Sample records for electromagnetics electron cooling

  1. Electronic Cooling in Graphene

    Microsoft Academic Search

    R. Bistritzer; A. H. MacDonald

    2009-01-01

    Energy transfer to acoustic phonons is the dominant low-temperature cooling channel of electrons in a crystal.For cold neutral graphene we find that the weak cooling power of its acoustical modes relative to the heat capacity of the system leads to a power law decay of the electronic temperature when far from equilibrium. For heavily doped graphene a high electronic temperature

  2. 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.

  3. 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.

  4. Electronic cooling in graphene.

    PubMed

    Bistritzer, R; MacDonald, A H

    2009-05-22

    Energy transfer to acoustic phonons is the dominant low-temperature cooling channel of electrons in a crystal. For cold neutral graphene we find that the weak cooling power of its acoustic modes relative to their heat capacity leads to a power-law decay of the electronic temperature when far from equilibrium. For heavily doped graphene a high electronic temperature is shown to initially decrease linearly with time at a rate proportional to n;{3/2} with n being the electronic density. The temperature at which cooling via optical phonon emission begins to dominate depends on graphene carrier density. PMID:19519053

  5. ELECTRON COOLING OF RHIC.

    SciTech Connect

    BEN-ZVI, I.; LITVINENKO, V.; BARTON, D.; ET AL.

    2005-05-16

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

  6. Computational electronics and electromagnetics

    SciTech Connect

    Shang, C C

    1998-01-01

    The Computational Electronics and Electromagnetics thrust area serves as the focal point for Engineering R and D activities for developing computer-based design and analysis tools. Representative applications include design of particle accelerator cells and beamline components; design of transmission line components; engineering analysis and design of high-power (optical and microwave) components; photonics and optoelectronics circuit design; electromagnetic susceptibility analysis; and antenna synthesis. The FY-97 effort focuses on development and validation of (1) accelerator design codes; (2) 3-D massively parallel, time-dependent EM codes; (3) material models; (4) coupling and application of engineering tools for analysis and design of high-power components; and (5) development of beam control algorithms coupled to beam transport physics codes. These efforts are in association with technology development in the power conversion, nondestructive evaluation, and microtechnology areas. The efforts complement technology development in Lawrence Livermore National programs.

  7. 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.

  8. Electronic cooling using thermoelectric devices

    NASA Astrophysics Data System (ADS)

    Zebarjadi, M.

    2015-05-01

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

  9. Electronics and Electromagnetism

    NASA Astrophysics Data System (ADS)

    Nièpce, J.-C.; Givord, D.

    Multilayer ceramic capacitors (MLCC) are the capacitors most commonly used in electronic circuits (television, radio, telephone, automobile, aeronautics, space, etc.). The main advantages are low cost, small size, a good level of chemical inertness, due to the fact that they are made from chemically very stable oxide ceramics, and hence good stability in time.

  10. Cooling Shelf For Electronic Equipment

    NASA Technical Reports Server (NTRS)

    Tanzer, Herbert J.

    1989-01-01

    Heat-pipe action cools and maintains electronics at nearly constant temperature. System designed to control temperatures of spacecraft shelves or baseplates by combining honeycomb sandwich panel with reservoir of noncondensable gas and processing resulting device as variable-conductance heat pipe. Device provides flat surface for mounting heat-dissipating electronics that is effectively cooled and maintained at nearly constant temperature. Potentially useful in freeze drying, refrigeration, and air conditioning.

  11. Peltier cooling of superconducting electronics

    Microsoft Academic Search

    J. W. Straehle; S. Rath; K.-J. Klingesberger; T. Nissel; S. G. Doettinger; C. A. Doettinger; R. P. Huebener; S. Kemmler-Sack

    1997-01-01

    The increase of the superconducting transition temperature in some of the cuprate superconductors to values higher than 130 K is generating strong interest in the exploration of Peltier cooling for the operation of superconducting electronics. In this case, we need materials with a sufficiently large figure of merit z down to temperatures near 100 K. We have performed measurements of

  12. Electromagnetic vacuum fluctuations and electron coherence

    Microsoft Academic Search

    L. H. Ford

    1993-01-01

    The coupling of the quantized electromagnetic field to coherent electrons is investigated. The effects both of photon emission and of the electromagnetic vacuum fluctuations upon electron interference are analyzed. The modifications of the vacuum fluctuations due to a conducting plate lead to a decrease in the amplitude of the interference oscillations. The possibility of observing this effect is discussed. It

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

    E-print Network

    Peles, Yoav

    -generation electronic systems, such as radar, di- rected-energy lasers, and electromagnetic weapons, will exceed 1000 WTwo-phase refrigerant flow instability analysis and active control in transient electronics cooling Accepted 26 July 2010 Available online 21 August 2010 Keywords: Electronics cooling Flow instability

  14. 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.

  15. 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.

  16. Electromagnetic vacuum fluctuations and electron coherence

    NASA Astrophysics Data System (ADS)

    Ford, L. H.

    1993-06-01

    The coupling of the quantized electromagnetic field to coherent electrons is investigated. The effects both of photon emission and of the electromagnetic vacuum fluctuations upon electron interference are analyzed. The modifications of the vacuum fluctuations due to a conducting plate lead to a decrease in the amplitude of the interference oscillations. The possibility of observing this effect is discussed. It is also shown that there is an analogue of the Aharonov-Bohm effect in which electron interference is sensitive to vacuum fluctutations in regions from which the electrons are excluded.

  17. Electromagnetic wave analogue of electronic diode

    E-print Network

    Shadrivov, Ilya V; Kivshar, Yuri S; Fedotov, Vassili A; Zheludev, Nikolay I

    2010-01-01

    An electronic diode is a nonlinear semiconductor circuit component that allows conduction of electrical current in one direction only. A component with similar functionality for electromagnetic waves, an electromagnetic isolator, is based on the Faraday effect of the polarization state rotation and is also a key component of optical and microwave systems. Here we demonstrate a chiral electromagnetic diode, which is a direct analogue of an electronic diode: its functionality is underpinned by an extraordinary strong nonlinear wave propagation effect in the same way as electronic diode function is provided by a nonlinear current characteristic of a semiconductor junction. The effect exploited in this new electromagnetic diode is an intensity-dependent polarization change in an artificial chiral metamolecule. This microwave effect exceeds a similar optical effect previously observed in natural crystals by more than 12 orders of magnitude and a direction-dependent transmission that differing by a factor of 65.

  18. Towards demonstration of electron cooling with bunched electron beam

    Microsoft Academic Search

    Fedotov

    2012-01-01

    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

  19. Electron kinetics in a cooling plasma

    SciTech Connect

    Helander, P.; Smith, H.; Fueloep, T.; Eriksson, L.-G. [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Department of Electromagnetics, Chalmers University of Technology, 412 96 Goeteborg (Sweden); Association Euratom-CEA, CEA/DSM/DRFC, Centre de Cadarache, 13108 Saint-Paul lez Durance (France)

    2004-12-01

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

  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. ELECTRON COOLING IN THE RECYCLER COOLER

    SciTech Connect

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

    2007-09-10

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

  2. News in Electron Cooling: Highlights from ECOOL'99

    Microsoft Academic Search

    D. Reistad

    2000-01-01

    A Workshop on Electron Cooling and Related Topics was organised in Uppsala, Sweden, from 19 to 22 May 1999. The workshop, which incorporated the 5th Workshop on Medium Energy Electron Cooling, included papers on theory, technology, limitations and applications of electron cooling as well as papers on laser cooling and stochastic pre-cooling. The last day of the workshop was devoted

  3. Toward multi-GeV electron cooling

    NASA Astrophysics Data System (ADS)

    Larson, D. J.; Cline, D. B.; Anderson, D. R.; Adney, J. R.; Sundquist, M. L.; Mills, F. E.

    1986-10-01

    We discuss progress being made in the development of an ampere intensity MeV recirculating electron beam system. The system is presently intended for the upgrading of antiproton sources, but is also ideally suited for ion beam cooling in the GeV energy range. We present results of a theoretical study applying intermediate energy electron cooling in to the Fermilab antiproton source, a brief overview of the design of the electron cooler, and discuss progress on the assembly and test of the system.

  4. Thermoelectric cooler application in electronic cooling

    Microsoft Academic Search

    Reiyu Chein; Guanming Huang

    2004-01-01

    This study addresses thermoelectric cooler (TEC) applications in the electronic cooling. The cold side temperature (Tc) and temperature difference between TEC cold and hot sides (?T=Th?Tc, Th=temperature of hot side of TEC) were used as the parameters. The cooling capacity, junction temperature, coefficient of performance (COP) of TEC and the required heat sink thermal resistance at the TEC hot side

  5. 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.

  6. 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).

  7. 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.

  8. 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.

  9. Electronic systems failures and anomalies attributed to electromagnetic interference

    NASA Astrophysics Data System (ADS)

    Leach, R. D.; Alexander, M. B.

    1995-07-01

    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.

  10. Cooling of electronics in collider experiments

    SciTech Connect

    Richard P. Stanek et al.

    2003-11-07

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

  11. Influence of electron beam parameters on coherent electron cooling

    SciTech Connect

    Wang G.; Hao, Y.; Litvinenko, V.N.; Webb, S.

    2012-05-20

    Coherent electron cooling (CeC) promises to revolutionize the cooling of high energy hadron beams. The intricate dynamics of the CeC depends both on the local density and energy distribution of the beam. The variations of the local density (beam current) are inevitable in any realistic beam. Hence, in this paper we propose a novel method of beam conditioning. The conditioning provides compensation of effect from such variation by a correlated energy modulation. We use our analytical FEL model for an electron bunch with Gaussian line charge density and cosine-type energy variation along bunch. We analyze the phase variation between the electron density modulation at the exit of the FEL-amplifier and the ions inducing it in the modulator as a function of the peak current and the electron beam energy. Based on this analysis, electron bunch parameters for optimal CeC cooling are found numerically.

  12. Fluctuating electromagnetic fields and electron coherence

    NASA Astrophysics Data System (ADS)

    Hsiang, Jen-Tsung

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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Electron Cooling Performance at IMP Facility

    E-print Network

    Xiaodong, Yang

    2011-01-01

    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 o...

  18. Electromagnetic Turbulence Simulations with Kinetic Electrons

    NASA Astrophysics Data System (ADS)

    Parker, Scott E.

    2003-10-01

    Recently a new electromagnetic kinetic electron delta-f particle simulation model has been demonstrated to work well at large values of plasma beta times the ion-to-electron mass ratio [1,2]. The new simulation presented here uses a generalized split-weight scheme [3,4], where the adiabatic part is adjustable, along with a parallel canonical momentum formulation [5] and has been developed in three-dimensional toroidal flux-tube geometry. The model also includes electron-ion collisional effects and has been linearly benchmarked with continuum codes [6,7]. Electromagnetic simulations with kinetic electrons require a timestep approximately one-half that of electrostatic adiabatic electron simulations. Large box size simulations of 256 by 256 in units of ion gyroradius using a realistic mass ratios run well and detailed convergence studies have been done. Finite-beta reduction of energy transport, below the adiabatic electron level is observed for betas below the kinetic ballooning limit. For beta above the kinetic ballooning threshold fluxes are extremely high, and it is unlikely to be an experimentally relevant regime. Zonal flows with kinetic electrons are found to be turbulent with the spectrum peaking at zero and having a width in the frequency range of the driving turbulence. This is in contrast with adiabatic electron cases where the zonal flows are near stationary. We have shown that the linear behavior of the zonal flow is not significantly affected by kinetic electrons. Zonal fields [9] are found to be very weak consistent with theoretical predictions for betas below the kinetic ballooning limit. Detailed spectral and cross-correlation analysis of the turbulent spectra will be presented in the various limits. Acknowledgments: Thanks to A.M. Dimits, D. Shumaker, LLNL; V.K. Decyk, J.N. Leboeuf UCLA, work done using the Summit Framework and supported by the DOE SciDAC Plasma Microturbulence Project. [1] Y. Chen and S.E. Parker, to appear in J. Comput. Phys. (2003). [2] Y. Chen, S.E. Parker, B.I. Cohen, A.M. Dimits, W.M. Nevins, D. Shumaker, V.K. Decyk and J.N. Leboeuf, to appear in Nuc. Fusion (2003). [3] I. Manuilskiy and W.W. Lee, Phys. Plasmas 7 1381 (2000). [4] Y. Chen and S.E. Parker, Phys. Plasmas 8 2095 (2001) [5] T.S. Hahm, W.W. Lee and A. Brizard, Phys. Fluids 31 1940 (1988). [6] W. Dorland et. al, Proc. 18th Int. Conf. on Fusion Energy, IAEA, Sorrento, Italy, 2000; W. Dorland, F. Jenko, M. Kotschenreuther and B.N. Rogers, Phys. Rev. Lett. 85, 5336 (2000). [7] J. Candy and R. Waltz, to appear in J. Comput. Physics (2003). [8] A.V. Gruzinov and P.H. Diamond, Phys. Plasmas 3 1854 (1996), L. Chen, Z. Lin R.B. White and F. Zonca, Nuc. Fusion 41 747 (2001); P.N. Gudzar, R.G. Kleva, A. Das and P.K. Kaw, Phys. Plasmas 8 3907 (2001).

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

    Microsoft Academic Search

    2005-01-01

    In order to meet the Department of Energy's (DOE's) FreedomCAR and Vehicle Technologies (FVCT) goals for volume, weight, efficiency, reliability, and cost, the cooling of the power electronic devices, traction motors, and generators is critical. Currently the power electronic devices, traction motors, and generators in a hybrid electric vehicle (HEV) are primarily cooled by water-ethylene glycol (WEG) mixture. The cooling

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

    E-print Network

    Measurement of Electromagnetic Radiation Emitted during Rapid Intramolecular Electron Transfer the electromagnetic (EM) waveform broadcast by the charge-transfer process itself. Intermolecular and intramo- lecular antenna, broadcasting its dynamics by emitting an EM transient as charge moves between donor (D

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

    E-print Network

    Paris-Sud XI, Université de

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

  2. Influence of electromagnetic fluctuations on the resonant tunneling of electrons

    Microsoft Academic Search

    H. T. Imam; V. V. Ponomarenko; D. V. Averin

    1995-01-01

    We have considered the influence of electromagnetic fluctuations on electron tunneling via one non-degenerate resonant level, the problem that is relevant for electron transport through quantum dots in the Coulomb blockade regime. We show that the overall effect of the fluctuations depends on whether the electron bands in external electrodes are empty or filled. In the empty band case, depending

  3. 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

  4. 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.

  5. 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 Stöneberg. Thanks to Server Technology, Inc. who provided power measurement and distribution for this project. #12;ii ABSTRACT This report documents a demonstration of an electronic

  6. Electron diffusion in intense high frequency electromagnetic fields

    Microsoft Academic Search

    S. Bhattacharjee; I. Dey; S. Jain; H. Amemiya

    The phenomenon of electron diffusion in a background gas, in the presence of high frequency electromagnetic fields is investigated. Monte-Carlo simulation procedures were applied to determine the number of collisions N. The dependence of N on the externally controllable parameters like the electron-neutral mean free path ? and the characteristic diffusion length ? (determined by the geometry) were studied. It

  7. 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.

  8. News in Electron Cooling: Highlights from ECOOL'99

    NASA Astrophysics Data System (ADS)

    Reistad, D.

    2000-06-01

    A Workshop on Electron Cooling and Related Topics was organised in Uppsala, Sweden, from 19 to 22 May 1999. The workshop, which incorporated the 5th Workshop on Medium Energy Electron Cooling, included papers on theory, technology, limitations and applications of electron cooling as well as papers on laser cooling and stochastic pre-cooling. The last day of the workshop was devoted to so-called Medium (2Electron Cooling. Reports on measurements and achievements made at a number of electron cooling facilities, including the most recently completed ones, i.e. at SIS (GSI, Darmstadt) and at AD (CERN), were given. There were also reports on electron coolers under construction at the National Institute of Radiological Science (NIRS) at Chiba in Japan and at the Heavy Ion Research Facility (HIRFL) in Lanzhou, China. Work on medium and high-energy electron cooling at FNAL, DESY, and JINR was presented.

  9. 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.

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

    E-print Network

    Boyer, Edmond

    ISEF 2007 - XIV International Symposium on Electromagnetic Fields in Mechatronics, Electrical International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, Arras : France (2009)" #12;ISEF 2007 - XIV International Symposium on Electromagnetic Fields in Mechatronics

  11. 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.

  12. Electron cooling by arrays of submicron tunnel junctions

    Microsoft Academic Search

    R. Leoni; G. Arena; M. G. Castellano; G. Torrioli

    1999-01-01

    We cooled down the electrons of a 3 mum3 copper strip by using an on-chip electronic microcooler made by a superconductor-insulator-normal-insulator-superconductor (SINIS) structure. We obtained an electron temperature drop DeltaT~=-10 mK at a temperature of the bath slightly above Tb=500 mK and we estimated a cooling power slightly larger than 20 pW at this temperature. In contrast to previous experiments,

  13. Electromagnetic environmental impact of power electronics equipment

    Microsoft Academic Search

    RICHARD REDL

    2001-01-01

    A dramatic increase in the number of line-powered electronic equipment (computers and other office equipment, electronic ballasts, variable-speed drives, and consumer electronics, e.g., color televisions) has taken place. These items of equipment draw distorted, and often fluctuating, line current; they also generate high-frequency conducted and radiated noise due to the sharp edges of the waveforms characteristic of the switching power

  14. Advances in electron cooling in heavy-ion storage rings

    SciTech Connect

    Danared, H. [Stockholm Univ., (Sweden)

    1994-12-31

    The efficiency of electron cooling can be improved by reducing the temperature of the electrons. If the magnetic field at the location of the electron gun is stronger than in the region where the electrons interact with the ions, and the field gradient is adiabatic with respect to the cyclotron motion of the electrons, the resulting expansion of the electron beam reduces its transverse temperature by a factor equal to the ratio between the two fields. A ten times expanded electron beam was introduced in the CRYRING electron cooler in the summer of 1993, and similar arrangements have since then been made at the TSR ring in Heidelberg and at ASTRID in Aarhus. The reduction of the transverse electron temperature has increased cooling rates with large factors, and improves the energy resolution and increases count rates when the cooler is used as an electron target for ion-electron recombination experiments.

  15. Prospects for Peltier cooling of superconducting electronics

    Microsoft Academic Search

    R. P Huebener; C. C Tsuei

    1998-01-01

    We report on a Peltier cooling experiment using commercially available Peltier modules and reaching 149K on the cold end. On the warm end the temperature was fixed at 282K by cooling water. For reaching the superconducting transition temperature of the cuprates, better thermoelectric materials must be developed. We discuss estimates of the figure of merit needed for achieving the operating

  16. Electromagnetic and thermal analysis of distributed cooled high power millimeter wave windows

    Microsoft Academic Search

    Scott D. Nelson; Thomas Reitter; Malcolm Caplan; Charles Moeller

    1996-01-01

    The sectional high-frequency internally-cooled window, as proposed by General Atomics(1), has unique potential for allowing microwave sources to reach multi-megawatt CW levels with application to ECRH. Designs are being investigated using computational electromagnetic (EM), thermal, and mechanical codes at 110 GHz and 170 GHz to examine the design tradeoffs between RF performance and thermal mechanical safety margins. The EM analyses

  17. Electromagnetic and thermal analysis of distributed cooled high power millimeter wave windows

    Microsoft Academic Search

    S. D. Nelson; T. Reitter; M. Caplan

    1995-01-01

    The sectional high-frequency internally-cooled window, as proposed by General Atomics, has unique potential for allowing microwave sources to reach multi-megawatt CW levels with application to ECRH. Designs are being investigated using computational electromagnetic (EM), thermal, and mechanical codes at 110 GHz and 170 GHz to examine the design tradeoffs between RF performance and thermal mechanical safety margins. The EM analyses

  18. 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

  19. 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.

  20. Coupling of ESD-generated EMP (electromagnetic pulse) to electronics

    SciTech Connect

    Boverie, B.

    1988-01-01

    Electrostatic discharges (ESD) can generate an electromagnetic pulse (EMP) which can couple into electronic circuits. Analytical and experimental models of this coupling demonstrate that, under some circumstances, the energy coupled to an integrated circuit on a printed circuit board is proportional to the product of the peak E- field and the derivative of the E-field. 4 refs., 3 figs.

  1. Qubit logic modeling by electronic circuits and electromagnetic signals

    E-print Network

    G. A. Kouzaev

    2001-08-07

    In the paper an approach is presented allowing to model quantum logic circuits by electronic gates for discrete spatially modulated electromagnetic signals. The designed circuitry is for modeling low scale quantum nets of general design and quantum devices based only on superposition principle of their work.

  2. Electron beam injection during active experiments. 1. Electromagnetic wave emissions

    Microsoft Academic Search

    R. M. Winglee; P. J. Kellogg

    1990-01-01

    During the active injection of an electron beam, a broad spectrum of waves is generated. In this paper examples of spectra from the recent Echo 7 experiment are presented. These results show that the characteristics of the emissions can change substantially with altitude. Two-dimensional (three velocity) relativistic electromagnetic particle simulations are used to investigate the changes in the plasma conditions

  3. Nonlinear electromagnetic waves in electron-positron plasmas

    Microsoft Academic Search

    N. F. Cramer

    Plasmas with unequal numbers of electrons and positrons are of interest for pulsar magnetospheres and laboratory pair plasma experiments. Here the dispersion relation for electromagnetic waves in such a plasma is discussed, and the types of nonlinear waves that arise on the various branches of the dispersion curves. An excess of one type of charge carrier leads to circular and

  4. Electromagnetic Interference Generated from Fast Switching Power Electronic Devices

    Microsoft Academic Search

    K. M. Muttaqi; M. E. Haque

    2008-01-01

    This paper investigates the negative effects of electromagnetic interference (EMI) due to fast switching power devices (high dv\\/dt and di\\/dt) used in power electronic converters and industrial equipment. Mitigation techniques have been explored to reduce EMI noise effectively. Remedial measures to reduce the risk of equipment malfunction and health risk due to EMI have been explored. In this paper, EMI

  5. Electron spin precession in the field of an electromagnetic wave

    Microsoft Academic Search

    V. V. Tikhomirov

    2003-01-01

    The solution of the Dirac equation for an electron in the field of a plane circularly polarized electromagnetic wave having\\u000a an arbitrary intensity and a phase velocity v\\u000a ph different from the speed of light c is obtained. This solution is shown to describe the previously unknown effect of electron spin precession that exceeds the\\u000a known precession effects caused by

  6. Large amplitude solitary electromagnetic waves in electron-positron plasmas

    Microsoft Academic Search

    Frank Verheest; Tom Cattaert

    2004-01-01

    Waves in electron-positron plasmas have fundamentally different dispersion characteristics due to the equal charge-to-mass ratios between negative and positive charges, which mix different timescales, and are of interest in understanding aspects of pulsars and active galactic nuclei, where astrophysical electron-positron plasmas occur. Earlier systematic nonlinear treatments of parallel propagating electromagnetic waves via a reductive perturbation analysis had indicated unusual results,

  7. 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.

