Sample records for electromagnetics electron cooling

  1. ElectronicsCooling

    NSDL National Science Digital Library

    An important concern facing electronics designers is heat dissipation. Especially in laptop computers and server farms, overheating can be a major problem. ElectronicsCooling is a free, quarterly publication that provides "practical information to the reader that relates to cooling of today's electronics." Every article since the magazine's debut in 1995 can be viewed from this site. Common topics are packaging, thermal design, and technical data related to many types of electronics. Contributions to ElectronicsCooling are generally from industry and academia.

  2. Coherent Electron Cooling

    SciTech Connect

    Litvinenko, Vladimir N. [Brookhaven National Laboratory, Upton, Long Island, New York (United States); Derbenev, Yaroslav S. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia (United States)

    2009-03-20

    Cooling intense high-energy hadron beams poses a major challenge for modern accelerator physics. The synchrotron radiation emitted from such beams is feeble; even in the Large Hadron Collider (LHC) operating with 7 TeV protons, the longitudinal damping time is about 13 hours. None of the traditional cooling methods seem able to cool LHC-class protons beams. In this Letter, we present a novel method of coherent electron cooling based on a high-gain free-electron laser (FEL). This technique could be critical for reaching high luminosities in hadron and electron-hadron colliders.

  3. 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.

  4. 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.

  5. Electromagnetic electron temperature anisotropy instabilities

    NASA Technical Reports Server (NTRS)

    Gary, S. P.; Madland, C. D.

    1985-01-01

    This paper considers electromagnetic Vlasov instabilities driven by electron temperature anisotropies in a homogeneous, nonrelativistic magnetized plasma. Numerical solutions of the full linear dispersion equation for bi-Maxwellian distribution functions and instabilities propagating parallel to the magnetic field are presented. Parametric dependences of the maximum growth rates of the electron fire hose and whistler anisotropy instabilities are given.

  6. Electromagnetic electron temperature anisotropy instabilities

    NASA Astrophysics Data System (ADS)

    Gary, S. P.; Madland, C. D.

    1985-08-01

    This paper considers electromagnetic Vlasov instabilities driven by electron temperature anisotropies in a homogeneous, nonrelativistic magnetized plasma. Numerical solutions of the full linear dispersion equation for bi-Maxwellian distribution functions and instabilities propagating parallel to the magnetic field are presented. Parametric dependences of the maximum growth rates of the electron fire hose and whistler anisotropy instabilities are given.

  7. Power electronics cooling apparatus

    DOEpatents

    Sanger, Philip Albert (Monroeville, PA); Lindberg, Frank A. (Baltimore, MD); Garcen, Walter (Glen Burnie, MD)

    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.

  8. Direct cooled power electronics substrate

    DOEpatents

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

  9. Electron Cooling for RHIC V. Parkhomchuk

    E-print Network

    C-A/AP/47 April 2001 Electron Cooling for RHIC V. Parkhomchuk Budker Institute of Nuclear Physics I Upton, NY 11973 #12;C-A/AP/47 April 2001 Electron Cooling for RHIC V. Parkhomchuk Budker Institute National Laboratory Upton, NY 11973 #12;ELECTRON COOLING FOR RHIC Review of the Principles of Electron

  10. 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.

  11. Improved cooling of electromagnetics by directed airflow

    NASA Astrophysics Data System (ADS)

    Fain, Adam Matthew

    The transformers in aircraft power conversion are often very heavy and represent a significant fuel or range penalty. Being thermally sized, improved cooling methods would allow downsizing and thereby reduced weight. Since the conductive paths in these metal "dense" devices are good, the controlling thermal resistance is typically the convective coefficient. The goal of this study was to optimize the convective air cooling across transformers by parametrically testing candidate shroud geometries to minimize average and hot spot surface temperatures with minimal fan power. A test set up was constructed that included a low velocity wind tunnel, fan, temperature and pressure sensors, DAQ system, and film heaters as well as the actual transformers. Experimental results from a low velocity wind tunnel were well predicted by CFD modeling, providing confidence in continued shroud development with only CFD or experimentally. Curved or bent types of shapes proved to be the most efficient shroud configurations in terms of maximizing heat transfer while reducing the energy requirement to achieve the desired level of cooling.

  12. Advanced optical concepts for electron cooling

    NASA Astrophysics Data System (ADS)

    Derbenev, Ya. S.

    2000-02-01

    The results of explorations of non-traditional solutions of beam transport which could raise the electron cooling rates and efficiency are presented. The proposed optical elements, methods, and conceptual designs are summarized in the following. (1) Magnetized electron beam acceleration and transport with discontinuous solenoid to provide matching between the electron gun and solenoid of the cooling section. These concepts allow the possibility to design and build economical, high beam quality accelerators for electron cooling over a wide energy range, up to that suited for hadron colliders. (2) A special beam adapter (skew quadrupole block) to transform between a magnetized and a flat beam state. This element meets a variety of uses in electron cooling trends. (3) Injectors with ring-shaped cathodes and resonance concentrators of hollow beams involving (optionally) beam adapters. (4) An isochronous (at no RF) electron recirculator ring with a solenoid in the cooling section and beam adapters. (5) Electron storage rings incorporating strong wigglers, solenoid in cooling section with beam adapters, non-coupled focusing outside the cooling section, and (optionally) a strong longitudinal optics for beam compression in wigglers. (6) Hadron beam optics in the cooling section with non-extended beams and dispersion introduced in order to maximize the transverse cooling rate. (7) Low-energy cooling with matched electron and hadron beams. (8) Low-energy cooling with hollow beams.

  13. 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.

  14. MEIC Electron Cooling Simulation Using Betacool

    SciTech Connect

    Zhang, He [JLAB; Zhang, Yuhong [JLAB

    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.

  15. 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,; 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.

  16. FOUR-QUADRANT POWER SUPPLIES FOR STEERING ELECTROMAGNETS FOR ELECTRON-POSITRON COLLIDERS

    E-print Network

    Kozak, Victor R.

    FOUR-QUADRANT POWER SUPPLIES FOR STEERING ELECTROMAGNETS FOR ELECTRON-POSITRON COLLIDERS O. Belikov with application of up-to-date components. INTRODUCTION The quality of operation of electron-positron collider. Table 1: Detached dipole correctors of electron-positron colliders are mainly cooled with air and power

  17. Sympathetic Electromagnetically-Induced-Transparency Laser Cooling of Motional Modes in an Ion Chain

    NASA Astrophysics Data System (ADS)

    Lin, Y.; Gaebler, J. P.; Tan, T. R.; Bowler, R.; Jost, J. D.; Leibfried, D.; Wineland, D. J.

    2013-04-01

    We use electromagnetically-induced-transparency laser cooling to cool motional modes of a linear ion chain. As a demonstration, we apply electromagnetically-induced-transparency cooling on Mg+24 ions to cool the axial modes of a Be+9-Mg+24 ion pair and a Be+9-Mg+24-Mg+24-Be+9 ion chain, thereby sympathetically cooling the Be+9 ions. Compared to previous implementations of conventional Raman sideband cooling, we achieve approximately an order-of-magnitude reduction in the duration required to cool the modes to near the ground state and significant reduction in required laser intensity.

  18. ELECTRON COOLING FOR THE THERAPY ACCELERATOR COMPLEX

    Microsoft Academic Search

    V. V. Parkhomchuk; V. B. Reva; A. V. Bubley; V. M. Panasyuk

    2009-01-01

    Institute of Nuclear Physics (BINP, Novosibirsk) is engaged in R&D of the new therapy accelerator system based on the electron cooling. The electron cooling is used for the ion beam accumulation in process of repeated multi turn injection into the main ring from the fast cycling booster synchrotron. After acceleration of the carbon ions up to 200-400 MeV\\/u the electron

  19. 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.

  20. 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.

  1. 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.

  2. Electromagnetic energy propagation in power electronic converters: toward future electromagnetic integration

    Microsoft Academic Search

    JAN ABRAHAM FERREIRA; J. DAAN VAN WYK

    2001-01-01

    Historically, it came about that the analysis and design of the power electronic converter center around currents and voltages in the circuits. During the last decade, the electromagnetic character of power electronic converters became more important due to the noise that the switches generate, and electromagnetic interference (EMI) and electromagnetic compatibility (EMC) standards have been put in place to control

  3. 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

  4. Power electronics substrate for direct substrate cooling

    DOEpatents

    Le, Khiet (Mission Viejo, CA); Ward, Terence G. (Redondo Beach, CA); Mann, Brooks S. (Redondo Beach, CA); Yankoski, Edward P. (Corona, CA); Smith, Gregory S. (Woodland Hills, CA)

    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.

  5. Methods and apparatus for cooling electronics

    SciTech Connect

    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.

  6. 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.

  7. Single Pass Electron Cooling Simulations for MEIC

    SciTech Connect

    Bell, G. I. [Tech-X Corp.; Pogorelov, I. V. [Tech-X Corp.; Schwartz, B. T. [Tech-X Corp.; Zhang, Yuhong [JLAB; Zhang, He [JLAB

    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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Analytical studies of coherent electron cooling

    SciTech Connect

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

    2009-05-04

    Under certain assumptions and simplifications, we studied a few physics processes of Coherent Electron Cooling using analytical approach. In the modulation process, the effect due to merging the ion beam with the electron beam is studied under single kick approximation. In the free electron laser (FEL) amplifier, we studied the amplification of the electron density modulation using 1D analytical approach. Both the electron charge density and the phase space density are derived in the frequency domain. The solutions are then transformed into the space domain through Fast Fourier Transformation (FFT).

  13. Simulation of electron cooling dynamic ( December 16, 2003)

    E-print Network

    of formulas for the friction force and IBS to simulate cooling dynamics (cooling+ibs+...) for RHIC. · SimCool code: Uses VP empiric formula for friction force and gas-diffusion formula for IBS to simulate electron cooling dynamics. #12;SimCool 1. Cooling ­ individual particles 2. IBS ­ i.p. but based on rms rates

  14. 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.

  15. Cavity cooling of a trapped atom using Electromagnetically-Induced Transparency

    E-print Network

    Marc Bienert; Giovanna Morigi

    2011-12-01

    A cooling scheme for trapped atoms is proposed, which combines cavity-enhanced scattering and electromagnetically induced transparency. The cooling dynamics exploits a three-photon resonance, which combines laser and cavity excitations. It is shown that relatively fast ground-state cooling can be achieved in the Lamb-Dicke regime and for large cooperativity. Efficient ground-state cooling is found for parameters of ongoing experiments.

  16. 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.

  17. 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.

  18. Electronic cooling design and test validation

    NASA Astrophysics Data System (ADS)

    Murtha, W. B.

    1983-07-01

    An analytical computer model has been used to design a counterflow air-cooled heat exchanger according to the cooling, structural and geometric requirements of a U.S. Navy shipboard electronics cabinet, emphasizing high reliability performance through the maintenance of electronic component junction temperatures lower than 110 C. Environmental testing of the design obtained has verified that the analytical predictions were conservative. Model correlation to the test data furnishes an upgraded capability for the evaluation of tactical effects, and has established a two-orders of magnitude growth potential for increased electronics capabilities through enhanced heat dissipation. Electronics cabinets of this type are destined for use with Vertical Launching System-type combatant vessel magazines.

  19. Cooling an electron gas using quantum dot based electronic refrigeration

    E-print Network

    Prance, Jonathan Robert

    2009-10-13

    Cooling an electron gas using quantum dot based electronic refrigeration Jonathan Robert Prance August 28, 2009 Downing College, University of Cambridge A thesis submitted for the degree of Doctor of Philosophy Preface The work presented... dots. Conventionally, low temperature measurements of 2DEGs are made by cooling the sample to 1.5 K with liquid Helium-4, to 300 mK with liquid Helium-3, or even down to a few mK using a dilution refrigerator. However, at lower temperatures the electron...

  20. 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.

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

    SciTech Connect

    Kroc, T.K.; Burov, A.V.; Bolshakov, T.B.; Shemyakin, A.; /Fermilab; 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.

  2. 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.

  3. 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.

  4. Electron Cooling Performance at IMP Facility

    E-print Network

    Yang Xiaodong

    2011-10-10

    The ion beam of 58Ni19+ with the energy of 6.39MeV/u was accumulated in the main ring of HIRFL-CSR with the help of electron cooling. The related angle between ion and electron beams in the horizontal and vertical planes was intentionally created by the steering coils in the cooling section after maximized the accumulated ion beam in the ring. The radial electron intensity distribution was changed by the ratio of potentials of grid electrode and anode of the electron gun, the different electron beam profiles were formed from solid to hollow in the experiments. In these conditions, the maximum accumulated ion beam intensity in the 10 seconds was measured, the lifetime of ion beam was measured, simultaneously the momentum spread of the ion beam varying with particle number was measured during the ion beam decay, furthermore, and the power coefficient was derived from these data. In additional, the momentum spread in the case of constant particle number was plotted with the angle and electron beam profile. The oscillation and shift of the central frequency of the ion beam were observed during the experiments. The upgrade and improvement in the CSRm cooler and the progress in the CSRe cooler were presented. These results were useful to attempt the crystal beam forming investigation in the CSR.

  5. Evaluation of Cooling Solutions for Outdoor Electronics

    E-print Network

    Mahendra Wankhede; V. Khaire; A. Goswami; S. D. Mahajan

    2008-01-07

    The thermal management of an outdoor electronic enclosure can be quite challenging due to the additional thermal load from the sun and the requirement of having an air-sealed enclosure. It is essential to consider the effect of solar heating loads in the design process; otherwise, it can shorten the life expectancy of the electronic product or lead to catastrophic failure. In this paper we analyze and compare the effectiveness of different cooling techniques used for outdoor electronics. Various cooling techniques were compared like special coatings and paints on the outer surface, radiation shields, double-walled vented enclosures, fans for internal air circulation and air-to-air heat exchangers. A highly simplified, typical outdoor system was selected for this study measuring approximately 300x300x400 mm (WxLxH). Solar radiation was incident on 3 sides of the enclosure. There were 8 equally spaced PCBs inside the enclosure dissipating 12.5W each uniformly (100 watts total). A computational fluid dynamics (CFD) model of the system was built and analyzed. This was followed by building a mock-up of the system and conducting experiments to validate the CFD model. It was found that some of the simplest cooling techniques like white oil paint on the outer surface can significantly reduce the impact of solar loads. Adding internal circulation fans can also be very effective. Using air-to-air heat exchangers was found to be the most effective solution although it is more complex and costly.

  6. Electron Cooling for RHIC* Ilan Ben-Zvi

    E-print Network

    Electron Cooling for RHIC* Ilan Ben-Zvi Collider Accelerator Department and National Synchrotron the designation RHIC II. One important component of the RHIC II upgrade is electron cooling of RHIC gold ion beams initially at the development of the electron cooling conceptual design, resolution of technical issues

  7. Collisional Cooling of Pure Electron Plasmas W. Bertsche

    E-print Network

    Fajans, Joel

    Collisional Cooling of Pure Electron Plasmas Using CO2 W. Bertsche and J. Fajans Physics Department, U. C. Berkeley Abstract. Inelastic collisions with CO2 buffer gas cool a pure electron gas in a Penning-Malmberg trap at low magnetic fields. 0.6 eV electrons are cooled by down to 30% of their original

  8. Electron Cooling Studies for RHIC-II October 16, 2006 Electron Cooling studies for RHIC-II

    E-print Network

    Electron Cooling Studies for RHIC-II October 16, 2006 Electron Cooling studies for RHIC-II I.A.1 magnetized cooling I.A.1.3 Parameters of electron cooler I.A.1.4 Suppression of recombination with undulators: experiments vs theory I.A.3.3 IBS for ion beam distribution under electron cooling I.A.4 Recombination I.A.4

  9. Adiabatic cooling of solar wind electrons

    NASA Technical Reports Server (NTRS)

    Sandbaek, Ornulf; Leer, Egil

    1992-01-01

    In thermally driven winds emanating from regions in the solar corona with base electron densities of n0 not less than 10 exp 8/cu cm, a substantial fraction of the heat conductive flux from the base is transfered into flow energy by the pressure gradient force. The adiabatic cooling of the electrons causes the electron temperature profile to fall off more rapidly than in heat conduction dominated flows. Alfven waves of solar origin, accelerating the basically thermally driven solar wind, lead to an increased mass flux and enhanced adiabatic cooling. The reduction in electron temperature may be significant also in the subsonic region of the flow and lead to a moderate increase of solar wind mass flux with increasing Alfven wave amplitude. In the solar wind model presented here the Alfven wave energy flux per unit mass is larger than that in models where the temperature in the subsonic flow is not reduced by the wave, and consequently the asymptotic flow speed is higher.

  10. Stimulated electromagnetic emission near electron cyclotron harmonics in the ionosphere

    Microsoft Academic Search

    T. B. Leyser; B. Thide; H. Derblom; A. Hedberg; B. Lundborg; P. Stubbe; H. Kopka; M. Rietveld

    1989-01-01

    Observations of electromagnetic emission stimulated by a high-frequency radio wave injected into the ionosphere from a ground-based powerful transmitter operated near harmonics of the ionospheric electron cyclotron frequency are reported. Significant changes in the spectrum of the stimulated electromagnetic radiation were obtained as the injected frequency was varied in small steps around these harmonics. The experimental results are attributed to

  11. Electron Cooling Dynamics progress update ( December 15, 2003)

    E-print Network

    Electron Cooling Dynamics progress update ( December 15, 2003) A. Fedotov #12;Goals of the meeting cooling dynamics issues we would like to get input on our present studies and understanding. 2. We would and benchmarking: Vorpal, SimCool and BetaCool this morning 3. We started to study friction force with the Vorpal

  12. Electron Cooling of the Relativistic Heavy Ion Collider

    E-print Network

    Electron Cooling of the Relativistic Heavy Ion Collider: Overview Ilan Ben-Zvi Collider-Accelerator Department's Machine Advisory Committee January 2006 #12;Motivation The motivation for electron coolingRHIC are on the DOE's 20 years facilities plan. RHIC luminosity decay (3.5 hours) #12;What is special about cooling

  13. Thermal management of high power dissipation electronic packages: from air cooling to liquid cooling

    Microsoft Academic Search

    H. Y. Zhang; D. Pinjala; Poi-Siong Teo

    2003-01-01

    Performance-driven electronic packaging demands for thermal solutions of high power dissipation such as enhanced air cooling or, alternatively, liquid cooling technologies. This paper reports the characterization of air-cooled vapor chamber heat sink (VCHS) and liquid cooled heat sinks (LCHS) for electronic packages with a targeted power dissipation of 140W. The test vehicle flip chip plastic BGA package (FC-PBGA) involves a

  14. 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.

  15. Microbunched electron cooling for high-energy hadron beams.

    PubMed

    Ratner, D

    2013-08-23

    Electron and stochastic cooling are proven methods for cooling low-energy hadron beams, but at present there is no way of cooling hadrons as they near the TeV scale. In the 1980s, Derbenev suggested that electron instabilities, such as free-electron lasers, could create collective space charge fields strong enough to correct the hadron energies. This Letter presents a variation on Derbenev's electron cooling scheme using the microbunching instability as the amplifier. The large bandwidth of the instability allows for faster cooling of high-density beams. A simple analytical model illustrates the cooling mechanism, and simulations show cooling rates for realistic parameters of the Large Hadron Collider. PMID:24010445

  16. Electromagnetic Tagging for Electronic Music Interfaces

    Microsoft Academic Search

    Joseph A. Paradiso; Laurel S. Pardue; Kai-Yuh Hsiao; Ari Y. Benbasat

    2003-01-01

    This paper describes the development of a musical interface based on electromagnetic tagging technology, where an ensemble of passively tagged objects is identified and tracked in real time when placed in the vicinity of a reader. As the system is able to identify and update the state of many (30 or more) tags simultaneously, they can be used together in

  17. 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.

  18. Electron distribution of the degenerate electron gas of a plasma in a strong electromagnetic field

    NASA Astrophysics Data System (ADS)

    Ablekov, V. K.; Babaev, Iu. N.; Frolov, A. M.

    1980-01-01

    The paper determines the electron energy distribution function for the degenerate electron gas of a dense plasma in an intense electromagnetic field. The analysis is applicable to conditions in solid state plasmas.

  19. Electronics Cooling Using a Self-Contained, Sub-Cooled Pumped Liquid System

    Microsoft Academic Search

    W. John Bilski; Gregg Baldassarre; Matt Connors; Jerry Toth; Kevin L. Wert

    2008-01-01

    Electronic thermal packaging design continues to look for novel solutions for enhancing the performance of microelectronic cooling solutions. Driven by increasing thermal performance requirements, particularly in densely packaged militarized electronic systems and other high density or extreme use products, thermal designers are showing that to achieve the necessary cooling, combinations of existing technologies may offer further enhancement than has already

  20. 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.

  1. Electron Cooling of the Relativistic Heavy Ion Collider

    E-print Network

    / simulations ERL Linac cavity Guns Laser, photocathodes Beam dynamics Electron cooling Friction, IBS Dynamics, photocathode and laser. Rama Calaga, graduate student, SRF cavity, ERL. Xiangyun Chang, graduate student, beam Hershcovitch, plasma physics and beam dump. Gary McIntyre, Electron Cooling Project Engineer. Christoph Montag

  2. Progress with FEL-based coherent electron cooling

    SciTech Connect

    Litvinenko,V.; Ben-Zvi, I.; Blaskiewicz, M.; Hao, Y.; Kayran, D.; Pozdeyev, E.; Wang, G.; Bell, G.; Bruhwiler, D.; Sobol, A.; Shevchenko, O.; Vinokurov, N.A.; Derbenev, Y.; Reiche, S.

    2008-08-24

    Cooling intense high-energy hadron beams remains a major challenge for accelerator physics. Synchrotron radiation is too feeble, while efficiency of two other cooling methods falls rapidly either at high bunch intensities (i.e. stochastic cooling of protons) or at high energies (i.e. e-cooling). The possibility of coherent electron cooling, based on high-gain FEL and ERL, was presented at last FEL conference [1]. This scheme promises significant increases in luminosities of modern high-energy hadron and electron-hadron colliders, such as LHC and eRHIC. In this paper we report progress made in the past year on the development of this scheme of coherent electron cooling (CeC), results of analytical and numerical evaluation of the concept as well our prediction for LHC and RHIC. We also present layout for proof-of-principle experiment at RHIC using our R&D ERL which is under construction.

  3. 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.

  4. Absorption of electromagnetic radiation by semimetal electrons

    SciTech Connect

    Sigachev, A.F.

    1986-06-01

    This paper investigates cyclotron photon resonance in textured bismuth where the electron energy in the conduction band is determined by an expression (presented), using perturbation theory methods. It is shown that the electron dispersion law, not being quadratic, results in spin splitting of the resonance peaks.

  5. 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.

  6. Generation of Microwave Free-Electron Laser Radiation Using Sheet Electron Beam and Planar Electromagnet Wiggler

    Microsoft Academic Search

    K. K. Jain; K. K. Mohandas; A. V. Ravikumar

    1999-01-01

    An experimental study of sheet electron beam propagation through a planar electromagnet and generation of microwave radiation by free-electron laser action has been carried out. The space charge dominated sheet electron beam of energy 100-200 keV, current 50-150 A, and pulsewidth of 100-150 ns was propagated through a 20-period planar electromagnet wiggler. Significant enhancement in the beam transmission through the

  7. Generation of Microwave Free-Electron Laser Radiation Using Sheet Electron Beam and Planar Electromagnet Wiggler

    Microsoft Academic Search

    K. K. Jain

    2002-01-01

    An experimental study of sheet electron beam propagation through a planar electromagnet and generation of microwave radiation by free-electron laser action has been carried out. The space charge dominated sheet electron beam of energy 100-200 keV, current 50-150 A, and pulsewidth of 100-150 ns was propagated through a 20-period planar electromagnet wiggler. Significant enhancement in the beam transmission through the

  8. Generation of microwave free-electron laser radiation using sheet electron beam and planar electromagnetic wiggler

    Microsoft Academic Search

    A. V. Ravi Kumar; K. K. Mohandas; K. K. Jain

    1998-01-01

    An experimental study of sheet electron beam propagation through a planar electromagnetic wiggler and generation of microwave radiation by free-electron laser action has been carried out. The space charge dominated sheet electron beam of energy ~100-200 keV, current 50-150 A, and pulsewidth of 100-150 ns was propagated through a 20-period planar electromagnetic wiggler. Significant enhancement in the beam transmission through

  9. The interaction of electromagnetic radiation with one-electron atoms

    E-print Network

    Landstreet, John D.

    The interaction of electromagnetic radiation with one-electron atoms January 21, 2002 1 Introduction We examine the interactions of radiation with a hydrogen-like atom as a simple ex- ample by passing radiation), spontaneous emission (radiation without any external stimulus), and the continuum

  10. Electromagnetic solitary pulses in a magnetized electron-positron plasma

    SciTech Connect

    Shukla, P. K. [RUB International Chair, International Centre for Advanced Studies in Physical Sciences, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Eliasson, B. [Institut fuer Theoretische Physik, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Stenflo, L. [Department of Physics, Linkoeping University, SE-58183 Linkoeping (Sweden)

    2011-03-15

    A theory for large amplitude compressional electromagnetic solitary pulses in a magnetized electron-positron (e-p) plasma is presented. The pulses, which propagate perpendicular to the external magnetic field, are associated with the compression of the plasma density and the wave magnetic field. Here the solitary wave magnetic field pressure provides the restoring force, while the inertia comes from the equal mass electrons and positrons. The solitary pulses are formed due to a balance between the compressional wave dispersion arising from the curl of the inertial forces in Faraday's law and the nonlinearities associated with the divergence of the electron and positron fluxes, the nonlinear Lorentz forces, the advection of the e-p fluids, and the nonlinear plasma current densities. The compressional solitary pulses can exist in a well-defined speed range above the Alfven speed. They can be associated with localized electromagnetic field excitations in magnetized laboratory and space plasmas composed of electrons and positrons.

  11. Electromagnetic solitary pulses in a magnetized electron-positron plasma.

    PubMed

    Shukla, P K; Eliasson, B; Stenflo, L

    2011-09-01

    A theory for large amplitude compressional electromagnetic solitary pulses in a magnetized electron-positron (e-p) plasma is presented. The pulses, which propagate perpendicular to the external magnetic field, are associated with the compression of the plasma density and the wave magnetic field. Here the solitary wave magnetic field pressure provides the restoring force, while the inertia comes from the equal mass electrons and positrons. The solitary pulses are formed due to a balance between the compressional wave dispersion arising from the curl of the inertial forces in Faraday's law and the nonlinearities associated with the divergence of the electron and positron fluxes, the nonlinear Lorentz forces, the advection of the e-p fluids, and the nonlinear plasma current densities. The compressional solitary pulses can exist in a well-defined speed range above the Alfvn speed. They can be associated with localized electromagnetic field excitations in magnetized laboratory and space plasmas composed of electrons and positrons. PMID:22060541

  12. Free-electron lasers with electromagnetic standing wave wigglers

    Microsoft Academic Search

    T. M. TRAN; BRUCE G. DANLY; J. S. Wurtele

    1987-01-01

    A detailed analysis of the electromagnetic standing wave wiggler for free-electron lasers (FEL's) is conducted for both circular and linear wiggler polarizations, following a single-particle approach. After determination of the unperturbed electron orbits in the wiggler field, the single-particle spontaneous emission spectrum and subsequently the gain in the low gain Compton regime (using the Einstein coefficient method) are explicitly calculated.

  13. Attractors and chaos of electron dynamics in electromagnetic standing wave

    E-print Network

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

    2014-01-01

    The radiation reaction radically influences the electron motion in an electromagnetic standing wave formed by two super-intense counter-propagating laser pulses. Depending on the laser intensity and wavelength, either classical or quantum mode of radiation reaction prevail, or both are strong. When radiation reaction dominates, electron motion evolves to limit cycles and strange attractors. This creates a new framework for high energy physics experiments on an interaction of energetic charged particle beams and colliding super-intense laser pulses.

  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. ISEF 2009 -XIV International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering

    E-print Network

    Paris-Sud XI, Université de

    in Mechatronics, Electrical and Electronic Engineering, Arras : France (2009)" #12;ISEF 2009 - XIV International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering Arras, FranceISEF 2009 - XIV International Symposium on Electromagnetic Fields in Mechatronics, Electrical

  16. Ground-state cooling for a trapped atom using cavity-induced double electromagnetically induced transparency.

    PubMed

    Yi, Zhen; Gu, Wen-ju; Li, Gao-xiang

    2013-02-11

    We propose a cooling scheme for a trapped atom using the phenomenon of cavity-induced double electromagnetically induced transparency (EIT), where the atom comprising of four levels in tripod configuration is confined inside a high-finesse optical cavity. By exploiting one cavity-induced EIT, which involves one cavity photon and two laser photons, carrier transition can be eliminated due to the quantum destructive interference of excitation paths. Heating process originated from blue-sideband transition mediated by cavity field can also be prohibited due to the destructive quantum interference with the additional transition between the additional ground state and the excited state. As a consequence, the trapped atom can be cooled to the motional ground state in the leading order of the Lamb-Dicke parameters. In addition, the cooling rate is of the same order of magnitude as that obtained in the cavity-induced single EIT scheme. PMID:23481803

  17. 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.

  18. 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.

  19. Classical ``Dressing'' of a Free Electron in a Plane Electromagnetic Wave Kirk T. McDonald

    E-print Network

    McDonald, Kirk

    Classical ``Dressing'' of a Free Electron in a Plane Electromagnetic Wave Kirk T. McDonald Joseph densities of the fields of a free electron in a plane electromagnetic wave include interference terms of a free electron in a electromagnetic wave is one of the most commonly discussed topics in classical

  20. Classical "Dressing" of a Free Electron in a Plane Electromagnetic Wave Kirk T. McDonald

    E-print Network

    McDonald, Kirk

    Classical "Dressing" of a Free Electron in a Plane Electromagnetic Wave Kirk T. McDonald Joseph densities of the fields of a free electron in a plane electromagnetic wave include interference terms of a free electron in a electromagnetic wave is one of the most commonly discussed topics in classical

  1. An electromagnetically focused electron beam line source

    Microsoft Academic Search

    Munawar Iqbal; Khalid Masood; Mohammad Rafiq; Maqbool A. Chaudhary; Fazal-E.-Aleem

    2003-01-01

    A directly heated thermionic electron beam source was constructed. A tungsten wire of length 140 mm with diameter 0.9 mm was used as a cathode. An emission current of 5000 mA was achieved at an input heating power of 600 W. Cathode to anode distance of 6 mm with acceleration voltage of 10 kV was used. A uniform external magnetic

  2. Cooling force on ions in a magnetized electron plasma

    NASA Astrophysics Data System (ADS)

    Nersisyan, Hrachya B.; Zwicknagel, Gnter

    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.

