron cooling proof of principle instrumentation design

    SciTech Connect

    Gassner D. M.; Litvinenko, V.; Michnoff, R.; Miller, T.; Minty, M.; Pinayev, I.

    2012-04-15

    The goal of the Coherent Electron Cooling Proof-of-Principle (CeC PoP) experiment being designed at RHIC is to demonstrate longitudinal (energy spread) cooling before the expected CD-2 for eRHIC. The scope of the experiment is to longitudinally cool a single bunch of 40 GeV/u gold ions in RHIC. This paper will describe the instrumentation systems proposed to meet the diagnostics challenges. These include measurements of beam intensity, emittance, energy spread, bunch length, position, orbit stability, and transverse and temporal alignment of electron and ion beams.

  10. Longitudinal electron cooling experiments at HIRFL-CSRe

    NASA Astrophysics Data System (ADS)

    Mao, L. J.; Zhao, H.; Yang, X. D.; Li, J.; Yang, J. C.; Yuan, Y. J.; Parkhomchuk, V. V.; Reva, V. B.; Ma, X. M.; Yan, T. L.; Tang, M. T.; Xia, J. W.

    2016-02-01

    At the heavy ion storage ring HIRFL-CSRe an electron cooler is operated to improve the beam conditions for experiments. The properties of cooled beams have been studied. The longitudinal beam dynamics during the cooling process was measured by a resonant Schottky detector. The dependencies of the parameters electron beam density and profile on cooling times were investigated. The friction force was measured directly with the aid of the high voltage system of the cooler and with the application of the beam bunching system as well. An experiment with bunched cold beam showed a dependence of the bunch length on the beam density.

  11. Emerging Two-Phase Cooling Technologies for Power Electronic Inverters

    SciTech Connect

    Hsu, J.S.

    2005-08-17

    In order to meet the Department of Energy's (DOE's) FreedomCAR and Vehicle Technologies (FVCT) goals for volume, weight, efficiency, reliability, and cost, the cooling of the power electronic devices, traction motors, and generators is critical. Currently the power electronic devices, traction motors, and generators in a hybrid electric vehicle (HEV) are primarily cooled by water-ethylene glycol (WEG) mixture. The cooling fluid operates as a single-phase coolant as the liquid phase of the WEG does not change to its vapor phase during the cooling process. In these single-phase systems, two cooling loops of WEG produce a low temperature (around 70 C) cooling loop for the power electronics and motor/generator, and higher temperature loop (around 105 C) for the internal combustion engine. There is another coolant option currently available in automobiles. It is possible to use the transmission oil as a coolant. The oil temperature exists at approximately 85 C which can be utilized to cool the power electronic and electrical devices. Because heat flux is proportional to the temperature difference between the device's hot surface and the coolant, a device that can tolerate higher temperatures enables the device to be smaller while dissipating the same amount of heat. Presently, new silicon carbide (SiC) devices and high temperature direct current (dc)-link capacitors, such as Teflon capacitors, are available but at significantly higher costs. Higher junction temperature (175 C) silicon (Si) dies are gradually emerging in the market, which will eventually help to lower hardware costs for cooling. The development of high-temperature devices is not the only way to reduce device size. Two-phase cooling that utilizes the vaporization of the liquid to dissipate heat is expected to be a very effective cooling method. Among two-phase cooling methods, different technologies such as spray, jet impingement, pool boiling and submersion, etc. are being developed. The Oak Ridge National Laboratory (ORNL) is leading the research on a novel floating refrigerant loop that cools high-power electronic devices and the motor/generator with very low cooling energy. The loop can be operated independently or attached to the air conditioning system of the vehicle to share the condenser and other mutually needed components. The ability to achieve low cooling energy in the floating loop is attributable to the liquid refrigerant operating at its hot saturated temperature (around 50 C+). In an air conditioning system, the liquid refrigerant is sub-cooled for producing cool air to the passenger compartment. The ORNL floating loop avoids the sub-cooling of the liquid refrigerant and saves significant cooling energy. It can raise the coefficient of performance (COP) more than 10 fold from that of the existing air-conditioning system, where the COP is the ratio of the cooled power and the input power for dissipating the cooled power. In order to thoroughly investigate emerging two-phase cooling technologies, ORNL subcontracted three university/companies to look into three leading two-phase cooling technologies. ORNL's assessments on these technologies are summarized in Section I. Detailed descriptions of the reports by the three university/companies (subcontractors) are in Section II.

  12. Effects of e-beam parameters on coherent electron cooling

    SciTech Connect

    Webb, S.D.; Litvinenko, V.N.; Wang, G.

    2011-03-28

    Coherent Electron Cooling (CeC) requires detailed control of the phase between the hadron an the FEL-amplified wave packet. This phase depends on local electron beam parameters such as the energy spread and the peak current. In this paper, we examine the effects of local density variations on the cooling rates for CeC. Coherent Electron Cooling (CeC) [1] is a new concept in intense, high energy hadron beamcooling, in which the Debye screened charge perturbation calculated in [2] is used to seed a high-gain free electron laser (FEL). Using delays to give the perturbing hadron an energy-dependent longitudinal displacement relative to its frequencymodulated charge perturbation, the hadron receives an energy-dependent kick which reduces its energy variation from the design energy. The equations of motion in [1] assume that the electron bunch is the same physical size as the hadron bunch, and has a homogeneous charge density across the entire bunch. In practice, the electron bunches will be much shorter than the hadron bunch, and this local spacial inhomogeneity in the charge distribution will alter the gain length of the FEL, resulting in both a change in the amplification of the initial signal and a phase shift. In this paper we consider these inhomogeneity effects, determining cooling equations for bunched beam CeC consistent with these effects and determining thresholds for the cooling parameters.

  13. ELECTRON COOLING IN THE PRESENCE OF UNDULATOR FIELDS

    SciTech Connect

    FEDOTOV,A.; BEN-ZVI, I.; ET AL.

    2007-06-25

    The design of the higher-energy cooler for Relativistic Heavy Ion Collider (RHIC) recently adopted a non-magnetized approach which requires a low temperature electron beam. However, to avoid significant loss of heavy ions due to recombination with electrons in the cooling section, the temperature of the electron beam should be high. These two contradictory requirements are satisfied in the design of the RWIC cooler with the help of the undulator fields. The model of the friction force in the presence of an undulator field was benchmarked vs. direct numerical simulations with an excellent agreement. Here, we discuss cooling dynamics simulations with a helical undulator, including recombination suppression and resulting luminosities.

  14. Direct electronic measurement of Peltier cooling and heating in graphene.

    PubMed

    Vera-Marun, I J; van den Berg, J J; Dejene, F K; van Wees, B J

    2016-01-01

    Thermoelectric effects allow the generation of electrical power from waste heat and the electrical control of cooling and heating. Remarkably, these effects are also highly sensitive to the asymmetry in the density of states around the Fermi energy and can therefore be exploited as probes of distortions in the electronic structure at the nanoscale. Here we consider two-dimensional graphene as an excellent nanoscale carbon material for exploring the interaction between electronic and thermal transport phenomena, by presenting a direct and quantitative measurement of the Peltier component to electronic cooling and heating in graphene. Thanks to an architecture including nanoscale thermometers, we detected Peltier component modulation of up to 15 mK for currents of 20 μA at room temperature and observed a full reversal between Peltier cooling and heating for electron and hole regimes. This fundamental thermodynamic property is a complementary tool for the study of nanoscale thermoelectric transport in two-dimensional materials. PMID:27161186

  15. Direct electronic measurement of Peltier cooling and heating in graphene

    PubMed Central

    Vera-Marun, I. J.; van den Berg, J. J.; Dejene, F. K.; van Wees, B. J.

    2016-01-01

    Thermoelectric effects allow the generation of electrical power from waste heat and the electrical control of cooling and heating. Remarkably, these effects are also highly sensitive to the asymmetry in the density of states around the Fermi energy and can therefore be exploited as probes of distortions in the electronic structure at the nanoscale. Here we consider two-dimensional graphene as an excellent nanoscale carbon material for exploring the interaction between electronic and thermal transport phenomena, by presenting a direct and quantitative measurement of the Peltier component to electronic cooling and heating in graphene. Thanks to an architecture including nanoscale thermometers, we detected Peltier component modulation of up to 15 mK for currents of 20 μA at room temperature and observed a full reversal between Peltier cooling and heating for electron and hole regimes. This fundamental thermodynamic property is a complementary tool for the study of nanoscale thermoelectric transport in two-dimensional materials. PMID:27161186

  16. Prospects for Doppler cooling of three-electronic-level molecules

    SciTech Connect

    Nguyen, J. H. V.; Odom, B.

    2011-05-15

    Analogous to the extension of laser cooling techniques from two-level to three-level atoms, Doppler cooling of molecules with an intermediate electronic state is considered. In particular, we use a rate-equation approach to simulate cooling of SiO{sup +}, in which population buildup in the intermediate state is prevented by its short lifetime. We determine that Doppler cooling of SiO{sup +} can be accomplished without optically repumping from the intermediate state, at the cost of causing undesirable parity flips and rotational diffusion. Since the necessary repumping would require a large number of continuous-wave lasers, optical pulse shaping of a femtosecond laser is proposed as an attractive alternative. Other candidate three-electron-level molecules are also discussed.

  17. Mitigation of biofouling using electromagnetic fields in tubular heat exchangers-condensers cooled by seawater.

    PubMed

    Trueba, Alfredo; García, Sergio; Otero, Félix M

    2014-01-01

    Electromagnetic field (EMF) treatment is presented as an alternative physical treatment for the mitigation of biofouling adhered to the tubes of a heat exchanger-condenser cooled by seawater. During an experimental phase, a fouling biofilm was allowed to grow until experimental variables indicated that its growth had stabilised. Subsequently, EMF treatment was applied to seawater to eliminate the biofilm and to maintain the achieved cleanliness. The results showed that EMFs precipitated ions dissolved in the seawater. As a consequence of the application of EMFs, erosion altered the intermolecular bonding of extracellular polymers, causing the destruction of the biofilm matrix and its detachment from the inner surface of the heat exchanger-condenser tubes. This detachment led to the partial removal of a mature biofilm and a partial recovery of the efficiency lost in the heat transfer process by using a physical treatment that is harmless to the marine environment. PMID:24266611

  18. ELECTRON COOLING SIMULATIONS FOR LOW-ENERGY RHIC OPERATION.

    SciTech Connect

    FEDOTOV,A.V.; BEN-ZVI, I.; CHANG, X.; KAYRAN, D.; SATOGATA, T.

    2007-09-10

    Recently, a strong interest emerged in running the Relativistic Heavy Ion Collider (RHIC) at low beam total energies of 2.5-25 GeV/nucleon, substantially lower than the nominal beam total energy of 100 GeV/nucleon. Collisions in this low energy range are motivated by one of the key questions of quantum chromodynamics (QCD) about the existence and location of critical point on the QCD phase diagram. Applying electron cooling directly at these low energies in RHIC would result in significant luminosity increase and long beam stores for physics. Without direct cooling in RHIC at these low energies, beam lifetime and store times are very short, limited by strong transverse and longitudinal intrabeam scattering (IBS). In addition, for the lowest energies of the proposed energy scan, the longitudinal emittance of ions injected from the AGS into RHIC may be too big to fit into the RHIC RF bucket. An improvement in the longitudinal emittance of the ion beam can be provided by an electron cooling system at the AGS injection energy. Simulations of electron cooling both for direct cooling at low energies in RHIC and for injection energy cooling in the AGS were performed and are summarized in this report.

  19. Ultrarelativistic electron states in a general background electromagnetic field.

    PubMed

    Di Piazza, A

    2014-07-25

    The feasibility of obtaining exact analytical results in the realm of QED in the presence of a background electromagnetic field is almost exclusively limited to a few tractable cases, where the Dirac equation in the corresponding background field can be solved analytically. This circumstance has restricted, in particular, the theoretical analysis of QED processes in intense laser fields to within the plane wave approximation even at those high intensities, achievable experimentally only by tightly focusing the laser energy in space. Here, within the Wentzel-Kramers-Brillouin approximation, we construct analytically single-particle electron states in the presence of a background electromagnetic field of general space-time structure in the realistic assumption that the initial energy of the electron is the largest dynamical energy scale in the problem. The relatively compact expression of these states opens, in particular, the possibility of investigating analytically strong-field QED processes in the presence of spatially focused laser beams, which is of particular relevance in view of the upcoming experimental campaigns in this field. PMID:25105600

  20. ELECTRON HOLOGRAPHY OF ELECTROMAGNETIC FIELDS - RECENT THEORETICAL ADVANCES.

    SciTech Connect

    BELEGGIA,M.; POZZI, G.; TONOMURA, A.

    2007-01-01

    It has been shown in this work that the Fourier space approach can be fruitfully applied to the calculation of the fields and the associated electron optical phase shift of several magnetic and electrostatic structures, like superconducting vortices in conventional and high-T{sub c} superconductors, reverse biased p-n junctions, magnetic domains and nanoparticles. In all these cases, this novel approach has led to unexpected but extremely interesting results, very often expressed in analytical form, which allow the quantitative and reliable interpretation of the experimental data collected by means of electron holography or of more conventional Lorentz microscopy techniques. Moreover, it is worth recalling that whenever long-range electromagnetic fields are involved, a physical model of the object under investigation is necessary in order to take into account correctly the perturbation of the reference wave induced by the tail of the field protruding into the vacuum. For these reasons, we believe that the Fourier space approach for phase computations we have introduced and discussed in this chapter will represent an invaluable tool for the investigation of electromagnetic fields at the meso- and nano-scale.

  1. Resonance of relativistic electrons with electromagnetic ion cyclotron waves

    DOE PAGESBeta

    Denton, R. E.; Jordanova, V. K.; Bortnik, J.

    2015-06-29

    Relativistic electrons have been thought to more easily resonate with electromagnetic ion cyclotron EMIC waves if the total density is large. We show that, for a particular EMIC mode, this dependence is weak due to the dependence of the wave frequency and wave vector on the density. A significant increase in relativistic electron minimum resonant energy might occur for the H band EMIC mode only for small density, but no changes in parameters significantly decrease the minimum resonant energy from a nominal value. The minimum resonant energy depends most strongly on the thermal velocity associated with the field line motionmore » of the hot ring current protons that drive the instability. High density due to a plasmasphere or plasmaspheric plume could possibly lead to lower minimum resonance energy by causing the He band EMIC mode to be dominant. We demonstrate these points using parameters from a ring current simulation.« less

  2. Resonance of relativistic electrons with electromagnetic ion cyclotron waves

    SciTech Connect

    Denton, R. E.; Jordanova, V. K.; Bortnik, J.

    2015-06-29

    Relativistic electrons have been thought to more easily resonate with electromagnetic ion cyclotron EMIC waves if the total density is large. We show that, for a particular EMIC mode, this dependence is weak due to the dependence of the wave frequency and wave vector on the density. A significant increase in relativistic electron minimum resonant energy might occur for the H band EMIC mode only for small density, but no changes in parameters significantly decrease the minimum resonant energy from a nominal value. The minimum resonant energy depends most strongly on the thermal velocity associated with the field line motion of the hot ring current protons that drive the instability. High density due to a plasmasphere or plasmaspheric plume could possibly lead to lower minimum resonance energy by causing the He band EMIC mode to be dominant. We demonstrate these points using parameters from a ring current simulation.

  3. Electronics for a highly segmented electromagnetic calorimeter prototype

    NASA Astrophysics Data System (ADS)

    Fehlker, D.; Alme, J.; van den Brink, A.; de Haas, A. P.; Nooren, G.-J.; Reicher, M.; Röhrich, D.; Rossewij, M.; Ullaland, K.; Yang, S.

    2013-03-01

    A prototype of a highly segmented electromagnetic calorimeter has been developed. The detector tower is made of 24 layers of PHASE2/MIMOSA23 silicon sensors sandwiched between tungsten plates, with 4 sensors per layer, a total of 96 MIMOSA sensors, resulting in 39 MPixels for the complete prototype detector tower. The paper focuses on the electronics of this calorimeter prototype. Two detector readout and control systems are used, each containing two Spartan 6 and one Virtex 6 FPGA, running embedded Linux, each system serving 12 detector layers. In 550 ms a total of 4 Gbytes of data is read from the detector, stored in memory on the electronics and then shipped to the DAQ system via Gigabit ethernet.

  4. HIGH-ENERGY ELECTRON COOLING BASED ON REALISTIC SIX-DIMENSIONAL DISTRIBUTION OF ELECTRONS

    SciTech Connect

    FEDOTOV,A.; BEN-ZVI, I.; ET AL.

    2007-06-25

    The high-energy electron cooling system for RHIC-II is unique compared to standard coolers. It requires bunched electron beam. Electron bunches are produced by an Energy Recovery Linac (ERL), and cooling is planned without longitudinal magnetic field. To address unique features of the RHIC cooler, a generalized treatment of cooling force was introduced in BETACOOE code which allows us to calculate friction force for an arbitrary distribution of electrons. Simulations for RHIC cooler based on electron distribution from ERL are presented.

  5. Electron-phonon cooling in large monolayer graphene devices

    NASA Astrophysics Data System (ADS)

    McKitterick, Christopher B.; Prober, Daniel E.; Rooks, Michael J.

    2016-02-01

    We present thermal measurements of large-area (over 1000 μ m2 ) monolayer graphene samples at cryogenic temperatures to study the electron-phonon thermal conductivity of graphene. By using two large samples with areas which differ by a factor of 10, we are able to clearly show the area dependence of the electron-phonon cooling. We find that, at temperatures far below the Bloch-Grüneisen temperature TBG, the electron-phonon cooling power is accurately described by the T4 temperature dependence predicted for clean samples. Using this model, we are able to extract a value for the electron-phonon coupling constant as a function of gate voltage and the graphene electron-lattice deformation potential.

  6. Search for electron EDM with laser cooled radioactive atom

    NASA Astrophysics Data System (ADS)

    Inoue, T.; Arikawa, H.; Ezure, S.; Harada, K.; Hayamizu, T.; Ishikawa, T.; Itoh, M.; Kato, T.; Kawamura, H.; Nataraj, H. S.; Sato, T.; Aoki, T.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Shimizu, Y.; Wakasa, T.; Yoshida, H. P.; Sakemi, Y.

    2013-05-01

    The permanent electric dipole moment (EDM) of the elementary particle has the sensitivity to the CP violation in the theories beyond the standard model (SM). The search for the EDM constitutes the stringent test to discriminate between the SM and beyond it. We plan to perform the electron EDM search by using the laser cooled francium (Fr) atom which has the largest enhancement factor of the electron EDM in the alkali atoms. In this paper, the present status of the laser cooled Fr factory that is being constructed at Cyclotron and Radioisotope Center (CYRIC), Tohoku University are reported.

  7. Electron cooling in a young radio supernova: SN 2012aw

    SciTech Connect

    Yadav, Naveen; Ray, Alak; Chakraborti, Sayan; Stockdale, Christopher; Chandra, Poonam; Smith, Randall; Roy, Rupak; Bose, Subhash; Dwarkadas, Vikram; Sutaria, Firoza; Pooley, David E-mail: akr@tifr.res.in

    2014-02-10

    We present the radio observations and modeling of an optically bright Type II-P supernova (SN), SN 2012aw which exploded in the nearby galaxy Messier 95 (M95) at a distance of 10 Mpc. The spectral index values calculated using C, X, and K bands are smaller than the expected values for the optically thin regime. During this time, the optical bolometric light curve stays in the plateau phase. We interpret the low spectral-index values to be a result of electron cooling. On the basis of comparison between the Compton cooling timescale and the synchrotron cooling timescale, we find that the inverse Compton cooling process dominates over the synchrotron cooling process. We therefore model the radio emission as synchrotron emission from a relativistic electron population with a high energy cutoff. The cutoff is determined by comparing the electron cooling timescale, t {sub cool}, and the acceleration timescale, t-tilde {sub acc}. We constrain the mass-loss rate in the wind ( M-dot ∼1.9×10{sup −6} M{sub ⊙} yr{sup −1}) and the equipartition factor between relativistic electrons and the magnetic field ( α-tilde =ϵ{sub e}/ϵ{sub B}∼1.12×10{sup 2}) through our modeling of radio emission. Although the time of explosion is fairly well constrained by optical observations within about two days, we explore the effect of varying the time of explosion to best fit the radio light curves. The best fit is obtained for the explosion date as 2012 March 15.3 UT.

  8. Electron Cooling in a Young Radio Supernova: SN 2012aw

    NASA Astrophysics Data System (ADS)

    Yadav, Naveen; Ray, Alak; Chakraborti, Sayan; Stockdale, Christopher; Chandra, Poonam; Smith, Randall; Roy, Rupak; Bose, Subhash; Dwarkadas, Vikram; Sutaria, Firoza; Pooley, David

    2014-02-01

    We present the radio observations and modeling of an optically bright Type II-P supernova (SN), SN 2012aw which exploded in the nearby galaxy Messier 95 (M95) at a distance of 10 Mpc. The spectral index values calculated using C, X, and K bands are smaller than the expected values for the optically thin regime. During this time, the optical bolometric light curve stays in the plateau phase. We interpret the low spectral-index values to be a result of electron cooling. On the basis of comparison between the Compton cooling timescale and the synchrotron cooling timescale, we find that the inverse Compton cooling process dominates over the synchrotron cooling process. We therefore model the radio emission as synchrotron emission from a relativistic electron population with a high energy cutoff. The cutoff is determined by comparing the electron cooling timescale, t cool, and the acceleration timescale, \\tilde{t}_{acc}. We constrain the mass-loss rate in the wind (\\dot{M}\\sim 1.9\\times 10^{-6}\\ M_{\\odot }\\,yr^{-1}) and the equipartition factor between relativistic electrons and the magnetic field (\\tilde{\\alpha }=\\epsilon _e/\\epsilon _B\\sim 1.12\\times 10^2) through our modeling of radio emission. Although the time of explosion is fairly well constrained by optical observations within about two days, we explore the effect of varying the time of explosion to best fit the radio light curves. The best fit is obtained for the explosion date as 2012 March 15.3 UT.

  9. Low Frequency Electromagnetic Background Radiation From Electron Acceleration Above Thunderclouds

    NASA Astrophysics Data System (ADS)

    Fullekrug, Martin; Mezentsev, Andrew; Soula, Serge; van der Velde, Oscar; Farges, Thomas

    2013-04-01

    It was recently proposed that the acceleration of electrons during the growth and branching of streamers above thunderclouds initiated by intense lightning discharges could result in detectable low frequency electromagnetic radiation from several tens of kHz up to several hundreds of kHz (Qin et al., GRL, 2012). The intensity of the predicted radiation scales with the streamer density which is particularly large during spectacular sprite occurrences such as jellyfish sprites and/or dancing sprites. Dancing sprites are up to one second long sequences of consecutive sprites or sprite groups which are typically separated by some hundreds of milliseconds and which tend to follow the spatial development of large scale intracloud lightning discharges. A particularly spectacular series of 10 dancing sprite events over a Mediterranean mesoscale convective system was recorded with a low light video camera in south-eastern France during the early morning hours of August 31, 2012. Each dancing sprite event was composed of ~3-4 consecutive sprites or groups of sprites. All of these sprite occurrences were associated with a sudden enhancement ~2 uV/m/Hz-1/2 of the low frequency electromagnetic background radiation as measured with a radio receiver in south-west England. It is estimated that ~1000 streamers at a height of ~40 km are necessary to epxlain the observed electric field strengths. These sudden enhancements are superimposed on a more continuous low frequency electromagnetic background radiation which accompanies each dancing sprite event. It is speculated that this low frequency 'radio glow' results from filamentary streamers near the cloud top as a result of the large scale electrostatic charging of the thundercloud and that it may be used as an indicator for sprite occurrences in future studies.

  10. Passive Two-Phase Cooling of Automotive Power Electronics: Preprint

    SciTech Connect

    Moreno, G.; Jeffers, J. R.; Narumanchi, S.; Bennion, K.

    2014-08-01

    Experiments were conducted to evaluate the use of a passive two-phase cooling strategy as a means of cooling automotive power electronics. The proposed cooling approach utilizes an indirect cooling configuration to alleviate some reliability concerns and to allow the use of conventional power modules. An inverter-scale proof-of-concept cooling system was fabricated, and tests were conducted using the refrigerants hydrofluoroolefin HFO-1234yf and hydrofluorocarbon HFC-245fa. Results demonstrated that the system can dissipate at least 3.5 kW of heat with 250 cm3 of HFC-245fa. An advanced evaporator design that incorporates features to improve performance and reduce size was conceived. Simulation results indicate its thermal resistance can be 37% to 48% lower than automotive dual side cooled power modules. Tests were also conducted to measure the thermal performance of two air-cooled condensers--plain and rifled finned tube designs. The results combined with some analysis were then used to estimate the required condenser size per operating conditions and maximum allowable system (i.e., vapor and liquid) temperatures.

  11. Effect of magnetized electron cooling on a Hopf bifurcation

    SciTech Connect

    Lee, S.Y.; Ball, M.; Brabson, B.; Budnick, J.; Caussyn, D.D.; Colestock, P.; East, G.; Ellison, M.; Hamilton, B.; Hedblom, K.; Kang, X.; Li, D.; Liu, J.Y.; Ng, K.Y.; Pei, A.; Riabko, A.; Syphers, M.; Wang, L.

    1996-01-01

    We have observed longitudinal limit cycle oscillations of a proton beam when a critical threshold in the relative velocity between the proton beam and the cooling electrons has been exceeded. The threshold for the bifurcation of a fixed point into a limit cycle, also known as a Hopf bifurcation, was found to be asymmetric with respect to the relative velocity. Further experiments were performed to verify that the asymmetry was related to electron beam alignment with respect to the stored proton beam. The measured amplitudes of the ensuing limit cycle were used to determine the cooling drag force, which exhibits the essential characteristics of the magnetized cooling, where the limit cycle attractor can coexist with a damping-free region and/or a fixed point attractor. {copyright} {ital 1996 The American Physical Society.}

  12. Electromagnetic Fluctuations in Electron Non-thermal Plasmas (Invited)

    NASA Astrophysics Data System (ADS)

    Vinas, A. F.; Moya, P. S.; Navarro, R.; Araneda, J. A.

    2013-12-01

    Observed electron velocity distributions in the solar wind exhibit a variety of non-thermal features which deviate from thermal equilibrium, for example, in the form of temperature anisotropies, suprathermal tails, and field aligned beams. The state close to thermal equilibrium and its departure from it provides a source for spontaneous emissions of electromagnetic fluctuations as for example the whistler cyclotron waves. Here we present a comparative analysis of these fluctuations based upon anisotropic plasma modeled with Maxwellian and Tsalis kappa-like particle distributions. Dispersion analysis and stability thresholds are derived for these non-thermal distributions and compared with similar results obtained from PIC simulations using plasma and field parameters relevant to the solar wind environments.

  13. Electron diffusion in tokamaks due to electromagnetic fluctuations

    SciTech Connect

    Horton, W.; Choi, D.I.; Yushmanov, P.N.; Parail, V.V.

    1986-05-01

    Calculations for the stochastic diffusion of electrons in tokamaks due to a spectrum of electromagnetic drift fluctuations are presented. The parametric dependence of the diffusion coefficient on the amplitude and phase velocity of the spectrum, and the bounce frequency for the electrons is studied. The wavenumber spectrum is taken to be a low order (5 x 5) randomly-phased, isotropic, Monotonic spectrum extending from k /sub perpendicular min/ approx. = ..omega../sub ci//c/sub s/ to k/sub perpendicular max/ approx. = 3..omega../sub pe//c with different power laws of decrease phi k approx. = phi 1/k/sup m/, 1 less than or equal to m less than or equal to 3. A nonlinear Ohm's law is derived for the self-consistent relation between the electrostatic and parallel vector potentials. The parallel structure of the fluctuations is taken to be such that k parallel/sup nl/upsilon/sub e/ < w/sub k/ due to the nonlinear perpendicular motion of the electrons described in the nonlinear Ohm's law. The diffusion coefficient scales approximately as the neo-Alcator and Merezhkin-Mukhovatoc empirical formulas for plasma densities above a critical density.

  14. Electromagnetic Waves and Bursty Electron Acceleration: Implications from Freja

    NASA Technical Reports Server (NTRS)

    Andersson, Laila; Ivchenko, N.; Wahlund, J.-E.; Clemmons, J.; Gustavsson, B.; Eliasson, L.

    2000-01-01

    Dispersive Alfven wave activity is identified in four dayside auroral oval events measured by the Freja satellite. The events are characterized by ion injection, bursty electron precipitation below about I keV, transverse ion heating and broadband extremely low frequency (ELF) emissions below the lower hybrid cutoff frequency (a few kHz). The broadband emissions are observed to become more electrostatic towards higher frequencies. Large-scale density depletions/cavities, as determined by the Langmuir probe measurements, and strong electrostatic emissions are often observed simultaneously. A correlation study has been carried out between the E- and B-field fluctuations below 64 Hz (the dc instrument's upper threshold) and the characteristics of the precipitating electrons. This study revealed that the energization of electrons is indeed related to the broadband ELF emissions and that the electrostatic component plays a predominant role during very active magnetospheric conditions. Furthermore, the effect of the ELF electromagnetic emissions on the larger scale field-aligned current systems has been investigated, and it is found that such an effect cannot be detected. Instead, the Alfvenic activity creates a local region of field-aligned currents. It is suggested that dispersive Alfven waves set up these local field-aligned current regions and in turn trigger more electrostatic emissions during certain conditions. In these regions ions are transversely heated, and large-scale density depletions/cavities may be created during especially active periods.

  15. Nonlinear Generation of Electromagnetic Waves Through Scattering by Thermal Electrons

    NASA Astrophysics Data System (ADS)

    Tejero, E. M.; Crabtree, C. E.; Blackwell, D. D.; Amatucci, B.; Mithaiwala, M.; Rudakov, L.; Ganguli, G.

    2014-12-01

    Nonlinear interactions involving whistler wave turbulence are important contributors to radiation belt dynamics, including the acceleration and loss of trapped electrons. Given sufficient whistler energy density, nonlinear scattering from thermal electrons can substantially change the wave normal angle, while inducing a small frequency shift [Ganguli et al., 2010]. This nonlinear process is being studied in the NRL Space Physics Simulation Chamber (SPSC) in scaled magnetospheric conditions. The plasma response as a function of transmitted lower hybrid wave amplitude is monitored with magnetic loop antennas. Measurements of the magnetic field vectors for the pump and daughter waves allow for the determination of wave distribution functions, which indicate the power distribution as a function of wave-normal angle and azimuthal angle. The wave distribution functions measured in the experiment demonstrate a dramatic change in propagation direction when the launched wave amplitude exceeds a small threshold (δB / B ~ 4 × 10-7). The experimental results support the theory of electromagnetic whistler wave generation through nonlinear scattering of electrostatic lower hybrid waves by thermal electrons in the Earth's magnetosphere [Crabtree et al, 2012].

  16. Chaotic electron trajectories in an electromagnetic wiggler free-electron laser with ion-channel guiding

    SciTech Connect

    Taghavi, Amin; Esmaeilzadeh, Mahdi; Fallah, Mohammad S.

    2010-09-15

    Chaotic behavior of an electron motion in combined backward propagating electromagnetic wiggler and ion-channel electrostatic fields is studied. The Poincare surface-of-sections are employed to investigate chaotic behavior of electron motion. It is shown that the electron motion can exhibit chaotic behavior when the ion-channel density is low or medium, while for sufficiently high ion-channel density, the electron motion becomes regular (nonchaotic). Also, the chaotic trajectories decrease when the effects of self-fields of electron beam are taken into account and under Budker condition all trajectories become regular. The above result is in contrast with magnetostatic helical wiggler with axial magnetic field in which chaotic motion is produced by self-fields of electron beam. The chaotic and nonchaotic electron trajectories are confirmed by calculating Liapunov exponents.

  17. Chaotic electron trajectories in an electromagnetic wiggler free-electron laser with ion-channel guiding

    NASA Astrophysics Data System (ADS)

    Taghavi, Amin; Esmaeilzadeh, Mahdi; Fallah, Mohammad S.

    2010-09-01

    Chaotic behavior of an electron motion in combined backward propagating electromagnetic wiggler and ion-channel electrostatic fields is studied. The Poincaré surface-of-sections are employed to investigate chaotic behavior of electron motion. It is shown that the electron motion can exhibit chaotic behavior when the ion-channel density is low or medium, while for sufficiently high ion-channel density, the electron motion becomes regular (nonchaotic). Also, the chaotic trajectories decrease when the effects of self-fields of electron beam are taken into account and under Budker condition all trajectories become regular. The above result is in contrast with magnetostatic helical wiggler with axial magnetic field in which chaotic motion is produced by self-fields of electron beam. The chaotic and nonchaotic electron trajectories are confirmed by calculating Liapunov exponents.

  18. Hot electron cooling by acoustic phonons in graphene.

    PubMed

    Betz, A C; Vialla, F; Brunel, D; Voisin, C; Picher, M; Cavanna, A; Madouri, A; Fève, G; Berroir, J-M; Plaçais, B; Pallecchi, E

    2012-08-01

    We have investigated the energy loss of hot electrons in metallic graphene by means of GHz noise thermometry at liquid helium temperature. We observe the electronic temperature T ∝ V at low bias in agreement with the heat diffusion to the leads described by the Wiedemann-Franz law. We report on T ∝ √V behavior at high bias, which corresponds to a T(4) dependence of the cooling power. This is the signature of a 2D acoustic phonon cooling mechanism. From a heat equation analysis of the two regimes we extract accurate values of the electron-acoustic phonon coupling constant Σ in monolayer graphene. Our measurements point to an important effect of lattice disorder in the reduction of Σ, not yet considered by theory. Moreover, our study provides a strong and firm support to the rising field of graphene bolometric detectors. PMID:23006198

  19. 49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation Other Regulations Relating to... characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the functioning...

  20. 49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation Other Regulations Relating to... characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the functioning...

  1. 49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation Other Regulations Relating to... characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the functioning...

  2. 49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation Other Regulations Relating to... characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the functioning...

  3. 49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation Other Regulations Relating to... characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the functioning...

  4. Progress on a cryogenically cooled RF gun polarized electron source

    SciTech Connect

    Fliller, R.P., III; Edwards, H.; /Fermilab

    2006-08-01

    RF guns have proven useful in multiple accelerator applications. An RF gun capable of producing polarized electrons is an attractive electron source for the ILC or an electron-ion collider. Producing such a gun has proven elusive. The NEA GaAs photocathode needed for polarized electron production is damaged by the vacuum environment in an RF gun. Electron and ion back bombardment can also damage the cathode. These problems must be mitigated before producing an RF gun polarized electron source. In this paper we report continuing efforts to improve the vacuum environment in a normal conducting RF gun by cooling it with liquid nitrogen after a high temperature vacuum bake out. We also report on a design of a cathode preparation chamber to produce bulk GaAs photocathodes for testing in such a gun. Future directions are also discussed.

  5. Modulational instabilities of electromagnetic electron cyclotron waves in a dense magnetized plasma

    SciTech Connect

    Rios, L. A.; Shukla, P. K.

    2008-07-15

    Modulational instabilities of electromagnetic electron-cyclotron waves in a dense magnetized plasma are investigated. Dispersion relations for the modulational instabilities are derived and analyzed. The effects of quantum statistical pressure and quantum electron tunneling are discussed.

  6. Two-Phase Cooling Method Using R134a Refrigerant to Cool Power Electronic Devices

    SciTech Connect

    Lowe, Kirk T; Tolbert, Leon M; Ayers, Curtis William; Ozpineci, Burak; Campbell, Jeremy B

    2007-01-01

    This paper presents a two-phase cooling method using R134a refrigerant to dissipate the heat energy (loss) generated by power electronics (PE) such as those associated with rectifiers, converters, and inverters for a specific application in hybrid-electric vehicles (HEVs). The cooling method involves submerging PE devices in an R134a bath, which limits the junction temperature of PE devices while conserving weight and volume of the heat sink without sacrificing equipment reliability. First, experimental tests that included an extended soak for more than 300 days were performed on a submerged IGBT and gate-controller card to study dielectric characteristics, deterioration effects, and heat flux capability of R134a. Results from these tests illustrate that R134a has high dielectric characteristics, no deterioration on electrical components, and a heat flux of 114 W/cm 2 for the experimental configuration. Second, experimental tests that included simultaneous operation with a mock automotive air-conditioner (A/C) system were performed on the same IGBT and gate controller card. Data extrapolation from these tests determined that a typical automotive A/C system has more than sufficient cooling capacity to cool a typical 30 kW traction inverter. Last, a discussion and simulation of active cooling of the IGBT junction layer with R134a refrigerant is given. This technique will drastically increase the forward current ratings and reliability of the PE device

  7. Part II/Addendum Electron Beam Cooling between EBIS LINAC and Booster; Is Single Pass Cooling Possible?

    SciTech Connect

    Hershcovitch,A.

    2008-07-01

    Due to some miscommunication, incomplete data was erroneously used in examining electron beam cooling for reducing momentum of gold ions exiting the EBIS LINAC before injection into the booster. Corrected calculations still indicate that single pass cooling is, in principle, feasible; momentum spread can be reduced by an order of magnitude in about one meter. Preliminary results suggest that this cooling deserves further consideration.

  8. HADRON ACCELERATORS: Commissioning of electron cooling in CSRm

    NASA Astrophysics Data System (ADS)

    Yang, Xiao-Dong; Li, Jie; Mao, Li-Jun; Li, Guo-Hong; Zhan, Wen-Long; Xia, Jia-Wen; Zhao, Hong-Wei; Xiao, Guo-Qing; Yuan, You-Jin; Song, Ming-Tao; Liu, Yong; Yang, Jian-Cheng; Gao, Da-Qing; Zhou, Zhong-Zu; He, Yuan; Zhang, Wei; Zhang, Jian-Hua; Mao, Rui-Shi; Zhao, Tie-Cheng; Parkhomchuk, Vasily

    2009-06-01

    A new generation electron cooler has started operation in the heavy ion synchrotron CSRm which is used to increase the intensity of heavy ions. Transverse cooling of the ion beam after horizontal multi-turn injection allows beam accumulation at the injection energy. After optimization of the accumulation process an intensity increase in a synchrotron pulse by more than one order of magnitude has been achieved. In given accumulation time interval of 10 seconds, 108 particles have been accumulated and accelerated to the final energy. The momentum spread after accumulation and acceleration in the 10-4 range has been demonstrated in six species of ion beams. Primary measurements of accumulation process varying with electron energy, electron beam current, electron beam profile, expansion factor and injection interval have been performed. The lifetimes of ion beams in the presence of electron beams were roughly measured with the help of DCCT signal.

  9. Dynamics of R.F. Captured Electron Cooled Proton Beams

    SciTech Connect

    Kells, W.; Mills, F.;

    1983-01-01

    In the course of electron cooling experiments at the Electron Cooling Ring (ECR) at Fermilab, several peculiar features of the longitudinal phase space of cold protons (200 MeV) captured in R.F. buckets were observed. Here we present the experimental facts, present a simple theory, and summarize computer simulation results which support the theory and facts. The experimental apparatus and measurement techniques have been described elsewhere. R.F. bunching was achieved with a single PPA, loaded cavity gap driven at harmonic number 6({approx} 7.56 MHz) of the revolution frequency. R.F. voltage could be developed across this gap sufficient to entirely capture even the uncooled circulating proton beam ({delta}p/p FWHM = 0.17%).

  10. Feasibility of Electron Cooling for Low-Energy RHIC Operation

    SciTech Connect

    Fedotov,A.; Ben-Zvi, I.; Chang, X.; Kayran, D.; Litvinenko, V.; Pozdeyev, E.; Satogata, T.

    2008-04-01

    A concrete interest in running RHIC at low energies in a range of 2.5-25 GeV/nucleon total energy of a single beam has recently emerged. Providing collisions in this energy range, which in the RHIC case is termed 'low-energy' operation, will help to answer one of the key questions in the field of QCD about existence and location of a critical point on the QCD phase diagram. However, luminosity projections are relatively low for the lowest energy points of interest. Luminosity improvement can be provided with electron cooling applied directly in RHIC at low energies. This report summarizes the expected luminosity improvement with electron cooling, possible technical approaches and various limitations.

  11. Properties of electrons scattered by a strong plane electromagnetic wave with a linear polarization: Semiclassical treatment

    NASA Astrophysics Data System (ADS)

    Bogdanov, O. V.; Kazinski, P. O.

    2015-02-01

    The problem of scattering of ultrarelativistic electrons by a strong plane electromagnetic wave of a low (optical) frequency and linear polarization is solved in the semiclassical approximation, when the electron wave packet size is much smaller than the wavelength of electromagnetic wave. The exit momenta of ultrarelativistic electrons scattered are found using the exact solutions to the equations of motion with radiation reaction included (the Landau-Lifshitz equation). It is found that the momentum components of electrons traversed the electromagnetic wave depend weakly on the initial values of momenta. These electrons are mostly scattered at small angles to the propagation direction of the electromagnetic wave. The maximum Lorentz factor of electrons crossed the electromagnetic wave is proportional to the work done by the electromagnetic field and is independent of the initial momentum. The momentum component parallel to the electric field vector of the electromagnetic wave is determined solely by the laser beam diameter measured in the units of the classical electron radius. As for the reflected electrons, they for the most part lose the energy, but remain relativistic. A reflection law that relates the incident and reflection angles and is independent of any parameters is found.

  12. Analysis and simulation for laser-Compton cooling of electron beams

    SciTech Connect

    Ohgaki, T.

    1999-10-01

    The method of the Laser-Compton cooling of the electron beams is studied. Using a Monte Carlo code, we have evaluated the effects of the Laser-electron interaction for cooling. The optics with and without chromatic correction for cooling are examined. Problems of the optics for cooling are discussed.

  13. Program Package of Photoinduced Electron Dynamics: GCEED (Grid-based Coupled Electron and Electromagnetic field Dynamics)

    NASA Astrophysics Data System (ADS)

    Noda, Masashi; Ishimura, Kazuya; Nobusada, Katsuyuki

    We have developed a massively parallel program package of photoinduced electron dynamics simulations, GCEED (Grid-based Coupled Electron and Electromagnetic field Dynamics), which is based on time-dependent density functional theory calculations in real-time and real-space. The performance of the Taylor expansion for the time-propagation is verified in terms of the computational cost and accuracy by varying the order of the expansion and the time step width. It is found that the fourth order expansion gives the best performance and the maximum time step widths at each order are the same regardless of the element and the system size.

  14. Weak and electromagnetic mechanisms of neutrino-pair photoproduction in a strongly magnetized electron gas

    SciTech Connect

    Borisov, A. V.; Kerimov, B. K.; Sizin, P. E.

    2012-11-15

    Expressions for the power of neutrino radiation from a degenerate electron gas in a strong magnetic field are derived for the case of neutrino-pair photoproduction via the weak and electromagnetic interaction mechanisms (it is assumed that the neutrino possesses electromagnetic form factors). It is shown that the neutrino luminosity of a medium in the electromagnetic reaction channel may exceed substantially the luminosity in the weak channel. Relative upper bounds on the effective neutrino magnetic moment are obtained.

  15. Detecting and locating electronic devices using their unintended electromagnetic emissions

    NASA Astrophysics Data System (ADS)

    Stagner, Colin Blake

    Electronically-initiated explosives can have unintended electromagnetic emissions which propagate through walls and sealed containers. These emissions, if properly characterized, enable the prompt and accurate detection of explosive threats. The following dissertation develops and evaluates techniques for detecting and locating common electronic initiators. The unintended emissions of radio receivers and microcontrollers are analyzed. These emissions are low-power radio signals that result from the device's normal operation. In the first section, it is demonstrated that arbitrary signals can be injected into a radio receiver's unintended emissions using a relatively weak stimulation signal. This effect is called stimulated emissions. The performance of stimulated emissions is compared to passive detection techniques. The novel technique offers a 5 to 10 dB sensitivity improvement over passive methods for detecting radio receivers. The second section develops a radar-like technique for accurately locating radio receivers. The radar utilizes the stimulated emissions technique with wideband signals. A radar-like system is designed and implemented in hardware. Its accuracy tested in a noisy, multipath-rich, indoor environment. The proposed radar can locate superheterodyne radio receivers with a root mean square position error less than 5 meters when the SNR is 15 dB or above. In the third section, an analytic model is developed for the unintended emissions of microcontrollers. It is demonstrated that these emissions consist of a periodic train of impulses. Measurements of an 8051 microcontroller validate this model. The model is used to evaluate the noise performance of several existing algorithms. Results indicate that the pitch estimation techniques have a 4 dB sensitivity improvement over epoch folding algorithms.

  16. The noise-cooling tradeoff in electronic equipment

    NASA Astrophysics Data System (ADS)

    Lyon, Richard H.

    2001-05-01

    The noise produced by cooling air passing through electronics packages arises from two sources. One source is the noise of the air-moving fan of either an axial or centrifugal type. This noise may have tonal components and both those components and the broad band noise are dependent on the way that the fan is placed in the unit and on how close the operation is to the design operating point. Often, this can be the dominant noise source. The other source produces random noise due to the turbulent flow of air through the unit. Because the turbulent airflow is also responsible for heat transfer between the components and the air stream, we can regard this part of the noise as the irreducible noise due to cooling. If fan noise were eliminated, this part of the noise must remain. There is a relation therefore between the irreducible noise and the cooling of the unit. But the fan noise must also be considered. The relation between total airflow related noise and cooling requirements is developed in this paper.

  17. Stimulated Raman up-conversion of electromagnetic waves by a gyrating electron beam

    NASA Technical Reports Server (NTRS)

    Sharma, O. P.; Patel, V. L.

    1983-01-01

    A gyrating electron beam supports negative energy modes near the harmonics of electron-cyclotron frequency. An electromagnetic wave passing through such a beam parametrically up-converts into high-frequency electromagnetic modes separated from the pump frequency by the electron-cyclotron harmonics. The growth rate for this process varies directly as the oscillatory velocity of beam electrons caused by the pump and as square root of the beam density. It has a maximum at values of scattering angle close to 180 deg and is also implicitly dependent on the beam veocity and the cyclotron frequency of electrons. The effect of a cold electron component is to reduce the growth rate.

  18. Cooled electronic system with thermal spreaders coupling electronics cards to cold rails

    DOEpatents

    Chainer, Timothy J; Gaynes, Michael A; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Schultz, Mark D; Simco, Daniel P; Steinke, Mark E

    2013-07-23

    Liquid-cooled electronic systems are provided which include an electronic assembly having an electronics card and a socket with a latch at one end. The latch facilitates securing of the card within the socket or removal of the card from the socket. A liquid-cooled cold rail is disposed at the one end of the socket, and a thermal spreader couples the electronics card to the cold rail. The thermal spreader includes first and second thermal transfer plates coupled to first and second surfaces on opposite sides of the card, and thermally conductive extensions extending from end edges of the plates, which couple the respective transfer plates to the liquid-cooled cold rail. The thermally conductive extensions are disposed to the sides of the latch, and the card is securable within or removable from the socket using the latch without removing the cold rail or the thermal spreader.

  19. Influence of electron evaporative cooling on ultracold plasma expansion

    SciTech Connect

    Wilson, Truman; Chen, Wei-Ting; Roberts, Jacob

    2013-07-15

    The expansion of ultracold neutral plasmas (UCP) is driven primarily by the thermal pressure of the electron component and is therefore sensitive to the electron temperature. For typical UCP spatial extents, evaporative cooling has a significant influence on the UCP expansion rate at lower densities (less than 10{sup 8}/cm{sup 3}). We studied the effect of electron evaporation in this density range. Owing to the low density, the effects of three-body recombination were negligible. We modeled the expansion by taking into account the change in electron temperature owing to evaporation as well as adiabatic expansion and found good agreement with our data. We also developed a simple model for initial evaporation over a range of ultracold plasma densities, sizes, and electron temperatures to determine over what parameter range electron evaporation is expected to have a significant effect. We also report on a signal calibration technique, which relates the signal at our detector to the total number of ions and electrons in the ultracold plasma.

  20. An electromagnetic energy harvester for powering consumer electronics

    NASA Astrophysics Data System (ADS)

    Liu, Xiyuan

    This thesis introduces an electromagnetic vibratory energy harvester to power consumer electronics by generating electricity from the strides taken during walking or jogging. The harvester consists of a magnetic pendulum oscillating between two fixed magnets. The pendulum behaves similar to a rotor in a DC generator, while the fixed magnets, which are poled opposite to the pendulum, provide magnetic restoring forces similar to mechanical springs. When attached to a person's arm, the swinging motion subjects the magnetic pendulum to base excitations. Consequently, the pendulum oscillates near a stator which has three poles of wound copper coils. The motion of the pendulum induces a time-varying magnetic field in the flux path which generates electricity in the coils as per Faraday's law. To better understand the response behavior of the device, the thesis presents a nonlinear electromechanical model that describes the interaction between the mechanical and electrical subsystems. Experimental system identification is then implemented to characterize several unknown design parameters, including the nonlinear magnetic restoring torque, the mechanical damping coefficient, and the electromechanical coupling. The derived nonlinear mathematical model, which mimics the behavior of a damped Duffing oscillator, is then solved analytically using the method of multiple scales and the results are compared to experimental data showing good agreement for the design parameters considered. The performance of the device in charging a small battery while jogging is investigated. The motion of a typical swinging arm in terms of frequency and acceleration is reproduced on an electrodynamic shaker and used to charge a 100 μAh battery yielding an estimated charging time of 12 minutes.

  1. Hot electron cooling in graphite: Supercollision versus hot phonon decay

    NASA Astrophysics Data System (ADS)

    Stange, A.; Sohrt, C.; Yang, L. X.; Rohde, G.; Janssen, K.; Hein, P.; Oloff, L.-P.; Hanff, K.; Rossnagel, K.; Bauer, M.

    2015-11-01

    Disorder-assisted electron-phonon scattering processes (supercollision processes) have been reported to dominate the cooling of hot carriers in graphene. Here, we determine to what extent this type of relaxation mechanism governs the hot carrier dynamics in the parent compound graphite. Electron temperature transients derived from time- and angle-resolved extreme ultraviolet photoemission spectra are analyzed based on a three-temperature model which considers electron gas, optical phonons, and acoustic phonons as coupled subsystems. In the probed fluence regime of 0.035 -1.4 mJ /cm2 , we find no indications for supercollision processes being involved in the cooling of the hot carriers. The data are, by contrast, compatible with a hot phonon assisted mechanism involving anharmonic coupling between optical phonons and acoustic phonons, a process which has previously been suggested for graphite. We attribute the striking difference to the reported findings for (substrate-supported) graphene to the low defect density of highly ordered pyrolitic graphite.

  2. Theory of atoms in strong, pulsed electromagnetic fields: 2, A free electron and a harmonically bound electron

    SciTech Connect

    Szoeke, A.; Garrison, J.

    1987-07-01

    Multiple scale methods are used to treat several ingredients of the theory of atoms in strong electromagnetic fields. First, a focused electromagnetic field is expanded. Second, a classical electron is described giving the ponderomotive potential. Third, the quantum electron is treated in the WKB approximation. Fourth, the one dimensional quantum harmonic oscillator is solved; and last the one dimensional square well, showing the low intensity limit of the theory.

  3. Heating of the lower ionosphere electrons by electromagnetic radiation of lightning discharges

    SciTech Connect

    Nickolaenko, A.P.; Hayakawa, M.

    1995-11-15

    This report investigates the heating effects on electrons that occur at the lower edge of the ionosphere due to the incidence of electromagnetic pulses radiated from discharges of lightning. Two tradiational models of the median return stroke is also considered.

  4. Electronic spectroscopy of jet-cooled vinyl radical

    NASA Astrophysics Data System (ADS)

    Pushkarsky, Michael B.; Mann, Aaron M.; Yeston, Jake S.; Moore, C. Bradley

    2001-12-01

    The spectra of the X˜2A'-Ã2A″ electronic transition of jet-cooled vinyl radical, C2H3, and its partially deuterated isotopomer, CD2CH, have been obtained via action spectroscopy. The appearance of the H or D fragment was monitored via 1+1' resonance enhanced multiphoton ionization through the Lyman-α transition. The vibrational structure of the Ã2A″ state was fully resolved and analyzed. The experimental vibrational frequencies agree well with ab initio calculations. The simulation of the rotational structure of several bands reinforces vibrational assignments.