  8. Corona driven air propulsion for cooling of electronics

    Microsoft Academic Search

    F. Yang; N. E. Jewell-Larsen; D. L. Brown; K. Pendergrass; D. A. Parker; I. A. Krichtafovitch; A. V. Mamishev

    The possibility of building a high voltage electrostatic air pump for cooling of microelectronics is investigated. Existing cooling technology no longer provides adequate heat dissipation due to excessive heat generation caused by the growing component density on electronic devices. Heat sink fins are packed more closely to increase the heat exchange surface area, resulting in narrower channels between the fins.

  9. C-AD electron-cooling Photocathode and Laser

    E-print Network

    availability ­ Modifications needed · Diamond amplifier ­ Theoretical analysis ­ Gain measurements ­ RF testing ­ Capsule fabrication · Brazing · Metallization #12;C-AD electron-cooling Overview Photocathode Requirements-cooling 9.4 MHz 532 nm, 355 nm 10 ps pulse length Synchronized to master RF clock Adjustable output power

  10. Progress on Analytical Modeling of Coherent Electron Cooling

    SciTech Connect

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

    2010-05-23

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

  11. Cooling of cryogenic electron bilayers via the Coulomb interaction

    E-print Network

    John King Gamble; Mark Friesen; Robert Joynt; S. N. Coppersmith

    2011-04-13

    Heat dissipation in current-carrying cryogenic nanostructures is problematic because the phonon density of states decreases strongly as energy decreases. We show that the Coulomb interaction can prove a valuable resource for carrier cooling via coupling to a nearby, cold electron reservoir. Specifically, we consider the geometry of an electron bilayer in a silicon-based heterostructure, and analyze the power transfer. We show that across a range of temperatures, separations, and sheet densities, the electron-electron interaction dominates the phonon heat-dissipation modes as the main cooling mechanism. Coulomb cooling is most effective at low densities, when phonon cooling is least effective in silicon, making it especially relevant for experiments attempting to perform coherent manipulations of single spins.

  12. Cooling of cryogenic electron bilayers via the Coulomb interaction

    E-print Network

    Gamble, John King; Joynt, Robert; Coppersmith, S N

    2011-01-01

    Heat dissipation in current-carrying cryogenic nanostructures is problematic because the phonon density of states decreases strongly as energy decreases. We show that the Coulomb interaction can prove a valuable resource for carrier cooling via coupling to a nearby, cold electron reservoir. Specifically, we consider the geometry of an electron bilayer in a silicon-based heterostructure, and analyze the power transfer. We show that across a range of temperatures, separations, and sheet densities, the electron-electron interaction dominates the phonon heat-dissipation modes as the main cooling mechanism. Coulomb cooling is most effective at low densities, when phonon cooling is least effective in silicon, making it especially relevant for experiments attempting to perform coherent manipulations of single spins.

  13. Cooling of cryogenic electron bilayers via the Coulomb interaction

    NASA Astrophysics Data System (ADS)

    Gamble, John King; Friesen, Mark; Joynt, Robert; Coppersmith, S. N.

    2011-09-01

    Heat dissipation in current-carrying cryogenic nanostructures is problematic because the phonon density of states decreases strongly as energy decreases. We show that the Coulomb interaction can prove a valuable resource for carrier cooling via coupling to a nearby cold electron reservoir. Specifically, we consider the geometry of an electron bilayer in a silicon-based heterostructure and analyze the power transfer. We show that, across a range of temperatures, separations, and sheet densities, the electron-electron interaction dominates the phonon heat-dissipation modes as the main cooling mechanism. Coulomb cooling is most effective at low densities, when phonon cooling is least effective in silicon, making it especially relevant for experiments attempting to perform coherent manipulations of single spins.

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

    E-print Network

    Paris-Sud XI, Université de

    ISEF 2009 - XIV International Symposium on Electromagnetic Fields in Mechatronics, Electrical 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, France

  15. 49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section...Systems General § 236.8 Operating characteristics of electromagnetic, electronic, or electrical apparatus. Signal...

  16. 49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section...Systems General § 236.8 Operating characteristics of electromagnetic, electronic, or electrical apparatus. Signal...

  17. 49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section...Systems General § 236.8 Operating characteristics of electromagnetic, electronic, or electrical apparatus. Signal...

  18. 49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2010-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section...Systems General § 236.8 Operating characteristics of electromagnetic, electronic, or electrical apparatus. Signal...

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section...Systems General § 236.8 Operating characteristics of electromagnetic, electronic, or electrical apparatus. Signal...

  20. 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.

  1. Radiative recombination of ions and nuclei in electron cooling systems

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. B.; Meshkov, I. N.; Philippov, A. V.

    2012-07-01

    Experimental data on rates for the radiative recombination of nuclei (from helium to uranium) and various ions in interaction with an electron beam in electron cooling systems are reviewed. An analysis of the experimental data has yielded the dependence of the radiative recombination rate on the relative electron energy appreciably differently than the theoretical models obtained earlier by H. Kramers and R. Schuch. In addition, it is shown that the radiative recombination rate of nuclei in the experiment depends on the transverse electron energy as T {?/-0.82},which is also different from the results of the calculations by the theoretical model proposed by M. Bell and J. Bell. Experimental data on the cooling of ions in intermediate charge states are analyzed and the dependence of the radiative recombination rate on the charge state of the ion (electron-shell configuration) is shown. For some ion charge states, the rate of the process is of a resonance character. Loss to radiative recombination in the electron cooling system of the NICA Booster is evaluated for the Au32+, Au33+, Au50+, and Au51+ ion beams. Limitations imposed on the Au79+ beam lifetime by radiative recombination in the electron cooling system of the NICA Collider are analyzed. Possible ways to decrease the radiative recombination rate of nuclei by selecting the parameters of the electron cooling system for the NICA Collider are proposed.

  2. 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.

  3. Superconducting shield for solenoid of electron cooling system

    NASA Astrophysics Data System (ADS)

    Agapov, N. N.; Donets, D. E.; Drobin, V. M.; Kulikov, E. A.; Malinovski, H.; Pivin, R. V.; Smirnov, A. V.; Prokofichev, Yu. V.; Trubnikov, G. V.; Dorofeev, G. L.

    2012-07-01

    Ensuring the high homogeneity of a magnetic field in the straight solenoid of an electron cooling system is a very important task. In the electron cooling system of the collider in the NICA project, it is planned to use superconducting solenoids for the generation of a longitudinal magnetic field. Using of the superconducting shield is proposed to achieve the required homogeneity of the magnetic field in the cooling section. This article discusses the design of the superconducting shield and presents experimental and numerical studies into the homogeneity of the magnetic field in solenoids with the superconducting shield.

  4. 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

  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. Emerging Two-Phase Cooling Technologies for Power Electronic Inverters

    SciTech Connect

    Hsu, J.S.

    2005-08-17

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

  7. Cooling System Design for a Split High Field Bitter-type Electromagnet

    NASA Astrophysics Data System (ADS)

    Birmingham, William; Bates, Evan; Romero-Talamas, Carlos; Rivera, William

    2014-10-01

    For the purpose of analyzing magnetized dusty plasma at the University of Maryland Baltimore County (UMBC), we are designing a split resistive electromagnet. When completed, the magnet will be capable of generating fields of 10 T for 10 seconds. The type of design proposed here was originally developed by Francis Bitter, and achieves high magnetic fields by helically stacked disk-shaped solenoids with axially oriented cooling channels. In order to ensure the safety and functionality of the apparatus, the geometry and placement of the cooling passages must be designed to establish a manageable temperature profile throughout the coil. The estimated power consumption from resistive losses is nearly 7 MW, thus it is imperative to optimize the cooling capacity of the system. The cooling capacity is limited by the mass of chilled water available at one time and the maximum achievable mass flow through the coils. The system is also designed to withstand the resultant mechanical stresses from the Lorentz force. Slot-shaped cooling channels are used. The number and placement of these channels is optimized through an iterative and integrated design process which combines analytic calculations with finite element analyses. The methodology and results of the design process is presented.

  8. An electrohydrodynamic polarization micropump for electronic cooling

    Microsoft Academic Search

    J. Darabi; M. M. Ohadi; D. DeVoe

    2001-01-01

    This paper presents the design, fabrication, and characterization of an innovative microcooling device for microelectronics applications. The device incorporates an active evaporative cooling surface, a polarization micropump, and temperature sensors into a single chip. The micropump provides the required pumping action to bring the working fluid to the evaporating surface, allowing the effective heat transfer coefficient through a thin-film evaporation\\/boiling

  9. An electromagnetically focused electron beam line source

    NASA Astrophysics Data System (ADS)

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

    2003-11-01

    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 field of 50 G was employed to obtain a well-focused electron beam at a deflection of 180°, with cathode to work site distance of 130 mm. Dimensions of the beam (1.25×120 mm) recorded at the work site were found to be in good agreement with the designed length of cathode. The deformation of the cathode was overcome by introducing a spring action mechanism, which gives uniform emission current density throughout the emission surface. We have achieved the saturation limit of the designed source resulting in smooth and swift operation of the gun for many hours (10-15 h continuously). The design of gun is so simple that it can accommodate longer cathodes for obtaining higher emission values. This gun has made it possible to coat large substrate surfaces at much faster evaporation rate at lower cost. It can also be useful in large-scale vacuum metallurgy plants for melting, welding and heat treatment.

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

    E-print Network

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

    2013-01-01

    We present the radio observations and modeling of an optically bright Type II-P supernova (SN), SN 2012aw which exploded in the nearby galaxy Messier 95 (M95) at a distance of $10\\ \\rm Mpc$. The spectral index values calculated using $C$, $X$ & $K$ bands are smaller than the expected values for optically thin regime. During this time the optical bolometric light curve stays in the plateau phase. We interpret the low spectral index values to be a result of electron cooling. On the basis of comparison between Compton cooling timescale and Synchrotron cooling timescale we find that inverse Compton cooling process dominates over synchrotron cooling process. We therefore model the radio emission as synchrotron emission from a relativistic electron population with a high energy cutoff. The cutoff is determined by comparing the electron cooling time scale $t_{cool}$ and the acceleration time scale $\\tilde t_{acc}$. We constrain the mass loss rate in the wind ($\\dot M\\sim 1.9\\times10^{-6}\\ \\rm M_{\\odot}yr^{-1}$) ...

  11. Cooling of small electronic devices by boiling under microgravity

    NASA Astrophysics Data System (ADS)

    Straub, J.; Winter, J.; Picker, G.; Zell, M.

    The boiling heat transfer on a miniature heater has been measured under microgravity conditions during the IML 2 mission and under earth gravity after the mission in 1994. These experiments are simulations for the direct cooling of small electronic devices by boiling heat transfer, which becomes very important due to high thermal loads of modern electronic components.

  12. Electromagnetic solitons in degenerate relativistic electron–positron plasma

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  13. Electromagnetic wave pumped ion-channel free electron laser

    Microsoft Academic Search

    Liu Shenggang; R. J. Barker; Gao Hong; Yan Yang

    2001-01-01

    Theoretical study of electromagnetic wave pumped ion-channel free-electron laser (EPIC-FEL) is presented. The physical mechanism responsible for the generation of coherent radiation in the EPIC-FEL is described and the fundamental role of the ponderomotive wave in bunching and trapping the beam is emphasized. The dispersion relation of the EPIC-FEL has been obtained and growth rates are calculated for different parameters.

  14. Frequency mixing in scattering of electromagnetic waves by free electrons

    Microsoft Academic Search

    H. Prakash; Vachaspati

    1968-01-01

    Summary  It is shown that if the incident electromagnetic wave contains two frequencies, the wave scattered from free electrons contains\\u000a a complete spectrum of the combination frequencies in addition to the fundamentals, second harmonics and summation and beat\\u000a frequencies. The expressions for the scattering cross-sections of the summation and beat frequencies differ from those of\\u000a Fried and Frank but are in

  15. Modeling and simulation of electromagnetic wave propagation in electronic packages

    Microsoft Academic Search

    Danwei Xue

    1997-01-01

    In this dissertation, some research involving signal integrity analysis in electronic packages and printed circuit boards is introduced. Emphasis is concentrated on the modeling, parameter extraction, and simulation techniques related to the electromagnetic wave propagation in multi-layered power and ground plane structures. One aspect of the research covers parameter extraction of multi-conductor multi-layered transmission lines. Suggestions are given for using

  16. 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.

  17. Self-Consistent Electromagnetic Modeling of Electron Sources

    SciTech Connect

    Hess, Mark [Indiana University Cyclotron Facility, 2401 Milo B. Sampson Lane, Bloomington, Indiana 47408 (United States)

    2006-11-27

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

  18. Electromagnetic and thermal analysis of distributed cooled high power millimeter wave windows

    NASA Astrophysics Data System (ADS)

    Nelson, Scott D.; Reitter, Thomas; Caplan, Malcolm; Moeller, Charles

    1996-02-01

    The sectional high-frequency internally-cooled window, as proposed by General Atomics(1), has unique potential for allowing microwave sources to reach multi-megawatt CW levels with application to ECRH. Designs are being investigated using computational electromagnetic (EM), thermal, and mechanical codes at 110 GHz and 170 GHz to examine the design tradeoffs between RF performance and thermal mechanical safety margins. The EM analyses are for the window, under vacuum at one MW and includes variations in the shapes of the cooling fins, the surface treatment of the window elements themselves, the cooling fin tip treatment, the window pitch angle, and the waveguide effects. One advantage of the distributed cooled window is it's extensibility to higher power levels. Results in the modeling efforts are presented showing the EM field concentrations (which then will feed into the thermal analysis), the energy scattering/reflection, the transmitted launch angle variation as a function of physical geometry, and the spatial energy distribution and loss as a function of time and position.

  19. Electromagnetic and thermal analysis of distributed cooled high power millimeter wave windows

    NASA Astrophysics Data System (ADS)

    Nelson, S. D.; Reitter, T.; Caplan, M.

    1995-05-01

    The sectional high-frequency internally-cooled window, as proposed by General Atomics, has unique potential for allowing microwave sources to reach multi-megawatt CW levels with application to ECRH. Designs are being investigated using computational electromagnetic (EM), thermal, and mechanical codes at 110 GHz and 170 GHz to examine the design tradeoffs between RF performance and thermal mechanical safety margins. The EM analyses are for the window, under vacuum at one MW and includes variations in the shapes of the cooling fins, the surface treatment of the window elements themselves, the cooling fin tip treatment, the window pitch angle, and the waveguide effects. One advantage of the distributed cooled window is it's extensibility to higher power levels. Results in the modeling efforts are presented showing the EM field concentrations (which then will feed into the thermal analysis), the energy scattering/reflection, the transmitted launch angle variation as a function of physical geometry, and the spatial energy distribution and loss as a function of time and position.

  20. Electromagnetic instability in an electron beam-ion channel system

    SciTech Connect

    Su, D.; Tang, C. J. [Department of Applied Physics, Sichuan University, P.O. Box 54, Chengdu 610065 (China)

    2009-05-15

    The transverse electromagnetic instability in the electron beam-ion channel system is investigated using kinetic theory. The equilibrium distribution function of a relativistic electron beam, which takes into account a strong ion channel effect, is obtained. The linearized Vlasov equation is solved and the dispersion relation of the system is derived by perturbing the equilibrium with a high frequency electromagnetic wave (EMW). Analysis of the dispersion relation shows that the coupling of the electron beam with the transverse high frequency EMW is achieved through the deflection of the beam electrons due to the synergistic effects of the transverse high frequency EMW and transverse betatron oscillation. The numerical calculation finds that a branch of slow wave instability (SWI) with a wide frequency band is excited. The attenuation index of the SWI increases and its frequency band broadens as the normalized beam radii increases. Besides, the SWI will be suppressed as the longitudinal velocity of the electron beam increases to a certain value; meanwhile, a bunch of fast wave instability (FWI) is excited, which is equal to the increase of the relativistic factor. Also both the SWI and the FWI reach maximum when the EMW frequency meets a resonance condition.

  1. 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.

  2. Electromagnetic forces on plasmonic nanoparticles induced by fast electron beams

    NASA Astrophysics Data System (ADS)

    Reyes-Coronado, Alejandro; Barrera, Rubén G.; Batson, Philip E.; Echenique, Pedro M.; Rivacoba, Alberto; Aizpurua, Javier

    2010-12-01

    The total momentum transfer from fast electron beams, like those employed in scanning transmission electron microscopy (STEM), to plasmonic nanoparticles is calculated. The momentum transfer is obtained by integrating the electromagnetic forces acting on the particles over time. Numerical results for single and dimer metallic nanoparticles are presented, for sizes ranging between 2 and 80 nm. We analyze the momentum transfer in the case of metallic dimers where the different relevant parameters such as particle size, interparticle distance, and electron beam impact parameter are modified. It is shown that depending on the specific values of the parameters, the total momentum transfer yields a force that can be either attractive or repulsive. The time-average forces calculated for electron beams commonly employed in STEM are on the order of piconewtons, comparable in magnitude to optical forces and are thus capable of producing movement in the nanoparticles. This effect can be exploited in mechanical control of nanoparticle induced motion.

  3. Cooling technology for electronic equipment; Proceedings of the International Symposium, Honolulu, HI, Mar. 1987

    Microsoft Academic Search

    Win Aung

    1988-01-01

    Design and applications aspects of electronic-hardware cooling systems are examined in reviews and reports. Topics addressed include natural-convection air-cooling techniques, forced-convection air-cooling techniques, liquid cooling techniques, conduction cooling and internal resistances, thermal analysis and computer modeling, and thermal systems in electronic equipment. Diagrams, drawings, graphs, photographs, and tables of numerical data are provided.

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

    SciTech Connect

    Yadav, Naveen; Ray, Alak [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Chakraborti, Sayan [Institute for Theory and Computation, Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Stockdale, Christopher [Marquette University, Milwaukee, WI 53233 (United States); Chandra, Poonam [National Center for Radio Astronomy-TIFR, Pune 411007 (India); Smith, Randall [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Roy, Rupak; Bose, Subhash [Aryabhhata Research Institute of Observational Sciences, Nainital 263129 (India); Dwarkadas, Vikram [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Sutaria, Firoza [Indian Institute of Astrophysics, Bangalore 560034 (India); Pooley, David, E-mail: nyadav@tifr.res.in, E-mail: akr@tifr.res.in [Department of Physics, Sam Houston State University, Huntsville, TX 77341 (United States)

    2014-02-10

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

  5. Electron cooling in decaying low-pressure plasmas.

    PubMed

    Celik, Yusuf; Tsankov, Tsanko V; Aramaki, Mitsutoshi; Yoshimura, Shinji; Luggenhölscher, Dirk; Czarnetzki, Uwe

    2012-04-01

    A simple analytical fluid dynamic model is developed for evaporative electron cooling in a low-pressure decaying plasma and compared to a two-dimensional simulation and experimental data for the particular case of argon. Measured electron temperature and density developments are fully reproduced by the ab initio model and the simulation. Further, it is shown that in the late afterglow thermalization of electrons occurs by coupling to the ion fluid via Coulomb collisions at sufficiently high electron densities and not by coupling to the neutral background. PMID:22680586

  6. Thermal Design of Immersion Cooling Modules for Electronic Components

    Microsoft Academic Search

    Avram Bar-Cohen

    1981-01-01

    Direct immersion of electronic components in low-boiling point, dielectric fluids can provide a benign local ambience and accommodate substantial spatial and temporal power variations while minimizing component temperature excursions and failure rates. Following a review of possible immersion cooling configurations and the thermal mechanisms active in vapor-space and submerged condenser modules, attention is focused on the operational limits and relations

  7. Development of the micro capillary pumped loop for electronic cooling

    Microsoft Academic Search

    Seok-Hwan Moon; Gunn Hwang

    2007-01-01

    Electronic devices have been minimized but the performance of those is becoming better and better. Therefore it is needed to develop new cooling methods suitable for a thin packaging structure with high thermal density. The thin flat plate type micro CPL(capillary pumped loop) with the thickness less than 2 mm was developed in this study. The proposed micro CPL has

  8. Influence of Electron Evaporative Cooling on Ultracold Plasma Expansion

    E-print Network

    Wilson, Truman; Roberts, Jacob

    2013-01-01

    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. At lower densities (less than 10$^8$ /cm$^3$), evaporative cooling has a significant influence on the UCP expansion rate. 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.

  9. Ballistic electron transport in semiconductor heterostructures and its analogies in electromagnetic propagation in general dielectrics

    Microsoft Academic Search

    G. N. Henderson; T. K. Gaylord; E. N. Glytsis

    1991-01-01

    A comprehensive set of analogies between ballistic electron wave propagation in semiconductors (arbitrary kinetic energy and effective mass) and electromagnetic propagation in general dielectrics (arbitrary permittivity and permeability) is established. The expressions for electron wave propagation, reflection, and refraction are developed and shown to have the same functional form as in electromagnetics, if analogous definitions of electron wave phase and

  10. Estimation of radiation effects in the front-end electronics of an ILC electromagnetic calorimeter

    Microsoft Academic Search

    Valeria Bartsch; Martin Postranecky; C. Targett-Adams; M. Warren; M. Wing

    2008-01-01

    The front-end electronics of the electromagnetic calorimeter of an International Linear Collider detector are situated in a radiation environment. This requires the effect of the radiation on the performance of the electronics, specifically FPGAs, to be examined. In this paper we study the flux, particle spectra and deposited doses at the front-end electronics of the electromagnetic calorimeter of a detector

  11. Hot electron cooling by acoustic phonons in graphene.

    PubMed

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

    2012-08-01

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

  12. Ultrarelativistic Electron States in a General Background Electromagnetic Field

    NASA Astrophysics Data System (ADS)

    Di Piazza, A.

    2014-07-01

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

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

    PubMed

    Di Piazza, A

    2014-07-25

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

  14. 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.

  15. 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.

  16. Simulation on Generation of Electromagnetic Waves from Electron Beam: Application to Solar Type III Radio Bursts

    Microsoft Academic Search

    Daisuke Sugiyama; Jun-Ichi Sakai; Mitsuhiro Nambu

    2000-01-01

    Using a two-dimensional electromagnetic and relativistic particle-in-cell (2-D EM PIC) code, we show that electromagnetic waves are excited with near fundamental plasma frequency from relativistic electron beam instability. It is also shown that electromagnetic waves with almost second harmonics can be emitted after a little time delay.