  3. Cooling electrons by magnetic-field tuning of Andreev reflection.

    PubMed

    Giazotto, Francesco; Taddei, Fabio; Governale, Michele; Castellana, Carlo; Fazio, Rosario; Beltram, Fabio

    2006-11-10

    A solid-state cooling principle based on magnetic-field-driven tunable suppression of Andreev reflection in superconductor/two-dimensional electron gas nanostructures is proposed. This cooling mechanism can lead to very large heat fluxes per channel up to 10;{4} times greater than currently achieved with superconducting tunnel junctions. This efficacy and its availability in a two-dimensional electron system make this method of particular relevance for the implementation of quantum nanostructures operating at cryogenic temperatures. PMID:17155652

  4. 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.

  5. 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.

  6. 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.

  7. Raman Sideband Cooling of Two-Valence-Electron Fermionic Atoms

    NASA Astrophysics Data System (ADS)

    Li, Guo-Hui; Xu, Xin-Ye

    2011-06-01

    We propose a method for laser cooling two-valence-electron fermionic atoms. Our protocol employs resolved-sideband cooling on the stimulated Raman transition between the two magnetic sublevels (m = F and m = F - 1) of the ground state with total angular momentum F. The optical pumping from m = F - 1 to 1P1 are used to decouple atoms in the m = F - 1 state. We calculate the Raman coupling generated by an engineered optical lattice. The result shows that it is possible to laser cool the two-valence-electron fermionic atoms to the ground state. The atoms in the ground state provide a new system for quantum optics.

  8. 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.

  9. Partially ferromagnetic electromagnet for trapping and cooling neutral atoms to quantum degeneracy

    SciTech Connect

    Fauquembergue, M.; Riou, J-F.; Guerin, W.; Rangwala, S.; Moron, F.; Villing, A.; Le Coq, Y.; Bouyer, P.; Aspect, A.; Lecrivain, M. [Groupe d'Optique Atomique, Laboratoire Charles Fabry de l'Institut d'Optique, Unite Mixte de Recherche (UMR) 8501 du Centre National de la Recherche Scientifique (CNRS), Batiment 503 Campus Universitaire d'Orsay, 91403 Orsay Cedex (France); Systemes et Applications des Technologies de l'Information et de Energie - SATIE, Laboratoire de l'Ecole Normale Superieure de Cachan, Unite Mixte de Recherche (UMR) 8029 du Centre National de la Recherche Scientifique (CNRS), 61, Avenue du President Wilson, 94235 Cachan Cedex (France)

    2005-10-15

    We have developed a compact partially ferromagnetic electromagnet to produce an Ioffe-Pritchard trap for neutral atoms. Our structure permits strong magnetic confinement with low power consumption. Compared to the previous iron-core electromagnet [B. Desruelle, V. Boyer, P. Bouyer, G. Birkl, M. Lecrivain, F. Alves, C. Westbrook, and A. Aspect, Eur. Phys. J. D 1, 255 (1998)], it allows for easy compensation of remnant fields and very high stability, along with cost-effective realization and compactness. We describe and characterize our apparatus and demonstrate trapping and cooling of {sup 87}Rb atoms to quantum degeneracy. Pure Bose-Einstein condensates containing 10{sup 6} atoms are routinely realized on a half-minute cycle. In addition we test the stability of the magnetic trap by producing atom lasers.

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

    SciTech Connect

    Genes, Claudiu; Ritsch, Helmut [Institute for Theoretical Physics, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria); Drewsen, Michael; Dantan, Aurelien [QUANTOP, Danish National Research Foundation Center for Quantum Optics, Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

    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.

  11. Electromagnetic Phenomena in Superconducting Magnet for Fusion Facility -Pool-Cooled Superconducting Coil-

    NASA Astrophysics Data System (ADS)

    Imagawa, Shinsaku

    The features of superconducting coils for nuclear fusion devices include large size, high field, and high current density. A large conductor is needed for such a large coil to suppress the voltage increase. Since the ability of pool-cooling becomes relatively less with the increase of conductor size, new technologies are necessary to achieve both sufficient mechanical strength and cryogenic stability with high current density. A composite conductor of the 20 kA class was developed for the LHD helical coils. The conductor consists of a pure aluminum stabilizer, a copper sheath, and NbTi/Cu strands. New electromagnetic phenomena, which are Hall current and slow current diffusion into the stabilizer, deteriorate the cryogenic stability. The mechanism and countermeasures are described. Furthermore, a perspective on pool-cooled coils is discussed.

  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. Direct Liquid Cooling for Electronic Henry Coles and Steve Greenberg

    E-print Network

    LBNL-6641E Direct Liquid Cooling for Electronic Equipment Henry Coles and Steve Greenberg consulting and modeling to support the energy-efficiency analysis. Thanks to Vali Sorell, V for this project. #12;ii ABSTRACT This report documents a demonstration of an electronic

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

    Microsoft Academic Search

    Amin Taghavi; Mahdi Esmaeilzadeh; Mohammad S. Fallah

    2010-01-01

    Chaotic behavior of an electron motion in combined backward propagating electromagnetic wiggler and ion-channel electrostatic fields is studied. The Poincar 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

  15. 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.

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

    SciTech Connect

    Nguyen, J. H. V.; Odom, B. [Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208 (United States)

    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. 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.

  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. Electromagnetic waves and electron anisotropies downstream of supercritical interplanetary shocks

    E-print Network

    Wilson, L B; Szabo, A; Breneman, A; Cattell, C A; Goetz, K; Kellogg, P J; Kersten, K; Kasper, J C; Maruca, B A; Pulupa, M

    2012-01-01

    We present waveform observations of electromagnetic lower hybrid and whistler waves with f_ci 1.01. Thus, the whistler mode waves appear to be driven by a heat flux instability and cause perpendicular heating of the halo electrons. The lower hybrid waves show a much weaker correlation between \\partialB and normalized heat flux magnitude and are often observed near magnetic field gradients. A third type of event shows fluctuations consistent with a mixture of both lower hybrid and whistler mode waves. These results suggest that whistler waves may indeed be regulating the electron heat flux and the halo temperature anisotropy, which is important for theories and simulations of electron distribution evolution from the sun to the earth.

  20. 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.

  1. Stability of arbitrary electron velocity distribution functions to electromagnetic modes

    SciTech Connect

    Tzoufras, M.; Ren, C.; Tsung, F. S.; Tonge, J. W.; Mori, W. B.; Fiore, M.; Fonseca, R. A.; Silva, L. O. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Departments of Mechanical Engineering and Physics and Astronomy, and Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Department of Electrical Engineering and Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); GoLP/Centro de Fisica dos Plasmas, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal)

    2007-06-15

    The stability of general electron distribution functions to purely electromagnetic modes is considered, so as to generalize the well-known stability analysis for bi-Gaussian distribution functions. The expansion of an arbitrary nonrelativistic distribution function into a modified version of Hermite-Gaussian modes yields the dispersion relation for electromagnetic modes in a compact form that depends on the coefficients of the expansion as well as the well-known plasma dispersion function and its derivatives. The coefficients of the expansion that enter the dispersion relation depend only on the zeroth and second moments from the direction of high temperature. The general dispersion relation is solved analytically for the frequency in the low anisotropy (kinetic) limit. Purely imaginary solutions can be found for distribution functions symmetric in the direction of the wavenumber. If, in addition to being symmetric, the distribution function is separable, the only quantity from the high-temperature direction that enters the equation for the frequency of the electromagnetic wave is the variance.

  2. 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.

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

    PubMed

    Trueba, Alfredo; Garca, Sergio; Otero, Flix 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

  4. 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.

  5. High density electronic packaging module with improved cooling assembly

    NASA Technical Reports Server (NTRS)

    Martin, J. H.

    1971-01-01

    Cold plate increases heat transfer within high density electronic module. Tapered pins improve heat transfer process by providing larger surface pressure with increased planar area. Cooling technique increases thermal contact where planar area is limited, interface pressure increases the heat transfer coefficient.

  6. 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.; Rhrich, 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.

  7. 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.

  8. 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.

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

    SciTech Connect

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

    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

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

    SciTech Connect

    Taghavi, Amin; Esmaeilzadeh, Mahdi; Fallah, Mohammad S. [Department of Physics, Iran University of Science and Technology, Narmak, Tehran 16844 (Iran, Islamic Republic of)

    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.

  11. ELECTROMAGNETIC THERMAL INSTABILITY WITH MOMENTUM AND ENERGY EXCHANGE BETWEEN ELECTRONS AND IONS IN GALAXY CLUSTERS

    SciTech Connect

    Nekrasov, Anatoly K., E-mail: nekrassov@t-online.de, E-mail: anekrasov@ifz.ru [Institute of Physics of the Earth, Russian Academy of Sciences, 123995 Moscow (Russian Federation)

    2011-10-01

    Thermal instability in an electron-ion magnetized plasma, which is relevant in the intragalactic medium of galaxy clusters, solar corona, and other two-component plasma objects, is investigated. We apply the multicomponent plasma approach where the dynamics of all species are considered separately through electric field perturbations. General expressions for the dynamical variables obtained in this paper can be applied over a wide range of astrophysical and laboratory plasmas also containing neutrals and dust grains. We assume that background temperatures of electrons and ions are different and include the energy exchange in thermal equations for electrons and ions along with the collisional momentum exchange in equations of motion. We take into account the dependence of collision frequency on density and temperature perturbations. The cooling-heating functions are taken for both electrons and ions. A condensation mode of thermal instability has been studied in the fast sound speed limit. We derive a new dispersion relation including different electron and ion cooling-heating functions and other effects mentioned above and find its simple solutions for growth rates in limiting cases. We show that the perturbations have an electromagnetic nature and demonstrate the crucial role of the electric field perturbation along the background magnetic field in the fast sound speed limit. We find that at the conditions under consideration, condensation must occur along the magnetic field while the transverse scale sizes can be both larger and smaller than the longitudinal ones. The results obtained can be useful for interpretating observations of dense cold regions in astrophysical objects.

  12. Cooled CCD camera with tapered fibre optics for electron microscopy

    NASA Astrophysics Data System (ADS)

    Faruqi, A. R.; Andrews, H. N.

    1997-02-01

    A CCD camera for use in electron microscopy, with 1286 1152, 37 ?m pixels and an input aperture of 60 mm diameter, is described in this paper. An attempt is made to optimise the phosphor resolution for 120 keV electrons using Monte-Carlo simulation methods. Incident electrons are converted to visible light in a polycrystalline phosphor (P43) deposited on tapered fibre optics and imaged on to a cooled slow-scan CCD which is controlled from a Sun sparc-station, running under a Unix platform, through a VME-based drive and read-out electronics system. The camera is attached to a Philips CM12 microscope and is used mainly for recording electron-diffraction patterns from two-dimensinally ordered protein arrays. Data can be displayed rapidly on the Sun monitor and can also be transferred for further analysis to a Dec Alpha computer via Ethernet for application of various image-processing programs.

  13. ISEF 2007 -XIV International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering

    E-print Network

    Boyer, Edmond

    International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, ArrasISEF 2007 - XIV International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering Arras, France, September 10-12, 2009 Validation of a 3D decoupled magnetodynamic

  14. ISEF 2009 -XIV International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering

    E-print Network

    Paris-Sud XI, Université de

    on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, Arras : France (2009)" #12;ISEFISEF 2009 - XIV International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering Arras, France, September 10-12, 2009 OPTIMAL DESIGN OF A WOUND ROTOR SYNCHRONOUS

  15. 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.

  16. 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.

  17. 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%).

  18. Reduced-Density-Matrix Descriptions for Coherent Electromagnetic Interactions in Quantized Many-Electron Systems

    Microsoft Academic Search

    Verne Jacobs

    2004-01-01

    Reduced-density-matrix descriptions are developed for linear and non-linear electromagnetic interactions in quantized electronic systems, including atomic systems and semiconductors materials (bulk solids and heterostructures). Environmental decoherence processes are treated on a formally equal footing with coherent electron-electron and electromagnetic interactions. Frequency-domain (resolvent-operator) and time-domain (equation-of-motion) formulations are self-consistently developed. A preliminary semi-classical description is developed to examine different electronic-state representations.

  19. Electron trajectories and gain for an electromagnetic wiggler with ion-channel guiding

    SciTech Connect

    Esmaeilzadeh, Mahdi; Ghafouri, Vahid; Taghavi, Amin; Namvar, Esmaeil [Department of Physics, Iran University of Science and Technology, Narmak, Tehran 16844 (Iran, Islamic Republic of); Department of Physics, Tarbiat Moallem University, 49 Dr Mofatteh Avenu, Tehran 15614 (Iran, Islamic Republic of)

    2006-04-15

    A theory is developed for a free-electron laser with electromagnetic wiggler and ion-channel guiding. The electron trajectories due to a large amplitude backward propagating electromagnetic wiggler and an ion-channel electrostatic field are obtained and the stability of orbits is discussed. Then the gain equation describing the interaction between an electron and the radiation field is derived in the low-gain-per-pass limit. The results of a numerical study of electron orbits and gain are presented and discussed. It is shown that the maximum gain obtained in an electromagnetic wiggler is about twice the maximum gain obtained in a magnetostatic wiggler.

  20. 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.

  1. Cryogenic heat pipe for cooling high temperature superconductors with application to Electromagnetic Formation Flight Satellites

    E-print Network

    Kwon, Daniel W., 1980-

    2009-01-01

    An emerging method of propellant-less formation flight propulsion is the use of electromagnets coupled with reaction wheels. This technique is called Electromagnetic Formation Flight (EMFF). In order to create a large ...

  2. 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.

  3. Principles of gyrotron powered electromagnetic wigglers for free-electron lasers

    Microsoft Academic Search

    B. G. Danly; G. Bekefi; R. C. Davidson; R. J. Temkin; T. M. Tran; J. S. Wurtele

    1987-01-01

    The operation of free-electron lasers (FEL's) with axial electron beams and high-power electromagnetic wiggler fields such as those produced by high-power gyrotrons is discussed. The use of short wavelength electromagnetic wigglers in waveguides and resonant cavities can significantly reduce required electron beam voltages, resulting in compact FEL's. Gain calculations in the low- and high-gain Compton regime are presented, including the

  4. Influence of electron evaporative cooling on ultracold plasma expansion

    SciTech Connect

    Wilson, Truman; Chen, Wei-Ting; Roberts, Jacob [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)] [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)

    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.

  5. Effects of Electromagnetic Shielding Cases for Semiconductor-type Electronic Personal Dosimeters on Preventing Electromagnetic Interference

    Microsoft Academic Search

    Shizuhiko Deji; Shigeki Ito; Saze Takuya; Kazuyuki Mori; Kunihide Nishizawa

    2005-01-01

    (SEPDs)caused by high frequency electromagnetic fields emitted from a digital cellular telephone (cell phone)and a card reader of access control system were analyzed. The cases were handcrafted by using cloth of activated carbon fiber, polyester film laminated metal, and two kinds of metal netting. Five kinds of SEPDs put in the cases were exposed to the high frequency electromagnetic fields

  6. 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., E-mail: borisov@phys.msu.ru [Moscow State University (Russian Federation)

    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.

  7. Measurement of Electromagnetic Radiation Emitted during Rapid Intramolecular Electron Transfer

    E-print Network

    , photosynthesis, artificial photosynthesis, redox chemistry, photography, xerog- raphy, and other processes all the electromagnetic (EM) waveform broadcast by the charge-transfer process itself. Intermolecular and intramo- lecular

  8. Electromagnets

    NSDL National Science Digital Library

    This is an activity about the properties of electromagnets, which is a crucial underpinning for understanding how magnetic fields are generated in nature, in the surface of the Sun, and in the interior of Earth. Learners will create an electromagnet by letting an electric current flow through a wire to generate a magnetic field, which is then detected using a compass. This activity requires a thin insulated wire, pencil, battery, compass and paper clips. This is Activity 2 of the Magnetism and Electromagnetism teachers guide.

  9. 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.

  10. Electromagnets

    NSDL National Science Digital Library

    Michael Horton

    2009-05-30

    In this investigation, students will construct electromagnets and test to see which variables make them stronger. Although elementary and middle school teachers are expected to have done this activity with their classes, teachers of younger students often

  11. ISEF 2007 -XIII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering

    E-print Network

    Paris-Sud XI, Université de

    ISEF 2007 - XIII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering Prague, Czech Republic, September 13-15, 2007 OPTIMISATION OF A DRIVE SYSTEM AND ITS manuscript, published in "ISEF 2007 - XIII International Symposium on Electromagnetic Fields in Mechatronics

  12. Electromagnetic Interference with Electronic Medical Equipment Induced by Automatic Conveyance Systems

    Microsoft Academic Search

    Eisuke Hanada; Yoshiaki Watanabe; Yoshiaki Nose

    2000-01-01

    Electromagnetic interference (EMI) with electronic medical equipment induced by automatic conveyance systems is estimated. We measured the electric intensities of electromagnetic waves transmitted by three self-controlled electric truck systems. We also observed EMI with an infusion pump and a syringe pump set 1 m from the rail. The maximum electric field intensity was observed at the supplied current frequency in

  13. Analysis of Microwave Electromagnetic Compatibility in Shielding Electronic System

    Microsoft Academic Search

    Song Hang; Rao Yu-ping; Shao Ying; Zhou Dong-fang; Hu Tao; Niu Zhong-xia

    2008-01-01

    An electromagnetic topology model used to analyse the High Power Microwave (HPM) effect on the different electrical components is presented. The model, whose foundation is linear coupling of aperture, emphasizes on the basic concept of electromagnetic topology, the abstract in the system analysis and two parameters: the polarization of electric field and the frequency of HPM. The algorithm of graph

  14. 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.

  15. 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.

  16. ISEF 2005 -XII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering

    E-print Network

    ISEF 2005 - XII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering Baiona, Spain, September 15-17, 2005 INTEGRATED MAGNETICS DESIGN FOR HF-LINK POWER

  17. Production of flickering aurora and field-aligned electron flux by electromagnetic ion cyclotron waves

    Microsoft Academic Search

    M. Temerin; J. McFadden; M. Boehm; C. W. Carlson; W. Lotko

    1986-01-01

    Recent observations have suggested that flickering aurora is produced by a modulation of the field-aligned component of the electron flux within an auroral arc. It is proposed that a portion of the field-aligned electrons are of ionospheric origin and that these electrons are accelerated and their flux modulated by electromagnetic ion cyclotron waves that occur below the main acceleration region

  18. Relativistic electron pitch-angle scattering by electromagnetic ion cyclotron waves during geomagnetic storms

    Microsoft Academic Search

    Danny Summers; Richard M. Thorne

    2003-01-01

    During magnetic storms, relativistic electrons execute nearly circular orbits about the Earth and traverse a spatially confined zone within the duskside plasmapause where electromagnetic ion cyclotron (EMIC) waves are preferentially excited. We examine the mechanism of electron pitch-angle diffusion by gyroresonant interaction with EMIC waves as a cause of relativistic electron precipitation loss from the outer radiation belt. Detailed calculations

  19. 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.

  20. Quantum-limited velocity readout and quantum feedback cooling of a trapped ion via electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Rabl, P.; Steixner, V.; Zoller, P.

    2005-10-01

    We discuss continuous observation of the momentum of a single atom by employing the high velocity sensitivity of the index of refraction in a driven ? -system based on electromagnetically induced transparency. In the ideal limit of unit collection efficiency this provides a quantum-limited measurement with minimal backaction on the atomic motion. A feedback loop, which drives the atom with a force proportional to measured signal, provides a cooling mechanism for the atomic motion. We derive the master equation which describes the feedback cooling and show that in the Lamb-Dicke limit the steady state energies are close to the ground state, limited only by the photon collection efficiency. Outside of the Lamb-Dicke regime the predicted temperatures are well below the Doppler limit.

  1. Electromagnets

    NSDL National Science Digital Library

    VU Bioengineering RET Program,

    In this activity, the students will complete the grand challenge and design an electromagnet to separate steel from aluminum for the recycler. In order to do this, students compare the induced magnetic field of an electric current with the magnetic field of a permanent magnet and must make the former look like the latter. They discover that looping the current produces the desired effect and find ways to further strengthen the magnetic field.

  2. An Electronic Water-Saving Integrated System for Toilet Bowl Based on Electromagnetic Valve Controlling

    Microsoft Academic Search

    Tingjun Wang; Li Gu

    2009-01-01

    This electronic controlling double-joined-valve system is a new type of electronic water-saving integrated system for toilet bowl according to the demand of domestic toilet water-saving. The electronic water-saving integrated system are consists of an electron control system, electromagnetic double joined valve, domestic wastewater reuse device, feedwater pipeline system, sewage drainage pipeline system and toilet bowl. Its structure assembly and working

  3. Two-phase refrigerant flow instability analysis and active control in transient electronics cooling systems

    E-print Network

    Peles, Yoav

    Two-phase refrigerant flow instability analysis and active control in transient electronics cooling Pressure-drop oscillation Refrigeration system Two-phase cooling Active control Transient heat load a b s t r a c t Two-loop refrigeration systems are being explored for two-phase cooling of ultra high power

  4. 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.

  5. 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.

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

    SciTech Connect

    Timofeev, I. V.; Annenkov, V. V. [Budker Institute of Nuclear Physics SB RAS and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    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.

  8. Possible Electromagnetic Interference with Electronic Medical Equipment by Radio Waves Coming from Outside the Hospital

    Microsoft Academic Search

    Eisuke Hanada; Kenji Kodama; Kyoko Takano; Yoshiaki Watanabe; Yoshiaki Nose

    2001-01-01

    Electromagnetic interference (EMI) with electronic medical equipment by radio waves from mobile telephone handsets has been reported and is currently receiving wide attention. The possibility of EMI with electronic medical equipment by radio waves coming into the hospital has also been pointed out. But so far, there are no reports measuring the frequency distribution of electric field intensity induced by

  9. 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.

  10. Long term exposure electromagnetic effects on discrete analog and digital electronic devices

    Microsoft Academic Search

    G. J. Erickson; A. J. Pesta

    1998-01-01

    A determination is made of the effects of long term exposure of analog and digital electronic devices to electromagnetic (EM) fields in the radio frequency range of 700 MHz to 18 GHz. Test results are used to determine short term and long term reliability of electronic devices and systems when exposed to EM environments. This study involves design and fabrication

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    Previous studies of electron-phonon interaction in impure graphene have found that disorder can give rise to an enhancement of electronic cooling at high temperatures. We investigate the effect of lattice vacancy in both mono- and bilayer graphene and observe an order of magnitude suppression of electronic cooling at low temperatures compared with clean graphene. 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 photodetector devices.

  12. 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.

  13. 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 [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India)] [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Dey, Indranuj [Department of Advanced Energy Engineering Science, Kyushu University, Kasuga Kouen 6-1, Kasuga City 816-8580 (Japan)] [Department of Advanced Energy Engineering Science, Kyushu University, Kasuga Kouen 6-1, Kasuga City 816-8580 (Japan); Roy Chowdhury, Krishanu [Max Planck Institute for the Physics of Complex System, Dresden 01187 (Germany)] [Max Planck Institute for the Physics of Complex System, Dresden 01187 (Germany)

    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.

  14. Energy linearity and resolution of the ATLAS electromagnetic barrel calorimeter in an electron test-beam

    Microsoft Academic Search

    M. Aharrouche; Jacques Colas; L. Di Ciaccio; M. El Kacimi; O. Gaumer; M. Gouanre; D. Goujdami; R. Lafaye; S. Laplace; C. Le Maner; L. Neukermans; P. Perrodo; L. Poggioli; D. Prieur; H. Przysiezniak; G. Sauvage; F. Tarrade; I. Wingerter-Seez; R. Zitoun; F. Lanni; H. Ma; S. Rajagopalan; S. Rescia; H. Takai; A. Belymam; D. Benchekroun; M. Hakimi; A. Hoummada; E. Barberio; Y. S. Gao; L. Lu; R. Stroynowski; Martin Aleksa; J. B. Hansen; T. Carli; I. Efthymiopoulos; P. Fassnacht; F. Follin; F. Gianotti; L. Hervas; W. Lampl; J. Collot; J. Y. Hostachy; F. Ledroit-Guillon; P. Martin; F. Ohlsson-Malek; S. Saboumazrag; M. Leltchouk; J. A. Parsons; M. Seman; S. Simion; D. Banfi; L. Carminati; D. Cavalli; G. Costa; M. Delmastro; M. Fanti; L. Mandelli; M. Mazzanti; G. F. Tartarelli; C. Bourdarios; L. Fayard; D. Fournier; G. Graziani; S. Hassani; L. Iconomidou-Fayard; M. Kado; M. Lechowski; M. Lelas; G. Parrour; P. Puzo; D. Rousseau; R. Sacco; L. Serin; G. Unal; D. Zerwas; A. Camard; D. Lacour; B. Laforge; I. Nikolic-Audit; Ph. Schwemling; H. Ghazlane; R. C. El Moursli; A Idrissi Fakhr-Eddine; M. Boonekamp; N. Kerschen; B. Mansouli; P. Meyer; J. Schwindling; B. Lund-Jensen; Y. Tayalati

    2006-01-01

    A module of the ATLAS electromagnetic barrel liquid argon calorimeter was exposed to the CERN electron test-beam at the H8 beam line upgraded for precision momentum measurement. The available energies of the electron beam ranged from 10 to 245GeV. The electron beam impinged at one point corresponding to a pseudo-rapidity of ?=0.687 and an azimuthal angle of ?=0.28 in the

  15. Verification of electromagnetic fluid-kinetic hybrid electron model in global gyrokinetic particle simulation

    SciTech Connect

    Holod, I.; Lin, Z. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)

    2013-03-15

    The fluid-kinetic hybrid electron model is verified in global gyrokinetic particle simulation of linear electromagnetic drift-Alfvenic instabilities in tokamak. In particular, we have recovered the {beta}-stabilization of the ion temperature gradient mode, transition to collisionless trapped electron mode, and the onset of kinetic ballooning mode as {beta}{sub e} (ratio of electron kinetic pressure to magnetic pressure) increases.

  16. 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 [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    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)

  17. Optimal Fan Arrangement for Electronic Equipment with Multi-Fan CoolingSystem including Air Cooled Heat Sink with Fan

    Microsoft Academic Search

    Hitoshi Matsushima; Shuichi Terakado; Ichirou Asano

    2009-01-01

    Parametric study is conducted for optimizing the fan arrangement of the electronic equipment with several fans inthe equipment. Those fans are cooling for central processing unit (CPU), for power supply unit (PSU), and for the other devices in the equipment (system exhaust fan). We have used the Taguchi method of the experimental design for finding the optimal arrangement of those

  18. Kinetic theory of the electron bounce instability in two dimensional current sheetsFull electromagnetic treatment

    SciTech Connect

    Tur, A.; Fruit, G.; Louarn, P. [Institut de Recherche en Astrophysique et Plantologie (IRAP), CNRS UMR5277/Universit Paul Sabatier, Toulouse (France)] [Institut de Recherche en Astrophysique et Plantologie (IRAP), CNRS UMR5277/Universit Paul Sabatier, Toulouse (France); Yanovsky, V. [Institute for Single Crystals, National Academy of Sciences of Ukraine, Kharkov 61001 (Ukraine)] [Institute for Single Crystals, National Academy of Sciences of Ukraine, Kharkov 61001 (Ukraine)

    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 ??=?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 instabilityelectromagnetic electron-bounce instabilitymay explain fast and global scale destabilization of current sheets as required to describe substorm phenomena.

  19. 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.

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

    NASA Astrophysics Data System (ADS)

    Yu, Haining; Du, Jiulin

    2014-11-01

    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.

  1. 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.

  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. An Electronic Control Unit for Reducing Contact Bounce in Electromagnetic Contactors

    Microsoft Academic Search

    2008-01-01

    With the increasing concern on reliability and life span of electromagnetic contactors, manufacturers are now providing devices equipped with electronic control units, in an effort to reduce problems associated with contact bounce, such as contact wear, excessive heating, contact welding, etc. The addition of a control unit, however, brings increased costs both in the development and production of this new

  4. An optimization system with parallel processing for reducing electromagnetic interference on electronic control unit

    Microsoft Academic Search

    Yuji Okazaki; Takanori Uno; Hideki Asai

    2009-01-01

    In this paper, we propose an optimization system with parallel processing for reducing electromagnetic interference (EMI) on electronic control unit (ECU). We adopt simulated annealing (SA), genetic algorithm (GA) and taboo search (TS) to seek optimal solutions, and a SPICE-like circuit simulator to analyze common-mode current. Therefore, the proposed system can determine the adequate combinations of the parasitic inductance and

  5. Realization of a relativistic mirror: Electromagnetic backscattering from the front of a magnetized relativistic electron beam

    Microsoft Academic Search

    V. L. Granatstein; P. Sprangle; R. K. Parker; J. Pasour; M. Herndon; S. P. Schlesinger; J. L. Seftor

    1976-01-01

    An intense relativistic electron beam has been injected into a cylindrical drift tube containing a counterstreaming electromagnetic wave (f sub i = 9.3 GHz and P sub i = 170 kW). Within a narrow range of axial magnetic field centered at 5 kG, a reflected wave at f sub s approximately 40 GHz was generated by the interaction of the

  6. The polarization of a final electron in the field of intensive electromagnetic wave

    E-print Network

    E. M. Bol'shedvorsky; S. I. Polityko

    1999-04-12

    The polarization properties of the Compton effect in the field of a circularly polarized electromagnetic wave are discussed. In the case of nonlinear Compton effect the behavior of spin is analyzed. The transformation of the longitudinal polarization in the transverse polarization is showed. We obtained the total formulas describing the polarization of the final electron in the nonlinear case.

  7. The excitation of coherent electromagnetic radiation in plasma waveguides by relativistic electron beams

    Microsoft Academic Search

    B. I. Aronov; L. S. Bogdankevich; A. A. Rukhadze

    1976-01-01

    A theoretical analysis is presented of the interaction between a monoenergetic relativistic electron beam and a bounded plasma and the conditions for the generation of electromagnetic radiation in a single mode by such a system are derived. Two specific geometries are considered: (a) a metallic waveguide of radius R, completely filled with plasma which is penetrated by a beam of

  8. 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.