  5. Diffusion-Cooled Tantalum Hot-Electron Bolometer Mixers

    NASA Technical Reports Server (NTRS)

    Skalare, Anders; McGrath, William; Bumble, Bruce; LeDuc, Henry

    2004-01-01

    A batch of experimental diffusion-cooled hot-electron bolometers (HEBs), suitable for use as mixers having input frequencies in the terahertz range and output frequencies up to about a gigahertz, exploit the superconducting/normal-conducting transition in a thin strip of tantalum. The design and operation of these HEB mixers are based on mostly the same principles as those of a prior HEB mixer that exploited the superconducting/normal- conducting transition in a thin strip of niobium and that was described elsewhere.

  6. Air Cooling for High Temperature Power Electronics (Presentation)

    SciTech Connect

    Waye, S.; Musselman, M.; King, C.

    2014-09-01

    Current emphasis on developing high-temperature power electronics, including wide-bandgap materials such as silicon carbide and gallium nitride, increases the opportunity for a completely air-cooled inverter at higher powers. This removes the liquid cooling system for the inverter, saving weight and volume on the liquid-to-air heat exchanger, coolant lines, pumps, and coolant, replacing them with just a fan and air supply ducting. We investigate the potential for an air-cooled heat exchanger from a component and systems-level approach to meet specific power and power density targets. A proposed baseline air-cooled heat exchanger design that does not meet those targets was optimized using a parametric computational fluid dynamics analysis, examining the effects of heat exchanger geometry and device location, fixing the device heat dissipation and maximum junction temperature. The CFD results were extrapolated to a full inverter, including casing, capacitor, bus bar, gate driver, and control board component weights and volumes. Surrogate ducting was tested to understand the pressure drop and subsequent system parasitic load. Geometries that met targets with acceptable loads on the system were down-selected for experimentation. Nine baseline configuration modules dissipated the target heat dissipation, but fell below specific power and power density targets. Six optimized configuration modules dissipated the target heat load, exceeding the specific power and power density targets. By maintaining the same 175 degrees C maximum junction temperature, an optimized heat exchanger design and higher device heat fluxes allowed a reduction in the number of modules required, increasing specific power and power density while still maintaining the inverter power.

  7. SIMULATIONS OF RHIC COHERENT STABILITIES DUE TO WAKEFIELD AND ELECTRON COOLING

    SciTech Connect

    WANG,G.; BLASKIEWICZ, M.

    2007-06-25

    The Electron cooling beam has both coherent and incoherent effects to the circulating ion beam. The incoherent longitudinal cooling could reduce the ion beam energy spread and hence cause 'over-cooling' of the ion beam. Depending on the beam densities and cooling length, the coherent interaction between the ion and electron beam could either damp or anti-damp the ion coherent motions. Using the tracking codes, TRANFT, the threshold for 'over-cooling' has been found and compared with theoretical estimation. The transverse coherent effect of electron cooling has been implemented into the codes and its effect for the bunched ion beam is shown.

  8. Beam-Based Alignment of Magnetic Field in the Fermilab Electron Cooler Cooling Section

    SciTech Connect

    Seletskiy, S. M.; Tupikov, V.

    2006-03-20

    The Fermilab Electron Cooling Project requires low effective anglular spread of electrons in the cooling section. One of the main components of the effective electron angles is an angle of electron beam centroid with respect to antiproton beam. This angle is caused by the poor quality of magnetic field in the 20 m long cooling section solenoid and by the mismatch of the beam centroid to the entrance of the cooling section. This paper focuses on the beam-based procedure of the alignment of the cooling section field and beam centroid matching. The discussed procedure allows to suppress the beam centroid angles below the critical value of 0.1 mrad.

  9. Thermoelectric-enhanced, liquid-based cooling of a multi-component electronic system

    SciTech Connect

    Chainer, Timothy J; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Steinke, Mark E

    2015-05-12

    Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled structure, a thermal conduction path coupling the electronic component and the liquid-cooled structure, a coolant loop in fluid communication with a coolant-carrying channel of the liquid-cooled structure, and an outdoor-air-cooled heat exchange unit coupled to facilitate heat transfer from the liquid-cooled structure via, at least in part, the coolant loop. The thermoelectric array facilitates transfer of heat from the electronic component to the liquid-cooled structure, and the heat exchange unit cools coolant passing through the coolant loop by dissipating heat from the coolant to outdoor ambient air. In one implementation, temperature of coolant entering the liquid-cooled structure is greater than temperature of the outdoor ambient air to which heat is dissipated.

  10. Thermoelectric-enhanced, liquid-based cooling of a multi-component electronic system

    SciTech Connect

    Chainer, Timothy J; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Steinke, Mark E

    2015-11-10

    Methods are provided for facilitating cooling of an electronic component. The methods include providing: a liquid-cooled structure, a thermal conduction path coupling the electronic component and the liquid-cooled structure, a coolant loop in fluid communication with a coolant-carrying channel of the liquid-cooled structure, and an outdoor-air-cooled heat exchange unit coupled to facilitate heat transfer from the liquid-cooled structure via, at least in part, the coolant loop. The thermoelectric array facilitates transfer of heat from the electronic component to the liquid-cooled structure, and the heat exchange unit cools coolant passing through the coolant loop by dissipating heat from the coolant to outdoor ambient air. In one implementation, temperature of coolant entering the liquid-cooled structure is greater than temperature of the outdoor ambient air to which heat is dissipated.

  11. Vibrational and rotational cooling of electrons by molecular hydrogen. [in Jupiter and Saturn thermosphere

    NASA Technical Reports Server (NTRS)

    Waite, J. H., Jr.; Cravens, T. E.

    1981-01-01

    It is noted that the cooling of electrons by vibrational and rotational excitation of molecular hydrogen plays an important role in the thermal balance of electrons in atmospheres containing significant amounts of H2. Calculations are described of vibrational and rotational cooling rates of electrons by H2. Results for a wide range of electron and neutral temperatures are presented, and analytical formulas for some to the cooling rates are given.

  12. Electromagnetic radiation and nonlinear energy flow in an electron beam-plasma system

    NASA Technical Reports Server (NTRS)

    Whelan, D. A.; Stenzel, R. L.

    1985-01-01

    It is shown that the unstable electron-plasma waves of a beam-plasma system can generate electromagnetic radiation in a uniform plasma. The generation mechanism is a scattering of the unstable electron plasma waves off ion-acoustic waves, producing electromagnetic waves whose frequency is near the local plasma frequency. The wave vector and frequency matching conditions of the three-wave mode coupling are experimentally verified. The electromagnetic radiation is observed to be polarized with the electric field parallel to the beam direction, and its source region is shown to be localized to the unstable plasma wave region. The frequency spectrum shows negligible intensity near the second harmonic of the plasma frequency. These results suggest that the observed electromagnetic radiation of type III solar bursts may be generated near the local plasma frequency and observed downstream where the wave frequency is near the harmonic of the plasma frequency.

  13. Efficient regime of electromagnetic emission in a plasma with counterstreaming electron beams

    SciTech Connect

    Timofeev, I. V.; Annenkov, V. V.

    2014-08-15

    Efficiency of electromagnetic emission produced in a magnetized plasma with counterstreaming electron beams was investigated using both the linear kinetic theory and particle-in-cell simulations. We calculated the growth rate of the beam-plasma instability taking into account both kinetic and relativistic effects and showed that there exists a regime in which transversely propagating electromagnetic waves can be generated by the coupling of the most unstable oblique beam-driven modes. It was confirmed by numerical simulations that such a tune-up of system parameters for a specific nonlinear process can lead to a substantial increase in electromagnetic emission efficiency. It was found that electromagnetic radiation emerging from the plasma in such a regime is generated near the harmonics of the pump frequency that is determined by the typical eigenfrequency of the beam-driven modes. It was also shown that the peak emission power can reach 5% of the maximal power lost by beam electrons.

  14. Electron Cooling for Cold Beam Synchrotron for Cancer Therapy

    SciTech Connect

    Grishanov, B.; Parkhomchuk, V.; Rastigeev, S.; Reva, V.; Vostrikov, V.; Kumada, M.

    2006-03-20

    A wide usage of carbon ions for cancer therapy is limited mostly due to technical difficulties, resulting in higher cost. This cost problem can be solved by our CBS (Cold Beam Synchrotron) proposal. In this paper a conceptual design of the facility for the carbon beam cancer therapy using a high precise active beam scanning system of synchronizing with respiration. The main feature of the CBS facility is an application of electron cooling device. The use of cold ion beam allows to decrease the aperture of synchrotron and components of high energy beam transport lines, significantly. The precise ion beam energy variation and two unique schemes of beam extraction ('pellet' extraction and extraction on recombination) enclose the list of possibilities appearing with EC applying.

  15. Smart interactive electronic system for monitoring the electromagnetic activities of biological systems

    NASA Astrophysics Data System (ADS)

    Popa, Sorin G.; Shahinpoor, Mohsen

    2001-08-01

    A novel electronic device capable of sensing and monitoring the myoelectric, polarization wave and electromagnetic activities of the biological systems and in particular the human body is presented. It is known that all the physical and chemical processes within biological systems are associated with polarization, depolarization waves from the brain, neural signals and myoelectric processes that manifest themselves in ionic and dipole motion. The technology developed in our laboratory is based on certain charge motion sensitive electronics. The electronic system developed is capable of sensing the electromagnetic activities of biological systems. The information obtained is then processed by specialized software in order to interpret it from physical and chemical point of view.

  16. The Screening Effect in Electromagnetic Production of Electron Positron Pairs in Relativistic Nucleus-Atom Collisions

    NASA Technical Reports Server (NTRS)

    Wu, Jianshi; Derrickson, J. H.; Parnell, T. A.; Strayer, M. R.

    1999-01-01

    We study the screening effects of the atomic electrons in the electromagnetic production of electron-positron pairs in relativistic nucleus-atom collisions for fixed target experiments. Our results are contrasted with those obtained in bare collisions, with particular attention given to its dependence on the beam energy and the target atom.

  17. Thermal transfer structures coupling electronics card(s) to coolant-cooled structure(s)

    DOEpatents

    David, Milnes P; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Parida, Pritish R; Schmidt, Roger R

    2014-12-16

    Cooling apparatuses and coolant-cooled electronic systems are provided which include thermal transfer structures configured to engage with a spring force one or more electronics cards with docking of the electronics card(s) within a respective socket(s) of the electronic system. A thermal transfer structure of the cooling apparatus includes a thermal spreader having a first thermal conduction surface, and a thermally conductive spring assembly coupled to the conduction surface of the thermal spreader and positioned and configured to reside between and physically couple a first surface of an electronics card to the first surface of the thermal spreader with docking of the electronics card within a socket of the electronic system. The thermal transfer structure is, in one embodiment, metallurgically bonded to a coolant-cooled structure and facilitates transfer of heat from the electronics card to coolant flowing through the coolant-cooled structure.

  18. Trapping of electrons in troughs of self generated electromagnetic standing waves in a bounded plasma column

    SciTech Connect

    Bhattacharjee, Sudeep; Sahu, Debaprasad; Pandey, Shail; Chatterjee, Sanghomitro; Dey, Indranuj; Roy Chowdhury, Krishanu

    2014-01-15

    Observations and measurements are reported on electron trapping in troughs of self-generated electromagnetic standing waves in a bounded plasma column confined in a minimum-B field. The boundaries are smaller than the free space wavelength of the waves. Earlier work of researchers primarily focused upon electron localization effects induced by purely electrostatic perturbation. We demonstrate the possibility in the presence of electromagnetic standing waves generated in the bounded plasma column. The electron trapping is verified with electrostatic measurements of the plasma floating potential, electromagnetic measurements of the wave field profile, and optical intensity measurements of Argon ionic line at 488 nm. The experimental results show a reasonably good agreement with predictions of a Monte Carlo simulation code that takes into account all kinematical and dynamical effects in the plasma in the presence of bounded waves and external fields.

  19. A FIRST LOOK AT BEAM DIAGNOSTICS FOR THE RHIC ELECTRON COOLING PROJECT.

    SciTech Connect

    CAMERON, P.; BEN-ZVI, I.; KEWISCH, J.; LITVINENKO, V.

    2005-06-06

    High energy electron cooling [1] is essential to meet the luminosity specification for RHIC II [2]. In preparation for electron cooling, an Energy Recovery Linac (ERL) test facility [3] is under construction at BNL. A preliminary description of Diagnostics for the ERL was presented at an earlier workshop [4]. A significant portion of the eCooling Diagnostics will be a simple extension of those developed for the ERL test facility. In this paper we present a preliminary report on eCooling Diagnostics. We summarize the planned conventional Diagnostics, and follow with more detailed descriptions of Diagnostics specialized to the requirements of high-energy magnetized cooling.

  20. Modeling Single-Phase and Boiling Liquid Jet Impingement Cooling in Power Electronics

    SciTech Connect

    Narumanchi, S. V. J.; Hassani, V.; Bharathan, D.

    2005-12-01

    Jet impingement has been an attractive cooling option in a number of industries over the past few decades. Over the past 15 years, jet impingement has been explored as a cooling option in microelectronics. Recently, interest has been expressed by the automotive industry in exploring jet impingement for cooling power electronics components. This technical report explores, from a modeling perspective, both single-phase and boiling jet impingement cooling in power electronics, primarily from a heat transfer viewpoint. The discussion is from the viewpoint of the cooling of IGBTs (insulated-gate bipolar transistors), which are found in hybrid automobile inverters.

  1. Kinetic theory of the electron bounce instability in two dimensional current sheets-Full electromagnetic treatment

    NASA Astrophysics Data System (ADS)

    Tur, A.; Fruit, G.; Louarn, P.; Yanovsky, V.

    2014-03-01

    In the general context of understanding the possible destabilization of a current sheet with applications to magnetospheric substorms or solar flares, a kinetic model is proposed for studying the resonant interaction between electromagnetic fluctuations and trapped bouncing electrons in a 2D current sheet. Tur et al. [A. Tur et al., Phys. Plasmas 17, 102905 (2010)] and Fruit et al. [G. Fruit et al., Phys. Plasmas 20, 022113 (2013)] already used this model to investigate the possibilities of electrostatic instabilities. Here, the model is completed for full electromagnetic perturbations. Starting with a modified Harris sheet as equilibrium state, the linearized gyrokinetic Vlasov equation is solved for electromagnetic fluctuations with period of the order of the electron bounce period. The particle motion is restricted to its first Fourier component along the magnetic field and this allows the complete time integration of the non local perturbed distribution functions. The dispersion relation for electromagnetic modes is finally obtained through the quasineutrality condition and the Ampere's law for the current density. It is found that for mildly strechted current, undamped modes oscillate at typical electron bounce frequency with wavelength of the order of the plasma sheet half thickness. As the stretching of the plasma sheet becomes more intense, the frequency of these normal modes decreases and beyond a certain threshold in ? = Bz/Blobes, the mode becomes explosive with typical growth rate of a few tens of seconds. The free energy contained in the bouncing motion of the electrons may trigger an electromagnetic instability able to disrupt the cross-tail current in a few seconds. This new instability-electromagnetic electron-bounce instability-may explain fast and global scale destabilization of current sheets as required to describe substorm phenomena.

  2. Kinetic theory of the electron bounce instability in two dimensional current sheets—Full electromagnetic treatment

    SciTech Connect

    Tur, A.; Fruit, G.; Louarn, P.

    2014-03-15

    In the general context of understanding the possible destabilization of a current sheet with applications to magnetospheric substorms or solar flares, a kinetic model is proposed for studying the resonant interaction between electromagnetic fluctuations and trapped bouncing electrons in a 2D current sheet. Tur et al. [A. Tur et al., Phys. Plasmas 17, 102905 (2010)] and Fruit et al. [G. Fruit et al., Phys. Plasmas 20, 022113 (2013)] already used this model to investigate the possibilities of electrostatic instabilities. Here, the model is completed for full electromagnetic perturbations. Starting with a modified Harris sheet as equilibrium state, the linearized gyrokinetic Vlasov equation is solved for electromagnetic fluctuations with period of the order of the electron bounce period. The particle motion is restricted to its first Fourier component along the magnetic field and this allows the complete time integration of the non local perturbed distribution functions. The dispersion relation for electromagnetic modes is finally obtained through the quasineutrality condition and the Ampere's law for the current density. It is found that for mildly strechted current, undamped modes oscillate at typical electron bounce frequency with wavelength of the order of the plasma sheet half thickness. As the stretching of the plasma sheet becomes more intense, the frequency of these normal modes decreases and beyond a certain threshold in ε = B{sub z}/B{sub lobes}, the mode becomes explosive with typical growth rate of a few tens of seconds. The free energy contained in the bouncing motion of the electrons may trigger an electromagnetic instability able to disrupt the cross-tail current in a few seconds. This new instability–electromagnetic electron-bounce instability–may explain fast and global scale destabilization of current sheets as required to describe substorm phenomena.

  3. Electrons in a relativistic-intensity laser field: generation of zeptosecond electromagnetic pulses and energy spectrum of the accelerated electrons

    SciTech Connect

    Andreev, A A; Galkin, A L; Kalashnikov, M P; Korobkin, V V; Romanovsky, Mikhail Yu; Shiryaev, O B

    2011-08-31

    We study the motion of an electron and emission of electromagnetic waves by an electron in the field of a relativistically intense laser pulse. The dynamics of the electron is described by the Newton equation with the Lorentz force in the right-hand side. It is shown that the electrons may be ejected from the interaction region with high energy. The energy spectrum of these electrons and the technique of using the spectrum to assess the maximal intensity in the focus are analysed. It is found that electromagnetic radiation of an electron moving in an intense laser field occurs within a small angle around the direction of the electron trajectory tangent. The tangent quickly changes its direction in space; therefore, electromagnetic radiation of the electron in the far-field zone in a certain direction in the vicinity of the tangent is a short pulse with a duration as short as zeptoseconds. The calculation of the temporary and spectral distribution of the radiation field is carried out. (superintense laser fields)

  4. Nano-PCMs for passive electronic cooling applications

    NASA Astrophysics Data System (ADS)

    Colla, L.; Fedele, L.; Mancin, S.; Buonomo, B.; Ercole, D.; Manca, O.

    2015-11-01

    The present work aims at investigating a new challenging use of oxide (TiO2, Al2O3, etc.) nanoparticles to enhance the thermal properties: thermal conductivity, specific heat, and latent heat of pure paraffin waxes to obtain a new class of Phase Change Materials (PCMs), the so-called nano-PCMs. The nano-PCMs were obtained by seeding different amounts of oxide nanoparticles in a paraffin wax having a melting temperature of 45°C. The thermophysical properties such as latent heat and thermal conductivity were then measured to understand the effects of the nanoparticles on the thermal properties of both the solid and liquid PCM. Finally, a numerical comparison between the use of the pure paraffin wax and the nano-PCM in a typical electronics passive cooling device was implemented. Numerical simulations were carried out using the Ansys-Fluent 15.0 code. Results in terms of solid and liquid phase temperatures, melting time and junction temperature were reported. Moreover, a comparison with experimental results was also performed.

  5. Spray cooling characteristics of nanofluids for electronic power devices

    NASA Astrophysics Data System (ADS)

    Hsieh, Shou-Shing; Leu, Hsin-Yuan; Liu, Hao-Hsiang

    2015-03-01

    The performance of a single spray for electronic power devices using deionized (DI) water and pure silver (Ag) particles as well as multi-walled carbon nanotube (MCNT) particles, respectively, is studied herein. The tests are performed with a flat horizontal heated surface using a nozzle diameter of 0.5 mm with a definite nozzle-to-target surface distance of 25 mm. The effects of nanoparticle volume fraction and mass flow rate of the liquid on the surface heat flux, including critical heat flux (CHF), are explored. Both steady state and transient data are collected for the two-phase heat transfer coefficient, boiling curve/ cooling history, and the corresponding CHF. The heat transfer removal rate can reach up to 274 W/cm2 with the corresponding CHF enhancement ratio of 2.4 for the Ag/water nanofluids present at a volume fraction of 0.0075% with a low mass flux of 11.9 × 10-4 kg/cm2s.

  6. Commissioning of Fermilab's electron cooling system for 8-GeV antiprotons

    SciTech Connect

    Nagaitsev, S.; Broemmelsiek, D.; Burov, A.; Carlson, K.; Gattuso, C.; Hu, M.; Kramper, B.; Kroc, T.; Leibfritz, J.; Prost, L.; Pruss, S.; Saewert, G.; Schmidt, C.W.; Shemyakin, A.; Sutherland, M.; Tupikov, V.; Warner, A.; Seletsky, S.; Gai, W.; Kazakevich, Grigory M.; /Novosibirsk, IYF

    2005-05-01

    A 4.3-MeV electron cooling system [1] has been installed at Fermilab in the Recycler antiproton storage ring and is currently being commissioned. The cooling system is designed to assist accumulation of 8.9-GeV/c antiprotons for the Tevatron collider operations. This paper reports on the progress of the electron beam commissioning effort as well as on detailed plans of demonstrating the cooling of antiprotons.

  7. Electron cooling of 8-GeV antiprotons at Fermilab's Recycler: Results and operational implications

    SciTech Connect

    Prost, L.R.; Broemmelsiek, D.; Burov, Alexey V.; Carlson, K.; Gattuso, C.; Hu, M.; Kroc, T.; Leibfritz, J.; Nagaitsev, S.; Pruss, S.; Saewert, G.; Schmidt, C.W.; Shemyakin, A.; Sutherland, M.; Tupikov, V.; Warner, A.; /Fermilab

    2006-05-01

    Electron cooling of 8 GeV antiprotons at Fermilab's Recycler storage ring is now routinely used in the collider operation. It requires a 0.1-0.5 A, 4.3 MeV dc electron beam and is designed to increase the longitudinal phase-space density of the circulating antiproton beam. This paper briefly describes the characteristics of the electron beam that were achieved to successfully cool antiprotons. Then, results from various cooling force measurements along with comparison to a nonmagnetized model are presented. Finally, operational aspects of the implementation of electron cooling at the Recycler are discussed, such as adjustments to the cooling rate and the influence of the electron beam on the antiproton beam lifetime.

  8. Status of the R&D Towards Electron Cooling of RHIC

    SciTech Connect

    A. Favale; D. Holmes; J.J. Sredniawski; Hans Bluem; M.D. Cole; J. Rathke; T. Schultheiss; A.M.M. Todd; V.V. Parkhomchuk; V.B. Reva; J. Alduino; D.S. Barton; Dana Richard Beavis; I. Ben-Zvi; Michael Blaskiewicz; J.M. Brennan; Andrew Burrill; Rama Calaga; P. Cameron; X. Chang; K.A. Drees; A.V. Fedotov; W. Fischer; G. Ganetis; D.M. Gassner; J.G. Grimes; Hartmut Hahn; L.R. Hammons; A. Hershcovitch; H.C. Hseuh; D. Kayran; J. Kewisch; R.F. Lambiase; D.L. Lederle; Vladimir Litvinenko; C. Longo; W.W. MacKay; G.J. Mahler; G.T. McIntyre; W. Meng; B. Oerter; C. Pai; George Parzen; D. Pate; D. Phillips; S.R. Plate; Eduard Pozdeyev; Triveni Rao; J. Reich; Thomas Roser; A.G. Ruggiero; T. Russo; C. Schultheiss; Z. Segalov; J. Smedley; K. Smith; T. Tallerico; S. Tepikian; R. Than; R.J. Todd; Dejan Trbojevic; J.E. Tuozzolo; P. Wanderer; G. WANG; D. Weiss; Q. Wu; Kin Yip; A. Zaltsman; A. Burov; S. Nagaitsev; L.R. Prost; A.O. Sidorin; A.V. Smirnov; Yaroslav Derbenev; Peter Kneisel; John Mammosser; H. Phillips; Joseph Preble; Charles Reece; Robert Rimmer; Jeffrey Saunders; Mircea Stirbet; Haipeng Wang; A.V. Aleksandrov; D.L. Douglas; Y.W. Kang; D.T. Abell; G.I. Bell; David L. Bruhwiler; R. Busby; John R. Cary; D.A. Dimitrov; P. Messmer; Vahid Houston Ranjbar; D.S. Smithe; A.V. Sobol; P. Stoltz

    2007-08-01

    The physics interest in a luminosity upgrade of RHIC requires the development of a cooling-frontier facility. Detailed cooling calculations have been made to determine the efficacy of electron cooling of the stored RHIC beams. This has been followed by beam dynamics simulations to establish the feasibility of creating the necessary electron beam. Electron cooling of RHIC at collisions requires electron beam energy up to about 54 MeV at an average current of between 50 to 100 mA and a particularly bright electron beam. The accelerator chosen to generate this electron beam is a superconducting Energy Recovery Linac (ERL) with a superconducting RF gun with a laser-photocathode. An intensive experimental R&D program engages the various elements of the accelerator: Photocathodes of novel design, superconducting RF electron gun of a particularly high current and low emittance, a very high-current ERL cavity and a demonstration ERL using these components.

  9. The nonextensive parameter for nonequilibrium electron gas in an electromagnetic field

    SciTech Connect

    Yu, Haining; Du, Jiulin

    2014-11-15

    The nonextensive parameter for nonequilibrium electron gas of the plasma in an electromagnetic field is studied. We exactly obtained an expression of the q-parameter based on Boltzmann kinetic theories for plasmas, where Coulombian interactions and Lorentz forces play dominant roles. We show that the q-parameter different from unity is related by an equation to temperature gradient, electric field strength, magnetic induction as well as overall bulk velocity of the gas. The effect of the magnetic field on the q-parameter depends on the overall bulk velocity. Thus the q-parameter for the electron gas in an electromagnetic field represents the nonequilibrium nature or nonisothermal configurations of the plasma with electromagnetic interactions. - Highlights: • An expression of the q-parameter is obtained for nonequilibrium plasma with electromagnetic interactions. • The q-parameter is related to temperature gradient, electric field strength, magnetic induction as well as overall bulk velocity of the plasma. • The q-parameter represents the nonequilibrium nature of the complex plasma with electromagnetic interactions.

  10. Numerical simulation of electromagnetic emissions in the solar wind plasma with non-thermal electron distribution

    NASA Astrophysics Data System (ADS)

    Khalilpour, H.

    2014-09-01

    Dynamics of fundamental and second harmonic electromagnetic emissions are simulated in the solar wind plasma in the presence of non-thermal electron distribution function in which primary Langmuir waves are driven by an electron beam. The electron velocity distribution function is separated into two distributions representing the distribution of the ambient electrons (Maxwellian) and the suprathermal electrons (non-thermal electrons). The effects of the non-thermal electrons on the generation of primary Langmuir waves, emission rates of the fundamental (F) and harmonic waves (H) and their distributions are investigated. The both of the F and H emissions are sensitive to the characterizes of the non-thermal electrons. It is found that in the presence of non-thermal electrons the production of the Langmuir waves decreases and consequently the levels of fundamental and second harmonic waves are reduced. The emission rate of the fundamental transverse waves decreases and its peak moves slightly toward smaller wave-numbers.

  11. Guiding and collimating fast electron beam by the quasi-static electromagnetic field array

    SciTech Connect

    Wang, J.; Zhao, Z. Q.; He, W. H.; Dong, K. G.; Wu, Y. C.; Zhu, B.; Zhang, T. K.; Zhang, B.; Zhang, Z. M.; Gu, Y. Q.; Cao, L. H.

    2014-10-15

    A guidance and collimation scheme for fast electron beam in a traverse periodic quasi-static electromagnetic field array is proposed with the semi-analytic method and the particle-in-cell simulation. The sheath electric fields on the surfaces of nanowires and the magnetic fields around the nanowires form a traverse periodic quasi-static electromagnetic field array. Therefore, most of the fast electrons are confined at the nanowire surfaces and transport forward. More importantly, due to the divergent property of the beams, the magnitudes of the generated fields decrease with the target depth. The lateral momenta of the electrons convert into the forward momenta through Lorenz force, and they cannot recover their initial values. Therefore, the fast electrons can be guided and collimated efficiently in the gaps between the nanowires. In our particle-in-cell simulations, the observed guiding efficiency exceeds 80% compared with the reference target.

  12. Electromagnetic waves destabilized by runaway electrons in near-critical electric fields

    SciTech Connect

    Komar, A.; Pokol, G. I.; Fueloep, T.

    2013-01-15

    Runaway electron distributions are strongly anisotropic in velocity space. This anisotropy is a source of free energy that may destabilize electromagnetic waves through a resonant interaction between the waves and the energetic electrons. In this work, we investigate the high-frequency electromagnetic waves that are destabilized by runaway electron beams when the electric field is close to the critical field for runaway acceleration. Using a runaway electron distribution appropriate for the near-critical case, we calculate the linear instability growth rate of these waves and conclude that the obliquely propagating whistler waves are most unstable. We show that the frequencies, wave numbers, and propagation angles of the most unstable waves depend strongly on the magnetic field. Taking into account collisional and convective damping of the waves, we determine the number density of runaways that is required to destabilize the waves and show its parametric dependences.

  13. Electrostatic and electromagnetic gyroharmonic emissions due to energetic electrons in magnetospheric plasma

    NASA Technical Reports Server (NTRS)

    Curtis, S. A.; Wu, C. S.

    1979-01-01

    The paper derives the growth rates and growth lengths of the electrostatic emission for spatially homogeneous and inhomogeneous energetic electrons, and numerically evaluates the growth rate and growth length spectra for several parameter sets representative of magnetospheric plasmas. In addition, the growth rates are derived for the case of electromagnetic emission modeled by the ordinary mode. The numerical results of the electromagnetic and electrostatic cases are compared with observations made by satellites in the earth's magnetosphere. It is concluded that the electrostatic gyroharmonic excitation is possible without the cold composition of plasma which is often postulated in the existing literature.

  14. Nonlinear propagation of broadband intense electromagnetic waves in an electron-positron plasma

    SciTech Connect

    Marklund, M.; Eliasson, B.; Shukla, P. K.

    2006-08-15

    A kinetic equation describing the nonlinear evolution of intense electromagnetic pulses in electron-positron (e-p) plasmas is presented. The modulational instability is analyzed for a relativistically intense partially coherent pulse, and it is found that the modulational instability is inhibited by the spectral pulse broadening. A numerical study for the one-dimensional kinetic photon equation is presented. Computer simulations reveal a Fermi-Pasta-Ulam-type recurrence phenomenon for localized broadband pulses. The results should be of importance in understanding the nonlinear propagation of broadband intense electromagnetic pulses in e-p plasmas in laser-plasma systems as well as in astrophysical plasma settings.

  15. A robust platform cooled by superconducting electronic refrigerators

    NASA Astrophysics Data System (ADS)

    Nguyen, H. Q.; Meschke, M.; Pekola, J. P.

    2015-01-01

    A biased tunnel junction between a superconductor and a normal metal can cool the latter electrode. Based on a recently developed cooler with high power and superior performance, we have integrated it with a dielectric silicon nitride membrane, and cooled phonons from 305 mK down to 200 mK. Without perforation and covered under a thin alumina layer, the membrane is rigorously transformed into a cooling platform that is robust and versatile for multiple practical purposes. We discussed our results and possibilities to further improve the device.

  16. Evaluation of Electromagnetic Fields in a Hospital for Safe Use of Electronic Medical Equipment.

    PubMed

    Ishida, Kai; Fujioka, Tomomi; Endo, Tetsuo; Hosokawa, Ren; Fujisaki, Tetsushi; Yoshino, Ryoji; Hirose, Minoru

    2016-03-01

    Establishment of electromagnetic compatibility is important in use of electronic medical equipment in hospitals. To evaluate the electromagnetic environment, the electric field intensity induced by electromagnetic radiation in broadcasting spectra coming from outside the hospital was measured in a new hospital building before any patients visited the hospital and 6 months after the opening of the hospital. Various incoming radio waves were detected on the upper floors, with no significant difference in measured levels before and after opening of the hospital. There were no cellphone terminal signals before the hospital opened, but these signals were strongly detected at 6 months thereafter. Cellphone base stations signals were strongly detected on the upper floors, but there were no signals at most locations in the basement and in the center of the building on the lower floors. A maximum electrical intensity of 0.28 V/m from cellphone base stations (2.1 GHz) was detected at the south end of the 2nd floor before the hospital opened. This value is lower than the EMC marginal value for general electronic medical equipment specified in IEC 60601-1-2 (3 V/m). Therefore, electromagnetic interference with electronic medical equipment is unlikely in this situation. However, cellphone terminal signals were frequently detected in non-base station signal areas. This is a concern, and understanding signal strength from cellphone base stations at a hospital is important for promotion of greater safety. PMID:26643076

  17. Enhanced radiative recombination of U92+ ions with cooling electrons for the K-shell

    NASA Astrophysics Data System (ADS)

    Banaś, D.; Beyer, H. F.; Bosch, F.; Brandau, C.; Böhm, S.; Chatterjee, S.; Czarnota, M.; Dousse, J.-Cl; Gumberidze, A.; Hagmann, S.; Kozhuharov, C.; Liesen, D.; Mokler, P. H.; Müller, A.; Kumar, A.; Pajek, M.; Reuschl, R.; Schmidt, E. W.; Sierpowski, D.; Spillmann, U.; Surzhykov, A.; Stöhlker, Th; Szlachetko, J.; Tashenov, S.; Trotsenko, S.; Verma, P.; Warczak, A.

    2012-11-01

    Observed enhancement of K-shell radiative recombination (RR) of bare uranium ions with cooling electrons is interpreted in terms of of distant transverse collisions in magnetized electron-cooler plasma described within the semiclassical geometrical model (SGM), which was recently proposed. The Monte Carlo simulations based on the proposed approach explains the enhancement measured in RR of U92+ ions with cooling electrons for the K-shell.

  18. STATUS OF THE RESEARCH AND DEVELOPMENT TOWARDS ELECTRON COOLING OF RHIC

    SciTech Connect

    BEN-ZVI,I.; OZAKI, T.; YOSHIDA, T.; NANKAWA, T.; KOZAI, N.; SAKAMOTO, F.; SUZUKI, Y.

    2007-06-25

    The physics interest in a luminosity upgrade of RHIC requires the development of a cooling-frontier facility. Detailed calculations were made of electron cooling of the stored RHIC beams. This has been followed by beam dynamics simulations to establish the feasibility of creating the necessary electron beam. The electron beam accelerator will be a superconducting Energy Recovery Linac (ERL). An intensive experimental R&D program engages the various elements of the accelerator, as described by 24 contributions to the 2007 PAC.

  19. Inhibition of electron thermal conduction by electromagnetic instabilities. [in stellar coronas

    NASA Technical Reports Server (NTRS)

    Levinson, Amir; Eichler, David

    1992-01-01

    Heat flux inhibition by electromagnetic instabilities in a hot magnetized plasma is investigated. Low-frequency electromagnetic waves become unstable due to anisotropy of the electron distribution function. The chaotic magnetic field thus generated scatters the electrons with a specific effective mean free path. Saturation of the instability due to wave-wave interaction, nonlinear scattering, wave propagation, and collisional damping is considered. The effective mean free path is found self-consistently, using a simple model to estimate saturation level and scattering, and is shown to decrease with the temperature gradient length. The results, limited to the assumptions of the model, are applied to astrophysical systems. For some interstellar clouds the instability is found to be important. Collisional damping stabilizes the plasma, and the heat conduction can be dominated by superthermal electrons.

  20. Modulation of a compressional electromagnetic wave in a magnetized electron-positron quantum plasma.

    PubMed

    Amin, M R

    2015-09-01

    Amplitude modulation of a compressional electromagnetic wave in a strongly magnetized electron-positron pair plasma is considered in the quantum magnetohydrodynamic regime. The important ingredients of this study are the inclusion of the external strong magnetic field, Fermi quantum degeneracy pressure, particle exchange potential, quantum diffraction effects via the Bohm potential, and dissipative effect due to collision of the charged carriers. A modified-nonlinear Schödinger equation is developed for the compressional magnetic field of the electromagnetic wave by employing the standard reductive perturbation technique. The linear and nonlinear dispersions of the electromagnetic wave are discussed in detail. For some parameter ranges, relevant to dense astrophysical objects such as the outer layers of white dwarfs, neutron stars, and magnetars, etc., it is found that the compressional electromagnetic wave is modulationally unstable and propagates as a dissipated electromagnetic wave. It is also found that the quantum effects due to the particle exchange potential and the Bohm potential are negligibly small in comparison to the effects of the Fermi quantum degeneracy pressure. The numerical results on the growth rate of the modulation instability is also presented. PMID:26465574

  1. Modulational instability of electromagnetic electron-cyclotron wave packets in the magnetosphere with non-Maxwellian electron distribution

    SciTech Connect

    Abbasi, H.; Hakimi Pajouh, H.

    2008-09-15

    The satellite observations of the magnetosphere in the low-frequency ion dynamics revealed several facts: (1) localized structures for electric field signal parallel to the magnetic field; (2) anisotropy for the electron velocity distribution such that T{sub perpendicular}<electrons. Based on these evidences, a nonlinear model is presented to develop the electromagnetic electron-cyclotron (EMEC) theory to the non-Maxwellian plasmas. Then, the modulational instability analysis of EMEC waves is investigated.

  2. Vibrational and rotational cooling of electrons by water vapor. [in cometary ionospheres

    NASA Technical Reports Server (NTRS)

    Cravens, T. E.; Korosmezey, A.

    1986-01-01

    The cooling of electrons by vibrational and rotational excitation of water molecules plays an important role in the thermal balance of electrons in cometary ionospheres. The energy-loss function for rotational excitation and deexcitation of H2O by electron impact is calculated theoretically. The rotational cooling rate is calculated using this loss function for a wide range of electron and neutral temperatures. The vibrational cooling rate is calculated using measured values of electron-impact vibrational excitation cross sections. Analytical formulas are provided for some of the cooling rates. The interaction of ions with H2O molecules is also discussed, and a formula is suggested for the momentum-transfer collision frequency.

  3. Single pass electron beam cooling of gold ions between EBIS LINAC and booster is theoretically possible!

    SciTech Connect

    Hershcovitch, A.

    2011-01-01

    Electron beam cooling is examined as an option to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster. Electron beam parameters are based on experimental data (obtained at BNL) of electron beams extracted from a plasma cathode. Many issues, regarding a low energy high current electron beam that is needed for electron beam cooling to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster, were examined. Computations and some experimental data indicate that none of these issues is a show stopper. Preliminary calculations indicate that single pass cooling is feasible; momentum spread can be reduced by more than an order of magnitude in about one meter. Hence, this option cooling deserves further more serious considerations.

  4. SRF photoinjector for proof-of-principle experiment of coherent electron cooling at RHIC

    SciTech Connect

    Kayran D.; Belomestnykh, S.; Ben-Zvi, I.; Brutus, J.C.; et al

    2012-05-20

    Coherent Electron Cooling (CEC) based on Free Electron Laser (FEL) amplifier promises to be a very good way to cool protons and ions at high energies. A proof of principle experiment to demonstrate cooling at 40 GeV/u is under construction at BNL. One of possible sources to provide sufficient quality electron beam for this experiment is a SRF photoinjector. In this paper we discuss design and simulated performance of the photoinjector based on existing 112 MHz SRF gun and newly designed single-cavity SRF linac operating at 704 MHz.

  5. EXTERNAL COMPTON EMISSION IN BLAZARS OF NONLINEAR SYNCHROTRON SELF-COMPTON-COOLED ELECTRONS

    SciTech Connect

    Zacharias, Michael; Schlickeiser, Reinhard E-mail: rsch@tp4.rub.de

    2012-12-20

    The origin of the high-energy component in spectral energy distributions (SEDs) of blazars is still something of a mystery. While BL Lac objects can be successfully modeled within the one-zone synchrotron self-Compton (SSC) scenario, the SED of low-peaked flat spectrum radio quasars is more difficult to reproduce. Their high-energy component needs the abundance of strong external photon sources, giving rise to stronger cooling via the inverse Compton (IC) channel, and thus to a powerful component in the SED. Recently, we have been able to show that such a powerful inverse Compton component can also be achieved within the SSC framework. This, however, is only possible if the electrons cool by SSC, which results in a nonlinear process, since the cooling depends on an energy integral over the electrons. In this paper, we aim to compare the nonlinear SSC framework with the external Compton (EC) output by calculating analytically the EC component with the underlying electron distribution being either linearly or nonlinearly cooled. Due to the additional linear cooling of the electrons with the external photons, higher number densities of electrons are required to achieve nonlinear cooling, resulting in more powerful IC components. If the electrons initially cool nonlinearly, the resulting SED can exhibit a dominant SSC over the EC component. However, this dominance depends strongly on the input parameters. We conclude that, with the correct time-dependent treatment, the SSC component should be taken into account in modeling blazar flares.

  6. A Unique Approach to Power Electronics and Motor Cooling in a Hybrid Electric Vehicle Environment

    SciTech Connect

    Ayers, Curtis William; Hsu, John S; Lowe, Kirk T; Conklin, Jim

    2007-01-01

    An innovative system for cooling the power electronics of hybrid electric vehicles is presented. This system uses a typical automotive refrigerant R-134a (1,1,1,2 tetrafluoroethane) as the cooling fluid in a system that can be used as either part of the existing vehicle passenger air conditioning system or separately and independently of the existing air conditioner. Because of the design characteristics, the cooling coefficient of performance is on the order of 40. Because liquid refrigerant is used to cool the electronics directly, high heat fluxes can result while maintaining an electronics junction temperature at an acceptable value. In addition, an inverter housing that occupies only half the volume of a conventional inverter has been designed to take advantage of this cooling system. Planned improvements should result in further volume reductions while maintaining a high power level.

  7. Effect of electron density profile on power absorption of high frequency electromagnetic waves in plasma

    SciTech Connect

    Xi Yanbin; Liu Yue

    2012-07-15

    Considering different typical electron density profiles, a multi slab approximation model is built up to study the power absorption of broadband (0.75-30 GHz) electromagnetic waves in a partially ionized nonuniform magnetized plasma layer. Based on the model, the power absorption spectra for six cases are numerically calculated and analyzed. It is shown that the absorption strongly depends on the electron density fluctuant profile, the background electron number density, and the collision frequency. A potential optimum profile is also analyzed and studied with some particular parameters.

  8. 3D electromagnetic simulation of spatial autoresonance acceleration of electron beams

    NASA Astrophysics Data System (ADS)

    Dugar-Zhabon, V. D.; González, J. D.; Orozco, E. A.

    2016-02-01

    The results of full electromagnetic simulations of the electron beam acceleration by a TE 112 linear polarized electromagnetic field through Space Autoresonance Acceleration mechanism are presented. In the simulations, both the self-sustaned electric field and selfsustained magnetic field produced by the beam electrons are included into the elaborated 3D Particle in Cell code. In this system, the space profile of the magnetostatic field maintains the electron beams in the acceleration regime along their trajectories. The beam current density evolution is calculated applying the charge conservation method. The full magnetic field in the superparticle positions is found by employing the trilinear interpolation of the mesh node data. The relativistic Newton-Lorentz equation presented in the centered finite difference form is solved using the Boris algorithm that provides visualization of the beam electrons pathway and energy evolution. A comparison between the data obtained from the full electromagnetic simulations and the results derived from the motion equation depicted in an electrostatic approximation is carried out. It is found that the self-sustained magnetic field is a factor which improves the resonance phase conditions and reduces the beam energy spread.

  9. Cyclotron-undulator cooling of a free-electron-laser beam

    SciTech Connect

    Bandurkin, I. V.; Kuzikov, S. V.; Savilov, A. V.

    2014-08-18

    We propose methods of fast cooling of an electron beam, which are based on wiggling of particles in an undulator in the presence of an axial magnetic field. We use a strong dependence of the axial electron velocity on the oscillatory velocity, when the electron cyclotron frequency is close to the frequency of electron wiggling in the undulator field. The abnormal character of this dependence (when the oscillatory velocity increases with the increase of the input axial velocity) can be a basis of various methods for fast cooling of moderately relativistic (several MeV) electron beams.

  10. Kinetic Electron Closures for Electromagnetic Simulation of Drift and Shear-Alfven Waves (II)

    SciTech Connect

    Cohen, B I; Dimits, A M; Nevins, W M; Chen, Y; Parker, S

    2001-10-11

    An electromagnetic hybrid scheme (fluid electrons and gyrokinetic ions) is elaborated in example calculations and extended to toroidal geometry. The scheme includes a kinetic electron closure valid for {beta}{sub e} > m{sub e}/m{sub i} ({beta}{sub e} is the ratio of the plasma electron pressure to the magnetic field energy density). The new scheme incorporates partially linearized ({delta}f) drift-kinetic electrons whose pressure and number density moments are used to close the fluid momentum equation for the electron fluid (Ohm's law). The test cases used are small-amplitude kinetic shear-Alfven waves with electron Landau damping, the ion-temperature-gradient instability, and the collisionless drift instability (universal mode) in an unsheared slab as a function of the plasma {beta}{sub e}. Attention is given to resolution and convergence issues in simulations of turbulent steady states.

  11. Stability of relativistic electron trapping by strong whistler or electromagnetic ion cyclotron waves

    NASA Astrophysics Data System (ADS)

    Artemyev, A. V.; Mourenas, D.; Agapitov, O. V.; Vainchtein, D. L.; Mozer, F. S.; Krasnoselskikh, V.

    2015-08-01

    In the present paper, we investigate the trapping of relativistic electrons by intense whistler-mode waves or electromagnetic ion cyclotron waves in the Earth's radiation belts. We consider the non-resonant impact of additional, lower amplitude magnetic field fluctuations on the stability of electron trapping. We show that such additional non-resonant fluctuations can break the adiabatic invariant corresponding to trapped electron oscillations in the effective wave potential. This destruction results in a diffusive escape of electrons from the trapped regime of motion and thus can lead to a significant reduction of the efficiency of electron acceleration. We demonstrate that when energetic electrons are trapped by intense parallel or very oblique whistler-mode waves, non-resonant magnetic field fluctuations in the whistler-mode frequency range with moderate amplitudes around 3 -15 pT (much less intense than the primary waves) can totally disrupt the trapped motion. However, the trapping of relativistic electrons by electromagnetic ion cyclotron waves is noticeably more stable. We also discuss how the proposed approach can be used to estimate the effects of wave amplitude modulations on the motion of trapped particles.

  12. Electronic Spectra of the Jet-Cooled Acetaminophen

    NASA Astrophysics Data System (ADS)

    Lee, Seung Jun; Min, Ahreum; Kim, Yusic; Choi, Myong Yong; Chang, Jinyoung; Lee, Sang Hak; Kim, Seong Keun

    2010-06-01

    Resonant two-photon ionization (R2PI), laser induced fluorescence (LIF) and UV-UV double resonance spectra of the jet-cooled acetaminophen, widely used as a pain reliever and fever reducer, were obtained in the gas phase. Conformational characterizations for acetaminophen will be presented with an aid of spectroscopic techniques and DFT B3LYP calculations.

  13. Equations of motion for a free-electron laser with an electromagnetic pump field and an axial electrostatic field

    NASA Technical Reports Server (NTRS)

    Hiddleston, H. R.; Segall, S. B.

    1981-01-01

    The equations of motion for a free-electron laser (FEL) with an electromagnetic pump field and a static axial electric field are derived using a Hamiltonian formalism. Equations governing the energy transfer between the electron beam and each of the electromagnetic fields are given, and the phase shift for each of the electromagnetic fields is derived from a linearized Maxwell wave equation. The relation between the static axial electric field and the resonant phase is given. Laser gain and the fraction of the electron energy converted to photon energy are determined using a simplified resonant particle model. These results are compared to those of a more exact particle simulation code.

  14. Evidence of local power deposition and electron heating by a standing electromagnetic wave in electron-cyclotron-resonance plasma.

    PubMed

    Durocher-Jean, A; Stafford, L; Dap, S; Makasheva, K; Clergereaux, R

    2014-09-01

    Microwave plasmas excited at electron-cyclotron resonance were studied in the 0.5-15 mTorr pressure range. In contrast with low-limit pressure conditions where the plasma emission highlights a fairly homogeneous spatial structure, a periodic spatial modulation (period ∼6.2 cm) appeared as pressure increased. This feature is ascribed to a local power deposition (related to the electron density) due to the presence of a standing electromagnetic wave created by the feed electromagnetic field (2.45 GHz) in the cavity formed by the reactor walls. Analysis of the electron energy probability function by Langmuir probe and optical emission spectroscopy further revealed the presence of a high-energy tail that showed strong periodic spatial modulation at higher pressure. The spatial evolution of the electron density and of the characteristic temperature of these high-energy electrons coincides with the nodes (maximum) and antinodes (minimum) of the standing wave. These spatially-modulated power deposition and electron heating mechanisms are then discussed. PMID:25314546

  15. One dimensional electromagnetic simulation of multiple electron beams propagating in space plasmas

    NASA Astrophysics Data System (ADS)

    Simões Junior, Fernando; Virgínia Alves, Maria

    2010-05-01

    It is by now well known that electron beams play an important role in generating radio emissions such as type II and type III radio bursts, commonly observed by spacecraft in the interplanetary medium. Electron beams streaming back from Earth's bow shock into the solar wind have been proposed as a possible source for the electron plasma waves observed by spacecraft in the electron foreshock. Recent observations suggest that during the natural evolution of the foreshock plasma, multiple electron beams could be injected over a period of time, losing their individual identity to coalesce into a single beam. In this work we use an electromagnetic PIC code ``KEMPO 1D, adapted'' to simulate two electron beams which are injected into a plasma at different times. The first beam disturbs the background plasma and generates Langmuir waves by electron beam-plasma interaction. Subsequently, another beam is inserted into the system and interacts with the first one and with the driven Langmuir waves to produce electromagnetic radiation. The results of our simulation show that the first beam can produce electrostatic harmonics of the plasma frequency while the second beam intensifies the emission at the harmonics that are produced by the first one. The behavior of the second beam is strongly determined by the pre-existing Langmuir wave electric fields. The simulations also show, as a result of the interaction between both beams, a clear nonlinear frequency shift of the harmonic modes, as well as an increasing of electromagnetic and kinetic energies of the wave-particle system.

  16. One-dimenssional electromagnetic simulation of multiple electron beams propagating in space plasmas

    NASA Astrophysics Data System (ADS)

    Simões, F. J. R.; Alves, M. V.; Gaelzer, R.

    2010-06-01

    It is by now well known that electron beams play an important role in generating radio emissions such as type II and type III radio bursts, commonly observed by spacecraft in the interplanetary medium. Electron beams streaming back from Earth's bow shock into the solar wind have been proposed as a possible source for the electron plasma waves observed by spacecraft in the electron foreshock. Recent observations suggest that during the natural evolution of the foreshock plasma, multiple electron beams could be injected over a period of time, losing their individual identity to coalesce into a single beam. In this work, we use an electromagnetic particle-in-cell (PIC) code “KEMPO 1D, adapted” to simulate two electron beams that are injected into a plasma at different times. The first beam disturbs the background plasma and generates Langmuir waves by electron beam-plasma interaction. Subsequently, another beam is inserted into the system and interacts with the first one and with the driven Langmuir waves to produce electromagnetic radiation. The results of our simulation show that the first beam can produce electrostatic harmonics of the plasma frequency, while the second beam intensifies the emission at the harmonics that is produced by the first one. The behavior of the second beam is strongly determined by the preexisting Langmuir wave electric fields. The simulations also show, as a result of the interaction between both beams, a clear nonlinear frequency shift of the harmonic modes as well as an increase of electromagnetic and kinetic energies of the wave-particle system.

  17. Electromagnetic levitation facility incorporating electron beam. [for vacuum heating and melting

    NASA Technical Reports Server (NTRS)

    Wouch, G.; Okress, E. C.; Frost, R. T.; Rutecki, D. J.

    1975-01-01

    An electromagnetic levitation apparatus incorporating an electron beam for auxiliary heating and melting has been developed for experiments on containerless vacuum purification and undercooled solidification of high melting materials. Stable levitation of 10-g specimens of molten tungsten has been achieved and a variety of containerless solidification experiments is being performed, including pure polycrystalline castings and single tungsten crystals grown from the undercooled levitated melts.