  17. Superheterodyne amplification of electromagnetic waves in a system of two relativistic electron flows

    Microsoft Academic Search

    O. N. Bolonin; V. V. Kulish; V. P. Pugachev

    1988-01-01

    The dynamics of two relativistic electron beams in the presence of two transverse electromagnetic waves is examined for the case where one of the waves is an amplified (generated) electromagnetic wave (signal), such as an optical wave, and the other is a low-frequency electromagnetic wave or a periodically reversing magnetostatic field (wiggler). The problem is solved in the weak signal

  18. Application of thermoelectric cooling to electronic equipment: a review and analysis

    Microsoft Academic Search

    R. E. Simons; R. C. Chu

    2000-01-01

    This paper provides a review of thermoelectric cooling and its application to the cooling of electronic equipment. A background discussion of thermoelectric cooling is provided briefly citing early history, current developments, and the defining thermoelectric heat pumping equations. Several examples are provided of early IBM applications of thermoelectric cooling. An analysis to assess thermoelectric cooling enhancement in terms of increases

  19. 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

  20. Consumer electronics testing to fast-rise EMP (Electromagnetic Pulse) VEMPS (Vertical Electromagnetic Pulse Simulator) 2 development

    Microsoft Academic Search

    Vincent J. Ellis

    1989-01-01

    The Army has initiated a research and development effort for a new free-field, fast-rise Electromagnetic Pulse (EMP) simulator, the second-generation Vertical Electromagnetic Pulse Simulator (VEMPS 2). Because of the unique performance characteristics of VEMPS 2 and the technological changes in consumer electronics over the past 10 years, there is a need to evaluate the incidental effects of VEMPS-2-like simulated EMP

  1. 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.

  2. Electron-Ion Streaming Instabilities of AN Electromagnetically Accelerated Plasma.

    NASA Astrophysics Data System (ADS)

    Choueiri, Edgar Yazid

    This dissertation addresses the linear and nonlinear plasma physics associated with electron-ion streaming instabilities of an electromagnetically accelerated plasma. Specifically, the microinstabilities and related wave-particle transport in the working plasma of the Lorentz force accelerator (LFA) or magnetoplasmadynamic (MPD) thruster are investigated. The stability analysis required the derivation of a general dispersion tensor from kinetic theory for a magnetoactive plasma including the effects of a cross-field current, collisions, flowing plasma and arbitrary polarization. The inclusion of the last effect was necessitated by the finite beta (ratio of thermal to magnetic pressures) of such plasmas. While analytical solutions were only possible for some simplified situations the full electromagnetic problem including collisions required detailed numerical studies to reveal the nature, dependences and trends of the thresholds, frequencies, temporal and spatial growth rates, phase velocities and polarization of the unstable modes. The dominant instability was found to be the lower hybrid current-driven instability (LHCDI), which is the finite-beta generalization of the modified two-stream instability (MTSI). The effects of collisions, spatial evolution and plasma beta on the instability were studied parametrically. While the resulting dispersion relations describing the unstable waves in their linear growth stage were helpful to the design and interpretation of active wave injection experiments, the ultimate goal was an assessment of the importance of microturbulent transport namely the anomalous resistivity and heating rates engendered by the saturated unstable waves. For this purpose, finite -beta expressions for the anomalous resistivity and the anomalous heating rates of both ions and electrons were derived within the framework of a quasilinear weak turbulence formalism. Using the potential representation of the dielectric tensor it was possible to express the anomalous rates as an electrostatic contribution and a finite-beta (electromagnetic) correction. It was demonstrated through calculations in the region of parameter-space typical of the LFA plasma that the finite-beta correction can be significant and that the dominance of anomalous transport over classical dissipation is conditioned by large values of the electron Hall parameter. If the instabilities saturate by trapping the ions, the calculations show that significant enhancement to the local resistivity of the plasma can result in regions of low collisionality leading to the substantial thermalization, which would adversely impact the efficiency of plasma acceleration.

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

    SciTech Connect

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

    2008-04-01

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

  4. 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.

  5. Two-phase flow instability analysis for transient electronics cooling

    Microsoft Academic Search

    TieJun Zhang; Yoav Peles; John T. Wen; Michael K. Jensen

    2010-01-01

    Because of increasing power densities, refrigeration systems are being explored for two-phase cooling of ultra high power electronic components. This paper presents a framework for the transient analysis of pressure-drop refrigerant flow instabilities under both steady-state and transient imposed heat loads. Based on an analytical two-phase flow model, the system pressure and other effects on flow characteristics are quantitatively studied,

  6. Luminosity of the NICA Collider in working mode with using electron cooling system

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. B.; Meshkov, I. N.; Tuzikov, A. V.; Philippov, A. V.

    2014-09-01

    The paper investigates the problem of balance between the intrabeam scattering, electron cooling and radiative recombination processes in the NICA Collider working mode with using of electron cooling system. The reducing methods of radiative recombination influence due to electron cooling are discussed.

  7. Collective and single-electron interactions of electron beams with electromagnetic waves, and free-electron lasers

    Microsoft Academic Search

    A. Gover; A. Yariv

    1978-01-01

    The field of radiation emission from electron beams is reviewed with special reference to work related to free-electron lasers.\\u000a Different schemes of interaction in periodic structures, electromagnetic slow-wave structures, and in transverse confining\\u000a force are distinguished. Various effects and devices such as traveling wave amplifiers, Smith-Purcell radiators, Cerenkov\\u000a and bremsstrahlung-free electron lasers, cyclotron resonance masers, coherent bremsstrahlung and channeling radiation

  8. Electromagnetic field strength levels surrounding electronic article surveillance (EAS) systems.

    PubMed

    Harris, C; Boivin, W; Boyd, S; Coletta, J; Kerr, L; Kempa, K; Aronow, S

    2000-01-01

    Electronic article surveillance (EAS) is used in many applications throughout the world to prevent theft. EAS systems produce electromagnetic (EM) energy around exits to create an EM interrogation zone through which protected items must pass before leaving the establishment. Specially designed EAS tags are attached to these items and must either be deactivated or removed prior to passing through the EAS EM interrogation zone to prevent the alarm from sounding. Recent reports in the scientific literature have noted the possibility that EM energy transmitted by EAS systems may interfere with the proper operation of sensitive electronic medical devices. The Food and Drug Administration has the regulatory responsibility to ensure the safety and effectiveness of medical devices. Because of the possibility of electromagnetic interference (EMI) between EAS systems and electronic medical devices, in situ measurements of the electric and magnetic fields were made around various types of EAS systems. Field strength levels were measured around four types of EAS systems: audio frequency magnetic, pulsed magnetic resonant, radio frequency, and microwave. Field strengths from these EAS systems varied with magnetic fields as high as 1073.6 Am(-1) (in close proximity to the audio frequency magnetic EAS system towers), and electric fields up to 23.8 Vm(-1) (in close proximity to the microwave EAS system towers). Medical devices are only required to withstand 3 Vm(-1) by the International Electrotechnical Commission's current medical device standards. The modulation scheme of the signal transmitted by some types of EAS systems (especially the pulsed magnetic resonant) has been shown to be more likely to cause EMI with electronic medical devices. This study complements other work in the field by attaching specific characteristics to EAS transmitted EM energy. The quantitative data could be used to relate medical device EMI with specific field strength levels and signal waveforms. This is one of several efforts being made by the FDA, the electronic medical device industry and the EAS industry to mitigate the potential for EMI between EAS and medical devices. PMID:10608306

  9. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  11. 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.

  12. 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.

  13. Spin noise of localized electrons interacting with optically cooled nuclei

    NASA Astrophysics Data System (ADS)

    Smirnov, D. S.

    2015-05-01

    A theory of spin fluctuations of localized electrons interacting with an optically cooled nuclear spin bath has been developed. Since nuclear spin temperature may stay low enough for a macroscopically long time, the effect of dynamic nuclear polarization on electron spin dynamics can be directly revealed by means of spin noise spectroscopy. We have shown that in the case of weak fields/relatively high nuclear spin temperature, a small degree of nuclear spin polarization affects the electron spin fluctuations in the same way as an additional external magnetic field. By contrast, the high degree of nuclear polarization realized in relatively strong magnetic field and at low nuclear spin temperature leads to a suppression of hyperfine field fluctuations and to a dramatic narrowing of the precession-induced peak in the spin noise spectrum. The experimental possibilities of nuclear spin system investigation by means of spin noise spectroscopy are discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  15. 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

  16. 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 ...

  17. Diffusion-Cooled Tantalum Hot-Electron Bolometer Mixers

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

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

    Microsoft Academic Search

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

    1999-01-01

    A physical model is proposed for description of electron kinetics driven by a powerful electromagnetic pulse in the Earth's atmosphere. The model is based on a numerical solution to the Boltzmann kinetic equation for two groups of electrons. Slow electrons (with energies below a few keV) are described in a two-term approximation assuming a weak anisotropy of the electron distribution

  19. 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.

  20. Frenkel electron on an arbitrary electromagnetic background and magnetic Zitterbewegung

    NASA Astrophysics Data System (ADS)

    Deriglazov, Alexei A.; Pupasov-Maksimov, Andrey M.

    2014-08-01

    We present Lagrangian which implies both necessary constraints and dynamical equations for position and spin of relativistic spin one-half particle. The model is consistent for any value of magnetic moment ? and for arbitrary electromagnetic background. Our equations coincide with those of Frenkel in the approximation in which the latter have been obtained by Frenkel. Transition from approximate to exact equations yields two structural modifications of the theory. First, Frenkel condition on spin-tensor turns into the Pirani condition. Second, canonical momentum is no more proportional to velocity. Due to this, even when ?=1 (Frenkel case), the complete and approximate equations predict different behavior of a particle. The difference between momentum and velocity means extra contribution to spin-orbit interaction. To estimate the contribution, we found exact solution to complete equations for the case of uniform magnetic field. While Frenkel electron moves around the circle, our particle experiences magnetic Zitterbewegung, that is oscillates in the direction of magnetic field with amplitude of order of Compton wavelength for the fast particle. Besides, the particle has dipole electric moment.

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

    NASA Astrophysics Data System (ADS)

    Stagner, Colin Blake

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

  2. A New Principle for Electronic Cooling of Mesoscopic Systems

    NASA Astrophysics Data System (ADS)

    Rego, Luis G. C.

    2000-03-01

    In many semiconductor heterostructures the electrons behave like a low-dimensional system and develop new properties susceptible to control by an external parameter. Mesoscopic transport and optical properties have been studied extensively in this way, but low-dimensional thermal properties have to date received much less attention. In this work(Luis G.C. Rego and George Kirczenow, Appl. Phys. Lett. 75) (15), 2262 (99) we present the concepts of a new form of cooling of semiconductor mesoscopic samples which could be used in low temperature experiments. The cooling is the result of a quasi-static expansion of the electrons occupying the quasi-2D subbands of a quantum well (QW) or a multiple-quantum-well array, induced by an external electric field applied perpendicularly to the QW plane. Under ideal conditions the final temperature is half of the original and the dynamics of the process is universal and reversible. The feasibility of the process is investigated by self-consistent calculations at temperatures below 1K.

  3. 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.

  4. 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.

  5. Electron-ion collisions in strong electromagnetic fields: Quantum mechanical consideration

    NASA Astrophysics Data System (ADS)

    Serebryakov, D. A.; Balakin, A. A.; Fraiman, G. M.

    2014-09-01

    The quantum problem of electron-ion scattering in strong electromagnetic fields is studied by numerical simulations. The scattering characteristics are found to agree well with those earlier obtained in the classical limit. The simulations demonstrate the bunching of electrons during electron-ion collisions, which indicates the possibility of generation of attosecond pulses in strong fields.

  6. Electromagnetic Wave Propagation in an Annular Electron Beam With Ion Channel Guiding

    Microsoft Academic Search

    Farzin M. Aghamir; Hamid Almasi

    2011-01-01

    The dispersion characteristics of electrostatic and electromagnetic modes of an electron tube, with ion channel guid- ing, in a cylindrical waveguide are presented. The analysis takes into account a relativistic hollow electron beam guided by an ion channel. Dispersion relations are derived and solved numerically to study the waveguide, betatron, and space charge modes. The effect of the annular electron

  7. Consumer electronics testing to fast-rise EMP (Electromagnetic Pulse) VEMPS (Vertical Electromagnetic Pulse Simulator) 2 development

    NASA Astrophysics Data System (ADS)

    Ellis, Vincent J.

    1989-06-01

    The Army has initiated a research and development effort for a new free-field, fast-rise Electromagnetic Pulse (EMP) simulator, the second-generation Vertical Electromagnetic Pulse Simulator (VEMPS 2). Because of the unique performance characteristics of VEMPS 2 and the technological changes in consumer electronics over the past 10 years, there is a need to evaluate the incidental effects of VEMPS-2-like simulated EMP on modern consumer electronics. Although a similar evaluation of the effects of existing EMP simulators on consumer electronics was performed in 1978 the results obtained may not be directly applicable to the VEMPS 2 scenario and modern consumer electronics. One of the proposed site locations for the VEMPS 2 is the Woodbridge Research Facility (WRF), the location of the Army's lead laboratory for EMP research. The environment at WRF was used as a basis for developing the physical parameters associated with the test efforts described herein. Various types of consumer electronics identified through a survey of the Woodbridge, VA, community, were exposed to EMP environments similar to the predicted VEMPS 2 environments, and the results evaluated. The analysis indicates that the impact, if any, of VEMPS 2 operation on consumer electronics in the public areas outside WRF will be minimal.

  8. Influence of carrier density on the electronic cooling channels of bilayer graphene

    Microsoft Academic Search

    T. Limmer; A. J. Houtepen; A. Niggebaum; R. Tautz; E. da Como

    2011-01-01

    We study the electronic cooling dynamics in a single flake of bilayer graphene by femtosecond transient absorption probing the photon-energy range 0.25-1.3 eV. From the transients, we extract the carrier cooling curves for different initial temperatures and densities of the photoexcited electrons and holes. Two regimes of carrier cooling, dominated by optical and acoustic phonons emission, are clearly identified. For

  9. The design and testing of the super fiber heat pipes for electronics cooling applications

    Microsoft Academic Search

    Ioan Sauciuc; Masataka Mochizuki; Kouichi Mashiko; Yuji Saito; Thang Nguyen

    2000-01-01

    Cooling of electronics is one of the major fields of application for heat pipes (3-9-mm outside diameter) with a worldwide demand exceeding one million per month. The high heat fluxes associated with electronics cooling require heat pipes with high maximum heat transfer at any inclination, and therefore improved wick structures are needed. In particular, the operation at top heat mode

  10. 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.

  11. Support vector machine in application of modeling of electromagnetic pulse field coupling on electronic devices

    Microsoft Academic Search

    Yang Nan; Wei Ming; Chen Xiang

    2010-01-01

    The vulnerability of electronic devices to EMP (Electromagnetic Pulse) has been increased, and the assessment of EMP effects is the key to solving such problems. Furthermore, the simulation of EMP effects on electronic devices is an important means of assessing their effects. Targeting the universally existing complex computing process problems in mechanism modeling algorithm ubiquity, it have been researched that

  12. Numerical Study of Electromagnetic ETG Turbulence: -dependence of Electron Heat Transport

    E-print Network

    , which describes the evolution of three macroscopic fields: the electrostatic potential, the vectorNumerical Study of Electromagnetic ETG Turbulence: -dependence of Electron Heat Transport B. Labit potential and the electron pressure. There is some evidence from experiments on Tore Supra tokamak

  13. 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.

  14. INTERACTION OF ELECTROMAGNETIC WAVE AND PLASMA SLAB WITH PARTIALLY LINEAR AND SINUSOIDAL ELECTRON DENSITY PROFILE

    Microsoft Academic Search

    S. Gurel; Emrah Oncu

    2009-01-01

    Interaction of an electromagnetic wave and an inhomoge- neous plasma slab with electron distribution in the form of partially linear and sinusoidal proflles is analysed to determine new re?ection, absorbtion and transmission characteristics. Broadband and tunable absorbtion performance of the plasma layer accompanied with narrow- band re?ection characteristic is presented as the function of electron density proflle parameters and external

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

    SciTech Connect

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

    2007-08-01

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

  16. Medium energy electron cooling R and D at Fermilab -- Context and status

    SciTech Connect

    MacLachlan, J.A.

    1996-05-01

    Electron cooling at the proposed Recycler 8 GeV storage ring has been identified as a key element in exploiting the capacity of the Fermilab Main Injector for an additional factor of ten in Tevatron luminosity above the goal for the next collider run, ultimately to > 10{sup 33} cm{sup {minus}2}s{sup {minus}1}. The most basic requirement for increased luminosity is a large stack of antiprotons cooled to emittance comparable to that of the proton beam. Although electron cooling is inferior to the stochastic technique for cooling large emittance beams, its rate is practically independent of the antiproton intensity. For cooling intense beams of low or moderate emittance, electron cooling excels. The realization of electron cooling for 8 GeV antiprotons requires major extension of existing practice in electron energy and length of the cooling interaction region. It will require 4.3 MeV dc electron beam maintaining high quality and precise collinearity with the antiprotons over a 66 m straight section. The initial goal of the R and D project is 200 mA electron current in about three years; the plan is to reach 2 A over the following three years.

  17. An analog of the Feynman-Kac formula for Dirac's electron in electromagnetic field and the correspondence principle

    E-print Network

    A. A. Beilinson

    2015-06-12

    The article describes a relation between the fundamental solutions of Dirac's equations for free electron and electron in given electromagnetic field viewed as functionals on bump functions. We explain how classical relativistic mechanics of a charged particle in given electromagnetic field arises from quantum mechanics of Dirac's electron in that field.

  18. Spray cooling characteristics of nanofluids for electronic power devices

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  19. Spray cooling characteristics of nanofluids for electronic power devices.

    PubMed

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

    2015-01-01

    The performance of a single spray for electronic power devices using deionized (DI) water and pure silver (Ag) particles as well as multi-walled carbon nanotube (MCNT) particles, respectively, is studied herein. The tests are performed with a flat horizontal heated surface using a nozzle diameter of 0.5 mm with a definite nozzle-to-target surface distance of 25 mm. The effects of nanoparticle volume fraction and mass flow rate of the liquid on the surface heat flux, including critical heat flux (CHF), are explored. Both steady state and transient data are collected for the two-phase heat transfer coefficient, boiling curve/ cooling history, and the corresponding CHF. The heat transfer removal rate can reach up to 274 W/cm(2) with the corresponding CHF enhancement ratio of 2.4 for the Ag/water nanofluids present at a volume fraction of 0.0075% with a low mass flux of 11.9?×?10(-4) kg/cm(2)s. PMID:25852429

  20. Influence of carrier density on the electronic cooling channels of bilayer graphene

    NASA Astrophysics Data System (ADS)

    Limmer, T.; Houtepen, A. J.; Niggebaum, A.; Tautz, R.; Da Como, E.

    2011-09-01

    We study the electronic cooling dynamics in a single flake of bilayer graphene by femtosecond transient absorption probing the photon-energy range 0.25-1.3 eV. From the transients, we extract the carrier cooling curves for different initial temperatures and densities of the photoexcited electrons and holes. Two regimes of carrier cooling, dominated by optical and acoustic phonons emission, are clearly identified. For increasing carrier density, the crossover between the two regimes occurs at larger carrier temperatures, since cooling via optical phonons experiences a bottleneck. Acoustic phonons, which are less sensitive to saturation, show an increasing contribution at high density.

  1. 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.

  2. Side-scattering of an ordinary electromagnetic wave by electron-acoustic oscillations

    Microsoft Academic Search

    R. P. Sharma; M. Y. Yu

    1982-01-01

    The paper investigates a parametric instability involving electron-acoustic waves, the scattering of an ordinary electromagnetic wave into a circularly polarized wave by electron-acoustic oscillations. The case in which an ordinary wave propagates exactly perpendicular to the external field is considered. The circularly polarized wave propagates along the magnetic field, and the electron-acoustic wave propagates at an angle to the external

  3. New method for efficient HIRF attenuation in aircraft cooling ducts

    Microsoft Academic Search

    Simon Rea; David Linton; E. Orr; Jonathan McConnell

    2003-01-01

    Intensity Radiated Fields (HIRF) to be present close to electronic systems. This threat is made more serious by the fact that some electronic systems need to be cooled via air ducts on the side of the aircraft, creating leakage points for electromagnetic radiation. One such electronic system is the Full Authority Digital Engine Controller (FADEC). The FADEC is cooled from

  4. Squeezing of electromagnetic field in a cavity by electrons in Trojan states

    NASA Astrophysics Data System (ADS)

    Kocha?ski, Piotr; Bialynicka-Birula, Zofia; Bialynicki-Birula, Iwo

    2001-01-01

    The notion of the Trojan state of a Rydberg electron, introduced by I. Bialynicki-Birula, M. Kali?ski, and J. H. Eberly [Phys. Rev. Lett. 73, 1777 (1994)] is extended to the case of an electromagnetic field quantized in a cavity. The shape of the electronic wave packet describing the Trojan state is practically the same as in the previously studied externally driven system. The fluctuations of the quantized electromagnetic field around its classical value exhibit strong squeezing. The emergence of Trojan states in the cylindrically symmetrical system is attributed to spontaneous symmetry breaking.

  5. 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.

  6. 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.

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

    SciTech Connect

    Tur, A.; Fruit, G.; Louarn, P. [Institut de Recherche en Astrophysique et Planétologie (IRAP), CNRS UMR5277/Université Paul Sabatier, Toulouse (France)] [Institut de Recherche en Astrophysique et Planétologie (IRAP), CNRS UMR5277/Université 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 instability–electromagnetic electron-bounce instability–may explain fast and global scale destabilization of current sheets as required to describe substorm phenomena.

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

    SciTech Connect

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

    2007-01-01

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

  9. 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.

  10. Electron trajectory and growth rate in a two-stream electromagnetically pumped free electron laser and axial guide field

    SciTech Connect

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

    2008-09-15

    The effects of two-stream on electromagnetic wiggler free electron lasers (TSEMWFEL) with an axial guiding magnetic field are studied. An analysis of the two-stream steady-state electron trajectories is given by solving the equation of motion in the axial guiding magnetic field and the electromagnetic wiggler. Numerical calculations are made to illustrate the effects of the dual electron beam on the trajectories. The dispersion relation is derived employing linear fluid theory. The characteristics of the dispersion relation are analyzed numerically. The result shows that the growth rate is considerably enhanced in comparison with single-stream. The maximum growth rate is studied numerically as a function of axial guiding magnetic field for multiple electron trajectories. It is shown that the maximum growth rate of TSEMWFEL increases and decreases with respect to the axial guiding field for different trajectories.