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

    SciTech Connect

    Wang, J. [Physics Department, Fudan University, Shanghai 210433 (China); Science and Technology on Plasma Physics Laboratory, Mianyang 621900 (China); 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., E-mail: yqgu@caep.ac.cn [Science and Technology on Plasma Physics Laboratory, Mianyang 621900 (China); Cao, L. H. [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    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.

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

    SciTech Connect

    Komar, A.; Pokol, G. I. [Department of Nuclear Techniques, Budapest University of Technology and Economics, Association EURATOM, H-1111 Budapest (Hungary); Fueloep, T. [Department of Applied Physics, Nuclear Engineering, Chalmers University of Technology and Euratom-VR Association, Goeteborg (Sweden)

    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.

  11. Low frequency electromagnetic oscillations in dense degenerate electron-positron pair plasma, with and without ions

    SciTech Connect

    Khan, S. A. [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Ayub, M. K. [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Pohang University of Science and Technology (POSTECH), Pohang, Gyunbuk 790-784 (Korea, Republic of); Ahmad, Ali [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)

    2012-10-15

    Quantum plasma oscillations are studied in a strongly magnetized, ultra-dense plasma with degenerate electrons and positrons. The dispersive role of electron and positron quantum effects on low frequency (in comparison to electron cyclotron frequency) shear electromagnetic wave is investigated by employing hydrodynamic formulation. In the presence of ions, the density balance changes, and the electromagnetic wave (with frequency lower than the ion cyclotron frequency) is shown to couple with electrostatic ion mode under certain conditions. For such low frequency waves, it is also seen that the contribution of electron and positron degeneracy pressure is dominant as compared to their diffraction effects. The results are analyzed numerically for illustrative purpose pointing out their relevance to the dense laboratory (e.g., super-intense laser-dense matter interactions) and astrophysical plasmas.

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

    SciTech Connect

    Zacharias, Michael; Schlickeiser, Reinhard, E-mail: mz@tp4.rub.de, E-mail: rsch@tp4.rub.de [Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

    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.

  13. Experimental demonstration of an electromagnetically pumped free-electron laser with a cyclotron-harmonic idler

    Microsoft Academic Search

    R. A. Kehs; Y. Carmel; V. L. Granatstein; W. W. Destler

    1988-01-01

    A three-wave, free-electron laser was operated with a powerful 8.4-GHz electromagnetic ''pump'' wave replacing the usual magnetostatic wiggler. The presence of a uniform axial magnetic field B produced cyclotron-harmonic ''idler'' waves. Peaks in the emission spectrum corresponding to cyclotron harmonics were observed covering a frequency range from 16.5 to 130 GHz. The frequency spectrum of this novel free-electron laser mechanism

  14. Absorption of electromagnetic energy by slow electrons under scattering from Coulomb centers

    Microsoft Academic Search

    V. P. Krainov

    2001-01-01

    Simple analytical expressions are obtained for the rate of the inverse stimulated bremsstrahlung absorption under electron\\u000a scattering from a Coulomb center with charge Z in the presence of the electromagnetic field. The initial and final values of electron energy are assumed to be small compared\\u000a to the Rydberg energy Z\\u000a 2 (atomic units are used throughout). Single-photon processes of absorption

  15. Assessment of power electronic inverter cooling requirements for a rear-axle drive

    Microsoft Academic Search

    Jonas Ottosson

    2011-01-01

    The work presented in this paper is focused on determining the cooling requirement and its effect on the reliability of a power electronic inverter used in a rear-axle drive for a hybrid car. The cooling requirements are determined through electro-thermal simulations. Several comparative electro-thermal simulations are carried out for different levels of cooling, i.e. convection coefficients, power module integration and

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

    SciTech Connect

    Bandurkin, I. V.; Kuzikov, S. V. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Savilov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod (Russian Federation)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    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.

  18. Package cooling designs for a dual-chip electronic package with one high power chip

    Microsoft Academic Search

    Amilcar Arvelo; Hilton Toy; K. Sikka; A. Tai; H. Longworth; Wei Zou; J. Coffin

    2004-01-01

    Dual-chip microelectronic packages (DCP) with one high power chip are being increasingly encountered in computer and other electronic systems where a common chip carrier, whether a ceramic or an organic laminate, has a central processing unit (CPU) accompanied by a memory chip. In this study, package cooling designs are developed and presented for cooling two product applications of the DCP,

  19. Energy efficient hotspot-targeted embedded liquid cooling of electronics Chander Shekhar Sharma a

    E-print Network

    Daraio, Chiara

    into the backside of a chip (embedded liquid cooling or ELC architecture). We adopt an experimentally validatedEnergy efficient hotspot-targeted embedded liquid cooling of electronics Chander Shekhar Sharma. Microchannel throttling zones distribute flow optimally without any external control. Design is optimized

  20. Thermohydraulic Dynamics and Fuzzy Coordination Control of a Microchannel Cooling Network for Space Electronics

    Microsoft Academic Search

    Yun-Ze Li; Kok-Meng Lee

    2011-01-01

    This paper presents the dynamic model, analysis, and fuzzy control of a microchannel-heat-exchanger (MHE) space cooling network for dissipating exhaust heat of onboard electronic components inside spacecraft to the outer space environment. Along with a method for modeling a nonlinear fluid resistance network, a detailed analysis of flow rate changes and temperature transients of the MHE cooling network is given,

  1. Steady-state electron trajectories and growth rate in electromagnetically pumped free-electron laser with specific nonuniform magnetic field

    SciTech Connect

    Mehdian, H.; Jafari, S.; Hasanbeigi, A. [Department of Physics and Institute for Plasma Research, Tarbiat Moallem University, Tehran 15614 (Iran, Islamic Republic of)

    2008-07-15

    A theory of the dispersion relation for electromagnetically pumped free-electron laser in the presence of a special tapered axial guide magnetic field is presented. An analysis of the steady-state electron trajectories is obtained by solving the equations of motion. Next an eleventh-degree polynomial equation for electromagnetic and space-charge wave is derived. Numerical solution of the polynomial equation of the dispersion relation yield the complex wave number as a function of the frequency of the waves. These results are used to illustrate the dependence of growth rate curves on the axial guide field frequency. It is found that the tapered guide field shifts electron trajectories and enhances the growth rate in the comparison of employing uniform axial magnetic field, without needing a strong guide magnetic field.

  2. Laser Compton Cooling of Relativistic Electron and Positron Beams and Pair Plasmas

    NASA Astrophysics Data System (ADS)

    Liang, Edison; Dahlstrom, Erin

    2010-11-01

    With the advance of high energy intense lasers, it becomes conceivable to use photons to slow down relativistic electron and positron beams, or rapidly cool a relativistic electron-positron pair plasma. Here we present results from the Monte Carlo simulations of the Compton cooling of relativistic electrons and positrons using intense lasers of one micron wavelength. We find that several hundred kJ to a MJ of laser energy is sufficient to Compton cool multi-MeV electrons/positrons down to keV energies and below. We also explore the use of resonant Compton cooling in a strong magnetic field (100 MG and above). Preliminary results using Doppler shifted laser light look promising.

  3. REVIEWS OF TOPICAL PROBLEMS: New directions in the theory of electron cooling

    NASA Astrophysics Data System (ADS)

    Men'shikov, L. I.

    2008-07-01

    The theory of electron cooling of ions and positrons is reviewed. Formulas describing the retarding force of ions in an electron beam with an 'oblate' velocity distribution, which is typical for electron cooling, are considered for arbitrary intensities of a magnetic field. Considered for positrons are the cases of intermediate and strong magnetic fields, which are of the greatest practical interest. The friction force and the components of the positron velocity diffusion tensor are calculated. Also discussed is the relaxation of positrons in their electron cooling in positron storage rings and their transition to the stationary distribution. The stationary velocity distribution function for positrons is shown to practically coincide in this case with that for electrons. The feasibility of lowering the transverse electron temperature is analyzed, which is required for decreasing the positron spread in momentum.

  4. Microcontrolled electronic gear for HID lamps comparisons with electromagnetic ballast

    Microsoft Academic Search

    Mhrcio A. CO; Cassius Z. Rezende; Domingos S. L. Simonetti; Josk L. F. Vieira

    2002-01-01

    This paper presents an electronic control gear for high intensity discharge (HID) lamps that operates with a low frequency current inverter to drive the lamp, a DC-DC buck converter to control the power and lamp current, and a power factor pre-regulator based on a discontinuous conduction mode boost converter. The signals of all power stages are provided by a dedicated

  5. 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.

  6. 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.

    2014-12-01

    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.

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

    SciTech Connect

    Abbasi, H. [Faculty of Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Hakimi Pajouh, H. [Department of Physics, Alzahra University, Tehran 19834 (Iran, Islamic Republic of)

    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.

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

    SciTech Connect

    Xi Yanbin; Liu Yue [MOE Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    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.

  9. 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.

  10. 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.

  11. 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

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Effects of high-frequency electromagnetic fields emitted from card readers of access control systems on electronic pocket dosimeters

    Microsoft Academic Search

    Shizuhiko Deji; Kunihide Nishizawa

    2005-01-01

    High-frequency electromagnetic fields in the 120kHz band emitted from card readers for access control systems caused abnormally high doses on electronic pocket dosimeters (EPDs). All EPDs recovered their normal performance by resetting after the exposure ceased. The electric and magnetic immunity levels of the EPDs were estimated by using the distances needed to prevent electromagnetic interference.

  14. Design optimization of automotive electronic control unit using the analysis of common-mode current by fast electromagnetic field solver

    Microsoft Academic Search

    Yuji Okazaki; Masaki Unno; Takanori Uno; Hideki Asai

    2010-01-01

    In this paper, we propose an optimization system based on the fast electromagnetic field solver and metaheuristics for reducing electromagnetic interference (EMI) on electronic control unit (ECU). We adopt simulated annealing (SA), genetic algorithm (GA) and taboo search (TS) to seek optimal solutions, and the finite difference time domain (FDTD) method with general purpose computing on graphic processing unit (GPGPU)

  15. Response of the CALICE Si-W electromagnetic calorimeter physics prototype to electrons

    NASA Astrophysics Data System (ADS)

    Adloff, C.; Karyotakis, Y.; Repond, J.; Yu, J.; Eigen, G.; Hawkes, C. M.; Mikami, Y.; Miller, O.; Watson, N. K.; Wilson, J. A.; Goto, T.; Mavromanolakis, G.; Thomson, M. A.; Ward, D. R.; Yan, W.; Benchekroun, D.; Hoummada, A.; Krim, M.; Benyamna, M.; Boumediene, D.; Brun, N.; Crloganu, C.; Gay, P.; Morisseau, F.; Blazey, G. C.; Chakraborty, D.; Dyshkant, A.; Francis, K.; Hedin, D.; Lima, G.; Zutshi, V.; Hostachy, J.-Y.; Morin, L.; D'Ascenzo, N.; Cornett, U.; David, D.; Fabbri, R.; Falley, G.; Gadow, K.; Garutti, E.; Gttlicher, P.; Jung, T.; Karstensen, S.; Korbel, V.; Lucaci-Timoce, A.-I.; Lutz, B.; Meyer, N.; Morgunov, V.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Vargas-Trevino, A.; Wattimena, N.; Wendt, O.; Feege, N.; Groll, M.; Haller, J.; Heuer, R.-D.; Richter, S.; Samson, J.; Kaplan, A.; Schultz-Coulon, H.-Ch.; Shen, W.; Tadday, A.; Bilki, B.; Norbeck, E.; Onel, Y.; Kim, E. J.; Baek, N. I.; Kim, D.-W.; Lee, K.; Lee, S. C.; Kawagoe, K.; Tamura, Y.; Bowerman, D. A.; Dauncey, P. D.; Magnan, A.-M.; Yilmaz, H.; Zorba, O.; Bartsch, V.; Postranecky, M.; Warren, M.; Wing, M.; Faucci Giannelli, M.; Green, M. G.; Salvatore, F.; Bedjidian, M.; Kieffer, R.; Laktineh, I.; Bailey, D. S.; Barlow, R. J.; Kelly, M.; Thompson, R. J.; Danilov, M.; Tarkovsky, E.; Baranova, N.; Karmanov, D.; Korolev, M.; Merkin, M.; Voronin, A.; Frey, A.; Lu, S.; Prothmann, K.; Simon, F.; Bouquet, B.; Callier, S.; Cornebise, P.; Fleury, J.; Li, H.; Richard, F.; de la Taille, Ch.; Poeschl, R.; Raux, L.; Ruan, M.; Seguin-Moreau, N.; Wicek, F.; Anduze, M.; Boudry, V.; Brient, J.-C.; Gaycken, G.; Mora e Freitas, P.; Musat, G.; Reinhard, M.; Roug, A.; Vanel, J.-Ch.; Videau, H.; Park, K.-H.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Ruzicka, P.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Belhorma, B.; Belmir, M.; Nam, S. W.; Park, I. H.; Yang, J.; Chai, J.-S.; Kim, J.-T.; Kim, G.-B.; Kang, J.; Kwon, Y.-J.

    2009-09-01

    A prototype silicon-tungsten electromagnetic calorimeter (ECAL) for an international linear collider (ILC) detector was installed and tested during summer and autumn 2006 at CERN. The detector had 6480 silicon pads of dimension 11 cm2. Data were collected with electron beams in the energy range 6-45 GeV. The analysis described in this paper focuses on electromagnetic shower reconstruction and characterises the ECAL response to electrons in terms of energy resolution and linearity. The detector is linear to within approximately the 1% level and has a relative energy resolution of (16.530.14(stat)0.4(syst))/?{E(GeV)}?(1.070.07(stat)0.1(syst)) (%). The spatial uniformity and the time stability of the ECAL are also addressed.

  16. 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).

  17. Plasma instability and amplification of electromagnetic waves in low-dimensional electron systems

    Microsoft Academic Search

    S. A. Mikhailov

    1998-01-01

    A general electrodynamic theory of a grating coupled two dimensional electron\\u000asystem (2DES) is developed. The 2DES is treated quantum mechanically, the\\u000agrating is considered as a periodic system of thin metal strips or as an array\\u000aof quantum wires, and the interaction of collective (plasma) excitations in the\\u000asystem with electromagnetic field is treated within the classical\\u000aelectrodynamics. It

  18. A long electromagnetic wiggler for the PALADIN free-electron laser experiments

    Microsoft Academic Search

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

    1988-01-01

    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.

  19. Electronic properties of carbon nanotubes investigated by means of standard electromagnetic simulators

    Microsoft Academic Search

    Davide Mencarelli; Tullio Rozzi; Luca Maccari; Andrea di Donato; Marco Farina

    2007-01-01

    Due to the formal analogy between Maxwell and Schrdinger equations, electromagnetic (e.m.) simulators may become a powerful numerical tool for the analysis of carrier transport in low-dimensional systems. In the following, we exploit this analogy in order to investigate the electronic properties of carbon nanotubes (CNTs). As a matter of fact, e.m. commercial solvers have reached a high degree of

  20. Electromagnetic electron temperature anisotropy instability in the earth's magnetotail plasma sheet

    NASA Astrophysics Data System (ADS)

    Nikutowski, B.

    1989-01-01

    The electromagnetic fire hose instability driven by an electron temperature anisotropy is considered for parallel propagating waves as a possible explanation for the observations of magnetic noise bursts in the central plasma sheet of the geomagnetic tail. The approximative condition for instability is given. The fire hose instability could generate a wave frequency spectrum up to 3Hz with a maximum growth rate at 1Hz in the central plasma sheet.

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

    Microsoft Academic Search

    M. Temerin; R. L. Lysak

    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

  2. Development of a Compact Electron Beam Ion Source Cooled with Liquid Nitrogen

    Microsoft Academic Search

    Kazuhiko Okuno

    1989-01-01

    A small-sized EBIS type ion source (mini-EBIS) for production of highly charged ions has been developed. The whole system, namely, the electron gun, ion drift tube, electron collector, ion extraction lens and liquid nitrogen reservoir containing solenoid coil is housed in a vacuum envelope, 150 mmphi in diameter and 500 mm in length. The idea of cooling the solenoid to

  3. Free-electron laser harmonic generation in an electromagnetic-wave wiggler and ion channel guiding

    SciTech Connect

    Mehdian, H.; Hasanbeigi, A.; Jafari, S. [Department of Physics and Institute for Plasma Research, Tarbiat Moallem University, 49 Dr Mofatteh Avenue, Tehran 15614 (Iran, Islamic Republic of)

    2010-02-15

    A theoretical study of electron trajectories, harmonic generation, and gain in a free-electron laser (FEL) with a linearly polarized electromagnetic-wave wiggler is presented for axial injection of electron beam. The relativistic equation of motion for a single electron has been derived and solved numerically. It is found that the trajectories consist of two regimes. The stability of these regimes has been investigated. The results show that the trajectories are stable except for some parts of the regime one. The effects of interaction on the transverse velocity of the electron are a superposition of two oscillation terms, one at the wiggler frequency and the other at the betatron ion-channel frequency. A detailed analysis of the gain equation in the low-gain-per-pass limit has been employed to investigate FEL operation in higher harmonics generation. The possibility of wave amplification at both wiggler frequency and betatron ion-channel frequency for their odd harmonics has been illustrated.

  4. 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.

  5. 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 JLabs 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.

  6. EXPERIMENTAL AND NUMERICAL STUDY OF TRANSIENT ELECTRONIC CHIP COOLING BY

    E-print Network

    needed for heat removal is particularly important in a wide range of electronic systems and vice versa. 1. INTRODUCTION The semiconductor industry has seen a rapid pace of growth in its products management for electronic chips [6]. Two-phase flow pat- terns and the influence of boiling flow on heat

  7. Longitudinal and transverse cooling of relativistic electron beams in intense laser pulses

    E-print Network

    Yoffe, Samuel R; Noble, Adam; Jaroszynski, Dino A

    2015-01-01

    With the emergence in the next few years of a new breed of high power laser facilities, it is becoming increasingly important to understand how interacting with intense laser pulses affects the bulk properties of a relativistic electron beam. A detailed analysis of the radiative cooling of electrons indicates that, classically, equal contributions to the phase space contraction occur in the transverse and longitudinal directions. In the weakly quantum regime, in addition to an overall reduction in beam cooling, this symmetry is broken, leading to significantly less cooling in the longitudinal than the transverse directions. By introducing an efficient new technique for studying the evolution of a particle distribution, we demonstrate the quantum reduction in beam cooling, and find that it depends on the distribution of energy in the laser pulse, rather than just the total energy as in the classical case.

  8. An off-axis 50-period electromagnet wiggler for millimeter-wave free-electron laser experiment

    Microsoft Academic Search

    K. K. Mohandas; A. V. Ravi Kumar; K. K. Jain

    2000-01-01

    An off-axis 50-period planar, short-wavelength (~10 mm) electromagnet wiggler is developed and characterized for millimeter-wave generation using a sheet electron beam in a free-electron laser experiment. Three-dimensional (3-D) magnetic field measurements of the electromagnet wiggler have been carried out. The measured wiggler magnetic field is 0.16 G\\/A 3% while the mean value of wiggler wavelength is 0.9983% cm. Due to

  9. Designing electron refrigerators for improved cooling with an expanded thermal model

    Microsoft Academic Search

    Galen O'Neil; Erik Larson; Joel Ullom

    2009-01-01

    Normal-metal\\/insulator\\/superconductor (NIS) tunnel junctions can act as refrigerators below 1K. Biasing the junction such that only thermally excited electrons have energy higher than the superconducting gap causes selective tunneling which cools the normal metal electrode. Because of their small size, low mass, and absence of moving parts, NIS refrigerators are an attractive cooling technology for space and industrial applications. We

  10. Performance of wire-on-tube heat exchangers used in immersion cooling for electronic packages

    Microsoft Academic Search

    G. A. Quadir; C. B. Leong; G. M. Krishnan; K. N. Seetharamu

    2000-01-01

    In this investigation, closed loop immersion cooling of an electronic package with external condenser-a wire-on-tube heat exchanger being attached to its enclosure-is analysed. The dielectric vapour leaving the enclosure flows through the tubes of the heat exchanger. The vapour is then cooled by ambient air in free or forced convection environments. The finite element method is used in the analysis.

  11. Gain-enhanced free-electron laser with an electromagnetic pump field

    NASA Technical Reports Server (NTRS)

    Hiddleston, H. R.; Segall, S. B.; Catella, G. C.

    1982-01-01

    The feasibility of enhancing the gain for the free electron laser (FEL) with an electromagnetic (EM) pump field has been considered. The enhancement is provided by reacceleration of the electrons in the interaction region by means of a static, axial electric field. A FEL utilizing a low energy electron beam and a wiggler magnet with a periodicity on the order of 1 cm would produce far infared (FIR) radiation with wavelengths on the order of a few hundred microns. The use of the FIR radiation as the pump field in a two-stage FEL is envisioned to obtain visible radiation with a low energy electron beam. A summary is provided regarding the theory and equations of motion for the EM-pumped FEL. The derived relations are applied to the second stage of such a two-stage FEL. The obtained equations have been incorporated into a computer code which has been used to calculate laser gain and energy conversion efficiency.

  12. 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.

  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. 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

  15. Rotational cooling of HD+ molecular ions by superelastic collisions with electrons.

    PubMed

    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 DeltaJ=-2 SEC rate coefficients, which are predicted to be dominant as opposed to the DeltaJ=-1 rates and to amount to (1-2)x10;{-6} cm;{3} s;{-1} for initial angular momentum states with J< or =7, to within 30%. PMID:19658863

  16. Perpendicular propagating electromagnetic envelope solitons in electron-positron-ion plasma

    SciTech Connect

    Jehan, Nusrat [Department of Physics, Theoretical Plasma Physics Group, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Pakistan Atomic Energy Commission, P.O. Box 1114, Islamabad 44000 (Pakistan); Salahuddin, M. [Pakistan Atomic Energy Commission, P.O. Box 1114, Islamabad 44000 (Pakistan); Mirza, Arshad M. [Department of Physics, Theoretical Plasma Physics Group, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

    2010-05-15

    The nonlinear amplitude modulation of electromagnetic waves propagating perpendicular to the direction of ambient magnetic field in a uniform collisionless magnetized electron-positron-ion plasma is studied. The Krylov-Bogoliubov-Mitropolsky perturbation method is employed to derive nonlinear Schroedinger equation, which describes the amplitude dynamics of perturbed magnetic field. The modulation instability criterion reveals that the low frequency mode is always stable, whereas the high frequency mode becomes modulationally unstable for certain ranges of wave number and positron-to-electron density ratio. Furthermore, the positron-to-electron density ratio as well as the strength of ambient magnetic field is found to have significant effect on the solitary wave solutions of the nonlinear Schroedinger equation, namely, dark and bright envelope solitons.

  17. Some energy and angular characteristics of electrons in electromagnetic cascades in air

    NASA Astrophysics Data System (ADS)

    Stanev, T.; Vankov, Kh.; Petrov, S.; Elbert, J. W.

    The angular distribution of electrons with threshold energies of 20 MeV (the lowest energy at which electrons radiate Cerenkov photons in the air) are considered. The results are based on Monte Carlo calculations of the development of electromagnetic cascades. A set of showers with energy thresholds equals 20 MeV and primary photon energies equals 10, 20, 30, and 100 GeV is simulated. Information about the particle properties (energy, angle, and radial displacement) is provided at each radiation length of depth. The electrons are at much smaller angles to the shower axis than were those of Messel and Crawford (1970); this explains the discrepancy in angular distribution of Cerenkov light in air between the two.

  18. Near-Infrared Spectroscopy at McDonald Observatory: B.1 The CoolSpec Electronics Control System

    E-print Network

    Colorado at Boulder, University of

    Spec Electronics Control System CoolSpec is near-infrared, grating spectrometer available for use on the 2.7-m Harlan J. Smith telescope at McDonald Observatory. CoolSpec is com- posed of a cooled dewar which houses the spectrometer optics; the dewar is coupled to an independent near-infrared camera, ROKCAM (see Appendix A

  19. 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 Alfvn 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, ?(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

  20. 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.

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

    SciTech Connect

    Vagin, K. Yu., E-mail: vagin@sci.lebedev.ru; Uryupin, S. A., E-mail: uryupin@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    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.

  2. Damping of electromagnetic waves due to electron-positron pair production

    E-print Network

    S. S. Bulanov; A. M. Fedotov; F. Pegoraro

    2004-09-27

    The problem of the backreaction during the process of electron-positron pair production by a circularly polarized electromagnetic wave propagating in a plasma is investigated. A model based on the relativistic Boltzmann-Vlasov equation with a source term corresponding to the Schwinger formula for the pair creation rate is used. The damping of the wave, the nonlinear up-shift of its frequency due to the plasma density increase and the effect of the damping on the wave polarization and on the background plasma acceleration are investigated as a function of the wave amplitude.

  3. Experimental study of diffusive cooling of electrons in a pulsed inductively coupled plasma.

    PubMed

    Maresca, Antonio; Orlov, Konstantin; Kortshagen, Uwe

    2002-05-01

    Langmuir probe measurements of the temporal behavior of the electron distribution function in a low-pressure inductive discharge are presented. The structure of the measured distribution functions suggests that the loss of high energetic electrons to the wall of the discharge chamber is the main energy loss mechanism. Electron-heavy-particle collisions play only a secondary role for the energy loss. The rapid loss of energetic electrons--while low energy electrons remain confined in the space charge potential field--leads to a fast cooling of the electron distribution function. We also present a simple model to describe the evolution of the mean kinetic energy and plasma potential on the basis of a distribution function that is cutoff at energies above the potential electron energy at the wall. PMID:12059713

  4. Experimental study of diffusive cooling of electrons in a pulsed inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Maresca, Antonio; Orlov, Konstantin; Kortshagen, Uwe

    2002-05-01

    Langmuir probe measurements of the temporal behavior of the electron distribution function in a low-pressure inductive discharge are presented. The structure of the measured distribution functions suggests that the loss of high energetic electrons to the wall of the discharge chamber is the main energy loss mechanism. Electron-heavy-particle collisions play only a secondary role for the energy loss. The rapid loss of energetic electrons-while low energy electrons remain confined in the space charge potential field-leads to a fast cooling of the electron distribution function. We also present a simple model to describe the evolution of the mean kinetic energy and plasma potential on the basis of a distribution function that is cutoff at energies above the potential electron energy at the wall.

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

    SciTech Connect

    Rahmani, Z., E-mail: z.rahmani@kashanu.ac.ir; Jazi, B. [Department of Laser and Photonics, Faculty of Physics, University of Kashan, Kashan (Iran, Islamic Republic of); Heidari-Semiromi, E. [Department of Condense Matter, Faculty of Physics, University of Kashan, Kashan (Iran, Islamic Republic of)

    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.

  6. Energy Linearity and Resolution of the ATLAS Electromagnetic Barrel Calorimeter in an Electron Test-Beam

    E-print Network

    Aharrouche, M; Di Ciaccio, L; El-Kacimi, M; Gaumer, O; Gouanre, M; Goujdami, D; Lafaye, R; Laplace, S; Le Maner, C; Neukermans, L; Perrodo, P; Poggioli, L; Prieur, D; Przysiezniak, H; Sauvage, G; Tarrade, F; Wingerter-Seez, I; Zitoun, R; Lanni, F; Ma, H; Rajagopalan, S; Rescia, S; Takai, H; Belymam, A; Benchekroun, D; Hakimi, M; Hoummada, A; Barberio, E; Gao, Y S; L, L; Stroynowski, R; Aleksa, Martin; Beck-Hansen, J; Carli, T; Efthymiopoulos, I; Fassnacht, P; Follin, F; Gianotti, F; Hervs, L; Lampl, W; Collot, J; Hostachy, J Y; Ledroit-Guillon, F; Martin, P; Ohlsson-Malek, F; Saboumazrag, S; Leltchouk, M; Parsons, J A; Seman, M; Simion, S; Banfi, D; Carminati, L; Cavalli, D; Costa, G; Delmastro, M; Fanti, M; Mandelli, L; Mazzanti, M; Tartarelli, F; Bourdarios, C; Fayard, L; Fournier, D; Graziani, G; Hassani, S; Iconomidou-Fayard, L; Kado, M; Lechowski, M; Lelas, M; Parrour, G; Puzo, P; Rousseau, D; Sacco, R; Serin, L; Unal, G; Zerwas, D; Camard, A; Lacour, D; Laforge, B; Nikolic-Audit, I; Schwemling, P; Ghazlane, H; Cherkaoui-El-Moursli, R; Idrissi Fakhr-Eddine, A; Boonekamp, M; Kerschen, N; Mansouli, B; Meyer, P; Schwindling, J; Lund-Jensen, B; Tayalati, Y

    2006-01-01

    A module of the ATLAS electromagnetic barrel liquid argon calorimeter was exposed to the CERN electron test-beam at the H8 beam line upgraded for precision momentum measurement. The available energies of the electron beam ranged from 10 to 245 GeV. The electron beam impinged at one point corresponding to a pseudo-rapidity of eta=0.687 and an azimuthal angle of phi=0.28 in the ATLAS coordinate system. A detailed study of several effects biasing the electron energy measurement allowed an energy reconstruction procedure to be developed that ensures a good linearity and a good resolution. Use is made of detailed Monte Carlo simulations based on Geant which describe the longitudinal and transverse shower profiles as well as the energy distributions. For electron energies between 15 GeV and 180 GeV the deviation of the measured incident electron energy over the beam energy is within 0.1%. The systematic uncertainty of the measurement is about 0.1% at low energies and negligible at high energies. The energy resoluti...

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

    NASA Astrophysics Data System (ADS)

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

    2008-04-01

    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?(?/?)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 (10-10s) 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 ??2? characterizes a true versus constrained random process. The implications of the new relation describing the phenomena are discussed in the light of applications.

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

  9. 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 [Collider Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    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.

  10. Simultaneous observations of subauroral electron temperature enhancements and electromagnetic ion cyclotron waves

    NASA Technical Reports Server (NTRS)

    Erlandson, R. E.; Aggson, T. L.; Hogey, W. R.; Slavin, J. A.