  18. Experimental search for the electron electric dipole moment with laser cooled francium atoms

    NASA Astrophysics Data System (ADS)

    Inoue, T.; Ando, S.; Aoki, T.; Arikawa, H.; Ezure, S.; Harada, K.; Hayamizu, T.; Ishikawa, T.; Itoh, M.; Kato, K.; Kawamura, H.; Uchiyama, A.; Aoki, T.; Asahi, K.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Nataraj, H. S.; Sato, T.; Shimizu, Y.; Wakasa, T.; Yoshida, H. P.; Yoshimi, A.; Sakemi, Y.

    2015-04-01

    A laser cooled heavy atom is one of the candidates to search for the permanent electric dipole moment (EDM) of the electron due to the enhancement mechanism and its long coherence time. The laser cooled francium (Fr) factory has been constructed to perform the electron EDM search at the Cyclotron and Radioisotope Center, Tohoku University. The present status of Fr production and the EDM measurement system is presented.

  19. Propagation of electromagnetic waves in the plasma near electron cyclotron resonance: Undulator-induced transparency

    SciTech Connect

    Shvets, G.; Tushentsov, M.; Tokman, M.D.; Kryachko, A.

    2005-05-15

    Propagation of electromagnetic waves in magnetized plasma near the electron cyclotron frequency can be strongly modified by adding a weak magnetic undulator. For example, both right- and left-hand circularly polarized waves can propagate along the magnetic field without experiencing resonant absorption. This effect of entirely eliminating electron cyclotron heating is referred to as the undulator-induced transparency (UIT) of the plasma, and is the classical equivalent of the well-known quantum mechanical effect of electromagnetically induced transparency. The basics of UIT are reviewed, and various ways in which UIT can be utilized to achieve exotic propagation properties of electromagnetic waves in plasmas are discussed. For example, UIT can dramatically slow down the waves' group velocity, resulting in the extreme compression of the wave energy in the plasma. Compressed waves are polarized along the propagation direction, and can be used for synchronous electron or ion acceleration. Strong coupling between the two wave helicities are explored to impart the waves with high group velocities {partial_derivative}{omega}/{partial_derivative}k for vanishing wave numbers k. Cross-helicity coupling for realistic density and magnetic field profiles are examined using a linearized fluid code, particle-in-cell simulations, and ray-tracing WKB calculations.

  20. High-Current ERL-Based Electron Cooling System for RHIC

    SciTech Connect

    Ben-Zvi, Ilan

    2006-03-20

    The design of an electron cooler must take into account both electron beam dynamics issues as well as the electron cooling physics. Research towards high-energy electron cooling of RHIC is in its 3rd year at Brookhaven National Laboratory. The luminosity upgrade of RHIC calls for electron cooling of various stored ion beams, such as 100 GeV/A gold ions at collision energies. The necessary electron energy of 54 MeV is clearly out of reach for DC accelerator system of any kind. The high energy also necessitates a bunched beam, with a high electron bunch charge, low emittance and small energy spread. The Collider-Accelerator Department adopted the Energy Recovery Linac (ERL) for generating the high-current, high-energy and high-quality electron beam. The RHIC electron cooler ERL will use four Superconducting RF (SRF) 5-cell cavities, designed to operate at ampere-class average currents with high bunch charges. The electron source will be a superconducting, 705.75 MHz laser-photocathode RF gun, followed up by a superconducting Energy Recovery Linac (ERL). An R and D ERL is under construction to demonstrate the ERL at the unprecedented average current of 0.5 amperes. Beam dynamics performance and luminosity enhancement are described for the case of magnetized and non-magnetized electron cooling of RHIC.

  1. The effect of superluminal phase velocity on electron acceleration in a powerful electromagnetic wave

    NASA Astrophysics Data System (ADS)

    Robinson, A. P. L.; Arefiev, A. V.; Khudik, V. N.

    2015-08-01

    In this paper, we examine the effect that electromagnetic dispersion has on the motion of an electron in a relativistically strong plane wave. We obtain an analytic solution for the electron momentum and check this solution against direct numerical integration of the equations of motion. The solution shows that even a relatively small difference between the phase velocity of the wave, vp, and the speed of light, c, can significantly alter the electron dynamics if the normalized wave amplitude a0 exceeds ?{2 c /(vp-c ) } . At this amplitude, the maximum longitudinal electron momentum scales only linearly with a0, as opposed to a02 . We also show that at this amplitude the impact of an accelerating longitudinal electric field and electron pre-acceleration is negated by the superluminous phase velocity of the wave. This has implications for the potential of Direct Laser Acceleration of electrons. We point out that electromagnetic dispersion can arise from both propagation in a plasma and from propagating the laser in what is effectively a wave-guiding structure, and that this latter source of dispersion is likely to be more significant.

  2. Combined Laser and Electron Cooling of Bunched C3+ Ion Beams at the Storage Ring ESR

    SciTech Connect

    Schramm, U.; Bussmann, M.; Habs, D.; Kuehl, T.; Beller, P.; Franzke, B.; Nolden, F.; Steck, M.; Saathoff, G.; Reinhardt, S.; Karpuk, S.

    2006-03-20

    We report on first laser cooling studies of bunched beams of triply charged carbon ions stored at an energy of 1.46 GeV at the ESR (GSI). Despite for the high beam energy and charge state laser cooling provided a reduction of the momentum spread of one order of magnitude in space-charge dominated bunches as compared to electron cooling. For ion currents exceeding 10 {mu}A intra-beam-scattering losses could not be compensated by the narrow band laser system presently in use. Yet, no unexpected problems occurred encouraging the envisaged extension of the laser cooling to highly relativistic beams. At ESR, especially the combination with modest electron cooling provided three-dimensionally cold beams in the plasma parameter range of unity, where ordering effects can be expected and a still unexplained signal reduction of the Schottky signal is observed.

  3. Effects of a nonlinear damping force in synchrotrons with electron cooling

    SciTech Connect

    Caussyn, D.D.; Ball, M.; Budnick, J.; East, G.; Ellison, M.; Hamilton, B.; Hedblom, K.; Kang, X.; Lee, S.Y.; Li, D.; Liu, J.Y.; Ng, K.Y.; Riabko, A.; Wang, L.; Wang, Y.

    1995-05-01

    The longitudinal dynamics of a stored proton beam bunch, under the influence of a nonlinear damping force produced by electron cooling, was studied experimentally. The effect of the nonlinear damping force was explored by varying the relative velocity between the cooling electrons and the stored protons. Maintained longitudinal oscillations developed, which grew rapidly once a critical threshold in the relative velocity was exceeded. The bifurcation of a fixed point into a limit cycle is also known as a Hopf bifurcation. Comparisons of experimental data with numerical simulations and analytical calculations are made. Implications for cooled beam acceleration will be discussed.

  4. The integration of liquid cryogen cooling and cryocoolers withsuperconducting electronic systems

    SciTech Connect

    Green, Michael A.

    2003-07-09

    The need for cryogenic cooling has been a critical issuethat has kept superconducting electronic devices from reaching the marketplace. Even though the performance of many of the superconductingcircuits is superior to silicon electronics, the requirement forcryogenic cooling has put the superconducting devices at a seriousdisadvantage. This report discusses the process of refrigeratingsuperconducting devices with cryogenic liquids and small cryocoolers.Three types of cryocoolers are compared for vibration, efficiency, andreliability. The connection of a cryocooler to the load is discussed. Acomparison of using flexible copper straps to carry the heat load andusing heat pipe is shown. The type of instrumentation needed formonitoring and controlling the cooling is discussed.

  5. Observation of vacancy-induced suppression of electronic cooling in defected graphene

    NASA Astrophysics Data System (ADS)

    Wu, Xiaosong; Han, Qi; Chen, Yi; Liu, Gerui; Yu, Dapeng

    2015-03-01

    Previous studies of electron-phonon interaction in impure graphene have found that static disorder can give rise to an enhancement of electronic cooling. We investigate the effect of dynamic disorder and observe over an order of magnitude suppression of electronic cooling compared with clean graphene. The effect is stronger in graphene with more vacancies, confirming its vacancy-induced nature. The dependence of the coupling constant on the phonon temperature implies its link to the dynamics of disorder. Our study highlights the effect of disorder on electron-phonon interaction in graphene. In addition, the suppression of electronic cooling holds great promise for improving the performance of graphene-based bolometer and photo-detector devices. This work was supported by National Key Basic Research Program of China (No. 2012CB933404, 2013CBA01603) and NSFC (Project No. 11074007, 11222436, 11234001).

  6. Proton cooling in ultracold low-density electron gas

    NASA Astrophysics Data System (ADS)

    Bobrov, A. A.; Bronin, S. Y.; Manykin, E. A.; Zelener, B. B.; Zelener, B. V.; Khikhlukha, D. R.

    2015-11-01

    A sole proton energy loss processes in an electron gas and the dependence of these processes on temperature and magnetic field are studied using molecular dynamics techniques in present work. It appears that for electron temperatures less than 100 K many body collisions affect the proton energy loss and these collisions must be taken into account. The influence of a strong magnetic field on the relaxation processes is also considered in this work. Calculations were performed for electron densities 10 cm-3, magnetic field 1-3 Tesla, electron temperatures 10-50 K, initial proton energies 100-10000 K.

  7. Materials selection for electronic enclosures in space environment considering electromagnetic interference effect

    NASA Astrophysics Data System (ADS)

    Fayazbakhsh, K.; Abedian, A.

    2012-02-01

    Using low power electronic devices for space applications to reduce the mass and energy consumption has lead to electromagnetic interference (EMI) problem. Electronic enclosures are used to shield electronic devices against EMI. In the past, electromagnetic shielding has been mainly the only criteria considered in electronic enclosure design. However, there are several structural and thermal requirements for selection of shielding materials which should also be taken into account. In this research work, three quantitative materials selection methods, i.e. Digital Logic (DL), Modified Digital Logic (MDL), and Z-transformation, are employed to select the best material from among a list of candidate materials. Composite and metallic electronic enclosures are explored and the best material is selected. Z-transformation method is applicable to both of the considered case studies while DL and MDL can only be used for solving one of them. Z-transformation method ranks aluminum as the first choice among various metallic materials. The wide range of Z-transformation application and its practical results confirm the superiority of Z-transformation method over DL and MDL methods.

  8. Hybridized electromagnetic-triboelectric nanogenerator for scavenging biomechanical energy for sustainably powering wearable electronics.

    PubMed

    Zhang, Kewei; Wang, Xue; Yang, Ya; Wang, Zhong Lin

    2015-01-01

    We report a hybridized electromagnetic-triboelectric nanogenerator for highly efficient scavenging of biomechanical energy to sustainably power wearable electronics by human walking. Based on the effective conjunction of triboelectrification and electromagnetic induction, the hybridized nanogenerator, with dimensions of 5 cm × 5 cm × 2.5 cm and a light weight of 60 g, integrates a triboelectric nanogenerator (TENG) that can deliver a peak output power of 4.9 mW under a loading resistance of 6 MΩ and an electromagnetic generator (EMG) that can deliver a peak output power of 3.5 mW under a loading resistance of 2 kΩ. The hybridized nanogenerator exhibits a good stability for the output performance and a much better charging performance than that of an individual energy-harvesting unit (TENG or EMG). Furthermore, the hybridized nanogenerator integrated in a commercial shoe has been utilized to harvest biomechanical energy induced by human walking to directly light up tens of light-emitting diodes in the shoe and sustainably power a smart pedometer for reading the data of a walking step, distance, and energy consumption. A wireless pedometer driven by the hybrid nanogenerator can work well to send the walking data to an iPhone under the distance of 25 m. This work pushes forward a significant step toward energy harvesting from human walking and its potential applications in sustainably powering wearable electronics. PMID:25687592

  9. Excitation threshold of Stimulated Electromagnetic Emissions SEEs generated at pump frequency near the third electron gyroharmonic

    NASA Astrophysics Data System (ADS)

    Mahmoudian, A.; Bernhardt, P. A.; Scales, W.

    2012-12-01

    The High-Frequency Active Auroral Research Program (HAARP) in Gakona, Alaska provides effective radiated powers in the megawatt range that have allowed researchers to study many non-linear effects of wave-plasma interactions. Stimulated Electromagnetic Emission (SEE) is of interest to the ionospheric community for its diagnostic purposes. In recent HAARP heating experiments, it has been shown that during the Magnetized Stimulated Brillouin Scattering MSBS instability, the pumped electromagnetic wave may decay into an electromagnetic wave and a low frequency electrostatic wave (either ion acoustic IA wave or electrostatic ion cyclotron EIC wave). Using Stimulated Electromagnetic Emission (SEE) spectral features, side bands which extend above and below the pump frequency can yield significant diagnostics for the modified ionosphere. It has been shown that the IA wave frequency offsets can be used to measure electron temperature in the heated ionosphere and EIC wave offsets can be used as a sensitive method to determine the ion species by measuring ion mass using the ion gyro-frequency offset. The threshold of each emission line has been measured by changing the amplitude of pump wave. The experimental results aimed to show the threshold for transmitter power to excite IA wave propagating along the magnetic field lines as well as for EIC wave excited at an oblique angle relative to the background magnetic field. Another parametric decay instability studied is the ion Bernstein decay instability that has been attributed to the simultaneous parametric decay of electron Bernstein waves into multiple electron Bernstein and ion Bernstein waves. The SIB process is thought to involve mode conversion from EM to EB waves followed by parametric decay of the EB wave to multiple EB and IB waves. The parametric decay instability of ion Bernstein modes has been observed simultaneously for the first time at the third electron gyroharmonics during 2011 Summer Student Research Campaign SSRC at HAARP. The analytical results for the SIB waves at the 3rd and 4th gyroharmonics will be presented which shows good agreement with experimental data. The variation of Stimulated Electromagnetic Emission (SEE) spectrum during generation of the artificial plasma layer by HAARP transmitter has been studied during 2012 PARS campaign. It turns out that SEE features observed during the formation of artificial plasma layers may be used as a diagnostic tool to investigate the generation source of these artificial layers. Both experimental data and analytical results will be presented.

  10. Final Report for 'ParSEC-Parallel Simulation of Electron Cooling"

    SciTech Connect

    David L Bruhwiler

    2005-09-16

    The Department of Energy has plans, during the next two or three years, to design an electron cooling section for the collider ring at RHIC (Relativistic Heavy Ion Collider) [1]. Located at Brookhaven National Laboratory (BNL), RHIC is the premier nuclear physics facility. The new cooling section would be part of a proposed luminosity upgrade [2] for RHIC. This electron cooling section will be different from previous electron cooling facilities in three fundamental ways. First, the electron energy will be 50 MeV, as opposed to 100's of keV (or 4 MeV for the electron cooling system now operating at Fermilab [3]). Second, both the electron beam and the ion beam will be bunched, rather than being essentially continuous. Third, the cooling will take place in a collider rather than in a storage ring. Analytical work, in combination with the use and further development of the semi-analytical codes BETACOOL [4,5] and SimCool [6,7] are being pursued at BNL [8] and at other laboratories around the world. However, there is a growing consensus in the field that high-fidelity 3-D particle simulations are required to fully understand the critical cooling physics issues in this new regime. Simulations of the friction coefficient, using the VORPAL code [9], for single gold ions passing once through the interaction region, have been compared with theoretical calculations [10,11], and the results have been presented in conference proceedings papers [8,12,13,14] and presentations [15,16,17]. Charged particles are advanced using a fourth-order Hermite predictor corrector algorithm [18]. The fields in the beam frame are obtained from direct calculation of Coulomb's law, which is more efficient than multipole-type algorithms for less than {approx} 10{sup 6} particles. Because the interaction time is so short, it is necessary to suppress the diffusive aspect of the ion dynamics through the careful use of positrons in the simulations, and to run 100's of simulations with the same physical parameters but with different ''seeds'' for the particle loading. VORPAL can now be used to simulate other electron cooling facilities around the world, and it is also suitable for other accelerator modeling applications of direct interest to the Department of Energy. For example: (a) the Boersch effect in transport of strongly-magnetized electron beams for electron cooling sections, (b) the intrabeam scattering (IBS) effect in heavy ion accelerators, (c) the formation of crystalline beams and (d) target physics for heavy-ion fusion (HIF).

  11. Hybrid two-dimensional electron transport in self-consistent electromagnetic fields

    SciTech Connect

    Mason, R.J.; Cranfill, C.W.

    1986-02-01

    The paper outlines features of the implicit hybrid simulation code ANTHEM, which uniquely provides histories for the transport and deposition of suprathermal and thermal electrons in laser-produced plasmas. The code models two-dimensional electron transport through steep density gradients and across contiguous collisional and collisionless target regions with the plasma dynamics dominated by self-consistent EPSILON and BETA fields. ANTHEM employs separate Eulerian fluid ion and thermal electron treatments and models suprathermal electrons as either a third fluid or as a set of collisional particle-in-cell (PIC) particles. The authors outline new techniques required to obtain implicit electromagnetic fields in two spatial dimensions permitting time steps well in excess of the local plasma period. A new implicit scattering model is discussed. The utility of our approach is demonstrated with sample applications to collisional surface transport on foil targets.

  12. Control of spin dynamics in a two-dimensional electron gas by electromagnetic dressing

    NASA Astrophysics Data System (ADS)

    Pervishko, A. A.; Kibis, O. V.; Morina, S.; Shelykh, I. A.

    2015-11-01

    We solved the Schrödinger problem for a two-dimensional electron gas (2DEG) with the Rashba spin-orbit interaction in the presence of a strong high-frequency electromagnetic field (dressing field). The found eigenfunctions and eigenenergies of the problem are used to describe the spin dynamics of the dressed 2DEG within the formalism of the density matrix response function. Solving the equations of spin dynamics, we show that the dressing field can switch the spin relaxation in the 2DEG between the cases corresponding to the known Elliott-Yafet and D'yakonov-Perel' regimes. As a result, the spin properties of the 2DEG can be tuned by a high-frequency electromagnetic field. The present effect opens an unexplored way for controlling the spin with light and, therefore, forms the physical prerequisites for creating light-tuned spintronics devices.

  13. Metamorphic materials: bulk electromagnetic transitions realized in electronically reconfigurable composite media.

    PubMed

    Kyriazidou, Chryssoula A; Contopanagos, Harry F; Alexopoulos, Nicolaos G

    2006-11-01

    We present what we believe is a new class of composite electromagnetic materials characterized by the concept of metamorphism, which we define in general terms. Metamorphic materials exhibit bulk electromagnetic transitions among states characterized by distinct ranges of values of their reflection coefficient. Each such state has unique physical properties induced by the corresponding values of the reflection coefficient. We present a variety of physical realizations of the concept of metamorphic materials in microwave frequencies, showing with specific metallodielectric designs how transitions among metamorphic states can be obtained at the same frequency, for fixed material geometries, by electronic reconfigurability. We further show how a given material exhibiting certain metamorphic states at a given frequency can transform into a different combination of metamorphic states at different frequencies; i.e., metamorphic materials have a useful dispersive degree of freedom. PMID:17047724

  14. Two-dimensional electromagnetic Child-Langmuir law of a short-pulse electron flow

    SciTech Connect

    Chen, S. H.; Tai, L. C.; Liu, Y. L.; Ang, L. K.; Koh, W. S.

    2011-02-15

    Two-dimensional electromagnetic particle-in-cell simulations were performed to study the effect of the displacement current and the self-magnetic field on the space charge limited current density or the Child-Langmuir law of a short-pulse electron flow with a propagation distance of {zeta} and an emitting width of W from the classical regime to the relativistic regime. Numerical scaling of the two-dimensional electromagnetic Child-Langmuir law was constructed and it scales with ({zeta}/W) and ({zeta}/W){sup 2} at the classical and relativistic regimes, respectively. Our findings reveal that the displacement current can considerably enhance the space charge limited current density as compared to the well-known two-dimensional electrostatic Child-Langmuir law even at the classical regime.

  15. Simulations of electromagnetic emissions produced in a thin plasma by a continuously injected electron beam

    NASA Astrophysics Data System (ADS)

    Annenkov, V. V.; Timofeev, I. V.; Volchok, E. P.

    2016-05-01

    In this paper, electromagnetic emissions produced in a thin beam-plasma system are studied using two-dimensional particle-in-cell simulations. For the first time, the problem of emission generation in such a system is considered in a realistic formulation allowing for the continuous injection of a relativistic electron beam through a plasma boundary. Specific attention is given to the thin plasma case in which the transverse plasma size is comparable to the typical wavelength of beam-driven oscillations. Such a case is often implemented in laboratory beam-plasma experiments and has a number of peculiarities. Emission from a thin plasma does not require intermediate generation of the electromagnetic plasma eigenmodes, as in an infinite case, and is more similar to the regular antenna radiation. In this work, we determine how efficiently the fundamental and the second harmonic emissions can be generated in previously modulated and initially homogeneous plasmas.

  16. Electromagnetic wave instability in a relativistic electron-positron-ion plasma

    NASA Astrophysics Data System (ADS)

    Rozina, C.; Tsintsadze, N. L.; Jamil, M.; Rasheed, A.; Ali, S.

    2014-10-01

    By employing the anisotropic plasma distribution function, the stability of circularly polarized electromagnetic (EM) waves is studied in a relativistically hot electron-positron-ion (e-p-i) plasma, investigating two specific scenarios. First, linear dispersion relations associated with the transverse EM waves are analyzed in different possible frequency regimes. The expression of the aperiodic hydrodynamic instability is obtained and numerically the transverse EM modes are shown to grow exponentially. Secondly, we have found that the transverse electromagnetic wave interact with a collisionless anisotropic e-p-i plasma and damp through the nonlinear Landau damping phenomena. Taking the effects of the latter into consideration, a kinetic nonlinear Schrödinger equation is derived with local and nonlocal nonlinearities, computing the damping rates. The present work should be helpful to understand the linear and nonlinear properties of the intense EM waves in hot relativistically astrophysical plasmas, e.g., pulsars, black holes, neutron stars, etc.

  17. Electron cooling between 0.3 and 1 AU from Helios observations

    NASA Astrophysics Data System (ADS)

    Travnicek, P. M.; Sebek, O.; Stverak, S.; Hellinger, P.

    2014-12-01

    Based on Helios observations we analyze the cooling process of solar wind electrons between 0.3 and 1 AU. In the present study we assume a steady radial expansion in a Parker spiral interplanetary magnetic field and anisotropic electron velocity distribution functions. The empirical energization rates are consequently derived for both the slow and fast solar wind streams using fits of power law radial profiles to observed macroscopic electron characteristics (i.e. density, temperature and heat flux). Our results indicate that compared to protons no external heating mechanisms are required in case of solar wind electrons and the observed temperature radial gradients are simply explained by the adiabatic cooling, internal electron heat flux and energy exchange provided by electron-electron Coulomb collisions. While the energization rate in the fast solar wind is found more or less equal to zero, it is even negative in the slow wind representing thus a source of a free energy.

  18. FEL-based coherent electron cooling for high-energy hadron colliders

    SciTech Connect

    Litvinenko,V.N.; Derbenev, Y.S.

    2008-06-23

    Cooling intense high-energy hadron beams is a major challenge in modern accelerator physics. Synchrotron radiation is too feeble and two common methods--stochastic and electron cooling--are not efficient in providing significant cooling for high energy, high intensity proton colliders. In this paper they discuss a practical scheme of Coherent Electron Cooling (CeC), which promises short cooling times (below one hour) for intense proton beams in RHIC at 250 GeV or in LHC at 7 TeV. A possibility of CeC using various microwave instabilities was discussed since 1980s. In this paper, they present first evaluation of specific CeC scheme based on capabilities of present-day accelerator technology, ERLs, and high-gain Free-Electron lasers (FELs). They discuss the principles, the main limitations of this scheme and present some predictions for Coherent Electron Cooling in RHIC and the LHC operating with ions or protons, summarized in Table 1.

  19. Proof-of-Principle Experiment for FEL-based Coherent Electron Cooling

    SciTech Connect

    Litvinenko, V; Bengtsson, J; Fedotov, A V; Hao, Y; Kayran, D; Mahler, G J; Meng, W; Roser, T; Sheehy, B; Than, R; Tuozzolo, J E; Wang, G; Webb, S D; Yakimenko, V; Bell, G I; Bruhwiler, D L; Schwartz, B T; Hutton, A; Krafft, G A; Poelker, M

    2011-03-01

    Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders*. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using one of JLab’s SRF cryo-modules. In this paper, we describe the experimental setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC.

  20. Electron kinetic effects in atmosphere breakdown by an intense electromagnetic pulse.

    PubMed

    Solovyev, A A; Terekhin, V A; Tikhonchuk, V T; Altgilbers, L L

    1999-12-01

    A physical model is proposed for description of electron kinetics driven by a powerful electromagnetic pulse in the Earth's atmosphere. The model is based on a numerical solution to the Boltzmann kinetic equation for two groups of electrons. Slow electrons (with energies below a few keV) are described in a two-term approximation assuming a weak anisotropy of the electron distribution function. Fast electrons (with energies above a few keV) are described by a modified macroparticle method, taking into account the electron acceleration in the electric field, energy losses in the continuous deceleration approximation, and the multiple pitch angle scattering. The model is applied to a problem of the electric discharge in a nitrogen, which is preionized by an external gamma-ray source. It is shown that the runaway electrons have an important effect on the energy distribution of free electrons, and on the avalanche ionization rate. This mechanism might explain the observation of multiple lightning discharges observed in the Ivy-Mike thermonuclear test in the early 1950's. PMID:11970682

  1. Zitterbewegung, internal momentum and spin of the circular travelling-wave electromagnetic model electron

    NASA Astrophysics Data System (ADS)

    Asif, Malik Mohammad; Khan, Salman

    2016-02-01

    This study demonstrates that an electron, going round, with tangential velocity c , in a circle of radius equal to half the reduced Compton wavelength of the electron, has Dirac-delta-like internal momentum (u,overrightarrow{p}_{θ}). The circular momentum overrightarrow{p}_{θ} and energy u emanate from the circular Dirac-delta-type rotating monochromatic electromagnetic (EM) wave, which travels itself in another circle having radius equal to the reduced Compton wavelength of the electron. The phenomenon of Zitterbewegung and the spin of the electron are natural consequences of the model. The spin is associated with the internal circulating momentum of the electron in terms of a four-component spinor, which leads to the Dirac equation linking the EM electron model with quantum-mechanical theory. Our model accurately explains the experimental results of the electron channelling experiment (P. Catillon et al., Found. Phys. 38, 659 (2008)), in which the momentum resonance is observed at 161.784MeV/ c corresponding to a Zitterbewegung frequency of 80.874MeV/ c electron beam.

  2. Electron kinetic effects in atmosphere breakdown by an intense electromagnetic pulse

    NASA Astrophysics Data System (ADS)

    Solovyev, A. A.; Terekhin, V. A.; Tikhonchuk, V. T.; Altgilbers, L. L.

    1999-12-01

    A physical model is proposed for description of electron kinetics driven by a powerful electromagnetic pulse in the Earth's atmosphere. The model is based on a numerical solution to the Boltzmann kinetic equation for two groups of electrons. Slow electrons (with energies below a few keV) are described in a two-term approximation assuming a weak anisotropy of the electron distribution function. Fast electrons (with energies above a few keV) are described by a modified macroparticle method, taking into account the electron acceleration in the electric field, energy losses in the continuous deceleration approximation, and the multiple pitch angle scattering. The model is applied to a problem of the electric discharge in a nitrogen, which is preionized by an external gamma-ray source. It is shown that the runaway electrons have an important effect on the energy distribution of free electrons, and on the avalanche ionization rate. This mechanism might explain the observation of multiple lightning discharges observed in the Ivy-Mike thermonuclear test in the early 1950's.

  3. Electronic cooling via interlayer Coulomb coupling in multilayer epitaxial graphene

    PubMed Central

    Mihnev, Momchil T.; Tolsma, John R.; Divin, Charles J.; Sun, Dong; Asgari, Reza; Polini, Marco; Berger, Claire; de Heer, Walt A.; MacDonald, Allan H.; Norris, Theodore B.

    2015-01-01

    In van der Waals bonded or rotationally disordered multilayer stacks of two-dimensional (2D) materials, the electronic states remain tightly confined within individual 2D layers. As a result, electron–phonon interactions occur primarily within layers and interlayer electrical conductivities are low. In addition, strong covalent in-plane intralayer bonding combined with weak van der Waals interlayer bonding results in weak phonon-mediated thermal coupling between the layers. We demonstrate here, however, that Coulomb interactions between electrons in different layers of multilayer epitaxial graphene provide an important mechanism for interlayer thermal transport, even though all electronic states are strongly confined within individual 2D layers. This effect is manifested in the relaxation dynamics of hot carriers in ultrafast time-resolved terahertz spectroscopy. We develop a theory of interlayer Coulomb coupling containing no free parameters that accounts for the experimentally observed trends in hot-carrier dynamics as temperature and the number of layers is varied. PMID:26399955

  4. Nonlinear interactions between electromagnetic waves and electron plasma oscillations in quantum plasmas.

    PubMed

    Shukla, P K; Eliasson, B

    2007-08-31

    We consider nonlinear interactions between intense circularly polarized electromagnetic (CPEM) waves and electron plasma oscillations (EPOs) in a dense quantum plasma, taking into account the electron density response in the presence of the relativistic ponderomotive force and mass increase in the CPEM wave fields. The dynamics of the CPEM waves and EPOs is governed by the two coupled nonlinear Schrödinger equations and Poisson's equation. The nonlinear equations admit the modulational instability of an intense CPEM pump wave against EPOs, leading to the formation and trapping of localized CPEM wave pipes in the electron density hole that is associated with a positive potential distribution in our dense plasma. The relevance of our investigation to the next generation intense laser-solid density plasma interaction experiments is discussed. PMID:17931024

  5. Nonlinear Interactions between Electromagnetic Waves and Electron Plasma Oscillations in Quantum Plasmas

    SciTech Connect

    Shukla, P. K.; Eliasson, B.

    2007-08-31

    We consider nonlinear interactions between intense circularly polarized electromagnetic (CPEM) waves and electron plasma oscillations (EPOs) in a dense quantum plasma, taking into account the electron density response in the presence of the relativistic ponderomotive force and mass increase in the CPEM wave fields. The dynamics of the CPEM waves and EPOs is governed by the two coupled nonlinear Schroedinger equations and Poisson's equation. The nonlinear equations admit the modulational instability of an intense CPEM pump wave against EPOs, leading to the formation and trapping of localized CPEM wave pipes in the electron density hole that is associated with a positive potential distribution in our dense plasma. The relevance of our investigation to the next generation intense laser-solid density plasma interaction experiments is discussed.

  6. Nonlinear interaction of intense electromagnetic waves with a magnetoactive electron-positron-ion plasma

    SciTech Connect

    Khorashadizadeh, S. M.; Rastbood, E.; Zeinaddini Meymand, H.; Niknam, A. R.

    2013-08-15

    The nonlinear coupling between circularly polarized electromagnetic (CPEM) waves and acoustic-like waves in a magnetoactive electron-positron-ion (e-p-i) plasma is studied, taking into account the relativistic motion of electrons and positrons. The possibility of modulational instability and its growth rate as well as the envelope soliton formation and its characteristics in such plasmas are investigated. It is found that the growth rate of modulation instability increases in the case that ω{sub c}/ω<1 (ω{sub c} and ω are the electron gyrofrequency and the CPEM wave frequency, respectively) and decreases in the case that ω{sub c}/ω>1. It is also shown that in a magnetoactive e-p-i plasma, the width of bright soliton increases/decreases in case of (ω{sub c}/ω)<1/(ω{sub c}/ω)>1 by increasing the magnetic field strength.

  7. Nonlinear electromagnetic perturbations in a degenerate ultrarelativistic electron-positron plasma.

    PubMed

    El-Taibany, W F; Mamun, A A

    2012-02-01

    Nonlinear propagation of fast and slow magnetosonic perturbation modes in an ultrarelativistic, ultracold, degenerate (extremely dense) electron positron (EP) plasma (containing ultrarelativistic, ultracold, degenerate electron and positron fluids) has been investigated by the reductive perturbation method. The Alfvén wave velocity is modified due to the presence of the enthalpy correction in the fluid equations of motion. The degenerate EP plasma system (under consideration) supports the Korteweg-de Vries (KdV) solitons, which are associated with either fast or slow magnetosonic perturbation modes. It is found that the ultrarelativistic model leads to compressive (rarefactive) electromagnetic solitons corresponding to the fast (slow) wave mode. There are certain critical angles, θ(c), at which no soliton solution is found corresponding to the fast wave mode. For the slow mode, the magnetic-field intensity affects both the soliton amplitude and width. It is also illustrated that the basic features of the electromagnetic solitary structures, which are found to exist in such a degenerate EP plasma, are significantly modified by the effects of enthalpy correction, electron and positron degeneracy, magnetic-field strength, and the relativistic effect. The applications of the results in a pair-plasma medium, which occurs in many astrophysical objects (e.g., pulsars, white dwarfs, and neutron stars) are briefly discussed. PMID:22463336

  8. Regimes of the interactions of high-intensity plane electromagnetic waves with electron-ion plasmas

    SciTech Connect

    Shiryaev, O. B.

    2008-01-15

    A set of fully nonlinear equations is derived from the Maxwell equations and the electron and ion fluid dynamics in one-dimensional geometry as a model of the interactions of extremely intense plane electromagnetic waves with cold locally non-neutral electron-ion plasmas. The problem is solved for phase velocities close to the speed of light numerically and with the help of asymptotic techniques. Depending on the field magnitudes, three nonlinear regimes are found to occur in the system. At plane-wave intensities inducing relativistic electron fluid dynamics but insufficient to cause significant ion motions, the model reverts to the classic Akhiezer-Polovin problem and yields its solutions describing the nonlinear self-modulation of the electromagnetic fields in plasmas. The types of regimes sustained at field strengths entailing substantial ion dynamics are the self-modulation with a splitting of the plane-wave field spectrum into a set of closely spaced bands, and the harmonics generation with a spectrum comprising broadly distanced bands. The latter two regimes correspond to a subcritical and an overcritical range of the plasma longitudinal field potentials.

  9. Observation of core electron temperature rise in response to an edge cooling in toroidal helical plasmas

    SciTech Connect

    Tamura, N.; Inagaki, S.; Ida, K.; Shimozuma, T.; Kubo, S.; Tokuzawa, T.; Tanaka, K.; Neudatchin, S.V.; Itoh, K.; Kalinina, D.; Sudo, S.; Nagayama, Y.; Ohkubo, K.; Kawahata, K.; Komori, A.

    2005-11-15

    The first observation of a significant rise of core electron temperature in response to edge cooling in a helical plasma has been made on the Large Helical Device [O. Motojima et al., Phys. Plasmas 6, 1843 (1999)]. When the phenomenon occurs, the electron heat diffusivity in the core region is reduced abruptly without changing local parameters in the region of interest. Therefore the phenomenon can be regarded as a so-called 'nonlocal' electron temperature rise observed so far only in many tokamaks.

  10. The Hopf's limiting cycle -- A method to measure the electron cooling force

    SciTech Connect

    King-Yuen Ng

    2002-09-30

    The longitudinal phase space structure of protons in the presence of an electron drag force is studied. Depending on the relative difference in average proton velocity and electron velocity, the fixed point near the center of the phase space can be stable or unstable. When it is unstable, a stable Hopf's limit cycle exists. By measuring the appearance and size of the Hopf's limit cycle, the electron cooling force can be deduced.

  11. Reflection of electromagnetic radiation from plasma with an anisotropic electron velocity distribution

    SciTech Connect

    Vagin, K. Yu. Uryupin, S. A.

    2013-08-15

    The reflection of a test electromagnetic pulse from the plasma formed as a result of tunnel ionization of atoms in the field of a circularly polarized high-power radiation pulse is analyzed using the kinetic approach to describe electron motion. It is shown that the reflected pulse is significantly amplified due to the development of Weibel instability. The amplification efficiency is determined by the maximum value of the instability growth rate, which depends on the degree of anisotropy of the photoelectron distribution function.

  12. Electromagnetic ion cyclotron mode (ELF) waves generated by auroral electron precipitation

    NASA Technical Reports Server (NTRS)

    Temerin, M.; Lysak, R. L.

    1984-01-01

    Narrow-banded ELF waves with frequencies between the local hydrogen and the singly-charged helium gyrofrequencies have been seen in the S3-3 satellite electric field wave data at altitudes between 800 and 8000 km. The waves are generated in or just below the auroral acceleration region by the accelerated electron beam and propagate in the Alfven-ion cyclotron branch of the cold electromagnetic dispersion relation as modified by the presence of a two ion H(+)-He(+) plasma.

  13. Femtosecond cooling of hot electrons in CdSe quantum-well platelets.

    PubMed

    Sippel, Philipp; Albrecht, Wiebke; van der Bok, Johanna C; Van Dijk-Moes, Relinde J A; Hannappel, Thomas; Eichberger, Rainer; Vanmaekelbergh, Daniel

    2015-04-01

    Semiconductor quantum wells are ubiquitous in high-performance optoelectronic devices such as solar cells and lasers. Understanding and controlling of the (hot) carrier dynamics is essential to optimize their performance. Here, we study hot electron cooling in colloidal CdSe quantum-well nanoplatelets using ultrafast two-photon photoemission spectroscopy at low excitation intensities, resulting typically in 1-5 hot electrons per platelet. We observe initial electron cooling in the femtosecond time domain that slows down with decreasing electron energy and is finished within 2 ps. The cooling is considerably faster at cryogenic temperatures than at room temperature, and at least for the systems that we studied, independent of the thickness of the platelets (here 3-5 CdSe units) and the presence of a CdS shell. The cooling rates that we observe are orders of magnitude faster than reported for similar CdSe platelets under strong excitation. Our results are understood by a classic cooling mechanism with emission of longitudinal optical phonons without a significant influence of the surface. PMID:25764379

  14. A comparative study of electron cooling rates in the Venus ionosphere during magnetized and unmagnetized conditions

    NASA Astrophysics Data System (ADS)

    Mahajan, K. K.; Upadhyay, H. O.; Ghosh, Suchita

    1996-04-01

    When the solar wind dynamic pressure (Psw) is high, the ``top'' of the Venus ionosphere (defined by the altitude where the steep density gradient begins) moves down to altitudes between 200 and 300 km. Thick ionopauses are formed in the region between 200 and 400 km and here the electron density decreases with a scale height of about 20 km. Further, these regions get permeated by strong horizontal magnetic fields. However, during conditions of low Psw, the ``top'' of the ionosphere moves to higher altitudes and the region between 200 and 400 km is nearly free of magnetic fields. This region then forms a part of the ``main'' ionosphere, where electron density decreases with a scale height of about 200 km. In this paper, we study the electron cooling processes and their rates in the region between 200 and 400 km for these two conditions, namely, (1) when this region is fully magnetized and (2) when this region is unmagnetized. We use Langmuir probe measurements of electron density and electron temperature from the Pioneer Venus Orbiter for these studies. We find that the dominant electron cooling process in the ionopause region is due to electronic excitation of the ground state of O to the O(1D) level. In the main ionosphere, the major processes are cooling due to the fine structure of O, and electron ion Coulomb collisions. Further, the cooling rates are lower in the ionopause region than in the ionospheric region. Only if thermal conduction is assumed to be inhibited in the presence of a horizontal magnetic field, the magnetized orbits can then be used to estimate heating rates by equating these to cooling rates (i.e., local equilibrium). Under this assumption, we find that heating rates so estimated are far smaller than those used by several workers in the heat balance models. However, these rates are closer to model values which include inhibition of photoelectron transport in the presence of a horizontal magnetic field.

  15. The effect of downward electron heat flow and electron cooling processes in the high-latitude ionosphere

    NASA Astrophysics Data System (ADS)

    David, M.; Schunk, R. W.; Sojka, J. J.

    2011-10-01

    The electron energy balance in the ionosphere is affected by numerous local heating and cooling processes, as well as by transport processes. The thermal electrons gain energy from photoelectrons, auroral electrons, hot thermal ions, and a downward flow of heat from high altitudes. The thermal electrons lose energy in elastic collisions with ions and neutrals (N2, O2, O, He, H) and in inelastic collisions with neutrals, including rotational excitation of N2 and O2, vibrational excitation of N2 and O2, excitation of the fine structure levels of atomic oxygen, and electronic excitation of atomic oxygen, e.g., O(1S) and O(1D). The transport processes include thermal conduction and thermoelectric heat flow. Recently, new electron cooling rates have been calculated that are substantially different from those in current use, which are more than thirty years old. Therefore, model simulations were conducted that show the impact that these new cooling rates have on the electron temperatures and ion densities in the mid- and high-latitude ionosphere. It was found that, while several of the new cooling rates differ significantly from the old rates, collectively these differences largely cancel each other, with the result that the impact of the new rates on the ionospheric temperatures and densities is small. Also, a possible important source of heat for the thermal electrons in the polar cap is the downward flow of heat that results from the interaction of the escaping polar wind electrons with the relatively hot polar rain, squall, and drizzle. This electron heat source has typically been ignored in the past due to a lack of measurements, but recent work based on satellite measurements has made it possible to estimate values of the downward electron heat flow in the polar cap. Therefore, model simulations were also conducted to determine the effect of a downward electron heat flow on the high-latitude ionosphere. We found that in many cases the addition of a heat flow does have a large impact on the F-region temperatures and densities, sometimes increasing the total electron content (TEC) by 50% or more; topside densities may be increased by a factor of 5. The effects of the new cooling rates and downward heat flow were determined for a wide range of geophysical conditions.

  16. Terahertz electromagnetic wave generation and amplification by an electron beam in the elliptical plasma waveguides with dielectric rod

    SciTech Connect

    Rahmani, Z. Jazi, B.; Heidari-Semiromi, E.

    2014-09-15

    The propagation of electromagnetic waves in an elliptical plasma waveguide including strongly magnetized plasma column and a dielectric rod is investigated. The dispersion relation of guided hybrid electromagnetic waves is obtained. Excitation of the waves by a thin annular relativistic elliptical electron beam will be studied. The time growth rate of electromagnetic waves is obtained. The effects of relative permittivity constant of dielectric rod, radius of dielectric rod, accelerating voltage, and current density of the annular elliptical beam on the growth rate and the frequency spectra are numerically presented.

  17. Rotational Cooling of HD+ Molecular Ions by Superelastic Collisions with Electrons

    NASA Astrophysics Data System (ADS)

    Shafir, D.; Novotny, S.; Buhr, H.; Altevogt, S.; Faure, A.; Grieser, M.; Harvey, A. G.; Heber, O.; Hoffmann, J.; Kreckel, H.; Lammich, L.; Nevo, I.; Pedersen, H. B.; Rubinstein, H.; Schneider, I. F.; Schwalm, D.; Tennyson, J.; Wolf, A.; Zajfman, D.

    2009-06-01

    Merging an HD+ beam with velocity matched electrons in a heavy ion storage ring we observed rapid cooling of the rotational excitations of the HD+ ions by superelastic collisions (SEC) with the electrons. The cooling process is well described using theoretical SEC rate coefficients obtained by combining the molecular R-matrix approach with the adiabatic nuclei rotation approximation. We verify the ΔJ=-2 SEC rate coefficients, which are predicted to be dominant as opposed to the ΔJ=-1 rates and to amount to (1-2)×10-6cm3s-1 for initial angular momentum states with J≤7, to within 30%.

  18. Single-molecule electronics: Cooling individual vibrational modes by the tunneling current.

    PubMed

    Lykkebo, Jacob; Romano, Giuseppe; Gagliardi, Alessio; Pecchia, Alessandro; Solomon, Gemma C

    2016-03-21

    Electronic devices composed of single molecules constitute the ultimate limit in the continued downscaling of electronic components. A key challenge for single-molecule electronics is to control the temperature of these junctions. Controlling heating and cooling effects in individual vibrational modes can, in principle, be utilized to increase stability of single-molecule junctions under bias, to pump energy into particular vibrational modes to perform current-induced reactions, or to increase the resolution in inelastic electron tunneling spectroscopy by controlling the life-times of phonons in a molecule by suppressing absorption and external dissipation processes. Under bias the current and the molecule exchange energy, which typically results in heating of the molecule. However, the opposite process is also possible, where energy is extracted from the molecule by the tunneling current. Designing a molecular "heat sink" where a particular vibrational mode funnels heat out of the molecule and into the leads would be very desirable. It is even possible to imagine how the vibrational energy of the other vibrational modes could be funneled into the "cooling mode," given the right molecular design. Previous efforts to understand heating and cooling mechanisms in single molecule junctions have primarily been concerned with small models, where it is unclear which molecular systems they correspond to. In this paper, our focus is on suppressing heating and obtaining current-induced cooling in certain vibrational modes. Strategies for cooling vibrational modes in single-molecule junctions are presented, together with atomistic calculations based on those strategies. Cooling and reduced heating are observed for two different cooling schemes in calculations of atomistic single-molecule junctions. PMID:27004879

  19. Single-molecule electronics: Cooling individual vibrational modes by the tunneling current

    NASA Astrophysics Data System (ADS)

    Lykkebo, Jacob; Romano, Giuseppe; Gagliardi, Alessio; Pecchia, Alessandro; Solomon, Gemma C.

    2016-03-01

    Electronic devices composed of single molecules constitute the ultimate limit in the continued downscaling of electronic components. A key challenge for single-molecule electronics is to control the temperature of these junctions. Controlling heating and cooling effects in individual vibrational modes can, in principle, be utilized to increase stability of single-molecule junctions under bias, to pump energy into particular vibrational modes to perform current-induced reactions, or to increase the resolution in inelastic electron tunneling spectroscopy by controlling the life-times of phonons in a molecule by suppressing absorption and external dissipation processes. Under bias the current and the molecule exchange energy, which typically results in heating of the molecule. However, the opposite process is also possible, where energy is extracted from the molecule by the tunneling current. Designing a molecular "heat sink" where a particular vibrational mode funnels heat out of the molecule and into the leads would be very desirable. It is even possible to imagine how the vibrational energy of the other vibrational modes could be funneled into the "cooling mode," given the right molecular design. Previous efforts to understand heating and cooling mechanisms in single molecule junctions have primarily been concerned with small models, where it is unclear which molecular systems they correspond to. In this paper, our focus is on suppressing heating and obtaining current-induced cooling in certain vibrational modes. Strategies for cooling vibrational modes in single-molecule junctions are presented, together with atomistic calculations based on those strategies. Cooling and reduced heating are observed for two different cooling schemes in calculations of atomistic single-molecule junctions.

  20. Electromagnetic cascade in high-energy electron, positron, and photon interactions with intense laser pulses

    NASA Astrophysics Data System (ADS)

    Bulanov, S. S.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.

    2013-06-01

    The interaction of high-energy electrons, positrons, and photons with intense laser pulses is studied in head-on collision geometry. It is shown that electrons and/or positrons undergo a cascade-type process involving multiple emissions of photons. These photons can consequently convert into electron-positron pairs. As a result charged particles quickly lose their energy developing an exponentially decaying energy distribution, which suppresses the emission of high-energy photons, thus reducing the number of electron-positron pairs being generated. Therefore, this type of interaction suppresses the development of the electromagnetic avalanche-type discharge, i.e., the exponential growth of the number of electrons, positrons, and photons does not occur in the course of interaction. The suppression will occur when three-dimensional effects can be neglected in the transverse particle orbits, i.e., for sufficiently broad laser pulses with intensities that are not too extreme. The final distributions of electrons, positrons, and photons are calculated for the case of a high-energy e-beam interacting with a counterstreaming, short intense laser pulse. The energy loss of the e-beam, which requires a self-consistent quantum description, plays an important role in this process, as well as provides a clear experimental observable for the transition from the classical to quantum regime of interaction.

  1. Nonlinear evolution of the electromagnetic electron-cyclotron instability in bi-Kappa distributed plasma

    SciTech Connect

    Eliasson, B.; Lazar, M.

    2015-06-15

    This paper presents a numerical study of the linear and nonlinear evolution of the electromagnetic electron-cyclotron (EMEC) instability in a bi-Kappa distributed plasma. Distributions with high energy tails described by the Kappa power-laws are often observed in collision-less plasmas (e.g., solar wind and accelerators), where wave-particle interactions control the plasma thermodynamics and keep the particle distributions out of Maxwellian equilibrium. Under certain conditions, the anisotropic bi-Kappa distribution gives rise to plasma instabilities creating low-frequency EMEC waves in the whistler branch. The instability saturates nonlinearly by reducing the temperature anisotropy until marginal stability is reached. Numerical simulations of the Vlasov-Maxwell system of equations show excellent agreement with the growth-rate and real frequency of the unstable modes predicted by linear theory. The wave-amplitude of the EMEC waves at nonlinear saturation is consistent with magnetic trapping of the electrons.

  2. Fokker-Planck electron diffusion caused by an obliquely propagating electromagnetic wave packet of narrow bandwidth

    NASA Technical Reports Server (NTRS)

    Hizanidis, Kyriakos

    1989-01-01

    The relativistic motion of electrons in an intense electromagnetic wave packet propagating obliquely to a uniform magnetic field is analytically studied on the basis of the Fokker-Planck-Kolmogorov (FPK) approach. The wavepacket consists of circularly polarized electron-cyclotron waves. The dynamical system in question is shown to be reducible to one with three degrees of freedom. Within the framework of the Hamiltonian analysis the nonlinear diffusion tensor is derived, and it is shown that this tensor can be separated into zeroth-, first-, and second-order parts with respect to the relative bandwidth. The zeroth-order part describes diffusive acceleration along lines of constant unperturbed Hamiltonian. The second-order part, which corresponds to the longest time scale, describes diffusion across those lines. A possible transport theory is outlined on the basis of this separation of the time scales.

  3. Effects of Electrons on the Electromagnetic Ion Cyclotron Instability: Solar Wind Implications

    NASA Astrophysics Data System (ADS)

    Shaaban, S. M.; Lazar, M.; Poedts, S.; Elhanbaly, A.

    2015-11-01

    In diffuse plasmas in space, particle-particle collisions are rare and inefficient, such that a plausible mechanism for constraining the temperature anisotropy of plasma particles may be provided by the resulting instabilities. The implication of the electromagnetic ion-cyclotron (EMIC) instability in the solar wind is still unclear because this instability is fast enough to relax the proton temperature anisotropy, but the 1 AU measurements do not conform to the instability thresholds predicted by the existing theories, which ignore the kinetic effects of electrons, assuming them to be isotropic. This paper presents a refined analysis of the EMIC instability in the presence of a temperature (T) anisotropy of electron (subscript “e”) population, i.e., {A}{{e}}={T}{{e},\\perp }/{T}{{e},\\parallel }\

  4. Development of a fast electromagnetic beam blanker for compressed sensing in scanning transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Béché, A.; Goris, B.; Freitag, B.; Verbeeck, J.

    2016-02-01

    The concept of compressed sensing was recently proposed to significantly reduce the electron dose in scanning transmission electron microscopy (STEM) while still maintaining the main features in the image. Here, an experimental setup based on an electromagnetic beam blanker placed in the condenser plane of a STEM is proposed. The beam blanker deflects the beam with a random pattern, while the scanning coils are moving the beam in the usual scan pattern. Experimental images at both the medium scale and high resolution are acquired and reconstructed based on a discrete cosine algorithm. The obtained results confirm that compressed sensing is highly attractive to limit beam damage in experimental STEM even though some remaining artifacts need to be resolved.

  5. Subnanosecond electron transport in a gas in the presence of polarized electromagnetic waves

    SciTech Connect

    Dey, Indranuj; Mathew, Jose V.; Bhattacharjee, Sudeep; Jain, Sachin

    2008-04-15

    An ensemble of free electrons in a classical Boltzmann gas under equilibrium condition follow a square law for the number of collisions suffered during random walk, in the elastic limit [N{proportional_to}({lambda}/{lambda}){sup 2}]. This study reveals for the first time that in the same limit the dependence is considerably modified in the presence of linearly polarized electromagnetic waves. The phenomenon happens at time scales shorter ({approx}10{sup -10} s) than the characteristic discharge initiation time and the wave period. Considering the actual dependence of collision cross-sections on electron energy, a new relation is obtained, which tends to the classical result for the zero field case. The random walk parameter <{chi}{sup 2}> characterizes a true versus constrained random process. The implications of the new relation describing the phenomena are discussed in the light of applications.

  6. Electronics cooling of Phenix multiplicity and vertex detector

    SciTech Connect

    Chen, Z.; Gregory, W.S.