  11. A robust platform cooled by superconducting electronic refrigerators

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  12. Effect of the electromagnetic environment on the single electron transistor

    Microsoft Academic Search

    Gert-Ludwig Ingold; Petra Wyrowski; Hermann Grabert

    1991-01-01

    The influence of envirommental impedances on tunneling rates in a single electron transistor circuit is investigated. Effects of the finite gate capacitance and of stray capacitances at the tunnel junctions are considered. For the case of a low impedance environment the electron tunneling rates reduce to the so-called global rule rate while for a high impedance environment a modification of

  13. The non-linear field theory III: Geometrical illustration of the electromagnetic representation of Dirac's electron theory

    E-print Network

    Alexander G. Kyriakos

    2004-07-09

    The present paper is the continuity of the previous papers "Non-linear field theory" I and II. Here on the basis of the electromagnetic representation of Dirac's electron theory we consider the geometrical distribution of the electromagnetic fields of the electron-positron. This gives the posibility to obtain the explanation and solution of many fundamental problems of the QED.

  14. Hot Electron Cooling by Acoustic Phonons in Graphene A. C. Betz,1

    E-print Network

    Plaçais, Bernard

    Hot Electron Cooling by Acoustic Phonons in Graphene A. C. Betz,1 F. Vialla,1 D. Brunel,1 C. Voisin accurate values of the electron-acoustic phonon coupling constant Æ in monolayer graphene. Our measurements on the interaction between electrons and acoustic phonons in monolayer graphene. To this end, we have investigated

  15. 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.

  16. 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.

  17. Interplay of electrostatic and electromagnetic instabilities for relativistic electron beams in a plasma

    Microsoft Academic Search

    D. D. Ryutov

    2008-01-01

    The physics of relativistic electron particle beams propagating through the plasma is of a significant interest for laboratory astrophysics, fast ignition, and Z-pinch research. Most attention has been directed towards the analysis of electromagnetic filamentation instabilities. On the other hand, there exists a broad class of very powerful electrostatic instabilities, e.g., the Buneman instability. The author considers in a unified

  18. Coupling of ESD-generated (electrostatic discharges) EMP (electromagnetic pulse) to electronics

    NASA Astrophysics Data System (ADS)

    Boverie, Bill

    Electrostatic discharges (ESD) can generate an electromagnetic pulse (EMP) which can couple into electronic circuits. Analytical and experimental models of this coupling demonstrate that, under some circumstances, the energy coupled to an integrated circuit on a printed circuit board is proportional to the product of the peak E-field and the derivative of the E-field.

  19. Generation of electromagnetic waves in the electron-positron plasma in the vicinity of a pulsar

    Microsoft Academic Search

    M. A. Akhalkatsi; G. Z. Machabeli

    2000-01-01

    The problem of the efficiency of the ion-synchrotron maser proposed by Hoshino and Arons is analyzed in a linear approximation. A hot, relativistic, electron-positron plasma penetrated by a relativistic ion beam is considered. At the front of the magnetosonic shock wave an electromagnetic wave is generated, which should be damped on positrons of the plasma. This should, in turn, result

  20. Spectrum and polarization of electrons in neutron beta-decay in an electromagnetic wave field

    Microsoft Academic Search

    O. F. Dorofeev; A. E. Lobanov; O. S. Pavlova; V. N. Rodionov

    1987-01-01

    A study is made on a polarized neutron undergoing beta-decay induced by an intense electromagnetic wave. The angular distribution of electrons in the decay is obtained and their polarization is studied. A comparison is made with the decay of a moving neutron.

  1. Almost-parallel electromagnetic wave propagation at frequencies near the electron plasma frequency

    Microsoft Academic Search

    S. S. Sazhin

    1988-01-01

    An approximate dispersion equation for almost-parallel electromagnetic wave propagation in a weakly relativistic plasma at frequencies near the electron plasma frequency is derived and investigated both analytically and numerically. It is pointed out that the cold plasma approximation cannot be applied to the analysis of these waves in any realistic (e.g., magnetospheric or astrophysical) plasma.

  2. 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 Bâ 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

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

    SciTech Connect

    Ben-Zvi, Ilan [Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2006-03-20

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

  4. Foil cooling for rep-rated electron beam pumped KrF lasers

    NASA Astrophysics Data System (ADS)

    Giuliani, J. L.; Hegeler, F.; Sethian, J. D.; Wolford, M. F.; Myers, M. C.; Abdel-Khalik, S.; Sadowski, D.; Schoonover, K.; Novak, V.

    2006-06-01

    In rep-rated electron beam pumped lasers the foil separating the vacuum diode from the laser gas is subject to repeated heating due to partial beam stopping. Three cooling methods are examined for the Electra KrF laser at the Naval Research Laboratory (NRL). Foil temperature measurements for convective cooling by the recirculating laser gas and by spray mist cooling are reported, along with estimates for thermal conductive foil cooling to the hibachi ribs. Issues on the application of each of these approaches to laser drivers in a fusion power plant are noted. Work supported by DOE/NNSA.

  5. 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.

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

    SciTech Connect

    Green, Michael A.

    2003-07-09

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

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

    NASA Technical Reports Server (NTRS)

    Temerin, M.; Mcfadden, J.; Boehm, M.; Carlson, C. W.; Lotko, W.

    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 on auroral arc field lines. A model of the electromagnetic ion cyclotron wave shows that the parallel phase velocity of the wave increase as the wave propagates toward the ionosphere. A test particle calculation shows that ionospheric electrons trapped or reflected by the wave are accelerated to energies of several keV and that their flux is modulated at the wave frequency. The relative amplitudes of the model wave electric fields are consistent with the observations of small-scale low-frequency ionospheric and magnetospheric electric fields near auroral arcs of approximately 10 mV/m and 100 mV/m, respectively. The large-amplitude ion cyclotron waves also produce a ponderomotive force and a self-consistent ambipolar electric field. Energy considerations show that the downward energy flux in the electromagnetic ion cyclotron wave can be several percent of the total downward auroral electron energy flux.

  8. Electronic Spectra of the Jet-Cooled Acetaminophen

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  9. Electronic cooling technology with use of turbulent impinging jets

    Microsoft Academic Search

    R. S. Amano

    2000-01-01

    An investigation on cooling of the solid surface was performed by studying the behaviors of impinging jets onto a fixed flat plate. The flow and local heat transfer coefficient distributions on a plate with a constant heat source were numerically investigated with a normally impinging axisymmetric jet. Numerical predictions of the mean velocities across the jet were. Made with several

  10. Investigation of the heat pipe arrays for convective electronic cooling 

    E-print Network

    Howard, Alicia Ann Harris

    1993-01-01

    A combined experimental and analytical investigation was conducted to evaluate a heat pipe convective cooling device consisting of sixteen small copper/water heat pipes mounted vertically in a 4x4 array 25.4 mm square. The analytical portion...

  11. 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.

  12. 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).

  13. An electromagnetic/electrostatic dual cathode system for electron beam instruments

    NASA Technical Reports Server (NTRS)

    Bradley, J. G.; Conley, J. M.; Wittry, D. B.; Albee, A. L.

    1986-01-01

    A method of providing cathode redundancy which consists of two fixed cathodes and uses electromagnetic and/or electrostatic fields to direct the electron beam to the electron optical axis is presented, with application to the cathode system of the Scanning Electron Microscope and Particle Analyzer proposed for NASA's Mariner Mark II Comet Rendezvous/Asteroid Flyby projected for the 1990s. The symmetric double deflection system chosen has the optical property that the image of the effective electron source is formed above the magnet assembly near the apparent position of the effective source, and it makes the transverse positions of the electron sources independent of the electron beam energy. Good performance of the system is found, with the sample imaging resolution being the same as for the single-axis cathode.

  14. Piezoelectric ceramic bimorph coupled to thin metal plate as cooling fan for electronic devices

    Microsoft Academic Search

    Ju Hyun Yoo; Jae Il Hong; Wenwn Cao

    2000-01-01

    Several types of piezoelectric fans for cooling electronic devices were constructed and tested at 60 Hz, 110 V and 220 V, respectively. The aim of the work is to investigate the possibility of replacing the rotary type of fan in some noise-sensitive electronic devices. Different vibrating metal plates were tested and analyzed theoretically. It is found that the resonant frequency

  15. Fabrication of a diffusion cooled superconducting hot electron bolometer for THz mixing applications

    Microsoft Academic Search

    Bruce Bumble; Henry G. LeDuc

    1997-01-01

    Recent interest in bolometers for heterodyne mixing applications has prompted development of microbridges which are small enough to allow electron diffusion to dominate over electron-phonon interaction as a cooling mechanism. Prior results at 533 GHz have demonstrated several GHz intermediate frequency (IF) bandwidth. Here we describe our processing method in which the bolometer element is a 10 nm thin film

  16. Nonanalyticity of the Electron Distribution Function and Nonlinear Electromagnetic Waves in Semiconductors

    NASA Astrophysics Data System (ADS)

    Rozhkov, Sergei S.

    2000-03-01

    Nonanalyticity of the Electron Distribution Function and Nonlinear Electromagnetic Waves in Semiconductors S.S.Rozhkov Institute of Physics, Ukrainian Academy of Sciences, Kyiv, Ukraine It is shown that propagation of electromagnetic waves in a plasma is nonlinear if the charge carrier distribution function has fractures or, more exactly, nonanalyticies. This result is valid for any plasma. In the case under consideration the nature of the nonanalyticities is connected with spontaneous optical-phonon emission by the nonequilibrium electrons of a semiconductor. The standard wave equation for the electromagnetic field E in a plasma implies that the formula dJ/dt = (?o ?_p^2/4?)E for the current density J takes place (eo is the static dielectric constant and wp is the plasma frequency). If the distribution function f(p) is nonanalytical on some set of points of momentum space, then the ordinary formula connecting J and E is violated, and the wave equation becomes nonlinear. In the high-frequency limit we find the function f(p) and derive the wave equation for E in a semiconductor placed in parallel constant electric and quantizing magnetic fields. In such a situation the stationary electron distribution function acquires sharply expressed fractures as a result of runaway of the electrons and spontaneous optical-phonon emission hindering the runaway. Creation and dynamics of dark envelope solitons for the field E are discussed footnote S.S.Rozhkov, JETP 71, 1135 (1990).

  17. 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.

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

    SciTech Connect

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

    2011-03-01

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

  19. Gas-assisted evaporative cooling of high density electronic modules

    Microsoft Academic Search

    Avram Bar-Cohen; Greg Sherwood; Marc Hodes; Gary Solbreken

    1995-01-01

    Gas-assisted evaporative cooling (GAEC), its advantages in thermal packaging of microelectronics, and its implementation in a prototype high-performance computer module, are described. Attention is then turned to theoretical considerations in the flow of gas-liquid-vapor mixtures in narrow, parallel plate channels, and to the design and operation of an appropriate experimental apparatus. Next, experimental results for the wall temperature, heat-transfer coefficients,

  20. 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.

  1. 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

  2. Control of electromagnetic interference from arc and electron beam welding by controlling the physical parameters in arc or electron beam theoretical model

    Microsoft Academic Search

    T. R. Anderson

    2000-01-01

    Arc and electron beam welding can cause electromagnetic interference in nearby electronic equipment. The radiated power of a plasma arc or electron beam from welding is derived in this research from charge continuity and plasma momentum equations and treating the arcing plasma and electron beam as a radiating dipole. The net radiated power from the arc is calculated as a

  3. Two-Phase Cooling of Targets and Electronics for Particle Physics Experiments

    E-print Network

    Thome, J R; Park, J E

    2009-01-01

    An overview of the LTCM lab’s decade of experience with two-phase cooling research for computer chips and power electronics will be described with its possible beneficial application to high-energy physics experiments. Flow boiling in multi-microchannel cooling elements in silicon (or aluminium) have the potential to provide high cooling rates (up to as high as 350 W/cm2), stable and uniform temperatures of targets and electronics, and lightweight construction while also minimizing the fluid inventory. An overview of two-phase flow and boiling research in single microchannels and multi-microchannel test elements will be presented together with video images of these flows. The objective is to stimulate discussion on the use of two-phase cooling in these demanding applications, including the possible use of CO2.

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

    NASA Astrophysics Data System (ADS)

    Yoffe, Samuel R.; Kravets, Yevgen; Noble, Adam; Jaroszynski, Dino A.

    2015-05-01

    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.

  5. Transverse Feedback for Electron-Cooled DC-Beam at COSY

    SciTech Connect

    Kamerdzhiev, V.; Dietrich, J. [Forschungszentrum Juelich GmbH, Institut fuer Kernphysik (Germany)

    2004-11-10

    At the cooler synchrotron COSY, high beam quality is achieved by means of beam cooling. In the case of intense electron-cooled beams, fast particle losses due to transverse coherent beam oscillations are regularly observed. To damp the instabilities a transverse feedback system was installed and successfully commissioned. Commissioning of the feedback system resulted in a significant increase of the e-cooled beam intensity by single injection and when cooling and stacking of repeated injections is applied. External experiments profit from the small diameter beams and the reduced halo. A transverse damping system utilizing a pick-up, signal processing electronics, power amplifiers, and a stripline deflector is introduced. Beam current and Schottky spectra measurements with the vertical feedback system turned on and off are presented.

  6. Current-driven turbulence caused by the emission of fast electrons in an inhomogeneous plasma in an intense electromagnetic field

    Microsoft Academic Search

    D. M. Karfidov; N. A. Lukina; K. F. Sergeichev

    1981-01-01

    It has been shown experimentally that the emission of currents of fast electrons from a critical sheath in a plasma under the influence of an intense electromagnetic field occurs against the background of a current-driven turbulence of the plasma. This turbulence may be responsible, along with a modulational instability, for the transfer of energy from the electromagnetic field to fast

  7. Laboratory for Electromagnetic Fields and Microwave Electronics, ETH Zurich, Switzerland Dept. of Electrical and Computer Engineering, University of Victoria, Canada

    E-print Network

    Bornemann, Jens

    thin wires, a modified induced electromagnetic force technique, e.g. [5]. For the far-field analysis* Laboratory for Electromagnetic Fields and Microwave Electronics, ETH Zurich, Switzerland + Dept are coherently combined before detection and do not suffer from quantization errors in individual elements

  8. Generation of electromagnetic waves in the electron-positron plasma in the vicinity of a pulsar

    Microsoft Academic Search

    M. A. Akhalkatsi; G. Z. Machabeli

    2000-01-01

    The problem of the efficiency of the ion-synchrotron maser proposed by Hoshino and Arons is analyzed in a linear approximation.\\u000a A hot, relativistic, electron-positron plasma penetrated by a relativistic ion beam is considered. At the front of the magnetosonic\\u000a shock wave an electromagnetic wave is generated, which should be damped on positrons of the plasma. This should, in turn,\\u000a result

  9. Harmonic generation in scattering of electromagnetic waves by anharmonically bound electrons

    Microsoft Academic Search

    R. Goyal; H. Prakash

    1969-01-01

    Summary  Scattering of electromagnetic waves by anharmonically bound electrons is studied. It is found that, if, for distances from\\u000a the centre of attraction of the order of atomic radii, the terms representing anharmonic binding are assumed to become as\\u000a much important as the harmonic binding term, the contribution of anharmonicity to the nonlinear effects is ? 106 times that of other

  10. Short-period equipotential-bus electromagnetic undulator for a far infrared free-electron laser

    Microsoft Academic Search

    Young Uk Jeong; Byung Cheol Lee; Sun Kook Kim; Sung Oh Cho; Byung Heon Cha; Jongmin Lee; Pavel D. Vobly; Yuri M. Kolokolnikov; Stepan F. Mihaylov; Gennady N. Kulipanov

    1998-01-01

    An equipotential-bus electromagnetic undulator has been developed for a far infrared compact free-electron laser. It has 2m length, 5.6mm gap, and 12.5mm period. The field distribution along the undulator is formed by 2.25mm thick poles of low-carbon steel with 4mm thick Nd–Fe–B permanent magnets between them. The amplitude of the magnetic field is up to 6kG. The variation of current

  11. 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.

  12. Heat transfer enhancement using Al 2O 3–water nanofluid for an electronic liquid cooling system

    Microsoft Academic Search

    Cong Tam Nguyen; Gilles Roy; Christian Gauthier; Nicolas Galanis

    2007-01-01

    We have experimentally investigated the behaviour and heat transfer enhancement of a particular nanofluid, Al2O3 nanoparticle–water mixture, flowing inside a closed system that is destined for cooling of microprocessors or other electronic components. Experimental data, obtained for turbulent flow regime, have clearly shown that the inclusion of nanoparticles into distilled water has produced a considerable enhancement of the cooling block

  13. Electromagnetic fluctuations due to electron shear flow instabilities in collisionless magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Jain, Neeraj; Buechner, Joerg

    2015-04-01

    In Collision-less magnetic reconnection electron scale current sheets (thickness ~ de = c/?pe ) develop embedded inside an ion scale current sheet (thickness ~ di = c/?pi).These electron current sheets (ECS) are susceptible to electron shear flow instabilities (ESFI). The ESFI can grow both as tearing, which forms electron scale magnetic islands, and non-tearing modes which may cause filamentation of the ECS. Usually experiments do not capture the growth phase of an instability. However they do record electromagnetic fluctuations, such as in VINETA-II and Magnetic Reconnection Experiment (MRX), possibly resulting from the non-linearly saturated state of the instabilities. We study electromagnetic fluctuations in non-linearly saturated state of ESFIs. An electron-magnetohydrodynamic model is used for the 2-D and 3-D nonlinear simulations of ESFI. The 2-D simulations are carried out in two mutually perpendicular planes: (1) plane perpendicular to the equilibrium electron current and (2) plane containing the directions of equilibrium current and shear in it. Such 2-D simulations will help us isolating the fluctuations caused by tearing and non-tearing modes. The effect of current sheet thickness and guide field will be investigated.

  14. 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.

  15. PCB-Integrated Heat Exchanger for Cooling Electronics Using Microchannels Fabricated With the Direct-Write Method

    Microsoft Academic Search

    Ramzi Bey Oueslati; Daniel Therriault; Sylvain Martel

    2008-01-01

    The electronic industry has a growing need for efficient heat dissipation mechanisms such as micro heat exchanger systems. This active cooling approach requires the integration of microfluidic components near the main heat sources of the electronic devices. Despite the investigation of several micro-cooling configurations, their commercial utilization by the electronic industry is rather limited due to complex fabrication and integration

  16. Feedback Cooling of a One-Electron Oscillator B. D'Urso, B. Odom, and G. Gabrielse

    E-print Network

    Gabrielse, Gerald

    Feedback Cooling of a One-Electron Oscillator B. D'Urso, B. Odom, and G. Gabrielse Department January 2003) A one-electron oscillator is cooled from 5.2 K to 850 mK using electronic feedback. Novel) is observed to be a fluctuation-dissipation invariant, independent of feedback gain, as predicted

  17. Coupling of electrons to the electromagnetic field in a localized basis

    E-print Network

    Allen, Roland E.

    2008-01-01

    Coupling of electrons to the electromagnetic field in a localized basis Roland E. Allen* Department of Physics, Texas A&M University, College Station, Texas 77843, USA #1;Received 3 June 2008; revised manuscript received 26 July 2008; published...? simulations for treating problems where standard Ehrenfest simulations will fail. DOI: 10.1103/PhysRevB.78.064305 PACS number#1;s#2;: 78.20.Bh, 71.15.Pd It is now possible to perform first-principles simulations of the coupled dynamics of electrons...

  18. Coupling of electrons to the electromagnetic field in a localized basis 

    E-print Network

    Allen, Roland E.

    2008-01-01

    Coupling of electrons to the electromagnetic field in a localized basis Roland E. Allen* Department of Physics, Texas A&M University, College Station, Texas 77843, USA #1;Received 3 June 2008; revised manuscript received 26 July 2008; published...? simulations for treating problems where standard Ehrenfest simulations will fail. DOI: 10.1103/PhysRevB.78.064305 PACS number#1;s#2;: 78.20.Bh, 71.15.Pd It is now possible to perform first-principles simulations of the coupled dynamics of electrons...

  19. 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.

  20. On the heat transfer enhancement based on micro-scale air impinging jets with microstructure heat sink in electronics cooling

    Microsoft Academic Search

    Jing-yu Fan; Yan Zhang; Johan Liu

    2006-01-01

    A conceptual heat transfer enhancement scheme in electronic cooling is analyzed on the basis of micro-scale impinging jet array with microstructure heat sink. The cooling performance of the micro impinging jet array is discussed and compared with that of conventional large-scale jet impingement cooling, and the pressure drop due to the induced crossflow is a vital factor for the former.

  1. Study and realization of a high power density electronics device cooling loop using a liquid metal coolant

    Microsoft Academic Search

    Mansour Tawk; Yvan Avenas; Afef Kedous-Lebouc; Mickael Petit

    2011-01-01

    Thermal management became the limiting factor in the development of high power electronic devices and new methods of cooling are required. Due to the low thermal conductivity of classical liquids (water, alcohols, dielectric fluids…), in many cases, the standard liquid cooling techniques cannot achieve the required cooling performances. Therefore the use of liquid gallium alloys whose thermal conductivity (approx. 28W\\/m\\/K)

  2. Collisional Cooling of Pure Electron Plasmas W. Bertsche

    E-print Network

    Fajans, Joel

    into the vacuum chamber via a leak valve and monitored with an ion gauge and residual gas analyzer. For mea thermal energy. Motivated by an examination of spectroscopic data, calculations of electron-CO2 scattering thermal equilibrium giving T T. The plasma temper- ature with no buffer gas (base pressure 5·10-10 torrto

  3. 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.

  4. 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

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

    SciTech Connect

    Chen, S. H.; Tai, L. C.; Liu, Y. L. [Department of Physics, National Central University, Jhongli 32001, Taiwan (China); Ang, L. K. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Koh, W. S. [Institute of High Performance Computing, A-STAR, Singapore 138632 (Singapore)

    2011-02-15

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

  6. Enhancement in Cooling of Electronic Components by Nanofluids

    NASA Astrophysics Data System (ADS)

    Khatak, Pankaj; Jakhar, Rahul; Kumar, Mahesh

    2015-04-01

    In this study, heat transfer during spray cooling was studied experimentally using water and ZnO nanofluid. Various experiments were performed using a spray nozzle impinging fluid normal to the flat end of a copper heated surface (copper cylinder 20 mm diameter). The heat flux and surface temperature have been calculated by measuring temperature gradients along the target length under steady state conditions. In this experimental study, water flow rate was varied from 15 to 25 ml/min. In the same test conditions to compare water results with nanofluids, ZnO nanofluid was sprayed at a flow rate of 20 ml/min. It can be observed that a surface temperature 74.1 °C was obtained with maximum heat flux of 102.40 W/cm2 under the test condition for heater power 140 W and a water flow rate 25 ml/min. The use of ZnO nanofluid as a coolant is observed to increase the heat flux by about 20.2 % and decrease surface temperature of the test specimen by about 15 % at 180 W heat input and flow rate of 20 ml/min. The uncertainty in heat flux is observed to vary from 8.63 to 10.93 %.