    1993-01-01

    Observational results from an investigation of LF (0.5-4.0 Hz) electromagnetic ion cyclotron waves and subauroral electron temperature enhancements recorded from the DE-2 satellite are presented. Four different wave events were analyzed, all recorded at magnetic latitudes from 57-60 deg, magnetic local times from 8-14 hr, and altitudes from 600-900 km. The peak wave amplitudes during the events ranged from 8-70 nT and 5-30 mV/m in the magnetic and electric field, respectively. Te enhancements at the time of the waves were observed in three of four events. A linear relationship between the wave magnetic field spectral density and Te enhancements was found for these events. The Te enhancements were also correlated with an enhanced flux of low energy electrons. During one event (82104) an enhanced flux of electrons were observed at energies up to 50 eV and at nearly all pitch angles, although the flux was largest in the precipitating and upflowing directions. It is suggested that the waves are responsible for heating the low energy electrons which precipitate to the ionosphere and produce the observed Te enhancements. The upflowing electron population appears to be heated at ionospheric altitudes, below the DE-2 satellite.

  11. A perturbation theory study of electron vortices in electromagnetic fields: the case of infinitely long line charge and magnetic dipole.

    PubMed

    Xie, L; Wang, P; Pan, X Q

    2014-08-01

    The novel discovery of electron vortices carrying quantized orbital angular momentum motivated intensive research of their basic properties as well as applications, e.g. structural characterization of magnetic materials. In this paper, the fundamental interactions of electron vortices within infinitely long atomic-column-like electromagnetic fields are studied based on the relativistically corrected Pauli-Schrdinger equation and the perturbation theory. The relative strengths of three fundamental interactions, i.e. the electron-electric potential interaction, the electron-magnetic potential/field interaction and the spin-orbit coupling are discussed. The results suggest that the perturbation energies of the last two interactions are in an order of 10(3)-10(4) smaller than that of the first one for electron vortices. In addition, it is also found that the strengths of these interactions are strongly dependant on the spatial distributions of the electromagnetic field as well as the electron vortices. PMID:24690540

  12. Dispersion relation and growth rate in electromagnetically pumped free-electron lasers with ion-channel guiding

    SciTech Connect

    Mehdian, H.; Hasanbeigi, A.; Jafari, S. [Department of Physics and Institute for Plasma Research, Tarbiat Moallem University, 49 Dr Mofatteh Avenue, Tehran 15614 (Iran, Islamic Republic of)

    2008-07-15

    A theory of electromagnetic-wave wiggler with ion-channel guiding is presented. Steady-state electron trajectories are obtained by solving the equations of motion for a single electron in a free-electron laser with electromagnetic-wave wiggler and ion-channel guiding field. The eighth-degree polynomial dispersion equation for electromagnetic and space charge waves in this configuration is derived. The characteristics of dispersion relation are analyzed in detail by numerical solutions. It is found that the growth rate for group I and II orbits has been affected by the presence of the ion-channel guiding and the growth rate for group II orbits is more affected.

  13. 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.

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

    SciTech Connect

    Kazinski, P.O., E-mail: kpo@phys.tsu.ru

    2013-12-15

    The late time asymptotics of the physical solutions to the LorentzDirac equation in the electromagnetic external fields of simple configurationsthe constant homogeneous field, the linearly polarized plane wave (in particular, the constant uniform crossed field), and the circularly polarized plane waveare found. The solutions to the LandauLifshitz 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 LorentzDirac 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.

  15. Enhanced nonlinear interaction of powerful electromagnetic waves with ionospheric plasma near the second electron gyroharmonic

    SciTech Connect

    Istomin, Ya. N. [P. N. Lebedev Physical Institute, Leninsky Prospect 53, 119991 Moscow (Russian Federation)] [P. N. Lebedev Physical Institute, Leninsky Prospect 53, 119991 Moscow (Russian Federation); Leyser, T. B. [Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala (Sweden)] [Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala (Sweden)

    2013-05-15

    Plasma experiments in which a powerful electromagnetic pump wave is transmitted into the ionosphere from the ground give access to a rich range of phenomena, including gyroharmonic effects when the pump frequency is near an harmonic of the ionospheric electron gyrofrequency. For pump frequencies close to the second gyroharmonic, experiments show a strong enhancement, as observed in radar scatter from pump-induced geomagnetic field-aligned density striations and optical emissions. This is in contrast to the case at the third harmonic and higher at which most of the effects are instead suppressed. We show theoretically that electrostatic oscillations can be localized in density inhomogeneities associated with small scale striations. The localized field is a mixture of the electron Bernstein and upper hybrid modes when the pump frequency is near the second gyroharmonic. The coupling of the modes is enabled by a symmetry feature of the linear electron Bernstein and upper hybrid dispersion properties that occur only near the second gyroharmonic. Electron acceleration inside the density inhomogeneities by localized azimuthal electrostatic oscillations is more efficient near the second gyroharmonic than at higher frequencies, consistent with the observed enhancements.

  16. Enhanced nonlinear interaction of powerful electromagnetic waves with ionospheric plasma near the second electron gyroharmonic

    NASA Astrophysics Data System (ADS)

    Istomin, Ya. N.; Leyser, T. B.

    2013-05-01

    Plasma experiments in which a powerful electromagnetic pump wave is transmitted into the ionosphere from the ground give access to a rich range of phenomena, including gyroharmonic effects when the pump frequency is near an harmonic of the ionospheric electron gyrofrequency. For pump frequencies close to the second gyroharmonic, experiments show a strong enhancement, as observed in radar scatter from pump-induced geomagnetic field-aligned density striations and optical emissions. This is in contrast to the case at the third harmonic and higher at which most of the effects are instead suppressed. We show theoretically that electrostatic oscillations can be localized in density inhomogeneities associated with small scale striations. The localized field is a mixture of the electron Bernstein and upper hybrid modes when the pump frequency is near the second gyroharmonic. The coupling of the modes is enabled by a symmetry feature of the linear electron Bernstein and upper hybrid dispersion properties that occur only near the second gyroharmonic. Electron acceleration inside the density inhomogeneities by localized azimuthal electrostatic oscillations is more efficient near the second gyroharmonic than at higher frequencies, consistent with the observed enhancements.

  17. Low energy electron cooling induced by a magnetic field in high pressure capacitive radio frequency discharges

    SciTech Connect

    You, S.J.; Kim, S.S.; Chang, H.Y. [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)

    2004-11-22

    A study is conducted on a magnetic field effect on electron heating in capacitive rf discharges under a collisional regime, where the electron mean collision frequency is much higher than the rf frequency. The evolution of an electron energy distribution function (EEDF) over a magnetic field range of 0-30 G in 300 mTorr Ar discharges is measured and calculated for the investigation. A significant change in the low-energy range of the EEDF is found during the evolution. The observed result reveals the application of the magnetic field to the high-pressure capacitive plasma gives rise to a cooling effect on the low-energy electrons. This is in contrast to the low-pressure case where the magnetic field enhances the low-energy electron heating. The calculated result of the EEDF is in good agreement with the experiment.

  18. COOLING RATES FOR RELATIVISTIC ELECTRONS UNDERGOING COMPTON SCATTERING IN STRONG MAGNETIC FIELDS

    SciTech Connect

    Baring, Matthew G.; Wadiasingh, Zorawar [Department of Physics and Astronomy, MS 108, Rice University, Houston, TX 77251 (United States); Gonthier, Peter L., E-mail: baring@rice.edu, E-mail: zw1@rice.edu, E-mail: gonthier@hope.edu [Department of Physics, Hope College, 27 Graves Place, Holland, MI 49423 (United States)

    2011-05-20

    For inner magnetospheric models of hard X-ray and gamma-ray emission in high-field pulsars and magnetars, resonant Compton upscattering is anticipated to be the most efficient process for generating continuum radiation. This is in part due to the proximity of a hot soft photon bath from the stellar surface to putative radiation dissipation regions in the inner magnetosphere. Moreover, because the scattering process becomes resonant at the cyclotron frequency, the effective cross section exceeds the classical Thomson value by over two orders of magnitude, thereby enhancing the efficiency of continuum production and the cooling of relativistic electrons. This paper presents computations of the electron cooling rates for this process, which are needed for resonant Compton models of non-thermal radiation from such highly magnetized pulsars. The computed rates extend previous calculations of magnetic Thomson cooling to the domain of relativistic quantum effects, sampled near and above the quantum critical magnetic field of 44.13 TG. This is the first exposition of fully relativistic, quantum magnetic Compton cooling rates for electrons, and it employs both the traditional Johnson and Lippmann cross section and a newer Sokolov and Ternov (ST) formulation of Compton scattering in strong magnetic fields. Such ST formalism is formally correct for treating spin-dependent effects that are important in the cyclotron resonance and has not been addressed before in the context of cooling by Compton scattering. The QED effects are observed to profoundly lower the rates below extrapolations of the familiar magnetic Thomson results, as expected, when recoil and Klein-Nishina reductions become important.

  19. High-coherence electron and ion bunches from laser-cooled atoms.

    PubMed

    Sparkes, Ben M; Thompson, Daniel J; McCulloch, Andrew J; Murphy, Dene; Speirs, Rory W; Torrance, Joshua S J; Scholten, Robert E

    2014-08-01

    Cold atom electron and ion sources produce electron bunches and ion beams by photoionization of laser-cooled atoms. They offer high coherence and the potential for high brightness, with applications including ultra-fast electron-diffractive imaging of dynamic processes at the nanoscale. The effective brightness of electron sources has been limited by nonlinear divergence caused by repulsive interactions between the electrons, known as the Coulomb explosion. It has been shown that electron bunches with ellipsoidal shape and uniform density distribution have linear internal Coulomb fields, such that the Coulomb explosion can be reversed using conventional optics. Our source can create bunches shaped in three dimensions and hence in principle achieve the transverse spatial coherence and brightness needed for picosecond-diffractive imaging with nanometer resolution. Here we present results showing how the shaping capability can be used to measure the spatial coherence properties of the cold electron source. We also investigate space-charge effects with ions and generate electron bunches with durations of a few hundred picoseconds. Future development of the cold atom electron and ion source will increase the bunch charge and charge density, demonstrate reversal of Coulomb explosion, and ultimately, ultra-fast coherent electron-diffractive imaging. PMID:24758916

  20. 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.

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

    SciTech Connect

    Zhukov, Alexander V., E-mail: alex-zhukov@sutd.edu.sg; Bouffanais, Roland [Singapore University of Technology and Design, 20 Dover Drive, Singapore 138682 (Singapore); Fedorov, E. G. [Volgograd State University of Architecture and Civil Engineering, 400074 Volgograd (Russian Federation); Belonenko, Mikhail B. [Laboratory of Nanotechnology, Volgograd Institute of Business, 400048 Volgograd (Russian Federation)

    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.

  2. 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. [Max-Planck-Institute fuer Kernphysik, Saupfercheckweg 1 D-69117 Heidelberg (Germany); Zajfman, D. [Max-Planck-Institute fuer Kernphysik, Saupfercheckweg 1 D-69117 Heidelberg (Germany); Department of Particle Physics, Weizmann Institute of Science, Rehovot, 76100 (Israel)

    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.

  3. Experimental study of diffusive and collisional cooling of electrons in a pulsed inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Hebert, Michael; Kortshagen, Uwe

    2002-10-01

    A cylindrical Langmuir probe has been used to obtain measurements of the temporal behavior of the electron distribution function in the afterglow of a low-pressure inductive discharge. For low pressures, the appearance of the measured electron distribution functions indicates that the loss of high energetic electrons to the wall of the discharge chamber is the main energy loss mechanism, where electron-heavy particle collisions play only a secondary role for the energy loss. While energetic electrons are rapidly lost to the walls, low energy electrons remain trapped within the ambipolar potential well, thus yielding a fast cooling of the electron distribution function. However, as the pressure is increased, the ion transport to the walls diminishes thus causing a reduction in the wall loss of electrons. This leads to a non-monotonous variation of the energy relaxation time this pressure. At low pressure when the electron wall loss is the main energy loss mechanism, the energy relaxation time increases with increasing pressure. At higher pressures, a transition to collisional energy relaxation is observed and the energy relaxation time decreases with increasing pressure.

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

    SciTech Connect

    Pandey, Shail; Bhattacharjee, Sudeep; Sahu, Debaprasad [Department of Physics, Indian Institute of Technology, Kanpur-208016 (India)

    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.

  5. 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.

  6. The application of two-phase push-pull cooling module in pin-fin array electronic device

    Microsoft Academic Search

    Chao Yu-Lin; Chao Fang-Lin

    1992-01-01

    A two-phase push-pull cooling module has been developed for cooling a pin-fin array electronic device. The measured results indicate that when the pin-fin array density is increased the performance of the push-pull module is better than that of traditional forced convection. It was also found that in forced convection cooling the temperature in the downstream region is much higher than

  7. Linear theory of the interaction of a helical electron beam with electromagnetic waves in a waveguide near the cutoff frequency

    Microsoft Academic Search

    A. E. Konevets; A. P. Chetverikov

    1989-01-01

    The conditions of the self-excitation and amplification of electromagnetic waves in a weakly relativistic electron beam\\/TE wave system in a waveguide near the cutoff frequency are investigated. The effect of distributed losses on the beam-wave interaction efficiency is examined. A method for enhancing the stability of the system with respect to parasitic self-excitation is discussed.

  8. New aspects of whistler waves driven by an electron beam studied by a 3-D electromagnetic code

    NASA Technical Reports Server (NTRS)

    Nishikawa, Ken-Ichi; Buneman, Oscar; Neubert, Torsten

    1994-01-01

    We have restudied electron beam driven whistler waves with a 3-D electromagnetic particle code. The simulation results show electromagnetic whistler wave emissions and electrostatic beam modes like those observed in the Spacelab 2 electron beam experiment. It has been suggested in the past that the spatial bunching of beam electrons associated with the beam mode may directly generate whistler waves. However, the simulation results indicate several inconsistencies with this picture: (1) whistler waves continue to be generated even after the beam mode space charge modulation looses its coherence, (2) the parallel (to the background magnetic field) wavelength of the whistler wave is longer than that of the beam instability, and (3) the parallel phase velocity of the whistler wave is smaller than that of the beam mode. The complex structure of the whistler waves in the vicinity of the beam suggest that the transverse motion (gyration) of the beam and background electrons is also involved in the generation of whistler waves.

  9. Electromagnetic Abdulaziz Hanif

    E-print Network

    Masoudi, Husain M.

    Electromagnetic Propulsion Abdulaziz Hanif Electrical Engineering Department King Fahd University of spacecraft, which would be jolted through space by electromagnets, could take us farther than any of these other methods. When cooled to extremely low temperatures, electromagnets demonstrate an unusual behavior

  10. 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.

  11. Electronics and Sensor Cooling with a Stirling Cycle for Venus Surface Mission

    NASA Technical Reports Server (NTRS)

    Mellott, Ken

    2004-01-01

    The inhospitable ambient surface conditions of Venus, with a 450 C temperature and 92 bar pressure, may likely require any extended-duration surface exploratory mission to incorporate some type of cooling for probe electronics and sensor devices. A multiple-region Venus mission study was completed at NASA GRC in December of 2003 that resulted in the preliminary design of a kinematically-driven, helium charged, Stirling cooling cycle with an estimated over-all COP of 0.376 to lift 100 watts of heat from a 200 C cold sink temperature and reject it at a hot sink temperature of 500 C. This paper briefly describes the design process and also describes and summarizes key features of the kinematic, Stirling cooler preliminary design concept.

  12. 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.

  13. The Influence of Longitudinal Space Charge Fields on the Modulation Process of Coherent Electron Cooling

    E-print Network

    Wang, Gang; Litvinenko, V N

    2014-01-01

    The initial modulation in the scheme for Coherent electron Cooling (CeC) rests on the screening of the ion charge by electrons. However, in a CeC system with a bunched electron beam, inevitably, a long-range longitudinal space charge force is introduced. For a relatively dense electron beam, its force can be comparable to, or even greater than the attractive force from the ions. Hence, the influence of the space charge field on the modulation process could be important. If the 3-D Debye lengths are much smaller than the extension of the electron bunch, the modulation induced by the ion happens locally. Then, in that case, we can approximate the long-range longitudinal space charge field as a uniform electric field across the region. As detailed in this paper, we developed an analytical model to study the dynamics of ion shielding in the presence of a uniform electric field. We solved the coupled Vlasov-Poisson equation system for an infinite anisotropic electron plasma, and estimated the influences of the lon...

  14. Possible modification of the cooling index of interstellar helium pickup ions by electron impact ionization in the inner heliosphere

    NASA Astrophysics Data System (ADS)

    Chen, Jun Hong; Bochsler, Peter; Mbius, Eberhard; Gloeckler, George

    2014-09-01

    Interstellar neutrals penetrating into the inner heliosphere are ionized by photoionization, charge exchange with solar wind ions, and electron impact ionization. These processes comprise the first step in the evolution of interstellar pickup ion (PUI) distributions. Typically, PUI distributions have been described in terms of velocity distribution functions that cool adiabatically under solar wind expansion, with a cooling index of 3/2. Recently, the cooling index has been determined experimentally in observations of He PUI distributions with Advanced Composition Explorer (ACE)/Solar Wind Ion Composition Spectrometer and found to vary substantially over the solar cycle. The experimental determination of the cooling index depends on the knowledge of the ionization rates and their spatial variation. Usually, ionization rates increase with 1/r2 as neutral particles approach the Sun, which is not exactly true for electron impact ionization, because the electron temperature increases with decreasing distance from the Sun due to the complexity of its distributions and different radial gradients in temperature. This different dependence on distance may become important in the study of the evolution of PUI distributions and is suspected as one of the potential reasons for the observed variation of the cooling index. Therefore, we investigate in this paper the impact of electron ionization on the variability of the cooling index. We find that the deviation of the electron ionization rate from the canonical 1/r2 behavior of other ionization processes plays only a minor role.

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

    SciTech Connect

    Rufai, O. R., E-mail: rajirufai@gmail.com; Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Belville (South Africa); Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai (India)

    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.

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

    SciTech Connect

    Heidari, E., E-mail: ehphys75@iaubushehr.ac.ir [Department of Sciences, Bushehr Branch, Islamic Azad University, Bushehr (Iran, Islamic Republic of); Aslaninejad, M. [Plasma Physics Research Centre, Science and Research Branch, Islamic Azad University, P.O. Box 14665-678, Tehran (Iran, Islamic Republic of)] [Plasma Physics Research Centre, Science and Research Branch, Islamic Azad University, P.O. Box 14665-678, Tehran (Iran, Islamic Republic of); Eshraghi, H. [Physics Department, Iran University of Science and Technology (IUST), P.O. Box 1684613114, Tehran (Iran, Islamic Republic of)] [Physics Department, Iran University of Science and Technology (IUST), P.O. Box 1684613114, Tehran (Iran, Islamic Republic of); Rajaee, L. [Department of Physics, Faculty of Science, University of Qom, Qom (Iran, Islamic Republic of)] [Department of Physics, Faculty of Science, University of Qom, Qom (Iran, Islamic Republic of)

    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.

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

    NASA Astrophysics Data System (ADS)

    Schn, 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 mm14 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.

  19. 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.

  20. 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.

  1. Nonlinear propagation of electromagnetic ion-cyclotron waves in an electron-ion plasma in the presence of ion temperature gradient drift

    Microsoft Academic Search

    G. Murtaza; M. Nadeem; P. K. Shukla

    1993-01-01

    Nonlinear coupling between the electromagnetic ion cyclotron waves and the background ion-temperature gradient drift modes is investigated in an electron-ion plasma. This interaction is governed by a system of two coupled equations consisting of a nonlinear Schrdinger equation for the electromagnetic wave envelopes and a dynamical equation, derived from the Braginskii's fluid model, for the drift fluctuations. A general dispersion

  2. Influence of lateral target size on hot electron production and electromagnetic pulse emission from laser-irradiated metallic targets

    SciTech Connect

    Chen Ziyu; Li Jianfeng; Yu Yong; Li Xiaoya; Peng Qixian; Zhu Wenjun [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Wang Jiaxiang [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China)

    2012-11-15

    The influences of lateral target size on hot electron production and electromagnetic pulse emission from laser interaction with metallic targets have been investigated. Particle-in-cell simulations at high laser intensities show that the yield of hot electrons tends to increase with lateral target size, because the larger surface area reduces the electrostatic field on the target, owing to its expansion along the target surface. At lower laser intensities and longer time scales, experimental data characterizing electromagnetic pulse emission as a function of lateral target size also show target-size effects. Charge separation and a larger target tending to have a lower target potential have both been observed. The increase in radiation strength and downshift in radiation frequency with increasing lateral target size can be interpreted using a simple model of the electrical capacity of the target.

  3. 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.

  4. 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).

  5. Electromagnetic wave analogue of an electronic diode This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-print Network

    Zheludev, Nikolay

    Electromagnetic wave analogue of an electronic diode This article has been downloaded from analogue of an electronic diode Ilya V Shadrivov1,3 , Vassili A Fedotov2 , David A Powell1 , Yuri S Kivshar://www.njp.org/ doi:10.1088/1367-2630/13/3/033025 Abstract. An electronic diode is a nonlinear semiconductor circuit

  6. 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.

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

    PubMed

    Schatz, H; Gupta, S; Mller, 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, ?(-) 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

  8. 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.

  9. 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.

  10. 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.

  11. Design principles and applications of a cooled CCD camera for electron microscopy.

    PubMed

    Faruqi, A R

    1998-01-01

    Cooled CCD cameras offer a number of advantages in recording electron microscope images with CCDs rather than film which include: immediate availability of the image in a digital format suitable for further computer processing, high dynamic range, excellent linearity and a high detective quantum efficiency for recording electrons. In one important respect however, film has superior properties: the spatial resolution of CCD detectors tested so far (in terms of point spread function or modulation transfer function) are inferior to film and a great deal of our effort has been spent in designing detectors with improved spatial resolution. Various instrumental contributions to spatial resolution have been analysed and in this paper we discuss the contribution of the phosphor-fibre optics system in this measurement. We have evaluated the performance of a number of detector components and parameters, e.g. different phosphors (and a scintillator), optical coupling with lens or fibre optics with various demagnification factors, to improve the detector performance. The camera described in this paper, which is based on this analysis, uses a tapered fibre optics coupling between the phosphor and the CCD and is installed on a Philips CM12 electron microscope equipped to perform cryo-microscopy. The main use of the camera so far has been in recording electron diffraction patterns from two dimensional crystals of bacteriorhodopsin--from wild type and from different trapped states during the photocycle. As one example of the type of data obtained with the CCD camera a two dimensional Fourier projection map from the trapped O-state is also included. With faster computers, it will soon be possible to undertake this type of work on an on-line basis. Also, with improvements in detector size and resolution, CCD detectors, already ideal for diffraction, will be able to compete with film in the recording of high resolution images. PMID:9889815

  12. Gamma ray signatures of ultra high energy cosmic ray accelerators: electromagnetic cascade versus synchrotron radiation of secondary electrons

    E-print Network

    Stefano Gabici; Felix A. Aharonian

    2006-10-12

    We discuss the possibility of observing ultra high energy cosmic ray sources inhigh energy gamma rays. Protons propagating away from their accelerators produce secondary electrons during interactions with cosmic microwave background photons. These electrons start an electromagnetic cascade that results in a broad band gamma ray emission. We show that in a magnetized Universe ($B \\gtrsim 10^{-12}$ G) such emission is likely to be too extended to be detected above the diffusebackground. A more promising possibility comes from the detection of synchrotron photons from the extremely energetic secondary electrons. Although this emission is produced in a rather extended region of size $\\sim 10Mpc$, it is expected to be point-like and detectable at GeV energies if the intergalactic magnetic field is at the nanogauss level.

  13. Experiment to measure the electric dipole moment (edm) of the electron using laser-cooled Cs atoms

    Microsoft Academic Search

    Yong-Sup Ihn; Daniel Heinzen

    2010-01-01

    The electron edm de is known to be smaller in magnitude than 1.6x10-27e.cm [1]. We will describe progress on an ongoing experiment designed to be sensitive to an electron EDM de as small as 10-29e.cm. The experiment will search for the resulting edm of the Cs atom, proportional to de, using laser-cooled Cs atoms held in an optical dipole force

  14. Solutions of nonlinear equation of the curvilinear electromagnetic wave theory for point and non-point electron

    E-print Network

    Alexander G. Kyriakos

    2005-03-09

    In previous paper we have shown that there is a special kind of nonlinear electrodynamics - Curvilinear Wave Electrodynamics (CWED), whose equations are mathematically equivalent to the equations of quantum electrodynamics. The purpose of the present paper is to show that in framework of CWED the known solutions of the nonlinear electromagnetic equations can be considered as the approximate solutions of the nonlinear equation of CWED. Another purpose of this paper is to show, that these solutions allow the description of electron-like particle of CWED as point of non-point particles, depending on mathematical approach.

  15. 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 [Graduate School of Frontier Sciences, University of Tokyo, Chiba 277-8568 (Japan)

    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.

  16. Design and electronics commissioning of the physics prototype of a Si-W electromagnetic calorimeter for the International Linear Collider

    NASA Astrophysics Data System (ADS)

    CALICE Collaboration; Repond, J.; Yu, J.; Hawkes, C. M.; Mikami, Y.; Miller, O.; Watson, N. K.; Wilson, J. A.; Mavromanolakis, G.; Thomson, M. A.; Ward, D. R.; Yan, W.; Badaud, F.; Boumediene, D.; Crloganu, C.; Cornat, R.; Gay, P.; Gris, Ph; Manen, S.; Morisseau, F.; Royer, L.; Blazey, G. C.; Chakraborty, D.; Dyshkant, A.; Francis, K.; Hedin, D.; Lima, G.; Zutshi, V.; Hostachy, J.-Y.; Morin, L.; Garutti, E.; Korbel, V.; Sefkow, F.; Groll, M.; Kim, G.; Kim, D.-W.; Lee, K.; Lee, S.; Kawagoe, K.; Tamura, Y.; Bowerman, D. A.; Dauncey, P. D.; Magnan, A.-M.; Noronha, C.; Yilmaz, H.; Zorba, O.; Bartsch, V.; Butterworth, J. M.; Postranecky, M.; Warren, M.; Wing, M.; Faucci Giannelli, M.; Green, M. G.; Salvatore, F.; Wu, T.; Bailey, D.; Barlow, R. J.; Kelly, M.; Snow, S.; Thompson, R. J.; Danilov, M.; Kochetkov, V.; Baranova, N.; Ermolov, P.; Karmanov, D.; Korolev, M.; Merkin, M.; Voronin, A.; Bouquet, B.; Callier, S.; Dulucq, F.; Fleury, J.; Li, H.; Martin-Chassard, G.; Richard, F.; de la Taille, Ch; Poeschl, R.; Raux, L.; Ruan, M.; Seguin-Moreau, N.; Wicek, F.; Zhang, Z.; Anduze, M.; Boudry, V.; Brient, J.-C.; Clerc, C.; Gaycken, G.; Jauffret, C.; Karar, A.; Mora de Freitas, P.; Musat, G.; Reinhard, M.; Roug, A.; Sanchez, A. L.; Vanel, J.-Ch; Videau, H.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Ruzicka, P.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Arestov, Yu; Baird, A.; Halsall, R. N.; Nam, S. W.; Park, I. H.; Yang, J.

    2008-08-01

    The CALICE collaboration is studying the design of high performance electromagnetic and hadronic calorimeters for future International Linear Collider detectors. For the electromagnetic calorimeter, the current baseline choice is a high granularity sampling calorimeter with tungsten as absorber and silicon detectors as sensitive material. A ``physics prototype'' has been constructed, consisting of thirty sensitive layers. Each layer has an active area of 18 18 cm2 and a pad size of 1 1 cm2. The absorber thickness totals 24 radiation lengths. It has been exposed in 2006 and 2007 to electron and hadron beams at the DESY and CERN beam test facilities, using a wide range of beam energies and incidence angles. In this paper, the prototype and the data acquisition chain are described and a summary of the data taken in the 2006 beam tests is presented. The methods used to subtract the pedestals and calibrate the detector are detailed. The signal-over-noise ratio has been measured at 7.630.01. Some electronics features have been observed; these lead to coherent noise and crosstalk between pads, and also crosstalk between sensitive and passive areas. The performance achieved in terms of uniformity and stability is presented.

  17. 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.

  18. 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.

  19. Self-fields in a free-electron laser with electromagnetic-wave wiggler and ion-channel guiding

    SciTech Connect

    Mehdian, H.; Hasanbeigi, A.; Jafari, S. [Department of Physics and Institute for Plasma Research, Tarbiat Moallem University, 49 Dr Mofatteh Avenue, Tehran 15614 (Iran, Islamic Republic of)

    2008-12-15

    A theory of self-fields in a free-electron laser with electromagnetic-wave wiggler and ion-channel guiding is presented. The equations of motion for an electron have been analyzed. This equation together with its numerical solutions shows that the first part of group I and II trajectories is unstable. The effects of self-fields on the gain for groups I and II orbits have also been investigated by deriving the gain formula and numerical calculation. A gain decrement is found due to the effects of self-fields for group I orbits, and the gain enhancement for group II orbits. The gain decrement (enhancement) arises from diamagnetic (paramagnetic) generated by the self-fields. The gain decrement (enhancement) increases by increasing the beam density.

  20. New method of modeling electronic circuits coupled with 3D electromagnetic finite element models

    Microsoft Academic Search

    J. R. Brauer; B. E. MacNeal; L. A. Larkin; V. D. Overbye

    1991-01-01

    New zero-dimensional or scalar electromagnetic finite elements, that have the time integral of electric scalar potential as their nodal variable are presented. There are three zero-dimensional element types, representing resistors, capacitors, and inductors. These elements can be easily combined with two- or three-dimensional elements, with three components of magnetic vector potential and the time integral of electric scalar potential as

  1. New method of modeling electronic circuits coupled with 3D electromagnetic finite element models

    Microsoft Academic Search

    J. R. Brauer; B. E. MacNeal; L. A. Larkin; V. D. Overbye

    1991-01-01

    New zero-dimensional or scalar electromagnetic finite elements taht have the time integral of electric scalar potential as their nodal variable are presented. There are three zero-dimensional element types, representing resistors, capacitors, and inductors. These elements can be easily combined with two- or three-dimensional elements, with three components of magnetic vector potential and the time integral of electric scalar potential as

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

    E-print Network

    P. O. Kazinski

    2013-06-06

    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. 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 of 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.