    1996-08-01

    The Multiplicity and Vertex Detector (MVD) uses silicon strip sensors arranged in two concentric barrels around the beam pipe of the PHENIX detector that will be installed at Brookhaven National Laboratory. Each silicon sensor is connected by a flexible kapton cable to its own front-end electronics printed circuit board that is a multi-chip module or MCM. The MCMs are the main heat source in the system. To maintain the MVD at optimized operational status, the maximum temperature of the multi-chip modules must be below 40 C. Using COSMOS/M HSTAR for the Heat Transfer analysis, a finite element model of a typical MCM plate was created to simulate a 9m/s airflow and 9m/s mixed flow composed of 50% helium and 50% air respectively, with convective heat transfer on both sides of the plate. The results using a mixed flow of helium and air show that the average maximum temperature reached by the MCMs is 37.5 C. The maximum temperature which is represented by the hot spots on the MCM is 39.43 C for the helium and air mixture which meets the design temperature requirement 40 C. To maintain the Multiplicity and Vertex Detector at optimized operational status, the configuration of the plenum chamber, the power dissipated by the silicon chips, the fluid flow velocity and comparison on the MCM design parameters will be discussed.

  7. Attosecond Electro-Magnetic Forces Acting on Metal Nanospheres Induced By Relativistic Electrons

    NASA Astrophysics Data System (ADS)

    Lagos, M. J.; Batson, P. E.; Reyes-Coronado, A.; Echenique, P. M.; Aizpurua, J.

    2014-03-01

    Swift electron scattering near nanoscale materials provides information about light-matter behavior, including induced forces. We calculate time-dependent electromagnetic forces acting on 1-1.5 nm metal nanospheres induced by passing swift electrons, finding both impulse-like and oscillatory response forces. Initially, impulse-like forces are generated by a competition between attractive electric forces and repulsive magnetic forces, lasting a few attoseconds (5-10 as). Oscillatory, plasmonic response forces take place later in time, last a few femtoseconds (1- 5 fs), and apparently rely on photon emission by decay of the electron-induced surface plasmons. A comparison of the strength of these two forces suggests that the impulse-like behavior dominates the process, and can transfer significant linear momentum to the sphere. Our results advance understanding of the physics behind the observation of both attractive and repulsive behavior of gold nano-particles induced by electron beams in aberration-corrected electron microscopy. Work supported under DOE, Award # DE-SC0005132, Basque Gov. project ETORTEK inano, Spanish Ministerio de Ciencia e Innovacion, No. FIS2010-19609-C02-01.

  8. NREL Helps Cool the Power Electronics in Electric Vehicles (Fact Sheet)

    SciTech Connect

    Not Available

    2011-07-01

    Researchers at the National Renewable Energy Laboratory (NREL) are developing and demonstrating innovative heat-transfer technologies for cooling power electronics devices in hybrid and electric vehicles. In collaboration with 3M and Wolverine Tube, Inc., NREL is using surface enhancements to dissipate heat more effectively, permitting a reduction in the size of power electronic systems and potentially reducing the overall costs of electric vehicles.

  9. Observation of dynamics of impurity photoconductivity in n-GaAs caused by electron cooling

    SciTech Connect

    Aleshkin, V. Ya. Morozov, S. V.; Rumyantsev, V. V.; Tuzov, I. V.

    2015-01-15

    Experimental investigation of the time dependence of impurity photoconductivity in n-GaAs is carried out upon pulsed optical excitation. It is shown that a change in the photoconductivity is determined mainly by electron cooling in the first 20 ns after photoexcitation. A theoretical model for describing the dependences under observation is proposed.

  10. Radiation of de-excited electrons at large times in a strong electromagnetic plane wave

    SciTech Connect

    Kazinski, P.O.

    2013-12-15

    The late time asymptotics of the physical solutions to the Lorentz–Dirac equation in the electromagnetic external fields of simple configurations–the constant homogeneous field, the linearly polarized plane wave (in particular, the constant uniform crossed field), and the circularly polarized plane wave–are found. The solutions to the Landau–Lifshitz equation for the external electromagnetic fields admitting a two-parametric symmetry group, which include as a particular case the above mentioned field configurations, are obtained. Some general properties of the total radiation power of a charged particle are established. In particular, for a circularly polarized wave and constant uniform crossed fields, the total radiation power in the asymptotic regime is independent of the charge and the external field strength, when expressed in terms of the proper-time, and equals a half the rest energy of a charged particle divided by its proper-time. The spectral densities of the radiation power formed on the late time asymptotics are derived for a charged particle moving in the external electromagnetic fields of the simple configurations pointed above. This provides a simple method to verify experimentally that the charged particle has reached the asymptotic regime. -- Highlights: •Late time asymptotics of the solutions to the Lorentz–Dirac equation are studied. •General properties of the total radiation power of electrons are established. •The total radiation power equals a half the rest energy divided by the proper-time. •Spectral densities of radiation formed on the late time asymptotics are derived. •Possible experimental verification of the results is proposed.

  11. Comment on ''Chaotic electron trajectories in an electromagnetic wiggler free-electron laser with ion-channel guiding'' [Phys. Plasmas 17, 093103 (2010)

    SciTech Connect

    Nasr, N.; Hasanbeigi, A.

    2011-05-15

    The chaotic electron dynamics in a free-electron laser with electromagnetic-wave wiggler and ion-channel has been recently reported by A. Taghavi et al.[Phys. Plasmas 17, 093103 (2010)]. We comment on the authors use of a set of initial condition that is not correct based on the dispersion relation and steady-state orbits.

  12. High-Coherence Electron and Ion Bunches from Laser-Cooled Atoms

    NASA Astrophysics Data System (ADS)

    McCulloch, A. J.; Sheludko, D. V.; Putkunz, C. T.; Saliba, S. D.; Thompson, D. J.; Speirs, R. W.; Murphy, D.; Torrance, J.; Sparkes, B. M.; Scholten, R. E.

    2014-04-01

    Cold atom electron and ion sources produce electron bunches and ion beams by photoionisation of laser cooled atoms. They offer high coherence and the potential for high brightness, with applications including ultrafast electron diffractive imaging of dynamic processes at the nanoscale. Here we present our cold atom electron/ion source, with an electron temperature of less than 10 K and a transverse coherence length of 10 nm. We also discuss experiments investigating space-charge effects with ions and the production of ultra-fast electron bunches using a femto-second laser. In the latter experiment we show that it is possible to produce both cold and fast electron bunches with our source.

  13. Relativistically intense plane electromagnetic waves in electron-positron plasmas: Nonlinear self-modulation and harmonics generation regimes

    SciTech Connect

    Shiryaev, O. B.

    2006-11-15

    A fully nonlinear one-dimensional problem describing the interactions of relativistically intense plane electromagnetic waves and cold locally non-neutral electron-positron plasmas is derived from Maxwell and fluid dynamics equations. Numerical and asymptotic solutions to this problem for phase velocities close to the speed of light are presented. Depending on the magnitude of the plasma longitudinal electric-field potential, the system considered is found to support two distinct regimes of plane electromagnetic wave propagation: a nonlinear self-modulation one with the coupling of a fast transversely polarized electromagnetic field to a slow longitudinal plasma field, and a harmonics generation one with both of these fields oscillating with comparable frequencies. In the former case, a splitting of the electromagnetic field spectrum into a series of closely located bands occurs, whereas in the latter one the propagating field spectrum is a set of radiation harmonics.

  14. Hybridized Electromagnetic-Triboelectric Nanogenerator for a Self-Powered Electronic Watch.

    PubMed

    Quan, Ting; Wang, Xue; Wang, Zhong Lin; Yang, Ya

    2015-12-22

    We report a hybridized nanogenerator including a triboelectric nanogenerator (TENG) and six electromagnetic generators (EMGs) that can effectively scavenge biomechanical energy for sustainably powering an electronic watch. Triggered by the natural motions of the wearer's wrist, a magnetic ball at the center in an acrylic box with coils on each side will collide with the walls, resulting in outputs from both the EMGs and the TENG. By using the hybridized nanogenerator to harvest the biomechanical energy, the electronic watch can be continuously powered under different motion types of the wearer's wrist, where the best approach is to charge a 100 μF capacitor in 39 s to maintain the continuous operation of the watch for 456 s. To increase the working time of the watch further, a homemade Li-ion battery has been utilized as the energy storage unit for realizing the continuous working of the watch for about 218 min by using the hybridized nanogenerator to charge the battery within 32 min. This work will provide the opportunities for developing a nanogenerator-based built-in power source for self-powered wearable electronics such as an electronic watch. PMID:26565597

  15. Electron kappa distribution, quasi-thermal noise, and spontaneously-emitted electromagnetic fluctuations

    NASA Astrophysics Data System (ADS)

    Yoon, P. H.

    2014-12-01

    Spacecraft measurements of charged particles in the solar wind near 1 A.U. show that their velocity distributions deviate from thermal Maxwellian model. Typically, the measured distributions feature energetic components with quasi scale-free power-law velocity dependence in the high velocity range. It is customary to model such a feature by means of the kappa distribution, but recently the kappa distribution is understood as implying that the space plasma is in non-extensive thermo-statistical state. Alternatively, the kappa distribution may imply that the space plasma is in turbulent quasi-equilibrium state. The non-extensive state and the turbulent-equilibrium may turn out to be nothing but two different ways of describing the same physical state, although the proof is not so straightforward. The solar wind near 1 A.U. also pervasively shows the presence of electrostatic fluctuations called the quasi-thermal noise. The present talk overviews the theory of solar wind electron kappa distribution, the associated quasi-thermal noise fluctuation, and the newly-discovered spontaneously-generated electromagnetic radiation, which can all be discussed within a single, unified framework of electromagnetic weak turbulence theory.

  16. Cryogenic systems for proof of the principle experiment of coherent electron cooling at RHIC

    SciTech Connect

    Huang, Yuenian; Belomestnykh, Sergey; Brutus, Jean Clifford; Lederle, Dewey; Orfin, Paul; Skaritka, John; Soria, Victor; Tallerico, Thomas; Than, Roberto

    2014-01-29

    The Coherent electron Cooling (CeC) Proof of Principle (PoP) experiment is proposed to be installed in the Relativistic Heavy Ion Collider (RHIC) to demonstrate proton and ion beam cooling with this new technique that may increase the beam luminosity in certain cases, by as much as tenfold. Within the scope of this project, a 112 MHz, 2MeV Superconducting Radio Frequency (SRF) electron gun and a 704 MHz 20MeV 5-cell SRF cavity will be installed at IP2 in the RHIC ring. The superconducting RF electron gun will be cooled in a liquid helium bath at 4.4 K. The 704 MHz 5-cell SRF cavity will be cooled in a super-fluid helium bath at 2.0 K. This paper discusses the cryogenic systems designed for both cavities. For the 112 MHz cavity cryogenic system, a condenser/boiler heat exchanger is used to isolate the cavity helium bath from pressure pulses and microphonics noise sources. For the 704 MHz 5-cell SRF cavity, a heat exchanger is also used to isolate the SRF cavity helium bath from noise sources in the sub-atmospheric pumping system operating at room temperature. Detailed designs, thermal analyses and discussions for both systems will be presented in this paper.

  17. Electromagnetic fields from pulsed electron beam experiments in space - Spacelab-2 results

    NASA Technical Reports Server (NTRS)

    Bush, R. I.; Reeves, G. D.; Banks, P. M.; Neubert, T.; Williamson, P. R.

    1987-01-01

    During the Spacelab-2 mission a small satellite carrying various plasma diagnostic instruments was released from the Shuttle to coorbit at distances up to 300 m. During a magnetic conjunction of the Shuttle and the satellite an electron beam modulated at 1.22 kHz was emitted from the Shuttle during a 7 min period. The spatial structure of the electromagnetic fields generated by the beam was observed from the satellite out to a distance of 153 m perpendicular to the beam. The magnetic field amplitude of the strongest harmonics were comparable to the amplitude of simultaneously observed whistlers, while the electric field amplitudes were estimated to 1-10 mV/m.

  18. Exact solution of the dispersion equation for electromagnetic waves in sheared relativistic electron beams

    NASA Astrophysics Data System (ADS)

    Cuperman, S.; Heristchi, D.

    1992-08-01

    The transcendental dispersion equation for electromagnetic waves propagating in the slow mode in sheared non-neutral relativistic cylindrical electron beams in strong applied magnetic fields is solved exactly. Thus, rather than truncated power series for the modified Bessel functions involved, use is made of modern algorithms able to compute such functions up to 18-digit accuracy. Consequently, new and significantly more important branches of the velocity shear instability are found. When the shear-factor and/or the geometrical parameter a/b (pipe-to-beam radius ratio) are increased, the unstable branches join, and the higher-frequency, larger-wavenumber modes are significantly enhanced. Since analytical solutions of the exact dispersion relation cannot be obtained, it is suggested that in all similar cases the methods proposed and demonstrated here should be used to carry out a rigorous stability analysis.

  19. ELECTROMAGNETIC SIMULATIONS OF DIELECTRIC WALL ACCELERATOR STRUCTURES FOR ELECTRON BEAM ACCELERATION

    SciTech Connect

    Nelson, S D; Poole, B R

    2005-05-05

    Dielectric Wall Accelerator (DWA) technology incorporates the energy storage mechanism, the switching mechanism, and the acceleration mechanism for electron beams. Electromagnetic simulations of DWA structures includes these effects and also details of the switch configuration and how that switch time affects the electric field pulse which accelerates the particle beam. DWA structures include both bi-linear and bi-spiral configurations with field gradients on the order of 20MV/m and the simulations include the effects of the beampipe, the beampipe walls, the DWA High Gradient Insulator (HGI) insulating stack, wakefield impedance calculations, and test particle trajectories with low emittance gain. Design trade-offs include the transmission line impedance (typically a few ohms), equilibration ring optimization, driving switch inductances, and layer-to-layer coupling effects and the associated affect on the acceleration pulse's peak value.

  20. A long electromagnetic wiggler for the paladin free-electron laser experiments

    SciTech Connect

    Deis, G.A.; Harvey, A.R.; Parkison, C.D.; Prosnitz, D.; Rego, J.; Scharlemann, E.T.; Halbach, K.

    1988-03-01

    The authors have designed, built, and tested a 25.6-m-long wiggler for a free-electron-laser (FEL) experiment. It is a DC iron-core electromagnetic wiggler that incorporates a number of important and unique facilities. Permanent magnets are used to suppress saturation in the iron and extend the linear operating range. Steering-free excitation allows real-time adjustment of the field taper without causing beam steering. Wiggle-plane focusing is produced by curved pole tips. The magnitude of random pole-to-pole field errors is minimized by a mechanical design concept that reduces tolerance stackup in critical locations. To date, the authors have tested 15 m of this wiggler, and their measurements have shown exceptionally low levels of random errors.

  1. A long electromagnetic wiggler for the paladin free-electron laser experiments

    SciTech Connect

    Deis, G.A.; Harvey, A.R.; Parkison, C.D.; Prosnitz, D.; Rego, J.; Scharlemann, E.T.; Halbach, K.

    1987-01-01

    We have designed, built, and tested a 25.6-m-long wiggler for a free-electron-laser (FEL) experiment. It is a DC iron-core electromagnetic wiggler that incorporates a number of important and unique features. Permanent magnets are used to suppress saturation in the iron and extend the linear operating range. Steering-free excitation allows real-time adjustment of the field taper without causing beam steering. Wiggle-plane focusing is produced by curved pole tips. The magnitude of random pole-to-pole field errors is minimized by a mechanical design concept that reduces tolerance stackup in critical locations. To date, we have tested 15 m of this wiggler, and our measurements have shown exceptionally low levels of random errors. 8 refs.

  2. Spectroscopy and dynamics of jet-cooled hydrazines and ammonia. II - Electron-impact dissociative ionization

    NASA Astrophysics Data System (ADS)

    Syage, Jack A.

    1992-11-01

    A crossed electron molecular beam apparatus is presently used to measure dissociative-ionization cross sections, fragment appearance potentials, and fragment kinetic energies of the electron-impact excitation of jet-cooled NH3, hydrazine, and monomethyl hydrazine (MMH) over the 10-270 eV energy range. The kinetic energies for hydrazine and MMH fragment ions at similar excitation energies are typically much lower than those for NH3, in keeping with statistical arguments based on the density of internal states. The role of electronic structure and geometry on dissociation is explored on the basis of a molecular orbital analysis.

  3. Integration of electronic system with electro-thermally cooled IR detector: thermal analysis

    NASA Astrophysics Data System (ADS)

    Raj, E.; Lisik, Z.; Ruta, L.; Guzowski, B.; Kalinowski, P.; Orman, Z.

    2016-01-01

    The paper presents thermal investigations of an idea of encapsulation in common, miniature package both preamplifier circuit and infrared photodetector cooled with the aid of four-stage thermoelectric module. Conducted numerical simulations show that the presence of electronics at printed circuit board with either ceramic or laminate substrate negligibly affects operation of thermoelectric cooler and hence, the operating conditions of the detector. Higher thermal loads are reported when placing wideband electronic system on the additional thermoelectric module. Even though, such solution reduces temperature difference between infrared sensor and the other part of electronics, additional cooler increases the amount of heat that must be dissipated from the package to the ambient.

  4. Nonlinear dispersion and transverse profile of intense electromagnetic waves, propagating through electron-positron-ion hot magnetoplasma

    SciTech Connect

    Javan, N. Sepehri Homami, S. H. H.

    2015-02-15

    Self-guided nonlinear propagation of intense circularly-polarized electromagnetic waves in a hot electron-positron-ion magnetoplasma is studied. Using a relativistic fluid model, a nonlinear equation is derived, which describes the interaction of the electromagnetic wave with the plasma in the quasi-neutral approximation. Transverse Eigen modes, the nonlinear dispersion relation and the group velocity are obtained. Results show that the transverse profile in the case of magnetized plasma with cylindrical symmetry has a radially damping oscillatory form. Effect of applying external magnetic fields, existence of the electron-positron pairs, changing the amplitude of the electromagnetic wave, and its polarization on the nonlinear dispersion relation and Eigen modes are studied.

  5. Interaction of a two-dimensional electromagnetic breather with an electron inhomogeneity in an array of carbon nanotubes

    SciTech Connect

    Zhukov, Alexander V. Bouffanais, Roland; Fedorov, E. G.; Belonenko, Mikhail B.

    2014-05-28

    Propagation of ultrashort laser pulses through various nano-objects has recently became an attractive topic for both theoretical and experimental studies due to its promising perspectives in a variety of problems of modern nanoelectronics. Here, we study the propagation of extremely short two-dimensional bipolar electromagnetic pulses in a heterogeneous array of semiconductor carbon nanotubes. Heterogeneity is defined as a region of enhanced electron density. The electromagnetic field in an array of nanotubes is described by Maxwell's equations, reduced to a multidimensional wave equation. Our numerical analysis shows the possibility of stable propagation of an electromagnetic pulse in a heterogeneous array of nanotubes. Furthermore, we establish that, depending on its speed of propagation, the pulse can pass through the area of increased electron concentration or be reflected therefrom.

  6. Observation of electron plasma waves inside large amplitude electromagnetic pulses in a temporally growing plasma

    SciTech Connect

    Pandey, Shail; Bhattacharjee, Sudeep; Sahu, Debaprasad

    2012-01-15

    Observation of electron plasma waves excited inside high power ({approx}10 kW) short pulse ({approx}20 {mu}s) electromagnetic (em) waves interacting with a gaseous medium (argon) in the pressure range 0.2-2.5 mTorr is reported. The waves have long wavelength ({approx}13 cm) and get damped at time scales slower ({approx}3 {mu}s) than the plasma period (0.1-0.3 {mu}s), the energy conveyed to the medium lead to intense ionization (ion density n{sub i} {approx} 10{sup 11} cm{sup -3} and electron temperature T{sub e} {approx} 6-8 eV) and rapid growth of the plasma ({approx}10{sup 5} s{sup -1}) beyond the waves. Time frequency analysis of the generated oscillations indicate the presence of two principal frequencies centered around 3.8 MHz and 13.0 MHz with a spread {Delta}f {approx} 4 MHz, representing primarily two population of electrons in the plasma wave. The experimental results are in reasonable agreement with a model that considers spatiotemporal forces of the em wave on the medium, space charges and diffusion.

  7. Proof-of-principle experiment for FEL-based coherent electron cooling

    SciTech Connect

    Litvinenko, V.N.; Belomestnykh, S.; Ben-Zvi, I.; Brutus, J.C.; Fedotov, A.; Hao, Y.; Kayran, D.; Mahler, G.; Marusic, A.; Meng, W.; McIntyre, G.; Minty, M.; Ptitsyn, V.; Pinayev, I.; Rao, T.; Roser, T.; Sheehy, B.; Tepikian, S.; Than, Y.; Trbojevic, D.; Tuozzolo, J.; Wang, G.; Yakimenko, V.; Poelker, M.; Hutton, A.; Kraft, G.; Rimmer, R.; Bruhwiler, D.L.; Abell, D.T.; Nieter, C.; Ranjbar, V.; Schwartz, B.T.; Vobly, P.; Kholopov, M.; Shevchenko, O.; Mcintosh, P.; Wheelhouse, A.

    2011-08-21

    Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using SRF linac. In this paper, we describe the setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC. We plan to complete the program in five years. During first two years we will build coherent electron cooler in IP2 of RHIC. In parallel we will develop complete package of computer simulation tools for the start-to-end simulation predicting exact performance of a CeC. The later activity will be the core of Tech X involvement into the project. We will use these tools to predict the performance of our CeC device. The experimental demonstration of the CeC will be undertaken in years three to five of the project. The goal of this experiment is to demonstrate the cooling of ion beam and to compare its measured performance with predictions made by us prior to the experiments.

  8. Effect of a novel nonlinearity, viz., electron temperature dependence of electron-ion recombination on electromagnetic wave. Plasma interaction: Nonlinear propagation in the E-layer

    NASA Astrophysics Data System (ADS)

    Sodha, Mahendra Singh; Mishra, Rashmi; Srivastava, Sweta

    2016-03-01

    In this paper, we consider the nonlinearity in the propagation of electromagnetic (e.m.) waves in a plasma caused by the electron temperature dependence of the coefficient of recombination of electrons with ions; specifically, the ionospheric E layer has been investigated. The enhancement in electron temperature by an intense electromagnetic wave causes reduction of the electron-ion recombination coefficient and thereby enhancement of electron density, the electron collision frequency also gets enhanced. The equations for number and energy balance of electrons and the wave equation have been used to predict the dependence of electron density/collision frequency and the nonlinear refractive index and absorption coefficient on αE02 (proportional to wave irradiance). The dependence of the propagation parameters on αE02 has been used to investigate the nonlinear electromagnetic wave propagation in the ionosphere. The study concludes that the electron temperature dependence of the recombination coefficient should be considered in all analyses of nonlinear plasma-e.m. wave interaction.

  9. An Electromagnetic Spectrum for Millennial Students: Teaching Light, Color, Energy, and Frequency Using the Electronic Devices of Our Time

    ERIC Educational Resources Information Center

    Murphy, Maureen Kendrick

    2010-01-01

    In this article, a comparison of student learning outcomes is made in sophomore-level physical science classes using a "traditional" pedagogical approach versus a "modern" approach. Specifically, when students were taught the electromagnetic spectrum using diagrams and examples that incorporate technological advances and electronic devices of our…

  10. An Electromagnetic Spectrum for Millennial Students: Teaching Light, Color, Energy, and Frequency Using the Electronic Devices of Our Time

    ERIC Educational Resources Information Center

    Murphy, Maureen Kendrick

    2010-01-01

    In this article, a comparison of student learning outcomes is made in sophomore-level physical science classes using a "traditional" pedagogical approach versus a "modern" approach. Specifically, when students were taught the electromagnetic spectrum using diagrams and examples that incorporate technological advances and electronic devices of our

  11. Towards the measurement of the electron EDM with laser cooled francium atoms

    NASA Astrophysics Data System (ADS)

    Kawamura, Hirokazu; Ando, S.; Aoki, T.; Arikawa, H.; Ezure, S.; Harada, K.; Hayamizu, T.; Inoue, T.; Ishikawa, T.; Itoh, M.; Kato, K.; Sakamoto, K.; Uchiyama, A.; Aoki, T.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Nataraj, H. S.; Sato, T.; Shimizu, Y.; Yoshida, H. P.; Wakasa, T.; Sakemi, Y.

    2014-09-01

    The electric dipole moment (EDM) of a particle is a probe into new physics beyond the standard model. The electron EDM might be observed with an enhancement in heavier paramagnetic atoms. Francium (Fr), whose electron structure is useful for laser-cooling and trapping, has a large enhancement factor. Fr produced at high temperature via a fusion reaction will be laser-cooled and trapped in an optical lattice where the EDM is measured. The magneto-optical trapping of Fr is required in advance of the lattice trapping. The technique observing a small number of atoms makes it easy to search for the resonant frequency of Fr. The improvement of the beam purity should lead to a more efficient trap. The techniques towards Fr trapping and EDM measurement have been developed. The electric dipole moment (EDM) of a particle is a probe into new physics beyond the standard model. The electron EDM might be observed with an enhancement in heavier paramagnetic atoms. Francium (Fr), whose electron structure is useful for laser-cooling and trapping, has a large enhancement factor. Fr produced at high temperature via a fusion reaction will be laser-cooled and trapped in an optical lattice where the EDM is measured. The magneto-optical trapping of Fr is required in advance of the lattice trapping. The technique observing a small number of atoms makes it easy to search for the resonant frequency of Fr. The improvement of the beam purity should lead to a more efficient trap. The techniques towards Fr trapping and EDM measurement have been developed. Supported by MEXT/JSPS KAKENHI Grants (21104005, 25610112 and 26220705) and Tohoku University's Focused Research Project.

  12. Status of Proof-of-principle Experiment for Coherent Electron Cooling

    SciTech Connect

    Pinayev, I; Ben-Zvi, I; Bengtsson, J; Elizarov, A; Fedotov, A V; Gassner, D M; Hao, Y; Kayran, D; Litvinenko, V; Mahler, G J; Meng, W; Roser, T; Sheehy, B; Than, R; Tuozzolo, J E; Wang, G; Webb, S D; Yakimenko, V; Bell, G I; Bruhwiler, D L; Ranjbar, V H; Schwartz, B T; Hutton, A; Krafft, G A; Poelker, M; Rimmer, R A; Kholopov, M A

    2012-07-01

    Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o'clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.

  13. Theoretical study of electromagnetic electron cyclotron waves in the presence of AC field in Uranian magnetosphere

    NASA Astrophysics Data System (ADS)

    Pandey, R. S.; Kaur, Rajbir

    2015-10-01

    Electromagnetic electron cyclotron (EMEC) waves with temperature anisotropy in the magnetosphere of Uranus have been studied in present work. EMEC waves are investigated using method of characteristic solution by kinetic approach, in presence of AC field. In 1986, Voyager 2 encounter with Uranus revealed that magnetosphere of Uranus exhibit non-Maxwellian high-energy tail distribution. So, the dispersion relation, real frequency and growth rate are evaluated using Lorentzian Kappa distribution function. Effect of temperature anisotropy, AC frequency and number density of particles is found. The study is also extended to oblique propagation of EMEC waves in presence and absence of AC field. Through comprehensive mathematical analysis it is found that when EMEC wave propagates parallel to intrinsic magnetic field of Uranus, its growth is more enhanced than in case of oblique propagation. Results are also discussed in context to magnetosphere of Earth and also gives theoretical explanation to existence of high energetic particles observed by Voyager 2 in the magnetosphere of Uranus. The results can present a further insight into the nature of electron-cyclotron instability condition for the whistler mode waves in the outer radiation belts of Uranus or other space plasmas.

  14. Cool and Quiet: Partnering to Enhance the Aerodynamic and Acoustic Performance of Installed Electronics Cooling Fans: A White Paper

    NASA Technical Reports Server (NTRS)

    Koch, L. Danielle; VanZante, Dale E.

    2006-01-01

    Breathtaking images of distant planets. Spacewalks to repair a telescope in orbit. Footprints on the moon. The awesome is made possible by the mundane. Every achievement in space exploration has relied on solid, methodical advances in engineering. Space exploration fuels economic development like no other endeavor can. But which advances will make their way into our homes and businesses? And how long will it take? Answers to these questions are dependent upon industrial involvement in government sponsored research initiatives, market demands, and timing. Recognizing an opportunity is half the battle. This proposal describes the framework for a collaborative research program aimed at improving the aerodynamic and acoustic performance of electronics cooling fans. At its best, the program would involve NASA and academic researchers, as well as corporate researchers representing the Information Technology (IT) and fan manufacturing industries. The momentum of space exploration, the expertise resultant from the nation's substantial investment in turbofan noise reduction research, and the competitiveness of the IT industry are intended to be catalysts of innovation.

  15. Low Energy Electron Cooling and Accelerator Physics for the Heidelberg CSR

    SciTech Connect

    Fadil, H.; Grieser, M.; Hahn, R. von; Orlov, D.; Schwalm, D.; Wolf, A.; Zajfman, D.

    2006-03-20

    The Cryogenic Storage Ring (CSR) is currently under construction at MPI-K in Heidelberg. The CSR is an electrostatic ring with a total circumference of about 34 m, straight section length of 2.5 m and will store ions in the 20 {approx} 300 keV energy range (E/Q). The cryogenic system in the CSR is expected to cool the inner vacuum chamber down to 2 K. The CSR will be equipped with an electron cooler which has also to serve as an electron target for high resolution recombination experiments. In this paper we present the results of numerical investigations of the CSR lattice with finite element calculations of the deflection and focusing elements of the ring. We also present a layout of the CSR electron cooler which will have to operate in low energy mode to cool 20 keV protons in the CSR, as well as numerical estimations of the cooling times to be expected with this device.

  16. Heat-flux control and solid-state cooling by regulating chemical potential of photons in near-field electromagnetic heat transfer

    NASA Astrophysics Data System (ADS)

    Chen, Kaifeng; Santhanam, Parthiban; Sandhu, Sunil; Zhu, Linxiao; Fan, Shanhui

    2015-04-01

    We consider near-field heat transfer with nonzero chemical potential for photons, as can occur between two semiconductor bodies, held at different temperatures with at least one of the bodies under external bias. We show that the dependence of radiative heat flux on chemical potential enables electronic control of both the direction and magnitude of near-field heat transfer between the two bodies. Moreover such a configuration can operate as a solid-state cooling device whose efficiency can approach the Carnot limit in the ideal case. Significant cooling can also be achieved in the presence of inherent nonidealities including Auger recombination and parasitic phonon-polariton heat transfer.

  17. Pitch-angle diffusion of electrons through growing and propagating along a magnetic field electromagnetic wave in Earth's radiation belts

    NASA Astrophysics Data System (ADS)

    Choi, C.-R.; Woo, M.-H.; Dokgo, K.; Choi, E.-J.; Min, K.-W.; Hwang, J.; Park, Y.-D.; Lee, D.-Y.

    2015-06-01

    The diffusion of electrons via a linearly polarized, growing electromagnetic (EM) wave propagating along a uniform magnetic field is investigated. The diffusion of electrons that interact with the growing EM wave is investigated through the autocorrelation function of the parallel electron acceleration in several tens of electron gyration timescales, which is a relatively short time compared with the bounce time of electrons between two mirror points in Earth's radiation belts. Furthermore, the pitch-angle diffusion coefficient is derived for the resonant and non-resonant electrons, and the effect of the wave growth on the electron diffusion is discussed. The results can be applied to other problems related to local acceleration or the heating of electrons in space plasmas, such as in the radiation belts.

  18. Pitch-angle diffusion of electrons through growing and propagating along a magnetic field electromagnetic wave in Earth's radiation belts

    SciTech Connect

    Choi, C.-R. Dokgo, K.; Min, K.-W.; Woo, M.-H.; Choi, E.-J.; Hwang, J.; Park, Y.-D.; Lee, D.-Y.

    2015-06-15

    The diffusion of electrons via a linearly polarized, growing electromagnetic (EM) wave propagating along a uniform magnetic field is investigated. The diffusion of electrons that interact with the growing EM wave is investigated through the autocorrelation function of the parallel electron acceleration in several tens of electron gyration timescales, which is a relatively short time compared with the bounce time of electrons between two mirror points in Earth's radiation belts. Furthermore, the pitch-angle diffusion coefficient is derived for the resonant and non-resonant electrons, and the effect of the wave growth on the electron diffusion is discussed. The results can be applied to other problems related to local acceleration or the heating of electrons in space plasmas, such as in the radiation belts.

  19. Production and ion-ion cooling of highly charged ions in electron string ion source.

    PubMed

    Donets, D E; Donets, E D; Donets, E E; Salnikov, V V; Shutov, V B; Syresin, E M

    2009-06-01

    The scheme of an internal injection of Au atoms into the working space of the "Krion-2" electron string ion source (ESIS) was applied and tested. In this scheme Au atoms are evaporated from the thin tungsten wire surface in vicinity of the source electron string. Ion beams with charge states up to Au51+ were produced. Ion-ion cooling with use of C and O coolant ions was studied. It allowed increasing of the Au51+ ion yield by a factor of 2. Ions of Kr up to charge state 28+ were also produced in the source. Electron strings were first formed with injection electron energy up to 6 keV. Methods to increase the ESIS ion output are discussed. PMID:19566200

  20. Electromagnetic metamaterial-inspired band gap and perfect transmission in semiconductor and graphene-based electronic and photonic structures

    NASA Astrophysics Data System (ADS)

    Mahdy, M. R. C.; Al Sayem, Ayed; Shahriar, Arif; Shawon, Jubayer; Al-Quaderi, Golam Dastegir; Jahangir, Ifat; Matin, M. A.

    2016-04-01

    In this article, at first we propose a unified and compact classification of single negative electromagnetic metamaterial-based perfect transmission unit cells. The classes are named as: type-A, -B and -C unit cells. Then based on the classification, we have extended these ideas in semiconductor and graphene regimes. For type-A: Based on the idea of electromagnetic Spatial Average Single Negative bandgap, novel bandgap structures have been proposed for electron transmission in semiconductor heterostructures. For type-B: with dielectric-graphene-dielectric structure, almost all angle transparency is achieved for both polarizations of electromagnetic wave in the terahertz frequency range instead of the conventional transparency in the microwave frequency range. Finally the application of the gated dielectric-graphene-dielectric has been demonstrated for the modulation and switching purpose.

  1. Propagation and Generation of Electromagnetic Waves at Proton Gyrofrequencies in a Relativistic Electron-Positron Plasma. II. Excitation of Electromagnetic Waves

    NASA Astrophysics Data System (ADS)

    Zheleznyakov, V. V.; Bespalov, P. A.

    2016-05-01

    In part I of this work [1], we study the dispersion characteristics of low-frequency waves in a relativistic electron-positron plasma. In part II, we examine the electromagnetic wave instability in this plasma caused by an admixture of nonrelativistic protons with energy comparable with the energy of relativistic low-mass particles. The instability occurs in the frequency band between the fundamental harmonic of proton gyrofrequency and the fundamental harmonic of relativistic electron gyrofrequency. The results can be used for the interpretation of known observations of the pulsar emissions obtained with a high time and frequency resolution. The considered instability can probably be the initial stage of the microwave radio emission nanoshots typical of the pulsar in the Crab Nebula.

  2. Laser Cooled Francium Factory for the Electron Electric Dipole Moment Search

    NASA Astrophysics Data System (ADS)

    Hayamizu, Tomohiro; Arikawa, Hiroshi; Ezure, Saki; Harada, Ken-ichi; Inoue, Takeshi; Ishikawa, Taisuke; Itoh, Masatoshi; Kato, Tomohiro; Kawamura, Hirokazu; Sato, Tomoya; Ando, Shun; Aoki, Takahiro; Kato, Ko; Uchiyama, Aiko; Aoki, Takatoshi; Furukawa, Takeshi; Hatakeyama, Atsushi; Hatanaka, Kichiji; Imai, Kenichi; Murakami, Tetsuya; Nataraj, Huliyar; Shimizu, Yasuhiro; Wakasa, Tomotsugu; Yoshida, Hidetomo; Sakemi, Yasuhiro

    A permanent electric dipole moment (EDM) of an elementary particle is a candidate observable exhibiting CP violation beyond the standard model. In the present study, we plan to search for the electron EDM in francium (Fr), which is the heaviest alkali atom, captured in a far-off resonance optical trap. Since the number of Fr atoms is essential to high precision measurements, we have developed a cold Fr source called "Laser cooled Fr factory" in order to trap the radioactive Fr produced through a nuclear fusion reaction. The Fr produced was released as an ion from a gold production target in a Fr ion source, transported as an ion beam, and converted from ion to atom in a neutralizer. The neutralized Fr atom will be trapped in a magneto-optical trap(MOT) and then be transferred to an optical dipole trap. The rate of Fr atoms so far achieved was 1 × 106 ions/sec from the ion source and 1 atom/sec of the neutralized Fr atom from the neutralizer. In order to optimize performance of the Fr beam line, Rb atoms were trapped in the MOT. In addition to the beam-line experiment, in an off-line MOT system, polarization gradient cooling was applied to the trapped Rb atoms to cool them down to temperatures lower than the Rb Doppler-cooling limit. In this paper, we describe the present status of this experimental apparatus.

  3. Standing electromagnetic solitons in hot ultra-relativistic electron-positron plasmas

    SciTech Connect

    Heidari, E.; Aslaninejad, M.; Eshraghi, H.; Rajaee, L.

    2014-03-15

    Using a one-dimensional self-consistent fluid model, we investigate standing relativistic bright solitons in hot electron-positron plasmas. The positron dynamics is taken into account. A set of nonlinear coupled differential equations describing the evolution of electromagnetic waves in fully relativistic two-fluid plasma is derived analytically and solved numerically. As a necessary condition for the existence of standing solitons the system should be relativistic. For the case of ultra-relativistic plasma, we investigate non-drifting bright solitary waves. Detailed discussions of the acceptable solutions are presented. New single hump non-trivial symmetric solutions for the scalar potential were found, and single and multi-nodal symmetric and anti-symmetric solutions for the vector potential are presented. It is shown that for a fixed value of the fluid velocity excited modes with more zeros in the profile of the vector potential show a higher magnitude for the scalar potential. An increase in the plasma fluid velocity also increases the magnitude of the scalar potential. Furthermore, the Hamiltonian and the first integral of the system are given.

  4. Oblique electromagnetic electron cyclotron waves for Kappa distribution with AC field in planetary magnetospheres

    NASA Astrophysics Data System (ADS)

    Pandey, R. S.; Kaur, Rajbir

    2015-08-01

    The dispersion relation for obliquely propagating relativistic electromagnetic electron cyclotron (EMEC) waves in collision-less magnetoplasma is obtained. Investigations for EMEC waves in magnetosphere of Jupiter, Saturn and Uranus have been done, in presence of perpendicular AC electric field for Kappa distribution function. The relativistic temporal growth rate is calculated using method of characteristic solution. Using the data provided by spacecrafts like Cassini, Voyager 1 and 2, while exploring the magnetosphere of Jupiter, Saturn and Uranus, is used to plot graphs showing growth rate being effected by various parameters. Comprehensive parametric analysis have been done at different radial distances of the planets. It is concluded that beside huge difference in magnetospheric configuration, temperature anisotropy remains the main source of energy in case of Jupiter and Uranus. While studying EMEC waves in magnetosphere of Saturn, it is inferred that growth rate attains maximum magnitude when angle of propagation increases. Also, the results and its interpretations explain how the growth of EMEC wave modifies in different magnetospheric conditions.

  5. Floating Refrigerant Loop Based on R-134a Refrigerant Cooling of High-Heat Flux Electronics

    SciTech Connect

    Lowe, K.T.

    2005-10-07

    The Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) have been developing technologies to address the thermal issues associated with hybrid vehicles. Removal of the heat generated from electrical losses in traction motors and their associated power electronics is essential for the reliable operation of motors and power electronics. As part of a larger thermal control project, which includes shrinking inverter size and direct cooling of electronics, ORNL has developed U.S. Patent No. 6,772,603 B2, ''Methods and Apparatus for Thermal Management of Vehicle Systems and Components'' [1], and patent pending, ''Floating Loop System for Cooling Integrated Motors and Inverters Using Hot Liquid Refrigerant'' [2]. The floating-loop system provides a large coefficient of performance (COP) for hybrid-drive component cooling. This loop (based on R-134a) is integrated with a vehicle's existing air-conditioning (AC) condenser, which dissipates waste heat to the ambient air. Because the temperature requirements for cooling of power electronics and electric machines are not as low as that required for passenger compartment air, this adjoining loop can operate on the high-pressure side of the existing AC system. This arrangement also allows the floating loop to run without the need for the compressor and only needs a small pump to move the liquid refrigerant. For the design to be viable, the loop must not adversely affect the existing system. The loop should also provide a high COP, a flat-temperature profile, and low-pressure drop. To date, the floating-loop test prototype has successfully removed 2 kW of heat load in a 9 kW automobile passenger AC system with and without the automotive AC system running. The COP for the tested floating-loop system ranges from 40-45, as compared to a typical AC system COP of about 2-4. The estimated required waste-heat load for future hybrid applications is 5.5 kW and the existing system could be easily scaleable for this larger load.

  6. Effects of electromagnetic wiggler and ion channel guiding on equilibrium orbits and waves propagation in a free electron laser

    NASA Astrophysics Data System (ADS)

    Amri, Hassan Ehsani; Mohsenpour, Taghi

    2016-02-01

    In this paper, an analysis of equilibrium orbits for electrons by a simultaneous solution of the equation of motion and the dispersion relation for electromagnetic wave wiggler in a free-electron laser (FEL) with ion-channel guiding has been presented. A fluid model has been used to investigate interactions among all possible waves. The dispersion relation has been derived for electrostatic and electromagnetic waves with all relativistic effects included. This dispersion relation has been solved numerically. For group I and II orbits, when the transverse velocity is small, only the FEL instability is found. In group I and II orbits with relatively large transverse velocity, new couplings between other modes are found.

  7. Improvement of the technique of identification of electrons and positrons with use of electromagnetic calorimeter of the CLAS detector

    SciTech Connect

    Gevorgyan, N. E.; Dashyan, N. B.; Paremuzyan, R. G.; Stepanyan, S. G.

    2010-01-01

    We study the dependence of the sensitivity of response of the electromagnetic calorimeter of CLAS plant on the momenta of electrons and positrons. We made calculation of this dependence and elaborated a method for its employment in identification of e- and e+. We have shown that the new method of selection of e- and e+ improves the quality of identification by about 10%. We used the experimental data obtained with the plant CLAS of linear accelerator at Jefferson laboratory (USA).

  8. The influence of longitudinal space charge fields on the modulation process of coherent electron cooling

    SciTech Connect

    Wang, G.; Blaskiewicz, M.; Litvinenko, V. N.

    2014-05-21

    Initial modulation in Coherent electron cooling (CeC) scheme relies on ion charge screening by electrons. In a CeC system with bunched electron beam, the long-range longitudinal space charge force is inevitably induced. For a relatively dense electron beam, it can be comparable or even greater than the attractive force from the ion. Hence, space-charge field influence to the modulation process could be important. If the longitudinal Debye length is much smaller than the electron bunch length, the modulation induced by the ion happens locally. In this case, the long-range longitudinal space charge field can be approximated as a uniform electric field across the region. In this paper we developed an analytical model to study the dynamics of ion shielding in the presence of a uniform electric field. We are solving the coupled Vlasov-Poisson equation system for infinite anisotropic electron plasma and estimate the influences of the longitudinal space charge field to the modulation process. We present numerical estimates for a case of the proof of CeC principle experiment at RHIC.

  9. Electron-cooled accumulation of 4 × 109 positrons for production and storage of antihydrogen atoms

    NASA Astrophysics Data System (ADS)

    Fitzakerley, D. W.; George, M. C.; Hessels, E. A.; Skinner, T. D. G.; Storry, C. H.; Weel, M.; Gabrielse, G.; Hamley, C. D.; Jones, N.; Marable, K.; Tardiff, E.; Grzonka, D.; Oelert, W.; Zielinski, M.; ATRAP Collaboration

    2016-03-01

    Four billion positrons (e+) are accumulated in a Penning-Ioffe trap apparatus at 1.2 K and <6 × 10-17 Torr. This is the largest number of positrons ever held in a Penning trap. The e+ are cooled by collisions with trapped electrons (e-) in this first demonstration of using e- for efficient loading of e+ into a Penning trap. The combined low temperature and vacuum pressure provide an environment suitable for antihydrogen (\\bar{{{H}}}) production, and long antimatter storage times, sufficient for high-precision tests of antimatter gravity and of CPT.

  10. Ion acoustic solitons and supersolitons in a magnetized plasma with nonthermal hot electrons and Boltzmann cool electrons

    SciTech Connect

    Rufai, O. R. Bharuthram, R.; Singh, S. V. Lakhina, G. S.

    2014-08-15

    Arbitrary amplitude, ion acoustic solitons, and supersolitons are studied in a magnetized plasma with two distinct groups of electrons at different temperatures. The plasma consists of a cold ion fluid, cool Boltzmann electrons, and nonthermal energetic hot electrons. Using the Sagdeev pseudo-potential technique, the effect of nonthermal hot electrons on soliton structures with other plasma parameters is studied. Our numerical computation shows that negative potential ion-acoustic solitons and double layers can exist both in the subsonic and supersonic Mach number regimes, unlike the case of an unmagnetized plasma where they can only exist in the supersonic Mach number regime. For the first time, it is reported here that in addition to solitions and double layers, the ion-acoustic supersoliton solutions are also obtained for certain range of parameters in a magnetized three-component plasma model. The results show good agreement with Viking satellite observations of the solitary structures with density depletions in the auroral region of the Earth's magnetosphere.

  11. Ion acoustic solitons and supersolitons in a magnetized plasma with nonthermal hot electrons and Boltzmann cool electrons

    NASA Astrophysics Data System (ADS)

    Rufai, O. R.; Bharuthram, R.; Singh, S. V.; Lakhina, G. S.

    2014-08-01

    Arbitrary amplitude, ion acoustic solitons, and supersolitons are studied in a magnetized plasma with two distinct groups of electrons at different temperatures. The plasma consists of a cold ion fluid, cool Boltzmann electrons, and nonthermal energetic hot electrons. Using the Sagdeev pseudo-potential technique, the effect of nonthermal hot electrons on soliton structures with other plasma parameters is studied. Our numerical computation shows that negative potential ion-acoustic solitons and double layers can exist both in the subsonic and supersonic Mach number regimes, unlike the case of an unmagnetized plasma where they can only exist in the supersonic Mach number regime. For the first time, it is reported here that in addition to solitions and double layers, the ion-acoustic supersoliton solutions are also obtained for certain range of parameters in a magnetized three-component plasma model. The results show good agreement with Viking satellite observations of the solitary structures with density depletions in the auroral region of the Earth's magnetosphere.

  12. The design and implementation of the machine protection system for the Fermilab electron cooling facility

    SciTech Connect

    Warner, A.; Carmichael, L.; Carlson, K.; Crisp, J.; Goodwin, R.; Prost, L.; Saewert, G.; Shemyakin, A.; /Fermilab

    2009-05-01

    The Fermilab Recycler ring employs an electron cooler to store and cool 8.9-GeV antiprotons. The cooler is based on a 4.3-MV, 0.1-A, DC electrostatic accelerator for which current losses have to remain low ({approx}10{sup -5}) in order to operate reliably. The Machine Protection System (MPS) has been designed to interrupt the beam in a matter of 1-2 {micro}s when losses higher than a safe limit are detected, either in the accelerator itself or in the beam lines. This paper highlights the various diagnostics, electronics and logic that the MPS relies upon to successfully ensure that no damage be sustained to the cooler or the Recycler ring.

  13. Frequency-Domain Analysis of Diffusion-Cooled Hot-Electron Bolometer Mixers

    NASA Technical Reports Server (NTRS)

    Skalare, A.; McGrath, W. R.; Bumble, B.; LeDuc, H. G.

    1998-01-01

    A new theoretical model is introduced to describe heterodyne mixer conversion efficiency and noise (from thermal fluctuation effects) in diffusion-cooled superconducting hot-electron bolometers. The model takes into account the non-uniform internal electron temperature distribution generated by Wiedemann-Franz heat conduction, and accepts for input an arbitrary (analytical or experimental) superconducting resistance-versus- temperature curve. A non-linear large-signal solution is solved iteratively to calculate the temperature distribution, and a linear frequency-domain small-signal formulation is used to calculate conversion efficiency and noise. In the small-signal solution the device is discretized into segments, and matrix algebra is used to relate the heating modulation in the segments to temperature and resistance modulations. Matrix expressions are derived that allow single-sideband mixer conversion efficiency and coupled noise power to be directly calculated. The model accounts for self-heating and electrothermal feedback from the surrounding bias circuit.

  14. Electron cooling system in the booster synchrotron of the HIAF project

    NASA Astrophysics Data System (ADS)

    Mao, L. J.; Yang, J. C.; Xia, J. W.; Yang, X. D.; Yuan, Y. J.; Li, J.; Ma, X. M.; Yan, T. L.; Yin, D. Y.; Chai, W. P.; Sheng, L. N.; Shen, G. D.; Zhao, H.; Tang, M. T.

    2015-06-01

    The High Intensity heavy ion Accelerator Facility (HIAF) is a new accelerator complex under design at the Institute of Modern Physics (IMP). The facility is aiming at the production of high intensity heavy ion beams for a wide range of experiments in high energy density physics, nuclear physics, atomic physics and other applications. It consists of a superconducting electron-cyclotron-resonance ion source and an intense proton ion source, a linear accelerator, a 34 Tm booster synchrotron ring, a 43 Tm multifunction compression synchrotron ring, a 13 Tm high precision spectrometer ring and several experimental terminals. A magnetized electron cooling device is supposed to be used in the booster ring for decreasing the transverse emittance of injected beams. The conceptual design and main parameters of this cooler are presented in this paper.

  15. Cool Timepix - Electronic noise of the Timepix readout chip down to -125 °C

    NASA Astrophysics Data System (ADS)

    Schön, R.; Alfonsi, M.; van Bakel, N.; van Beuzekom, M.; Koffeman, E.

    2015-01-01

    The Timepix readout chip with its 65k pixels on a sensitive area of 14 mm×14 mm provides a fine spatial resolution for particle tracking or medical imaging. We explore the operation of Timepix in a dual-phase xenon environment (around -110 °C). Used in dual-phase xenon time projection chambers, e.g. for dark matter search experiments, the readout must have a sufficiently low detection limit for small energy deposits. We measured the electronic pixel noise of three bare Timepix chips. For the first time Timepix readout chips were cooled to temperatures as low as -125 °C. In this work, we present the results of analysing noise transition curves recorded while applying a well-defined charge to the pixel's input. The electronic noise reduces to an average of 99e-, a reduction of 23% compared to operation at room temperature.

  16. Issues concerning high current lower energy electron beams required for ion cooling between EBIS LINAC and booster

    SciTech Connect

    Hershcovitch,A.

    2009-03-01

    Some issues, regarding a low energy high current electron beam that will be needed for electron beam cooling to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster, are examined. Options for propagating such an electron beam, as well as the effect of neutralizing background plasma on electron and ion beam parameters are calculated. Computations and some experimental data indicate that none of these issues is a show stopper.

  17. Status of proof-of-principle experiment for coherent electron cooling

    SciTech Connect

    Pinayev I.; Belomestnykh, S.; Bengtsson, J.; Ben-Zvi, I.; Elizarov, A. et al

    2012-05-20

    Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o'clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters. We use a dogleg to merge the electron and ion beams. The ions 'imprint' their distribution into the electron beam via a space charge density modulation. The modulation is amplified in an FEL comprised of a 7-m long helical wiggler. The ions are co-propagating with electron beam through the FEL. The ion's average velocity is matched to the group velocity of the wave-packet of e-beam density modulation in the FEL. A three-pole wiggler at the exit of the FEL tune the phase of the wave-packet so the ion with the central energy experience the maximum of the e-beam density modulation, where electric field is zero. The time-of-flight dependence on ion's provides for the electrical field caused by the density modulation to reduce energy spread of the ion beam. The used electron beam is bent off the ion path and damped.

  18. The electromagnetic radiation fields of a relativistic electron avalanche with special attention to the origin of narrow bipolar pulses

    NASA Astrophysics Data System (ADS)

    Cooray, G. V.; Cooray, G. K.