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

    PubMed

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

    1999-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1999-12-01

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

  9. Electron-gas cooling studied by measurements of noise temperature

    Microsoft Academic Search

    S. Asmontas; J. Liberis; L. Subacius; G. Valusis

    1992-01-01

    Data from a detailed investigation of the variation of longitudinal and transverse noise temperature with changing electric field strength in compensated n-InSb(Cr) are presented. It is found that longitudinal noise temperature decreases with the diminishing electron concentration, n, and it does not exceed the lattice temperature TO, when n<2*1011 cm-3 at electric fields E<100 V cm-1. It has been explained

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

    SciTech Connect

    Not Available

    2011-07-01

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

  11. DESIGN OF A 6 MeV ELECTRON COOLING SYSTEM FOR THE SSC MEDIUM ENERGY BOOSTER

    Microsoft Academic Search

    Dan R. Anderson; Mark S. Ball; David Caussyn; Michael J. Ellison; Tim J. P. Ellison; Dennis L. Friesel; Brett Hamilton; S. Y. Lee; Sergei Nagaitsev; Peter Schwandt; Jim Adney; Jim Ferry; Mark Sundquist; Dag Reistad; Miro Sedlacek; Gulomb Logarithm A

    A 6 MeV 2 A electron cooling system is being designed for the SSC Medium Energy Booster (MEB). This system will decrease the beam emittance by at least a factor of two in 25 to 60 s, consequently increasing the initial SSC luminosity by the same factor. Alternately, the required number of p,articles per bunch (and therefore synchrotron radiation and

  12. Boiling Heat Transfer Enhancement Using Micro-Machined Porous Channels for Electronics Cooling

    Microsoft Academic Search

    Navas Khan; K. C. Toh; D. Pinjala

    2008-01-01

    Boiling heat transfer enhancement for a passive electronics cooling design is presented in this paper. A novel pool boiling enhancement technique is developed and characterized. A combination of surface modification by metallic coating and micro-machined porous channels attached to the modified surface is tested and reported. An experimental rig is set up using a standard BGA package with 12 mm

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  14. A room temperature, or moderately cooled, fast THz semiconductor hot electron bolometer

    Microsoft Academic Search

    V. Dobrovolsky; F. Sizov

    2007-01-01

    A fast THz bolometer is proposed in which, unlike the conventional thermal one, electromagnetic radiation heats only electrons in a narrow gap semiconductor without its lattice inertial heating. Under determined conditions, this heating changes generation-recombination processes that cause the carrier number to decrease and the semiconductor resistance to rise. The Hg0.8Cd0.2Te detector noise equivalent power in the range of 77-300

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

    SciTech Connect

    Shiryaev, O. B. [Department of Coherent and Nonlinear Optics, General Physics Institute of the Russian Academy of Science, 38 Vavilov Street, Box 119991, Moscow (Russian Federation)

    2008-01-15

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

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

    SciTech Connect

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

  17. 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.

  18. Estimation of radiation eects in the front-end electronics of the Electromagnetic Calorimeter using physics events

    Microsoft Academic Search

    V. Bartsch; M. Postranecky; C. Targett-Adams; M. Warren; M. Wing

    2007-01-01

    The front-end electronics of the electromagnetic calorimeter of an ILC detector are situated in a radiation environment. Therefore it needs to be checked how the ra- diation will aect the performance of the electronics. In this paper, physics events and hadron events originating from the machine background have been simulated and radiation eects within the volumes in which the front-end

  19. Simulation and Modeling Techniques for Signal Integrity and Electromagnetic Interference on High Frequency Electronic Systems.

    E-print Network

    Daniel, Luca

    challenging magnetic field inductive coupling, and even full-wave propagating electromagnetic field couplings parameterized modeling technique. The new generation of fast electromagnetic analysis programs, basedSimulation and Modeling Techniques for Signal Integrity and Electromagnetic Interference on High

  20. Negligible electromagnetic interaction between medical electronic equipment and 2.4 GHz band wireless LAN.

    PubMed

    Hanada, Eisuke; Hoshino, Yasushi; Oyama, Hiroshi; Watanabe, Yoshiaki; Nose, Yoshiaki

    2002-08-01

    Wireless LANs using radio waves have recently gained popularity for installation in hospitals. Because electromagnetic waves transmitted from mobile telephones have been shown to cause interference with medical electronic equipment, prudence would seem necessary when introducing radio wave communication devices into hospitals. Therefore, we tested the effect of wireless LAN communication on medical electronic equipment and the effect of electronic equipment on wireless LAN communication. We observed nine pieces of electronic equipment in the operating mode while transmitting radio waves from a wireless LAN. Even when the access point was put very close to the medical electronic equipment surface and data was transmitted, no malfunction of the equipment was observed. The medical electronic equipment caused little change in the effectiveness of the communication device, although radio waves emitted from electric knives and a remote patient monitor reduced the reception rate to about 60%. The communication speed of the wireless LAN was temporarily reduced only when a microwave oven was located close to and facing the access point. Because output in Japan is limited to a maximum of 10 mW wireless LAN following the IEEE802.11b standard should be able to be installed safely in Japanese hospitals. However, wireless LAN access points should not be installed near microwave ovens. PMID:12118814

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

    NASA Astrophysics Data System (ADS)

    Syage, Jack A.

    1992-11-01

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

  2. 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 manuscript, published in "ISEF 2007 - XIII International Symposium on Electromagnetic Fields in Mechatronics

  3. New method for efficient HIRF attenuation in aircraft cooling ducts

    Microsoft Academic Search

    Simon Rea; David Linton; E. Orr; Jonathan McConnell

    2003-01-01

    Radiation incident on aircraft can cause high intensity radiated fields (HIRF) to be present close to electronic systems. This threat is made more serious by the fact that some electronic systems need to be cooled via air ducts on the side of the aircraft, creating leakage points for electromagnetic radiation. One such electronic system is the Full Authority Digital Engine

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

    NASA Astrophysics Data System (ADS)

    Eliasson, B.; Lazar, M.

    2015-06-01

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

  5. The electromagnetic pulse environment and its influence on tactical electronic and communications equipment

    NASA Astrophysics Data System (ADS)

    McGrath, Steven J.

    1992-03-01

    The purpose of this thesis is to aid the military communicator in understanding the phenomenon that is known as the electromagnetic pulse (EMP). This thesis includes a brief history and definition of the EMP and a description of the various EMP environments. It also discusses the effects that an EMP can have on exposed electronic components and communications equipment. It provides a description of the major approaches that are used to reduce the harmful effects of an EMP. A discussion of the factors considered in a cost benefit analysis is included for the purpose of establishing cost and benefit considerations relevant to a system's evaluation. The thesis concludes that the decision of whether or not to protect electronic and communications equipment from an EMP depends on many factors, including the criticality of the equipment's mission and the cost of EMP hardening compared to the benefits received. It also concludes that the nation should maintain its EMP hardening effort for critical systems.

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

    SciTech Connect

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

    2011-05-15

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

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

    SciTech Connect

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

    2011-08-21

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

  8. 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.

  9. 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

  10. Effect of electronic anti-fouling treatment on fouling mitigation with circulating cooling-tower water

    Microsoft Academic Search

    Cheolho Bai

    2001-01-01

    The purpose of the present study was to investigate the effect of electronic anti-fouling (EAF) technology on fouling mitigation in a heat exchanger in an open cooling-tower system. Two tests were performed in a rectangular heat-transfer channel at 5 cycles of concentration: one without the EAF treatment and the other with the EAF treatment. The fouling resistance in the case

  11. Low Noise NbN Phonon-Cooled Hot-Electron Bolometer Mixers at 810 GHz

    Microsoft Academic Search

    C. Roesch; T. Lehnert; C. Schwoerer; M. Schicke; K. H. Gundlach; K. F. Schuster; F. Schaefer

    1998-01-01

    NbN phonon-cooled superconducting hot-electron bolometric mix- ers with quasi-optical coupling were fabricated in a self-aligned process by means of e-beam-lithography. The mixer element consists of a 5 nm thick NbN film sputtered on a fused quartz substrate. Noise perfor- mance was investigated in the frequency range of 798 to 813 GHz for intermediate frequencies from 1.0 to 1.75 GHz. Uncorrected

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

    SciTech Connect

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

    2012-07-01

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

  13. Nonlinear Interaction of Relativistic Electrons and Electromagnetic Ion Cyclotron Waves in a Two-wave Model

    NASA Astrophysics Data System (ADS)

    An, X.; Chen, L.; Bortnik, J.; Thorne, R. M.

    2013-12-01

    Nonlinear interaction of relativistic electrons with a monochromatic electromagnetic ion cyclotron wave was investigated extensively in previous studies. Here we extend this work to investigate wave particle interactions in a two-wave model. By varying the separation of the two wave numbers, we calculate the Chirikov parameter, which measures the degree of the overlap of the resonant islands in the phase portrait. We demonstrate that the resonant islands highly overlap over a large range of the wave number separation, depending on which three typical regimes are identified. 1) a degenerate regime in which the effect of the two waves can be approximated by one wave model; 2) a transition regime where the resonant latitude of one wave moves equatorward and finally drops out of resonance with the electrons; 3) a non-overlap region where one wave is resonant with the electrons and the other is not. In the degenerate region, the concepts from the single wave interaction, i.e., phase bunching and phase trapping, still apply. When the particle initial pitch angle or the wave amplitude decreases, the length of the range of the degenerate region increases. In the transition region, the motions of the electrons are stochastic. In the non-overlap region, only the resonant wave is responsible for the electron scattering while the nonresonant wave contributes little. As one important application in the realistic space environment, we demonstrate that EMIC wave interactions with electrons can be treated by a single wave if the range of wave frequencies is located inside the degenerate region.

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

    NASA Technical Reports Server (NTRS)

    Koch, L. Danielle; VanZante, Dale E.

    2006-01-01

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

  15. A room temperature, or moderately cooled, fast THz semiconductor hot electron bolometer

    NASA Astrophysics Data System (ADS)

    Dobrovolsky, V.; Sizov, F.

    2007-02-01

    A fast THz bolometer is proposed in which, unlike the conventional thermal one, electromagnetic radiation heats only electrons in a narrow gap semiconductor without its lattice inertial heating. Under determined conditions, this heating changes generation-recombination processes that cause the carrier number to decrease and the semiconductor resistance to rise. The Hg0.8Cd0.2Te detector noise equivalent power in the range of 77-300 K can reach ~10-11 W for frequencies of about 1 THz and signal gain frequency bandwidth of 1 Hz. Measurements with the device prototype confirmed the concept of the proposed bolometer creation.

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

    SciTech Connect

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

    1988-03-01

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

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

    SciTech Connect

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

    1987-01-01

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

  18. The interaction of electromagnetic wave and plasma wave in an electron beam-ion channel system

    SciTech Connect

    Su, D.; Tang, C. J. [Key Laboratory of High Energy Density Physics and Technology, Ministry of Education, Sichuan University, Chengdu, 610064 (China)

    2011-02-15

    The features of the waves and the instability induced by the interaction of electromagnetic (EM) wave with plasma wave in the electron beam-ion channel system are studied. Characteristics of waves in the system are displayed through the dispersion relation and two kinds of EM instabilities are found. The first one is excited by the interaction of the fast plasma wave and the forward EM wave, and the other one is induced by the coupling of the fast plasma wave and the backward EM wave, the numerical results show that this is caused by the virtual cathode oscillation. The conditions of these EM instabilities are given and the related physical mechanisms have been discussed in detail.

  19. 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.

  20. Foil Cooling for the Rep-Rated Electron Beam Pumped Electra Laser

    NASA Astrophysics Data System (ADS)

    Giuliani, J. L.; Hegeler, F.; Wolford, M. F.; Abdel-Khalik, S.

    2005-10-01

    The Electra program at the Naval Research Laboratory is developing the science and technologies for implementation of krypton-fluoride (KrF) lasers in inertial fusion energy. Large aperture KrF lasers are pumped by electron beams which transit a foil separating the gas target at >=1 atm pressure from the vacuum diode. A fraction of the beam energy is deposited in the foil and thus long term (>=10^8 shots), rep-rated (5 Hz) operation requires active cooling of the foil to prevent thermal yield relaxation and cycling fatigue. This paper will report on experimental data and theoretical analysis of two diverse approaches to foil thermal management: convective and conductive cooling. Convective turbulent cooling has been operational on the Electra main amp through the use of oscillating louvers within a gas recirculator containing the pumped lasing region. At 5 Hz the foil temperature (Tf) can be maintained at ˜400 ^oC for a 1 mil SS foil. Conduction cooling provides the simplest configuration with only the need for water channels in the ribs of the hibachi. For a 1 mil Al foil, Tf is predicted to be ˜140 ^oC at 5 Hz. Comparison of experimental and theoretical results and advanced foil materials will be discussed.

  1. Modelization For Electromagnetic Electron Scattering at Low Energies for Radiotherapy applications.

    NASA Astrophysics Data System (ADS)

    Nazaryan, Vahagn; Gueye, Paul

    2006-03-01

    Since release of the GEANT4 particle simulation toolkit in 2003, there has been a growing interest in its applications to medical physics. The applicability of GEANT4 to radiotherapy has been a subject of several investigations in recent years, and it was found to be of great use. Its low-energy model allows for electromagnetic interaction simulations down to 250 eV. The electron physics data are obtained from the Lawrence Livermore National Laboratory's Evaluated Electron Data Library (EEDL). At very lower energies (below 10 MeV), some of the tabulated data in EEDL have big uncertainties (more than 50%), and rely on various extrapolations to energy regions where there is no experimental data. We have investigated the variations of these cross-section data to radiotherapy applications. Our study suggests a strong need for better theoretical models of electron interactions with matter at these energies, and the necessity of new and more reliable experimental data. The progress towards such theoretical model will be presented.

  2. Charge symmetry breaking in electromagnetic nucleon form factors in elastic parity-violating electron-nucleus scattering

    NASA Astrophysics Data System (ADS)

    Miller, Gerald A.

    2015-05-01

    The effects of charge symmetry breaking in nucleon electromagnetic form factors on parity-violating elastic electron-12C scattering is studied and found to be much smaller than other known effects. The analysis of a planned experiment is discussed. Nuclear isospin violation is likely to provide the largest correction term.

  3. Decay instability of an extraordinary electromagnetic wave into whistler and magnetized electron plasma waves in fusion plasmas

    Microsoft Academic Search

    R. P. Sharma; A. Kumar

    1986-01-01

    Parametric decay instability of an extraordinary electromagnetic wave into a magnetized electron plasma wave and a whistler wave propagating at an angle with respect to the static magnetic field has been considered. Application of the present investigation to tandem mirrors and tokamaks has been pointed out. For example (i) for the tandem-mirror parameters at the second harmonic cyclotron resonance in

  4. Gyrotrons and dopplertrons - Electromagnetic wave generators based on coherent radiation from magneto-resonant, relativistic, electron beams

    Microsoft Academic Search

    V. L. Granatstein

    1978-01-01

    The application of magnetized, intense, relativistic-electron beams to the generation of electromagnetic radiation at wavelengths ranging from 10 cm down to a fraction of a millimeter has enabled significant advances to be made in peak power capabilities. The physical mechanisms are conveniently divided into three categories according to the experimental feature which determines the output wavelength. These categories are related

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  6. Powerful electromagnetic millimeter-wave oscillations produced by stimulated scattering of microwave radiation by relativistic electron beams

    Microsoft Academic Search

    G. G. Denisov; A. V. Smorgonskii; V. P. Gubanov; S. D. Korovin; V. V. Rostov; M. I. Yalandin

    1984-01-01

    The stimulated scattering of electromagnetic waves in microwave generators, in which a high-current electron beam excites either a backward wave (BWO) or a quasi-critical frequency wave (orotron) is investigated experimentally. The scattering occurs at the same electron beam and the high-frequency feedback is provided by the inhomogeneities of the electrodynamic system of the microwave generator itself. A power of several

  7. Ambient temperature or moderately cooled semiconductor hot electron bolometer for mm and sub-mm regions

    NASA Astrophysics Data System (ADS)

    Dobrovolsky, V. N.; Sizov, F. F.; Kamenev, Y. E.; Smirnov, A. B.

    2008-06-01

    A model of semiconductor hot electron bolometer (SHEB), in which electromagnetic radiation heats only electrons in narrow-gap semiconductor without its lattice slow-response heating, is considered. Free carrier heating changes the generation-recombination processes that are the reason of semiconductor resistance rise. It is estimated, that Hg0.8Cd0.2Te detector noise equivalent power (NEP) for mm and sub-mm radiation wavelength range can reach NEP ˜10-11 W at ?f = 1 Hz signal gain frequency bandwidth. Measurements performed at electromagnetic wave frequencies v = 36, 39, 55, 75 GHz, and at 0.89 and 1.58 THz too, with non-optimized Hg0.8Cd0.2Te antenna-coupled bolometer prototype confirmed the basic concept of SHEB. The experimental sensitivity Sv ˜2 V/W at T = 300 K and the calculated both Johnson-Nyquist and generation-recombination noise values gave estimation of SHEB NEP ˜3.5 × 10-10 W at the band-width ?f = 1 Hz and v = 36 GHz.

  8. 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.

  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. Simulation of electron transfer in trimer nanocluster embedded in unstructured nondissipative matrix in external electromagnetic field

    NASA Astrophysics Data System (ADS)

    Yaltychenko, O. V.; Kanarovskii, E. Y.

    2015-02-01

    In this paper it is offered the simplest microscopic model for the description of the nanocomposite material, which is found under action of external electromagnetic (electric) field. At that, the trimer nanocluster embedded in the weakly structured non-dissipative matrix (for example, the polymeric, organic or amorphous types) is modeled as three- center molecular complex with one "excess" tunneling electron and all its centers are considered together with account of theirs ligand environment. The proposed model description is suitable to the trimer nanoclusters of bridge type, and to the nanotrimers such type in which the ions of 3d-metals and theirs oxides have the various oxidation degrees, and also to other three-center molecular complexes of similar types. For posed problem a description of external and internal factors and analysis of their interconnections are performed. Herewith, the given model is also characterized by fact that in addition to the explicit connections of its basic factors they, furthermore, are implicitly interconnected. Then, the mathematical model is formulated so that to contain an optimal number of model parameters for a detailed description of considered factors and its interconnections. In the result of numerical simulation can to identify the electron localization regimes in the trimer nanocluster and the values of controlling model parameters responsible for switching between the obtained regimes.

  11. Photino bremsstrahlung in intense electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Kurilin, Alexander V.; Ternov, Aleksey I.

    1996-02-01

    We calculate the probability for the emission of a pair of photinos by an electron moving in a background electromagnetic field. The rate of the process e -> e?~?~ is estimated at different values of the field strength and electron energies. Comparing the cooling rate of some astrophysical objects via photino bremsstrahlung with another competing energy-loss mechanism we find new constraints on the selectron massesMe~R =Me~L >= 89.4 GeV.

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

    SciTech Connect

    Wang, G. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Litvinenko, V. N. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-05-21

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

  13. 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.

  14. 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.

  15. Low-temperature two-phase micro-channel cooling for high-heat-flux thermal management of defense electronics

    Microsoft Academic Search

    Jaeseon Lee; Issam Mudawar

    2008-01-01

    For a given heat sink thermal resistance and ambient temperature, the temperature of an electronic device rises fairly linearly with increasing device heat flux. This relationship is especially problematic for defense electronics, where heat dissipation is projected to exceed 1000 W\\/cm2 in the near future. Direct and indirect low temperature refrigeration cooling facilitate appreciable reduction in the temperature of both

  16. 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.

  17. Effective cooling of electronic components by boiling phase transition in microgravity

    NASA Astrophysics Data System (ADS)

    Straub, J.; Picker, G.; Winter, J.; Zell, M.

    1997-01-01

    Boiling heat transfer on a miniature heater has been studied under microgravity conditions during the IML 2 Space Shuttle Mission in 1994. These experiments are simulations for the application of the direct cooling of small electronic devices by boiling heat transfer in space. This becomes very important due to high thermal loads of modern electronic components. The results of this investigations are: Even at microgravity the heat transfer coefficients are very high and are even higher compared with other heater geometry. A remarkable influence of the gravity on the nucleate boiling heat transfer could not be observed, only in the transition and film boiling region a reduction up to 50 % was found. Several boiling modes have been observed during the experimental runs depending on the subcooling of the liquid, the liquid state, and the overall heat flux. Surface tension, wetting behavior, coalescence processes, the momentum of bubble formation, and thermocapillary convection play the most important role in boiling. The general statement can be made: boiling can be applied for cooling processes in microgravity.

  18. Semi-Classical and Quantum-Field Descriptions for the Non-Linear Electromagnetic Response of Many-Electron Systems

    NASA Astrophysics Data System (ADS)

    Jacobs, Verne

    2015-03-01

    Semi-classical and quantum-field descriptions for the non-linear electromagnetic response relevant to resonant pump-probe optical phenomena in quantized many-electron systems are formulated within a general reduced-density-matrix framework. Time-domain (equation-of-motion) and frequency-domain (resolvent-operator) formulations are developed in a unified and self-consistent manner. A preliminary semi-classical perturbation treatment of the electromagnetic interaction is adopted, in which the electromagnetic field is described as a classical field satisfying the Maxwell equations. It is emphasized that the development of a quantized-field approach will be essential for a fully self-consistent quantum-mechanical formulation. Compact Liouville-space operator expressions are obtained for the general (n'th order) non-linear electromagnetic-response tensors describing moving many-electron atomic systems. The tetradic matrix elements of the Liouville-space self-energy operators are evaluated for environmental collisional and radiative interactions. Work supported by the Office of Naval Research through the Basic Research Program at The Naval Research Laboratory.

  19. 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.

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

    PubMed

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

    2014-01-01

    The temperature in the crust of an accreting neutron star, which comprises its outermost kilometre, is set by heating from nuclear reactions at large densities, neutrino cooling and heat transport from the interior. The heated crust has been thought to affect observable phenomena at shallower depths, such as thermonuclear bursts in the accreted envelope. Here we report that cycles of electron capture and its inverse, ?(-) 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

  1. Pumped helium system for cooling positron and electron traps to 1.2 K

    NASA Astrophysics Data System (ADS)

    Wrubel, J.; Gabrielse, G.; Kolthammer, W. S.; Larochelle, P.; McConnell, R.; Richerme, P.; Grzonka, D.; Oelert, W.; Sefzick, T.; Zielinski, M.; Borbely, J. S.; George, M. C.; Hessels, E. A.; Storry, C. H.; Weel, M.; Müllers, A.; Walz, J.; Speck, A.