  3. Electromagnetic Noise Superimposed on the Electric Power Supply to Electronic Medical Equipment

    Microsoft Academic Search

    Eisuke Hanada; Kyoko Takano; Kenji Kodama

    2003-01-01

    The use of mobile medical electronic equipment driven at low electric power outputs has progressed rapidly in recent years. Voltage change and noise superimposed on the power supply could create obstacles to the operation of medical electronic equipment. We observed the quality of the power supply of medical electronic equipment in a university hospital, and found approximately 5% distortion on

  4. Velocity separation in electron beam by static electromagnetic field of helical symmetry

    Microsoft Academic Search

    Yury K. Kalynov; Michael I. Petelin; Andrey V. Savilov

    1999-01-01

    In a homogeneous magnetic field superimposed one a helically symmetric electrostatic one, the electron drift trajectory depends on the particle energy and on the particle velocity component relative to the magnetic field. These effects can be used (1) to suppress gyrotron magnetron-injection gun instabilities caused by electron reflection from the magnetic mirror and (2) for separation of electron beam energy

  5. Electromagnetic vortex fields, spin, and spin-orbit interactions in electron vortices.

    PubMed

    Lloyd, S M; Babiker, M; Yuan, J; Kerr-Edwards, C

    2012-12-21

    Electron vortices are shown to possess electric and magnetic fields by virtue of their quantized orbital angular momentum and their charge and current density sources. The spatial distributions of these fields are determined for a Bessel electron vortex. It is shown how these fields lead naturally to interactions involving coupling to the spin magnetic moment and spin-orbit interactions which are absent for ordinary electron beams. The orders of magnitude of the effects are estimated here for a?ngstrm scale electron vortices generated within a typical electron microscope. PMID:23368471

  6. 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.

  7. Microgravity experiments on boiling and applications: research activity of advanced high heat flux cooling technology for electronic devices in Japan.

    PubMed

    Suzuki, Koichi; Kawamura, Hiroshi

    2004-11-01

    Research and development on advanced high heat flux cooling technology for electronic devices has been carried out as the Project of Fundamental Technology Development for Energy Conservation, promoted by the New Energy and Industrial Technology Development Organization of Japan (NEDO). Based on the microgravity experiments on boiling heat transfer, the following useful results have obtained for the cooling of electronic devices. In subcooled flow boiling in a small channel, heat flux increases considerably more than the ordinary critical heat flux with microbubble emission in transition boiling, and dry out of the heating surface is disturbed. Successful enhancement of heat transfer is achieved by a capillary effect from grooved surface dual subchannels on the liquid supply. The critical heat flux increases 30-40 percent more than for ordinary subchannels. A self-wetting mechanism has been proposed, following investigation of bubble behavior in pool boiling of binary mixtures under microgravity. Ideas and a new concept have been proposed for the design of future cooling system in power electronics. PMID:15644356

  8. Relativistic electron precipitation events driven by electromagnetic ion-cyclotron waves

    SciTech Connect

    Khazanov, G., E-mail: george.v.khazanov@nasa.gov; Sibeck, D. [NASA Goddard Space FlightCenter, Greenbelt, Maryland 20771 (United States); Tel'nikhin, A.; Kronberg, T. [Department of Physics and Technology, Altai State University, Barnaul (Russian Federation)

    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.

  9. Thermal effects on the propagation of large-amplitude electromagnetic waves in magnetized relativistic electron-positron plasma.

    PubMed

    Domnguez, Macarena; Muoz, Vctor; Valdivia, Juan Alejandro

    2012-05-01

    The propagation of circularly polarized electromagnetic waves along a constant background magnetic field in an electron-positron plasma is calculated by means of both a fluid and a kinetic theory treatment. In the fluid theory, relativistic effects are included in the particle motion, the wave field, and in the thermal motion by means of a function f, which depends only on the plasma temperature. In this work we analyze the consistency of the fluid results with those obtained from a kinetic treatment, based on the relativistic Vlasov equation. The corresponding kinetic dispersion relation is numerically studied for various temperatures, and results are compared with the fluid treatment. Analytic expressions for the Alfvn velocity are obtained for the fluid and kinetic models, and it is shown that, in the kinetic treatment, the Alfvn branch is suppressed for large temperatures. PMID:23004888

  10. 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. [Kansai Photon Science Institute, JAEA, Kizugawa, Kyoto 619-0215 (Japan); Bulanov, Stepan S. [University of California, Berkeley, California 94720 (United States)

    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.

  11. Temporary Acceleration of Electrons While Inside an Intense Electromagnetic Pulse Kirk T. McDonald

    E-print Network

    McDonald, Kirk

    ., San Jose, CA 95461 (Nov. 20, 1997) A free electron can temporarily gain a very significant amount an explanation for the origin of cosmic rays. However, it has generally been recog- nized that if a wave-mean-square electric field Erms, and four-vector potential Aµ; e and m are the charge and mass of the electron, and c

  12. 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.

  13. Electron random walk and collisional crossover in a gas in presence of electromagnetic waves and magnetostatic fields

    SciTech Connect

    Bhattacharjee, Sudeep; Paul, Samit [Department of Physics, Indian Institute of Technology, Kanpur 208016, Uttar Pradesh (India); Dey, Indranuj [Kyushu University, Kasuga Kouen 6-1, Kasuga City, 816-8580 (Japan)

    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.

  14. 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(? /?)2/[1+C(? /?)]2, indicating a modification to the conventional field free square law N =A(? /?)2, where ? is the characteristic diffusion length and ? 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 ?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)105 V/m, ?c=5.5-1.6 ns for an unmagnetized microwave driven discharge at 1 Torr argon.

  15. Silicon-Tungsten Sampling Electromagnetic Calorimeter for the Tev Electron-Positron Linear Collider

    NASA Astrophysics Data System (ADS)

    Brient, Jean-Claude

    2005-02-01

    A high granularity 3D calorimeter providing a detailed picture of the showers, adequate for efficient pattern recognition and needed energy resolution is mandatory for exploiting the discovery potential of the planned e+e- linear collider. For the electromagnetic calorimeter, the CALICE collaboration proposes a highly granular tungsten-silicon sampling calorimeter. The silicon device is made of PIN diode matrices with readout pads of 1 1 cm2. Such a calorimeter suits perfectly the energy flow measurements and enables a detailed event reconstruction. A prototype in construction is described and the first measurements with a source or cosmic rays are presented. The planning for the next years R&D is also given.

  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. Progress of a room temperature electron cyclotron resonance ion source using evaporative cooling technology at Institute of Modern Physics

    NASA Astrophysics Data System (ADS)

    Lu, W.; Xiong, B.; Zhang, X. Z.; Sun, L. T.; Feng, Y. C.; Ma, B. H.; Guo, S. Q.; Cao, R.; Ruan, L.; Zhao, H. W.

    2014-02-01

    A new room temperature ECR ion source, Lanzhou Electron Cyclotron Resonance ion source No. 4 (LECR4, previously named DRAGON), is under intense construction at Institute of Modern Physics. LECR4 is designed to operate with 18 GHz microwave frequency. The maximum axial magnetic fields are 2.3 T at injection and 1.3 T at extraction, and the radial field at the plasma chamber wall of 76 mm inner diameter is 1.0-1.2 T. One of the unique features for LECR4 is that its axial solenoids are winded with solid square copper wires which are immersed in a kind of special evaporative cooling medium for cooling purpose. Till now, a prototype of the cooling system has been successfully constructed and tested, which has demonstrated that the cooling efficiency of the designed system could meet the requirements of LECR4 under the routine operation conditions. All the main components of the ion source have been completed. Assembly and commissioning is ongoing. The latest developments and test results will be presented in this paper.

  18. Progress of a room temperature electron cyclotron resonance ion source using evaporative cooling technology at Institute of Modern Physics

    SciTech Connect

    Lu, W., E-mail: luwang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xiong, B.; Guo, S. Q.; Cao, R.; Ruan, L. [Institute of Electrical Engineering, CAS, Beijing 100190 (China)] [Institute of Electrical Engineering, CAS, Beijing 100190 (China); Zhang, X. Z.; Sun, L. T.; Feng, Y. C.; Ma, B. H.; Zhao, H. W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000 (China)] [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000 (China)

    2014-02-15

    A new room temperature ECR ion source, Lanzhou Electron Cyclotron Resonance ion source No. 4 (LECR4, previously named DRAGON), is under intense construction at Institute of Modern Physics. LECR4 is designed to operate with 18 GHz microwave frequency. The maximum axial magnetic fields are 2.3 T at injection and 1.3 T at extraction, and the radial field at the plasma chamber wall of 76 mm inner diameter is 1.01.2 T. One of the unique features for LECR4 is that its axial solenoids are winded with solid square copper wires which are immersed in a kind of special evaporative cooling medium for cooling purpose. Till now, a prototype of the cooling system has been successfully constructed and tested, which has demonstrated that the cooling efficiency of the designed system could meet the requirements of LECR4 under the routine operation conditions. All the main components of the ion source have been completed. Assembly and commissioning is ongoing. The latest developments and test results will be presented in this paper.

  19. Timescales for radiation belt electron acceleration and loss due to resonant wave-particle interactions: 2. Evaluation for VLF chorus, ELF hiss, and electromagnetic ion cyclotron waves

    Microsoft Academic Search

    Danny Summers; Binbin Ni; Nigel P. Meredith

    2007-01-01

    Outer zone radiation belt electrons can undergo gyroresonant interaction with various magnetospheric wave modes including whistler-mode chorus outside the plasmasphere and both whistler-mode hiss and electromagnetic ion cyclotron (EMIC) waves inside the plasmasphere. To evaluate timescales for electron momentum diffusion and pitch angle diffusion, we utilize bounce-averaged quasi-linear diffusion coefficients for field-aligned waves with a Gaussian frequency spectrum in a

  20. Dense electron-hole plasma cooling due to second nonequilibrium-phonon bottleneck in CdS crystallites

    NASA Astrophysics Data System (ADS)

    Jur?nas, S.; Kuril?ik, G.; ukauskas, A.

    1998-11-01

    Quantitative evidence on the existence of a second nonequilibrium-phonon bottleneck for dense electron-hole plasma cooling in a highly excited polar semiconductor is presented. The bottleneck is caused by recurrent fusion of nonequilibrium LO phonons from their decay products (daughter phonons). Carrier cooling was experimentally investigated in CdS, which offers a favorable phonon dispersion. Crystallites of 50-nm radius were utilized to prevent stimulated recombination and diffusion of photoexcited electron-hole plasma with a density around 1.51019 cm-3. A transient of carrier effective temperature, deduced from time-resolved luminescence spectra, exhibit a slow-relaxation component with the time constant of 70 ps at room temperature. The transient was shown to be in quantitative consistence with the theoretical model based on Boltzmann equations for two generations of nonequilibrium phonons and degenerate-carrier energy rate equation with the energy income due to recombination effects (nonradiative capture via multiphonon emission, fermion self-heating, and band-gap renormalization) taken into account. The observed cooling rate agrees with two nonequilibrium-phonon bottlenecks with the depopulation time constants deduced from the available Raman data (0.5 ps for LO phonons and 12.4 ps for daughter phonons).

  1. 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.

  2. In situ electromagnetic field diagnostics with an electron plasma in a Penning-Malmberg trap

    E-print Network

    C. Amole; M. D. Ashkezari; M. Baquero-Ruiz; W. Bertsche; E. Butler; A. Capra; C. L. Cesar; M. Charlton; A. Deller; N. Evetts; S. Eriksson; J. Fajans; T. Friesen; M. C. Fujiwara; D. R. Gill; A. Gutierrez; J. S. Hangst; W. N. Hardy; M. E. Hayden; C. A. Isaac; S. Jonsell; L. Kurchaninov; A. Little; N. Madsen; J. T. K. McKenna; S. Menary; S. C. Napoli; K. Olchanski; A. Olin; P. Pusa; C. . Rasmussen; F. Robicheaux; E. Sarid; D. M. Silveira; C. So; S. Stracka; T. Tharp; R. I. Thompson; D. P. van der Werf; J. S. Wurtele

    2014-05-04

    We demonstrate a novel detection method for the cyclotron resonance frequency of an electron plasma in a Penning-Malmberg trap. With this technique, the electron plasma is used as an in situ diagnostic tool for measurement of the static magnetic field and the microwave electric field in the trap. The cyclotron motion of the electron plasma is excited by microwave radiation and the temperature change of the plasma is measured non-destructively by monitoring the plasma's quadrupole mode frequency. The spatially-resolved microwave electric field strength can be inferred from the plasma temperature change and the magnetic field is found through the cyclotron resonance frequency. These measurements were used extensively in the recently reported demonstration of resonant quantum interactions with antihydrogen.

  3. Temporary Acceleration of Electrons While Inside an Intense Electromagnetic Pulse Kirk T. McDonald

    E-print Network

    McDonald, Kirk

    ., San Jose, CA 95461 (Nov. 20, 1997) A free electron can temporarily gain a very significant amount an explanation for the origin of cosmic rays. However, it has generally been recognized that if a wave overtakes wavelength ?? 0 , root­mean­square electric field E rms , and four­vector potential A ¯ ; e and m

  4. Quantum Electrodynamics. III. The Electromagnetic Properties of the Electron-Radiative Corrections to Scattering

    Microsoft Academic Search

    Julian Schwinger

    1949-01-01

    The discussion of vacuum polarization in the previous paper of this series was confined to that produced by the field of a prescribed current distribution. We now consider the induction of current in the vacuum by an electron, which is a dynamical system and an entity indistinguishable from the particles associated with vacuum fluctuations. The additional current thus attributed to

  5. 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.

  6. Integrated three-dimensional module heat exchanger for power electronics cooling

    SciTech Connect

    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.

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

    Microsoft Academic Search

    Lowe

    2005-01-01

    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

  8. 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.

  9. Computation of Growth Rates and Threshold of the Electromagnetic Electron Temperature Gradient Modes in Tokamaks

    E-print Network

    Varun Tangri

    2013-01-29

    In this manuscript, eigenvalues of the Electron Temperature Gradient (ETG) modes and Ion Temperature Gradient (ITG) modes are determined numerically using Hermite and Sinc differentiation matrices based methods. It is shown that these methods are very useful for the computation of growth rates and threshold of the ETG and ITG modes. The total number of accurately computed eigenvalues for the modes have also been computed. The ideas developed here are also of relevance to other modes that use Ballooning formalism.

  10. 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.

  11. Tunability enhanced electromagnetic wiggler

    DOEpatents

    Schlueter, Ross D. (Albany, CA); Deis, Gary A. (Livermore, CA)

    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.

  12. 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.

  13. Electromagnetic formulation of global gyrokinetic particle simulation in toroidal geometry

    E-print Network

    Lin, Zhihong

    Electromagnetic formulation of global gyrokinetic particle simulation in toroidal geometry I. Holod online 9 December 2009 The fluid-kinetic hybrid electron model for global electromagnetic gyrokinetic the capabilities to describe low frequency processes in electromagnetic turbulence with electron dynamics

  14. 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.

  15. The theory of electro-magnetic radiation of electron transiting through the resonance-tunnel structure

    SciTech Connect

    Tkach, M.; Seti, Ju.; Voitsekhivska, O.; Fartushynsky, R. [Fedkovych Chernivtsi National University, 2 Kotsyubinskoho Str., 58012 Chernivtsi (Ukraine)

    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.

  16. An Intensity Modulator for Terahertz Electromagnetic Waves Utilizing Two-Dimensional Plasmon Resonance in a Dual-Grating-Gate High-Electron-Mobility Transistor

    NASA Astrophysics Data System (ADS)

    Nishimura, Takuya; Magome, Nobuhiro; Otsuji, Taiichi

    2010-05-01

    We propose an intensity modulator utilizing two-dimensional plasmons (2DPs) in a dual-grating-gate high-electron-mobility transistor. The device primarily functions as a plasmon-resonant emitter in which the seeds of non-radiative longitudinal modes of 2DPs are efficiently converted into radiative transverse modes of terahertz (THz) electromagnetic waves. In this work, we numerically study the behavior of the mode conversion between 2DPs and THz electromagnetic waves as a function of the 2DP dispersion. The finite difference time domain analysis demonstrates that the coupling of THz electromagnetic waves and 2DPs changes with the electron drift velocity and with the sheet electron density in 2DPs. The analysis also reveals that the intensity of transmitted waves can be modulated over a wide THz range with an extinction ratio beyond 60% by optimizing the sheet electron density and the drift velocity under nominal area-factor condition (ratio of the 2DP area over the total active channel area) up to 0.6.

  17. Optical Ramsey interferences on laser cooled and trapped atoms, detected by electron shelving

    Microsoft Academic Search

    K. Sengstock; U. Sterr; G. Hennig; D. Bettermann; J. H. Mller; W. Ertmer

    1993-01-01

    Based on a new detection scheme optical Ramsey fringes on the magnesium intercombination transition (lambda=457 nm) have been demonstrated with a resolution of 4 kHz and an accuracy of 1 Hz (Deltav\\/v ~210-15)using laser cooled and trapped atoms. Applying a pulsed excitation scheme to the trapped ensemble, the Ramsey signals are nearly undisturbed by the relativistic Doppler effect and phase

  18. Slalom Channeling of Trojan Electrons in 1-Dimensional Ion Chains in Linearly Polarized Electromagnetic Field

    NASA Astrophysics Data System (ADS)

    Kalinski, Matt

    2011-06-01

    We have recently discovered that two positively charged ions placed in the linearly polarized (LP) field aligned with to the symmetry line joining the ion charges and with the frequency twice the closed motion can support stable nondispersing Trojan wavepackets moving on perfectly 8-shaped trajectories [1]. Here we show that halfs of such trajectories can be connected to spline into long range oscillatory motion in the linear chain of positively charged ions. This results in long distance slalom channeling of electron travelling in Trojan state for a distance of large multiple of the ionic lattice constant. To keep the wavepacket nondispersing the LP field polarization must be perpendicular to the electron motion and strictly adjusted to the the period when the packet is passing and avoiding the neighboring ions. The channeling event is extremely rare in the phase space and requires the precise choice of the wave packet momentum and the initial position at the beginning of the long range oscillatory motion. For the majority of wrong initial conditions the motion results in fast trajectory binding on one of the chain ions. Numerical simulations with the split operator method are also provided. [1] M. Kalinski, ``Trojan-Like Wavepackets on 8-shaped orbits in Linearly Polarized Elctromagnetic Field in Hydrogen Ion Molecule,'' FiO 2009/LS XXV Annual Meeting, San Jose, California, October 2009.

  19. Electromagnetic envelope solitons in ultrarelativistic inhomogeneous electron-positron-ion plasma

    SciTech Connect

    Du, Hong-E; Cheng, Li-Hong; Yu, Zi-Fa; Xue, Ju-Kui, E-mail: xuejk@nwnu.edu.cn [Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronics Engineering, Northwest Normal University, Lanzhou 730070 (China)

    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.

  20. Electromagnetic field generation in the downstream of electrostatic shocks due to electron trapping.

    PubMed

    Stockem, A; Grismayer, T; Fonseca, R A; Silva, L O

    2014-09-01

    A new magnetic field generation mechanism in electrostatic shocks is found, which can produce fields with magnetic energy density as high as 0.01 of the kinetic energy density of the flows on time scales ?10(4)?pe-1. Electron trapping during the shock formation process creates a strong temperature anisotropy in the distribution function, giving rise to the pure Weibel instability. The generated magnetic field is well confined to the downstream region of the electrostatic shock. The shock formation process is not modified, and the features of the shock front responsible for ion acceleration, which are currently probed in laser-plasma laboratory experiments, are maintained. However, such a strong magnetic field determines the particle trajectories downstream and has the potential to modify the signatures of the collisionless shock. PMID:25238365

  1. Electromagnetic Field Generation in the Downstream of Electrostatic Shocks Due to Electron Trapping

    NASA Astrophysics Data System (ADS)

    Stockem, A.; Grismayer, T.; Fonseca, R. A.; Silva, L. O.

    2014-09-01

    A new magnetic field generation mechanism in electrostatic shocks is found, which can produce fields with magnetic energy density as high as 0.01 of the kinetic energy density of the flows on time scales 104?pe-1. Electron trapping during the shock formation process creates a strong temperature anisotropy in the distribution function, giving rise to the pure Weibel instability. The generated magnetic field is well confined to the downstream region of the electrostatic shock. The shock formation process is not modified, and the features of the shock front responsible for ion acceleration, which are currently probed in laser-plasma laboratory experiments, are maintained. However, such a strong magnetic field determines the particle trajectories downstream and has the potential to modify the signatures of the collisionless shock.

  2. Microslots : scalable electromagnetic instrumentation

    E-print Network

    Maguire, Yael G., 1975-

    2004-01-01

    This thesis explores spin manipulation, fabrication techniques and boundary conditions of electromagnetism to bridge the macroscopic and microscopic worlds of biology, chemistry and electronics. This work is centered around ...

  3. A parametric study of the influence of ion and electron properties on the excitation of electromagnetic ion cyclotron

    E-print Network

    Dasso, Sergio

    of electromagnetic ion cyclotron waves in coronal mass ejections Sergio Dasso1 Instituto de Fi´sica del Plasma, respectively) so that right-hand polarized electromagnetic ion cyclotron waves (EICWs) may be amplified instabilities, ion-cyclotron instability, thermal anisotropy Citation: Dasso, S., F. T. Gratton, and C. J

  4. Comment on ''Electron acceleration by a short laser beam in the presence of a long-wavelength electromagnetic wave'' [J. Appl. Phys. 102, 056106 (2007)

    SciTech Connect

    Yuan, C. J.; Wang, P. X. [Applied Ion Beam Physics Laboratory, Key Laboratory of the Ministry of Education, China and Department of Nuclear Science and Technology, Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Huang, S. J. [Department of Physics, Zhanjiang Normal University, Zhanjiang, Guangdong Province 524048 (China); Wang, J. X. [State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062 (China)

    2012-05-15

    Gupta et al.[J. Appl. Phys. 102, 056106 (2007)] investigated vacuum electron acceleration by a short laser beam in the presence of a long-wavelength electromagnetic wave. However, we consider that their simulation results to be questionable. We have investigated their simulation in detail and present our own simulation results, which do not match the good acceleration as theirs given in the original paper.

  5. 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. [Moscow State University, Faculty of Physics (Russian Federation)

    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.

  6. Cooled Transmission-Mode NEA-Photocathode with a Band-Graded Active Layer for High Brightness Electron Source

    NASA Astrophysics Data System (ADS)

    Jones, L. B.; Rozhkov, S. A.; Bakin, V. V.; Kosolobov, S. N.; Militsyn, B. L.; Scheibler, H. E.; Smith, S. L.; Terekhov, A. S.

    2009-08-01

    A Free-Electron Laser (FEL) places many exacting demands on a Negative Electron Affinity (NEA) photocathode, such as the need for an ultra-fast response time, low energy spread for emitted electrons, high quantum efficiency (Q.E.) and a high average photocurrent. However, these key requirements are conflicting, and cannot be fulfilled by conventional photocathode design. For example, to achieve 10 ps response time, the photocathode active layer should be thinned to 100-150 nm, but this thickness is insufficient to provide near-complete absorption of light with hv??g so high Q.E. cannot be achieved. Complete optical absorption and high Q.E. can be obtained using a thin active layer at higher photon energies, but this generates photoelectrons with excess kinetic energy within the semiconductor. These photoelectrons do not thermalise in a thin active layer, so yield a broad energy distribution in the emitted electrons. Moreover, cooling of the conventional semiconductor photocathode structure is ineffective due to its fragility, so it cannot be pressed firmly to a heat sink to attain good thermal contact. Consequently, the maximum CW photocurrent is limited to a few miiliamps. The goal of our work is to develop a new design of NEA-photocathode which is optimised for FEL applications.

  7. High frequency electromagnetic modes in a weakly magnetized relativistic electron plasma

    SciTech Connect

    Abbas, Gohar; Murtaza, G. [Department of Physics, G. C. University, Lahore 54000 (Pakistan); Kingham, R. J. [Plasma Physics Group, Imperial College, Blackett Laboratory, London SW7 2AZ (United Kingdom)

    2010-07-15

    Using the linearized Vlasov-Maxwell model, the polarization tensor for a weakly magnetized electron plasma is derived. For isotropic relativistic Maxwellian velocity distribution function, dispersion relations are obtained for both parallel and perpendicular propagations. The integrals (called Meijer G functions) that arise due to relativistic effects are examined in various limits and dispersion relations are derived for the nonrelativistic, weakly, strongly, and ultrarelativistic Maxwellian velocity distributions. It is generally observed that the propagation domains of the modes are enlarged as one proceeds from the nonrelativistic to the highly relativistic regime. Resultantly, due to the relativistic effects, the Whistler mode is suppressed in the R-wave, the nonpropagation band of X-mode is reduced, and the X-mode itself approaches the O-mode. Further, the results derived in the ultra- and nonrelativistic limits found to be in agreement with the earlier calculations [G. Abbas et al. Phys. Scr. 76, 649 (2007); F. F. Chen, Introduction to Plasma Physics and Controlled Fusion (Plenum, New York, 1984), Vol. 1].

  8. The interplay of Kappa and core populations in the solar wind: Electromagnetic electron cyclotron instability

    NASA Astrophysics Data System (ADS)

    Lazar, M.; Poedts, S.; Schlickeiser, R.

    2014-12-01

    Recently, a realistic parameterization was proposed for the kinetic anisotropy and the resulting instabilities in the solar wind plasma. This parameterization is based on observations of the particle velocity distribution, which always comprises a Maxwellian population at low energies, viz. the core, and a suprathermal halo in the tail of the distribution which is best described by the Kappa (power law) models. The cyclotron instability, driven by an anisotropic electron halo, was found to be inhibited by the finite thermal spread in the core, and this effect is highly dependent on the halo-core relative density. In this paper, the interplay between the Kappa and Maxwellian populations is further investigated for more complex (less idealized) situations when both the core and halo temperatures are anisotropic. Growth of this instability is markedly stimulated by the core anisotropy. The wave numbers that are stable for an isotropic core become unstable even for small anisotropies of this population. Just a modest increase of the core anisotropy from Ac=T?/T?=1.2 to 2 causes the growth rates to enhance by 1 order of magnitude, and the range of unstable wave numbers to extend considerably. When the anisotropies in the core and halo are comparable, the growth rate exhibits two distinct peaks, the first driven by the halo at lower wave numbers and the second driven by the core. However, the first peak is inhibited by the suprathermal populations, while the second peak is sustained, suggesting a more intricate connection between the core and Kappa populations.

  9. Electron CoolingElectron Cooling Sergei Nagaitsev

    E-print Network

    Fermilab

    Coulomb's law for two point charges Ohm's law or similar law relating voltage and current Liouville by classical physics laws: Conservation of energy and momentum Ampère's law: dF=Idl?B Maxwell's equations

  10. A modified Bitter-type electromagnet and control system for cold atom experiments

    SciTech Connect

    Luan, Tian; Zhou, Tianwei; Chen, Xuzong, E-mail: xuzongchen@pku.edu.cn [School of Electronics Engineering and Computer Science, Peking University, Beijing 100871 (China)] [School of Electronics Engineering and Computer Science, Peking University, Beijing 100871 (China); Ma, Zhaoyuan, E-mail: zyma@siom.cas.cn [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)] [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

    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}.

  11. Contributions to the second workshop on medium energy electron cooling - MEEC96

    SciTech Connect

    MacLachlan, J. [ed.

    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.

  12. Combining nanocalorimetry and dynamic transmission electron microscopy for in situ characterization of materials processes under rapid heating and cooling

    SciTech Connect

    Grapes, Michael D., E-mail: mgrapes1@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); LaGrange, Thomas; Reed, Bryan W.; Campbell, Geoffrey H. [Condensed Matter and Materials Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Friedman, Lawrence H.; LaVan, David A., E-mail: david.lavan@nist.gov [Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Weihs, Timothy P., E-mail: weihs@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    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 ns500 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/s10{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.

  13. 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.

  14. 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.

  15. The cooling of particle beams

    SciTech Connect

    Sessler, A.M.

    1994-10-01

    A review is given of the various methods which can be employed for cooling particle beams. These methods include radiation damping, stimulated radiation damping, ionization cooling, stochastic cooling, electron cooling, laser cooling, and laser cooling with beam coupling. Laser Cooling has provided beams of the lowest temperatures, namely 1 mK, but only for ions and only for the longitudinal temperature. Recent theoretical work has suggested how laser cooling, with the coupling of beam motion, can be used to reduce the ion beam temperature in all three directions. The majority of this paper is devoted to describing laser cooling and laser cooling with beam coupling.

  16. Effects of high-energy particle showers on the embedded front-end electronics of an electromagnetic calorimeter for a future lepton collider

    E-print Network

    The CALICE Collaboration

    2011-06-03

    Application Specific Integrated Circuits, ASICs, similar to those envisaged for the readout electronics of the central calorimeters of detectors for a future lepton collider have been exposed to high-energy electromagnetic showers. A salient feature of these calorimeters is that the readout electronics will be embedded into the calorimeter layers. In this article it is shown that interactions of shower particles in the volume of the readout electronics do not alter the noise pattern of the ASICs. No signal at or above the MIP level has been observed during the exposure. The upper limit at the 95% confidence level on the frequency of faked signals is smaller than 1x10^{-5} for a noise threshold of about 60% of a MIP. For ASICs with similar design to those which were tested, it can thus be largely excluded that the embedding of the electronics into the calorimeter layers compromises the performance of the calorimeters.

  17. Weight and power considerations for the design of a cryogenically cooled HTS electronic system

    Microsoft Academic Search

    M Nisenoff

    1996-01-01

    Much progress has been reported on the fabrication of high temperature superconducting (HTS) electronic devices, circuits and systems. In some of these reports, comparisons have been made between the electrical behavior of HTS components and their equivalent semiconductor counterparts. Unfortunately, in almost all cases, the comparisons have been made at the device or circuit level. In an operational system, the

  18. The electronic origin of the ??* absorption of amino coumarins studied in a supersonically cooled free jet

    NASA Astrophysics Data System (ADS)

    Ernsting, Niko P.; Asimov, Mustafo; Schfer, Fritz P.

    1982-09-01

    Several coumarins, both with "free" and "rigidized" amino groups, were studied by spectroscopy in a supersonic expansion of argon. The lowest vibronic band for the ?? * electronic excitation was found to be displaced by several hundred cm -1 to the blue from the symmetric position between the corresponding hot vapour absorption and emission bands, suggesting a negligible Franck-Condon overlap for the 00 transition.