    2011-12-01

    Gurevich et al. [1] postulated that the source of narrow bipolar pulses, a class of high energy pulses that occur during thunderstorms, could be a runaway electron avalanche driven by the intense electric fields of a thunderstorm. Recently, Watson and Marshall [2] used the modified transmission line model to test the mechanism of the source of narrow bipolar pulses. In a recent paper, Cooray and Cooray [3] demonstrated that the electromagnetic fields of accelerating charges could be used to evaluate the electromagnetic fields from electrical discharges if the temporal and spatial variation of the charges in the discharge is known. In the present study, those equations were utilized to evaluate the electromagnetic fields generated by a relativistic electron avalanche. In the analysis it is assumed that all the electrons in the avalanche are moving with the same speed. In other words, the growth or the decay of the number of electrons takes place only at the head of the avalanche. It is shown that the radiation is emanating only from the head of the avalanche where electrons are being accelerated. It is also shown that an analytical expression for the radiation field of the avalanche at any distance can be written directly in terms of the e-folding length of the avalanche. This makes it possible to extract directly the spatial variation of the e-folding length of the avalanche from the measured radiation fields. In the study this model avalanche was used to investigate whether it can be used to describe the measured electromagnetic fields of narrow bipolar pulses. The results obtained are in reasonable agreement with the two station data of Eack [4] for speeds of propagation around (2 - 2.5) x 10^8 m/s and when the propagation effects on the electric fields measured at the distant station is taken into account. [1] Gurevich et al. (2004), Phys. Lett. A., 329, pp. 348 -361. [2] Watson, S. S. and T. C. Marshall (2007), Geophys. Res. Lett., Vol. 34, L04816, doi: 10.1029/2006GL027426. [3] Cooray, V. and G. Cooray (2010), IEEE Transactions on Electromagnetic Compatibility, 52, No. 4, 944 - 955. [4] Eack, K. B. (2004), Geophys. Res. Lett., Vol. 31, L20102, doi: 10.1029/2005GL023975.

  19. Design of a Prototype EHD Air Pump for Electronic Chip Cooling Applications

    NASA Astrophysics Data System (ADS)

    Emmanouil, D. Fylladitakis; Antonios, X. Moronis; Konstantinos, Kiousis

    2014-05-01

    This paper presents the design, optimization and fabrication of an EHD air pump intended for high-power electronic chip cooling applications. Suitable high-voltage electrode configurations were selected and studied, in terms of the characteristics of the generated electric field, which play an important role in ionic wind flow. For this purpose, dedicated software is used to implement finite element analysis. Critical design parameters, such as the electric field intensity, wind velocity, current flow and power consumption are investigated. Two different laboratory prototypes are fabricated and their performances experimentally assessed. This procedure leads to the fabrication of a final prototype, which is then tested as a replacement of a typical fan for cooling a high power density electronic chip. To assist towards that end, an experimental thermal testing setup is designed and constructed to simulate the size of a personal computer's CPU core of variable power. The parametric study leads to the fabrication of experimental single-stage EHD pumps, the optimal design of which is capable of delivering an air flow of 51 CFM with an operating voltage of 10.5 kV. Finally, the theoretical and experimental results are evaluated and potential applications are proposed.

  20. Effect of electromagnetic shielding on electron beam-cured multi-walled carbon nanotubes/epoxy composites.

    PubMed

    Shin, Jin-Wook; Jeun, Joon-Pyo; Kang, Phil-Hyun

    2010-10-01

    In this study, the electromagnetic interference shielding properties of multi-walled carbon nanotubes/epoxy composites were investigated in the frequency region from 1 approximately 8 GHz (L, S and C bands). Electromagnetic shielding samples were fabricated using an electron beam. The electromagnetic shielding properties of these absorber specimens were measured by a network analyzer (Agilent, 4901A), and their fracture behavior was analyzed by scanning electron microscopy. It was found that the saturation conductance depends on the fraction of the multi-walled carbon nanotubes in the composite, which affects the initial permittivity. These results show that the dielectric loss is a dominant factor in the L, S, and C bands, and the resonance frequency of the composite increased with the increasing fraction of multi-walled carbon nanotubes. Finally, the reflection loss was calculated from the permeability and permittivity of these composites. Composite with 10 wt% multi-walled carbon nanotubes and 1.5 mm thickness showed a reflection loss below -20 dB in the L, S, and C bands. Therefore, it is believed that thin multi-walled carbon nanotubes/epoxy composites may be good candidates for microwave absorption applications. PMID:21137812

  1. Trajectories of electrons with large longitudinal momenta in the phase plane during surfatron acceleration by an electromagnetic wave

    SciTech Connect

    Mkrtichyan, G. S.

    2015-07-15

    The trajectories of electrons with large longitudinal momenta in the phase plane in the course of their surfatron acceleration by an electromagnetic wave propagating in space plasma across the external magnetic field are analyzed. Electrons with large longitudinal momenta are trapped immediately if the initial wave phase Ψ(0) on the particle trajectory is positive. For negative values of Ψ(0), no electrons trapping by the wave is observed over the available computational times. According to numerical calculations, the trajectories of trapped particles in the phase plane have a singular point of the stable focus type and the behavior of the trajectory corresponds to the motion in a complex nonstationary effective potential well. For some initial phases, electrons are confined in the region of the accelerating electric field for relatively short time, the energy gain being about 50–130% and more.

  2. Experimental observations of nonlinearly enhanced 2omega-UH electromagnetic radiation excited by steady-state colliding electron beams

    NASA Technical Reports Server (NTRS)

    Intrator, T.; Hershkowitz, N.; Chan, C.

    1984-01-01

    Counterstreaming large-diameter electron beams in a steady-state laboratory experiment are observed to generate transverse radiation at twice the upper-hybrid frequency (2omega-UH) with a quadrupole radiation pattern. The electromagnetic wave power density is nonlinearly enhanced over the power density obtained from a single beam-plasma system. Electromagnetic power density scales exponentially with beam energy and increases with ion mass. Weak turbulence theory can predict similar (but weaker) beam energy scaling but not the high power density, or the predominance of the 2omega-UH radiation peak over the omega-UH peak. Significant noise near the upper-hybrid and ion plasma frequencies is also measured, with normalized electrostatic wave energy density W(ES)/n(e)T(e) approximately 0.01.

  3. Efficient Coupling of Thermal Electron Bernstein Waves to the Ordinary Electromagnetic Mode on the National Spherical Torus Experiment (NSTX)

    SciTech Connect

    G. Taylor; P.C. Efthimion; B.P. LeBlanc; M.D. Carter; J.B. Caughman; J.B. Wilgen; J. Preinhaelter; R.W. Harvey; S.A. Sabbagh

    2005-02-02

    Efficient coupling of thermal electron Bernstein waves (EBW) to ordinary mode (Omode) electromagnetic radiation has been measured in plasmas heated by energetic neutral beams and high harmonic fast waves in the National Spherical Torus Experiment (NSTX) [M. Ono, S. Kaye, M. Peng, et al., Proceedings 17th IAEA Fusion Energy Conference (IAEA, Vienna, Austria, 1999), Vol.3, p. 1135]. The EBW to electromagnetic mode coupling efficiency was measured to be 0.8 {+-} 0.2, compared to a numerical EBW modeling prediction of 0.65. The observation of efficient EBW coupling to O-mode, in relatively good agreement with numerical modeling, is a necessary prerequisite for implementing a proposed high power EBW current drive system on NSTX.

  4. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Spin-dependent electron transport of a waveguide with Rashba spin-orbit coupling in an electromagnetic field

    NASA Astrophysics Data System (ADS)

    Xiao, Xian-Bo; Li, Xiao-Mao; Chen, Yu-Guang

    2009-12-01

    We investigate theoretically the spin-dependent electron transport in a straight waveguide with Rashba spin-orbit coupling (SOC) under the irradiation of a transversely polarized electromagnetic (EM) field. Spin-dependent electron conductance and spin polarization are calculated as functions of the emitting energy of electrons or the strength of the EM field by adopting the mode matching approach. It is shown that the spin polarization can be manipulated by external parameters when the strength of Rashba SOC is strong. Furthermore, a sharp step structure is found to exist in the total electron conductance. These results can be understood by the nontrivial Rashba subbands intermixing and the electron intersubband transition when a finite-range transversely polarized EM field irradiates a straight waveguide.

  5. Methods of beam cooling

    SciTech Connect

    Sessler, A.M.

    1996-02-01

    Diverse methods which are available for particle beam cooling are reviewed. They consist of some highly developed techniques such as radiation damping, electron cooling, stochastic cooling and the more recently developed, laser cooling. Methods which have been theoretically developed, but not yet achieved experimentally, are also reviewed. They consist of ionization cooling, laser cooling in three dimensions and stimulated radiation cooling.

  6. Strong neutrino cooling by cycles of electron capture and β- decay in neutron star crusts.

    PubMed

    Schatz, H; Gupta, S; Möller, P; Beard, M; Brown, E F; Deibel, A T; Gasques, L R; Hix, W R; Keek, L; Lau, R; Steiner, A W; Wiescher, M

    2014-01-01

    The temperature in the crust of an accreting neutron star, which comprises its outermost kilometre, is set by heating from nuclear reactions at large densities, neutrino cooling and heat transport from the interior. The heated crust has been thought to affect observable phenomena at shallower depths, such as thermonuclear bursts in the accreted envelope. Here we report that cycles of electron capture and its inverse, β(-) decay, involving neutron-rich nuclei at a typical depth of about 150 metres, cool the outer neutron star crust by emitting neutrinos while also thermally decoupling the surface layers from the deeper crust. This 'Urca' mechanism has been studied in the context of white dwarfs and type Ia supernovae, but hitherto was not considered in neutron stars, because previous models computed the crust reactions using a zero-temperature approximation and assumed that only a single nuclear species was present at any given depth. The thermal decoupling means that X-ray bursts and other surface phenomena are largely independent of the strength of deep crustal heating. The unexpectedly short recurrence times, of the order of years, observed for very energetic thermonuclear superbursts are therefore not an indicator of a hot crust, but may point instead to an unknown local heating mechanism near the neutron star surface. PMID:24291788

  7. Electronic spectra of jet-cooled isoindoline: Spectroscopic determination of energy difference between conformational isomers

    NASA Astrophysics Data System (ADS)

    Tanaka, Sei'ichi; Okuyama, Katsuhiko

    2010-04-01

    The electronic spectra of jet-cooled isoindoline between the electronic ground (S0) state and the ?? ? lowest-excited singlet state (S1) were observed by the fluorescence excitation and single-vibronic-level dispersed fluorescence methods. The low-frequency progression due to the puckering vibration appeared in both spectra. Analysis of dispersed spectra together with geometry optimization at the level of B3LYP/6-311+G(d) indicated the presence of conformational isomers possessing axial and equatorial N-H bonds with respect to the molecular plane. The 0-0 bands of the axial and equatorial conformers were measured at 37 022 and 36 761 cm-1, respectively. Three common levels in the S1 state accessible from the respective S0-state zero levels were observed. From their transition frequencies, the S0-state energy difference between the isomers was determined to be 47.70.2 cm-1, where the axial conformer was more stable. In the S1 state, the energy difference was 213.70.2 cm-1, and the equatorial conformer was more stable. The cause of switching from a stable conformation upon excitation is discussed in terms of the electron conjugation between the ?? orbital in benzene and the lone pair orbital of nitrogen.

  8. Progress towards an electron electric dipole moment measurement with laser-cooled atoms

    NASA Astrophysics Data System (ADS)

    Solmeyer, Neal

    This dissertation recounts the progress made towards a measurement of the electron electric dipole moment. The existence of a permanent electric dipole moment of any fundamental particle would imply that both time reversal and parity invariance are violated. If an electric dipole moment were measured within current experimental limits it would be the first direct evidence for physics beyond the standard model. For our measurement we use laser-cooled alkali atoms trapped in a pair of 1D optical lattices. The lattices run through three electric field plates so that the two groups of atoms see opposing electric fields. The measurement chamber is surrounded by a four layer mu-metal magnetic shield. Under electric field quantization, the atoms are prepared in a superposition of magnetic sublevels that is sensitive to the electron electric dipole moment in Ramsey-like spectroscopy. The experiment requires very large electric fields and very small magnetic fields. Engineering a system compatible with both of these goals simultaneously is not trivial. Searches for electric dipole moments using neutral atoms in optical lattices have much longer possible interaction times and potentially give more precise information about the inherent symmetry breaking than other methods. This comes at the cost of a higher sensitivity to magnetic fields and possible sources of error associated with the trapping light. If noise and systematic errors can be controlled to our design specifications our experiment will significantly improve the current experimental limit of the electron electric dipole moment.

  9. Electron cooling and finite potential drop in a magnetized plasma expansion

    NASA Astrophysics Data System (ADS)

    Martinez-Sanchez, M.; Navarro-Cavallé, J.; Ahedo, E.

    2015-05-01

    The steady, collisionless, slender flow of a magnetized plasma into a surrounding vacuum is considered. The ion component is modeled as mono-energetic, while electrons are assumed Maxwellian upstream. The magnetic field has a convergent-divergent geometry, and attention is restricted to its paraxial region, so that 2D and drift effects are ignored. By using the conservation of energy and magnetic moment of particles and the quasi-neutrality condition, the ambipolar electric field and the distribution functions of both species are calculated self-consistently, paying attention to the existence of effective potential barriers associated to magnetic mirroring. The solution is used to find the total potential drop for a set of upstream conditions, plus the axial evolution of various moments of interest (density, temperatures, and heat fluxes). The results illuminate the behavior of magnetic nozzles, plasma jets, and other configurations of interest, showing, in particular, in the divergent plasma the collisionless cooling of electrons, and the generation of collisionless electron heat fluxes.

  10. Inelastic electron transport through mesoscopic systems: Heating versus cooling and sequential tunneling versus cotunneling processes

    NASA Astrophysics Data System (ADS)

    Jiang, Feng; Jin, Jinshuang; Wang, Shikuan; Yan, YiJing

    2012-06-01

    Inelastic electron transport in quantum dot systems is studied via the hierarchical equations of motion combining a small polaron transformation approach, with differential conductance dI/dV˜V characteristics being evaluated accurately at the cotunneling level. We observe (i) the peak feature of phonon emission Franck-Condon sidebands to the zero-phonon peaks of both polaron and bipolaron in sequential electron transport; (ii) phonon absorption peaks occurring if the phonon temperature is sufficiently higher than that of the carrier electron; and (iii) the step feature of Raman sidebands in the cotunneling transport regime. We also evaluate the polaron transport response to a continuous-wave irradiation that induces bias-voltage oscillation. We observe, consistent with experimental results, that (iv) the photon-phonon-assisted tunneling enhances phonon absorptions while suppressing emissions. As the phonon absorption (emission) is associated with the process of absorbing (emitting) energy from (to) the phonon environment, an alternating or tailored field applied to contacts could be a practical means of cooling the mesoscopic quantum-transport device.

  11. Electron cooling and finite potential drop in a magnetized plasma expansion

    SciTech Connect

    Martinez-Sanchez, M.; Navarro-Cavallé, J.; Ahedo, E.

    2015-05-15

    The steady, collisionless, slender flow of a magnetized plasma into a surrounding vacuum is considered. The ion component is modeled as mono-energetic, while electrons are assumed Maxwellian upstream. The magnetic field has a convergent-divergent geometry, and attention is restricted to its paraxial region, so that 2D and drift effects are ignored. By using the conservation of energy and magnetic moment of particles and the quasi-neutrality condition, the ambipolar electric field and the distribution functions of both species are calculated self-consistently, paying attention to the existence of effective potential barriers associated to magnetic mirroring. The solution is used to find the total potential drop for a set of upstream conditions, plus the axial evolution of various moments of interest (density, temperatures, and heat fluxes). The results illuminate the behavior of magnetic nozzles, plasma jets, and other configurations of interest, showing, in particular, in the divergent plasma the collisionless cooling of electrons, and the generation of collisionless electron heat fluxes.

  12. OTR measurements and modeling of the electron beam optics at the E-cooling facility

    SciTech Connect

    Warner, A.; Burov, Alexey V.; Carlson, K.; Kazakevich, G.; Nagaitsev, S.; Prost, L.; Sutherland, M.; Tiunov, M.; /Fermilab /Novosibirsk, IYF

    2005-11-01

    Optics of the electron beam accelerated in the Pelletron, intended for the electron cooling of 8.9 GeV antiprotons in the Fermilab recycler storage ring, has been studied. The beam profile parameters were measured under the accelerating section using Optical Transition Radiation (OTR) monitor. The monitor employs a highly-reflective 2 inch-diameter aluminum OTR-screen with a thickness of 5 {micro}m and a digital CCD camera. The measurements were done in a pulse-signal mode in the beam current range of 0.03-0.8 A and at pulse durations ranging from 1 {micro}s to 4 {micro}s. Differential profiles measured in pulsed mode are compared with results obtained by modeling of the DC beam dynamics from the Pelletron cathode to the OTR monitor. The modeling was done with SAM, ULTRASAM and BEAM programs. An adjustment of the magnetic fields in the lenses of the accelerating section was done in the simulations. The simulated electron beam optics downstream of the accelerating section was in good agreement with the measurements made with pulsed beam.

  13. OTR Measurements and Modeling of the Electron Beam Optics at the E-Cooling Facility

    SciTech Connect

    Warner, A.; Burov, A.; Carlson, K.; Nagaitsev, S.; Prost, L.; Sutherland, M.; Kazakevich, G.; Tiunov, M.

    2006-03-20

    Optics of the electron beam accelerated in the Pelletron, intended for the electron cooling of 8.9 GeV antiprotons in the Fermilab recycler storage ring, has been studied. The beam profile parameters were measured under the accelerating section using Optical Transition Radiation (OTR) monitor. The monitor employs a highly-reflective 2 inch-diameter aluminum OTR-screen with a thickness of 5 {mu}m and a digital CCD camera. The measurements were done in a pulse-signal mode in the beam current range of 0.03-0.8 A and at pulse durations ranging from 1 {mu}s to 4 {mu}s. Differential profiles measured in pulsed mode are compared with results obtained by modeling of the DC beam dynamics from the Pelletron cathode to the OTR monitor. The modeling was done with SAM, ULTRASAM and BEAM programs. An adjustment of the magnetic fields in the lenses of the accelerating section was done in the simulations. The simulated electron beam optics downstream of the accelerating section was in good agreement with the measurements made with pulsed beam.

  14. PHYSICAL FOUNDATIONS OF QUANTUM ELECTRONICS: Vector potential of the electromagnetic field of a photon

    NASA Astrophysics Data System (ADS)

    Makshantsev, B. I.; Makshantsev, V. B.

    2001-09-01

    A solution of D'Alembert's equation for the vector potential of an electromagnetic field is found in the form of a wave packet, which does not spread in time and space. The expression obtained for the vector potential of a photon is used for the solution of some problems.

  15. 2-Dimensional CFD simulation and correlation development for optimization of fin heatsinks in electronic cooling

    NASA Astrophysics Data System (ADS)

    Yang, Jing; Wang, Li; Li, Huazhi

    2001-10-01

    CFD has penetrated into the field of electronic cooling for some time. Both parallel and staggered plate fin heatsinks are widely used in modern computers. This paper presents the ways to make most use of CFD in optimization design of those heatsinks: the flow and heat transfer of staggered and parallel plate fin heatsinks of various geometry were simulated by using Fluent 5.0 commercial CFD code. Based on 60 different simulation solutions, two correlations, concerning Nusselt number and friction factor as the functions of geometrical and operational parameters of the heatsinks were developed. The presentation parameter examination was also performed by comparing the numerical solutions with the analytical solutions of parallel plate arrays, showing that the correct parameters are used in the correlations.

  16. Air-Cooled Heat Exchanger for High-Temperature Power Electronics: Preprint

    SciTech Connect

    Waye, S. K.; Lustbader, J.; Musselman, M.; King, C.

    2015-05-06

    This work demonstrates a direct air-cooled heat exchanger strategy for high-temperature power electronic devices with an application specific to automotive traction drive inverters. We present experimental heat dissipation and system pressure curves versus flow rate for baseline and optimized sub-module assemblies containing two ceramic resistance heaters that provide device heat fluxes. The maximum allowable junction temperature was set to 175 deg.C. Results were extrapolated to the inverter scale and combined with balance-of-inverter components to estimate inverter power density and specific power. The results exceeded the goal of 12 kW/L and 12 kW/kg for power density and specific power, respectively.

  17. Effects of impurity seeding and charge non-neutrality on electromagnetic electron temperature gradient modes in a tokamak

    SciTech Connect

    Tangri, Varun; Singh, Raghvendra; Kaw, Predhiman

    2005-07-15

    A linear theory of toroidal electromagnetic electron temperature gradient (ETG) mode is reported. The effects such as Debye shielding, impurities, magnetic flutter perturbations {delta}B{sub perpendicular} and compressible parallel magnetic field perturbations {delta}B{sub parallel} are included in a fluid model. An eigenvalue equation is derived and solved analytically in local and semilocal limits. In the nonlocal limit, the eigenvalue equations are solved numerically. A comparison is also made of the linear thresholds obtained from this simple fluid model with previous gyrokinetic simulations. It is shown that the simple fluid theory results compare well with the thresholds obtained from gyrokinetic simulations.

  18. Apparatus and method for detecting electromagnetic radiation using electron photoemission in a micromechanical sensor

    DOEpatents

    Datskos, Panagiotis G.; Rajic, Slobodan; Datskou, Irene C.; Egert, Charles M.

    2002-01-01

    A micromechanical sensor and method for detecting electromagnetic radiation involve producing photoelectrons from a metal surface in contact with a semiconductor. The photoelectrons are extracted into the semiconductor, which causes photo-induced bending. The resulting bending is measured, and a signal corresponding to the measured bending is generated and processed. A plurality of individual micromechanical sensors can be arranged in a two-dimensional matrix for imaging applications.

  19. PHYSICAL FOUNDATIONS OF QUANTUM ELECTRONICS: Multiple reflection method for electromagnetic waves in layered dielectric structures

    NASA Astrophysics Data System (ADS)

    Morozov, G. V.; Maev, R. G.; Drake, G. W. F.

    2001-09-01

    Reflection and transmission of a plane electromagnetic wave propagating in a layered dielectric structure with an arbitrary number of layers of various thicknesses are investigated. For the general case of oblique incidence of the wave on this structure, the reflection and transmission coefficients are calculated for both TE and TM waves using a multiple reflection method. An algorithm to apply the obtained formulas for numerical and analytical calculations is suggested.

  20. [A Compact Source of Terahertz Radiation Based on Interaction of Electrons in Quantum Well with an Electromagnetic Wave of a Corrugated Waveguide].

    PubMed

    Shchurova, L Yu; Namiot, V A; Sarkisyan, D R

    2015-01-01

    Coherent sources of electromagnetic waves in the terahertz frequency range are very promising for various applications, including biology and medicine. In this paper we propose a scheme of a compact terahertz source, in which terahertz radiation is generated due to effective interaction of electrons in a quantum well with an electromagnetic wave of a corrugated waveguide. We have shown that the generation of electromagnetic waves with a frequency of 1012 sec(-1) and an output power of up to 25. mW is possible in the proposed scheme. PMID:26394479

  1. Radiation of de-excited electrons at large times in a strong electromagnetic plane wave

    NASA Astrophysics Data System (ADS)

    Kazinski, P. O.

    2013-12-01

    The late time asymptotics of the physical solutions to the Lorentz-Dirac equation in the electromagnetic external fields of simple configurations-the constant homogeneous field, the linearly polarized plane wave (in particular, the constant uniform crossed field), and the circularly polarized plane wave-are found. The solutions to the Landau-Lifshitz equation for the external electromagnetic fields admitting a two-parametric symmetry group, which include as a particular case the above mentioned field configurations, are obtained. Some general properties of the total radiation power of a charged particle are established. In particular, for a circularly polarized wave and constant uniform crossed fields, the total radiation power in the asymptotic regime is independent of the charge and the external field strength, when expressed in terms of the proper-time, and equals a half the rest energy of a charged particle divided by its proper-time. The spectral densities of the radiation power formed on the late time asymptotics are derived for a charged particle moving in the external electromagnetic fields of the simple configurations pointed above. This provides a simple method to verify experimentally that the charged particle has reached the asymptotic regime.

  2. Effect of forced oscillation at the channel entrance for enhanced cooling of components in electronic circuit pack channels

    NASA Astrophysics Data System (ADS)

    Azar, Kaveh

    1990-06-01

    An experimental investigation was conducted to study the effect of forced oscillation of the fluid entering an electronic circuit pack channel on component cooling. A realistic air cooled channel made of two vertically mounted circuit packs containing nine components each was employed. The experimental setup consisted of a channel with heated protrusions on one wall and a blade attached to a mechanical shaker at the inlet. Both natural and forced convection cooling were considered. The incoming fluid at the channel inlet was forced to oscillate at low frequencies. The results showed that forced oscillation improved component flow exposure and resulted in enhanced cooling of up to 15 percent in forced convection cases. Several parameters such as angle of shaker blade, channel height, and inlet velocity were examined and their contributions are highlighted.

  3. Measurement of the radiative cooling rates for high-ionization species of krypton using an electron beam ion trap

    PubMed

    Radtke; Biedermann; Fuchs; Fussmann; Beiersdorfer

    2000-02-01

    We describe a measurement of the radiative cooling rate for krypton made at the Berlin electron beam ion trap (EBIT). The EBIT was tuned to a charge-state distribution approaching the ionization balance of a plasma at a temperature of about 5 keV. To determine the cooling rate, we made use of EBIT's capabilities to sample a wide range of electron-beam energies and distinguish between different radiation channels. We have measured the x-ray emission from bremsstrahlung, radiative recombination, dielectronic recombination, and line radiation following electron-impact excitation. The dominant contribution to the cooling rate is made by the n=3-2, n=4-2, ellipsis x rays of the L-shell spectra of krypton, which produce more than 75% of the total radiation loss. A difference with theoretical calculations is noted for the measured total cooling rate. The predicted values are lower by a factor of 1.5-2, depending on the theoretical model. For our measurement of the cooling rate, we estimate an uncertainty interval of 22-30 %. PMID:11046483

  4. Radio-frequency electromagnetic field measurements for direct detection of electron Bernstein waves in a torus plasma

    SciTech Connect

    Yatsuka, Eiichi; Kinjo, Kiyotake; Morikawa, Junji; Ogawa, Yuichi

    2009-02-15

    To identify the mode-converted electron Bernstein wave (EBW) in a torus plasma directly, we have developed an interferometry system, in which a diagnostic microwave injected outside of the plasma column was directly detected with the probing antenna inserted into the plasma. In this work, plasma production and heating are achieved with 2.45 GHz, 2.5 kW electron cyclotron heating (ECH), whereas diagnostics are carried out with a lower power (10 W) separate frequency (1-2.1 GHz) microwave. Three components, i.e., two electromagnetic (toroidal and poloidal directions) and an electrostatic (if refractive index is sufficiently higher than unity, it corresponds to radial component), of ECRF electric field are simultaneously measured with three probing antennas, which are inserted into plasma. Selectivities of each component signal were checked experimentally. Excitation antennas have quite high selectivity of direction of linear polarization. As probing antennas for detecting electromagnetic components, we employed a monopole antenna with a length of 35 mm, and the separation of the poloidal (O-wave) and toroidal (X-wave) components of ECRF electric field could be available with this antenna. To detect EBW, which is an electrostatic wave, a small tip (1 mm) antenna was used. As the preliminary results, we detected signals that have three characteristics of EBW, i.e., short wavelength, backward propagation, and electrostatic.

  5. Electron acceleration by an obliquely propagating electromagnetic wave in the regime of validity of the Fokker-Planck-Kolmogorov approach

    NASA Technical Reports Server (NTRS)

    Hizanidis, Kyriakos; Vlahos, L.; Polymilis, C.

    1989-01-01

    The relativistic motion of an ensemble of electrons in an intense monochromatic electromagnetic wave propagating obliquely in a uniform external magnetic field is studied. The problem is formulated from the viewpoint of Hamiltonian theory and the Fokker-Planck-Kolmogorov approach analyzed by Hizanidis (1989), leading to a one-dimensional diffusive acceleration along paths of constant zeroth-order generalized Hamiltonian. For values of the wave amplitude and the propagating angle inside the analytically predicted stochastic region, the numerical results suggest that the diffusion probes proceeds in stages. In the first stage, the electrons are accelerated to relatively high energies by sampling the first few overlapping resonances one by one. During that stage, the ensemble-average square deviation of the variable involved scales quadratically with time. During the second stage, they scale linearly with time. For much longer times, deviation from linear scaling slowly sets in.

  6. FULL ELECTROMAGNETIC SIMULATION OF FREE-ELECTRON LASER AMPLIFIER PHYSICS VIA THE LORENTZ-BOOSTED FRAME APPROACH

    SciTech Connect

    Fawley, William M; Vay, Jean-Luc

    2009-04-29

    Numerical simulation of some systems containing charged particles with highly relativistic directed motion can by speeded up by orders of magnitude by choice of the proper Lorentz-boosted frame[1]. A particularly good example is that of short wavelength free-electron lasers (FELs) in which a high energy electron beam interacts with a static magnetic undulator. In the optimal boost frame with Lorentz factor gamma_F , the red-shifted FEL radiation and blue shifted undulator have identical wavelengths and the number of required time-steps (presuming the Courant condition applies) decreases by a factor of 2(gamma_F)**2 for fully electromagnetic simulation. We have adapted the WARP code [2]to apply this method to several FEL problems involving coherent spontaneous emission (CSE) from pre-bunched ebeams, including that in a biharmonic undulator.

  7. Electromagnetic simulation of electronic packaging designs (95-ERP-003). 1995 LDRD final report

    SciTech Connect

    Swegle, J.A.

    1996-05-01

    The primary focus of the project summarized in this report has been to evaluate the performance of the 3D, time-domain electromagnetic code DS13D in the simulation of structures used in microwave microelectronics circuits. We`ve adopted two test cases, coaxial and stripline transmission lines, for which well-known results are available so that results obtained with DS13D could be easily and accurately checked. Our goals have been three-fold: (1) To develop specialized mode-launching capabilities for single-mode signals typically found in test geometries and the diagnostics necessary to evaluate the performance of the code in modeling the propagation of those signals. (2) To analyze the effect of different zoning schemes on the accuracy with which the code models the propagation of signals through the geometries by checking against known analytic results and calculations performed with other codes. (3) To examine the effect of code modifications aimed at enhancing the accuracy of the simulations. The calculated transmission line impedance was chosen as the primary means of evaluating code performance. Since the lowest-order propagating modes for the test cases were transverse electromagnetic (TEM) modes, the computation of impedance was reasonably straightforward. Both time- and frequency-domain values (the latter obtained from the code output by post-processing with a discrete Fourier transform) were obtained and compared.

  8. Effect of Material Inhomogeneity on Thermal Performance of a Rheocast Aluminum Heatsink for Electronics Cooling

    NASA Astrophysics Data System (ADS)

    Payandeh, M.; Belov, I.; Jarfors, A. E. W.; Wessén, M.

    2016-05-01

    The relation between microstructural inhomogeneity and thermal conductivity of a rheocast component manufactured from two different aluminum alloys was investigated. The formation of two different primary α-Al particles was observed and related to multistage solidification process during slurry preparation and die cavity filling process. The microstructural inhomogeneity of the component was quantified as the fraction of α 1-Al particles in the primary Al phase. A high fraction of coarse solute-lean α 1-Al particles in the primary Al phase caused a higher thermal conductivity of the component in the near-to-gate region. A variation in thermal conductivity through the rheocast component of 10% was discovered. The effect of an inhomogeneous temperature-dependent thermal conductivity on the thermal performance of a large rheocast heatsink for electronics cooling in an operation environment was studied by means of simulation. Design guidelines were developed to account for the thermal performance of heatsinks with inhomogeneous thermal conductivity, as caused by the rheocasting process. Under the modeling assumptions, the simulation results showed over 2.5% improvement in heatsink thermal resistance when the higher conductivity near-to-gate region was located at the top of the heatsink. Assuming homogeneous thermo-physical properties in a rheocast heatsink may lead to greater than 3.5% error in the estimation of maximum thermal resistance of the heatsink. The variation in thermal conductivity within a large rheocast heatsink was found to be important for obtaining of a robust component design.

  9. Theory of hysteresis during electron heating of electromagnetic wave scattering by self-organized dust structures in complex plasmas

    NASA Astrophysics Data System (ADS)

    Tsytovich, Vadim; Gusein-zade, Namik; Ignatov, Alexander

    2015-07-01

    Dust structuring is a natural and universal process in complex plasmas. The scattering of electromagnetic waves by dust structures is governed by the factor of coherency, i.e., the total number of coherent electrons in a single structure. In the present paper, we consider how the factor of coherency changes due to additional pulse electron heating and show that it obeys a hysteresis. After the end of the pulse heating, the scattering intensity differs substantially from that before heating. There are three necessary conditions for scattering hysteresis: first, the radiation wavelength should be larger than the pattern (structure) size; second, the total number of coherent electrons confined by the structure should be large; and third, the heating pulse duration should be shorter than the characteristic time of dust structure formation. We present the results of numerical calculations using existing models of self-consistent dust structures with either positively or negatively charged dust grains. It is shown that, depending on the grain charge and the ionization rate, two types of hysteresis are possible: one with a final increase of the scattering and the other with a final decrease of the scattering. It is suggested that the hysteresis of coherent scattering can be used as a tool in laboratory experiments and that it can be a basic mechanism explaining the observed hysteresis in radar scattering by noctilucent clouds during active experiments on electron heating in mesosphere.

  10. Theory of hysteresis during electron heating of electromagnetic wave scattering by self-organized dust structures in complex plasmas

    SciTech Connect

    Tsytovich, Vadim; Gusein-zade, Namik; Ignatov, Alexander

    2015-07-15

    Dust structuring is a natural and universal process in complex plasmas. The scattering of electromagnetic waves by dust structures is governed by the factor of coherency, i.e., the total number of coherent electrons in a single structure. In the present paper, we consider how the factor of coherency changes due to additional pulse electron heating and show that it obeys a hysteresis. After the end of the pulse heating, the scattering intensity differs substantially from that before heating. There are three necessary conditions for scattering hysteresis: first, the radiation wavelength should be larger than the pattern (structure) size; second, the total number of coherent electrons confined by the structure should be large; and third, the heating pulse duration should be shorter than the characteristic time of dust structure formation. We present the results of numerical calculations using existing models of self-consistent dust structures with either positively or negatively charged dust grains. It is shown that, depending on the grain charge and the ionization rate, two types of hysteresis are possible: one with a final increase of the scattering and the other with a final decrease of the scattering. It is suggested that the hysteresis of coherent scattering can be used as a tool in laboratory experiments and that it can be a basic mechanism explaining the observed hysteresis in radar scattering by noctilucent clouds during active experiments on electron heating in mesosphere.

  11. Effects of suprathermal electrons on the proton temperature anisotropy in space plasmas: Electromagnetic ion-cyclotron instability

    NASA Astrophysics Data System (ADS)

    Shaaban, S. M.; Lazar, M.; Poedts, S.; Elhanbaly, A.

    2016-06-01

    In collision-poor plasmas from space, e.g., the solar wind and planetary magnetospheres, the kinetic anisotropy of the plasma particles is expected to be regulated by the kinetic instabilities. Driven by an excess of ion (proton) temperature perpendicular to the magnetic field (T_{perp}>T_{allel}), the electromagnetic ion-cyclotron (EMIC) instability is fast enough to constrain the proton anisotropy, but the observations do not conform to the instability thresholds predicted by the standard theory for bi-Maxwellian models of the plasma particles. This paper presents an extended investigation of the EMIC instability in the presence of suprathermal electrons which are ubiquitous in these environments. The analysis is based on the kinetic (Vlasov-Maxwell) theory assuming that both species, protons and electrons, may be anisotropic, and the EMIC unstable solutions are derived numerically providing an accurate description for conditions typically encountered in space plasmas. The effects of suprathermal populations are triggered by the electron anisotropy and the temperature contrast between electrons and protons. For certain conditions the anisotropy thresholds exceed the limits of the proton anisotropy measured in the solar wind considerably restraining the unstable regimes of the EMIC modes.

  12. The theoretical study on electronic structure and electromagnetic properties of α-MnO2 based on crystal defects

    NASA Astrophysics Data System (ADS)

    Duan, Yuping; Chen, Junlei; Zhang, Yahong; Wang, Tongmin

    2014-12-01

    First-principles calculations based on density functional theory (DFT) have been carried out to investigate the effects of crystal defects (intrinsic vacancy defects and ion doping) on the microwave dielectric response and the correlative electromagnetic properties of α-MnO2 systematically. The possible role of crystal defects in electromagnetic performance is studied utilizing density of states (DOS) and the bond length between the manganese and oxygen. Lattice distortion is induced by the introduction of crystal defects. The spin-electronic DOS demonstrates that Ni doping enhances the spin-polarization of MnO2, which indicates that the Ni-doped MnO2 possesses certain magnetic characteristic, which is helpful for magnetic loss. The emergence of a new defect mode, contributes to the relaxation polarization phenomenon, so as to enhance the dielectric loss ability. In addition, through the change of the bond length and pseudo gap width, it can be learned that the bond strength and covalency of Mn-O bonds are weakened, which increases the dielectric loss of MnO2. The results throw light on the exploration of theoretical research on the microwave absorbing properties of MnO2 with crystal defects.

  13. Damage effect and mechanism of the GaAs pseudomorphic high electron mobility transistor induced by the electromagnetic pulse

    NASA Astrophysics Data System (ADS)

    Xiao-Wen, Xi; Chang-Chun, Chai; Gang, Zhao; Yin-Tang, Yang; Xin-Hai, Yu; Yang, Liu

    2016-04-01

    The damage effect and mechanism of the electromagnetic pulse (EMP) on the GaAs pseudomorphic high electron mobility transistor (PHEMT) are investigated in this paper. By using the device simulation software, the distributions and variations of the electric field, the current density and the temperature are analyzed. The simulation results show that there are three physical effects, i.e., the forward-biased effect of the gate Schottky junction, the avalanche breakdown, and the thermal breakdown of the barrier layer, which influence the device current in the damage process. It is found that the damage position of the device changes with the amplitude of the step voltage pulse. The damage appears under the gate near the drain when the amplitude of the pulse is low, and it also occurs under the gate near the source when the amplitude is sufficiently high, which is consistent with the experimental results. Project supported by the National Basic Research Program of China (Grant No. 2014CB339900), and the Open Fund of Key Laboratory of Complex Electromagnetic Environment Science and Technology, China Academy of Engineering Physics (CAEP) (Grant No. 2015-0214.XY.K).

  14. The applicability range of different forms of the radiation friction force in the ultrarelativistic electron interaction with electromagnetic wave (exact solutions)

    NASA Astrophysics Data System (ADS)

    Bulanov, S. S.; Esirkepov, T. Zh; Kando, M.; Koga, J. K.; Bulanov, S. V.

    2013-02-01

    When the effects of radiation reaction dominate the interaction of electrons with intense laser pulses, the electron dynamics changes qualitatively. The adequate theoretical description of this regime becomes crucially important with the use of the radiation friction force either in the Lorentz-Abraham-Dirac form, which possess unphysical runaway solutions, or in the Landau-Lifshitz form, which is a perturbation valid for relatively low electromagnetic wave amplitude. The goal of the present paper is to find the limits of the Landau-Lifshitz radiation force applicability in terms of the electromagnetic wave amplitude and frequency.

  15. Association of electromagnetic methods to model printed circuit board in power electronic systems

    NASA Astrophysics Data System (ADS)

    Guena, A.; Costa, F.; Labarre, C.

    2003-05-01

    The aim of this paper is to model the printed connections in static power converters. An analytical technique, based on the transmission line theory has been proposed previously (Labarre et al., Eur. Phys. J. AP 3, 169 (1998)). This paper shows that this modeling technique, named the thin wire method (TWM) is well adapted to predict the behaviour of various configuration of printed circuit board with a ground plane: isolated microstrip lines exhibiting a constant or not width, parallel or non-parallel lines of any length. New analytical formulas are proposed in any layout configuration. However, the total circuit modeling needs to combine the features of different electromagnetic models: MTL, PEEC, CTL with a numerical technique: the two dimensional transmission line matrix method (TLM2D).

  16. Electronic tuning of magnetic permeability in Co2Z hexaferrite toward high frequency electromagnetic device miniaturization

    NASA Astrophysics Data System (ADS)

    Chen, Yajie; Daigle, Andrew; Fitchorov, Trifon; Hu, Bolin; Geiler, Michael; Geiler, Anton; Vittoria, C.; Harris, V. G.

    2011-05-01

    The magnetic and magnetostriction properties of Z-type cobalt-doped barium hexaferrite with perpendicular c-axis crystallographic texture are presented. The hexaferrite was utilized as a component in Co2Z/lead magnesium niobate-lead titanate multiferroic heterostructures whose tunability of permeability with electric field in terms of ferromagnetic resonance shift was supported by experiments and theoretical calculation. A permeability change of 16% was measured by an induced magnetic field of 38 Oe under the application of 6 kV/cm of electric field. These findings lay the foundation for the application of Z-type hexaferrites in tunable rf and microwave devices valued for sending, receiving, and manipulating electromagnetic signals.

  17. Relativistic Electron Precipitation Events Driven by Electromagnetic Ion-Cyclotron Waves

    NASA Technical Reports Server (NTRS)

    Khazanov, G.; Sibeck, D.; Tel’nikhin, A.; Kronberg, T.

    2014-01-01

    We adopt a canonical approach to describe the stochastic motion of relativistic belt electrons and their scattering into the loss cone by nonlinear EMIC waves. The estimated rate of scattering is sufficient to account for the rate and intensity of bursty electron precipitation. This interaction is shown to result in particle scattering into the loss cone, forming approx.10 s microbursts of precipitating electrons. These dynamics can account for the statistical correlations between processes of energization, pitch angle scattering, and relativistic electron precipitation events, that are manifested on large temporal scales of the order of the diffusion time approx. tens of minutes.

  18. Relativistic electron precipitation events driven by electromagnetic ion-cyclotron waves

    SciTech Connect

    Khazanov, G. Sibeck, D.; Tel'nikhin, A.; Kronberg, T.

    2014-08-15

    We adopt a canonical approach to describe the stochastic motion of relativistic belt electrons and their scattering into the loss cone by nonlinear EMIC waves. The estimated rate of scattering is sufficient to account for the rate and intensity of bursty electron precipitation. This interaction is shown to result in particle scattering into the loss cone, forming ∼10 s microbursts of precipitating electrons. These dynamics can account for the statistical correlations between processes of energization, pitch angle scattering, and relativistic electron precipitation events, that are manifested on large temporal scales of the order of the diffusion time ∼tens of minutes.

  19. Interaction of a two-dimensional electromagnetic pulse with an electron inhomogeneity in an array of carbon nanotubes in the presence of field inhomogeneity

    NASA Astrophysics Data System (ADS)

    Zhukov, Alexander V.; Bouffanais, Roland; Leblond, Hervé; Mihalache, Dumitru; Fedorov, Eduard G.; Belonenko, Mikhail B.

    2015-11-01

    In this study, we address the challenging problem of propagation of infrared electromagnetic two-dimensional bipolar pulses of extremely short duration in a heterogeneous array of semiconductor carbon nanotubes. Heterogeneity is defined here as a region of high electron density. The evolutions of the electromagnetic field and charge density in the sample are described by Maxwell's equations and the continuity equation respectively, wherein the inhomogeneity of the field along the nanotube axis is integrated and incorporated into the modeling framework. Our numerical solution to this problem shows the possibility of a stable propagation of two-dimensional electromagnetic pulses through a heterogeneous array of carbon nanotubes. This propagation of electromagnetic pulses is accompanied by a redistribution of the electron density in the sample. For the first time to the best of our knowledge, this latter effect is fully accounted for in our study. Specifically, we demonstrate that depending on the initial speed of the electromagnetic pulse two possible outcomes might ensue: either (i) the pulse overcomes the region of increased electron concentration, or alternatively (ii) it is reflected therefrom. As a result, a near-infrared pulse is transmitted, while the long-wavelength infrared pulse is reflected, on an obstacle that is much smaller than its wavelength.

  20. Particle-in-cell simulations of velocity scattering of an anisotropic electron beam by electrostatic and electromagnetic instabilities

    SciTech Connect

    Fu, X. R. Cowee, M. M.; Winske, D.; Liu, K.; Peter Gary, S.

    2014-04-15

    The velocity space scattering of an anisotropic electron beam (T{sub ⊥b}/T{sub ∥b}>1) flowing along a background magnetic field B{sub 0} through a cold plasma is investigated using both linear theory and 2D particle-in-cell simulations. Here, ⊥ and ∥ represent the directions perpendicular and parallel to B{sub 0}, respectively. In this scenario, we find that two primary instabilities contribute to the scattering in electron pitch angle: an electrostatic electron beam instability and a predominantly parallel-propagating electromagnetic whistler anisotropy instability. Our results show that at relative beam densities n{sub b}/n{sub e}≤0.05 and beam temperature anisotropies T{sub b⊥}/T{sub b∥}≤25, the electrostatic beam instability grows much faster than the whistler instabilities for a reasonably fast hot beam. The enhanced fluctuating fields from the beam instability scatter the beam electrons, slowing their average speed and increasing their parallel temperature, thereby increasing their pitch angles. In an inhomogeneous magnetic field, such as the geomagnetic field, this could result in beam electrons scattered out of the loss cone. After saturation of the electrostatic instability, the parallel-propagating whistler anisotropy instability shows appreciable growth, provided that the beam density and late-time anisotropy are sufficiently large. Although the whistler anisotropy instability acts to pitch-angle scatter the electrons, reducing perpendicular energy in favor of parallel energy, these changes are weak compared to the pitch-angle increases resulting from the deceleration of the beam due to the electrostatic instability.

  1. Hybrid two-dimensional Monte-Carlo electron transport in self-consistent electromagnetic fields

    SciTech Connect

    Mason, R.J.; Cranfill, C.W.

    1985-01-01

    The physics and numerics of the hybrid electron transport code ANTHEM are described. The need for the hybrid modeling of laser generated electron transport is outlined, and a general overview of the hybrid implementation in ANTHEM is provided. ANTHEM treats the background ions and electrons in a laser target as coupled fluid components moving relative to a fixed Eulerian mesh. The laser converts cold electrons to an additional hot electron component which evolves on the mesh as either a third coupled fluid or as a set of Monte Carlo PIC particles. The fluids and particles move in two-dimensions through electric and magnetic fields calculated via the Implicit Moment method. The hot electrons are coupled to the background thermal electrons by Coulomb drag, and both the hot and cold electrons undergo Rutherford scattering against the ion background. Subtleties of the implicit E- and B-field solutions, the coupled hydrodynamics, and large time step Monte Carlo particle scattering are discussed. Sample applications are presented.

  2. Random walk study of electron motion in helium in crossed electromagnetic fields

    NASA Technical Reports Server (NTRS)

    Englert, G. W.

    1972-01-01

    Random walk theory, previously adapted to electron motion in the presence of an electric field, is extended to include a transverse magnetic field. In principle, the random walk approach avoids mathematical complexity and concomitant simplifying assumptions and permits determination of energy distributions and transport coefficients within the accuracy of available collisional cross section data. Application is made to a weakly ionized helium gas. Time of relaxation of electron energy distribution, determined by the random walk, is described by simple expressions based on energy exchange between the electron and an effective electric field. The restrictive effect of the magnetic field on electron motion, which increases the required number of collisions per walk to reach a terminal steady state condition, as well as the effect of the magnetic field on electron transport coefficients and mean energy can be quite adequately described by expressions involving only the Hall parameter.

  3. Lorentz-Abraham-Dirac versus Landau-Lifshitz radiation friction force in the ultrarelativistic electron interaction with electromagnetic wave (exact solutions)

    NASA Astrophysics Data System (ADS)

    Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki; Koga, James K.; Bulanov, Stepan S.

    2011-11-01

    When the parameters of electron-extreme power laser interaction enter the regime of dominated radiation reaction, the electron dynamics changes qualitatively. The adequate theoretical description of this regime becomes crucially important with the use of the radiation friction force either in the Lorentz-Abraham-Dirac form, which possesses unphysical runaway solutions, or in the Landau-Lifshitz form, which is a perturbation valid for relatively low electromagnetic wave amplitude. The goal of the present paper is to find the limits of the Landau-Lifshitz radiation force applicability in terms of the electromagnetic wave amplitude and frequency. For this, a class of the exact solutions to the nonlinear problems of charged particle motion in the time-varying electromagnetic field is used.

  4. Lorentz-Abraham-Dirac versus Landau-Lifshitz radiation friction force in the ultrarelativistic electron interaction with electromagnetic wave (exact solutions).

    PubMed

    Bulanov, Sergei V; Esirkepov, Timur Zh; Kando, Masaki; Koga, James K; Bulanov, Stepan S

    2011-11-01

    When the parameters of electron-extreme power laser interaction enter the regime of dominated radiation reaction, the electron dynamics changes qualitatively. The adequate theoretical description of this regime becomes crucially important with the use of the radiation friction force either in the Lorentz-Abraham-Dirac form, which possesses unphysical runaway solutions, or in the Landau-Lifshitz form, which is a perturbation valid for relatively low electromagnetic wave amplitude. The goal of the present paper is to find the limits of the Landau-Lifshitz radiation force applicability in terms of the electromagnetic wave amplitude and frequency. For this, a class of the exact solutions to the nonlinear problems of charged particle motion in the time-varying electromagnetic field is used. PMID:22181534

  5. Lorentz-Abraham-Dirac versus Landau-Lifshitz radiation friction force in the ultrarelativistic electron interaction with electromagnetic wave (exact solutions)

    SciTech Connect

    Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki; Koga, James K.; Bulanov, Stepan S.

    2011-11-15

    When the parameters of electron-extreme power laser interaction enter the regime of dominated radiation reaction, the electron dynamics changes qualitatively. The adequate theoretical description of this regime becomes crucially important with the use of the radiation friction force either in the Lorentz-Abraham-Dirac form, which possesses unphysical runaway solutions, or in the Landau-Lifshitz form, which is a perturbation valid for relatively low electromagnetic wave amplitude. The goal of the present paper is to find the limits of the Landau-Lifshitz radiation force applicability in terms of the electromagnetic wave amplitude and frequency. For this, a class of the exact solutions to the nonlinear problems of charged particle motion in the time-varying electromagnetic field is used.

  6. Random walk of electrons in a gas in the presence of polarized electromagnetic waves: Genesis of a wave induced discharge

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Sudeep; Paul, Samit

    2009-10-01

    The average number of collisions N of seed electrons with neutral gas atoms during random walk in escaping from a given volume, in the presence of polarized electromagnetic waves, is found to vary as N =B(Λ /λ)2/[1+C(Λ /λ)]2, indicating a modification to the conventional field free square law N =A(Λ /λ)2, where Λ is the characteristic diffusion length and λ the mean free path. It is found that for the field free case A =1.5 if all the electrons originate at the center and is 1.25 if they are allowed to originate at any random point in the given volume. The B and C coefficients depend on the wave electric field and frequency. Predictions of true discharge initiation time τc can be made from the temporal evolution of seed electrons over a wide range of collision frequencies. For linearly polarized waves of 2.45 GHz and electric field in the range (0.6-1.0)×105 V/m, τc=5.5-1.6 ns for an unmagnetized microwave driven discharge at 1 Torr argon.

  7. Random walk of electrons in a gas in the presence of polarized electromagnetic waves: Genesis of a wave induced discharge

    SciTech Connect

    Bhattacharjee, Sudeep; Paul, Samit

    2009-10-15

    The average number of collisions N of seed electrons with neutral gas atoms during random walk in escaping from a given volume, in the presence of polarized electromagnetic waves, is found to vary as N=B({lambda}/{lambda}){sup 2}/[1+C({lambda}/{lambda})]{sup 2}, indicating a modification to the conventional field free square law N=A({lambda}/{lambda}){sup 2}, where {lambda} is the characteristic diffusion length and {lambda} the mean free path. It is found that for the field free case A=1.5 if all the electrons originate at the center and is 1.25 if they are allowed to originate at any random point in the given volume. The B and C coefficients depend on the wave electric field and frequency. Predictions of true discharge initiation time {tau}{sub c} can be made from the temporal evolution of seed electrons over a wide range of collision frequencies. For linearly polarized waves of 2.45 GHz and electric field in the range (0.6-1.0)x10{sup 5} V/m, {tau}{sub c}=5.5-1.6 ns for an unmagnetized microwave driven discharge at 1 Torr argon.