    2011-06-01

    Extremely precise tests of fundamental particle symmetries should be possible via laser spectroscopy of trapped antihydrogen ( H¯) atoms. H¯ atoms that can be trapped must have an energy in temperature units that is below 0.5 K—the energy depth of the deepest magnetic traps that can currently be constructed with high currents and superconducting technology. The number of atoms in a Boltzmann distribution with energies lower than this trap depth depends sharply upon the temperature of the thermal distribution. For example, ten times more atoms with energies low enough to be trapped are in a thermal distribution at a temperature of 1.2 K than for a temperature of 4.2 K. To date, H¯ atoms have only been produced within traps whose electrode temperature is 4.2 K or higher. A lower temperature apparatus is desirable if usable numbers of atoms that can be trapped are to eventually be produced. This report is about the pumped helium apparatus that cooled the trap electrodes of an H¯ apparatus to 1.2 K for the first time. Significant apparatus challenges include the need to cool a 0.8 m stack of 37 trap electrodes separated by only a mm from the substantial mass of a 4.2 K Ioffe trap and the substantial mass of a 4.2 K solenoid. Access to the interior of the cold electrodes must be maintained for antiprotons, positrons, electrons and lasers.

  2. Strong neutrino cooling by cycles of electron capture and decay in neutron star crusts

    SciTech Connect

    Schatz, Hendrik [Michigan State University, East Lansing] [Michigan State University, East Lansing; Gupta, Sanjib [Indian Institute of Technology, Kanpur] [Indian Institute of Technology, Kanpur; Moeller, Peter [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Beard, Mary [University of Notre Dame, IN] [University of Notre Dame, IN; Brown, Edward [Michigan State University, East Lansing] [Michigan State University, East Lansing; Deibel, A. T. [Michigan State University, East Lansing] [Michigan State University, East Lansing; Gasques, Leandro [University of Sao Paulo, BRAZIL] [University of Sao Paulo, BRAZIL; Hix, William Raphael [ORNL] [ORNL; Keek, Laurens [Georgia Institute of Technology, Atlanta] [Georgia Institute of Technology, Atlanta; Lau, Rita [National Superconducting Cyclotron Laboratory (NSCL)] [National Superconducting Cyclotron Laboratory (NSCL); Steiner, Andrew M [University of Washington, Seattle] [University of Washington, Seattle; Wiescher, Michael [University of Notre Dame, IN] [University of Notre Dame, IN

    2013-01-01

    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 dwarfs13 and type Ia supernovae, but hitherto was not considered in neutron stars, because previous models1, 2 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  4. 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.

  5. Relative stability of boiling of FC-72 and HFE-7100 with applications to electronic device cooling

    NASA Astrophysics Data System (ADS)

    Liu, Z. W.; Lin, W. W.; Lee, D. J.; Peng, X. F.

    2000-12-01

    This paper investigates the relative stability between nucleate and film boiling modes of FC-72 and HFE-7100, which have potential to electronic device cooling applications. Equilibrium heat flux, q c, which refers to as an index for measuring the relative stability of boiling, was obtained at a liquid subcooling of 0-20 K. Experimental results reveal that (1) q cincreases with liquid subcooling; (2) although the FC-72 exhibits a higher critical heat flux (CHF) than does the HFE-7100, somewhat unexpectedly, the equilibrium heat flux for the latter is greater than the former. Restated, at a prescribed heat flux, the risk to burnout for boiling of FC-72 is higher than that of HFE-7100. The shift in boiling curves interprets the experimental findings.

  6. Heat transfer studies of a flow-through module for electronics cooling. Master`s thesis

    SciTech Connect

    Yeniceri, E.

    1995-09-01

    The thermal performance characteristics of an electronics cooling Liquid Flow Through Module (FTM) were experimentally investigated. Different sets of experiments were conducted for each side of the FTM. A synthetic dielectric polyalphaolefin type coolant, Brayco Micronic 889, was used. Six etched foil type heaters were attached to one side of the FTM over the fluid flow path while three heaters were attached to the other side of the module. Inlet and outlet fluid temperatures as well as surface temperature data were acquired from both sides of the module for several different flow rate and power setting combinations to quantify the effectiveness of the FTM. Correlations, in terms of Reynolds and Stanton numbers were formulated according to the data for both sides of the module.

  7. 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

  8. 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

  9. Low-Temperature Two-Phase Microchannel Cooling for High-Heat-Flux Thermal Management of Defense Electronics

    Microsoft Academic Search

    Jaeseon Lee; Issam Mudawar

    2009-01-01

    For a given heat sink thermal resistance and ambient temperature, the temperature of an electronic device rises fairly linearly with increasing device heat flux. This relationship is especially problematic for defense electronics, where heat dissipation is projected to exceed 1000 W\\/cm2 in the near future. Direct and indirect low-temperature refrigeration cooling facilitate appreciable reduction in the temperature of both coolant

  10. Low-Cost Tracking Ground Terminal Designed to Use Cryogenically Cooled Electronics

    NASA Technical Reports Server (NTRS)

    Wald, Lawrence W.; Romanofsky, Robert R.; Warner, Joseph D.

    2000-01-01

    A computer-controlled, tracking ground terminal will be assembled at the NASA Glenn Research Center at Lewis Field to receive signals transmitted by the Glenn's Direct Data Distribution (D3) payload planned for a shuttle flight in low Earth orbit. The terminal will enable direct data reception of up to two 622-megabits-per-second (Mbps) beams from the space-based, K-band (19.05-GHz) transmitting array at an end-user bit error rate of up to 10(exp -12). The ground terminal will include a 0.9-m-diameter receive-only Cassegrain reflector antenna with a corrugated feed horn incorporating a dual circularly polarized, K-band feed assembly mounted on a multiaxis, gimbaled tracking pedestal as well as electronics to receive the downlink signals. The tracking system will acquire and automatically track the shuttle through the sky for all elevations greater than 20 above the horizon. The receiving electronics for the ground terminal consist of a six-pole microstrip bandpass filter, a three-stage monolithic microwave integrated circuit (MMIC) amplifier, and a Stirling cycle cryocooler (1 W at 80 K). The Sterling cycle cryocooler cools the front end of the receiver, also known as the low-noise amplifier (LNA), to about 77 K. Cryocooling the LNA significantly increases receiver performance, which is necessary so that it can use the antenna, which has an aperture of only 0.9 m. The following drawing illustrates the cryoterminal.

  11. A. C. Betz et al., Phys. Rev. Lett. (2012) Hot Electron Cooling by Acoustic Phonons in Graphene

    E-print Network

    Plaçais, Bernard

    2012-01-01

    A. C. Betz et al., Phys. Rev. Lett. (2012) Hot Electron Cooling by Acoustic Phonons in Graphene A the many possible applications for graphene are sensitive optical detectors, called bolometers of the vibrational warming. Like many other materials, graphene has two different types of vibrational waves. Higher

  12. Combined effect of constant high voltage electrostatic field and variable frequency pulsed electromagnetic field on the morphology of calcium carbonate scale in circulating cooling water systems.

    PubMed

    Zhao, Ju-Dong; Liu, Zhi-An; Zhao, Er-Jun

    2014-01-01

    Research on scale inhibition is of importance to improve the heat transfer efficiency of heat exchangers. The combined effect of high voltage electrostatic and variable frequency pulsed electromagnetic fields on calcium carbonate precipitation was investigated, both theoretically and experimentally. Using energy dispersive spectrum analysis, the predominant phase was found to be CaCO(3). The formed crystal phases mainly consist of calcite and aragonite, which is, in part, verified by theory. The results indicate that the setting of water flow velocity, and high voltage electrostatic and variable frequency pulsed electromagnetic fields is very important. Favorable values of these parameters can have a significant anti-scaling effect, with 68.95% of anti-scaling ratio for scale sample 13, while unfavorable values do not affect scale inhibition, but rather promoted fouling, such as scale sample 6. By using scanning electron microscopy analysis, when the anti-scaling ratio is positive, the particle size of scale was found to become smaller than that of untreated sample and the morphology became loose. The X-ray diffraction results verify that the good combined effect favors the appearance and growth of aragonite and restrains its transition to calcite. The mechanism for scale reduction is discussed. PMID:25259497

  13. Electromagnetic and gravitational responses of two-dimensional noninteracting electrons in a background magnetic field

    NASA Astrophysics Data System (ADS)

    Abanov, Alexander G.; Gromov, Andrey

    2014-07-01

    We compute electromagnetic, gravitational, and mixed linear response functions of two-dimensional free fermions in an external quantizing magnetic field at an integer filling factor. The results are presented in the form of the effective action and as an expansion of currents and stresses in wave vectors and frequencies of the probing electromagnetic and metric fields. In addition to the well-studied U (1) Chern-Simons and Wen-Zee terms we find a gravitational Chern-Simons term that controls the correction to the Hall viscosity due to the background curvature. We relate the coefficient in front of the term with the chiral central charge.

  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. 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.

  16. Are the Electromagnetic Whistlers Associated with Magnetotail Reconnection Driven by Temperature Anisotropy or by Electron Phase Space Holes?

    NASA Astrophysics Data System (ADS)

    Goldman, Martin V.; Newman, David L.; Eastwood, Jonathan; Lapenta, Giovanni

    2014-10-01

    Kinetic simulations of magnetotail reconnection and theoretical analysis have recently been used to show that bipolar fields associated with electron phase space holes on separatrices near an x-point can efficiently emit electromagnetic whistler waves. It is shown here from the same simulation at later times that hole emission of whistlers also occurs near the pile-up front (dipolarization front) associated with magnetotail reconnection. In addition, a more general kinetic theory analysis of ?erenkov emission of whistlers by holes is performed which includes electron temperature anisotropy and enables the comparison of ?erenkov emission of whistlers by holes with whistler instability due to temperature anisotropy in regions where both anisotropy and holes are present. Observations of whistlers and holes near dipolarization fronts [e.g.,] are discussed in the context of these studies. Research supported by NASA.

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

    PubMed

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

    2009-02-01

    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. PMID:19256646

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

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

    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 2.45GHz, 2.5kW electron cyclotron heating (ECH), whereas diagnostics are carried out with a lower power (10W) separate frequency (1-2.1GHz) 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 35mm, 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 (1mm) antenna was used. As the preliminary results, we detected signals that have three characteristics of EBW, i.e., short wavelength, backward propagation, and electrostatic.

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

    NASA Astrophysics Data System (ADS)

    Nishikawa, K.-I.; Buneman, O.; Neubert, T.

    1995-04-01

    We have restudied electron beam driven whistler waves with a 3-D electromagnetic particle code. In the initialization of the beam-plamsa system, 'quiet start' conditions were approached by including the poloidal magnetic field due to the current carried by beam electrons streaming along a background magnetic field. The simulation results show electomagnetic 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 associted with the beam mode may directly generate whistler waves. However, the simulation results indicate several inconsistencies with this picture: (1) the parallel (to the background magnetic field) wavelenght of the whistler wave is longer than that of the beam instability, (2) the parallel phase velocity of the whistler wave is smaller than that of the beam mode, and (3) whistler waves continue to be generated even after the beam mode space charge modulation looses its coherence. 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 involved in the generation of the whistler waves.

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

    NASA Astrophysics Data System (ADS)

    Kazinski, P. O.

    2013-12-01

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

  2. A Novel Approach for Cooling Electronics Using a Combined Heat Pipe and Thermoelectric Module

    Microsoft Academic Search

    Banjerd Saengchandr; Nitin V. Afzulpurkar

    The development of effective cooling systems for microprocessors, specifically for CPU and other computer chips, is greatly important due to g rowth of high speed performance chips, which operate at elevated heat rates. The same issues apply for a djacent units including RAM and HDD also contributing to overall generation of heat inside c omputer. Problem statement: Conventional cooling system

  3. Low noise NbN lattice-cooled superconducting hot-electron bolometric mixers at submillimeter wavelengths

    Microsoft Academic Search

    Jonathan Kawamura; Raymond Blundell; Cheuk-Yu Edward Tong; Gregory Gol'Tsman; Eugene Gershenzon; Boris Voronov; Sergey Cherednichenko

    1997-01-01

    Lattice-cooled superconducting hot-electron bolometric mixers are used in a submillimeter-wave waveguide heterodyne receiver. The mixer elements are niobium nitride film with 3.5 nm thickness and ?10 ?m2 area. The local oscillator power for optimal performance is estimated to be 0.5 ?W, and the instantaneous bandwidth is 2.2 GHz. At an intermediate frequency centered at 1.4 GHz with 200 MHz bandwidth,

  4. Novel approaches for the characterization of electromagnetic fields using electron Takeshi Kasama1,2

    E-print Network

    Dunin-Borkowski, Rafal E.

    to be transferred between the TEM specimen holder and a scanning electron microscope (SEM), a focused ion beam (FIB of up to ±70° with voltages applied to them in situ in the electron microscope. The second relates and electrostatic fields in materials in the transmission electron microscope (TEM) at a spatial resolution that can

  5. 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

  6. HIGH-ORDER MODELING OF AN ERL FOR ELECTRON COOLING IN THE RHIC LUMINOSITY UPGRADE USING MARYLIE/IMPACT.

    SciTech Connect

    RANJBAR,V.; BEN-ZVI,I.; PAUL, K.; ABELL, D.T.; TECH-X CORP.; KEWISCH, J.; RYNE, R.D.; QIANG, J.

    2007-06-25

    Plans for the RHIC luminosity upgrade call for an electron cooling system that will place substantial demands on the energy, current, brightness, and beam quality of the electron beam. In particular, the requirements demand a new level of fidelity in beam dynamics simulations. New developments in MARYLIE/IMPACT have improved both the space charge computations for beams with large aspect ratios and the beam dynamic computations for rf cavities. We present the results of beam dynamics simulations that include the effects of space charge and nonlinearities, and aim to assess the tolerance for errors and nonlinearities on current designs for a super-conducting ERL.

  7. Experimental demonstration of an electromagnetically pumped free-electron laser with cyclotron harmonic idlers. Summary report, January 1987-June 1988

    SciTech Connect

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

    1990-02-01

    A new type of electromagnetically pumped, three-wave free-electron laser (FEL) has been observed in which cyclotron harmonic waves act as idlers. In this experiment, a powerful electromagnetic pump wave replaced the usual magnetostatic wiggler. The pump wave was generated by a backward wave oscillator (8.4 GHz, 50 MW peak power) driven by an intense relativistic electron beam (625 kV, 2 kA, 100 ns). A grating spectrometer was used to scan the microwave frequency spectrum from 50 to 130 GHz, and powerful high-frequency radiation was observed in the form of an array of regularly spaced peaks. The positions of the peaks were observed to vary with the magnitude of the axial guide magnetic field in a manner which agrees with the dispersion relationship omega sub s = omega sub w + ( k sub w) (v sub g) + (k sub s) (v parallel) + l Omega sub 0 due to a three-wave FEL interaction in which the cyclotron beam waves act as idler where omega sub s, k sub s and omega sub w, k sub w are the frequency and wave number of scattered and pump waves, Omega sub 0 is the relativistic electron cyclotron frequency, l is the harmonic number, and v parallel is the axial beam velocity. Harmonic numbers l = 1 and 5 to 14 are identified while sweeping through the frequency ranges from 7 to 18 GHz and 50 to 130 GHz. The results exhibit excellent agreement with a simple theoretical model of the three-wave interaction.

  8. arXiv:1203.2753v1[cond-mat.mes-hall]13Mar2012 Hot electron cooling by acoustic phonons in graphene

    E-print Network

    Plaçais, Bernard

    arXiv:1203.2753v1[cond-mat.mes-hall]13Mar2012 Hot electron cooling by acoustic phonons in graphene extract accurate values of the electron-acoustic phonon coupling constant in monolayer graphene. Our on the interaction between electrons and acoustic phonons in mono-layer graphene. To this end, we have investigated

  9. Particle-in-cell simulations of velocity scattering of an anisotropic electron beam by electrostatic and electromagnetic instabilities

    SciTech Connect

    Fu, X. R., E-mail: xrfu@lanl.gov; Cowee, M. M.; Winske, D. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Liu, K. [Auburn University, Auburn, Alabama 36849 (United States)] [Auburn University, Auburn, Alabama 36849 (United States); Peter Gary, S. [Space Science Institute, Boulder, Colorado 80301 (United States)] [Space Science Institute, Boulder, Colorado 80301 (United States)

    2014-04-15

    The velocity space scattering of an anisotropic electron beam (T{sub ?b}/T{sub ?b}>1) flowing along a background magnetic field B{sub 0} through a cold plasma is investigated using both linear theory and 2D particle-in-cell simulations. Here, ? and ? represent the directions perpendicular and parallel to B{sub 0}, respectively. In this scenario, we find that two primary instabilities contribute to the scattering in electron pitch angle: an electrostatic electron beam instability and a predominantly parallel-propagating electromagnetic whistler anisotropy instability. Our results show that at relative beam densities n{sub b}/n{sub e}?0.05 and beam temperature anisotropies T{sub b?}/T{sub b?}?25, the electrostatic beam instability grows much faster than the whistler instabilities for a reasonably fast hot beam. The enhanced fluctuating fields from the beam instability scatter the beam electrons, slowing their average speed and increasing their parallel temperature, thereby increasing their pitch angles. In an inhomogeneous magnetic field, such as the geomagnetic field, this could result in beam electrons scattered out of the loss cone. After saturation of the electrostatic instability, the parallel-propagating whistler anisotropy instability shows appreciable growth, provided that the beam density and late-time anisotropy are sufficiently large. Although the whistler anisotropy instability acts to pitch-angle scatter the electrons, reducing perpendicular energy in favor of parallel energy, these changes are weak compared to the pitch-angle increases resulting from the deceleration of the beam due to the electrostatic instability.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  11. The spectral forms of the stimulated electromagnetic emission near the 3-rd electron gyroharmonic at the SPEAR heating facility

    NASA Astrophysics Data System (ADS)

    Yurik, Roman; Tereshchenko, Evgeny; Baddeley, Lisa

    The results of the stimulated electromagnetic emission (SEE) observations of the final heating campaign with the SPEAR (Space Plasma Exploration by Active Radar) heating facility are reported. The presented observations were carried out in November 2013 on the Spitsbergen archipelago. The SEE observations were undertaken using the Polar Geophysical Institute (PGI) HF-interferometer, situated about 30~km from SPEAR at the geophysical observatory in Barensburg. The HF interferometer was modified such that it was possible to measure the polarization parameters of the received signal. The observatory also contains additional diagnostic equipment, such as magnetometers and receiving station of the RTU PGI KSC RAS, which were also utilized during the campaign. As a result of the observations the spectral forms of steady-state stimulated electromagnetic emission were obtained when the SPEAR heating facility operate in the frequency range from 4.14 MHz to 4.26 MHz (about 0.1 off the electron gyro frequency) under the day-time conditions. Lisa Baddeley’s research is supported by the Research Council of Norway/CoE under contract 223252/F50. SPEAR is supported by the Norwegian Research Council (grant 191628). The authors acknowledge Russian Foundation for Basic Research (Grant No. 13-05-12005-OFI-M) for financial support and participants of the heating campaign.

  12. Structure of electromagnetic field excited by an electron bunch in a semi-infinite dielectric-filled waveguide.

    PubMed

    Onishchenko, I N; Sidorenko, D Yu; Sotnikov, G V

    2002-06-01

    The exact solution of a problem on electromagnetic field excitation by a thin annular charged bunch in a semi-infinite round cylindrical waveguide with metal sidewalls and solid homogeneous dielectric filling is obtained. Expressions for all components of electromagnetic field are derived. These formulas describe the excited field at any point and any moment of time. In contrast to previous works, where asymptotic methods (saddle-point technique) were used, we applied a number of successive conformal transformations of integration area in order to carry out the inverse Fourier transformation. Integration along the initial infinite straight-line contour was substituted by integration along the closed circular contour. This allowed us to separate out the integral presentation of the cylindrical Bessel function of first kind and obtain the final solution in the form of infinite converging series. The process of integration is presented in detail. Both cases, when the Cherenkov resonance condition is satisfied and when this condition is not satisfied, are considered. Spatial pictures of field excited by a finite-size electron bunch are calculated numerically and discussed. In the case of the Cherenkov resonance the drift of excited wake field after the bunch with group velocity is demonstrated, and in the nonresonance case the appearance of impulse of transition radiation and the presence of precursor of the signal are shown. PMID:12188840

  13. One- and two-dimensional simulations of electron beam instability: Generation of electrostatic and electromagnetic 2fp waves

    NASA Astrophysics Data System (ADS)

    Kasaba, Y.; Matsumoto, H.; Omura, Y.

    2001-09-01

    We have performed computer simulations of the self-consistent nonlinear evolution of electrostatic and electromagnetic 2fp waves excited by electron beams with electromagnetic particle code. In both one- and two-dimensional periodic systems an electrostatic 2fp wave is generated at twice the wave number of forward propagating Langmuir waves by wave-wave coupling. This wave grows with the forward propagating Langmuir wave in the nonlinear stage of the simulations. The electrostatic 2fp wave in the simulations is saturated at about -20~-30dB of that of the Langmuir waves. It is larger than the value expected from observations in the terrestrial electron foreshock. The electromagnetic 2fp wave is only excited in two-dimensional systems. The magnitude of the electromagnetic 2fp wave is correlated with the backward propagating Langmuir wave, not with the electrostatic 2fp wave. This result suggests that the electromagnetic 2fp wave is excited by the wave-wave coupling of forward and backward propagating Langmuir waves. The typical power density estimated from a reasonable amplitude of Langmuir wave is of the same order or much weaker than the value typically observed around the electron foreshock.

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

    NASA Astrophysics Data System (ADS)

    Khazanov, G.; Sibeck, D.; Tel'nikhin, A.; Kronberg, T.

    2014-08-01

    We adopt a canonical approach to describe the stochastic motion of relativistic belt electrons and their scattering into the loss cone by nonlinear EMIC waves. The estimated rate of scattering is sufficient to account for the rate and intensity of bursty electron precipitation. This interaction is shown to result in particle scattering into the loss cone, forming ˜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.

  15. 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.

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

    PubMed

    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. PMID:24593505

  17. 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 1.0–1.2 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. High current magnetized plasma discharges and electron beams for capture and cooling of charged leptons and hadrons

    SciTech Connect

    Hershcovitch, A.

    1997-07-01

    Nowadays most magnetic lenses used to capture and to focus pions and muons utilize azimuthal magnetic fields generated by large axial currents, like horns or lithium rods (or even a Z-pinch at GSI). Capture and focusing angle is proportional to the product of the current and length of the lens. State-of-the-art for these lenses is no more than 750 kA and 70 cm. A meter long, multi-MA, magnetized axial discharges were generated by the early days of fusion. Lenses based of such devices can increase the capture angle of pions, e.g., by more than a factor of 2. Electron beam cooling is presently achieved in storage rings by having charged particles interact with a co-moving electron beam. In these devices, typical parameters are electron beam currents of about 1 A, an interaction length of about 1 meter, and interaction time of about 30 msec. Multi-MA electron beams can be used for single-pass final stage cooling in a number of machines. Calculations for some applications, as well as other advantages indicate that these schemes deserve further more serious consideration.