  19. PHYSICS 417. Electromagnetism. Lecturer: Tim Gorringe.

    E-print Network

    MacAdam, Keith

    PHYSICS 417. Electromagnetism. Lecturer: Tim Gorringe. Office: CP273. Phone: 257-8740. Textbook: Electromagnetic Fields, R. Wangsness, 2nd Ed. Web page www.pa.uky.edu/gorringe/phy417/index.html Class hours: MWF-semester sequence on electromagnetic theory. 1 Course Objectives. The electromagnetic field binds electrons

  20. Assessment of Thermal Control Technologies for Cooling Electric Vehicle Power Electronics

    Microsoft Academic Search

    Thomas Abraham; Kevin Bennion; Desikan Bharathan; Sreekant Narumanchi; Michael O'Keefe

    The U.S. Department of Energy (DOE) FreedomCAR Program's technical targets for the electric traction system (power electronics and electric machines) of advanced vehicles require significant reductions in volume, weight, and cost while also meeting performance and 15 year life requirements (1). The performance of the semiconductor switches and diodes, the ripple-current capability of the capacitors, and the life of the

  1. A multi-band, multi-level, multi-electron model for efficient FDTD simulations of electromagnetic interactions with semiconductor quantum wells

    E-print Network

    Ravi, Koustuban; Ho, Seng-Tiong

    2015-01-01

    We report a new computational model for simulations of electromagnetic interactions with semiconductor quantum well(s) (SQW) in complex electromagnetic geometries using the finite difference time domain (FDTD) method. The presented model is based on an approach of spanning a large number of electron transverse momentum states in each SQW sub-band (multi-band) with a small number of discrete multi-electron states (multi-level, multi-electron). This enables accurate and efficient two dimensional (2-D) and 3-D simulations of nanophotonic devices with SQW active media. The model includes the following features: (1) Optically induced interband transitions between various SQW conduction and heavy-hole or light-hole sub-bands are considered. (2) Novel intra sub-band and inter sub-band transition terms are derived to thermalize the electron and hole occupational distributions to the correct Fermi-Dirac distributions. (3) The terms in (2) result in an explicit update scheme which circumvents numerically cumbersome ite...

  2. Spectroscopy and electronic structure of jet-cooled NiPd and PdPt

    NASA Astrophysics Data System (ADS)

    Taylor, Scott; Spain, Eileen M.; Morse, Michael D.

    1990-03-01

    Resonant two-photon ionization spectroscopy of jet-cooled NiPd and PdPt has revealed a dense vibronic spectrum for NiPd and a much more sparse spectrum for PdPt. Four vibrational progressions have been identified for NiPd, and three have been located for PdPt. High resolution investigations of NiPd have established a ground state bond length of r?0 =2.2420.005 with ??=2. The observed spectra have been used to bracket the ionization potentials, giving IP(NiPd)=7.180.76 eV and IP(PdPt)=8.270.38 eV. In contrast to previous work on Ni2, NiPt, and Pt2, no abrupt onset of rapid predissociation is observed for either NiPd or PdPt. A discussion of this result in terms of the expected potential energy curves for the palladium-containing diatomics is presented, which when combined with the frequencies of the highest energy vibronic bands observed yields estimates of D0(NiPd)?1.46 eV and D0(PdPt)?1.98 eV. The lack of observable vibronic transitions in Pd2 above 11 375 cm-1 places D0(Pd2) below 1.41 eV, in agreement with Knudsen effusion mass spectrometry. Finally a comparison of the platinum group dimers and the coinage metal dimers is given, demonstrating the increasing importance of d-orbital contributions to the bonding in the platinum group dimers as one moves down the periodic table. The anomalous behavior of the palladium-containing diatomics is also discussed in terms of the highly stable 4d105s0, 1S0 ground state of atomic palladium.

  3. Neutrino Signal of Electron-Capture Supernovae from Core Collapse to Cooling

    SciTech Connect

    Huedepohl, L.; Mueller, B.; Janka, H.-T.; Marek, A. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, D-85748 Garching (Germany); Raffelt, G. G. [Max-Planck-Institut fuer Physik, Werner-Heisenberg-Institut, Foehringer Ring 6, D-80802 Muenchen (Germany)

    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.

  4. Neutrino signal of electron-capture supernovae from core collapse to cooling.

    PubMed

    Hdepohl, L; Mller, 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 ?{e} and ?{?,?} very similar, ruling out the neutrino-driven wind as r-process site. We also discuss consequences for neutrino flavor oscillations. PMID:20867357

  5. 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.

  6. CFD study of liquid-cooled heat sinks with microchannel flow field configurations for electronics, fuel cells, and concentrated solar cells

    Microsoft Academic Search

    Bladimir Ramos-Alvarado; Peiwen Li; Hong Liu; Abel Hernandez-Guerrero

    2011-01-01

    A study of the heat transfer performance of liquid-cooled heat sinks with conventional and novel micro-channel flow field configurations for application in electronic devices, fuel cells, and concentrated solar cells is presented in this paper. The analyses were based on computations using the CFD software ANSYS FLUENT. The flow regime in heat sinks is constrained to laminar flow in the

  7. Search for CP-violation in the Lepton Sector: Electron Electric Dipole Moment (EDM) Experiments with Laser-Cooled Cesium Atoms

    Microsoft Academic Search

    Harvey Gould

    2004-01-01

    I describe our current and future experiments to search for an electron EDM, using a fountain of laser-cooled and launched Cs atoms. High sensitivity comes from long interaction times, multiple quantum transitions, and electrostatic focusing. Immunity to systematic effects comes from electric field quantization, the removal of static magnetic fields, the use of slow atoms, and the fountain geometry. A

  8. Laser cooling and trapping of atomic particles. (Latest citations from the NTIS data base). Published Search

    SciTech Connect

    Not Available

    1992-04-01

    The bibliography contains citations concerning theory and experiments on laser cooling and laser trapping of neutral atoms and atomic ions. Atoms and ions are cooled by laser radiation pressure to very low Kelvin temperatures and confined in electromagnetic traps of very high density. Atomic particles discussed include sodium atoms, mercury ions, beryllium ions, magnesium ions, and hydrogen. Applications for high performance spectroscopy, atomic clocks, microwave and optical frequency standards, relativistic neutral particle beam weapons, exotic fuels, cooling of electron beams, and space propulsion are examined. (Contains a minimum of 151 citations and includes a subject term index and title list.)

  9. Laser cooling and trapping of atomic particles. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    Not Available

    1994-12-01

    The bibliography contains citations concerning theory and experiments on laser cooling and laser trapping of neutral atoms and atomic ions. Atoms and ions are cooled by laser radiation pressure to very low Kelvin temperatures and confined in electromagnetic traps of very high density. Atomic particles cover sodium atoms, mercury ions, beryllium ions, magnesium ions, and hydrogen. Citations discuss applications in high performance spectroscopy, atomic clocks, microwave and optical frequency standards, relativistic neutral particle beam weapons, exotic fuels, cooling of electron beams, and space propulsion. (Contains a minimum of 204 citations and includes a subject term index and title list.)

  10. Laser cooling and trapping of atomic particles. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    NONE

    1994-02-01

    The bibliography contains citations concerning theory and experiments on laser cooling and laser trapping of neutral atoms and atomic ions. Atoms and ions are cooled by laser radiation pressure to very low Kelvin temperatures and confined in electromagnetic traps of very high density. Atomic particles cover sodium atoms, mercury ions, beryllium ions, magnesium ions, and hydrogen. Citations discuss applications in high performance spectroscopy, atomic clocks, microwave and optical frequency standards, relativistic neutral particle beam weapons, exotic fuels, cooling of electron beams, and space propulsion. (Contains a minimum of 185 citations and includes a subject term index and title list.)

  11. Liquid nitrogen cooled integrated power electronics module with high current carrying capability and lower on resistance

    NASA Astrophysics Data System (ADS)

    Ye, Hua; Lee, Changwoo; Simon, Randy W.; Haldar, Pradeep; Hennessy, Michael J.; Mueller, Eduard K.

    2006-11-01

    This letter presents the development of high-performance integrated cryogenic power modules, where both driver components and power metal-oxide semiconductor field-effect transistors are integrated in a single package, to be used in a 50kW prototype cryogenic inverter operating at liquid nitrogen temperature. The authors have demonstrated a compact high-voltage, cryogenic integrated power module that exhibited more than 14 times improvement in on-resistance and continuous current carrying capability exceeding 40A. The modules are designed to operate at liquid nitrogen temperature with extreme thermal cycling. The power electronic modules are necessary components that provide control and switching for second generation, yttrium barium copper oxide-based high temperature superconductor devices including cables, motors, and generators.

  12. 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

  13. Electronic Spectroscopy of Jet-Cooled Triatomics and Cumulenes: Hydrogen Sulfide, Carbon Disulfide, Allene, and Carbon Suboxide.

    NASA Astrophysics Data System (ADS)

    Lantz, Kathleen O'brien

    The primary emphasis of this dissertation is to investigate the photoreactivity of a few small polyatomic molecules in their excited electronic states in the vacuum ultraviolet region. In this thesis, there are two types of polyatomics explored; triatomics (CS_2 and H_2S) and cumulenes (rm C_3O_2 and rm C_3H_4). The excited electronic states whose photoreactivity is investigated are the ^1Pi_{rm g} electronic state of CS_2 (1800-1650 A), the first electronic band of hydrogen sulfide (2300 -1700 A), the ^1{rm B}_2 electronic state of allene, H_2 C=C=CH_2, and a moderately strong structured band of carbon suboxide, O=C=C=C=O, centered at 1780 A. To understand the photoreactivity of a molecule, it is ideal to characterize the relevant potential energy surfaces and interpret the dynamics along these surfaces from reactant to products. This requires the collaboration of experimentalist and theoreticians. The allure of triatomics is that they are the simplest of polyatomic molecules having only three or four vibrational degrees of freedom. In practice, even triatomics have eluded a detailed analysis of their photoreactivity due to the complexity of the dynamics occurring on coupled multiple surfaces. Cumulenes are much more complex systems consisting of repetitive double bonds. These rigid molecules give rise to very low vibrational frequencies in the bending and torsional modes, which makes these molecules interesting prototypes for studying the effects of low frequency motions on the dynamics of the photodissociation. In this work, direct absorption spectroscopy will be used coupled with a supersonic expansion of the molecules under investigation. Direct absorption spectroscopy provides important information on the early time dynamics of the molecules' photodissociation toward products. A supersonic expansion of the sample reduces spectral congestion by cooling internal rotational and vibrational degrees of freedom of the molecules which facilitates the analysis of the spectrum. Additionally, at higher pressures supersonic expansions promote clustering which can be used as a tool to distinguish Rydberg and valence states. Direct absorption spectroscopy complements recent and previous experimental and theoretical work towards an understanding of the spectroscopy and dynamics of these two triatomics and cumulenes.

  14. 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.

  15. Observation of the A-X Electronic Transition of the Jet-Cooled Methyl Peroxy Radical by High Resolution CRDS

    NASA Astrophysics Data System (ADS)

    Dupr, Patrick; Wu, Shenghai; Rupper, Patrick; Miller, Terry

    2007-03-01

    Reactive intermediates are of crucial importance both for combustion and atmospheric chemistry. By using our new home made Fourier Transform limited (10--30 MHz) Ti:Sa laser source we have probed the vibrationless level of the first electronic state (in the near-IR range) of both CH3OO and CD3OO radical species. The radicals are formed inside a Ne/He/O2/CH3I plasma created by a DC or a RF electrical discharge. The supersonic jet expansion necessary for the rotational cooling (20,) is obtained by a pulsed slit nozzle (50x0.5,^2). The near-IR radiation, obtained by Stimulated Raman Scattering (SRS) is injected inside a high finesse cavity. A sensitivity of the order of 20x10-9,pass/?Hz is currently obtained. Spectrum with a resolution 350, for CD3OO clearly shows rotational and spin-rotation structure with effects of the internal methyl group rotation possibly evolved.

  16. 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.

  17. 1578 IEEEJOURNAL OF QUANTUMELECTRONICS.VOL.QE-23, NO. 9. SEPTEMBER 1987 Free-Electron Lasers with Electromagnetic Standing

    E-print Network

    Wurtele, Jonathan

    1578 IEEEJOURNAL OF QUANTUMELECTRONICS.VOL.QE-23, NO. 9. SEPTEMBER 1987 Free-Electron Lasers of the electroniagnetic standing wave wiggler for free-electron lasers (FEL's) is conducted for both circular and linear codes developed for conventional FEL's. I.INTRODUCTION IN a free-electron laser (FEL), thecoherent

  18. Refrigerant directly cooled capacitors

    DOEpatents

    Hsu, John S. (Oak Ridge, TN); Seiber, Larry E. (Oak Ridge, TN); Marlino, Laura D. (Oak Ridge, TN); Ayers, Curtis W. (Kingston, TN)

    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.

  19. Physical principles of the amplification of electromagnetic radiation due to negative electron masses in a semiconductor superlattice

    NASA Astrophysics Data System (ADS)

    Shorokhov, A. V.; Pyataev, M. A.; Khvastunov, N. N.; Hyart, T.; Kusmartsev, F. V.; Alekseev, K. N.

    2015-02-01

    In a superlattice placed in crossed static electric and magnetic fields, under certain conditions, the inversion of electron population can appear at which the average energy of electrons is above the middle of the mini-band and the effective mass of the electron is negative. This is the implementation of the negative effective mass amplifier and generator (NEMAG) in the superlattice. It can result in the amplification and generation of terahertz radiation even in the absence of negative differential conductivity.

  20. Electromagnetics from Simulation to Optimal Design

    E-print Network

    Lang, Annika

    1 Electromagnetics from Simulation to Optimal Design Christian Hafner Laboratory for Electromagnetic Fields and Microwave Electronics (IFH) ETH Zurich (Switzerland) Lab: http://www.ifh.ee.ethz.ch COG 23, 2013 #12;2 IFH courses · Advanced engineering electromagnetics (Leuchtmann, start spring 2014

  1. A technology that squeezes electromagnetic waves

    E-print Network

    Atwater, Harry

    A technology that squeezes electromagnetic waves into minuscule structures may yield a new and manipulate visible light and other electromagnetic waves--could someday replace electronic circuits in micro plasmons with the same frequency as the outside electromagnetic waves but with a much shorter wavelength

  2. Electromagnetic waves

    NSDL National Science Digital Library

    David P. Stern

    2004-09-23

    These pages, part of From Stargazers to Starships, explain electromagnetic waves and sunlight. Information inlcudes physiological and spectral color, spectral lines, the electromagnetic field work by Maxwell, the discovery of radio waves by Hertz, and photons and Einsteins relation. Stargazers also has detailed lesson plans accompanying these sections.

  3. 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)

  4. Electromagnetic Wave

    NSDL National Science Digital Library

    Fendt, Walter

    This simulation shows a plane polarized electromagnetic wave propagating in positive x direction. The vectors of the electric field (red) are parallel to the y axis, the vectors of the magnetic field (blue) are parallel to the z axis. This applet illustrates the behavior of the fields in electromagnetic waves. This is part of a large collection of physics applets available in several languages.

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

    SciTech Connect

    Esmaeilzadeh, Mahdi; Taghavi, Amin [Department of Physics, Iran University of Science and Technology, Narmak, Tehran 16844 (Iran, Islamic Republic of)

    2011-05-15

    Nasr and Hasanbeigi in their comment [Phys. Plasmas 17, 093103 (2010)] have claimed that, in our recent paper [Phys. Plasmas 17, 093103 (2010)], incorrect initial conditions have been used based on dispersion relation (or normalized electromagnetic wave frequency {omega}{sub w}) and mean axial velocity {beta}{sub b}. We use a self-consistent method to calculate more accurate values of {omega}{sub w} and {beta}{sub b} and show that all results presented in our recent paper are correct.

  6. Evolution of electromagnetic electron holes in the generation process of whistler-mode chorus emissions: A particle simulation study

    NASA Astrophysics Data System (ADS)

    Hikishima, M.; Omura, Y.

    2011-12-01

    Recent particle simulations have successfully reproduced the generation process of whistler-mode rising-tone emissions like chorus emissions [1]. Chorus emissions are interpreted as triggered emissions by a coherent whistler-mode wave excited at a constant frequency via the linear cyclotron resonance instability driven by temperature anisotropy of energetic electrons. By injecting a triggering wave artificially from the magnetic equator, we find that triggering waves with different wave amplitudes result in rising-tone emissions with almost the same frequency sweep rate and saturation level. We find formation of an electron hole in the velocity phase space near the magnetic equator. The electron hole is asymmetric in the phase because of the frequency variation of the triggered emissions, which gives the inhomogeneity ratio S -0.4 as assumed in the nonlinear wave growth theory [2]. The depletion of resonant electrons due to formation of electron holes moves progressively toward the core part of the distribution function at higher pitch angles. At the large perpendicular velocity, we find formation of an electron island rather than an electron hole. A larger number of resonant electrons are trapped at high perpendicular velocities at some distance away from the equator. Because of the decreasing parallel velocity and the acceleration in the perpendicular direction, the resonant electrons trapped by the wave appear forming an island in the velocity phase space. The trapped electrons receive energy from the wave, while untrapped resonant electrons lose energy to the wave propagating away from the equator. The balance between the electron hole and the electron island in the velocity phase space determines the saturation of chorus emissions. [1] Hikishima, M., Y. Omura, and D. Summers (2010), Self-consistent particle simulation of whistler mode triggered emissions, J. Geophys. Res., 115, A12246, doi:10.1029/2010JA015860. [2] Omura, Y., Y. Katoh, and D. Summers (2008), Theory and simulation of the generation of whistler-mode chorus, J. Geophys. Res., 113, A04223, doi:10.1029/2007JA012622.

  7. Electromagnetic effects on geodesic acoustic modes

    SciTech Connect

    Bashir, M. F., E-mail: frazbashir@yahoo.com [Salam Chair in Physics, G. C. University Lahore, Katchery Road, Lahore 54000 (Pakistan); Department of Physics, G. C. University Lahore, Katchery Road, Lahore 54000 (Pakistan); Smolyakov, A. I. [University of Saskatchewan, 116 Science Place, Saskatoon S7N 5E2 (Canada); Institute of Tokamak Physics, NRC Kurchatov Institute, 123182 Moscow (Russian Federation); Elfimov, A. G. [Institute of Physics, University of So Paulo, So Paulo 05508-090 (Brazil); Melnikov, A. V. [Institute of Tokamak Physics, NRC Kurchatov Institute, 123182 Moscow (Russian Federation); National Research Nuclear University MEPhI, 115409, Moscow (Russian Federation); Murtaza, G. [Visiting Professor, Department of Physics, Quaid-e-Azam University, Islamabad (Pakistan)

    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 ?{sub e}, the safety factor q, and the temperature ratio ? on GAM dispersion are analyzed.

  8. "Electromaglev" ("active-maglev") - magnetic levitation of a superconducting disk with a DC field generated by electromagnets. Part 4: theoretical and experimental results on supercurrent distributions in field-cooled YBCO disks

    NASA Astrophysics Data System (ADS)

    Tsuda, Makoto; Lee, Haigun; Noguchi, So; Iwasa, Yukikazu

    We present Part 4 results of a comprehensive theoretical study of an "electromaglev" system, in which a high-temperature superconducting bulk YBCO sample is levitated stably in a DC magnetic field generated by magnet system underneath the floating object. An electromagnetic analysis, based on a three-dimensional finite element technique (FEM) applied to the current vector potential method, has been developed to determine the supercurrent distribution in a field-cooled (and hence trapped-flux) YBCO disk that levitates stably in a magnetic field generated by the magnet system. The supercurrent distribution thus determined was in turn used to compute trapped-flux-induced field profiles of the disk and predict a "levitation current" in the magnet system at which the disk, initially resting on a support plate, begins to levitate. Agreement between computed field profiles and levitation currents and those measured in the experiment was excellent, validating the analysis itself and the method used to derive solutions. The analysis demonstrates that the supercurrent distribution within a trapped-flux disk is far more complicated than that derived from the Bean model for a long cylinder under a uniform axial magnetic field. It is used for a parametric study of the effects of disk dimensions (radius, thickness, radius/thickness ratio) and trapped-flux strength on supercurrent distribution and lift-to-weight ratio. The magnitude of the Br component generated by the magnet system is very important for lift and it is shown that thinner disks rather than thicker disks can improve lift-to-weight ratio. Because accuracy of the analysis is disk-size independent, small disks are time-efficient for performing the analysis.

  9. Cooling at the quantum limit and RF refrigeration

    E-print Network

    Fominov, Yakov

    Cooling at the quantum limit and RF refrigeration Jukka Pekola Low Temperature Laboratory, Helsinki (electromagnetic) heat transport Cooling at the quantum limit: experiments RF refrigeration in a single as a refrigerator Optimum cooling power is reached at V 2/e: Cooling power of a NIS junction: Temperature TN

  10. 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.

  11. All-optical NMR in semiconductors provided by resonant cooling of nuclear spins interacting with electrons in the resonant spin amplification regime

    NASA Astrophysics Data System (ADS)

    Zhukov, E. A.; Greilich, A.; Yakovlev, D. R.; Kavokin, K. V.; Yugova, I. A.; Yugov, O. A.; Suter, D.; Karczewski, G.; Wojtowicz, T.; Kossut, J.; Petrov, V. V.; Dolgikh, Yu. K.; Pawlis, A.; Bayer, M.

    2014-08-01

    Resonant cooling of different nuclear isotopes manifested in optically induced nuclear magnetic resonances (NMR) is observed in n-doped CdTe/(Cd,Mg)Te and ZnSe/(Zn,Mg)Se quantum wells and for donor-bound electrons in ZnSe:F and GaAs epilayers. By time-resolved Kerr rotation used in the regime of resonant spin amplification, we can expand the range of magnetic fields where the effect can be observed up to nuclear Larmor frequencies of 170 kHz. The mechanism of the resonant cooling of the nuclear spin system is analyzed theoretically. The developed approach allows us to model the resonant spin amplification signals with NMR features.

  12. Neutrino-pair emission due to electron-phonon scattering in a neutron star crust: a reappraisal 1 This work was supported in part by Spanish Grant DGES PB97- 1432, and the Russian Foundation for Fundamental Research Grant 97-02-16501, and INTAS Grant 96-0659. 1

    Microsoft Academic Search

    L. B. Leinson

    1999-01-01

    The process of ??? radiation due to interaction of electrons with phonons in the crust of a cooling neutron star is studied with the consistent account of an electromagnetic coupling between electrons in the medium. The wavelength of radiated neutrinos and antineutrinos is typically much larger than the electron Debye screening distance in the medium, and therefore plasma polarization substantially

  13. 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.

  14. Electromagnetic fasteners

    DOEpatents

    Crane, Randolph W. (Idaho Falls, ID); Marts, Donna J. (Idaho Falls, ID)

    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.

  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. 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.

  17. Electromagnetic Fields

    MedlinePLUS

    ... off radio-frequency energy (RF), a form of electromagnetic radiation. Scientists need to do more research on this before they can say for sure. NIH: National Institute of Environmental Health Sciences

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

    Microsoft Academic Search

    C. W. Ayers; J. S. Hsu; K. T. Lowe

    The Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) has 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 electronics, is essential for the reliable operation of motors and power electronics. As part of a larger thermal management

  19. 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.

  20. Laser cooling and trapping of atomic particles. January 1970-September 1989 (Citations from the NTIS data base). Report for Jan 70-Sep 89

    SciTech Connect

    Not Available

    1989-11-01

    This bibliography contains citations concerning theory and experiments on laser cooling and laser trapping of neutral atoms and atomic ions. Atoms and ions are cooled by laser radiation pressure to very low Kelvin temperatures and confined in electromagnetic traps with very high density. Atomic particles discussed include sodium atoms, mercury ions, beryllium ions, magnesium ions, and hydrogen. Applications include high performance spectroscopy, atomic clocks, microwave and optical frequency standards, relativistic neutral particle beam weapons, exotic fuels, cooling of electron beams, and space propulsion. (Contains 97 citations fully indexed and including a title list.)

  1. 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.

  2. Comparison of SAR and induced current densities in adults and children exposed to electromagnetic fields from electronic article surveillance devices

    Microsoft Academic Search

    M. Martnez-Brdalo; A. Sanchis; A. Martn; R. Villar

    2010-01-01

    Electronic article surveillance (EAS) devices are widely used in most stores as anti-theft systems. In this work, the compliance with international guidelines in the human exposure to these devices is analysed by using the finite-difference time-domain (FDTD) method. Two sets of high resolution numerical phantoms of different size (REMCOM\\/Hershey and Virtual Family), simulating adult and child bodies, are exposed to

  3. Electron beam dynamics and self-cooling up to PeV level due to betatron radiation in plasma-based accelerators

    NASA Astrophysics Data System (ADS)

    Deng, Aihua; Nakajima, Kazuhisa; Liu, Jiansheng; Shen, Baifei; Zhang, Xiaomei; Yu, Yahong; Li, Wentao; Li, Ruxin; Xu, Zhizhan

    2012-08-01

    In plasma-based accelerators, electrons are accelerated by ultrahigh gradient of 1-100GV/m and undergo the focusing force with the same order as the accelerating force. Heated electrons are injected in a plasma wake and exhibit the betatron oscillation that generates synchrotron radiation. Intense betatron radiation from laser-plasma accelerators is attractive x-ray/gamma-ray sources, while it produces radiation loss and significant effects on energy spread and transverse emittance via the radiation reaction force. In this article, electron beam dynamics on transverse emittance and energy spread with considering radiation reaction effects are studied numerically. It is found that the emittance growth and the energy spread damping initially dominate and balance with radiative damping due to the betatron radiation. Afterward the emittance turns to decrease at a constant rate and leads to the equilibrium at a nanometer radian level with growth due to Coulomb scattering at PeV-level energies. A constant radiation loss rate RT=2/3 is found without regard to the electron beam and plasma conditions. Self-cooling of electron beams due to betatron radiation may guarantee TeV-range linear colliders and give hints on astrophysical ultrahigh-energy phenomena.

  4. Ultra-light and stable composite structure to support and cool the ATLAS pixel detector barrel electronics modules

    NASA Astrophysics Data System (ADS)

    Olcese, M.; Caso, C.; Castiglioni, G.; Cereseto, R.; Cuneo, S.; Dameri, M.; Gemme, C.; Glitza, K.-W.; Lenzen, G.; Mora, F.; Netchaeva, P.; Ockenfels, W.; Piano, E.; Pizzorno, C.; Puppo, R.; Rebora, A.; Rossi, L.; Thadome, J.; Vernocchi, F.; Vigeolas, E.; Vinci, A.

    2004-02-01

    The design of an ultra light structure, the so-called "stave", to support and cool the sensitive elements of the Barrel Pixel detector, the innermost part of the ATLAS detector to be installed on the new Large Hadron Collider at CERN (Geneva), is presented. Very high-dimensional stability, minimization of the material and ability of operating 10 years in a high radiation environment are the key design requirements. The proposed solution consists of a combination of different carbon-based materials (impregnated carbon-carbon, ultra high modulus carbon fibre composites) coupled to a thin aluminum tube to form a very light support with an integrated cooling channel. Our design has proven to successfully fulfil the requirements. The extensive prototyping and testing program to fully qualify the design and release the production are discussed.

  5. Electromagnetic effects on quasilinear turbulent particle transport

    SciTech Connect

    Eriksson, Annika; Weiland, Jan [Radio and Space Science, Chalmers University of Technology and EURATOM-VR Association, S-412 96 Goeteborg (Sweden)

    2005-09-15

    It is well known that a nonadiabatic part of the electron density response is needed for particle transport in tokamaks. Such main reactive effects are electron trapping and electromagnetic induction. Although electron trapping has been studied rather extensively, electromagnetic effects have hardly been studied at all although they are already included in transport codes. Here the electromagnetic effects have been analyzed and parameter studies have been performed, showing that an electromagnetic particle pinch may appear in the flat density regime, just as for the case of electron trapping although the conditions are more restrictive. The particle pinch is particularly sensitive to the direction of propagation of the eigenmode. The electromagnetic particle flux is found to be outward for modes propagating in the ion drift direction and inward for modes propagating in the electron drift direction. A pinch may be obtained rather close to the axis for International Thermonuclear Experimental Reactor simulation data.

  6. Is cooling still cool?

    PubMed

    Subramaniam, Ashwin; Tiruvoipati, Ravindranath; Botha, John

    2015-03-01

    Therapeutic hypothermia (TH), where patients are cooled to between 32C and 36C for a period of 12-24 hours and then gradually rewarmed, may reduce the risk of ischemic injury to cerebral tissue following a period of insufficient blood flow. This strategy of TH could improve mortality and neurological function in patients who have experienced out-of-hospital cardiac arrest (OOHCA). The necessity of TH in OOHCA was challenged in late 2013 by a fascinating and potentially practice changing publication, which found that targeting a temperature of 36C had similar outcomes to cooling patients to 33C. This article reviews the current literature and summarizes the uncertainties and questions raised when considering cooling of patients at risk of hypoxic brain injury. Irrespective of whether TH or targeted temperature management is deployed in patients at risk of hypoxic brain injury, it would seem that avoiding hyperpyrexia is important and that a more rigorous approach to neurological evaluation is mandated. PMID:25423577

  7. 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.

  8. Electromagnetic Theory 1 /56 Electromagnetic Theory

    E-print Network

    Bicknell, Geoff

    Electromagnetic Theory 1 /56 Electromagnetic Theory Summary: · Maxwell's equations · EM Potentials · Equations of motion of particles in electromagnetic fields · Green's functions · Lienard-Weichert potentials · Spectral distribution of electromagnetic energy from an arbitrarily moving charge #12;Electromagnetic

  9. Magnetism and Electromagnetism

    NSDL National Science Digital Library

    Kuphaldt, Tony R.

    All About Circuits is a website that ??provides a series of online textbooks covering electricity and electronics.? Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Magnetism and Electromagnetism, is the fourteenth chapter in Volume I ?? Direct Current. A few of the topics covered in this chapter include: Permanent magnets; Electromagnetic induction; and Mutual inductance. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

  10. Electromagnetic Signals from Bacterial DNA

    E-print Network

    A. Widom; J. Swain; Y. N. Srivastava; S. Sivasubramanian

    2012-02-09

    Chemical reactions can be induced at a distance due to the propagation of electromagnetic signals during intermediate chemical stages. Although is is well known at optical frequencies, e.g. photosynthetic reactions, electromagnetic signals hold true for muck lower frequencies. In E. coli bacteria such electromagnetic signals can be generated by electric transitions between energy levels describing electrons moving around DNA loops. The electromagnetic signals between different bacteria within a community is a "wireless" version of intercellular communication found in bacterial communities connected by "nanowires". The wireless broadcasts can in principle be of both the AM and FM variety due to the magnetic flux periodicity in electron energy spectra in bacterial DNA orbital motions.

  11. 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.