  8. Electron random walk and collisional crossover in a gas in presence of electromagnetic waves and magnetostatic fields

    SciTech Connect

    Bhattacharjee, Sudeep; Paul, Samit; Dey, Indranuj

    2013-04-15

    This paper deals with random walk of electrons and collisional crossover in a gas evolving toward a plasma, in presence of electromagnetic (EM) waves and magnetostatic (B) fields, a fundamental subject of importance in areas requiring generation and confinement of wave assisted plasmas. In presence of EM waves and B fields, the number of collisions N suffered by an electron with neutral gas atoms while diffusing out of the volume during the walk is significantly modified when compared to the conventional field free square law diffusion; N=1.5({Lambda}/{lambda}){sup 2}, where {Lambda} is the characteristic diffusion length and {lambda} is the mean free path. There is a distinct crossover and a time scale associated with the transition from the elastic to inelastic collisions dominated regime, which can accurately predict the breakdown time ({tau}{sub c}) and the threshold electric field (E{sub BD}) for plasma initiation. The essential features of cyclotron resonance manifested as a sharp drop in {tau}{sub c}, lowering of E{sub BD} and enhanced electron energy gain is well reproduced in the constrained random walk.

  9. Spectroscopy and dynamics of jet-cooled hydrazines and ammonia. II. Electron-impact dissociative ionization

    SciTech Connect

    Syage, J.A. )

    1992-11-01

    Dissociative-ionization cross sections, fragment appearance potentials, and fragment kinetic energies were measured for electron-impact excitation of jet-cooled NH[sub 3], hydrazine (N[sub 2]H[sub 4]), and monomethyl hydrazine (MMH) over an energy range of 10--270 eV. A data base of 35 parent and fragment ions is reported. All measurements were made in a crossed electron--molecular beam apparatus using pulsed extraction and time-of-flight mass detection to ensure field-free excitation and high collection efficiency for energetic ions. Cross sections for NH[sub 3] ionization are in good agreement with previous measurements except for ions with high kinetic energy (KE). These discrepancies are attributed to instrument-dependent KE detection efficiencies in the previous results. Cross section data have not been previously reported for N[sub 2]H[sub 4] and MMH. The measured cross sections for total ionization at 70 eV are 2.35 A[sup 2] (NH[sub 3]), 3.76 A[sup 2] (N[sub 2]H[sub 4]), and 4.20 A[sup 2] (MMH). KE distributions were measured by an ion deflection method and gave results consistent with time-of-flight peak-shape analysis. Mean KE values [lt][epsilon] [ital t][gt] are reported for all fragment ions studied. For 170-eV excitation of NH[sub 3], [lt][epsilon] [ital t][gt] varied from 0.026 eV (NH[sub 2][sup +]) to 1.4 eV (H[sup +]). The kinetic energies for N[sub 2]H[sub 4] and MMH fragment ions at similar excitation energies are typically much lower than for fragment ions from NH[sub 3], conforming to statistical arguments based on density of internal states. High resolution mass spectra were recorded for MMH in order to distinguish different fragment ions of the same unit mass.

  10. Electromagnetic cyclotron-loss-cone instability associated with weakly relativistic electrons

    NASA Technical Reports Server (NTRS)

    Wong, H. K.; Wu, C. S.; Ke, F. J.; Schneider, R. S.; Ziebell, L. F.

    1982-01-01

    The amplification of fast extraordinary mode waves at frequencies very close to the electron cyclotron frequency, due to the presence of a population of energetic electrons with a loss-cone type distribution, is studied. Low-energy background electrons are included in the analysis. Two types of loss-cone distribution functions are considered, and it is found that the maximum growth rates for both distribution functions are of the same order of magnitude. When the thermal effects of the energetic electrons are included in the dispersion equation, the real frequencies of the waves are lower than those obtained by using the cold plasma approximation. This effect tends to enhance the growth rate. An idealized case including a parallel electric field such that the distribution function of the trapped energetic electrons is modified is also considered. It is assumed that the parallel electric field can remove the low-energy background electrons away from the source region of radiation. Both these effects increase the growth rate.

  11. Petawatt laser-driven wakefield accelerator: All-optical electron injection via collision of laser pulses and radiation cooling of accelerated electron bunches.

    NASA Astrophysics Data System (ADS)

    Kalmykov, Serguei; Avitzour, Yoav; Yi, S. Austin; Shvets, Gennady

    2007-11-01

    We explore an electron injection into the laser wakefield accelerator (LWFA) using nearly head-on collision of the petawatt ultrashort (˜30 fs) laser pulse (driver) with a low- amplitude laser (seed) beam of the same duration and polarization. To eliminate the threat to the main laser amplifier we consider two options: (i) a frequency-shifted seed and (ii) a seed pulse propagating at a small angle to the axis. We show that the emission of synchrotron radiation due to betatron oscillations of trapped and accelerated electrons results in significant transverse cooling of quasi- monoenergetic accelerated electrons (with energies above 1 GeV). At the same time, the energy losses due to the synchrotron emission preserve the final energy spread of the electron beam. The ``dark current'' due to the electron trapping in multiple wake buckets and the effect of beam loading (wake destruction at the instant of beams collision) are discussed.

  12. Effects of Boundary Current on Electromagnetic Dispersion Characteristics for a Relativistic Electron Beam

    NASA Astrophysics Data System (ADS)

    Xiao, Jixiong; Zeng, Zhong; Xia, Donghui; Wang, Zhijiang; Liu, Changhai

    2016-01-01

    With betatron oscillation characteristics of the electron beam and ion channel effect taken into account, dispersion characteristics of electrostatic modes and TM modes for a relativistic electron beam guided by ion channel are studied. Dispersion relations are derived and solved numerically to investigate the dependence of the dispersion characteristics for electrostatic modes and TM modes on the betatron oscillation frequency and the ratio of the relativistic electron beam radius to the waveguide radius. The effects of the boundary current on the dispersion characteristic of the TM modes and the interaction between the betatron modes and TM modes are analyzed. When considering the boundary current, for a strong ion channel, a new low-frequency branch of the TM modes arises and the interaction frequency between the betatron modes and the TM01 modes is increased with the same parameters. supported by the National ITER Project Foundation of China (Nos. 2013GB106001 and 2013GB106003)

  13. Electromagnetic interchange-like mode and zonal flow in electron-magnetohydrodynamic plasma

    SciTech Connect

    Chakrabarti, Nikhil; Horiuchi, Ritoku

    2006-10-15

    A numerical simulation of the nonlinear state of interchange instability associated with electron inertia in an unmagnetized plasma is studied. It is shown that a self-consistent sheared transverse electron current flow is generated due to nonlinear mechanisms. This zonal flow can reduce the growth rate of the magnetic interchange-like instability and reach a steady state. The zonal flow generation mechanisms are discussed by truncated Fourier mode representation. In the truncated model, three mode equations are considered that have an exact analytic solution that matches well with the numerical solution. The effect of different boundary conditions in such investigations is also discussed.

  14. Formation of very hard electron and gamma-ray spectra of flat spectrum radio quasar in fast-cooling regime

    NASA Astrophysics Data System (ADS)

    Yan, Dahai; Zhang, Li; Zhang, Shuang-Nan

    2016-04-01

    In external Compton scenario, we investigate the formation of the very hard electron spectrum in the fast-cooling regime, using a time-dependent emission model. It is shown that a very hard electron distribution N^' }_e(γ^')∝ γ^' -p} with the spectral index p ˜ 1.3 is formed below the minimum energy of injection electron when inverse Compton scattering takes place in the Klein-Nishina regime, i.e., inverse Compton scattering of relativistic electrons on broad-line region radiation in flat spectrum radio quasars. This produces a very hard gamma-ray spectrum, and can reasonably explain the very hard Fermi-LAT spectrum of the flat spectrum radio quasar 3C 279 during the extreme gamma-ray flare in 2013 December.

  15. Electron-Driven Molecular Processes Induced in Biological Systems by Electromagnetic and Other Ionizing Sources

    NASA Astrophysics Data System (ADS)

    Baccarelli, I.; Gianturco, F. A.; Grandi, A.; Lucchese, R. R.; Sanna, N.

    We describe, and analyse in some detail, a selection of the most recent theoretical and computational models which attempt to explain, at the molecular level, the dynamics of metastable negative ion formation from biological molecules in the gas-phase. Such Transient Negative Ions (TNIs) are related to the nanoscopic nuclear dynamics presiding over the occurrence of irreversible damage in the biosystems through the many possible pathways leading to dissociative attachment decay of the initial TNI. We will review the theoretical approach we adopted to study electron-molecule collision as applied to systems of biological interest. The connection between the spatial symmetry of the metastable anion and its role during the dissociative electron attachment event is also discussed and analysed through several examples.

  16. Amplification of electromagnetic waves by a ring-beam distribution of moderately relativistic electrons

    NASA Technical Reports Server (NTRS)

    Shi, B. R.; Gaffey, J. D., Jr.; Wu, C. S.

    1986-01-01

    The possibility of a new mechanism for the excitation of unstable modes in cold background plasmas is indicated in this paper. These beam-cyclotron modes are excited by the presence of the ring-beam distribution of suprathermal electrons. The usual eigenmode excitation of a cold plasma is reviewed, and the new type of instability is examined using a single-harmonic approximation and multiharmonic treatment.

  17. Beam loss rates with an internal gas target in an electron-cooled storage ring Implications for luminosity optimization

    NASA Astrophysics Data System (ADS)

    Pollock, R. E.; Derenchuk, V.; Pei, X.; Sloan, T.; Sperisen, F.; Meyer, H.-O.; v. Przewoski, B.; Rinckel, T.; Pancella, P.; Ross, M. A.; Pitts, W. K.

    1993-06-01

    Measurements have been made in the Cooler ring at the Indiana University Cyclotron Facility (IUCF) of the mean lifetime of stored and electron-cooled proton beams in the presence of various target gas species at two ring locations differing in dispersion. A broad range of beam energy Tb, target atomic number Zt and thickness xt was employed. The loss (removal) cross sectionσ L per target atom, extracted from the lifetime measurement, exhibits a minimum for small xt which is found to scale with ( {Z t}/{T b}) 2. This behavior is expected because forward Coulomb scattering from target nuclei should be the dominant loss mechanism under the conditions of measurement. A marked increase in σ L for larger xt is attributed to emittance growth arising from multiple scattering in competition with the transverse cooling rate. Lattice dispersion at the target increases the contribution to beam heating by electrons in the target atoms and introduces an additional loss mechanism. From the measured σ L and beam lifetime, a time cycle may be selected which gives the optimum time-averaged luminosity for a given experiment. Scaling of σ L allows prediction of the optimum luminosity over the full operating regime of the cooling ring.

  18. Effect of Oblique Electromagnetic Ion Cyclotron Waves on Relativistic Electron Scattering: CRRES Based Calculation

    NASA Technical Reports Server (NTRS)

    Gamayunov, K. V.; Khazanov, G. V.

    2007-01-01

    We consider the effect of oblique EMIC waves on relativistic electron scattering in the outer radiation belt using simultaneous observations of plasma and wave parameters from CRRES. The main findings can be s ummarized as follows: 1. In 1comparison with field-aligned waves, int ermediate and highly oblique distributions decrease the range of pitc h-angles subject to diffusion, and reduce the local scattering rate b y an order of magnitude at pitch-angles where the principle absolute value of n = 1 resonances operate. Oblique waves allow the absolute va lue of n > 1 resonances to operate, extending the range of local pitc h-angle diffusion down to the loss cone, and increasing the diffusion at lower pitch angles by orders of magnitude; 2. The local diffusion coefficients derived from CRRES data are qualitatively similar to the local results obtained for prescribed plasma/wave parameters. Conseq uently, it is likely that the bounce-averaged diffusion coefficients, if estimated from concurrent data, will exhibit the dependencies similar to those we found for model calculations; 3. In comparison with f ield-aligned waves, intermediate and highly oblique waves decrease th e bounce-averaged scattering rate near the edge of the equatorial lo ss cone by orders of magnitude if the electron energy does not excee d a threshold (approximately equal to 2 - 5 MeV) depending on specified plasma and/or wave parameters; 4. For greater electron energies_ ob lique waves operating the absolute value of n > 1 resonances are more effective and provide the same bounce_averaged diffusion rate near the loss cone as fiel_aligned waves do.

  19. The theory of electro-magnetic radiation of electron transiting through the resonance-tunnel structure

    SciTech Connect

    Tkach, M.; Seti, Ju.; Voitsekhivska, O.; Fartushynsky, R.

    2009-12-14

    The quasi-stationary electron states are studied in the three-barrier resonance-tunnel structure which is the basic element of coherent quantum cascade lasers. In the models of rectangular and delta-barrier potentials there is established theory of evolution and collapse of double resonance complexes in a symmetric resonance-tunnel structure. The induced conductivity of nano-system is calculated within the both models. It is shown that the negative induced conductivity of three-barrier resonance-tunnel structure in delta-barrier model is dozens times smaller than more realistic magnitudes obtained within the rectangular potentials model.

  20. Investigation of the Electromagnetic Radiation Emitted by Sub-GeV Electrons in a Bent Crystal

    NASA Astrophysics Data System (ADS)

    Bandiera, L.; Bagli, E.; Germogli, G.; Guidi, V.; Mazzolari, A.; Backe, H.; Lauth, W.; Berra, A.; Lietti, D.; Prest, M.; De Salvador, D.; Vallazza, E.; Tikhomirov, V.

    2015-07-01

    The radiation emitted by 855 MeV electrons via planar channeling and volume reflection in a 30.5 -μ m -thick bent Si crystal has been investigated at the MAMI (Mainzer Mikrotron) accelerator. The spectral intensity was much more intense than for an equivalent amorphous material, and peaked in the MeV range in the case of channeling radiation. Differently from a straight crystal, also for an incidence angle larger than the Lindhard angle, the spectral intensity remains nearly as high as for channeling. This is due to volume reflection, for which the intensity remains high at a large incidence angle over the whole angular acceptance, which is equal to the bending angle of the crystal. Monte Carlo simulations demonstrated that incoherent scattering significantly influences both the radiation spectrum and intensity, either for channeling or volume reflection. In the latter case, it has been shown that incoherent scattering increases the radiation intensity due to the contribution of volume-captured particles. As a consequence, the experimental spectrum becomes a mixture of channeling and pure volume reflection radiations. These results allow a better understanding of the radiation emitted by electrons subjected to coherent interactions in bent crystals within a still-unexplored energy range, which is relevant for possible applications for innovative and compact x-ray or γ -ray sources.

  1. Tunability enhanced electromagnetic wiggler

    DOEpatents

    Schlueter, R.D.; Deis, G.A.

    1992-03-24

    The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles. 14 figs.

  2. Tunability enhanced electromagnetic wiggler

    DOEpatents

    Schlueter, Ross D.; Deis, Gary A.

    1992-01-01

    The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles.

  3. Integrated three-dimensional module heat exchanger for power electronics cooling

    DOEpatents

    Bennion, Kevin; Lustbader, Jason

    2013-09-24

    Embodiments discussed herein are directed to a power semiconductor packaging that removes heat from a semiconductor package through one or more cooling zones that are located in a laterally oriented position with respect to the semiconductor package. Additional embodiments are directed to circuit elements that are constructed from one or more modular power semiconductor packages.

  4. Electromagnetic probes of molecular motors in the electron transport chains of mitochondria and chloroplasts

    NASA Astrophysics Data System (ADS)

    Miller, J. H., Jr.; Nawarathna, D.; Vajrala, V.; Gardner, J.; Widger, W. R.

    2005-12-01

    We report on measurements of harmonics generated by whole cells, mitochondria, and chloroplasts in response to applied sinusoidal electric fields. The frequency- and amplitude-dependence of the induced harmonics exhibit features that correlate with physiological processes. Budding yeast (S. cerevisiae) cells produce numerous harmonics, the amplitudes of which depend strongly on frequency. When the second or third harmonic amplitude is plotted vs. applied frequency, we observe two peaks, around 3 kHz and 12 kHz, which are suppressed by respiratory inhibitors. We observe similar peaks when measuring the harmonic response of B. indicas, a relative of the mitochondrial ancestor. In uncoupled mitochondria, in which most of the electron transport chain is active but the ATP-synthase molecular turbine is inactive, only one (lower frequency) of the two peaks is present. Finally, we find that harmonics generated by chloroplasts depend dramatically on incident light, and vanish in the absence of light.

  5. Electromagnetic envelope solitons in ultrarelativistic inhomogeneous electron-positron-ion plasma

    SciTech Connect

    Du, Hong-E; Cheng, Li-Hong; Yu, Zi-Fa; Xue, Ju-Kui

    2014-08-15

    The nonlinear interaction of ultra-intense short laser beam and homogeneous/inhomogeneous electron-positron-ion (e-p-i) plasma is investigated. It is found that soliton solutions can exist in both homogeneous and inhomogeneous e-p-i plasma. The influence of the positron density, the phase velocity, the inhomogeneity nature, and the Hamiltonian of the system on the soliton structure is investigated. The evolution of envelope solitons in homogeneous e-p-i plasma is analyzed analytically by using a two-time-scale method and confirmed by numerical simulations. However, the soliton solutions can exist in inhomogeneous e-p-i plasma only when the positron density is high enough. Furthermore, the phase diagram for existing envelope soliton in positron density and phase velocity of the wave plane is obtained.

  6. Kinetic description of a free electron laser with an electromagnetic-wave wiggler and ion-channel guiding by using the Einstein coefficient technique

    NASA Astrophysics Data System (ADS)

    Mehdian, H.; AbasiRostami, S.; Hasanbeigi, A.

    2016-04-01

    A theoretical study of electron trajectories and gain in a free electron laser (FEL) with an electromagnetic-wave wiggler and ion-channel guiding is presented based on the Einstein coefficient method. The laser gain in the low-gain regime is obtained for the case of a cold tenuous relativistic electron beam, where the beam plasma frequency is much less than the radiation frequency propagating in this configuration. The resulting gain equation is analyzed numerically over a wide range of system parameters.

  7. Simulation of Multi-Spacecraft Observed Energetic Electron Injection By the Electromagnetic Field of a Transient, Localized Dipolarizing Flux Bundle

    NASA Astrophysics Data System (ADS)

    Gabrielse, C.; Angelopoulos, V.; Runov, A.; Turner, D. L.

    2014-12-01

    Energetic particle injections in the near-Earth plasma sheet are critical for supplying particles and energy to the radiation belts and ring current. Their origin, however, has been elusive due to the lack of equatorial, multi-point observations. After the launch of NASA's Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission in 2007, intense electric fields and elevated energetic particle fluxes have been observed to accompany localized (1-4 RE wide) bursty bulk flows and to propagate from the mid-tail regions (at geocentric radial distances R > 25RE) towards Earth, up to and at times inside of geosynchronous orbit (GEO, R=6.6RE). Motivated by these observations, we model simultaneous multi-point observations of electron injections using guiding center approximation in prescribed but realistic electric and magnetic fields to better understand the nature of their acceleration. Modeling of electron injections assuming a localized, impulsive, dipolarizing flux bundle and its accompanying electric field transported from mid-tail to near-Earth at bursty flow speeds successfully reproduces the observations at multiple spacecraft. The impulsive, localized nature of the earthward-propagating electromagnetic pulse with attending vortical/tailward flow is what makes this model particularly effective in reproducing both the injection and the dispersed decrease in energy flux often observed simultaneously with the injection but at lower energies (~10-30 keV). The results suggest that particle acceleration and transport towards the inner magnetosphere can be thought of as a superposition of individual bursts of varying intensity and cadence depending on global geomagnetic activity levels.

  8. Numerical calculation of dynamical friction in electron cooling systems, including magnetic field perturbations and finite time effects

    SciTech Connect

    Sobol, A.V.; Fedotov, A.; Bruhwiler, D.L.; Bell, G.I.; Litvinenko, V.

    2010-09-24

    The orders-of-magnitude higher luminosities required by future electron-ion collider concepts require a dissipative force to counteract the numerous factors acting to gradually increase the phase space volume of relativistic ion beams. High-energy electron cooling systems could provide the necessary dissipation via dynamical friction, but will have to be designed for new parameter regimes. It is expected that magnetic field errors, finite interaction time and other effects will reduce the dynamical friction and hence increase the cooling time, so improved understanding of the underlying dynamics is important. We present a generalized form of the classical field-free friction force equation, which conveniently captures some of these effects. Previous work (Bell et al 2008 J. Comput. Phys. 227 8714) shows both numerical and conceptual subtleties associated with undersampling of strong collisions, and we present a rigorous mathematical treatment of such difficulties, based on the use of a modified Pareto distribution for the electron-ion impact parameters. We also present a very efficient numerical algorithm for calculating the dynamical friction on a single ion in the field free case. For the case of arbitrary magnetic field errors, we present numerical simulation results, showing agreement with our generalized friction force formula.

  9. Nonlinear quantum theory of stimulated Cherenkov radiation of transverse electromagnetic waves from a low-density relativistic electron beam in a dielectric medium

    SciTech Connect

    Bobylev, Yu. B.; Kuzelev, M. V.

    2012-06-15

    A nonlinear quantum theory of stimulated Cherenkov radiation of transverse electromagnetic waves from a low-density relativistic electron beam in an isotropic dielectric medium is presented. A quantum model based on the Klein-Gordon equation is used. The growth rates of beam instabilities caused by the effect of stimulated Cherenkov radiation have been determined in the linear approximation. Mechanisms of the nonlinear saturation of relativistic quantum Cherenkov beam instabilities have been analyzed and the corresponding analytical solutions have been obtained.

  10. Experimental investigation on flow and heat transfer performance of a novel heat fin-plate radiator for electronic cooling

    NASA Astrophysics Data System (ADS)

    Peng, Hao; Ling, Xiang

    2009-10-01

    Within the electronics industry, high degree of integration and enhanced performance has led to high heat dissipation electronic devices. This has identified the future development of very high heat flux components. In this paper, a novel and high efficient diffusion welded heat fin-plate radiator (HFPR) was proposed and designed. Various parameters affect the thermal performance of HFPR. The effect of three parameters: the working fluid filling ratios (8% < FR < 70%), the vacuum degrees (0.001 Pa < VD < 0.1 Pa), and the air flow velocities (0.5 m/s < u < 6 m/s) were investigated experimentally. Using distilled water and ethanol as working fluids, a series of tests were carried out to find the influence of the above parameters on steady-state heat transfer characteristics of HFPR. The experimental results indicated that the filling ratio and vacuum degree had a significant influence on thermal performance of HFPR. Also compared with cooling performance using distilled water and ethanol, the HFPR cooling component using distilled water had a stronger heat dissipation capacity for the same filling ratio. The results also can provide a basis for optimal design of HFPR structure.

  11. Quantum logic readout and cooling of a single dark electron spin

    NASA Astrophysics Data System (ADS)

    Shi, Fazhan; Zhang, Qi; Naydenov, Boris; Jelezko, Fedor; Du, Jiangfeng; Reinhard, Friedemann; Wrachtrup, Jörg

    2013-05-01

    We study a single dark N2 electron spin defect in diamond, which is magnetically coupled to a nearby nitrogen-vacancy (NV) center. We perform pulsed electron spin resonance on this single spin by mapping its state to the NV center spin and optically reading out the latter. Moreover, we show that the NV center's spin polarization can be transferred to the electron spin by combined two decoupling control-NOT gates. These two results allow us to extend the NV center's two key properties—optical spin polarization and detection—to any electron spin in its vicinity. This enables dark electron spins to be used as local quantum registers and engineerable memories.

  12. Giant electromagnetic vortex and MeV monoenergetic electrons generated by short laser pulses in underdense plasma near quarter critical density region

    SciTech Connect

    Zhidkov, Alexei; Nemoto, Koshichi; Nayuki, Takuya; Oishi, Yuji; Fuji, Takashi

    2007-07-15

    Very efficient generation of monoenergetic, about 1 MeV, electrons from underdense plasma with its electron density close to the critical, when irradiated by an intense femtosecond laser pulse, is found via two dimensional particle-in-cell simulation. The stimulated Raman scattering of a laser pulse with frequency {omega}{<=}2{omega}{sub plmax} gives rise to a giant electromagnetic vortex. In contrast to electron acceleration by the well-known laser pulse wake, injected plasma electrons are accelerated up to vortex ponderomotive potential forming a quite monoenergetic distribution. A relatively high charge of such an electron source makes very efficient generation of soft {gamma} rays with h{omega}>300 keV.

  13. Contributions to the second workshop on medium energy electron cooling - MEEC96

    SciTech Connect

    MacLachlan, J.

    1997-09-01

    MEEC96 was a workshop devoted primarily to discussion within four working groups, not a mini-conference of prepared reports. Therefore, although there are contributions bearing the name of a single author, much of what was learned came in extemporaneous discussion of the issues posed to the participants. The original plan to produce formal proceedings has been dropped because of the limited number of participants willing to write up their own contributions and because of the difficulty of converting free-wheeling discussion to the written word. The premsise for the 1996 gathering was to set a critique of Fermilab`s R&D effort at cooling a ring of 8 GeV {bar p}`s. Separate abstracts have been submitted to the energy database for contributions to this workshop.

  14. A modified Bitter-type electromagnet and control system for cold atom experiments

    SciTech Connect

    Luan, Tian; Zhou, Tianwei; Chen, Xuzong; Ma, Zhaoyuan

    2014-02-15

    We present a modified Bitter-type electromagnet which features high magnetic field, fine electronic properties and efficient heat removal. The electromagnet is constructed from a stack of copper layers separated by mica layers that have the same shape. A distinctive design of cooling channels on the insulating layers and the parallel ducts between the layers ensures low resistance for cooling water to flow. A continuous current control system is also made to regulate the current through the electromagnet. In our experiment, versatile electromagnets are applied to generate magnetic field and gradient field. From our measurements, a peak magnetic field of 1000 G and a peak gradient field of 80 G/cm are generated in the center of the apparatuses which are 7 cm and 5 cm away from the edge of each electromagnet with a current of 230 A and 120 A, respectively. With the effective feedback design in the current control system and cooling water flow of 3.8 l/min, the stability of the current through the electromagnets can reach 10{sup −5}.

  15. Development of an electric field application system with transparent electrodes towards the electron EDM measurement with laser-cooled Fr atoms

    NASA Astrophysics Data System (ADS)

    Ishikawa, Taisuke; Ando, Shun; Aoki, Takahiro; Arikawa, Hiroshi; Harada, Ken-Ichi; Hayamizu, Tomohiro; Inoue, Takeshi; Itoh, Masatoshi; Kawamura, Hirokazu; Kato, Ko; Sakamoto, Kosuke; Uchiyama, Aiko; Sakemi, Yasuhiro

    2014-09-01

    The permanent electric dipole moment (EDM) of elementary particles is a good probe for new physics beyond the standard model. Since the francium (Fr) atom has a large enhancement factor of the electron EDM and laser-cooled atoms can have long coherence times, we plan to utilize laser-cooled Fr atoms for the electron EDM search experiment. Besides, a strong electric field is one of key issues for the EDM experiment. Recently, we have embarked on a development of the electric field application system with transparent electrodes coated by tin-doped indium oxide (ITO). The ITO electrodes break the difficulty in the coexistence of electrodes with several cooling laser lights. The actual electric field applied to the atom is evaluated by measuring the dc Stark shift for the laser-cooled rubidium atoms. In this presentation, the present status of the electric field application system will be reported. The permanent electric dipole moment (EDM) of elementary particles is a good probe for new physics beyond the standard model. Since the francium (Fr) atom has a large enhancement factor of the electron EDM and laser-cooled atoms can have long coherence times, we plan to utilize laser-cooled Fr atoms for the electron EDM search experiment. Besides, a strong electric field is one of key issues for the EDM experiment. Recently, we have embarked on a development of the electric field application system with transparent electrodes coated by tin-doped indium oxide (ITO). The ITO electrodes break the difficulty in the coexistence of electrodes with several cooling laser lights. The actual electric field applied to the atom is evaluated by measuring the dc Stark shift for the laser-cooled rubidium atoms. In this presentation, the present status of the electric field application system will be reported. This work is supported by Grants-in-Aid for Scientific Research (No. 26220705) and Tohoku University's Focused Research Project.

  16. Photodetachment, electron cooling, and recombination, in a series of neat aliphatic room temperature ionic liquids

    NASA Astrophysics Data System (ADS)

    Molins i Domenech, Francesc; Healy, Andrew T.; Blank, David A.

    2015-08-01

    Transient absorption following photodetachment of a series of neat methyl-alkyl-pyrrolidinium bis(trifluoromethylsulfonyl)amides at 6.20 eV was measured with sub-picosecond time resolution in the visible and near-IR portions of the spectrum. This series spans the onset of structuring in the liquids in the form of polarity alternation. Excitation promotes the electron into a delocalized state with a very large reactive radius. Strong transient absorption is observed in the visible spectrum with a ˜700 fs lifetime, and much weaker, long-lived absorption is observed in the near-IR spectrum. Absorption in the visible is shown to be consistent with the hole, and absorption in the near-IR is assigned to the free solvated electron. Yield of free electrons is estimated at ˜4%, is insensitive to the size of the cation, and is determined in less than 1 ps. Solvation of free electrons depends strongly on the size of the cation and correlates well with the viscosity of the liquid. In addition to radiolytic stability of the aliphatic cations, ultrafast, efficient recombination of separated charge in NTf2 - based ionic liquids following photo-excitation near the band-gap may prevent subsequent reactive damage associated with anions.

  17. Photodetachment, electron cooling, and recombination, in a series of neat aliphatic room temperature ionic liquids.

    PubMed

    Molins i Domenech, Francesc; Healy, Andrew T; Blank, David A

    2015-08-14

    Transient absorption following photodetachment of a series of neat methyl-alkyl-pyrrolidinium bis(trifluoromethylsulfonyl)amides at 6.20 eV was measured with sub-picosecond time resolution in the visible and near-IR portions of the spectrum. This series spans the onset of structuring in the liquids in the form of polarity alternation. Excitation promotes the electron into a delocalized state with a very large reactive radius. Strong transient absorption is observed in the visible spectrum with a ∼700 fs lifetime, and much weaker, long-lived absorption is observed in the near-IR spectrum. Absorption in the visible is shown to be consistent with the hole, and absorption in the near-IR is assigned to the free solvated electron. Yield of free electrons is estimated at ∼4%, is insensitive to the size of the cation, and is determined in less than 1 ps. Solvation of free electrons depends strongly on the size of the cation and correlates well with the viscosity of the liquid. In addition to radiolytic stability of the aliphatic cations, ultrafast, efficient recombination of separated charge in NTf2 (-) based ionic liquids following photo-excitation near the band-gap may prevent subsequent reactive damage associated with anions. PMID:26277144

  18. Dynamic changes of emitting electron distribution in the jet of 3C 279: signatures of acceleration and cooling

    NASA Astrophysics Data System (ADS)

    Yan, Dahai; He, Jianjian; Liao, Jinyuan; Zhang, Li; Zhang, Shuang-Nan

    2016-02-01

    We study the dynamic changes of electron energy distribution (EED) through systematically analysing the quasi-simultaneous spectral energy distributions (SEDs) of the flat spectrum radio quasar 3C 279 in different states. With Markov chain Monte Carlo technique we model fourteen SEDs of 3C 279 using a leptonic model with a three-parameter log-parabola EED. The 14 SEDs can be satisfactorily fitted with the one-zone leptonic model. The observed γ rays in 13 states are attributed to Compton scattering of external infrared photons from a surrounding dusty torus. The curved γ ray spectrum observed during 2014 2-8 April is well explained by the external Compton of dust radiation. It is found that there is a clear positive correlation between the curvature parameter b of the EED and the electron peak energy γ ^' }_pk. No significant correlation between b and the synchrotron peak frequency νs is found, due to the varied product of Doppler factor and fluid magnetic field from state to state. We interpret the correlation of b-γ ^' }_pk in a stochastic acceleration scenario. This positive correlation is in agreement with the prediction in the stage when the balance between acceleration and radiative cooling of the electrons is nearly established in the case of the turbulence spectral index q = 2.

  19. Combining nanocalorimetry and dynamic transmission electron microscopy for in situ characterization of materials processes under rapid heating and cooling.

    PubMed

    Grapes, Michael D; LaGrange, Thomas; Friedman, Lawrence H; Reed, Bryan W; Campbell, Geoffrey H; Weihs, Timothy P; LaVan, David A

    2014-08-01

    Nanocalorimetry is a chip-based thermal analysis technique capable of analyzing endothermic and exothermic reactions at very high heating and cooling rates. Here, we couple a nanocalorimeter with an extremely fast in situ microstructural characterization tool to identify the physical origin of rapid enthalpic signals. More specifically, we describe the development of a system to enable in situ nanocalorimetry experiments in the dynamic transmission electron microscope (DTEM), a time-resolved TEM capable of generating images and electron diffraction patterns with exposure times of 30 ns-500 ns. The full experimental system consists of a modified nanocalorimeter sensor, a custom-built in situ nanocalorimetry holder, a data acquisition system, and the DTEM itself, and is capable of thermodynamic and microstructural characterization of reactions over a range of heating rates (10(2) K/s-10(5) K/s) accessible by conventional (DC) nanocalorimetry. To establish its ability to capture synchronized calorimetric and microstructural data during rapid transformations, this work describes measurements on the melting of an aluminum thin film. We were able to identify the phase transformation in both the nanocalorimetry traces and in electron diffraction patterns taken by the DTEM. Potential applications for the newly developed system are described and future system improvements are discussed. PMID:25173298

  20. Combining nanocalorimetry and dynamic transmission electron microscopy for in situ characterization of materials processes under rapid heating and cooling

    SciTech Connect

    Grapes, Michael D.; LaGrange, Thomas; Reed, Bryan W.; Campbell, Geoffrey H.; Friedman, Lawrence H.; LaVan, David A.; Weihs, Timothy P.

    2014-08-15

    Nanocalorimetry is a chip-based thermal analysis technique capable of analyzing endothermic and exothermic reactions at very high heating and cooling rates. Here, we couple a nanocalorimeter with an extremely fast in situ microstructural characterization tool to identify the physical origin of rapid enthalpic signals. More specifically, we describe the development of a system to enable in situ nanocalorimetry experiments in the dynamic transmission electron microscope (DTEM), a time-resolved TEM capable of generating images and electron diffraction patterns with exposure times of 30 ns–500 ns. The full experimental system consists of a modified nanocalorimeter sensor, a custom-built in situ nanocalorimetry holder, a data acquisition system, and the DTEM itself, and is capable of thermodynamic and microstructural characterization of reactions over a range of heating rates (10{sup 2} K/s–10{sup 5} K/s) accessible by conventional (DC) nanocalorimetry. To establish its ability to capture synchronized calorimetric and microstructural data during rapid transformations, this work describes measurements on the melting of an aluminum thin film. We were able to identify the phase transformation in both the nanocalorimetry traces and in electron diffraction patterns taken by the DTEM. Potential applications for the newly developed system are described and future system improvements are discussed.

  1. Combining nanocalorimetry and dynamic transmission electron microscopy for in situ characterization of materials processes under rapid heating and cooling

    NASA Astrophysics Data System (ADS)

    Grapes, Michael D.; LaGrange, Thomas; Friedman, Lawrence H.; Reed, Bryan W.; Campbell, Geoffrey H.; Weihs, Timothy P.; LaVan, David A.

    2014-08-01

    Nanocalorimetry is a chip-based thermal analysis technique capable of analyzing endothermic and exothermic reactions at very high heating and cooling rates. Here, we couple a nanocalorimeter with an extremely fast in situ microstructural characterization tool to identify the physical origin of rapid enthalpic signals. More specifically, we describe the development of a system to enable in situ nanocalorimetry experiments in the dynamic transmission electron microscope (DTEM), a time-resolved TEM capable of generating images and electron diffraction patterns with exposure times of 30 ns-500 ns. The full experimental system consists of a modified nanocalorimeter sensor, a custom-built in situ nanocalorimetry holder, a data acquisition system, and the DTEM itself, and is capable of thermodynamic and microstructural characterization of reactions over a range of heating rates (102 K/s-105 K/s) accessible by conventional (DC) nanocalorimetry. To establish its ability to capture synchronized calorimetric and microstructural data during rapid transformations, this work describes measurements on the melting of an aluminum thin film. We were able to identify the phase transformation in both the nanocalorimetry traces and in electron diffraction patterns taken by the DTEM. Potential applications for the newly developed system are described and future system improvements are discussed.

  2. Neutrinos from SN 1987A - Implications for cooling of the nascent neutron star and the mass of the electron antineutrino

    NASA Technical Reports Server (NTRS)

    Loredo, Thomas J.; Lamb, Don Q.

    1989-01-01

    Data on neutrinos from SN 1987A are compared here with parameterized models of the neutrino emission using a consistent and straightforward statistical methodology. The empirically measured detector background spectra are included in the analysis, and the data are compared with a much wider variety of neutrino emission models than was explored previously. It is shown that the inferred neutrino emission model parameters are strongly correlated. The analysis confirms that simple models of the neutrino cooling of the nascent neutron star formed by the SN adequately explain the data. The inferred radius and binding energy of the neutron star are in excellent agreement with model calculations based on a wide range of equations of state. The results also raise the upper limit of the electron antineutrino rest mass to roughly 25 eV at the 95 percent confidence level, roughly 1.5-5 times higher than found previously.

  3. The development of a room temperature electron cyclotron resonance ion source (Lanzhou electron cyclotron resonance ion source No. 4) with evaporative cooling technology at Institute of Modern Physics

    SciTech Connect

    Lu, W. Sun, L. T.; Qian, C.; Feng, Y. C.; Ma, H. Y.; Zhang, X. Z.; Ma, B. H.; Zhao, H. W.; Guo, J. W.; Fang, X.; Yang, Y.; Xiong, B.; Guo, S. Q.; Ruan, L.

    2015-04-15

    LECR4 (Lanzhou electron cyclotron resonance ion source No. 4) has been successfully constructed at IMP and has also been connected with the Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ) systems. These source magnet coils are cooled through evaporative cooling technology, which is the first attempt with an ECR ion source in the world. The maximum mirror field is 2.5 T (with iron plug) and the effective plasma chamber volume is 1.2 l. It was designed to be operated at 18 GHz and aimed to produce intense multiple charge state heavy ion beams for the linear injector project SSC-Linac at IMP. In February 2014, the first analyzed beam at 18 GHz was extracted. During about three months’ commissioning, some outstanding results have been achieved, such as 1.97 emA of O{sup 6+}, 1.7 emA of Ar{sup 8+}, 1.07 emA of Ar{sup 9+}, and 118 euA of Bi{sup 28+}. The source has also successfully delivered O{sup 5+} and Ar{sup 8+} ion beams for RFQ commissioning in April 2014. This paper will give a brief overview of the design of LECR4. Then, the latest results of this source at 18 GHz will be presented.

  4. Neutrino signal of electron-capture supernovae from core collapse to cooling.

    PubMed

    Hüdepohl, L; Müller, B; Janka, H-T; Marek, A; Raffelt, G G

    2010-06-25

    An 8.8M{⊙} electron-capture supernova was simulated in spherical symmetry consistently from collapse through explosion to essentially complete deleptonization of the forming neutron star. The evolution time (∼9  s) is short because high-density effects suppress our neutrino opacities. After a short phase of accretion-enhanced luminosities (∼200  ms), luminosity equipartition among all species becomes almost perfect and the spectra of ν{e} and ν{μ,τ} very similar, ruling out the neutrino-driven wind as r-process site. We also discuss consequences for neutrino flavor oscillations. PMID:20867357

  5. Neutrino Signal of Electron-Capture Supernovae from Core Collapse to Cooling

    SciTech Connect

    Huedepohl, L.; Mueller, B.; Janka, H.-T.; Marek, A.; Raffelt, G. G.

    2010-06-25

    An 8.8M{sub {center_dot}}electron-capture supernova was simulated in spherical symmetry consistently from collapse through explosion to essentially complete deleptonization of the forming neutron star. The evolution time ({approx}9 s) is short because high-density effects suppress our neutrino opacities. After a short phase of accretion-enhanced luminosities ({approx}200 ms), luminosity equipartition among all species becomes almost perfect and the spectra of {nu}{sub e} and {nu}{sub {mu},{tau}}very similar, ruling out the neutrino-driven wind as r-process site. We also discuss consequences for neutrino flavor oscillations.

  6. Precise convective cooling simulation of electronic equipment under various g-conditions

    NASA Astrophysics Data System (ADS)

    Adam, Johannes; Stuempel, Dieter; Rath, Michael

    1991-12-01

    Using the thermohydraulic code 'THEBES' a three dimensional flow analysis of a Spacelab rack under forced convection and a combined convective, conductive and radiative analysis of a closed electronic box under various g conditions are presented. The capabilities and features of THEBES are described. The motivation to extend the thermal analysis cycle for better treatment of fluid flow and solid to air heat transfer is discussed. It is proposed to include THEBES in a thermal analysis toolsat and present a concept for integration of THEBES with ESABASE.

  7. Resonance zones for electron interaction with plasma waves in the Earth's dipole magnetosphere. I. Evaluation for field-aligned chorus, hiss, and electromagnetic ion cyclotron waves

    NASA Astrophysics Data System (ADS)

    Ni, Binbin; Summers, Danny

    2010-04-01

    Wave-particle interactions are a key influence on radiation belt particle dynamics. Here electron cyclotron resonance with very-low-frequency chorus, extremely-low-frequency hiss, and electromagnetic ion cyclotron waves in the Earth's dipole magnetosphere is analyzed. In this first of two companion papers, it is assumed that wave propagation is field aligned. The aim of this investigation is to carry out a detailed examination of "resonance zones" in (L ,λ) space (where L denotes magnetic shell and λ the magnetic latitude). These zones are regions in which electron cyclotron resonance occurs for a given wave mode and waveband. Identification of resonance zones is a useful aid in the construction of realistic models of radiation belt electron dynamics, and is hence also useful in the interpretation of observational data.

  8. The recent and prospective developments of cooled IR FPAs for double application at Electron NRI

    NASA Astrophysics Data System (ADS)

    Arutunov, V. A.; Vasilyev, I. S.; Ivanov, V. G.; Prokofyev, A. E.

    2003-09-01

    The recent and prospective developments of monolithic silicon IR-Schottky-barrier staring focal plane arrays (IR SB FPAs), photodetector assembly, and digital thermal imaging cameras (TICs) at Electron National Research Institute (Electron NRI) are considered. Basic parameters for IR SB FPAs with 256x256 and 512x512 pixels, and TICs based on these arrays are presented. The problems emerged while proceeding from the developments of IR SB FPAs for the wavelength range from 3 μm to 5 μm to the developments of those ones for xLWIR range are indicated (an abrupt increase in the level of background architecture). Possibility for further improvement in basic parameters of IR SB FPAs are discussed (a decrease in threshold signal power down to 0.5-1.0"1013 W/element with an increase in quantum efficiency, a decrease in output noise and proceeding to Schottky barriers of degenerated semiconductor/silicon heterojunction, and implementation of these array parameters in photodetector assembly with improved thermal background shielding taking into consideration an optical structure of TIC for concrete application). It is concluded that relative simplicity of the technology and expected low cost of monolithic silicon IR SB FPAs with basic parameters compared with hybrid IR FPAs for the wavelength ranges from 3 μm to 5 μm and from 8 μm to 12 μm maintain large monolithic IR SB FPAs as a basis for developments of double application digital TICs in the Russian Federation.

  9. Experimental investigation of the ionospheric hysteresis effect on the threshold excitation level of the Stimulated Electromagnetic Emission (SEE) during heating at the second electron gyro-harmonic frequency

    NASA Astrophysics Data System (ADS)

    Samimi, A.; Scales, W.; Cruz, M.; Isham, B.; Bernhardt, P. A.

    2012-12-01

    Recent experimental observations of the stimulated electromagnetic emission (SEE) spectrum during heating at the second electron gyro-harmonic show structures ordered by ion gyro-frequency. The proposed generation mechanism considers parametric decay of a pump upper hybrid/electron Bernstein (UH/EB) wave into another UH/EB and a group of neutralized ion Bernstein waves. The presumption of the proposed mechanism is that the pump electromagnetic wave is converted into the UH/EB wave. This conversion process generates field aligned irregularity which exhibits hysteresis effect. The predicted ionospheric hysteresis effect is studied during the PARS 2012 at HAARP. The preliminary results are presented for the first time. Also, experimental study of the effects of 1) the transmitter beam angle and 2) the transmitter frequency offset relative to the second electron gyro-harmonic frequency on the ion gyro-harmonic structures in the SEE spectrum are provided. The aforementioned observations are compared to the predictions of the analytical model. Possible connection of the SEE spectral features and artificially generated ionospheric descending layer is also discussed

  10. Electromagnetic radiation from positive-energy bound electrons in the Coulomb field of a nucleus at rest in a strong uniform magnetic field

    SciTech Connect

    Arsenyev, S. A.; Koryagin, S. A.

    2012-06-15

    A classical analysis is presented of the electromagnetic radiation emitted by positive-energy electrons performing bound motion in the Coulomb field of a nucleus at rest in a strong uniform magnetic field. Bounded trajectories exist and span a wide range of velocity directions near the nucleus (compared to free trajectories with similar energies) when the electron Larmor radius is smaller than the distance at which the electron-nucleus Coulomb interaction energy is equal to the mechanical energy of an electron. The required conditions occur in magnetic white dwarf photospheres and have been achieved in experiments on production of antihydrogen. Under these conditions, the radiant power per unit volume emitted by positive-energy bound electrons is much higher than the analogous characteristic of bremsstrahlung (in particular, in thermal equilibrium) at frequencies that are below the electron cyclotron frequency but higher than the inverse transit time through the interaction region in a close collision in the absence of a magnetic field. The quantum energy discreteness of positive-energy bound states restricts the radiation from an ensemble of bound electrons (e.g., in thermal equilibrium) to nonoverlapping spectral lines, while continuum radiative transfer is dominated by linearly polarized bremsstrahlung.

  11. Stimulated electromagnetic emission and plasma line during pump wave frequency stepping near 4th electron gyroharmonic at HAARP

    NASA Astrophysics Data System (ADS)

    Grach, Savely; Sergeev, Evgeny; Shindin, Alexey; Mishin, Evgeny; Watkins, Brenton

    Concurrent observations of stimulated (secondary) electromagnetic emissions (SEE) and incoherent plasma line (PL) backscatter from the MUIR radar during HF pumping of the ionosphere by the HAARP heating facility (62.4(°) °N, 145.15(°) W, magnetic inclination α = 75.8^circ) with the pump wave (PW) frequency sweeps about the fourth electron gyroharmonic (4f_c) are presented. The PW frequency f0 was changed every 0.2 s in a 1-kHz step, i.e. with the rate of r_{f_0}=5 kHz/s. PW was transmitted at the magnetic zenith (MZ). Prior to sweeping, PW was transmitted continuously (CW) during 2 min at f_0 = 5730 kHz <4f_c to create the “preconditioned” ionosphere with small-scale magnetic field-aligned irregularities. During CW pumping, a typical SEE spectrum for f_0<4f_c, containing the prominent downshifted maxiμm (DM) shifted by Delta f_{DM} = f_{DM}-f_0approx-9 kHz, developed in 5-10 s after PW turn on. The PL echoes were observed during 2-3 s from the range dsim 220 km corresponding to the altitude slightly above PW reflection height. After sim5 s the PL echoes descended to dsim 210-212 km corresponding to the height h = d / (sinalpha) by sim 7 km below the height where f_0 = 4f_c. During frequency sweeps, two upshifted features appeared in the SEE spectrum for f_0> 4f_c, namely BUM_S and BUM_D. The former (stationary broad upshifted maxiμm) peaks at Delta f_{BUMs} approx f0 - nfc (d) + 15-20 kHz and is a typical SEE spectral feature. The latter, the dynamic BUM_D at smaller Delta f, is observed only at high pump powers (ERP=1.7 GW) and corresponds to artificial descending plasma layers created in the F-region ionosphere [1]. In the experiment in question, the BUM_D was present for f_0> f^*, where f^* was 5805-5815 kHz during stepping up and sim 10 kHz less for stepping down, and located 8-10 km below the background F-layer. The miniμm DM which indicated that f_0=4f_c=f_{uh} in the background ionospheric plasma, was sim 5760 kHz. The PL was observed only for f_0< f^* and mainly from altitudes h where f_0 <4f_c. The height h decreased with increasing f_0 in accordance with the altitude dependence 4f_c(h), the difference Delta f_g = f_0 - 4f_c was kept constant during either sweeping up [-(4-8 kHz)] or sweeping down [-(18-22 kHz)]. This corresponds to the difference between the altitude where f_0=4f_c and the PL generation altitude by Delta h sim 1.5-3 km and 7-8 km, respectively. During stepping up, the PL was observed also from the ranges where f_0 > 4f_c. In this case we obtained Delta f_g sim 8-13 kHz corresponding to Delta h sim - 4 km. The PL has never been observed for f_0>f^*$. \\ 1. Sergeev E., Grach S., et al. //Phys. Rev. Lett., 110 (2013), 065002.

  12. Trapping of high-energy electrons into regime of surfatron acceleration by electromagnetic waves in space plasma

    SciTech Connect

    Erokhin, A. N.; Erokhin, N. S.; Milant'ev, V. P.

    2012-05-15

    The phenomenon of trapping of weakly relativistic charged particles (with kinetic energies on the order of mc{sup 2}) into a regime of surfatron acceleration by an electromagnetic wave that propagates in plasma across a weak external magnetic field has been studied using nonlinear numerical calculations based on a solution of the relativistic equations of motion. Analysis showed that, for the wave amplitude above a certain threshold value and the initial wave phase outside the interval favorable for the surfing regime, the trajectory of a charged particle initially corresponds to its cyclotron rotation in the external magnetic field. For the initial particle energies studied, the period of this rotation is relatively short. After a certain number (from several dozen to several thousand and above) of periods of rotation, the wave phase takes a value that is favorable for trapping of the charged particle on its trajectory by the electromagnetic wave, provided the Cherenkov resonance conditions are satisfied. As a result, the wave traps the charged particle and imparts it an ultrarelativistic acceleration. In momentum space, the region of trapping into the regime of surfing on an electromagnetic wave turns out to be rather large.

  13. Anomalous electron cooling observed by the eiscat within the dusty nightside auroral dynamo layer

    NASA Astrophysics Data System (ADS)

    Timofeev, Evgeny; Kangas, Jorma; Vallinkoski, Matti; Shalimov, Sergey

    In the present study we analyze parameters of the lower ionosphere, measured by the EISCAT radar facility at the zenith of Tromsø auroral observatory during the ERRRIS campaign. Data used consists of 20 different nights of observations and includes approximately 2000 measurements. At that 75% and 25% of the data corresponds to measured ionospheric electric field that is below and above the threshold of the Farley-Buneman instability (which is 15-20 mV/m), respectively. In the first part of our analysis the height profiles of the electron and ion temperature difference (Te-Ti) (including standard deviation, STD) for both, small and large electric fields were calculated using the superimposed epoch method. It was shown that: 1) for the large electric fields the profile (Te-Ti) with Te>Ti takes the maximum (60-70 K) at 115 km in agreement with the standard conception; 2) for the small electric fields the thermal anomaly was revealed when Teelectron temperature can decrease whilst the ion temperature increases.

  14. ELECTROMAGNETIC PUMP

    DOEpatents

    Pulley, O.O.

    1954-08-17

    This patent reiates to electromagnetic pumps for electricity-conducting fluids and, in particular, describes several modifications for a linear conduction type electromagnetic interaction pump. The invention resides in passing the return conductor for the current traversing the fiuid in the duct back through the gap in the iron circuit of the pump. Both the maximum allowable pressure and the efficiency of a linear conduction electromagnetic pump are increased by incorporation of the present invention.