  19. Three Dimensional, Single-crystal, Oxide NANOFENCES for Epitaxial Growth of Electronic, Magnetic or Electromagnetic Nanoscale-Devices

    NASA Astrophysics Data System (ADS)

    Goyal, Amit; Wee, Sung-Hun; More, Karren; Specht, Eliot

    2009-03-01

    A unique, three-dimensional (3D), single-crystal, MgO, NANOFENCE comprised of single crystal MgO nanowire units was synthesized via epitaxial growth on (100) SrTiO3 substrates. Individual single crystal MgO nanowire units comprising the nanofence were observed to have high aspect ratios with small diameters of 10-20 nm and long lengths from 100 nm up 1 ?m. X-ray diffraction shows that the 3D MgO nanofence has an epitaxial relation with (100) SrTiO3 substrates with only a single 100<100> orientation and with full-width-half-maximum values of (200) ?-scan and (110) ?-scan with 4.5o and 5.5o, respectively. Such nanofences offer a single crystal, 3D nanotemplate for epitaxial growth of wide-ranging, 3D, electronic, magnetic and electromagnetic nanodevices.

  20. 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.

  1. 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.

  2. Design aspects for Very High Energy Electron (150 to 250 MeV) acceleration for use in radiation therapy: Beam shaping, electromagnetic scanning

    Microsoft Academic Search

    Keith Stewart; Vadim Moskvin; Colleen DesRosiers

    2010-01-01

    The concept of Very High Energy Electrons (VHEE) of 150 to 250 MeV has been proposed as a new modality in radiation therapy. It offers several advantages over conventional photon therapy, particularly in regions with widely varying tissue densities. In this examination the main focus is on design aspects related to beam shaping and electromagnetic scanning. Beam shaping in this

  3. A study on the heating and diagnostic of a tokamak plasma by electromagnetic waves of the electron cyclotron range of frequencies

    Microsoft Academic Search

    Katsumichi Hoshino

    1989-01-01

    A study on the heating and diagnosis of tokamak plasma by electromagnetic waves of electron cyclotron range of frequency is summarized. The main results obtained are as follows. On the engineering and technology, the technology of injecting high frequency, large power millimeter waves into tokamak plasma was established by carrying out the design, manufacture and test of a 60 GHz,

  4. Coupling of transient ultra wide band electro-magnetic fields to complex electronic systems

    Microsoft Academic Search

    M. Camp; H. Garbe; F. Sabath

    2005-01-01

    In this paper the coupling of transient ultra wide band field pulses to complex electronic systems is determined. Different test setups of microcontroller circuits were used to investigate the coupling effects and to describe the injected interference parameters.

  5. Ion Gyro-Harmonic Structuring in the Stimulated Electromagnetic Emission Spectrum During Second Electron Gyro-Harmonic Heating

    NASA Astrophysics Data System (ADS)

    Scales, Wayne; Bernhardt, Paul; Samimi, Alireza; Bricinsky, Stanley; Selcher, Craig

    2012-07-01

    Recent observations of Stimulated Electromagnetic Emissions SEEs have shown structures ordered by the ion gyro-frequency. In particular, during experiments in which the heating frequency is near the second electron gyro-harmonic, unique discrete spectral features separated by the ion gyro-frequency have been observed within about 1 kHz of the pump frequency. On occasion, a broadband spectral feature near 500 Hz is observed that coexists with the ion gyro-harmonic spectral features. Explanations for these spectral features have been based on parametric decay of the pump field into upper hybrid/electron Bernstein and ion Bernstein and oblique ion acoustic waves at the upper hybrid layer. This presentation will first review important characteristics of these ion gyro-harmonic spectral features obtained during some recent experiments at the High Frequency Active Auroral Research HAARP facility. These characteristics are then compared to predications of an analytical model for three-wave parametric decay of the pump field into upper hybrid/electron Bernstein and ion Bernstein and oblique ion acoustic waves. It is shown from the analytical theory that important pump field parameters that influence the spectral characteristics include the angle of the pump field relative the background magnetic field, the frequency of the pump relative to the second gyro-harmonic, and the pump field strength. Two Dimensional Particle-In-Cell simulations are used to investigate aspects of the nonlinear evolution such as irregularity development and field aligned electron heating in more detail. These simulations show favorable comparisons with the analytical theory predications as well as the experimental observations. Finally, possibilities for utilizing the experimentally observed SEE spectra for diagnostic purposes are discussed.

  6. Development and testing of radiation and electromagnetic pulse hardened silicon carbide based electronics

    NASA Astrophysics Data System (ADS)

    Edmond, J. A.; Palmour, J. W.

    1991-02-01

    There were three primary objectives for this reporting period. The first was to epitaxially grow and fabricate low voltage (50 to 70 V) p-n junction rectifiers for subsequent avalanche energy testing (AET) at 10 micro second pulse widths. The results of this test are compared to the AET results for higher voltage rectifiers (400 to 500 V) reported last quarter. The second was to design and epitaxially grow a gated thyrister structure. Two structures yielding 80 to 150 V and 200 to 350 V breakover voltage at zero gate current have been grown. The third objective was to fabricate JFET devices with higher power output than those discussed in the previous report. As in the last report, to simulate the effects of an electromagnetic pulse (EMP) on a p-n junction device, reverse bias AET was performed. The difference between this experiment and those performed in the previous reporting period was that the breakdown voltage (Vbr) of the present diodes was substantially lower than in the former test. Previously, the Vbr of the diodes was generally in the 400 to 500 V range where one would expect that the passivating layer on the junction may greatly affect its avalanche energy capability. In this experiment, diodes with a Vbr of 50 to 70 V were fabricated and tested for their resistance to EMP effects.

  7. Nonlinear perpendicular propagation of ordinary mode electromagnetic wave packets in pair plasmas and electron-positron-ion plasmas

    SciTech Connect

    Kourakis, I.; Verheest, F.; Cramer, N. F. [Universiteit Gent, Sterrenkundig Observatorium, Krijgslaan 281, B-9000 Gent (Belgium) and Institut fuer Theoretische Physik, Lehrstuhl IV - Weltraum-und Astrophysik, Ruhr-Universitaet, Bochum, D-44780 Bochum (Germany); Universiteit Gent, Sterrenkundig Observatorium, Krijgslaan 281, B-9000 Gent (Belgium) and School of Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000 (South Africa); School of Physics, University of Sydney, New South Wales 2006 (Australia)

    2007-02-15

    The nonlinear amplitude modulation of electromagnetic waves propagating in pair plasmas, e.g., electron-positron or fullerene pair-ion plasmas, as well as three-component pair plasmas, e.g., electron-positron-ion plasmas or doped (dusty) fullerene pair-ion plasmas, assuming wave propagation in a direction perpendicular to the ambient magnetic field, obeying the ordinary (O-) mode dispersion characteristics. Adopting a multiple scales (reductive perturbation) technique, a nonlinear Schroedinger-type equation is shown to govern the modulated amplitude of the magnetic field (perturbation). The conditions for modulation instability are investigated, in terms of relevant parameters. It is shown that localized envelope modes (envelope solitons) occur, of the bright- (dark-) type envelope solitons, i.e., envelope pulses (holes, respectively), for frequencies below (above) an explicit threshold. Long wavelength waves with frequency near the effective pair plasma frequency are therefore unstable, and may evolve into bright solitons, while higher frequency (shorter wavelength) waves are stable, and may propagate as envelope holes.

  8. Calibration and performance tests of the Very-Front-End electronics for the CMS electromagnetic calorimeter

    E-print Network

    Paris-Sud XI, Université de

    V for the endcaps. Both types comprise five identi- cal and independent read-out channels. Each channel, process production and show that the CMS detector specifications are reached. I. INTRODUCTION On detector electronics unit with an integrated digital to analogue converter (DAC) programmed via an I2 C interface, which al

  9. Experimental Investigation on Electromagnetic Radiation Effects to an Electronic System Through EMP Source

    Microsoft Academic Search

    Tan Zhiliang; Zhang Rongqi; Xie PengHao

    2007-01-01

    The radiation effect experiment to a complicated electronic system by using of GW ultra-wide band (UWB) radiation source has been carried out. In cases of opening or closing the door of device under test (DUT) , the responses of test points on combination No.04 and No.08 of DUT have been measured. The response characteristics of test points on combination No.02

  10. Adsorption behavior of beryllium(II) on copper-oxide nanoparticles dispersed in water: A model for (7)Be colloid formation in the cooling water for electromagnets at high-energy accelerator facilities.

    PubMed

    Bessho, Kotaro; Kanaya, Naoki; Shimada, Saki; Katsuta, Shoichi; Monjushiro, Hideaki

    2014-01-01

    The adsorption behavior of Be(II) on CuO nanoparticles dispersed in water was studied as a model for colloid formation of radioactive (7)Be nuclides in the cooling water used for electromagnets at high-energy proton accelerator facilities. An aqueous Be(II) solution and commercially available CuO nanoparticles were mixed, and the adsorption of Be(II) on CuO was quantitatively examined. From a detailed analysis of the adsorption data measured as a function of the pH, it was confirmed that Be(II) is adsorbed on the CuO nanoparticles by complex formation with the hydroxyl groups on the CuO surface (>S-OH) according to the following equation: n > S-OH + Be(2+) ? (>S-O)n Be((2-n)+) + nH(+) (n = 2, 3) S : solid surface. The surface-complexation constants corresponding to the above equilibrium, ?(s,2) and ?(s,3), were determined for four types of CuO nanoparticles. The ?(s,2) value was almost independent of the type of nanoparticle, whereas the ?(s,3) values varied with the particle size. These complexation constants successfully explain (7)Be colloid formation in the cooling water used for electromagnets at the 12-GeV proton accelerator facility. PMID:25382043

  11. Frequency bandwidth and conversion loss of a semiconductor heterodyne receiver with phonon cooling of two-dimensional electrons

    SciTech Connect

    Shangina, E. L., E-mail: shangina@rplab.ru; Smirnov, K. V.; Morozov, D. V.; Kovalyuk, V. V.; Gol'tsman, G. N.; Verevkin, A. A. [Moscow State Pedagogical University (Russian Federation); Toropov, A. I. [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

    2010-11-15

    The temperature and concentration dependences of the frequency bandwidth of terahertz heterodyne AlGaAs/GaAs detectors based on hot electron phenomena with phonon cooling of two-dimensional electrons have been measured by submillimeter spectroscopy with a high time resolution. At a temperature of 4.2 K, the frequency bandwidth at a level of 3 dB (f{sub 3dB}) is varied from 150 to 250 MHz with a change in the concentration n{sub s} according to the power law f{sub 3dB} {proportional_to} n{sub s}{sup -0.5} due to the dominant contribution of piezoelectric phonon scattering. The minimum conversion loss of the semiconductor heterodyne detector is obtained in structures with a high carrier mobility ({mu} > 3 x 10{sup 5} cm{sup 2} V{sup -1} s{sup -1} at 4.2 K).

  12. Photon statistics of radiation scattered by relativistic electrons in an interfering electromagnetic field

    NASA Astrophysics Data System (ADS)

    Bertolotti, M.; Sibilia, C.; Perina, J.; Perinova, V.

    1984-09-01

    The statistical properties of backscattered radiation in the electron rest frame are studied when the radiation system is coupled to a 'reservoir' (electron beam). Anticorrelation effects are found to occur between scattered modes; super-Poissonian statistics also occurs in each emitted mode when the short-time approximation is adopted. In the radiation field, two incident modes at nearly the same frequency and two backscattered modes at nearly equal frequency are considered. The coherent state technique and the q-c number correspondence are employed, working in the Schroedinger picture with the generalized Fokker-Plack equation for the antinormal quasi-distribution function. The factorial moments are derived from the solution of that equation.

  13. Electromagnetic properties and electronic structure of the iron-based layered superconductor LaFePO

    Microsoft Academic Search

    Yoichi Kamihara; Masahiro Hirano; Hiroshi Yanagi; Toshio Kamiya; Yuji Saitoh; Eiji Ikenaga; Keisuke Kobayashi; Hideo Hosono

    2008-01-01

    Structural, electronic, and magnetic properties of undoped and aliovalent-ion (Ca, F)-doped LaFePO, which undergo superconducting transitions at transition temperatures (Tc) 4-7 K [Y. Kamihara , J. Am. Chem. Soc. 128, 10012 (2006)], were investigated. Tc of the samples varied from 2.4 to 5.5 K in the undoped samples and was increased up to ˜7K by Ca and F doping. The

  14. 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.

  15. Electron wave-packet dynamics in a relativistic electromagnetic field: 3-D analytical approximation

    Microsoft Academic Search

    J. Peatross; C. Müller; C. H. Keitel

    2007-01-01

    A solution to the Klein Gordon equation for a laser-driven electron is constructed from a superposition of Volkov states. The time-and space-dependent three-dimensional superposition integral can be evaluated analytically for an initial Gaussian momentum distribution when the expression for relativistic energy is expanded in a Taylor series over the scaled initial momenta. The solution preserves many complicated wave-packet dynamics in

  16. NbN phonon-cooled hot-electron bolometer mixer for terahertz heterodyne receivers

    Microsoft Academic Search

    Gregory N. Gol'tsman; Yuriy B. Vachtomin; Sergey V. Antipov; Matvey I. Finkel; Sergey N. Maslennikov; Konstantin V. Smirnov; Stanislav L. Polyakov; Sergey I. Svechnikov; Natalia S. Kaurova; Elisaveta V. Grishina; Boris M. Voronov

    2005-01-01

    We present the results of our studies of NbN phonon-cooled HEB mixers at terahertz frequencies. The mixers were fabricated from NbN film deposited on a high-resistivity Si substrate with an MgO buffer layer. The mixer element was integrated with a log-periodic spiral antenna. The noise temperature measurements were performed at 2.5 THz and at 3.8 THz local oscillator frequencies for

  17. Development of Nbn Hot Electron Bolometric Mixer for Terahertz Frequencies: the Phonon-Cooled Version

    Microsoft Academic Search

    Eyal Gerecht

    1998-01-01

    NbN HEB mixers represent a promising approach for achieving receiver noise temperatures of a few times the quantum noise limit at frequencies above 1 THz. NbN HEB devices have been shown to have sufficient bandwidth for applications in astronomy, remote sensing, and plasma diagnostics in the FIR range. The NbN HEB is a phonon cooled bolometer in which the energy

  18. Ultralight and stable composite structure to support and cool the ATLAS pixel detector barrel electronics modules

    Microsoft Academic Search

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

    2004-01-01

    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

  19. Direct Liquid Cooling of High Flux Micro and Nano Electronic Components

    Microsoft Academic Search

    Avram Bar-Cohen; Mehmet Arik; Michael Ohadi

    2006-01-01

    The inexorable rise in chip power dissipation and emergence of on-chip hot spots with heat fluxes approaching 1 =kW\\/cm2 has turned renewed attention to direct cooling with dielectric liquids. Use of dielectric liquids in intimate contact with the heat dissipating surfaces eliminates the deleterious effects of solid-solid interface resistances and harnesses the highly efficient phase-change processes to the critical thermal

  20. 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.

  1. Investigation of the Electromagnetic Radiation Emitted by Sub-GeV Electrons in a Bent Crystal.

    PubMed

    Bandiera, L; Bagli, E; Germogli, G; Guidi, V; Mazzolari, A; Backe, H; Lauth, W; Berra, A; Lietti, D; Prest, M; De Salvador, D; Vallazza, E; Tikhomirov, V

    2015-07-10

    The radiation emitted by 855 MeV electrons via planar channeling and volume reflection in a 30.5-?m-thick bent Si crystal has been investigated at the MAMI (Mainzer Mikrotron) accelerator. The spectral intensity was much more intense than for an equivalent amorphous material, and peaked in the MeV range in the case of channeling radiation. Differently from a straight crystal, also for an incidence angle larger than the Lindhard angle, the spectral intensity remains nearly as high as for channeling. This is due to volume reflection, for which the intensity remains high at a large incidence angle over the whole angular acceptance, which is equal to the bending angle of the crystal. Monte Carlo simulations demonstrated that incoherent scattering significantly influences both the radiation spectrum and intensity, either for channeling or volume reflection. In the latter case, it has been shown that incoherent scattering increases the radiation intensity due to the contribution of volume-captured particles. As a consequence, the experimental spectrum becomes a mixture of channeling and pure volume reflection radiations. These results allow a better understanding of the radiation emitted by electrons subjected to coherent interactions in bent crystals within a still-unexplored energy range, which is relevant for possible applications for innovative and compact x-ray or ?-ray sources. PMID:26207480

  2. The Start-to-End Simulation of Electron Beam in the RHIC E-cooling Facility (L-band option) with PARMELA

    E-print Network

    C-A/AP/95 March 2003 The Start-to-End Simulation of Electron Beam in the RHIC E-cooling Facility (L-band-cooling Facility(L-band option) with PARMELA Dong Wang, Ilan Ben-Zvi, Xiangyun Chang, Jorg Kewisch Collider energy- recovery, etc. A start-to-end simulation has been performed with L-band (1.3GHz) gun and linac

  3. 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

  4. 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.

  5. Simulation of Multi-Spacecraft Observed Energetic Electron Injection By the Electromagnetic Field of a Transient, Localized Dipolarizing Flux Bundle

    NASA Astrophysics Data System (ADS)

    Gabrielse, C.; Angelopoulos, V.; Runov, A.; Turner, D. L.

    2014-12-01

    Energetic particle injections in the near-Earth plasma sheet are critical for supplying particles and energy to the radiation belts and ring current. Their origin, however, has been elusive due to the lack of equatorial, multi-point observations. After the launch of NASA's Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission in 2007, intense electric fields and elevated energetic particle fluxes have been observed to accompany localized (1-4 RE wide) bursty bulk flows and to propagate from the mid-tail regions (at geocentric radial distances R > 25RE) towards Earth, up to and at times inside of geosynchronous orbit (GEO, R=6.6RE). Motivated by these observations, we model simultaneous multi-point observations of electron injections using guiding center approximation in prescribed but realistic electric and magnetic fields to better understand the nature of their acceleration. Modeling of electron injections assuming a localized, impulsive, dipolarizing flux bundle and its accompanying electric field transported from mid-tail to near-Earth at bursty flow speeds successfully reproduces the observations at multiple spacecraft. The impulsive, localized nature of the earthward-propagating electromagnetic pulse with attending vortical/tailward flow is what makes this model particularly effective in reproducing both the injection and the dispersed decrease in energy flux often observed simultaneously with the injection but at lower energies (~10-30 keV). The results suggest that particle acceleration and transport towards the inner magnetosphere can be thought of as a superposition of individual bursts of varying intensity and cadence depending on global geomagnetic activity levels.

  6. Nonlinear theory of the parametrically resonant interaction of electromagnetic waves in a relativistic-electron-beam plasma - Fundamental equations

    Microsoft Academic Search

    I. V. Dzedolik; V. P. Zakharov; V. V. Kulish

    1988-01-01

    A one-dimensionally limited, transversely homogeneous model of an artificial magnetodielectric is used to obtain a system of self-consistent nonlinear truncated equations for the parametrically resonant interaction of electromagnetic waves in an REB plasma. All the various types of transverse, periodically reversing electromagnetic pump and signal fields are taken into account, and the polarization, dispersion, impedance, and phase characteristics of the

  7. PHYSICAL REVIEW B 85, 245447 (2012) Modal decompositions of the local electromagnetic density of states and spatially resolved electron

    E-print Network

    2012-01-01

    PHYSICAL REVIEW B 85, 245447 (2012) Modal decompositions of the local electromagnetic density June 2012) We present universal modal decompositions of the quasistatic electromagnetic local density eigenmodes. A direct analogy with the well-known modal decomposition of the EMLDOS in the case

  8. 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 ns–500 ns. The full experimental system consists of a modified nanocalorimeter sensor, a custom-built in situ nanocalorimetry holder, a data acquisition system, and the DTEM itself, and is capable of thermodynamic and microstructural characterization of reactions over a range of heating rates (10{sup 2} K/s–10{sup 5} K/s) accessible by conventional (DC) nanocalorimetry. To establish its ability to capture synchronized calorimetric and microstructural data during rapid transformations, this work describes measurements on the melting of an aluminum thin film. We were able to identify the phase transformation in both the nanocalorimetry traces and in electron diffraction patterns taken by the DTEM. Potential applications for the newly developed system are described and future system improvements are discussed.

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

    PubMed

    Grapes, Michael D; LaGrange, Thomas; Friedman, Lawrence H; Reed, Bryan W; Campbell, Geoffrey H; Weihs, Timothy P; LaVan, David A

    2014-08-01

    Nanocalorimetry is a chip-based thermal analysis technique capable of analyzing endothermic and exothermic reactions at very high heating and cooling rates. Here, we couple a nanocalorimeter with an extremely fast in situ microstructural characterization tool to identify the physical origin of rapid enthalpic signals. More specifically, we describe the development of a system to enable in situ nanocalorimetry experiments in the dynamic transmission electron microscope (DTEM), a time-resolved TEM capable of generating images and electron diffraction patterns with exposure times of 30 ns-500 ns. The full experimental system consists of a modified nanocalorimeter sensor, a custom-built in situ nanocalorimetry holder, a data acquisition system, and the DTEM itself, and is capable of thermodynamic and microstructural characterization of reactions over a range of heating rates (10(2) K/s-10(5) K/s) accessible by conventional (DC) nanocalorimetry. To establish its ability to capture synchronized calorimetric and microstructural data during rapid transformations, this work describes measurements on the melting of an aluminum thin film. We were able to identify the phase transformation in both the nanocalorimetry traces and in electron diffraction patterns taken by the DTEM. Potential applications for the newly developed system are described and future system improvements are discussed. PMID:25173298

  10. 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.

  11. Low noise NbN lattice-cooled superconducting hot-electron bolometric mixers at submillimeter wavelengths

    SciTech Connect

    Kawamura, J.; Blundell, R.; Tong, C.E. [Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States); Goltsman, G.; Gershenzon, E.; Voronov, B.; Cherednichenko, S. [Moscow State Pedagogical University, Moscow, 119435 (Russia)] [Moscow State Pedagogical University, Moscow, 119435 (Russia)

    1997-03-01

    Lattice-cooled superconducting hot-electron bolometric mixers are used in a submillimeter-wave waveguide heterodyne receiver. The mixer elements are niobium nitride film with 3.5 nm thickness and {approximately}10 {mu}m{sup 2} area. The local oscillator power for optimal performance is estimated to be 0.5 {mu}W, and the instantaneous bandwidth is 2.2 GHz. At an intermediate frequency centered at 1.4 GHz with 200 MHz bandwidth, the double sideband receiver noise temperature is 410 K at 430 GHz. The receiver has been used to detect molecular line emission in a laboratory gas cell. {copyright} {ital 1997 American Institute of Physics.}

  12. 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}.