  12. Electromagnetic Circuits

    E-print Network

    Milton, Graeme W

    2008-01-01

    The electromagnetic analog of an elastic spring-mass network is constructed. These are called electromagnetic circuits and linear electrical circuits correspond to a subclass of them. They consist of thin triangular magnetic components joined at the edges by cylindrical dielectric components. Some of the edges can be terminal edges to which electric fields are applied. The response is measured in terms of the free currents associated with the terminal edges. The relation between the terminal electric fields and the terminal free currents is governed by a symmetric complex matrix W. In the case where all the terminal edges are disjoint, and the frequency is fixed, a complete characterization is obtained of all possible response matrices W, both in the lossless and lossy cases. There are also dual electromagnetic circuits consisting of thin triangular dielectric components joined at the edges by cylindrical magnetic components

  13. Gravitation and Electromagnetism

    E-print Network

    B. G. Sidharth

    2001-06-16

    The realms of gravitation, belonging to Classical Physics, and Electromagnetism, belonging to the Theory of the Electron and Quantum Mechanics have remained apart as two separate pillars, inspite of a century of effort by Physicists to reconcile them. In this paper it is argued that if we extend ideas of Classical spacetime to include in addition to non integrability non commutavity also, then such a reconcilation is possible.

  14. Electromagnetic Geometry

    E-print Network

    M. Novello; F. T. Falciano; E. Goulart

    2011-11-08

    We show that Maxwell's electromagnetism can be mapped into the Born-Infeld theory in a curved space-time, which depends only on the electromagnetic field in a specific way. This map is valid for any value of the two lorentz invariants $F$ and $G$ confirming that we have included all possible solutions of Maxwell's equations. Our result seems to show that specifying the dynamics and the space-time structure of a given theory can be viewed merely as a choice of representation to describe the physical system.

  15. Electromagnet Lesson

    NSDL National Science Digital Library

    Orzali, Joe

    This hands-on classroom activity will help students understand the connections between magnets and electricity generation. The learning cycle planner includes an exploration phase with a hands-on activity and a suggested video. The concept development phase suggests showing the film "Who Killed the Electric Car?" The main part of this learning unit is the electromagnet lesson, which is a two day small group activity in which students will create an electromagnet. This document may be downloaded in PDF file format; student worksheets are included.

  16. Enhanced Conversion of Thermal Electron Bernstein Waves to the Extraordinary Electromagnetic Mode on the National Spherical Torus Experiment (NSTX)

    SciTech Connect

    G. Taylor; P.C. Efthimion; B. Jones; B.P. LeBlanc; J.R. Wilson; J.B. Wilgen; G.L. Bell; T.S. Bigelow; R. Maingi; D.A. Rasmussen; R.W. Harvey; A.P. Smirnov; F. Paoletti; S.A. Sabbagh

    2002-10-15

    A four-fold increase in the conversion of thermal electron-Bernstein waves (EBW) to the extraordinary mode (X-mode) was measured when the density scale length (L subscript ''n'') was progressively shortened by a local Boron nitride limiter in the scrape-off of an ohmically heated National Spherical Torus Experiment (NSTX) plasma [M. Ono, S. Kaye, M. Peng, et al., Proceedings 17th IAEA Fusion Energy Conference (IAEA, Vienna, Austria, 1999), Vol. 3, p. 1135]. The maximum conversion efficiency approached 50% when L subscript ''n'' was reduced to 0.7 cm, in agreement with theoretical predictions that used locally measured L subscript ''n''. Calculations indicate that it is possible to establish L subscript ''n'' < 0.3 cm with a local limiter, a value predicted to attain approximately 100% EBW conversion to the X-mode in support of proposed EBW heating and current drive scenarios.

  17. Influence of an intense pulsed electromagnetic field on nonresonant scattering of a photon by an electron for the nonrelativistic energy

    NASA Astrophysics Data System (ADS)

    Nedoreshta, Vitaly N.; Roshchupkin, Sergei P.; Voroshilo, Alexey I.

    2013-03-01

    The theory of nonresonant scattering of a photon by an electron in the field of an intense pulsed light wave is developed. The approximation when a pulse width is considerably greater than the characteristic time of wave oscillation is considered. The nonresonant kinematic region is determined. The general relativistic expression for the nonresonant cross-section is derived for the range of the external field intensities if ? 0 ? 1, ?0 2 ? 1 (see Eq. (12)) is valid. The obtained differential cross-section of the process has form of a sum over partial differential cross-sections. Each of them corresponds to the process with emission (absorption) of a certain number of wave photons. It is shown, that for nonrelativistic energy the cross-section summed over all possible partial processes differs considerably from the cross-section of Compton scattering if the external field is absent and may exceed the latter over than 200%.

  18. Novel electromagnetic materials from functionalized structures

    NASA Astrophysics Data System (ADS)

    Xiao, Xiao

    Materials, exhibiting the novel electromagnetic responses those may not be found in nature, have the potential to manipulate the electromagnetic field passing through them. Consequently, these materials promise a number of applications, such as highly sensitive sensor, superlenses, high-gain antennas and electromagnetic wave cloaking. In the literature we would investigate various electromagnetic materials composed from functionalized structures (components). The novel electromagnetic materials can be photonic crystals, which are composed of the periodic dielectric or metallic structures. The propagation of the electromagnetic wave in photonic crystals is affected in the same way as the electrons propagating in the periodic potential in solid. We demonstrated that the photonic crystals can be used as a tool to tune the birefringence of the electromagnetic field. Metamaterials, which are composed of the artificial structures exhibiting strong local resonances, are also a kind of novel electromagnetic materials. The strong local resonance can squeeze the wavelength of the incoming electromagnetic field to the subwavelength region (i.e. superlenses) and revise the effective electromagnetic response of the materials (i.e. the negative indexes). For metamaterials we focus on the Plasmonic metamaterials in the thesis: we would show that these materials could be used to guide electromagnetic wave or introduce various kinds of extraordinary transmissions, both of which, of course, are achieved at subwavelength region. Moreover, the novel electromagnetic materials can be even the topological insulators, whose non-trivial electronic surface states can have extraordinary responses under the electromagnetic field. These non-trivial quantum hall surface states can introduce the mode conversion between different electromagnetic modes on the surfaces of the topological insulators and thus modify the propagation properties of the electromagnetic field through them. We would demonstrate that the non-trivial surface states of the topological insulators could modify the coherence of the thermal radiation from them.

  19. ECE 341: Electromagnetic Fields I EM devices and systems

    E-print Network

    Schumacher, Russ

    in material media - Electromagnetic induction - Inductance - Magnetic energy Applications: - ElectronicsECE 341: Electromagnetic Fields I EM devices and systems - Can compute and analyze potentials compositions - Can evaluate capacitance, inductance, resistance, and conductance of EM structures - Understands

  20. Electromagnetic Survey

    USGS Multimedia Gallery

    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....

  1. Electromagnetic Survey

    USGS Multimedia Gallery

    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...

  2. 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.

  3. Comparison of SAR and induced current densities in adults and children exposed to electromagnetic fields from electronic article surveillance devices

    NASA Astrophysics Data System (ADS)

    Martnez-Brdalo, M.; Sanchis, A.; Martn, A.; Villar, R.

    2010-02-01

    Electronic article surveillance (EAS) devices are widely used in most stores as anti-theft systems. In this work, the compliance with international guidelines in the human exposure to these devices is analysed by using the finite-difference time-domain (FDTD) method. Two sets of high resolution numerical phantoms of different size (REMCOM/Hershey and Virtual Family), simulating adult and child bodies, are exposed to a 10 MHz pass-by panel-type EAS consisting of two overlapping current-carrying coils. Two different relative positions between the EAS and the body (frontal and lateral exposures), which imply the exposure of different parts of the body at different distances, have been considered. In all cases, induced current densities in tissues of the central nervous system and specific absorption rates (SARs) are calculated to be compared with the limits from the guidelines. Results show that induced current densities are lower in the case of adult models as compared with those of children in both lateral and frontal exposures. Maximum SAR values calculated in lateral exposure are significantly lower than those calculated in frontal exposure, where the EAS-body distance is shorter. Nevertheless, in all studied cases, with an EAS driving current of 4 A rms, maximum induced current and SAR values are below basic restrictions.

  4. Particle acceleration through the resonance of high magnetic field and high frequency electromagnetic wave

    E-print Network

    Paris-Sud XI, Universit de

    electromagnetic wave Hong Liu1,4 , X. T. He2,3 , S. G. Chen2 and W.Y.Zhang2 Graduate School, China Academy a few electromagnetic wave cycles through the mechanism which is named electromagnetic and magnetic on the electromagnetic wave intensity, but also on the ratio between electron Larmor frequency and electromagnetic wave

  5. Muon Cooling via Ionization Andrea Kay Forget

    E-print Network

    Cinabro, David

    1 Muon Cooling via Ionization Andrea Kay Forget Department of Physics, Wayne State University decay, as a result of their short lives many of the known cooling techniques (electron, stochastic, and laser cooling) cannot be used to properly cool muons that are being used in proposed accelerators

  6. Sorption cooling: a valid extension to passive cooling

    NASA Astrophysics Data System (ADS)

    Doornink, Jan; Burger, Johannes; ter Brake, Marcel

    2007-10-01

    Passive cooling has shown to be a very dependable cryogenic cooling method for space missions. Several missions employ passive radiators to cool down their delicate sensor systems for many years, without consuming power, without exporting vibrations or producing electromagnetic interference. So for a number of applications, passive cooling is a good choice. At lower temperatures, the passive coolers run into limitations that prohibit accommodation on a spacecraft. The approach to this issue has been to find a technology able to supplement passive cooling for lower temperatures, which maintains as much as possible of the advantages of passive coolers. Sorption cooling employs a closed cycle Joule-Thomson expansion process to achieve the cooling effect. Sorption cells perform the compression phase in this cycle. At a low temperature and pressure, these cells adsorb the working fluid. At a higher temperature they desorb the fluid and thus produce a high-pressure flow to the restriction in the cold stage. The sorption process selected for this application is of the physical type, which is completely reversible. It does not suffer from degradation as is the case with chemical sorption of e.g. hydrogen in metal hydrides. Sorption coolers include no moving parts except for some check valves, they export neither mechanical vibrations nor electromagnetic interference, and are potentially very dependable due to their simplicity. The required cooling temperature determines the type of working fluid to be applied. Sorption coolers can be used in conjunction with passive cooling for heat rejection at different levels. This paper starts with a brief discussion on applications of passive coolers in different types of orbits and the limitations on passive cooling at low cooling temperatures. Next, the working principle of sorption cooling is summarized. The DARWIN mission is chosen as an example application of sorption and passive cooling and special attention is paid to the reduction of the radiator area needed by the sorption cooler. By examining the performance of alternative working fluids suitable for different cooling temperatures, the application field of this type of sorption cooling is currently expanded.

  7. Sorption cooling: A valid extension to passive cooling

    NASA Astrophysics Data System (ADS)

    Doornink, D. J.; Burger, J. F.; ter Brake, H. J. M.

    2008-05-01

    Passive cooling has shown to be a very dependable cryogenic cooling method for space missions. Several missions employ passive radiators to cool down their delicate sensor systems for many years, without consuming power, without exporting vibrations or producing electromagnetic interference. So for a number of applications, passive cooling is a good choice. At lower temperatures, the passive coolers run into limitations that prohibit accommodation on a spacecraft. The approach to this issue has been to find a technology able to supplement passive cooling for lower temperatures, which maintains as much as possible of the advantages of passive coolers. Sorption cooling employs a closed cycle Joule-Thomson expansion process to achieve the cooling effect. Sorption cells perform the compression phase in this cycle. At a low temperature and pressure, these cells adsorb the working fluid. At a higher temperature they desorb the fluid and thus produce a high-pressure flow to the expander in the cold stage. The sorption process selected for this application is of the physical type, which is completely reversible. It does not suffer from degradation as is the case with chemical sorption of, e.g., hydrogen in metal hydrides. Sorption coolers include no moving parts except for some check valves, they export neither mechanical vibrations nor electromagnetic interference, and are potentially very dependable due to their simplicity. The required cooling temperature determines the type of working fluid to be applied. Sorption coolers can be used in conjunction with passive cooling for heat rejection at different levels. This paper starts with a brief discussion on applications of passive coolers in different types of orbits and on the limitations of passive cooling for lower cooling temperatures. Next, the working principle of sorption cooling is summarized. The DARWIN mission is chosen as an example application of sorption and passive cooling and special attention is paid to the reduction of the radiator area needed by the sorption cooler. The application field of this type of sorption cooling in space missions is currently being expanded by examining the performance of alternative working fluids, suitable for different cooling temperatures.

  8. Cavity Cooling with a Hot Cavity Vladan Vuletic

    E-print Network

    Vuletic, Vladan

    of the Doppler effect. Conventional Doppler cooling therefore requires a closed two-level system. Alternatively extended electromagnetic modes. Conventional Doppler cooling [5], that makes use of the conservation, realize an atomic laser, or maybe build time machines? Doppler cooling relies on the anisotropic

  9. 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.

  10. 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.

  11. Electromagnetic interactions at RHIC and LHC

    E-print Network

    M. C. Guclu

    2008-11-15

    At LHC energies the Lorentz factor will be 3400 for the Pb + Pb collisions and the electromagnetic interactions will play important roles. Cross sections for the electromagnetic particle productions are very large and can not be ignored for the lifetimes of the beams and background. In this article, we are going to study some of the electromagnetic processes at RHIC and LHC and show the cross section calculations of the electron-positron pair production with the giant dipole resonance of the ions.

  12. Superfast Cooling

    E-print Network

    S. Machnes; M. B. Plenio; B. Reznik; A. M. Steane; A. Retzker

    2010-01-15

    Currently laser cooling schemes are fundamentally based on the weak coupling regime. This requirement sets the trap frequency as an upper bound to the cooling rate. In this work we present a numerical study that shows the feasibility of cooling in the strong coupling regime which then allows cooling rates that are faster than the trap frequency with state of the art experimental parameters. The scheme we present can work for trapped atoms or ions as well as mechanical oscillators. It can also cool medium size ions chains close to the ground state.

  13. Electromagnetic compatibility

    Microsoft Academic Search

    C. Furse

    2004-01-01

    The focus of this issue's column is teaching electromagnetic compatibility. A summary of resources for this topic is found in the article by Levent Sevgi, and additional online course materials are summarized on the IEEE AP-S education course material repository Web site: www.ece.utah.edu\\/?cfurse\\/APS\\/course.htm. The column also provides a set of suggestions that are applicable to a variety of courses on

  14. 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.

  15. Electromagnetic Spectrum

    NSDL National Science Digital Library

    Part of the larger Imagine the Universe educational site, the Electromagnetic Spectrum site is another great resource from NASA. The site gives clear and easy-to-understand explanations, while providing keywords throughout the page that are linked to a dictionary of terms for easy access to further information. Students will enjoy the colorful illustrations accompanying the text, which vertically follow the spectrum from radio to gamma rays, while teachers will appreciate the related lesson plans link that will help reinforce the learning.

  16. Fundamentals of a floating loop concept based on R134a refrigerant cooling of high heat flux electronics

    Microsoft Academic Search

    C. W. Ayers; J. S. Hsu; K. T. Lowe

    2006-01-01

    The Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) has been developing technologies to address the thermal concerns associated with hybrid electric vehicles (HEVs). This work is part of the ongoing FreedomCAR and Vehicle Technologies program (FCVT), performed for the Department of Energy (DOE). Removal of the heat generated from electrical losses in traction motors

  17. Higher Electronic Excited States of Jet-Cooled Aromatic Hydrocarbon Radicals: 1-PHENYLPROPARGYL, 1-NAPHTHYLMETHYL, 2-NAPHTHYLMETHYL and 9-ANTHRACENYLMETHYL

    NASA Astrophysics Data System (ADS)

    O'Connor, Gerard; Woodhouse, Gabrielle Victoria Grace; Troy, Tyler; Nauta, Klaas; Schmidt, Timothy

    2014-06-01

    The D_0 ? D_1 transitions of many aromatic resonance stabilised radicals (RSRs) have been observed in the gas-phase in recent years. This work has been primarily motivated by the suggestion that such molecules may be carriers of the diffuse interstellar bands (DIBs). Most gas- phase studies of these molecules have focused on the D_0 ? D_1 electronic transitions, primarily due to experimental limitations. These transitions are generally weak, a feature of odd- alternate hydrocarbon radicals, with intensity instead going to an electronically similar higher energy transition. This presentation will focus on higher electronic transitions with calculated intensity f>10-2. Experimental data will be presented for observed strong transitions of three benzilic polycyclic aromatic hydrocarbons (PAHs) radicals' 1-naphthylmethyl, 2-naphthylmethyl and 9-anthracenylmethyl. Experimental data will also be presented of a strong state of the aromatic/aliphatic RSR 1-phenylpropargyl. Trends in this experimental and theoretical data will be used to predict the spectroscopic properties of larger RSR molecules, and the relevance of these higher electronic states to astronomical observations will be discusses.

  18. A survey of mode-conversion transparency windows between external electromagnetic waves and electron Bernstein waves for various plasma slab boundaries

    NASA Astrophysics Data System (ADS)

    Igami, H.; Tanaka, H.; Maekawa, T.

    2006-05-01

    For the plasma slab boundary with monotonically increasing density profile along the x axis and the magnetic field along the z axis, both Nz and Ny components of the refractive index are parallel to the plasma slab and are conserved in the mode-conversion process between the vacuum transverse electromagnetic (TEM) waves and the electron Bernstein (B) waves. Information of Nz and Ny is sufficient to identify the waves uniquely both for TEM waves and B waves coupled by mode conversion. Furthermore, the wave differential equation which governs the mode-conversion process can be written in the normalized form with a few numbers of the normalized parameters and variables for the linear density profile. Thus, the mode-conversion transparency window, which is presented as a contour plot of the mode-conversion rate versus the Nz-Ny plane, can be categorized for the pair of parameters of the density scale length normalized to the wavelength in vacuum Ln/?0 and the frequency to the cyclotron frequency ?/?. A survey of the transparency windows for various parameter ranges of Ln/?0 and ?/? is presented. The windows are categorized into four types. The frosted type at the steepest density gradient region has a broad transparency profile but even the peak is not completely transparent. The perpendicular-X type at the next steep density gradient region also has a broad transparency profile with a completely transparent peak by the perpendicularly propagating extraordinary waves. The OXB type at the gentle density gradient region has a pair of completely transparent sharp peaks by the obliquely propagating ordinary waves at the optimal propagation angles with Nz = Nparopt and Ny = 0. The fourth is the g1 type in the intermediate density gradient region between the above two cases, which has two completely transparent peaks in the window. Finally, a simulation to examine the applicability of the survey to experiments is made using a test density profile, which elucidates key points for the application of the survey.

  19. Reliability of pressure-sensitive adhesive tapes for heat sink attachment in air-cooled electronic assemblies

    Microsoft Academic Search

    Valrie Eveloy; Peter Rodgers; Michael G. Pecht

    2004-01-01

    This study investigates the reliability of commercially available pressure-sensitive adhesive (PSA) tapes used for electronic component-to-heat sink attachment. It is found that creep can affect the PSA reliability. Therefore, creep is experimentally characterized using isothermal, constant load, double lap shear measurements in conditions representative of vertically oriented heat sink applications. PSA joint life predictions are derived from the accelerated creep

  20. Bremsstrahlung in the scattering of low-energy electrons by neutral atomic systems. [in atmosphere of sun and cool stars

    NASA Technical Reports Server (NTRS)

    Gould, R. J.

    1985-01-01

    By elementary methods, the cross section for electron-atom and electron-molecule bremsstrahlung is computed in the limit when the incident electron energy is much less than Ry. The procedure employs the classical soft-photon emission probability formula for general (h/2pi)(omega), yielding a simple expression for the bremsstrahlung cross section in terms of the total elastic scattering cross section. The validity of the method is discussed, and results are compared with more elaborate and accurate calculations. Comparison is made with ('free-free') opacity calculations for the associated process at the temperature (6300 K) of the solar atmosphere. For chi sub omega = (h/2pi)(omega)/kT = 1, the computed absorption coefficient is within 2, 7, and 12 percent of accurate calculations for scatterings by H, He, and H2, respectively. The general dependence of the opacity on chi sub omega is described well by the simple formula, although the error is larger for higher chi sub omega; it is suggested that the inaccuracy at high frequencies is due to the failure of the soft-photon approximation.

  1. 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.

  2. Superconducting electromagnetic thruster

    SciTech Connect

    Meng, J.

    1993-02-11

    An electromagnetic thruster for marine vehicles using a jet of water driven by the interaction of a mutually perpendicular intensified magnetic field and an intensified electric field is disclosed. The intensified magnetic field is produced by superconducting coils cooled by a coolant such as liquid helium. An intensified electric field is produced by passing high amperage current across the seawater jet. These interacting fields produce a Lorentz force perpendicular to mutually perpendicular electric and magnetic field vectors which is used to drive the seawater jet. In some embodiments, the force may also be used to draw water into the jet from the boundary layer flow around the vehicle thereby reducing boundary layer turbulence and associated radiated noise.

  3. 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.

  4. 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.

  5. Transient electromagnetic interference in substations

    Microsoft Academic Search

    C. M. Wiggins; D. E. Thomas; F. S. Nickel; T. M. Salas; S. E. Wright

    1994-01-01

    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

  6. Electromagnetic microactuators

    NASA Astrophysics Data System (ADS)

    Bttgenbach, 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.

  7. Standing Electromagnetic Solitons in Degenerate Relativistic Plasmas

    E-print Network

    Mikaberidze, G

    2015-01-01

    The existence of standing high frequency electromagnetic (EM) solitons in a fully degenerate overdense electron plasma is studied applying relativistic hydrodynamics and Maxwell equations. The stable soliton solutions are found in both relativistic and nonrelativistic degenerate plasmas.

  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 (2001100?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. Cooling a quantum circuit via coupling to a multiqubit system

    E-print Network

    Mihai A. Macovei

    2010-04-19

    The cooling effects of a quantum LC circuit coupled inductively with an ensemble of artificial qubits are investigated. The particles may decay independently or collectively through their interaction with the environmental vacuum electromagnetic field reservoir. For appropriate bath temperatures and the resonator's quality factors, we demonstrate an effective cooling well below the thermal background. In particular, we found that for larger samples the cooling efficiency is better for independent qubits. However, the cooling process can be faster for collectively interacting particles.

  10. 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

  11. 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.

  12. 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. [Princeton Plasma Physics Laboratory, Princeton New Jersey 08543 (United States); Candy, J. [General Atomics, San Diego, California 92186 (United States); Nevins, W. M.; Wang, E. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Yuh, H. [Nova Photonics Inc., Princeton, New Jersey 08540 (United States)

    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.

  13. 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.

  14. 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)

  15. The S1(1A1)-S0(1A1) Electronic Transition of Jet-Cooled o-Difluorobenzene.

    PubMed

    Swinn; Kable

    1998-09-01

    A detailed study of the S1(1A1)-S0(1A1) transition of jet-cooled o-difluorobenzene has been completed using the two techniques of laser-induced fluorescence excitation and dispersed, single vibronic level fluorescence spectroscopy. Analysis of over 60 dispersed fluorescence spectra resulted in both the assignment of 22 excited state vibrational frequencies and the confirmation of 23 ground state frequencies. The spectrum is dominated by Franck-Condon activity in totally symmetric vibrations with long progressions in the ring-breathing mode, nu9. By analogy with benzene and the para- and meta-substituted isomers, two vibronic coupling mechanisms are postulated to be responsible for the wealth of weaker symmetry-forbidden structure that has been observed. Single quantum changes in b2 vibrations are postulated to appear due to first order vibronic coupling to a higher lying B2 electronic state. Combinations of b1 and a2 modes are postulated to appear from second order vibronic coupling to an A1 electronic state. This second order coupling causes a pronounced Duschinsky mixing among excited state b1 and a2 modes with respect to their ground state counterparts. Franck-Condon factors are calculated for the a1 progression-forming modes, anharmonic contributions are evaluated, one strong Fermi resonance is identified and analyzed, and the Duschinsky rotation matrix elements are evaluated for the most strongly affected modes, nu17 and nu18. Several transitions in the oDFB-oDFB van der Waals dimer and oDFB-Ar complex are also assigned in the spectrum. Copyright 1998 Academic Press. PMID:9724580

  16. Cooled railplug

    DOEpatents

    Weldon, William F. (Austin, TX)

    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.

  17. L- and U-shaped heat pipes thermal modules with twin fans for cooling of electronic system under variable heat source areas

    NASA Astrophysics Data System (ADS)

    Wang, Jung-Chang

    2014-04-01

    This study utilizes a versatile superposition method with thermal resistance network analysis to design and experiment on a thermal module with embedded six L-shaped or two U-shaped heat pipes and plate fins under different fan speeds and heat source areas. This type of heat pipes-heat sink module successively transfer heat capacity from a heat source to the heat pipes, the heat sink and their surroundings, and are suitable for cooling electronic systems via forced convection mechanism. The thermal resistances contain all major components from the thermal interface through the heat pipes and fins. Thermal performance testing shows that the lowest thermal resistances of the representative L- and U-shaped heat pipes-heat sink thermal modules are respectively 0.25 and 0.17 C/W under twin fans of 3,000 RPM and 30 30 mm2 heat sources. The result of this work is a useful thermal management method to facilitate rapid analysis.

  18. Electromagnetic topology: Characterization of internal electromagnetic coupling

    NASA Technical Reports Server (NTRS)

    Parmantier, J. P.; Aparicio, J. P.; Faure, F.

    1991-01-01

    The main principles are presented of a method dealing with the resolution of electromagnetic internal problems: Electromagnetic Topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of the Electromagnetic Topology: the BLT equation. This generalization is illustrated by the treatment of an aperture as a four port junction. Analytical and experimental derivations of the scattering parameters are presented. These concepts are used to study the electromagnetic coupling in a scale model of an aircraft, and can be seen as a convenient means to test internal electromagnetic interference.

  19. 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.

  20. Cool School.

    ERIC Educational Resources Information Center

    Stephens, Suzanne

    1980-01-01

    The design for Floyd Elementary School in Miami (Florida) seeks to harness solar energy to provide at least 70 percent of the annual energy for cooling needs and 90 percent for hot water. (Author/MLF)

  1. Ventilative cooling

    E-print Network

    Graa, Guilherme Carrilho da, 1972-

    1999-01-01

    This thesis evaluates the performance of daytime and nighttime passive ventilation cooling strategies for Beijing, Shanghai and Tokyo. A new simulation method for cross-ventilated wind driven airflow is presented . This ...

  2. Cool Vest

    NASA Technical Reports Server (NTRS)

    1982-01-01

    ILC, Dover Division's lightweight cooling garment, called Cool Vest was designed to eliminate the harmful effects of heat stress; increases tolerance time in hot environments by almost 300 percent. Made of urethane-coated nylon used in Apollo, it works to keep the body cool, circulating chilled water throughout the lining by means of a small battery-powered pump. A pocket houses the pump, battery and the coolant which can be ice or a frozen gel, a valve control allows temperature regulation. One version is self-contained and portable for unrestrained movement, another has an umbilical line attached to an external source of coolant, such as standard tap water, when extended mobility is not required. It is reported from customers that the Cool Vest pays for itself in increased productivity in very high temperatures.

  3. New fine structure cooling rate

    NASA Technical Reports Server (NTRS)

    Hoegy, W. R.

    1976-01-01

    One of the dominant electron cooling processes in the ionosphere is caused by electron impact induced fine structure transitions among the ground state levels of atomic oxygen. This fine structure cooling rate is based on theoretical cross sections. Recent advances in the numerical cross section determinations to include polarization effects and more accurate representations of the atomic target result in new lower values. These cross sections are employed in this paper to derive a new fine structure cooling rate which is between 40% and 60% of the currently used rate. A new generalized formula is presented for the cooling rate (from which the fine structure cooling rate is derived), valid for arbitrary mass and temperature difference of the colliding particles and arbitrary inelastic energy difference.

  4. 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.

  5. Narrow field electromagnetic sensor system and method

    DOEpatents

    McEwan, Thomas E. (Livermore, CA)

    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.

  6. Biological effects of electromagnetic fields.

    PubMed

    Macr, M. A.; Di Luzio, Sr.; Di Luzio, S.

    2002-01-01

    Nowadays, concerns about hazards from electromagnetic fields represent an alarming source for human lives in technologically developed countries. We are surrounded by electromagnetic fields everywhere we spend our working hours, rest or recreational activities. The aim of this review is to summarize the biological effects due to these fields arising from power and transmission lines, electrical cable splices, electronic devices inside our homes and work-places, distribution networks and associated devices such as cellular telephones and wireless communication tower, etc. Special care has been reserved to study the biological effects of electromagnetic fields on cell lines of the mammalian immune system about which our research group has been working for several years. PMID:12590871

  7. Electromagnetic Field Theory

    E-print Network

    Hart, Gus

    Electromagnetic Field Theory BO THID? UPSILON BOOKS #12;#12;ELECTROMAGNETIC FIELD THEORY #12;#12;Electromagnetic Field Theory BO THID? Swedish Institute of Space Physics and Department of Astronomy and Space, Sweden UPSILON BOOKS · COMMUNA AB · UPPSALA · SWEDEN #12;Also available ELECTROMAGNETIC FIELD THEORY

  8. Electromagnetic wave test

    Microsoft Academic Search

    R. K. Matthews; S. A. Stepanek

    1993-01-01

    Electromagnetic wave testing, which represents a relatively new test technique that involves the union of several disciplines (aerothermodynamics, electromagnetics, materials\\/structures, and advanced diagnostics) is introduced. The essence of this new technique deals with the transmission and possible distortion of electromagnetic waves (RF or IR) as they pass through the bow shock, flow field, and electromagnetic window of a missile flying

  9. Laser cooling of solids

    NASA Astrophysics Data System (ADS)

    Nemova, Galina; Kashyap, Raman

    2010-08-01

    Laser cooling of solids, sometimes also known as optical refrigeration, is a fast developing area of optical science, investigating the interaction of light with condensed matter. Apart from being of fundamental scientific interest, this topic addresses a very important practical issue: design and construction of laser pumped solid-state cryocoolers, which are compact, free from mechanical vibrations, moving parts, fluids and can cause only low electromagnetic interference in the cooled area. The optical cryocooler has a broad area of applications such as in the development of magnetometers for geophysical sensors, in biomedical sensing and can be beneficial for satellite instrumentations and small sensors, where compactness and the lack of vibrations are very important. Simply, a laser cooler works on the conversion of low energy pump photons into high-energy anti-Stokes fluorescence photons by extracting some of the phonons (heat energy) in a material. That is, the process of laser cooling of solids is based on anti-Stokes fluorescence also known as luminescence upconversion, when light quanta in the red tail of the absorption spectrum are absorbed from a pump laser, and blue-shifted photons are spontaneously emitted. The extra energy extracted from the solid-state lattice in the form of the phonons is the quanta of vibrational energy which generates heat. The idea to cool solids with anti-Stokes fluorescence was proposed in 1929 by Peter Pringsheim and first demonstrated experimentally by Epstein's research team in 1995. In 1999, Steven Bowman proposed to use the optical refrigeration by anti-Stokes fluorescence within the laser medium to balance the heat generated by the Stokes shifted stimulated emission in a high-power solid-state bulk laser. Such a laser without internal heating named radiation-balanced or athermal laser was experimentally demonstrated for the first time in 2002. At the present time laser cooling of solids can be largely divided into three main areas: laser cooling of rare-earth doped solids, laser cooling in semiconductors and radiation-balanced lasers. All three areas are very interesting and important and will be considered in this paper.