  15. Electromagnetic fields of a relativistic electron avalanche with special attention to the origin of lightning signatures known as narrow bipolar pulses

    NASA Astrophysics Data System (ADS)

    Cooray, Vernon; Cooray, Gerald; Marshall, Thomas; Arabshahi, Shahab; Dwyer, Joseph; Rassoul, Hamid

    2014-11-01

    In the present study, electromagnetic fields of accelerating charges were utilized to evaluate the electromagnetic fields generated by a relativistic electron avalanche. In the analysis it is assumed that all the electrons in the avalanche are moving with the same speed. In other words, the growth or the decay of the number of electrons takes place only at the head of the avalanche. It is shown that the radiation is emanating only from the head of the avalanche where electrons are being accelerated. It is also shown that an analytical expression for the radiation field of the avalanche at any distance can be written directly in terms of the e-folding length of the avalanche. This model of the avalanche was utilized to test the idea whether the source of the lightning signatures known as narrow bipolar pulses could be relativistic avalanches. The idea was tested by using the simultaneously measured electric fields of narrow bipolar pulses at two distances, one measured far away from the source and the other in the near vicinity. The avalanche parameters were extracted from the distant field and they are used to evaluate the close field. The results show that the source of the NBP can be modeled either as a single or a multiple burst of relativistic avalanches with speed of avalanches in the range of 2-3 × 108 m/s. The multiple avalanche model agrees better with the experimental data in that it can also generate the correct signature of the time derivatives and the HF and VHF radiation bursts of NBP.

  16. Noise Temperature and IF Bandwidth of a 530 GHz Heterodyne Receiver Employing a Diffusion-Cooled Superconducting Hot-Electron Mixer

    NASA Technical Reports Server (NTRS)

    Skalare, A.; McGrath, W. R.; Bumble, B.; LeDuc, H. G.; Burke, P. J.; Verheijen, A. A.; Prober, D. E.

    1995-01-01

    We report on the first heterodyne measurements with a diffusion-cooled hot-electron bolometer mixer in the submillimeter wave band, using a waveguide mixer cooled to 2.2 K. The best receiver noise temperature at a local oscillator frequency of 533 GHz and an intermediate frequency of 1.4 GHz was 650 K (double sideband). The 3 dB IF roll-off frequency was around 1.7 to 1.9 GHz, with a weak dependence on the device bias conditions.

  17. Electromagnetic Attraction.

    ERIC Educational Resources Information Center

    Milson, James L.

    1990-01-01

    Three activities involving electromagnetism are presented. Discussed are investigations involving the construction of an electromagnet, the effect of the number of turns of wire in the magnet, and the effect of the number of batteries in the circuit. Extension activities are suggested. (CW)

  18. Electromagnetic direct implicit PIC simulation

    SciTech Connect

    Langdon, A.B.

    1983-03-29

    Interesting modelling of intense electron flow has been done with implicit particle-in-cell simulation codes. In this report, the direct implicit PIC simulation approach is applied to simulations that include full electromagnetic fields. The resulting algorithm offers advantages relative to moment implicit electromagnetic algorithms and may help in our quest for robust and simpler implicit codes.

  19. Electromagnetic acoustic transduction using a pulsed electromagnet

    NASA Astrophysics Data System (ADS)

    Palmer, S. B.; Hernandez-Valle, J. F.; Dixon, S.

    2009-03-01

    Some early designs of Electromagnetic Acoustic Transducers (EMATs) used electromagnets to provide the strong magnetic field required for the transducer to operate. The advent of a new generation of permanent magnets such as NdFeB, with magnetic fields approaching 1T, meant that many EMAT designs switched over to using these small, compact and relatively inexpensive magnets. Typically, most modern EMATs make use of permanent magnets since they can exert high magnetic fields with compact structures. There are certain limitations when using permanent magnets, and their low Curie points of between 80-150C limit their practicality for high temperature testing without using water cooled transducers. In this work we have employed a pulsed electromagnet to provide the magnetic field. Pulsing the magnet dramatically reduces the average power required, keeping the supply more compact and less complex. It has the added advantage on ferritic steels, of resulting in much larger amplitude ultrasonic signals and improved signal to noise when compared with EMATs which use the strongest permanent magnets available.

  20. Comparison of Electromagnetic Field Signatures in Regions of Dispersive and Quasi-Static Electron Precipitation During the GREECE Sounding Rocket Flight

    NASA Astrophysics Data System (ADS)

    Bonnell, J. W.; Carruth, N.; Slagle, A.; Samara, M.; Michell, R.; Grubbs, G. A., II; Ogasawara, K.; Jahn, J. M.

    2014-12-01

    The NASA GREECE (Ground-to-Rocket Electrodynamics-Electrons Corelative Experiment) sounding rocket flew through two regions of electron precipitation associated with dynamic visual aurora on 03 Mar 2014. The first weaker precipitation region showed evidence of energy-time dispersion in the softer and weaker electron precipitation, while the later precipitation region showed evidence of quasi-static monoenergetic peaks in the somewhat harder precipitating electron spectra.Comparisons between the observed electromagnetic (EM) field (quasi-DC) and wave properties (0.1-8 kHz) in the two precipitation regions will be shown, including: measured plasma density; estimated spectral densities of E and B; derived polarization, cross-spectral phase and coherence, and parallel Poynting flux.The measured EM field parameters will be compared against extant models of static and dynamic coupling of the high- and low-altitude ionosphere in regions of active small-scale auroral features and precipitation to discriminate between viable models of the two sorts of auroral precipitation and acceleration.

  1. Assessment of Electromagnetic Interference with Active Cardiovascular Implantable Electronic Devices (CIEDs) Caused by the Qi A13 Design Wireless Charging Board

    PubMed Central

    Seckler, Tobias; Jagielski, Kai; Stunder, Dominik

    2015-01-01

    Electromagnetic interference is a concern for people wearing cardiovascular implantable electronic devices (CIEDs). The aim of this study was to assess the electromagnetic compatibility between CIEDs and the magnetic field of a common wireless charging technology. To do so the voltage induced in CIEDs by Qi A13 design magnetic fields were measured and compared with the performance limits set by ISO 14117. In order to carry this out a measuring circuit was developed which can be connected with unipolar or bipolar pacemaker leads. The measuring system was positioned at the four most common implantation sites in a torso phantom filled with physiological saline solution. The phantom was exposed by using Helmholtz coils from 5 µT to 27 µT with 111 kHz sine-bursts or by using a Qi A13 design wireless charging board (Qi-A13-Board) in two operating modes “power transfer” and “pinging”. With the Helmholtz coils the lowest magnetic flux density at which the performance limit was exceeded is 11 µT. With the Qi-A13-Board in power transfer mode 10.8% and in pinging mode 45.7% (2.2% at 10 cm distance) of the performance limit were reached at maximum. In neither of the scrutinized cases, did the voltage induced by the Qi-A13-Board exceed the performance limits. PMID:26024360

  2. Electromagnetic fasteners

    DOEpatents

    Crane, Randolph W.; Marts, Donna J.

    1994-11-01

    An electromagnetic fastener for manipulating objects in space uses the matic attraction of various metals. An end effector is attached to a robotic manipulating system having an electromagnet such that when current is supplied to the electromagnet, the object is drawn and affixed to the end effector, and when the current is withheld, the object is released. The object to be manipulated includes a multiplicity of ferromagnetic patches at various locations to provide multiple areas for the effector on the manipulator to become affixed to the object. The ferromagnetic patches are sized relative to the object's geometry and mass.

  3. Electromagnetic fasteners

    DOEpatents

    Crane, Randolph W.; Marts, Donna J.

    1994-01-01

    An electromagnetic fastener for manipulating objects in space uses the matic attraction of various metals. An end effector is attached to a robotic manipulating system having an electromagnet such that when current is supplied to the electromagnet, the object is drawn and affixed to the end effector, and when the current is withheld, the object is released. The object to be manipulated includes a multiplicity of ferromagnetic patches at various locations to provide multiple areas for the effector on the manipulator to become affixed to the object. The ferromagnetic patches are sized relative to the object's geometry and mass.

  4. Analysis of the dependence of surfatron acceleration of electrons by an electromagnetic wave in space plasma on the particle momentum along the wave front

    NASA Astrophysics Data System (ADS)

    Erokhin, A. N.; Zol'nikova, N. N.; Erokhin, N. S.

    2016-01-01

    Based on the numerical solution of the nonlinear nonstationary second-order equation for the wave phase on the particle trajectory, the dynamics of surfatron acceleration of electrons by an electromagnetic wave propagating across the external magnetic field in space plasma is analyzed as a function of the electron momentum along the wave front. Numerical calculations show that, for strongly relativistic initial values of the electron momentum component along the wave front g y (0) (the other parameters of the problem being the same), electrons are trapped into the regime of ultrarelativistic surfatron acceleration within a certain interval of the initial wave phase Ψ(0) on the particle trajectory. It is assumed in the calculations that |Ψ(0)| ≤ π. For strongly relativistic values of g y (0), electrons are immediately trapped by the wave for 19% of the initial values of the phase Ψ(0) (favorable phases). For the rest of the values of Ψ(0), trapping does not occur even at long times. This circumstance substantially simplifies estimations of the wave damping due to particle acceleration in subsequent calculations. The dynamics of the relativistic factor and the components of the electron velocity and momentum under surfatron acceleration is also analyzed. The obtained results are of interest for the development of modern concepts of possible mechanisms of generation of ultrarelativistic particle fluxes in relatively calm space plasma, as well as for correct interpretation of observational data on the fluxes of such particles and explanation of possible reasons for the deviation of ultrarelativistic particle spectra detected in the heliosphere from the standard power-law scalings and the relation of these variations to space weather and large-scale atmospheric processes similar to tropical cyclones.

  5. Stochastic cooling

    SciTech Connect

    Bisognano, J.; Leemann, C.

    1982-03-01

    Stochastic cooling is the damping of betatron oscillations and momentum spread of a particle beam by a feedback system. In its simplest form, a pickup electrode detects the transverse positions or momenta of particles in a storage ring, and the signal produced is amplified and applied downstream to a kicker. The time delay of the cable and electronics is designed to match the transit time of particles along the arc of the storage ring between the pickup and kicker so that an individual particle receives the amplified version of the signal it produced at the pick-up. If there were only a single particle in the ring, it is obvious that betatron oscillations and momentum offset could be damped. However, in addition to its own signal, a particle receives signals from other beam particles. In the limit of an infinite number of particles, no damping could be achieved; we have Liouville's theorem with constant density of the phase space fluid. For a finite, albeit large number of particles, there remains a residue of the single particle damping which is of practical use in accumulating low phase space density beams of particles such as antiprotons. It was the realization of this fact that led to the invention of stochastic cooling by S. van der Meer in 1968. Since its conception, stochastic cooling has been the subject of much theoretical and experimental work. The earliest experiments were performed at the ISR in 1974, with the subsequent ICE studies firmly establishing the stochastic cooling technique. This work directly led to the design and construction of the Antiproton Accumulator at CERN and the beginnings of p anti p colliding beam physics at the SPS. Experiments in stochastic cooling have been performed at Fermilab in collaboration with LBL, and a design is currently under development for a anti p accumulator for the Tevatron.

  6. Information Security due to Electromagnetic Environments

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Hidenori; Seto, Shinji

    Generally, active electronic devices emit slightly unintentional electromagnetic noise. From long ago, electromagnetic emission levels have been regulated from the aspect of electromagnetic compatibility (EMC). Also, it has been known the electromagnetic emissions have been generated from the ON/OFF of signals in the device. Recently, it becomes a topic of conversation on the information security that the ON/OFF on a desired signal in the device can be reproduced or guessed by receiving the electromagnetic emission. For an example, a display image on a personal computer (PC) can be reconstructed by receiving and analyzing the electromagnetic emission. In sum, this fact makes known information leakage due to electromagnetic emission. “TEMPEST" that has been known as a code name originated in the U. S. Department of Defense is to prevent the information leakage caused by electromagnetic emissions. This paper reports the brief summary of the information security due to electromagnetic emissions from information technology equipments.

  7. Nuclear Electromagnetic Pulse Review

    NASA Astrophysics Data System (ADS)

    Dinallo, Michael

    2011-04-01

    Electromagnetic Pulse (EMP) from nuclear detonations have been observed for well over half a century. Beginning in the mid-to-late 1950s, the physics and modeling of EMP has been researched and will continue into the foreseeable future. The EMP environment propagates hundreds of miles from its origins and causes interference for all types of electronic instrumentation. This includes military, municipal and industry based electronic infrastructures such as power generation and distribution, command and control systems, systems used in financial and emergency services, electronic monitoring and communications networks, to mention some key infrastructure elements. Research into EMP has included originating physics, propagation and electromagnetic field coupling analyses and measurement-sensor development. Several methods for calculating EMP induced transient interference (voltage and current induction) will be briefly discussed and protection techniques reviewed. These methods can be mathematically simple or involve challenging boundary value solution techniques. A few illustrative calculations will demonstrate the concern for electronic system operability. Analyses such as the Wunsch-Bell model for electronic upset or damage, and the Singularity Expansion Method (SEM) put forth by Dr. Carl Baum, will facilitate the concern for EMP effects. The SEM determines the voltages and currents induced from transient electromagnetic fields in terms of natural modes of various types of electronic platforms (aerospace vehicles or land-based assets - fixed or mobile). Full-scale facility and laboratory simulation and response measurement approaches will be discussed. The talk will conclude with a discussion of some present research activities.

  8. Electromagnetic Accelerator

    NASA Astrophysics Data System (ADS)

    Land, Jared

    2012-03-01

    The objective of this senior physics student research project was to design a functional electromagnetic accelerator (i.e. railgun), with considerations for size, portability, modularity, and weight. This has been accomplished through practical design application of electromagnetic principles and streamlined construction to study effects of various rail geometries/bore profiles, and projectile design. The railgun has been tested and its efficiency has been studied.

  9. Resonance zones for electron interaction with plasma waves in the Earth's dipole magnetosphere. II. Evaluation for oblique chorus, hiss, electromagnetic ion cyclotron waves, and magnetosonic waves

    NASA Astrophysics Data System (ADS)

    Ni, Binbin; Summers, Danny

    2010-04-01

    Resonance zones in the Earth's dipole magnetosphere are determined for electron cyclotron resonance with obliquely propagating very-low-frequency chorus, extremely-low-frequency hiss, electromagnetic ion cyclotron, and magnetosonic waves. The resonance zones, which are presented in (L ,λ) space, where L is magnetic shell and λ is magnetic latitude, depend on the assumed particle density distributions inside and outside the plasmasphere, the specified wave bands, and the electron kinetic energy. This work is a companion paper of Ni and Summers [Phys. Plasmas 17, 042902 (2010)], which considers strictly field-aligned wave propagation. Inclusion of the wave normal angle parameter adds an extra degree of freedom to the calculations, and emphasizes the need for global observational data on the wave spectral properties. Comparison of resonance zones with global wave distributions is a useful aid in the modeling of radiation belt electron dynamics. Resonance zones are also of potential use in the interpretation of observational data on particles and waves at given points in space.

  10. Electromagnetic effects on geodesic acoustic modes

    NASA Astrophysics Data System (ADS)

    Bashir, M. F.; Smolyakov, A. I.; Elfimov, A. G.; Melnikov, A. V.; Murtaza, G.

    2014-08-01

    By using the full electromagnetic drift kinetic equations for electrons and ions, the general dispersion relation for geodesic acoustic modes (GAMs) is derived incorporating the electromagnetic effects. It is shown that m = 1 harmonic of the GAM mode has a finite electromagnetic component. The electromagnetic corrections appear for finite values of the radial wave numbers and modify the GAM frequency. The effects of plasma pressure βe, the safety factor q, and the temperature ratio τ on GAM dispersion are analyzed.

  11. Possibility of studying the electromagnetic properties of neutral pions in experiments in colliding electron-positron beams

    SciTech Connect

    Bel'kov, A.A.; Kuraev, E.A.; Pervushin, V.N.

    1984-12-01

    We consider the possibility of experimentally studying the low energy electromagnetic parameters of neutral pions in colliding e/sup +/e/sup -/ beams. The cross sections for the reactions e/sup +/e/sup -/..--> pi../sup 0/..pi../sup 0/..gamma.., e/sup +/e/sup -/..-->..e/sup +/e/sup -/..pi../sup 0/..pi../sup 0/, and e/sup +/e/sup -/..--> pi../sup 0/..pi../sup 0/ are estimated in the theory with broken chiral symmetry. The calculations show that these processes can be studied in existing e/sup +/e/sup -/ beams. Such experiments give model-independent information on the amplitude of the Compton effect on the neutral pion (..gamma gamma --> pi../sup 0/..pi../sup 0/) in the physical region of the ..pi pi.. interaction m/sup 2//sub pipi/>4m/sup 2//sub ..pi../. In this region the amplitude of the process ..gamma gamma --> pi../sup 0/..pi../sup 0/ is mainly determined by a sub-threshold anomaly related to pion rescattering.

  12. Refrigerant directly cooled capacitors

    DOEpatents

    Hsu, John S.; Seiber, Larry E.; Marlino, Laura D.; Ayers, Curtis W.

    2007-09-11

    The invention is a direct contact refrigerant cooling system using a refrigerant floating loop having a refrigerant and refrigeration devices. The cooling system has at least one hermetic container disposed in the refrigerant floating loop. The hermetic container has at least one electronic component selected from the group consisting of capacitors, power electronic switches and gating signal module. The refrigerant is in direct contact with the electronic component.

  13. Self-consistent Model of Magnetospheric Ring Current and Propagating Electromagnetic Ion Cyclotron Waves. 2. Wave Induced Ring Current Precipitation and Thermal Electron Heating

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Gamayunov, K. V.; Gallagher, D. L.; Kozyra, J. U.; Liemohn, M. W.

    2007-01-01

    This paper continues presentation and discussion of the results from our new global self-consistent theoretical model of interacting ring current ions and propagating electromagnetic ion cyclotron waves [Khazanov et al., 2006]. To study the effects of electromagnetic ion cyclotron wave propagation and refraction on the wave induced ring current precipitation and heating of the thermal plasmaspheric electrons, we simulate the May 1998 storm. The main findings after a simulation can be summarized as follows. Firstly, the wave induced ring current precipitation exhibits quite a lot of fine structure, and is highly organized by location of the plasmapause gradient. The strongest fluxes of about 4 x 10(exp 6) (cm(raised dot) s(raised dot) sr(raised dot) (sup -1)) are observed during the maill and early recovery phases of the storm. The very interesting and probably more important finding is that in a number of cases the most intense precipitating fluxes are not connected to the most intense waves in simple manner. The characteristics of the wave power spectral density distribution over the wave normal angle are extremely crucial for the effectiveness of the ring current ion scattering. Secondly, comparison of the global proton precipitating patterns with the results from RAM [Kozyra et al., 1997a] reveals that although we observe a qualitative agreement between the localizations of the wave induced precipitations in the models, there is no quantitative agreement between the magnitudes of the fluxes. The quantitative differences are mainly due to a qualitative difference between the characteristics of the wave power spectral density distributions over the wave normal angle in RAM and in our model. Thirdly, the heat fluxes to plasmaspheric electrons caused by Landau resonate energy absorption from electromagnetic ion cyclotron waves are observed in the postnoon-premidnight MLT sector, and can reach the magnitude of 10(exp 11) eV/(cm(sup 2)(raised dot)s). The Coulomb energy degradation of the RC H(+) and O(+) ions maximizes at about 10(exp 11) (eV/(cm(sup 2) (raised dot) s), and typically leads to electron energy deposition rates of about 2(raised dot) 10(exp 10) (eV/(cm(sup 2)(raised dot)s) which are observed during two periods; 32-48 hours, and 76-86 hours after 1 May, 0000 UT. The theoretically derived spatial structure of the thermal electron heating caused by interaction of the ring current with the plasmasphere is strongly supported by concurrent and conjugate plasma measurements from the plasmasphere, ring current, and topside ionosphere [Gurgiolo et al., 2005]. Finally, the wave induced intense electron heating has a structure of the spot-like patches along the most enhanced density gradients in the plasmasphere boundary layer and can be a possible driver to the observed but still not explained small-scale structures of enhanced emissions in the stable auroral red arcs.

  14. Electromagnetic particle simulation codes

    NASA Technical Reports Server (NTRS)

    Pritchett, P. L.

    1985-01-01

    Electromagnetic particle simulations solve the full set of Maxwell's equations. They thus include the effects of self-consistent electric and magnetic fields, magnetic induction, and electromagnetic radiation. The algorithms for an electromagnetic code which works directly with the electric and magnetic fields are described. The fields and current are separated into transverse and longitudinal components. The transverse E and B fields are integrated in time using a leapfrog scheme applied to the Fourier components. The particle pushing is performed via the relativistic Lorentz force equation for the particle momentum. As an example, simulation results are presented for the electron cyclotron maser instability which illustrate the importance of relativistic effects on the wave-particle resonance condition and on wave dispersion.

  15. Aircraft electromagnetic compatibility

    NASA Technical Reports Server (NTRS)

    Clarke, Clifton A.; Larsen, William E.

    1987-01-01

    Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting.

  16. Cooling for a rotating anode X-ray tube

    DOEpatents

    Smither, Robert K. (Hinsdale, IL)

    1998-01-01

    A method and apparatus for cooling a rotating anode X-ray tube. An electromagnetic motor is provided to rotate an X-ray anode with cooling passages in the anode. These cooling passages are coupled to a cooling structure located adjacent the electromagnetic motor. A liquid metal fills the passages of the cooling structure and electrical power is provided to the motor to rotate the anode and generate a rotating magnetic field which moves the liquid metal through the cooling passages and cooling structure.

  17. Ab initio study on the electronic states and laser cooling of AlCl and AlBr

    NASA Astrophysics Data System (ADS)

    Rong, Yang; Bin, Tang; Tao, Gao

    2016-04-01

    We investigate whether AlCl and AlBr are promising candidates for laser cooling. We report new ab initio calculations on the ground state X1Σ+ and two low-lying states (A1Π and a3Π) of AlCl and AlBr. The calculated spectroscopic constants show good agreement with available theoretical and experimental results. We also obtain the permanent dipole moments (PDMs) curve at multi-reference configuration interaction (MRCI) level of theory. The transition properties of A1Π and a3Π states are predicted, including the transition dipole moments (TDMs), Franck–Condon factors (FCFs), radiative times and radiative width. The calculated radiative lifetimes are of the order of a nanosecond, implying that they are sufficiently short for rapid laser cooling. Both AlCl and AlBr have highly diagonally distributed FCFs which are crucial requirement for molecular laser cooling. The results demonstrate the feasibility of laser cooling AlCl and AlBr, and we propose laser cooling schemes for AlCl and AlBr.

  18. Electromagnetic shocks on the optical cycle of ultrashort pulses in triple-resonance Lorentz dielectric media with subfemtosecond nonlinear electronic Debye relaxation.

    PubMed

    Gilles, L; Moloney, J V; Vázquez, L

    1999-07-01

    The dynamical evolution of an intense ultrashort sub-10-fs two-cycle optical pulse is considered as it propagates through a transparent third-order dielectric medium characterized by three resonance lines and a finite sub-fs relaxation time of the electronic nonlinearity. Numerical integration of the full Maxwell's equations incorporating triple-resonance Lorentz linear dispersion and Debye nonlinear dispersion, for a linearly polarized electromagnetic pulse centered at lambda(0)=1.24 microm in the normal dispersion region near the zero dispersion wavelength, shows the formation of shocks occurring on the optical cycle due to the generation of optical harmonics. The finite relaxation time of the nonlinear electronic response (sub-fs time scale) (i) slows down the steepening rate of the optical cycle; (ii) does not limit the generation of strongly phase matched optical harmonics, and consequently the development of infinitely sharp edges on the optical cycle producing its breaking when linear dispersion is not included; (iii) reduces the production of phase matched harmonics and consequently the sharpening of the jumps when dispersion is present, compared to the case of an instantaneous nonlinear response; and (iv) reduces the harmonic spectrum spreading and modulation at later times on the appearance of self-steepening of the electric field envelope. PMID:11969852

  19. Electromagnetic Propulsion

    NASA Technical Reports Server (NTRS)

    Schafer, Charles

    2000-01-01

    The design and development of an Electromagnetic Propulsion is discussed. Specific Electromagnetic Propulsion Topics discussed include: (1) Technology for Pulse Inductive Thruster (PIT), to design, develop, and test of a multirepetition rate pulsed inductive thruster, Solid-State Switch Technology, and Pulse Driver Network and Architecture; (2) Flight Weight Magnet Survey, to determine/develop light weight high performance magnetic materials for potential application Advanced Space Flight Systems as these systems develop; and (3) Magnetic Flux Compression, to enable rapid/robust/reliable omni-planetary space transportation within realistic development and operational costs constraints.

  20. Research Investigation Directed Toward Extending the Useful Range of the Electromagnetic Spectrum. [atomic spectra and electronic structure of alkali metals

    NASA Technical Reports Server (NTRS)

    Hartmann, S. R.; Happer, W.

    1974-01-01

    The report discusses completed and proposed research in atomic and molecular physics conducted at the Columbia Radiation Laboratory from July 1972 to June 1973. Central topics described include the atomic spectra and electronic structure of alkali metals and helium, molecular microwave spectroscopy, the resonance physics of photon echoes in some solid state systems (including Raman echoes, superradiance, and two photon absorption), and liquid helium superfluidity.

  1. High-Resolution Measurements of Electron Temperature, Density, and Width Profiles of 234 Coronal Loops in the Non-Equilibrium Cooling Phase

    NASA Astrophysics Data System (ADS)

    Nightingale, R. W.; Aschwanden, M. J.

    2008-05-01

    We measure the profiles of the electron temperature Te(s), the electron density ne(s), and loop widths w(s) of 234 coronal loops from triple-filter TRACE data. We model also the loop geometry with a semi-circular model in order to measure the unprojected full loop length L and the inclination angle θ of the loop plane to the vertical, which are both required to apply loop scaling laws and hydrodynamic models. The statistics of the measured loop parameters are: electron temperatures Te=1.18±0.30 MK, electron densities ne=10(9.0± 0.2) cm-3, loop widths w=1.44±0.33 Mm, loop lengths L=56± 47 Mm, fraction of detected loop lengths Ldet/L =0.67±0.23, and loop inclination angles |θ|=22° ± 18°. From these parameters we determine the average overpressure of these loops with respect to the equilibrium RTV law, q=p/pRTV and find that 86% of the loops exhibit an overpressure (up to q < 30), 9% an underpressure, and only about 5% are consistent with RTV. We interpret the observed overpressure as a natural consequence of the non-equilibrium cooling phase. Applying a non-equilibrium scaling law we predict that the loops were heated to soft X-ray temperatures up to Te < 15 MK prior to their cooling to EUV wavelengths. For the loop lifetimes we find an approximate scaling of τlife ≍ 10 (L/10 Mm)2 min, with a median lifetime of 7 hours for our sample of TRACE loops. This study postulates a paradigm shift from equilibrium models to non-equilibrium models in the loop cooling phase, which is dominantly observed in EUV wavelengths. This work was supported in part by NASA under the TRACE contract NAS5-38099.

  2. Fundamental studies in cryogenic cooling of power electronics. Interim report, 1 September 1993-1 August 1994

    SciTech Connect

    Chow, L.C.; Sehmbey, M.S.; Hahm, O.J.; Chui, C.J.

    1994-09-01

    This study details the results from experiments conducted to study the heat transfer characteristics during liquid nitrogen spray cooling and pool boiling from a heater array. Four different nozzles at various pressures were used to study the variation in spray cooling heat transfer at liquid nitrogen temperature. Effect of nozzle and flow rate on the critical heat flux and the heat transfer coefficient are presented. This study also provides empirical correlations for the spray cooling characteristics. The critical heat flux and the heat transfer coefficient have been correlated using non-dimensional numbers. The study also shows the importance of surface roughness for spray cooling with liquid nitrogen. The rougher surfaces were shown to have significantly higher heat transfer rates and similar critical heat fluxes occurring at lower temperatures. The results from experiments conducted to study the pool boiling heat transfer from a vertical array with flush mounted heat sources are also presented. The lower heaters were found to enhance the heat transfer from the upper heaters due to bubble pumped convection.

  3. 3D printed electromagnetic transmission and electronic structures fabricated on a single platform using advanced process integration techniques

    NASA Astrophysics Data System (ADS)

    Deffenbaugh, Paul Issac

    3D printing has garnered immense attention from many fields including in-office rapid prototyping of mechanical parts, outer-space satellite replication, garage functional firearm manufacture, and NASA rocket engine component fabrication. 3D printing allows increased design flexibility in the fabrication of electronics, microwave circuits and wireless antennas and has reached a level of maturity which allows functional parts to be printed. Much more work is necessary in order to perfect the processes of 3D printed electronics especially in the area of automation. Chapter 1 shows several finished prototypes of 3D printed electronics as well as newly developed techniques in fabrication. Little is known about the RF and microwave properties and applications of the standard materials which have been developed for 3D printing. Measurement of a wide variety of materials over a broad spectrum of frequencies up to 10 GHz using a variety of well-established measurement methods is performed throughout chapter 2. Several types of high frequency RF transmission lines are fabricated and valuable model-matched data is gathered and provided in chapter 3 for future designers' use. Of particular note is a fully 3D printed stripline which was automatically fabricated in one process on one machine. Some core advantages of 3D printing RF/microwave components include rapid manufacturing of complex, dimensionally sensitive circuits (such as antennas and filters which are often iteratively tuned) and the ability to create new devices that cannot be made using standard fabrication techniques. Chapter 4 describes an exemplary fully 3D printed curved inverted-F antenna.

  4. Electromagnetic Survey

    USGS hydrologist conducts a broadband electromagnetic survey in New Orleans, Louisiana. The survey was one of several geophysical methods used during USGS applied research on the utility of the multi-channel analysis of surface waves (MASW) seismic method for non-invasive assessment of earthen levee...

  5. Electromagnetic Survey

    A USGS hydrologist conducts a near-surface electromagnetic induction survey to characterize the shallow earth. The survey was conducted as part of an applied research effort by the USGS Office of Groundwater Branch of Geophysics at Camp Rell, Connecticut, in 2008....

  6. Heat bath algorithmic cooling using electron-nuclear spin ensemble in the solid state: characterization of the open quantum system control

    NASA Astrophysics Data System (ADS)

    Park, Kyungdeock; Darabad, Robabeh; Feng, Guanru; Labruyere, Stephane; Baugh, Jonathan; Laflamme, Raymond

    2015-03-01

    The ability to perform multiple rounds of Quantum Error Correction (QEC) is an essential task for scalable quantum information processing, but experimental realizations of it are still in their infancy. Key requirements for QEC are high control fidelity and the ability to extract entropy from ancilla qubits. Nuclear Magnetic Resonance (NMR) quantum processors have demonstrated high control fidelity with up to 12 qubits. A remaining challenge is to prepare nearly pure ancilla qubits to enable QEC. Heat Bath Algorithmic Cooling (HBAC) is an efficient tool for extracting entropy from qubits that interact with a heat bath, allowing cooling below the bath temperature. For implementing HBAC with spins, a hyperfine coupled electron-nuclear system in a single crystal is more advantageous than conventional NMR systems since the electron, with higher polarization and faster relaxation, can act as a heat bath. We characterize 3 and 5 qubit spin systems in gamma-irradiated malonic acid and present simulation and experimental results of HBAC to benchmark our quantum control. Two control schemes are compared: electron nuclear double resonance and indirect control of nuclei via the anisotropic hyperfine interaction.

  7. Electromagnetic radiation mixer based on electron heating in resistive state of superconductive Nb and YBaCuO films

    NASA Astrophysics Data System (ADS)

    Gershenzon, E. M.; Gol'Tsman, G. N.; Gusev, Y. P.; Elant'ev, A. I.; Semenov, A. D.

    1991-03-01

    A theory of an electron-heating mixer which makes it possible to calculate all the characteristics of the device is developed. It is shown that positive conversion gain is possible for such a mixer in the millimeter to near-infrared wavelength range. The dynamic range and the optimum heterodyne power can be selected from a very wide interval by varying the mixing element volume. Measurements made for Nb within the frequency range of 120-750 GHz confirm the theory. The conversion loss obtained at T = 1.6 K and normalized to the element reaches 0.3 dB in the intermediate frequency band of 40 MHz; the possible noise temperature is 50 K. The estimation of noise temperature and output band for YBaCuO at T = 77 yields 200 K and more than 10 GHz, respectively.

  8. Electron impact cross-sections and cooling rates for methane. [in thermal balance of electrons in atmospheres and ionospheres of planets and satellites in outer solar system

    NASA Technical Reports Server (NTRS)

    Gan, L.; Cravens, T. E.

    1992-01-01

    Energy transfer between electrons and methane gas by collisional processes plays an important role in the thermal balance of electrons in the atmospheres and ionospheres of planets and satellites in the outer solar system. The literature is reviewed for electron impact cross-sections for methane in this paper. Energy transfer rates are calculated for elastic and inelastic processes using a Maxwellian electron distribution. Vibrational, rotational, and electronic excitation and ionization are included. Results are presented for a wide range of electron temperatures and neutral temperatures.

  9. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Stratified solutions for cooling of flashlamp-pumped lasers

    NASA Astrophysics Data System (ADS)

    Pashinin, Pavel P.; Semin, V. N.; Sukhodol'skiĭ, A. T.

    1988-04-01

    A study was made of a dynamic light-induced stratification phase transition in an aqueous solution of butyl cellosolve containing an admixture in the form of a dye absorbing in the ultraviolet part of the spectrum. Thermocapillary "expulsion" of the disperse phase containing butyl cellosolve occurred in the direction from the cell wall into the interior of the solution. This effect could be used in systems for cooling lasers in order to increase their service life.

  10. Prediction of Elastic Modulus + Anisotropy Using X-Ray and Electron Backscattered Diffraction Texture Quantification and Ultrasonic (Electromagnetic Acoustic Transducer) Measurements in Aluminum Sheets

    NASA Astrophysics Data System (ADS)

    Davis, C. L.; Strangwood, M.; Potter, M.; Dixon, S.; Morris, P. F.

    2008-03-01

    Crystallographic texture is generally measured using X-ray diffraction, performed off-line using small samples determining near-surface texture only; electron backscattered diffraction (EBSD) can also be used, but only samples relatively small areas. Ultrasonic methods determine elastic property anisotropy and texture, via orientation distribution coefficients (ODCs), and while there is substantial literature comparing ultrasonically determined properties with X-ray or neutron diffraction texture, there is little discussion about texture inhomogeneity (place to place in a sheet or through thickness) and sampling volume effects (X-ray compared to EBSD) on the accuracy of the correlations. In this article, the crystallographic texture of nominally pure aluminum and commercial aluminum alloy sheets has been determined by X-ray diffraction and EBSD and used to calculate the elastic anisotropy, which is then compared to ultrasonic electromagnetic acoustic transducer (EMAT) velocity anisotropy taking into account through-thickness texture variations. Significant and consistent spatial variability in texture occurs in the aluminum sheet samples (sheet edge to center and through thickness). Predictions of elastic anisotropy based on surface texture determination, as characterized by X-ray diffraction or surface EBSD, gave poor correlations with EMAT velocity anisotropy when the sample contained significant through thickness texture variations; however, accounting for this using multiple EBSD scans through thickness gave good correlations.

  11. Three-dimensional electromagnetic strong turbulence: Dependence of the statistics and dynamics of strong turbulence on the electron to ion temperature ratio

    NASA Astrophysics Data System (ADS)

    Graham, D. B.; Cairns, Iver H.; Skjaeraasen, O.; Robinson, P. A.

    2012-02-01

    The temperature ratio Ti/Te of ions to electrons affects both the ion-damping rate and the ion-acoustic speed in plasmas. The effects of changing the ion-damping rate and ion-acoustic speed are investigated for electrostatic strong turbulence and electromagnetic strong turbulence in three dimensions. When ion damping is strong, density wells relax in place and act as nucleation sites for the formation of new wave packets. In this case, the density perturbations are primarily density wells supported by the ponderomotive force. For weak ion damping, corresponding to low Ti/Te, ion-acoustic waves are launched radially outwards when wave packets dissipate at burnout, thereby increasing the level of density perturbations in the system and thus raising the level of scattering of Langmuir waves off density perturbations. Density wells no longer relax in place so renucleation at recent collapse sites no longer occurs, instead wave packets form in background low density regions, such as superpositions of troughs of propagating ion-acoustic waves. This transition is found to occur at Ti/Te ≈ 0.1. The change in behavior with Ti/Te is shown to change the bulk statistical properties, scaling behavior, spectra, and field statistics of strong turbulence. For Ti/Te>rsim0.1, the electrostatic results approach the predictions of the two-component model of Robinson and Newman, and good agreement is found for Ti/Te>rsim0.15.

  12. The effect of Non- ionizing electromagnetic field with a frequency of 50 Hz in Rat ovary: A transmission electron microscopy study

    PubMed Central

    Khaki, Amir Afshin; Khaki, Arash; Ahmadi, Seyed Shahin

    2016-01-01

    Background: Recently, there are increasing concerns and interests about the potential effects of Electromagnetic Field (EMF) on both human and animal health. Objective: The goal of this study was to evaluate the harmful effects of 50 Hz non-ionizing EMF on rat oocytes. Materials and Methods: In this experimental study 30 rats were randomly taken from laboratory animals and their ags and weights were determined. These 3 month's old rats were randomly divided into 3 groups. The control group consisted of 10 rats without receiving any treatment and kept under normal conditions. Experimental group 1 (10 rats) received EMF for 8 weeks (3 weeks intrauterine +5 weeks after births) and experimental group 2 (10 rats) received EMF for 13 weeks (3 weeks intrauterine +10 weeks after birth). After removing the ovaries and isolating follicles, granulosa cells were fixed in glutaraldehyde and osmium tetroxide. Electron microscopy was used to investigate the traumatic effects of EMF on follicles. Results: In control group nucleus membrane and mitochondria in follicle’s cytoplasm seemed normal in appearance. Theca layer of primary follicles in experimental group was separated clearly, zona layer demonstrated trot with irregular thickness and ovarian stroma seemed isolated with dilated vessels showing infiltration. Conclusion: According to the results of this study, it can be concluded that EMF has harmful effects on the ovarian follicles. PMID:27200427

  13. Direct observation of transition to electron Bernstein waves from electromagnetic mode by three mode-conversion scenarios in the dipole confinement torus plasma

    NASA Astrophysics Data System (ADS)

    Uchijima, K.; Takemoto, T.; Morikawa, J.; Ogawa, Y.

    2015-06-01

    Direct measurement experiments on the mode conversion to the electron Bernstein wave (EBW) have been conducted in dipole confinement torus plasmas for three excitation scenarios; i.e. perpendicular injections of an eXtraordinary mode (X-mode) from the low- and high-magnetic-field sides, and the oblique injection of an Ordinary mode (O-mode) from the low-magnetic-field side. By inserting probe antennas into plasmas, wave propagation has been directly measured. At plasma conditions for the EBW excitation, several characteristics which indicate the mode conversion to the EBWs have been observed; i.e. a short wavelength wave, an electrostatic and longitudinal mode, backward propagation at the upper hybrid resonance (UHR) region. Meanwhile, the wavelengths experimentally observed might be slightly longer than those of theoretical prediction. In the case of the oblique injection of the O-mode, it has been identified that the window of the injection angle for the excitation of the EBW would be quite limited, and the optimum angle seems to be roughly in agreement with theory. These experimental results might support that the electromagnetic waves injected outside of torus plasmas reach to the UHR region and convert wave characteristics to the EBWs for three excitation scenarios.

  14. Extensive theoretical study on electronically excited states of calcium monochloride: Molecular laser cooling and production of ultracold chlorine atoms

    NASA Astrophysics Data System (ADS)

    Fu, Mingkai; Ma, Haitao; Cao, Jianwei; Bian, Wensheng

    2016-05-01

    Nine doublet Λ-S states of calcium monochloride (CaCl) are calculated using the internally contracted multireference configuration interaction method with the Davidson correction. Both the core subvalence and spin-orbit coupling effects are taken into account. Laser cooling of CaCl and production of ultracold chlorine atoms are investigated and assessed. Our computed spectroscopic constants and radiative lifetimes match the available experimental data very well. The determined Franck-Condon factors and vibrational branching ratios of the A 2 Π 1 / 2 ( ν ' ) ← X 2 Σ1 / 2 + ( ν ) transition are highly diagonally distributed and the evaluated radiative lifetime for the A2Π1/2(ν' = 0) state is 28.2 ns, which is short enough for rapid laser cooling. Subsequently, detection of cold molecules via resonance enhanced multiphoton ionization to determine the final quantum state populations is discussed and the ionization energy calculated. A multi-pulse excitation scheme is proposed for producing ultracold chlorine atoms from zero-energy photodissociation of the cooled CaCl. Our results demonstrate the possibility of producing ultracold CaCl molecules and Cl atoms.

  15. Stochastic Cooling

    SciTech Connect

    Blaskiewicz, M.

    2011-01-01

    Stochastic Cooling was invented by Simon van der Meer and was demonstrated at the CERN ISR and ICE (Initial Cooling Experiment). Operational systems were developed at Fermilab and CERN. A complete theory of cooling of unbunched beams was developed, and was applied at CERN and Fermilab. Several new and existing rings employ coasting beam cooling. Bunched beam cooling was demonstrated in ICE and has been observed in several rings designed for coasting beam cooling. High energy bunched beams have proven more difficult. Signal suppression was achieved in the Tevatron, though operational cooling was not pursued at Fermilab. Longitudinal cooling was achieved in the RHIC collider. More recently a vertical cooling system in RHIC cooled both transverse dimensions via betatron coupling.

  16. Electromagnetic Reciprocity.

    SciTech Connect

    Aldridge, David F.

    2014-11-01

    A reciprocity theorem is an explicit mathematical relationship between two different wavefields that can exist within the same space - time configuration. Reciprocity theorems provi de the theoretical underpinning for mod ern full waveform inversion solutions, and also suggest practical strategies for speed ing up large - scale numerical modeling of geophysical datasets . In the present work, several previously - developed electromagnetic r eciprocity theorems are generalized to accommodate a broader range of medi um, source , and receiver types. Reciprocity relations enabling the interchange of various types of point sources and point receivers within a three - dimensional electromagnetic model are derived. Two numerical modeling algorithms in current use are successfully tested for adherence to reciprocity. Finally, the reciprocity theorem forms the point of departure for a lengthy derivation of electromagnetic Frechet derivatives. These mathe matical objects quantify the sensitivity of geophysical electromagnetic data to variatio ns in medium parameters, and thus constitute indispensable tools for solution of the full waveform inverse problem. ACKNOWLEDGEMENTS Sandia National Labor atories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000. Signif icant portions of the work reported herein were conducted under a Cooperative Research and Development Agreement (CRADA) between Sandia National Laboratories (SNL) and CARBO Ceramics Incorporated. The author acknowledges Mr. Chad Cannan and Mr. Terry Pa lisch of CARBO Ceramics, and Ms. Amy Halloran, manager of SNL's Geophysics and Atmospheric Sciences Department, for their interest in and encouragement of this work. Special thanks are due to Dr . Lewis C. Bartel ( recently retired from Sandia National Labo ratories and now a geophysical consultant ) and Dr. Chester J. Weiss (recently rejoined with Sandia National Laboratories) for many stimulating (and reciprocal!) discussions regar ding the topic at hand.

  17. Conduction cooling: multicrate fastbus hardware

    SciTech Connect

    Makowiecki, D.; Sims, W.; Larsen, R.

    1980-11-01

    Described is a new and novel approach for cooling nuclear instrumentation modules via heat conduction. The simplicity of liquid cooled crates and ease of thermal management with conduction cooled modules are described. While this system was developed primarily for the higher power levels expected with Fastbus electronics, it has many general applications.

  18. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Modeling and Computing Example for Effective Electromagnetic Parameters of Multiphase Composite Media

    NASA Astrophysics Data System (ADS)

    Song, Wei-Li; Yuan, Jie; Hou, Zhi-Ling; Cao, Mao-Sheng

    2009-05-01

    A method using strong fluctuation theory (SFT) to compute the effective electromagnetic parameters of multiphase composite media, and common materials used to design radar-absorbing materials, is demonstrated. The effective electromagnetic parameters of ultrafine carbonyl-iron (DT-50) and fiber fabric, which are both multiphase composite media and represent coated and structured radar absorbing materials, respectively, are investigated, and the corresponding equations of electromagnetic parameters by using the SFT are attained. Moreover, we design a program to simplify the solutions, and the results are discussed.

  19. Electromagnetic Particle-in-Cell Simulations of the Solar Wind Interaction with Lunar Magnetic Anomalies: Ion and Electron Dynamics Under Varying Solar Wind Conditions.

    NASA Astrophysics Data System (ADS)

    Deca, J.; Divin, A. V.; Lapenta, G.; Lembege, B.; Markidis, S.; Horanyi, M.

    2014-12-01

    We present three-dimensional fully kinetic and electromagnetic simulations of the solar wind interaction with lunar crustal magnetic anomalies (LMAs). Using the implicit particle-in-cell code iPic3D, we confirm that LMAs may indeed be strong enough to stand off the solar wind from directly impacting the lunar surface forming a mini-magnetosphere, as suggested by spacecraft observations and theory. In contrast to earlier MHD and hybrid simulations, the fully kinetic nature of iPic3D allows to investigate the space charge effects and in particular the electron dynamics dominating the near-surface lunar plasma environment. We describe the general picture of the interaction of a dipole model centered just below the lunar surface under various solar wind and plasma conditions, and focus afterwards on the ion and electron kinetic behavior of the system. It is shown that the configuration is dominated by electron motion, because the LMA scale size is small with respect to the gyroradius of the solar wind ions. The dominant LMA interaction mechanism is also highly dependent on the solar wind and IMF conditions. Driven by strong pressure anisotropies, the mini-magnetosphere is also unstable over time, leading to only temporal shielding of the surface underneath. Our work opens new frontiers of research toward a deeper understanding of LMAs and is ideally suited to be compared with field or particle observations from spacecraft such as Kaguya (SELENE), Lunar Prospector or ARTEMIS. The ability to evaluate the implications for future lunar exploration as well as lunar science in general hinges on a better understanding of LMAs. This research has received funding from the European Commission's FP7 Program with the grant agreement SWIFF (project 2633430, swiff.eu) and EHEROES (project 284461, www.eheroes.eu). The simulations were conducted on the computational resources provided by the PRACE Tier-0 project 2011050747 (Curie) and 2013091928 (SuperMUC). This research was supported by the Swedish National Space Board, Grant No. 136/11. JD has received support through the HPC-Europa2 visitor programme (project HPC08SSG85) and the KuLeuven Junior Mobility Programme Special Research Fund.

  20. Anisotropic conducting films for electromagnetic radiation applications

    DOEpatents

    Cavallo, Francesca; Lagally, Max G.; Rojas-Delgado, Richard

    2015-06-16

    Electronic devices for the generation of electromagnetic radiation are provided. Also provided are methods for using the devices to generate electromagnetic radiation. The radiation sources include an anisotropic electrically conducting thin film that is characterized by a periodically varying charge carrier mobility in the plane of the film. The periodic variation in carrier mobility gives rise to a spatially varying electric field, which produces electromagnetic radiation as charged particles pass through the film.

  1. Electron Emission Rates and Target Current for a Cooled LiNbO-3 Crystal vs. Time, Temperature and Pressure

    NASA Astrophysics Data System (ADS)

    Shafroth, S. M.; Bedair, Sarah; Karwowski, Hugon; Brownridge, J. D.

    2002-05-01

    To compliment the comprehensive study of X-Ray Generation, crystal surface charge and light production vs. time and temperature for different pyroelectric crystals by Brownridge and Raboy^1,we have observed electron emission^2 vs pressure and temperature for a 4 mm diam x 10 mm long cylindrical LiNbO-3 crystal using the cubical chamber and LaBVIEW program described in the previous abstract. The experimental arrangement at Chapel Hill for studying the electron emission rate consists of an insulated target rod and a target of copper evaporated onto a thin Al foil with a pin-hole in the center to allow electrons to reach the surface barrier detector (necessary to avoid swamping the electron detector). Typical electron production rate as well as target current vs. time for different maximum temperatures and pressures for air will be presented and the relationship with the data of Brownridge and Raboy where possible will be discussed. 1. J.D. Brownridge, and S. Raboy, J. Appl. Phys. 86, 640 (1999) 2. 1 J.D. Brownridge, S. M. Shafroth, D. Trott, B. Stoner, W. Hooke, Appl. Phys. Lett, 79, 3364 (2001)

  2. Electromagnetic microactuators

    NASA Astrophysics Data System (ADS)

    Büttgenbach, S.; Al-Halhouli, A. T.; Feldmann, M.; Seidemann, V.; Waldschik, A.

    2013-05-01

    High precision microactuators have become key elements for many applications of MEMS, for example for positioning and handling systems as well as for microfluidic devices. Electromagnetic microactuators exhibit considerable benefits such as high forces, large deflections, low input impedances and thus, the involvement of only low voltages. Most of the magnetic microactuators developed so far are based on the variable reluctance principle and use soft magnetic materials. Since the driving force of such actuators is proportional to their volume, they require structures with rather great heights and aspect ratios. Therefore, the development of new photo resists, which allow UV exposure of thick layers of resist, has been essential for the advancement of variable reluctance microactuators. On the other hand, hard magnetic materials have the potential for larger forces and larger deflections. Accordingly, polymer magnets, in which micro particles of hard magnetic material are suspended in a polymer matrix, have been used to fabricate permanent magnet microactuators. In this paper we give an overview of sophisticated electromagnetic microactuators which have been developed in our laboratory in the framework of the Collaborative Research Center "Design and Manufacturing of Active Microsystems". In particular, concept, fabrication and test of variable reluctance micro stepper motors, of permanent magnet synchronous micromotors and of microactuators based on the Lorentz force principle will be described. Special emphasis will be given to applications in lab-on-chip systems.

  3. Ultrashort electromagnetic pulses in graphene with disorder

    NASA Astrophysics Data System (ADS)

    Konobeeva, N. N.; Belonenko, M. B.

    2015-08-01

    Maxwell's equations describing an electromagnetic field propagating in graphene with disorder are analyzed. The spectrum of electrons for the graphene subsystem is chosen based on the renormalization group approach. An effective equation governing the vector potential of the electromagnetic field is derived and solved numerically. The dependence of the pulse shape on parameters of the problem is investigated.

  4. Development of the Measurement System for the Search of an Electric Dipole Moment of the Electron with Laser-Cooled Francium Atoms

    NASA Astrophysics Data System (ADS)

    Inoue, T.; Ando, S.; Aoki, T.; Arikawa, H.; Ezure, S.; Harada, K.; Hayamizu, T.; Ishikawa, T.; Itoh, M.; Kato, K.; Kato, T.; Kawamura, H.; Nataraj, H. S.; Sato, T.; Uchiyama, A.; Aoki, T.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Shimizu, Y.; Wakasa, T.; Yoshida, H. P.; Sakemi, Y.

    2014-03-01

    We plan to measure the permanent electric dipole moment (EDM) of the electron, which has the sensitivity to the CP violation in theories beyond the standard model by using the laser-cooled francium (Fr) atom. This paper reports the present status of the EDM measurement system. A high voltage application system was constructed in order to produce the strong electric field (100 kV/cm) needed for the experiment. After conditioning, the leakage current was 10 pA when a high voltage of 43 kV was applied. Also, a drift of an environmental field was measured at the planned location of the Fr-EDM experiment. The drift is suppressed at present down to the level of 10 pT by installing a 4-layermagnetic shield. Improvements are still needed to reach the required field stability of 1 fT.

  5. The CMS Electromagnetic Calorimeter

    NASA Astrophysics Data System (ADS)

    Ryan, M.

    2008-06-01

    The CMS experiment at the CERN Large Hadron Collider has placed great emphasis on precise calorimetry. The electromagnetic calorimeter (ECAL) contains 75000 scintillating lead tungstate crystals that are read out using sophisticated electronics; this paper describes these technologies and how they were implemented in the calorimeter. The results of pre-calibration measurements for the detector modules are detailed. Installation of the ECAL into the underground cavern has commenced and the commissioning process and its status are discussed. The experiment is scheduled to start in 2008 and prospects for the first year of operation and running are given.

  6. Antiproton cooling in the Fermilab Recycler Ring

    SciTech Connect

    Nagaitsev, S.; Bolshakov, A.; Broemmelsiek, D.; Burov, Alexey V.; Carlson, K.; Gattuso, C.; Hu, M.; Kazakevich, G.; Kramper, B.; Kroc, T.; Leibfritz, J.; Prost, L.; Pruss, S.; Saewert, G; Schmidt, C.W.; Seletskiy, S.; Shemyakin, A.; Sutherland, M.; Tupikov, V.; Warner, A.; Zenkevich, P.; /Fermilab /Moscow, ITEP /Novosibirsk, IYF /Rochester U.

    2005-12-01

    The 8.9-GeV/c Recycler antiproton storage ring is equipped with both stochastic and electron cooling systems. These cooling systems are designed to assist accumulation of antiprotons for the Tevatron collider operations. In this paper we report on an experimental demonstration of electron cooling of high-energy antiprotons. At the time of writing this report, the Recycler electron cooling system is routinely used in collider operations. It has helped to set recent peak luminosity records.

  7. Antiproton Cooling in the Fermilab Recycler Ring

    SciTech Connect

    Nagaitsev, S.; Broemmelsiek, D.; Burov, A.; Carlson, K.; Gattuso, C.; Hu, M.; Kramper, B.; Kroc, T.; Leibfritz, J.; Prost, L.; Pruss, S.; Saewert, G.; Schmidt, C. W.; Shemyakin, A.; Sutherland, M.; Tupikov, V.; Warner, A.; Bolshakov, A.; Zenkevich, P.; Kazakevich, G.

    2006-03-20

    The 8.9-GeV/c Recycler antiproton storage ring is equipped with both stochastic and electron cooling systems. These cooling systems are designed to assist accumulation of antiprotons for the Tevatron collider operations. In this paper we report on an experimental demonstration of electron cooling of high-energy antiprotons. At the time of writing this report, the Recycler electron cooling system is routinely used in collider operations. It has helped to set recent peak luminosity records.

  8. Electromagnetic effects on geodesic acoustic modes

    SciTech Connect

    Bashir, M. F.; Smolyakov, A. I.; Elfimov, A. G.; Melnikov, A. V.; Murtaza, G.

    2014-08-15

    By using the full electromagnetic drift kinetic equations for electrons and ions, the general dispersion relation for geodesic acoustic modes (GAMs) is derived incorporating the electromagnetic effects. It is shown that m = 1 harmonic of the GAM mode has a finite electromagnetic component. The electromagnetic corrections appear for finite values of the radial wave numbers and modify the GAM frequency. The effects of plasma pressure β{sub e}, the safety factor q, and the temperature ratio τ on GAM dispersion are analyzed.

  9. Self-Consistent Model of Magnetospheric Ring Current and Propagating Electromagnetic Ion Cyclotron Waves. 2; Waves, Precipitating Ring Current Ions, and Thermal Electron Heating

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Gamayunov, K. V.; Gallagher, D. L.

    2006-01-01

    This paper is dedicated to further presentations and discussions of the results from our new global self-consistent theoretical model of interacting ring current ions and electromagnetic ion cyclotron waves [Khazanov et al., 2006; here referred to as Paper 1]. In order to adequately take into account the wave propagation and refraction in a multi-ion plasmasphere, we explicitly include the ray tracing equations in our previous self-consistent model and use the general form of the wave kinetic equation [for details see Paper 1]. To demonstrate the effects of the EMIC wave propagation and refraction on the RC proton precipitations and heating of the thermal plasmaspheric electrons we simulate the May 1998 storm. The main findings of our simulation can be summarized as follows. Firstly, the wave induced precipitations have a quite fine structure, and are highly organized by location of the plasmapause gradient. The strongest fluxes of about 4 (raised dot) 10(exp 6) [(cm (raised dot) s (raised dot) sr)(sup -l)] are observed during the main and early recovery phases of the storm. The very interesting and probably more important finding is that in a number of cases the most intense precipitating fluxes are not simply connected to the most intense EMIC waves. The character of the EMIC wave power spectral density distribution over the equatorial wave normal angle is an extremely crucial for the effectiveness of the RC ion scattering. Secondly, comparison of the global proton precipitating patterns with the results from other ring current model [Kozyra et al., 1997] reveals that although we observe a qualitative agreement between localizations of the wave induced fluxes in the models, there is no quantitative agreement between the magnitudes of these fluxes. These differences are mainly due to a qualitative difference between the characters of the EMIC wave power spectral density distributions over the equatorial wave normal angle. Finally, the two energy sources to the plasmaspheric electrons are considered; (i) the heat fluxes caused by the EMIC wave energy absorption due to Landau resonance, and (ii) the heat fluxes due to Coulomb energy degradation of the RC o(+) ions. The heat fluxes caused by the EMIC wave energy absorption due to Landau resonance are observed in the postnoon-premidnight MLT sector, and maximize at the magnitude of 10l1 (eV/(cm(sup 2)(raised dot) s) at L=3.25, MLT=22 at 3400 UT after 1 May, 0000 UT. The greatest Coulomb energy deposition rates are about 2 (raised dot) 10(sup 10)(eV/(cm(sup 2)(raised dot) s) and observed during two periods; 32-48 hours, and 76-86 hours after 1 May, 0000 UT. The theoretically derived spatial structure of the thermal electron heating caused by interaction of the RC with plasmasphere is strongly supported by concurrent and conjugate plasma measurements from the plasmasphere, the RC, and the topside ionosphere [Gurgiolo et al., 20051.

  10. Cooling wall

    SciTech Connect

    Nosenko, V.I.

    1995-07-01

    Protecting the shells of blast furnaces is being resolved by installing cast iron cooling plates. The cooling plates become non-operational in three to five years. The problem is that defects occur in manufacturing the cooling plates. With increased volume and intensity of work placed on blast furnaces, heat on the cast iron cooling plates reduces their reliability that limits the interim repair period of blast furnaces. Scientists and engineers from the Ukraine studied this problem for several years, developing a new method of cooling the blast furnace shaft called the cooling wall. Traditional cast iron plates were replaced by a screen of steel tubes, with the area between the tubes filled with fireproof concrete. Before placing the newly developed furnace shaft into operation, considerable work was completed such as theoretical calculations, design, research of temperature fields and tension. Continual testing over many years confirms the value of this research in operating blast furnaces. The cooling wall works with water cooling as well as vapor cooling and is operating in 14 blast furnaces in the Ukraine and two in Russia, and has operated for as long as 14 years.

  11. Evidence that the maximum electron energy in hotspots of FR II galaxies is not determined by synchrotron cooling

    NASA Astrophysics Data System (ADS)

    Araudo, Anabella T.; Bell, Anthony R.; Crilly, Aidan; Blundell, Katherine M.

    2016-05-01

    It has been suggested that relativistic shocks in extragalactic sources may accelerate the highest energy cosmic rays. The maximum energy to which cosmic rays can be accelerated depends on the structure of magnetic turbulence near the shock but recent theoretical advances indicate that relativistic shocks are probably unable to accelerate particles to energies much larger than a PeV. We study the hotspots of powerful radiogalaxies, where electrons accelerated at the termination shock emit synchrotron radiation. The turnover of the synchrotron spectrum is typically observed between infrared and optical frequencies, indicating that the maximum energy of non-thermal electrons accelerated at the shock is ≲ TeV for a canonical magnetic field of ˜100 μG. Based on theoretical considerations we show that this maximum energy cannot be constrained by synchrotron losses as usually assumed, unless the jet density is unreasonably large and most of the jet upstream energy goes to non-thermal particles. We test this result by considering a sample of hotspots observed with high spatial resolution at radio, infrared and optical wavelengths.

  12. COOLING DYNAMICS STUDIES AND SCENARIOS FOR THE RHIC COOLER.

    SciTech Connect

    FEDOTOV,A.V.; BEN-ZVI,I.; LITVINENKO, V.

    2005-05-16

    In this paper, we discuss various electron cooling dynamics studies for RHIC. We also present simulations [1] of various possibilities of using electron cooling at RHIC, which includes cooling at the top energy, pre-cooling at low energy, aspects of transverse and longitudinal cooling and their impact on the luminosity. Electron cooling at various collision energies both for heavy ions and protons is also discussed.

  13. Electromagnetic Gravitation

    NASA Astrophysics Data System (ADS)

    Montgomery, Jerry; Russell, Philmore

    2005-03-01

    Recent analysis of radio metric data from several space probes deployed by NASA indicate that they are being slowed by an anomalous constant acceleration with an average magnitude of 8x10-10m/s^2 oriented with respect to the sun. Analysis of their slowdown, in addition to many other anomalous astrophysical phenomena indicates that a negative curvature of the space-time continuum is produced by the electromagnetic radiation of the sun. The acceleration appears to have a close relation to the wavelength λat which the sun radiates most intensely. The evidence that supports our hypothesis may also provide solutions to the flat rotation curve of the galaxy, and rogue stars and planets within the galaxy. Calculations using the data concerning the four probes result in the formula -a=c^2λ which expresses a negative acceleration that is proportional to the speed of light divided by the peak wavelength, multiplied by a new constant k. The evidence also gives a strong indication that light, in addition to its particle-wave nature, produces gravitational field-like characteristics through interacting with the space-time continuum.

  14. Electromagnetic gravitation

    NASA Astrophysics Data System (ADS)

    Montgomery, Jerry, , Dr.

    2005-04-01

    Recent analysis of radio metric data from several space probes deployed by NASA indicate that they are being slowed by an anomalous constant acceleration with an average magnitude of 8x10-10m/s^2 oriented with respect to the sun. Analysis of their slowdown, in addition to many other anomalous astrophysical phenomena indicates that a negative curvature of the space-time continuum is produced by the electromagnetic radiation of the sun. The acceleration appears to have a close relation to the wavelength λat which the sun radiates most intensely. The evidence that supports our hypothesis may also provide solutions to the flat rotation curve of the galaxy, and rogue stars and planets within the galaxy. Calculations using the data concerning the four probes result in the formula -a=c^2λ which expresses a negative acceleration that is proportional to the speed of light divided by the peak wavelength, multiplied by a new constant k. The evidence also gives a strong indication that light, in addition to its particle-wave nature, produces gravitational field-like characteristics through interacting with the space-time continuum.

  15. Electromagnetic Transport From Microtearing Mode Turbulence

    SciTech Connect

    Guttenfelder, W; Kaye, S M; Nevins, W M; Wang, E; Bell, R E; Hammett, G W; LeBlanc, B P; Mikkelsen, D R

    2011-03-23

    This Letter presents non-linear gyrokinetic simulations of microtearing mode turbulence. The simulations include collisional and electromagnetic effects and use experimental parameters from a high beta discharge in the National Spherical Torus Experiment (NSTX). The predicted electron thermal transport is comparable to that given by experimental analysis, and it is dominated by the electromagnetic contribution of electrons free streaming along the resulting stochastic magnetic field line trajectories. Experimental values of flow shear can significantly reduce the predicted transport.

  16. Electromagnetic Transport from Microtearing Mode Turbulence

    SciTech Connect

    Guttenfelder, W.; Kaye, S. M.; Bell, R. E.; Hammett, G. W.; LeBlanc, B. P.; Mikkelsen, D. R.; Candy, J.; Nevins, W. M.; Wang, E.; Yuh, H.

    2011-04-15

    This Letter presents nonlinear gyrokinetic simulations of microtearing mode turbulence. The simulations include collisional and electromagnetic effects and use experimental parameters from a high-{beta} discharge in the National Spherical Torus Experiment. The predicted electron thermal transport is comparable to that given by experimental analysis, and it is dominated by the electromagnetic contribution of electrons free-streaming along the resulting stochastic magnetic field line trajectories. Experimental values of flow shear can significantly reduce the predicted transport.

  17. Cool Shelter

    ERIC Educational Resources Information Center

    Praeger, Charles E.

    2005-01-01

    Amid climbing energy costs and tightening budgets, administrators at school districts, colleges and universities are looking for all avenues of potential savings while promoting sustainable communities. Cool metal roofing can save schools money and promote sustainable design at the same time. Cool metal roofing keeps the sun's heat from collecting

  18. Cool Shelter

    ERIC Educational Resources Information Center

    Praeger, Charles E.

    2005-01-01

    Amid climbing energy costs and tightening budgets, administrators at school districts, colleges and universities are looking for all avenues of potential savings while promoting sustainable communities. Cool metal roofing can save schools money and promote sustainable design at the same time. Cool metal roofing keeps the sun's heat from collecting…

  19. Cool Suit

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Acurex developed a heat stress alleviating, liquid cooled helmet liner for military pilots after a series of accidents in Vietnam suggested heat exhaustion as the cause. System pumped a cooled liquid through channels in the helmet liner proved effective in eliminating 40-60% of stored body heat.

  20. Noise and Bandwidth Measurements of Diffusion-Cooled Nb Hot-Electron Bolometer Mixers at Frequencies Above the Superconductive Energy Gap

    NASA Technical Reports Server (NTRS)

    Wyss, R. A.; Karasik, B. S.; McGrath, W. R.; Bumble, B.; LeDuc, H.

    1999-01-01

    Diffusion-cooled Nb hot-electron bolometer (HEB) mixers have the potential to simultaneously achieve high intermediate frequency (IF) bandwidths and low mixer noise temperatures for operation at THz frequencies (above the superconductive gap energy). We have measured the IF signal bandwidth at 630 GHz of Nb devices with lengths L = 0.3, 0.2, and 0.1 micrometer in a quasioptical mixer configuration employing twin-slot antennas. The 3-dB EF bandwidth increased from 1.2 GHz for the 0.3 gm long device to 9.2 GHz for the 0.1 gm long device. These results demonstrate the expected 1/L squared dependence of the IF bandwidth at submillimeter wave frequencies for the first time, as well as the largest EF bandwidth obtained to date. For the 0.1 gm device, which had the largest bandwidth, the double sideband (DSB) noise temperature of the receiver was 320-470 K at 630 GHz with an absorbed LO power of 35 nW, estimated using the isothermal method. A version of this mixer with the antenna length scaled for operation at 2.5 THz has also been tested. A DSB receiver noise temperature of 1800 plus or minus 100 K was achieved, which is about 1,000 K lower than our previously reported results. These results demonstrate that large EF bandwidth and low-noise operation of a diffusion-cooled HEB mixer is possible at THz frequencies with the same device geometry.

  1. Beam cooling: Principles and achievements

    SciTech Connect

    Mohl, Dieter; Sessler, Andrew M.

    2003-05-18

    After a discussion of Liouville's theorem, and its implications for beam cooling, a brief description is given of each of the various methods of beam cooling: stochastic, electron, radiation, laser, ionization, etc. For each, we present the type of particle for which it is appropriate, its range of applicability, and the currently achieved degree of cooling. For each method we also discuss the present applications and, also, possible future developments and further applications.

  2. Narrow field electromagnetic sensor system and method

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments.

  3. Narrow field electromagnetic sensor system and method

    DOEpatents

    McEwan, T.E.

    1996-11-19

    A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs.

  4. k-space drift due to the density variation as a cause of electromagnetic emission generation of type III solar radio bursts by a non-gyrotropic electron beam

    NASA Astrophysics Data System (ADS)

    Tsiklauri, David; Schmitz, Holger

    2013-04-01

    It is widely accepted that there is a correlation between super-thermal electron beams and type III solar radio bursts. Whilst the correlation is an established fact, the actual mechanism that generates the type III burst emission is not yet fully determined. The main source of the uncertainty is current inability to send in-situ probes at distances 0.15 - 1.5Rsun from the solar surface (photosphere). The most widely accepted mechanism, that historically appeared first is the plasma emission. In plasma emission mechanism quasilinear theory, kinetic Fokker-Planck type equation for describing the dynamics of an electron beam is used, in conjunction with the spectral energy density evolutionary equations for Langmuir and ion-sound waves. Further, non-linear wave-wave interactions between Langmuir, ion-acoustic and EM waves produce emission at electron plasma frequency, ?pe or the second harmonic, 2?pe. A variant of the plasma emission mechanism is the stochastic growth theory, where density irregularities produce a random growth, in such a way that Langmuir waves are generated stochastically and quasilinear interactions within the Langmuir clumps cause the beam to fluctuate about marginal stability. The latter models have been used for producing the solar type III burst observable parameters. Other possible mechanisms include: linear mode conversion, antenna radiation and non-gyrotropic electron beam emission [1]. Recent works [2,3] elucidated further the non-gyrotropic electron beam emission, first proposed in Ref.[1]. In particular, the effect of electron beam pitch angle and density gradient on solar type III radio bursts was studied [2] and the role of electron cyclotron maser (ECM) emission with a possible mode coupling to the z-mode was explored [3]. In this contribution and paper [4], using large-scale Particle-In-Cell simulations, we explore the non-gyrotropic electron beam emission mechanism by studying the effects of electron beam kinetics and k-space drift, in long term evolution of electromagnetic emission generation of type III solar radio bursts. The following improvements and progress in understanding of the radio emission mechanism are made: (i) Improved numerical simulations with larger spatial domain and longer end-simulation times; (ii) The electron beam injection on a density plateau followed by a decreasing density gradient that mimics the Sun-earth system; (iii) Consideration of a ring and shifted ring electron initial velocity distribution functions; (iv) The role of the k-space drift in the radio emission; (v) Estimation of the ECM growth rate and its role in the emission generation. It is worthwhile to note that Ref.[3] proposed mode coupling on the density gradient as a source of radio emission as opposed to the k-space drift advocated in the present work. The situation is analogous to the auroral waves emitted near the plasma frequency in Earth auroral ionosphere [A. Layden, I. H. Cairns, P. A. Robinson, and J. LaBelle, J. Geophys. Res. 116, A12328 (2011)]. [1] D. Tsiklauri, "An alternative to the plasma emission model: Particle-In-Cell, self-consistent electromagnetic wave emission simulations of solar type III radio bursts", Physics of Plasmas 18, 052903 (2011) [2] R. Pechhacker, D. Tsiklauri, "The effect of electron beam pitch angle and density gradient on solar type III radio bursts", Phys. Plasmas 19, 112903 (2012) [3] R. Pechhacker, D. Tsiklauri, "Electron cyclotron maser emission mode coupling to the z-mode on a longitudinal density gradient in the context of solar type III bursts", Phys. Plasmas 19, 110702 (2012) [4] H. Schmitz, D. Tsiklauri, "k-space drift due to the density variation as a cause of electromagnetic emission generation of type III solar radio bursts by a non-gyrotropic electron beam", Phys. Plasmas, in preparation, (2013)

  5. Precision Experiments With Stored And Cooled Highly Charged Ions

    SciTech Connect

    Kluge, H.-Juergen

    2006-11-07

    Accumulation, storing and cooling techniques play an increasingly important role in many areas of science. These procedures can be applied in Penning traps and storage rings to ions. In this way, quantum electrodynamics can be tested in extreme electromagnetic fields by measuring hyperfine structure splittings. Lamb shifts, or g-factors in hydrogen-like heavy systems such as U91+ or Pb81+. In addition, fundamental constants or nuclear properties like the atomic mass can be determined. In the case of a radioactive ion, the fate of an individual ion, undergoing a nuclear decay, can be studied in detail by observing the disappearance of the signal of the mother and the appearance of that of the daughter isotope. Presently, the Highly-charged Ion TRAP (HITRAP) facility is being built up at GSI. Stable or radioactive highly charged ions are produced by colliding relativistic ions with a target. After electron cooling and deceleration in the storage ring ESR at GSI, these ions are ejected, decelerated further, and injected into a Penning trap where cooling to 4 K takes place. From there, the cooled highly charged ions such as hydrogen-like uranium are transferred at low energy to different experimental set-ups which are being built up by the international HITRAP Collaboration.

  6. Cooled railplug

    DOEpatents

    Weldon, William F.

    1996-01-01

    The railplug is a plasma ignitor capable of injecting a high energy plasma jet into a combustion chamber of an internal combustion engine or continuous combustion system. An improved railplug is provided which has dual coaxial chambers (either internal or external to the center electrode) that provide for forced convective cooling of the electrodes using the normal pressure changes occurring in an internal combustion engine. This convective cooling reduces the temperature of the hot spot associated with the plasma initiation point, particularly in coaxial railplug configurations, and extends the useful life of the railplug. The convective cooling technique may also be employed in a railplug having parallel dual rails using dual, coaxial chambers.

  7. Electromagnetic radiation from beam-plasma instabilities

    NASA Technical Reports Server (NTRS)

    Stenzel, R. L.; Whelan, D. A.

    1982-01-01

    The mechanism by which unstable electrostatic waves of an electron-beam plasma system are converted into observed electromagnetic waves is of great current interest in space plasma physics. Electromagnetic radiation arises from both natural beam-plasma systems, e.g., type III solar bursts and kilometric radiation, and from man-made electron beams injected from rockets and spacecraft. In the present investigation the diagnostic difficulties encountered in space plasmas are overcome by using a large laboratory plasma. A finite diameter (d approximately equal to 0.8 cm) electron beam is injected into a uniform quiescent magnetized afterglow plasma of dimensions large compared with electromagnetic wavelength. Electrostatic waves grow, saturate and decay within the uniform central region of the plasma volume so that linear mode conversion on density gradients can be excluded as a possible generation mechanism for electromagnetic waves.

  8. Colouring cryo-cooled crystals: online microspectrophotometry

    PubMed Central

    McGeehan, John; Ravelli, Raimond B. G.; Murray, James W.; Owen, Robin Leslie; Cipriani, Florent; McSweeney, Sean; Weik, Martin; Garman, Elspeth F.

    2009-01-01

    X-rays can produce a high concentration of radicals within cryo-cooled macromolecular crystals. Some radicals have large extinction coefficients in the visible (VIS) range of the electromagnetic spectrum, and can be observed optically and spectrally. An online microspectrophotometer with high temporal resolution has been constructed that is capable of measuring UV/VIS absorption spectra (200–1100 nm) during X-ray data collection. The typical X-ray-induced blue colour that is characteristic of a wide range of cryo-conditions has been identified as trapped solvated electrons. Disulphide-containing proteins are shown to form disulphide radicals at millimolar concentrations, with absorption maxima around 400 nm. The solvated electrons and the disulphide radicals seem to have a lifetime in the range of seconds up to minutes at 100 K. The temperature dependence of the kinetics of X-ray-induced radical formation is different for the solvated electrons compared with the disulphide radicals. The online microspectrophotometer provides a technique complementary to X-ray diffraction for analysing and characterizing intermediates and redox states of proteins and enzymes. PMID:19240328

  9. Electromagnetic PIC modeling with a background gas

    NASA Astrophysics Data System (ADS)

    Verboncoeur, J. P.; Cooperberg, D.

    1997-02-01

    Modeling the interaction of relativistic electromagnetic plasmas with a background gas is described. The timescales range over many orders of magnitude, from the electromagnetic Courant condition (˜10-12 sec) to electron-neutral collision times (˜10-7 sec) to ion transit times (˜10-5 sec). For this work, the traditional Monte Carlo algorithm [1] is described for relativistic electrons. Subcycling is employed to improve efficiency, and smoothing is employed to reduce particle noise. Applications include plasma-focused electron guns, gas-filled microwave tubes, surface wave discharges driven at microwave frequencies, and electron-cyclotron resonance discharges. The method is implemented in the OOPIC code [2].

  10. Electromagnetic PIC modeling with a background gas

    SciTech Connect

    Verboncoeur, J. P.; Cooperberg, D.

    1997-02-01

    Modeling the interaction of relativistic electromagnetic plasmas with a background gas is described. The timescales range over many orders of magnitude, from the electromagnetic Courant condition ({approx}10{sup -12} sec) to electron-neutral collision times ({approx}10{sup -7} sec) to ion transit times ({approx}10{sup -5} sec). For this work, the traditional Monte Carlo algorithm [1] is described for relativistic electrons. Subcycling is employed to improve efficiency, and smoothing is employed to reduce particle noise. Applications include plasma-focused electron guns, gas-filled microwave tubes, surface wave discharges driven at microwave frequencies, and electron-cyclotron resonance discharges. The method is implemented in the OOPIC code [2].

  11. Cooling system

    SciTech Connect

    Wildfeuer, R.

    1982-06-15

    A cooling system particularly suitable for use in the airconditioning of buildings is described. The system includes: (A) a cooling zone containing a conduit for cooling fluid, the conduit encountering the heat load, means in the conduit for propelling the fluid through the conduit, and cooling fluid in the conduit; (B) a refrigeration zone containing a closed refrigeration circuit for refrigerant, chiller means in the circuit for extracting energy from the refrigerant, means for circulating refrigerant in the circuit and refrigerant in the circuit; and (C) collection means connected to the refrigeration zone for removing energy extracted by the chiller. The cooling and refrigeration zones are connectable through a heat exchanger for transfer of energy between the fluid and the refrigerant and the refrigerant comprises a slurry of ice and water which may be partly stored in a reservoir constituting part of the refrigeration zone. In this system, a reserve cooling capacity can be stored in the reservoir for use during cyclic requirements therefor.

  12. Gas turbine engine component cooling system

    SciTech Connect

    Colman, M.E.; Goeller, R.E.

    1986-07-22

    An electronic control apparatus is described which is positionable in a cooling fluid environment comprising: a housing for containing an electronic control having an outer surface; a plurality of heat transfer fins extending from the outer surface of the housing and positionable in the cooling fluid environment for cooling the fins and housing; environmental sensor means disposed in and connected to the housing adjacent to the heat transfer fins and being connectible to the electronic control; and the sensor means being positioned in the housing in flow communication with the cooling fluid flowable over the fins for sensing a characteristic of primarily the cooling fluid environment.

  13. Carbon nanotube-copper exhibiting metal-like thermal conductivity and silicon-like thermal expansion for efficient cooling of electronics

    NASA Astrophysics Data System (ADS)

    Subramaniam, Chandramouli; Yasuda, Yuzuri; Takeya, Satoshi; Ata, Seisuke; Nishizawa, Ayumi; Futaba, Don; Yamada, Takeo; Hata, Kenji

    2014-02-01

    Increasing functional complexity and dimensional compactness of electronic devices have led to progressively higher power dissipation, mainly in the form of heat. Overheating of semiconductor-based electronics has been the primary reason for their failure. Such failures originate at the interface of the heat sink (commonly Cu and Al) and the substrate (silicon) due to the large mismatch in thermal expansion coefficients (~300%) of metals and silicon. Therefore, the effective cooling of such electronics demands a material with both high thermal conductivity and a similar coefficient of thermal expansion (CTE) to silicon. Addressing this demand, we have developed a carbon nanotube-copper (CNT-Cu) composite with high metallic thermal conductivity (395 W m-1 K-1) and a low, silicon-like CTE (5.0 ppm K-1). The thermal conductivity was identical to that of Cu (400 W m-1 K-1) and higher than those of most metals (Ti, Al, Au). Importantly, the CTE mismatch between CNT-Cu and silicon was only ~10%, meaning an excellent compatibility. The seamless integration of CNTs and Cu was achieved through a unique two-stage electrodeposition approach to create an extensive and continuous interface between the Cu and CNTs. This allowed for thermal contributions from both Cu and CNTs, resulting in high thermal conductivity. Simultaneously, the high volume fraction of CNTs balanced the thermal expansion of Cu, accounting for the low CTE of the CNT-Cu composite. The experimental observations were in good quantitative concurrence with the theoretically described `matrix-bubble' model. Further, we demonstrated identical in-situ thermal strain behaviour of the CNT-Cu composite to Si-based dielectrics, thereby generating the least interfacial thermal strain. This unique combination of properties places CNT-Cu as an isolated spot in an Ashby map of thermal conductivity and CTE. Finally, the CNT-Cu composite exhibited the greatest stability to temperature as indicated by its low thermal distortion parameter (TDP). Thus, this material presents a viable and efficient alternative to existing materials for thermal management in electronics.Increasing functional complexity and dimensional compactness of electronic devices have led to progressively higher power dissipation, mainly in the form of heat. Overheating of semiconductor-based electronics has been the primary reason for their failure. Such failures originate at the interface of the heat sink (commonly Cu and Al) and the substrate (silicon) due to the large mismatch in thermal expansion coefficients (~300%) of metals and silicon. Therefore, the effective cooling of such electronics demands a material with both high thermal conductivity and a similar coefficient of thermal expansion (CTE) to silicon. Addressing this demand, we have developed a carbon nanotube-copper (CNT-Cu) composite with high metallic thermal conductivity (395 W m-1 K-1) and a low, silicon-like CTE (5.0 ppm K-1). The thermal conductivity was identical to that of Cu (400 W m-1 K-1) and higher than those of most metals (Ti, Al, Au). Importantly, the CTE mismatch between CNT-Cu and silicon was only ~10%, meaning an excellent compatibility. The seamless integration of CNTs and Cu was achieved through a unique two-stage electrodeposition approach to create an extensive and continuous interface between the Cu and CNTs. This allowed for thermal contributions from both Cu and CNTs, resulting in high thermal conductivity. Simultaneously, the high volume fraction of CNTs balanced the thermal expansion of Cu, accounting for the low CTE of the CNT-Cu composite. The experimental observations were in good quantitative concurrence with the theoretically described `matrix-bubble' model. Further, we demonstrated identical in-situ thermal strain behaviour of the CNT-Cu composite to Si-based dielectrics, thereby generating the least interfacial thermal strain. This unique combination of properties places CNT-Cu as an isolated spot in an Ashby map of thermal conductivity and CTE. Finally, the CNT-Cu composite exhibited the greatest stability to temperature as indicated by its low thermal distortion parameter (TDP). Thus, this material presents a viable and efficient alternative to existing materials for thermal management in electronics. Electronic supplementary information (ESI) available: Schematic of in-plane and out-of-plane geometries for measuring thermal conductivity of CNT-Cu, comparison of Raman spectra of pristine CNTs and CNT-Cu. See DOI: 10.1039/c3nr05290g

  14. Advanced Power Electronics and Electric Motors Annual Report -- 2013

    SciTech Connect

    Narumanchi, S.; Bennion, K.; DeVoto, D.; Moreno, G.; Rugh, J.; Waye, S.

    2015-01-01

    This report describes the research into advanced liquid cooling, integrated power module cooling, high temperature air cooled power electronics, two-phase cooling for power electronics, and electric motor thermal management by NREL's Power Electronics group in FY13.

  15. An experimental and ab initio study of the electronic spectrum of the jet-cooled F{sub 2}BO free radical

    SciTech Connect

    Grimminger, Robert; Clouthier, Dennis J.; Sheridan, Phillip M.

    2014-04-28

    We have studied the B{sup ~} {sup 2}A{sub 1}–X{sup ~} {sup 2}B{sub 2} laser-induced fluorescence (LIF) spectrum of the jet-cooled F{sub 2}BO radical for the first time. The transition consists of a strong 0{sub 0}{sup 0} band at 446.5 nm and eight weak sequence bands to shorter wavelengths. Single vibronic level emission spectra obtained by laser excitation of individual levels of the B{sup ~} state exhibit two electronic transitions: a very weak, sparse B{sup ~}–X{sup ~} band system in the 450–500 nm region and a stronger, more extensive set of B{sup ~} {sup 2}A{sub 1}–A{sup ~} {sup 2}B{sub 1} bands in the 580–650 nm region. We have also performed a series of high level ab initio calculations to predict the electronic energies, molecular structures, vibrational frequencies, and rotational and spin-rotation constants in the X{sup ~} {sup 2}B{sub 2}, A{sup ~2}B{sub 1} and B{sup ~} {sup 2}A{sub 1} electronic states as an aid to the analysis of the experimental data. The theoretical results have been used as input for simulations of the rotationally resolved B{sup ~} {sup 2}A{sub 1}–X{sup ~} {sup 2}B{sub 2} 0{sub 0}{sup 0} LIF band and Franck-Condon profiles of the LIF and single vibronic level emission spectra. The agreement between the simulations obtained with purely ab initio parameters and the experimental spectra validates the geometries calculated for the ground and excited states and the conclusion that the radical has C{sub 2v} symmetry in the X{sup ~}, A{sup ~}, and B{sup ~} states. The spectra provide considerable new information about the vibrational energy levels of the X{sup ~} and A{sup ~} states, but very little for the B{sup ~} state, due to the very restrictive Franck-Condon factors in the LIF spectra.

  16. Electromagnetic induction methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electromagnetic induction geophysical methods are finding greater and greater use for agricultural purposes. Electromagnetic induction methods measure the electrical conductivity (or resistivity) for a bulk volume of soil directly beneath the surface. An instrument called a ground conductivity meter...

  17. Overview of Recent Trends in Beam Cooling Methods and Technology

    SciTech Connect

    Meshkov, Igor; Moehl, Dieter

    2006-03-20

    In this introductory paper, we try to give an idea of new developments in beam cooling since COOL03. We will concentrate on trends in electron cooling, stochastic cooling, muon cooling and beam crystallization; trends, which we think, will mark the future. We hope to touch upon some of the major ideas and topics that will be developed in detail at this workshop.

  18. Cooled railplug

    DOEpatents

    Weldon, W.F.

    1996-05-07

    The railplug is a plasma ignitor capable of injecting a high energy plasma jet into a combustion chamber of an internal combustion engine or continuous combustion system. An improved railplug is provided which has dual coaxial chambers (either internal or external to the center electrode) that provide for forced convective cooling of the electrodes using the normal pressure changes occurring in an internal combustion engine. This convective cooling reduces the temperature of the hot spot associated with the plasma initiation point, particularly in coaxial railplug configurations, and extends the useful life of the railplug. The convective cooling technique may also be employed in a railplug having parallel dual rails using dual, coaxial chambers. 10 figs.

  19. Electromagnetically controlled multiferroic thermal diode

    NASA Astrophysics Data System (ADS)

    Chotorlishvili, L.; Etesami, S. R.; Berakdar, J.; Khomeriki, R.; Ren, Jie

    2015-10-01

    We propose an electromagnetically tunable thermal diode based on a two-phase multiferroic composite. Analytical and full numerical calculations for a prototypical heterojunction composed of iron on barium titanate in the tetragonal phase demonstrate a strong heat rectification effect that can be controlled externally by a moderate electric field. This finding is important for thermally based information processing and sensing and can also be integrated in (spin) electronic circuits for heat management and recycling.

  20. Development of a strong electromagnet wiggler

    SciTech Connect

    Burns, M.J.; Deis, G.A.; Holmes, R.H.; Van Maren, R.D.; Halbach, K.

    1987-01-01

    The Strong Electromagnet (SEM) wiggler is a permanent magnet-assisted electromagnet under development at the Lawrence Livermore National Laboratory (LLNL) as part of the Induction Linac Free-Electron-Laser (IFEL) program. This concept uses permanent magnets within the wiggler to provide a reverse bias flux in the iron and thus delay the onset of magnetic saturation. The electromagnet coils determine the wiggler field and operate at low current densities by virtue of their placement away from the midplane. We describe here the design approach used and test data from a 7-period wiggler prototype that includes curved pole tips to provide wiggle-plane focusing. 7 refs.

  1. Effectiveness-weighted control method for a cooling system

    DOEpatents

    Campbell, Levi A.; Chu, Richard C.; David, Milnes P.; Ellsworth Jr., Michael J.; Iyengar, Madhusudan K.; Schmidt, Roger R.; Simons, Robert E.

    2015-12-15

    Energy efficient control of cooling system cooling of an electronic system is provided based, in part, on weighted cooling effectiveness of the components. The control includes automatically determining speed control settings for multiple adjustable cooling components of the cooling system. The automatically determining is based, at least in part, on weighted cooling effectiveness of the components of the cooling system, and the determining operates to limit power consumption of at least the cooling system, while ensuring that a target temperature associated with at least one of the cooling system or the electronic system is within a desired range by provisioning, based on the weighted cooling effectiveness, a desired target temperature change among the multiple adjustable cooling components of the cooling system. The provisioning includes provisioning applied power to the multiple adjustable cooling components via, at least in part, the determined control settings.

  2. Effectiveness-weighted control of cooling system components

    DOEpatents

    Campbell, Levi A.; Chu, Richard C.; David, Milnes P.; Ellsworth Jr., Michael J.; Iyengar, Madhusudan K.; Schmidt, Roger R.; Simmons, Robert E.

    2015-12-22

    Energy efficient control of cooling system cooling of an electronic system is provided based, in part, on weighted cooling effectiveness of the components. The control includes automatically determining speed control settings for multiple adjustable cooling components of the cooling system. The automatically determining is based, at least in part, on weighted cooling effectiveness of the components of the cooling system, and the determining operates to limit power consumption of at least the cooling system, while ensuring that a target temperature associated with at least one of the cooling system or the electronic system is within a desired range by provisioning, based on the weighted cooling effectiveness, a desired target temperature change among the multiple adjustable cooling components of the cooling system. The provisioning includes provisioning applied power to the multiple adjustable cooling components via, at least in part, the determined control settings.

  3. Principles of electromagnetic theory

    SciTech Connect

    Kovetz, A.H. )

    1990-01-01

    This book emphasizes the fundamental understanding of the laws governing the behavior of charge and current carrying bodies. Electromagnetism is presented as a classical theory, based-like mechanics-on principles that are independent of the atomic constitution of matter. This book is unique among electromagnetic texts in its treatment of the precise manner in which electromagnetism is linked to mechanics and thermodynamics. Applications include electrostriction, piezoelectricity, ferromagnetism, superconductivity, thermoelectricity, magnetohydrodynamics, radiation from charged particles, electromagnetic wave propagation and guided waves. There are many worked examples of dynamical and thermal effects of electromagnetic fields, and of effects resulting from the motion of bodies.

  4. Electromagnetic compatibility design guideline for STADAN

    NASA Technical Reports Server (NTRS)

    Cowdell, R. B.; Hill, J. S.; Senn, J. C.; Shifman, J. C.; Skaggs, J. W.

    1971-01-01

    Procedures for achieving electromagnetic compatibility in electronic and electrical equipment for aerospace ground stations are investigated. The application of shielding theory to good design is treated and standards of good practice are outlined for bonding, grounding, wiring, and cabling. Some aspects of filter design are explained, and suggestions are given for the application of filters to electronic and electrical equipment.

  5. Advance in MEIC cooling studies

    SciTech Connect

    Zhang, Yuhong; Derbenev, Ya.; Douglas, D.; Hutton, A.; Kimber, A.; Li, R.; Nissen, E.; Tennant,; Zhang, H.

    2013-06-01

    Cooling of ion beams is essential for achieving a high luminosity for MEIC at Jefferson Lab. In this paper, we present the design concept of the electron cooling system for MEIC. In the design, two facilities are required for supporting a multi-staged cooling scheme; one is a 2 MeV DC cooler in the ion pre-booster; the other is a high electron energy (up to 55 MeV) ERL-circulator cooler in the collider ring. The simulation studies of beam dynamics in an ERL-circulator cooler are summarized and followed by a report on technology development for this cooler. We also discuss two proposed experiments for demonstrating high energy cooling with a bunched electron beam and the ERL-circulator cooler.

  6. Electromagnetic pulses bone healing booster

    NASA Astrophysics Data System (ADS)

    Sintea, S. R.; Pomazan, V. M.; Bica, D.; Grebenisan, D.; Bordea, N.

    2015-11-01

    Posttraumatic bone restoration triggered by the need to assist and stimulate compensatory bone growth in periodontal condition. Recent studies state that specific electromagnetic stimulation can boost the bone restoration, reaching up to 30% decrease in recovery time. Based on the existing data on the electromagnetic parameters, a digital electronic device is proposed for intra oral mounting and bone restoration stimulation in periodontal condition. The electrical signal is applied to an inductive mark that will create and impregnate magnetic field in diseased tissue. The device also monitors the status of the electromagnetic field. Controlled wave forms and pulse frequency signal at programmable intervals are obtained with optimized number of components and miniaturized using surface mounting devices (SMD) circuits and surface mounting technology (SMT), with enhanced protection against abnormal current growth, given the intra-oral environment. The system is powered by an autonomous power supply (battery), to limit the problems caused by powering medical equipment from the main power supply. Currently the device is used in clinical testing, in cycles of six up to twelve months. Basic principles for the electrical scheme and algorithms for pulse generation, pulse control, electromagnetic field control and automation of current monitoring are presented, together with the friendly user interface, suitable for medical data and patient monitoring.

  7. Electromagnetically driven dwarf tornados in turbulent convection

    NASA Astrophysics Data System (ADS)

    Kenjereš, Saša

    2011-01-01

    Motivated by the concept of interdependency of turbulent flow and electromagnetic fields inside the spiraling galaxies, we explored the possibilities of generating a localized Lorentz force that will produce a three-dimensional swirling flow in weakly conductive fluids. Multiple vortical flow patterns were generated by combining arrays of permanent magnets and electrodes with supplied dc current. This concept was numerically simulated and applied to affect natural convection flow, turbulence, and heat transfer inside a rectangular enclosure heated from below and cooled from above over a range of Rayleigh numbers (104<=Ra<=5×109). The large-eddy simulations revealed that for low- and intermediate-values of Ra, the heat transfer was increased more than five times when an electromagnetic forcing was activated. In contrast to the generally accepted view that electromagnetic forcing will suppress velocity fluctuations and will increase anisotropy of turbulence, we demonstrated that localized forcing can enhance turbulence isotropy of thermal convection compared to its neutral state.

  8. Nonlinear electromagnetic wave equations for superdense magnetized plasmas

    SciTech Connect

    Shukla, Nitin; Brodin, G.; Marklund, M.; Shukla, P. K.; Stenflo, L.

    2009-07-15

    By using the quantum hydrodynamic and Maxwell equations, we derive the generalized nonlinear electron magnetohydrodynamic, the generalized nonlinear Hall-MHD (HMHD), and the generalized nonlinear dust HMHD equations in a self-gravitating dense magnetoplasma. Our nonlinear equations include the self-gravitating, the electromagnetic, the quantum statistical electron pressure, as well as the quantum electron tunneling and electron spin forces. They are useful for investigating a number of wave phenomena including linear and nonlinear electromagnetic waves, as well as three-dimensional electromagnetic wave turbulence spectra and structures arising from mode coupling processes at nanoscales in dense quantum magnetoplasmas.

  9. Cool Sportswear

    NASA Technical Reports Server (NTRS)

    1982-01-01

    New athletic wear design based on the circulating liquid cooling system used in the astronaut's space suits, allows athletes to perform more strenuous activity without becoming overheated. Techni-Clothes gear incorporates packets containing a heat-absorbing gel that slips into an insulated pocket of the athletic garment and is positioned near parts of the body where heat transfer is most efficient. A gel packet is good for about one hour. Easily replaced from a supply of spares in an insulated container worn on the belt. The products, targeted primarily for runners and joggers and any other athlete whose performance may be affected by hot weather, include cooling headbands, wrist bands and running shorts with gel-pack pockets.

  10. Transient electromagnetic interference in substations

    SciTech Connect

    Wiggins, C.M.; Thomas, D.E.; Nickel, F.S.; Salas, T.M. ); Wright, S.E. )

    1994-10-01

    Electromagnetic interference levels on sensitive electronic equipment are quantified experimentally and theoretically in air and gas insulated substations of different voltages. Measurement techniques for recording interference voltages and currents and electric and magnetic fields are reviewed and actual interference data are summarized. Conducted and radiated interference coupling mechanisms and levels in substation control wiring are described using both measurement results and electromagnetic models validated against measurements. The nominal maximum field and control wire interference levels expected in the switchyard and inside the control house from switching operations, faults, and an average lightning strike are estimated using high frequency transient coupling models. Comparisons with standards are made and recommendations given concerning equipment shielding and surge protection.

  11. Electromagnetic structure of pion

    SciTech Connect

    Mello, Clayton S.; Cruz Filho, Jose P.; Da Silva, Edson O.; El-Bennich, Bruno; De Melo, J. P.; Filho, Victo S.

    2013-03-25

    In this work, we analyze the electromagnetic structure of the pion, an elementary particle composed by a quark-antiquark bound state, by considering the calculation of its electromagnetic radius and its electromagnetic form factor in low and intermediate energy range. Such observables are determined by means of a theoretical model that takes into account the constituent quark and antiquark of the pion, in the formalism of the light-front field theory. In particular, it is considered a nonsymmetrical vertex for such a model, in which we have calculated the electromagnetic form factor of the pion in an optimized way, by varying its regulator mass, so that we can obtain the best value for the pion electromagnetic radius when compared with the experimental one. The theoretical calculations are also compared with the most recent experimental data involving the pion electromagnetic form factor and the results show very good agreement.

  12. Electromagnetically Clean Solar Arrays

    NASA Technical Reports Server (NTRS)

    Stem, Theodore G.; Kenniston, Anthony E.

    2008-01-01

    The term 'electromagnetically clean solar array' ('EMCSA') refers to a panel that contains a planar array of solar photovoltaic cells and that, in comparison with a functionally equivalent solar-array panel of a type heretofore used on spacecraft, (1) exhibits less electromagnetic interferences to and from other nearby electrical and electronic equipment and (2) can be manufactured at lower cost. The reduction of electromagnetic interferences is effected through a combination of (1) electrically conductive, electrically grounded shielding and (2) reduction of areas of current loops (in order to reduce magnetic moments). The reduction of cost is effected by designing the array to be fabricated as a more nearly unitary structure, using fewer components and fewer process steps. Although EMCSAs were conceived primarily for use on spacecraft they are also potentially advantageous for terrestrial applications in which there are requirements to limit electromagnetic interference. In a conventional solar panel of the type meant to be supplanted by an EMCSA panel, the wiring is normally located on the back side, separated from the cells, thereby giving rise to current loops having significant areas and, consequently, significant magnetic moments. Current-loop geometries are chosen in an effort to balance opposing magnetic moments to limit far-0field magnetic interactions, but the relatively large distances separating current loops makes full cancellation of magnetic fields problematic. The panel is assembled from bare photovoltaic cells by means of multiple sensitive process steps that contribute significantly to cost, especially if electomagnetic cleanliness is desired. The steps include applying a cover glass and electrical-interconnect-cell (CIC) sub-assemble, connecting the CIC subassemblies into strings of series-connected cells, laying down and adhesively bonding the strings onto a panel structure that has been made in a separate multi-step process, and mounting the wiring on the back of the panel. Each step increases the potential for occurrence of latent defects, loss of process control, and attrition of components. An EMCSA panel includes an integral cover made from a transparent material. The silicone cover supplants the individual cover glasses on the cells and serves as an additional unitary structural support that offers the advantage, relative to glass, of the robust, forgiving nature of the silcone material. The cover contains pockets that hold the solar cells in place during the lamination process. The cover is coated with indium tin oxide to make its surface electrically conductive, so that it serves as a contiguous, electrically grounded shield over the entire panel surface. The cells are mounted in proximity to metallic printed wiring. The painted-wiring layer comprises metal-film traces on a sheet of Kapton (or equivalent) polyimide. The traces include contact pads on one side of the sheet for interconnecting the cells. Return leads are on the opposite side of the sheet, positioned to form the return currents substantially as mirror images of, and in proximity to, the cell sheet currents, thereby minimizing magnetic moments. The printed-wiring arrangement mimics the back-wiring arrangement of conventional solar arrays, but the current-loop areas and the resulting magnetic moments are much smaller because the return-current paths are much closer to the solar-cell sheet currents. The contact pads are prepared with solder fo electrical and mechanical bonding to the cells. The pocketed cover/shield, the solar cells, the printed-wiring layer, an electrical bonding agent, a mechanical-bonding agent, a composite structural front-side face sheet, an aluminum honeycomb core, and a composite back-side face sheet are all assembled, then contact pads are soldered to the cells and the agents are cured in a single lamination process.

  13. Phenomenology of the deuteron electromagnetic form factors

    SciTech Connect

    David Abbott; Abdellah Ahmidouch; H. Anklin; J. Arvieux; James P. Ball; Shelton Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; Jim Dunne; Lars Ewell; L. Eyraud; C. Furget; Michel Garcon; Ron Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; A. Honegger; J. Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; Pete Markowitz; Justin McIntyre; David Meekins; F. Merchez; Joseph Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; Liming Qin; Ronald Ransome; J.-S. R'eal; Philip Roos; Paul Rutt; Reyad Sawafta; Stepan Stepanyan; Raphael Tieulent; E. Tomasi-Gustafsson; William Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; Claude Williamson; Stephen Wood; Chen Yan; Jianguo Zhao; W. Zhao

    2000-02-25

    A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

  14. Phenomenology of the deuteron electromagnetic form factors

    SciTech Connect

    David Abbott; Abdellah Ahmidouch; H. Anklin; J. Arvieux; James P. Ball; Shelton Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; Jim Dunne; Lars Ewell; L. Eyraud; C. Furget; Michel Garcon; Ron Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; A. Honegger; J. Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; Pete Markowitz; Justin McIntyre; David Meekins; F. Merchez; Joseph Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; Liming Qin; Ronald Ransome; J.-S. R'eal; Philip Roos; Paul Rutt; Reyad Sawafta; Stepan Stepanyan; Raphael Tieulent; E. Tomasi-Gustafsson; William Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; Claude Williamson; Stephen Wood; Chen Yan; Jianguo Zhao; W. Zhao

    2000-04-01

    A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

  15. Compton Sources of Electromagnetic Radiation

    SciTech Connect

    Geoffrey Krafft,Gerd Priebe

    2011-01-01

    When a relativistic electron beam interacts with a high-field laser beam, intense and highly collimated electromagnetic radiation will be generated through Compton scattering. Through relativistic upshifting and the relativistic Doppler effect, highly energetic polarized photons are radiated along the electron beam motion when the electrons interact with the laser light. For example, X-ray radiation can be obtained when optical lasers are scattered from electrons of tens-of-MeV beam energy. Because of the desirable properties of the radiation produced, many groups around the world have been designing, building, and utilizing Compton sources for a wide variety of purposes. In this review article, we discuss the generation and properties of the scattered radiation, the types of Compton source devices that have been constructed to date, and the prospects of radiation sources of this general type. Due to the possibilities of producing hard electromagnetic radiation in a device that is small compared to the alternative storage ring sources, it is foreseen that large numbers of such sources may be constructed in the future.

  16. REACTOR COOLING

    DOEpatents

    Quackenbush, C.F.

    1959-09-29

    A nuclear reactor with provisions for selectively cooling the fuel elements is described. The reactor has a plurality of tubes extending throughout. Cylindrical fuel elements are disposed within the tubes and the coolant flows through the tubes and around the fuel elements. The fuel elements within the central portion of the reactor are provided with roughened surfaces of material. The fuel elements in the end portions of the tubes within the reactor are provlded with low conduction jackets and the fuel elements in the region between the central portion and the end portions are provided with smooth surfaces of high heat conduction material.

  17. Supercooling effects in Cu-10 wt pct Co alloys solidified at different cooling rates

    NASA Technical Reports Server (NTRS)

    Munitz, A.; Elder-Randall, S. P.; Abbaschian, R.

    1992-01-01

    Electromagnetic levitation and electron beam surface melting were employed to study the effects of supercooling and cooling rate on the solidification of Cu-10 wt pct Co alloys. Two major effects were observed in the supercooled alloys: the nucleation of a metastable copper-rich phase which contains 13 wt pct to 20 wt pct Co in samples supercooled between 105 and 150 K and liquid phase separation which occurs in samples supercooled 150 K or more. The microstructure of the electron beam melted surfaces consisted of very fine spheres which were similar to those of the sample supercooled more than 150 K but with a refined microstructure. The results indicate that a dynamic bulk supercooling of 150 K may exist in the molten pool during the solidification of electron beam melted surfaces.

  18. Electromagnetic compatibility overview

    NASA Astrophysics Data System (ADS)

    Davis, K. C.

    1980-07-01

    An assessment of the electromagnetic compatibility impact of the Satellite Power System is discussed. The discussion is divided into two parts: determination of the emission expected from SPS including their spatial and spectral distributions, and evaluation of the impact of such emissions on electromagnetic systems including considerations of means for mitigating effects.

  19. Introducing Electromagnetic Field Momentum

    ERIC Educational Resources Information Center

    Hu, Ben Yu-Kuang

    2012-01-01

    I describe an elementary way of introducing electromagnetic field momentum. By considering a system of a long solenoid and line charge, the dependence of the field momentum on the electric and magnetic fields can be deduced. I obtain the electromagnetic angular momentum for a point charge and magnetic monopole pair partially through dimensional

  20. Introducing Electromagnetic Field Momentum

    ERIC Educational Resources Information Center

    Hu, Ben Yu-Kuang

    2012-01-01

    I describe an elementary way of introducing electromagnetic field momentum. By considering a system of a long solenoid and line charge, the dependence of the field momentum on the electric and magnetic fields can be deduced. I obtain the electromagnetic angular momentum for a point charge and magnetic monopole pair partially through dimensional…