  10. Electromagnetic launchers

    NASA Astrophysics Data System (ADS)

    Kolm, H.; Mongeau, P.; Williams, F.

    1980-09-01

    Recent advances in energy storage, switching and magnet technology make electromagnetic acceleration a viable alternative to chemical propulsion for certain tasks, and a means to perform other tasks not previously feasible. Applications include the acceleration of gram-size particles for hypervelocity research and the initiation of fusion by impact, a replacement for chemically propelled artillery, the transportation of cargo and personnel over inaccessible terrain, and the launching of space vehicles to supply massive space operations, and for the disposal of nuclear waste. The simplest launcher of interest is the railgun, in which a short-circuit slide or an arc is driven along two rails by direct current. The most sophisticated studied thus far is the mass driver, in which a superconducting shuttle bucket is accelerated by a line of pulse coils energized by capacitors at energy conversion efficiencies better than 90%. Other accelerators of interest include helical, brush-commutated motors, discrete coil arc commutated drivers, flux compression momentum transformers, and various hybrid electrochemical devices.

  11. 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 temper

  12. Advance in MEIC cooling studies

    SciTech Connect

    Zhang, Yuhong [JLAB, Newport News, VA (United States); Derbenev, Ya. [JLAB, Newport News, VA (United States); Douglas, D. [JLAB, Newport News, VA (United States); Hutton, A. [JLAB, Newport News, VA (United States); Kimber, A. [JLAB, Newport News, VA (United States); Li, R. [JLAB, Newport News, VA (United States); Nissen, E. [JLAB, Newport News, VA (United States); Tennant, [JLAB, Newport News, VA (United States); Zhang, H. [JLAB, Newport News, VA (United States)

    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.

  13. Sharing the protection of aircraft electronic systems against the effects of high-level electromagnetic environments between traditional protection and system architecture

    NASA Astrophysics Data System (ADS)

    Hess, Richard F.; Yount, Larry J.; Knoller, Henry; Masson, Gerald M.; Larsen, William E.

    It is shown how architectural techniques can be used as a complement to traditional protection techniques to provide additional protection of sensitive avionics against high-level electromagnetic fields. Consideration is given to potential threats, the data processor susceptibility response, protection from the threat, system architecture, and transparent recovery. The wave shape of engineering waveforms that reproduce important lightning waveform parameters (amplitude, rise time, and action integral) is presented.

  14. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: On the feasibility of raising the density and the extension of atomic ensembles in laser cooling

    NASA Astrophysics Data System (ADS)

    Rivlin, Lev A.; Yakubovich, S. D.

    2000-11-01

    The ways of raising the limiting density of cooled atoms and the extension of the volume occupied by them are considered. These include raising the laser beam intensity above the saturation intensity of the working transition, the use of a noncollinear geometry of the laser beam and the atomic medium, and coherent cooling by sequences of counterpropagating ?-pulses.

  15. Transresonant Electron Acceleration

    Microsoft Academic Search

    E. N. Parker; Enrico Fermi

    1961-01-01

    ttelliwell and Bell have suggested synchronous acceleration of electrons by electromagnetic waves in the whistler range in the geomagnetic field. The acceleration of trapped electrons by electromagnetic waves is here generalized to include nonsynchronous or transresonant acceleration. It is shown that whistlers will scatter the electron velocity, by an amount inversely proportional to the square root of the time rate

  16. Free-electron lasers

    Microsoft Academic Search

    Luis R. Elias

    1993-01-01

    In a free-electron laser an electron beam interacts with a periodic electromagnetic structure to amplify electromagnetic waves. A short history of the device, a summary of major accomplishments, and a tutorial single particle free-electron laser physics analysis are presented.

  17. The electronic spectrum, molecular structure, and oscillatory fluorescence decay of jet-cooled germylidene (H2C=74Ge), the simplest unsaturated germylene

    NASA Astrophysics Data System (ADS)

    Hostutler, David A.; Smith, Tony C.; Li, Haiyang; Clouthier, Dennis J.

    1999-07-01

    The electronic spectrum of germylidene (H2C=Ge), the simplest unsaturated germylene, has been observed for the first time. Jet-cooled H2CGe and D2CGe were produced by an electric discharge through tetramethylgermane diluted in argon at the exit of a supersonic expansion. High-resolution spectra of H2C74Ge and D2C74Ge, obtained from (CH3)474Ge prepared from isotopically enriched 74Ge metal, have been rotationally analyzed to yield the following r0 structures: r0?(CGe)=1.7908(2) , r0?(CH)=1.1022(5) , ?0?(HCH)=115.05(5), r0'(CGe)=1.914(4) , r0'(CH)=1.082(9) , and ?0'(HCH)=139.3(11). The 367-354 nm B1B2-X 1A1 band system consists of prominent perpendicular bands involving the CGe stretching (?3) and CH2 scissors (?2) vibrations and a weaker series of vibronically induced parallel bands involving the CH2 rocking mode (?6). Vibronic bands involving ?v=2 changes in ?6(b2) and ?4(b1) have also been assigned. The fluorescence decays of single rotational levels of the 000 band of H2C74Ge exhibit molecular quantum beats for about 70% of the levels surveyed. Density of states arguments reveal that most of the beats originate from interactions with high rovibronic levels of the ground state. In one case, hyperfine splittings in the Fourier transform of the beat pattern indicate an accidental coincidence with an excited triplet state level. The less frequent occurrence of quantum beats in germylidene compared to silylidene, where they are almost universal, can be attributed to the smaller density of ground state levels at the zero-point energy of the S2 state in the former.

  18. 7. Electromagnetic relations 1 7. ELECTROMAGNETIC RELATIONS

    E-print Network

    7. Electromagnetic relations 1 7. ELECTROMAGNETIC RELATIONS Revised September 2005 by H.G. Spieler = 10-7 N A-2 ; c = 1 0 0 = 2.997 924 58 ? 108 m s-1 #12;2 7. Electromagnetic relations 7.1. Impedances of self-inductance L: Z = jL . Impedance of capacitance C: Z = 1/jC . Impedance of free space: Z = 0/ 0

  19. 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.

  20. Laser cooling of magnesium ions: Preliminary experimental results

    Microsoft Academic Search

    F. Plumelle; M. Desaintfuscien; M. Jardino; P. Petit

    1986-01-01

    We describe a laser-cooling experiment on Mg+ ions confined in an electromagnetic trap (Penning trap or rf trap) and give the preliminary experimental results. In particular, we have observed a laser cooling in the Penning trap configuration in which a measured temperature of about 1 K has been obtained.

  1. A Cubical Chamber and LaBVIEW Program To Study Time Dependence of Temperature, Electron and X-Ray Yield and Target Current for Heated and Cooled Pyroelectric Crystals in Dilute Gas

    NASA Astrophysics Data System (ADS)

    Shafroth, Stephen; Bedair, Sarah; Karwowski, Hugon; Brownridge, James

    2002-05-01

    One of us (JDB)^1 found that pyroelectric crystals such as LiNbO-3 attract energetic electrons to the - z base on heating while they repel electrons on cooling. This gives rise to Nb K X-Rays and brehmstrahlung on heating and target eg. Cu K X-Rays on cooling. Here we present data obtained with a LabVIEW program by SB which controls the crystal temperature and records the X-ray and electron emission rates as well as target current and pressure under different thermal and pressure conditions. The experimental arrangement consists of a 4 inch Al cube with 6 dependix compatible ports, one of which was a mylar X-ray window. The - z base of the crystal was located sim 20 mm below the center of the cube and was viewed directly by an x-ray detector (a survey meter). Current incident on an insulated target rod was recorded vs time and temperature. A Cu target with a pin- hole in the center was oriented at 45^0 and an 100 ? surface barrier electron detector was located above the crystal so that x-rays and electrons could be detected at the same time. 1. J. D. Brownridge, Nature (London) 358, 278 (1992).

  2. CONTINUUM ELECTROMAGNETIC RADIATION FROM SOLAR FLARES

    Microsoft Academic Search

    W. A. Stein; E. P. Ney

    1963-01-01

    Continuum electromagnetic radiation from solar flares is discussed in ; terms of the energy loss processes of electrons in the solar atmosphere. It is ; shown that it is possible to attribute the continuum radiation both at radio ; frequencies and at visible frequencies to synchrotron radiation by exponential ; rigidity distributions of electrons. (auth);

  3. 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.

  4. Development of the strong electromagnet wiggler

    SciTech Connect

    Burns, M.J.; Deis, G.A.; Holmes, R.H.; Van Maren, R.D.; Halbach, K.

    1988-03-01

    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 th4e wiggler field and operate at low current densities by virtue of their placement away from the midplane. The authors describe the design approach used and test data from a 7-period wiggler prototype that includes curved pole tips to provide wiggler-plane focusing.

  5. ELECTROMAGNETIC MODELING AND OPTIMIZATION USING NEURAL NETWORKS

    Microsoft Academic Search

    Q. J. Zhang

    2008-01-01

    Electromagnetic modelling and optimization is important for designing high- frequency electronic circuits used in computers and wireless communications. Wireless technologies at higher frequency bands from radio- frequency (RF) to microwave and millimeter-waves are being explored. The push for bandwidth in wireline communication drives the signal speed to m ulti- gigabits per second and beyond. At such high- frequency\\/high-speed, the electromagnetic

  6. Electromagnetic Calorimeter for HADES

    E-print Network

    W. Czyzycki; E. Epple; L. Fabbietti; M. Golubeva; F. Guber; A. Ivashkin; M. Kajetanowicz; A. Krasa; F. Krizek; A. Kugler; K. Lapidus; E. Lisowski; J. Pietraszko; A. Reshetin; P. Salabura; Y. Sobolev; J. Stanislav; P. Tlusty; T. Torrieri; M. Traxler

    2011-11-28

    We propose to build the Electromagnetic calorimeter for the HADES di-lepton spectrometer. It will enable to measure the data on neutral meson production from nucleus-nucleus collisions, which are essential for interpretation of dilepton data, but are unknown in the energy range of planned experiments (2-10 GeV per nucleon). The calorimeter will improve the electron-hadron separation, and will be used for detection of photons from strange resonances in elementary and HI reactions. Detailed description of the detector layout, the support structure, the electronic readout and its performance studied via Monte Carlo simulations and series of dedicated test experiments is presented. The device will cover the total area of about 8 m^2 at polar angles between 12 and 45 degrees with almost full azimuthal coverage. The photon and electron energy resolution achieved in test experiments amounts to 5-6%/sqrt(E[GeV]) which is sufficient for the eta meson reconstruction with S/B ratio of 0.4% in Ni+Ni collisions at 8 AGeV. A purity of the identified leptons after the hadron rejection, resulting from simulations based on the test measurements, is better than 80% at momenta above 500 MeV/c, where time-of-flight cannot be used.

  7. Quantum states and linear response in dc and electromagnetic fields for charge current and spin polarization of electrons at Bi/Si interface with giant spin-orbit coupling

    E-print Network

    Khomitsky, D V

    2011-01-01

    An expansion of the nearly free-electron model constructed by Frantzeskakis, Pons and Grioni [Phys. Rev. B {\\bf 82}, 085440 (2010)] describing quantum states at Bi/Si(111) interface with giant spin-orbit coupling is developed and applied for the band structure and spin polarization calculation, as well as for the linear response analysis for charge current and induced spin caused by dc field and by electromagnetic radiation. It is found that the large spin-orbit coupling in this system may allow resolving the spin-dependent properties even at room temperature and at realistic collision rate. The geometry of the atomic lattice combined with spin-orbit coupling leads to an anisotropic response both for current and spin components related to the orientation of the external field. The in-plane dc electric field produces only the in-plane components of spin in the sample while both the in-plane and out-of-plane spin components can be excited by normally propagating electromagnetic wave with different polarizations...

  8. Quantum states and linear response in dc and electromagnetic fields for charge current and spin polarization of electrons at Bi/Si interface with giant spin-orbit coupling

    E-print Network

    D. V. Khomitsky

    2011-05-21

    An expansion of the nearly free-electron model constructed by Frantzeskakis, Pons and Grioni [Phys. Rev. B {\\bf 82}, 085440 (2010)] describing quantum states at Bi/Si(111) interface with giant spin-orbit coupling is developed and applied for the band structure and spin polarization calculation, as well as for the linear response analysis for charge current and induced spin caused by dc field and by electromagnetic radiation. It is found that the large spin-orbit coupling in this system may allow resolving the spin-dependent properties even at room temperature and at realistic collision rate. The geometry of the atomic lattice combined with spin-orbit coupling leads to an anisotropic response both for current and spin components related to the orientation of the external field. The in-plane dc electric field produces only the in-plane components of spin in the sample while both the in-plane and out-of-plane spin components can be excited by normally propagating electromagnetic wave with different polarizations.

  9. Quantum states and linear response in dc and electromagnetic fields for the charge current and spin polarization of electrons at the Bi/Si interface with the giant spin-orbit coupling

    SciTech Connect

    Khomitsky, D. V., E-mail: khomitsky@phys.unn.ru [Lobachevskii State University of Nizhni Novgorod (Russian Federation)

    2012-05-15

    An expansion of the nearly free-electron model constructed by Frantzeskakis, Pons, and Grioni [1] describing quantum states at the Bi/Si(111) interface with the giant spin-orbit coupling is developed and applied for the band structure and spin polarization calculation, as well as for the linear response analysis of the charge current and induced spin caused by a dc field and by electromagnetic radiation. It is found that the large spin-orbit coupling in this system may allow resolving the spin-dependent properties even at room temperature and at a realistic collision rate. The geometry of the atomic lattice combined with spin-orbit coupling leads to an anisotropic response for both the current and spin components related to the orientation of the external field. The in-plane dc electric field produces only the in-plane components of spin in the sample, while both the in-plane and out-of-plane spin components can be excited by normally propagating electromagnetic wave with different polarizations.

  10. Quantum states and linear response in dc and electromagnetic fields for the charge current and spin polarization of electrons at the Bi/Si interface with the giant spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Khomitsky, D. V.

    2012-05-01

    An expansion of the nearly free-electron model constructed by Frantzeskakis, Pons, and Grioni [1] describing quantum states at the Bi/Si(111) interface with the giant spin-orbit coupling is developed and applied for the band structure and spin polarization calculation, as well as for the linear response analysis of the charge current and induced spin caused by a dc field and by electromagnetic radiation. It is found that the large spin-orbit coupling in this system may allow resolving the spin-dependent properties even at room temperature and at a realistic collision rate. The geometry of the atomic lattice combined with spin-orbit coupling leads to an anisotropic response for both the current and spin components related to the orientation of the external field. The in-plane dc electric field produces only the in-plane components of spin in the sample, while both the in-plane and out-of-plane spin components can be excited by normally propagating electromagnetic wave with different polarizations.

  11. Electromagnetic properties of neutrinos

    E-print Network

    Carlo Giunti; Alexander Studenikin

    2010-06-08

    A short review on electromagnetic properties of neutrinos is presented. In spite of many efforts in the theoretical and experimental studies of neutrino electromagnetic properties, they still remain one of the main puzzles related to neutrinos.

  12. Investigation of electromagnetic welding

    E-print Network

    Pressl, Daniel G. (Daniel Gerd)

    2009-01-01

    We propose several methodologies to study and optimize the electromagnetic process for Electromagnetic Forming (EMF) and Welding (EMW), thereby lowering the necessary process energy up to a factor of three and lengthening ...

  13. Cavity cooling a single charged nanoparticle

    E-print Network

    J. Millen; P. Z. G. Fonseca; T. Mavrogordatos; T. S. Monteiro; P. F. Barker

    2014-11-25

    The development of laser cooling coupled with the ability to trap atoms and ions in electromagnetic fields, has revolutionised atomic and optical physics, leading to the development of atomic clocks, high-resolution spectroscopy and applications in quantum simulation and processing. However, complex systems, such as large molecules and nanoparticles, lack the simple internal resonances required for laser cooling. Here we report on a hybrid scheme that uses the external resonance of an optical cavity, combined with radio frequency (RF) fields, to trap and cool a single charged nanoparticle. An RF Paul trap allows confinement in vacuum, avoiding instabilities that arise from optical fields alone, and crucially actively participates in the cooling process. This system offers great promise for cooling and trapping a wide range of complex charged particles with applications in precision force sensing, mass spectrometry, exploration of quantum mechanics at large mass scales and the possibility of creating large quantum superpositions.

  14. Electromagnetic Interference (Emi)

    Microsoft Academic Search

    Mike Hardage; Philip D. Henry

    \\u000a Electric and magnetic signals originating outside of a defibrillator may affect its operation, a phenomenon known as electromagnetic\\u000a interference (EMI). EMI usually refers to interference from environmental electromagnetic instrumentation and should be distinguished\\u000a from other sources of electromagnetic noise causing ICD malfunction (Table 1). Signals most likely to penetrate and affect\\u000a pacemakers and ICDs are electromagnetic waves or signals at

  15. 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.

  16. Electromagnetic space-time crystals. III. Dispersion relations for partial solutions

    E-print Network

    G. N. Borzdov

    2014-10-21

    Partial solutions of the Dirac equation describing an electron motion in electromagnetic crystals created by plane waves with linear and circular polarizations are treated. It is shown that the electromagnetic crystal formed by circularly polarized waves possesses the spin birefringence.

  17. Electromagnetic effects on transportation systems

    SciTech Connect

    Morris, M.E.; Dinallo, M.A.

    1996-05-01

    Electronic and electrical system protection design can be used to eliminate deleterious effects from lightning, electromagnetic interference, and electrostatic discharges. Evaluation of conventional lightning protection systems using advanced computational modeling in conjunction with rocket-triggered lightning tests suggests that currently used lightning protection system design rules are inadequate and that significant improvements in best practices used for electronic and electrical system protection designs are possible. A case study of lightning induced upset and failure of a railway signal and control system is sketched.

  18. Electromagnetic Measurements at RHIC

    E-print Network

    Hamagaki, Hideki

    Electromagnetic Measurements at RHIC Hideki Hamagaki Center for Nuclear Study Graduate School of Science the University of Tokyo #12;2006/06/29 "Electromagnetic measurements at RHIC"@ATHIC 2006 Hideki;2006/06/29 "Electromagnetic measurements at RHIC"@ATHIC 2006 Hideki Hamagaki 3 Prologue ­ scope of EM measurements · EM

  19. Electromagnetic Measurements at RHIC

    E-print Network

    Hamagaki, Hideki

    Electromagnetic Measurements at RHIC Hideki Hamagaki Center for Nuclear Study University of Tokyo #12;2/10/2005 "Electromagnetic measurements at RHIC"@ICPAQGP 05 Hideki Hamagaki 2 Prologue · EM probe and where they are produced; #12;2/10/2005 "Electromagnetic measurements at RHIC"@ICPAQGP 05 Hideki Hamagaki

  20. The State of the Art in Hadron Beam Cooling

    Microsoft Academic Search

    L. R. Prost; P. Derwent

    2008-01-01

    Cooling of hadron beams (including heavy-ions) is a powerful technique by which accelerator facilities around the world achieve the necessary beam brightness for their physics research. In this paper, we will give an overview of the latest developments in hadron beam cooling, for which high energy electron cooling at Fermilab's Recycler ring and bunched beam stochastic cooling at Brookhaven National

  1. Electromagnetically driven dwarf tornados in turbulent convection

    NASA Astrophysics Data System (ADS)

    Kenjere, Saa

    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<=5109). 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.

  2. Cool It!

    NSDL National Science Digital Library

    WNET

    2009-01-01

    In this fun hands-on activity, learners use simple materials to investigate evaporation. How can the evaporation of water on a hot day be used to cool an object? Find out the experimental way! The activity is based on an episode of Cyberchase called "Digit's B-Day Surprise" and was developed to capture kids' interest in math using the appeal of the popular PBS series.

  3. Cryogenic Heat Pipe for Cooling High Temperature Superconductors with Application to

    E-print Network

    Cryogenic Heat Pipe for Cooling High Temperature Superconductors with Application;#12;Cryogenic Heat Pipe for Cooling High Temperature Superconductors with Application to Electromagnetic at the Massachusetts Institute of Technology. 3 #12;#12;5 Cryogenic Heat Pipe for Cooling High Temperature

  4. Conversion of electromagnetic waves at the ionisation front

    SciTech Connect

    Chegotov, M V [Institute for High Energy Densities, Associated Institute for High Temperatures, Russian Academy of Sciences, Moscow (Russian Federation)

    2001-09-30

    It is shown that a weak electromagnetic pulse interacting with a copropagating ionisation front is converted in the general case into three electromagnetic pulses with higher and lower frequencies, which propagate in different directions. The coefficients of conversion to these pulses (for intensities) were found as functions of the frequency. The electromagnetic energy is shown to decrease during this conversion because of the losses for the residual electron energy. (interaction of laser radiation with matter. laser plasma)

  5. Electric and electromagnetic shielding properties of highly conducting polyaniline films

    Microsoft Academic Search

    Song Yuexian; Hongli' WENG; Zheng Yuansuo

    2002-01-01

    The increasing use of commercial, military, and scientific electrical products and electronic devices has raised the problem of electromagnetic interference (EMI), also called electromagnetic environmental pollution, so there is an increased interest in EMI shielding. By use of mechanical mixing doping method, highly conducting polyaniline (PANI) films were prepared by the variation of dopant (camphor sulphonic acid) loading and solvent

  6. Detailed observations of the source of terrestrial narrowband electromagnetic radiation

    Microsoft Academic Search

    W. S. Kurth

    1982-01-01

    We present detailed observations of a region near the terrestrial plasmapause where narrowband electromagnetic radiation (previously called escaping nonthermal continuum radiation) is being generated. These observations show a direct correspondence between the narrowband radio emissions and electron cyclotron harmonic waves near the upper hybrid resonance frequency. In addition, electromagnetic radiation propagating in the Z-mode is observed in the source region

  7. 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.

  8. 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. [Laboratorio de Fisica Teorica e Computacional (LFTC), Universidade Cruzeiro do Sul, 01506-000, Sao Paulo (Brazil)

    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.

  9. 8.07 Electromagnetism II, Fall 2002

    E-print Network

    Zwiebach, Barton

    Survey of basic electromagnetic phenomena: electrostatics, magnetostatics; electromagnetic properties of matter. Time-dependent electromagnetic fields and Maxwell's equations. Electromagnetic waves, emission, absorption, ...

  10. Exploring the Electromagnetic Spectrum

    NSDL National Science Digital Library

    2014-09-18

    Students learn the basics of the electromagnetic spectrum and how various types of electromagnetic waves are related in terms of wavelength and energy. In addition, they are introduced to the various types of waves that make up the electromagnetic spectrum including, radio waves, ultraviolet waves, visible light and infrared waves. These topics help inform students before they turn to designing solutions to an overarching engineering challenge question.

  11. Perfect electromagnetic conductor

    Microsoft Academic Search

    Ismo V. Lindell; Ari Sihvola

    2005-01-01

    In differential-form representation, the Maxwell equations are represented by simple differential relations between the electromagnetic two-forms and source three-forms while the electromagnetic medium is defined through a constitutive relation between the two-forms. The simplest of such relations expresses the electromagnetic two-forms as scalar multiples of one another. Because of its strange properties, the corresponding medium has been considered as nonphysical.

  12. Drift effects on electromagnetic geodesic acoustic modes

    NASA Astrophysics Data System (ADS)

    Sgalla, R. J. F.

    2015-02-01

    A two fluid model with parallel viscosity is employed to derive the dispersion relation for electromagnetic geodesic acoustic modes (GAMs) in the presence of drift (diamagnetic) effects. Concerning the influence of the electron dynamics on the high frequency GAM, it is shown that the frequency of the electromagnetic GAM is independent of the equilibrium parallel current but, in contrast with purely electrostatic GAMs, significantly depends on the electron temperature gradient. The electromagnetic GAM may explain the discrepancy between the f 40 kHz oscillation observed in tokamak TCABR [Yu. K. Kuznetsov et al., Nucl. Fusion 52, 063044 (2012)] and the former prediction for the electrostatic GAM frequency. The radial wave length associated with this oscillation, estimated presently from this analytical model, is ?r 25 cm, i.e., an order of magnitude higher than the usual value for zonal flows (ZFs).

  13. Peltier cooling of superconducting current leads

    Microsoft Academic Search

    F. K. Gehring; M. E. Httner; R. P. Huebener

    2001-01-01

    An interesting application of Peltier cooling based on the Peltier materials presently available arises for the cooling of current leads connected to superconducting power electronics. By inserting n-doped and p-doped Peltier tablets at the warm end into the circuit, at their warm side the remaining current leads can be Peltier cooled about 5060 K below room temperature. We have developed

  14. Meson electromagnetic form factors

    E-print Network

    Stanislav Dubnicka; Anna Z. Dubnickova

    2012-10-23

    The electromagnetic structure of the pseudoscalar meson nonet is completely described by the sophisticated Unitary&Analytic model, respecting all known theoretical properties of the corresponding form factors.

  15. How Strong are Electromagnets?

    NSDL National Science Digital Library

    This is an activity about electromagnetism. Using a battery and a length of wire, learners will construct an electromagnet and investigate the number of paperclips the electromagnet can hold for an electromagnet with twenty loops of wire versus one with forty loops of wire. A six to twelve volt battery, a large nail or metal rod, and insulated wire are required for this activity. This is the fourth activity in the Exploring the Earth's Magnetic Field: An IMAGE Satellite Guide to the Magnetosphere educators guide.

  16. Sympathetic Sideband Cooling of CaH+

    NASA Astrophysics Data System (ADS)

    Rugango, Rene; Brown, Kenneth R.

    2014-06-01

    We demonstrate sympathetic Doppler cooling and our progress towards sideband cooling of a CaH+ ion co-trapped with a Ca+ atomic ion in a linear Paul trap. Molecular ions are generally difficult to laser cool due to a lack of closed electronic transitions as a result of vibrational and rotational states. Despite this challenge, they can be cooled indirectly through their Coulombic interaction with a fluorescent atomic ion that is being directly laser cooled. Ions are firstly Doppler cooled to get to the Lamb-Dicke regime, where the ion motion is small relative to the excitation wavelength and then sideband cooled reaching temperatures below 1 ?K. All the ions' axial modes (center of mass and breathing mode) and radial modes ( two center of mass and two tilt modes) are addressed, and the temperature is determined by examining the ratio of sidebands.

  17. Thermoelectric cooling and power generation

    PubMed

    DiSalvo

    1999-07-30

    In a typical thermoelectric device, a junction is formed from two different conducting materials, one containing positive charge carriers (holes) and the other negative charge carriers (electrons). When an electric current is passed in the appropriate direction through the junction, both types of charge carriers move away from the junction and convey heat away, thus cooling the junction. Similarly, a heat source at the junction causes carriers to flow away from the junction, making an electrical generator. Such devices have the advantage of containing no moving parts, but low efficiencies have limited their use to specialty applications, such as cooling laser diodes. The principles of thermoelectric devices are reviewed and strategies for increasing the efficiency of novel materials are explored. Improved materials would not only help to cool advanced electronics but could also provide energy benefits in refrigeration and when using waste heat to generate electrical power. PMID:10426986

  18. Conversion of an Electromagnetic Wave into a Periodic Train of Solitons under Cyclotron Resonance Interaction with a Backward Beam of Unexcited Electron-Oscillators

    NASA Astrophysics Data System (ADS)

    Zotova, I. V.; Ginzburg, N. S.; Sergeev, A. S.; Kocharovskaya, E. R.; Zaslavsky, V. Yu.

    2014-10-01

    The possibility of the conversion of intense continuous microwave radiation into a periodic train of short pulses by means of resonant interaction with a beam of unexcited cyclotron electron oscillators moving backward is shown. In such a system there is a certain range of parameters where the incident stationary signal splits into a train of short pulses and each of them can be interpreted as a soliton. It is proposed to use this effect for amplitude modulation of radiation of short wavelength gyrotrons.

  19. Excitation of high-frequency electromagnetic waves by energetic electrons with a loss cone distribution in a field-aligned potential drop

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.; Vinas, Adolfo F.

    1994-01-01

    The electron cyclotron maser instability (CMI) driven by momentum space anisotropy (df/dp (sub perpendicular) greater than 0) has been invoked to explain many aspects, such as the modes of propagation, harmonic emissions, and the source characteristics of the auroral kilometric radiation (AKR). Recent satellite observations of AKR sources indicate that the source regions are often imbedded within the auroral acceleration region characterized by the presence of a field-aligned potential drop. In this paper we investigate the excitation of the fundamental extraordinary mode radiation due to the accelerated electrons. The momentum space distribution of these energetic electrons is modeled by a realistic upward loss cone as modified by the presence of a parallel potential drop below the observation point. On the basis of linear growth rate calculations we present the emission characteristics, such as the frequency spectrum and the emission angular distribution as functions of the plasma parameters. We will discuss the implication of our results on the generation of the AKR from the edges of the auroral density cavities.

  20. Quantum modulation against electromagnetic interference

    E-print Network

    Juan Carlos Garcia-Escartin

    2014-11-26

    Periodic signals in electrical and electronic equipment can cause interference in nearby devices. Randomized modulation of those signals spreads their energy through the frequency spectrum and can help to mitigate electromagnetic interference problems. The inherently random nature of quantum phenomena makes them a good control signal. I present a quantum modulation method based on the random statistics of quantum light. The paper describes pulse width modulation schemes where a Poissonian light source acts as a random control that spreads the energy of the potential interfering signals. I give an example application for switching-mode power supplies and comment the further possibilities of the method.