  13. The development of a room temperature electron cyclotron resonance ion source (Lanzhou electron cyclotron resonance ion source No. 4) with evaporative cooling technology at Institute of Modern Physics

    NASA Astrophysics Data System (ADS)

    Lu, W.; Sun, L. T.; Qian, C.; Guo, J. W.; Fang, X.; Feng, Y. C.; Yang, Y.; Ma, H. Y.; Zhang, X. Z.; Ma, B. H.; Xiong, B.; Guo, S. Q.; Ruan, L.; Zhao, H. W.

    2015-04-01

    LECR4 (Lanzhou electron cyclotron resonance ion source No. 4) has been successfully constructed at IMP and has also been connected with the Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ) systems. These source magnet coils are cooled through evaporative cooling technology, which is the first attempt with an ECR ion source in the world. The maximum mirror field is 2.5 T (with iron plug) and the effective plasma chamber volume is 1.2 l. It was designed to be operated at 18 GHz and aimed to produce intense multiple charge state heavy ion beams for the linear injector project SSC-Linac at IMP. In February 2014, the first analyzed beam at 18 GHz was extracted. During about three months' commissioning, some outstanding results have been achieved, such as 1.97 emA of O6+, 1.7 emA of Ar8+, 1.07 emA of Ar9+, and 118 euA of Bi28+. The source has also successfully delivered O5+ and Ar8+ ion beams for RFQ commissioning in April 2014. This paper will give a brief overview of the design of LECR4. Then, the latest results of this source at 18 GHz will be presented.

  14. Heat Pipe Integrated in Direct Bonded Copper (DBC) Technology for the Cooling of Power Electronics Packaging

    Microsoft Academic Search

    M. Ivanova; Y. Avenas; C. Schaeffer; J. B. Dezord; J. Schulz-Harder

    2005-01-01

    As the power densities of power components continue to grow, thermal issues are becoming extremely important and vital for the product quality. The primary causes of failures in electronic equipment are the excessive temperatures of the critical components, such as semiconductors and transformers. Power systems for space application are usually housed in completely sealed enclosures due to safety reasons. Since

  15. Heterodyne mixing in diffusion-cooled superconducting aluminum hot-electron bolometers

    Microsoft Academic Search

    I. Siddiqi; A. Verevkin; D. E. Prober; A. Skalare; W. R. McGrath; P. M. Echternach; H. G. Leduc

    2002-01-01

    We present microwave (30 GHz) measurements on aluminum superconducting hot-electron bolometer (HEB) mixers. Aluminum HEB mixers have a lower superconducting transition temperature than niobium and niobium nitride devices, and are predicted to have improved sensitivity and require less local oscillator power. The devices studied consist of a narrow superconducting aluminum microbridge with contacts comprised of thick aluminum, titanium, and gold.

  16. A study on the heating and diagnostic of a tokamak plasma by electromagnetic waves of the electron cyclotron range of frequencies

    NASA Astrophysics Data System (ADS)

    Hoshino, Katsumichi

    1989-09-01

    A study on the heating and diagnosis of tokamak plasma by electromagnetic waves of electron cyclotron range of frequency is summarized. The main results obtained are as follows. On the engineering and technology, the technology of injecting high frequency, large power millimeter waves into tokamak plasma was established by carrying out the design, manufacture and test of a 60 GHz, 400 kW high frequency heating system, and the design, manufacture and test of a heterodyne type electron cyclotron radiation multi-channel measuring system were carried out, and the technology of measuring the radiation from tokamak plasma with the time resolution of 10 (mu)s in multi-channel was established. On nuclear fusion reactor core engineering and plasma physics, the high efficiency electron heating of tokamak plasma by the incidence of fundamental irregular and regular waves at electron cyclotron frequency was verified. The discovery and analysis of the heating by electrostatic waves arising due to mode transformation from electromagnetic waves in upper hybrid resonance layer were carried out. By the incidence of second harmonic waves, the high efficiency electron heating of tokamak plasma was verified, and the heating characteristics were clarified.

  17. Electrohydrodynamic (EHD) cooled laptop

    Microsoft Academic Search

    N. E. Jewell-Larsen; H. Ran; Y. Zhang; M. K. Schwiebert; K. A. H. Tessera; A. V. Mamishev

    2009-01-01

    Forced air cooling with rotary fans is the most popular cooling solution for electronic products. However, increasing heat generation in microelectronics, and the demand for ever smaller portable devices, has resulted in heat fluxes and form-factors that push the limits of conventional rotary fan-based air cooling technology. Electrohydrodynamic (EHD) ionic wind pumps offer an attractive alternative to fans. In this

  18. Hot-electron cooling by acoustic and optical phonons in monolayers of MoS2 and other transition-metal dichalcogenides

    NASA Astrophysics Data System (ADS)

    Kaasbjerg, Kristen; Bhargavi, K. S.; Kubakaddi, S. S.

    2014-10-01

    We study hot-electron cooling by acoustic and optical phonons in monolayer MoS2. The cooling power P (Pe=P /n ) is investigated as a function of electron temperature Te (0-500 K) and carrier density n (1010-1013 cm-2) taking into account all relevant electron-phonon (el-ph) couplings. We find that the crossover from acoustic phonon dominated cooling at low Te to optical phonon dominated cooling at higher Te takes place at Te˜50 -75 K. The unscreened deformation potential (DP) coupling to the TA phonon is shown to dominate P due to acoustic phonon scattering over the entire temperature and density range considered. The cooling power due to screened DP coupling to the LA phonon and screened piezoelectric (PE) coupling to the TA and LA phonons is orders of magnitude lower. In the Bloch-Grüneisen (BG) regime, P ˜Te4(Te6) is predicted for unscreened (screened) el-ph interaction and P ˜n-1 /2(Pe˜n-3 /2) for both unscreened and screened el-ph interaction. The cooling power due to optical phonons is dominated by zero-order DP couplings and the Fröhlich interaction, and is found to be significantly reduced by the hot-phonon effect when the phonon relaxation time due to phonon-phonon scattering is large compared to the relaxation time due to el-ph scattering. The Te and n dependence of the hot-phonon distribution function is also studied. Our results for monolayer MoS2 are compared with those in conventional two-dimensional electron gases (2DEGs) as well as monolayer and bilayer graphene.

  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. PHYSICS 416. Electromagnetism. Lecturer: Tim Gorringe.

    E-print Network

    MacAdam, Keith

    PHYSICS 416. Electromagnetism. Lecturer: Tim Gorringe. Office: CP 273. Phone: 257-8740. Textbook: Electromagnetic Fields, R. Wangsness, 2nd Ed. Web page www.pa.uky.edu/gorringe/phy416/index.html Class hours: MWF-semester sequence on electromagnetic theory. 1 416/417 Course Objectives. The electromagnetic field binds electrons

  1. Ultra-fast dynamics of electron thermalization, cooling and transport effects in Ru(001)

    Microsoft Academic Search

    M. Lisowski; P. A. Loukakos; U. Bovensiepen; J. Stähler; C. Gahl; M. Wolf

    2004-01-01

    Time-resolved two-photon photoelectron spectroscopy is used to study the dynamics of non-equilibrium electron and hole distributions at bare and D 2O-covered Ru(001) following optical excitation (55-fs, 800-nm pulses) with variable fluence (0.04–0.6 mJ?cm -2). Within the first 0.5 ps we observe an ultra-fast transient of the excited-carrier population and energy density at the surface which is accompanied by pronounced deviations of the

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

    PubMed

    Hüdepohl, L; Müller, B; Janka, H-T; Marek, A; Raffelt, G G

    2010-06-25

    An 8.8M{?} electron-capture supernova was simulated in spherical symmetry consistently from collapse through explosion to essentially complete deleptonization of the forming neutron star. The evolution time (?9??s) is short because high-density effects suppress our neutrino opacities. After a short phase of accretion-enhanced luminosities (?200??ms), luminosity equipartition among all species becomes almost perfect and the spectra of ?{e} and ?{?,?} very similar, ruling out the neutrino-driven wind as r-process site. We also discuss consequences for neutrino flavor oscillations. PMID:20867357

  3. 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.

  4. Doubling of sensitivity and bandwidth in phonon-cooled hot-electron bolometer mixers

    NASA Astrophysics Data System (ADS)

    Baselmans, Jochem J. A.; Hajenius, Merlijn; Gao, Jianrong; Korte, Piet d.; Klapwijk, Teun M.; Voronov, Boris; Gol'tsman, Gregory

    2004-10-01

    NbN hot electron bolometer (HEB) mixers are at this moment the best heterodyne detectors for frequencies above 1 THz. However, the fabrication procedure of these devices is such that the quality of the interface between the NbN superconducting film and the contact structure is not under good control. This results in a contact resistance between the NbN bolometer and the contact pad. We compare identical bolometers, with different NbN - contact pad interfaces, coupled with a spiral antenna. We find that cleaning the NbN interface and adding a thin additional superconductor prior to the gold contact deposition improves the noise temperature and the bandwidth of the HEB mixers with more than a factor of 2. We obtain a DSB noise temperature of 950 K at 2.5 THz and a Gain bandwidth of 5-6 GHz. For use in real receiver systems we design small volume (0.15x1 micron) HEB mixers with a twin slot antenna. We find that these mixers combine good sensitivity (900 K at 1.6 THz) with low LO power requirement, which is 160 - 240 nW at the Si lens of the mixer. This value is larger than expected from the isothermal technique and the known losses in the lens by a factor of 3-3.5.

  5. Influence of the photonuclear effect on electron-neutrino-induced electromagnetic cascades under the Landau-Pomeranchuk-Migdal regime in standard rock

    E-print Network

    Mathieu Tartare; Didier Lebrun; François Montanet

    2012-11-29

    The observation of earth skimming neutrinos has been proposed as a rather sensitive method to detect ultra-high energy (UHE) cosmic neutrinos. Energetic cosmic neutrinos can interact inside the rock and produce leptons via a charged current interaction. In the case of an incoming electron neutrino undergoing a charged current interaction, the produced UHE electron will induce an underground electromagnetic shower. At high energy (above 7.7 TeV in standard rock), such showers are subject to LPM (Landau, Pomeranchuk and Migdal) suppression of the radiative processes cross sections (bremsstrahlung and pair production). The consequence of this suppression is that showers are elongated. This effect will increase the detection probability of such events allowing deeper showers to emerge with detectable energies. On the other hand, the photonuclear processes which are usually neglected in electromagnetic showers with respect to radiative processes, turn out to become dominant in the LPM regime and will reduce the shower length. In this work, we have performed a complete Monte Carlo study of an underground shower induced by UHE electrons by taking into account both the LPM suppression and the photonuclear interaction. We will discuss the effects of both of these processes on the shower length and on the detectability of such events by ground arrays or fluorescence telescopes. We show that limits on neutrino fluxes that were obtained using simulations that were obviously neglecting photonuclear processes are overoptimistic and should be corrected.

  6. 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

  7. EE335 Electromagnetic Interference Electromagnetic Interference (EMI)

    E-print Network

    Kaiser, Todd J.

    Electromagnetic Compatibility (EMC): The capability of electrical and electronic devices to operate of EMI EMI is the lack of EMC. EMI requirements 1) Source that generates noise 2) Coupling path to transmit the noise a. Radiated b. Conducted 3) Receptor that is susceptible to noise Interference Sources 1

  8. Amplification of an electromagnetic field at the scattering of the nonrelativistic electron by an ion in the external field of medium intensity for an arbitrary angle of the initial electron

    NASA Astrophysics Data System (ADS)

    Tsybul’nik, V. A.; Roshchupkin, S. P.

    2014-08-01

    We theoretically study the gain coefficient for a electromagnetic field, in the scattering of nonrelativistic electrons by ions in a elliptically polarized light wave. We obtain a simple analytical expression for a field amplification constant in logarithmic approach to an arbitrary angle of the initial electron. The formula supplements and extends the domain of applicability of the known Marcuse formula for the linear polarization in the presence of a weak field. It is demonstrated that the maximum gain is reached when the initial electron velocity directs along the major semi-axis of the polarization ellipse. In the range of optical frequencies, the gain coefficient of the laser radiation can be significant for relatively high powers of electron beams. Obtained results may be experimentally verified, for example, by the scientific facilities at the SLAC National Accelerator Laboratory and FAIR (Facility for Antiproton and Ion Research, Darmstadt, Germany).

  9. Stimulated electromagnetic emission and plasma line during pump wave frequency stepping near 4th electron gyroharmonic at HAARP

    NASA Astrophysics Data System (ADS)

    Grach, Savely; Sergeev, Evgeny; Shindin, Alexey; Mishin, Evgeny; Watkins, Brenton

    Concurrent observations of stimulated (secondary) electromagnetic emissions (SEE) and incoherent plasma line (PL) backscatter from the MUIR radar during HF pumping of the ionosphere by the HAARP heating facility (62.4(°) °N, 145.15(°) W, magnetic inclination ? = 75.8^circ) with the pump wave (PW) frequency sweeps about the fourth electron gyroharmonic (4f_c) are presented. The PW frequency f0 was changed every 0.2 s in a 1-kHz step, i.e. with the rate of r_{f_0}=5 kHz/s. PW was transmitted at the magnetic zenith (MZ). Prior to sweeping, PW was transmitted continuously (CW) during 2 min at f_0 = 5730 kHz <4f_c to create the “preconditioned” ionosphere with small-scale magnetic field-aligned irregularities. During CW pumping, a typical SEE spectrum for f_0<4f_c, containing the prominent downshifted maxi?m (DM) shifted by Delta f_{DM} = f_{DM}-f_0approx-9 kHz, developed in 5-10 s after PW turn on. The PL echoes were observed during 2-3 s from the range dsim 220 km corresponding to the altitude slightly above PW reflection height. After sim5 s the PL echoes descended to dsim 210-212 km corresponding to the height h = d / (sinalpha) by sim 7 km below the height where f_0 = 4f_c. During frequency sweeps, two upshifted features appeared in the SEE spectrum for f_0> 4f_c, namely BUM_S and BUM_D. The former (stationary broad upshifted maxi?m) peaks at Delta f_{BUMs} approx f0 - nfc (d) + 15-20 kHz and is a typical SEE spectral feature. The latter, the dynamic BUM_D at smaller Delta f, is observed only at high pump powers (ERP=1.7 GW) and corresponds to artificial descending plasma layers created in the F-region ionosphere [1]. In the experiment in question, the BUM_D was present for f_0> f^*, where f^* was 5805-5815 kHz during stepping up and sim 10 kHz less for stepping down, and located 8-10 km below the background F-layer. The mini?m DM which indicated that f_0=4f_c=f_{uh} in the background ionospheric plasma, was sim 5760 kHz. The PL was observed only for f_0< f^* and mainly from altitudes h where f_0 <4f_c. The height h decreased with increasing f_0 in accordance with the altitude dependence 4f_c(h), the difference Delta f_g = f_0 - 4f_c was kept constant during either sweeping up [-(4-8 kHz)] or sweeping down [-(18-22 kHz)]. This corresponds to the difference between the altitude where f_0=4f_c and the PL generation altitude by Delta h sim 1.5-3 km and 7-8 km, respectively. During stepping up, the PL was observed also from the ranges where f_0 > 4f_c. In this case we obtained Delta f_g sim 8-13 kHz corresponding to Delta h sim - 4 km. The PL has never been observed for f_0>f^*$. \\ 1. Sergeev E., Grach S., et al. //Phys. Rev. Lett., 110 (2013), 065002.

  10. Zero-field detection of spin dependent recombination with direct observation of electron nuclear hyperfine interactions in the absence of an oscillating electromagnetic field

    NASA Astrophysics Data System (ADS)

    Cochrane, C. J.; Lenahan, P. M.

    2012-12-01

    Electrically detected magnetic resonance (EDMR) involves the electron paramagnetic resonance (EPR) study of spin dependent transport mechanisms such as spin dependent tunneling and spin dependent recombination (SDR) in solid state electronics. Conventional EPR measurements generally require strong static magnetic fields, typically 3 kG or greater, and high frequency oscillating electromagnetic fields, typically 9 GHz or higher. In this study, we directly demonstrate that, in the absence of the oscillating electromagnetic field, a very large SDR response (?1%) can be detected at zero magnetic field with associated hyperfine interactions at extremely low magnetic fields in a silicon carbide (SiC) diode at room temperature. The zero-field SDR (ZFSDR) response that we detect is unexpected in the conventional detection scheme of SDR via EDMR. We believe that our observations provide fundamental physical understanding of other recently reported zero-field phenomena such as singlet triplet mixing in double quantum dots and low-field giant magnetoresistance in organic semiconductors. Our work provides an unambiguous demonstration that the zero-field phenomenon we observe involves SDR. Measurements reported herein indicate that extremely useful low-field SDR and ZFSDR results can be acquired simply and inexpensively in systems of technological importance. This work also suggests the potential use of this new physics in applications including absolute magnetometry with self-calibration, spin based memories, quantum computation, and inexpensive low-field EDMR spectrometers for wafer/probing stations.

  11. Noise Temperature and Absorbed LO Power Measurement Methods for NbN Phonon-Cooled Hot Electron Bolometric Mixers at Terahertz Frequencies

    Microsoft Academic Search

    Harald F. Merkel; Pavel A. Yagoubov; Matthias Kroug; Pourya Khosropanah; Erik L. Kollberg; Gregory N. Gol'tsman; Eugene M. Gershenzon

    1998-01-01

    In this paper the absorbed LO power requirements and the noise performance of NbN based phonon-cooled hot electron bolometric (HEB) quasioptical mixers are investigated for RF frequencies in the 0.55-1.1 range The minimal measured DSB noise temperatures are about 500 K at 640 GHz, 600 K at 750 GHz, 850 K at 910 GHz and 1250 K at 1.1 THz.

  12. Noise temperature and local oscillator power requirement of NbN phonon-cooled hot electron bolometric mixers at terahertz frequencies

    Microsoft Academic Search

    P. Yagoubov; M. Kroug; H. Merkel; E. Kollberg; G. Gol'Tsman; S. Svechnikov; E. Gershenzon

    1998-01-01

    In this letter, the noise performance of NbN-based phonon-cooled hot electron bolometric quasioptical mixers is investigated in the 0.55-1.1 THz frequency range. The best results of the double-sideband (DSB) noise temperature are: 500 K at 640 GHz, 600 K at 750 GHz, 850 K at 910 GHz, and 1250 K at 1.1 THz. The water vapor in the signal path

  13. 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

  14. Trapping of high-energy electrons into regime of surfatron acceleration by electromagnetic waves in space plasma

    SciTech Connect

    Erokhin, A. N.; Erokhin, N. S.; Milant'ev, V. P. [Peoples' Friendship University of Russia (Russian Federation)

    2012-05-15

    The phenomenon of trapping of weakly relativistic charged particles (with kinetic energies on the order of mc{sup 2}) into a regime of surfatron acceleration by an electromagnetic wave that propagates in plasma across a weak external magnetic field has been studied using nonlinear numerical calculations based on a solution of the relativistic equations of motion. Analysis showed that, for the wave amplitude above a certain threshold value and the initial wave phase outside the interval favorable for the surfing regime, the trajectory of a charged particle initially corresponds to its cyclotron rotation in the external magnetic field. For the initial particle energies studied, the period of this rotation is relatively short. After a certain number (from several dozen to several thousand and above) of periods of rotation, the wave phase takes a value that is favorable for trapping of the charged particle on its trajectory by the electromagnetic wave, provided the Cherenkov resonance conditions are satisfied. As a result, the wave traps the charged particle and imparts it an ultrarelativistic acceleration. In momentum space, the region of trapping into the regime of surfing on an electromagnetic wave turns out to be rather large.

  15. Completely Bound Motion of Electrons with Positive Energy near Protons in a Cool White Dwarf Photosphere Plasma with Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Koryagin, S. A.; Arsenyev, S. A.

    2015-06-01

    We proved that, under the conditions of an isolated magnetic white dwarf photosphere with strong magnetic field, an electron can perform the completely bound classic motion near a proton not only for the negative energy (as in an atom) but also for the positive energy (which usually corresponds to the free particles). Near the proton, the completely bound trajectories can occupy the significantly larger sector of the velocity directions than the free trajectories with the same energy. The integrated by frequency emissivity from the positive-energy bound electrons can exceed the bremsstrahlung emissivity from the free particles in the infrared. Nevertheless, the electromagnetic emission (and absorption) from the bound electrons is concentrated in the non-overlapping spectral lines.

  16. 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

  17. Comparison of Electromagnetic Field Signatures in Regions of Dispersive and Quasi-Static Electron Precipitation During the GREECE Sounding Rocket Flight

    NASA Astrophysics Data System (ADS)

    Bonnell, J. W.; Carruth, N.; Slagle, A.; Samara, M.; Michell, R.; Grubbs, G. A., II; Ogasawara, K.; Jahn, J. M.

    2014-12-01

    The NASA GREECE (Ground-to-Rocket Electrodynamics-Electrons Corelative Experiment) sounding rocket flew through two regions of electron precipitation associated with dynamic visual aurora on 03 Mar 2014. The first weaker precipitation region showed evidence of energy-time dispersion in the softer and weaker electron precipitation, while the later precipitation region showed evidence of quasi-static monoenergetic peaks in the somewhat harder precipitating electron spectra.Comparisons between the observed electromagnetic (EM) field (quasi-DC) and wave properties (0.1-8 kHz) in the two precipitation regions will be shown, including: measured plasma density; estimated spectral densities of E and B; derived polarization, cross-spectral phase and coherence, and parallel Poynting flux.The measured EM field parameters will be compared against extant models of static and dynamic coupling of the high- and low-altitude ionosphere in regions of active small-scale auroral features and precipitation to discriminate between viable models of the two sorts of auroral precipitation and acceleration.

  18. Electromagnetic Compatibility in Weapon Systems

    Microsoft Academic Search

    Fred J. Nichols

    1964-01-01

    The high density of electrical and electronic equipment in modern weapon systems, the extension of performance limits of both the equipment and the weapon systems and growth in complexity and quantity of systems have greatly aggravated the problem of insuring electromagnetic compatibility. Electromagnetic incompatibility can exist as soon as two or more of the most minor elements of the system

  19. Assessment of Electromagnetic Interference with Active Cardiovascular Implantable Electronic Devices (CIEDs) Caused by the Qi A13 Design Wireless Charging Board

    PubMed Central

    Seckler, Tobias; Jagielski, Kai; Stunder, Dominik

    2015-01-01

    Electromagnetic interference is a concern for people wearing cardiovascular implantable electronic devices (CIEDs). The aim of this study was to assess the electromagnetic compatibility between CIEDs and the magnetic field of a common wireless charging technology. To do so the voltage induced in CIEDs by Qi A13 design magnetic fields were measured and compared with the performance limits set by ISO 14117. In order to carry this out a measuring circuit was developed which can be connected with unipolar or bipolar pacemaker leads. The measuring system was positioned at the four most common implantation sites in a torso phantom filled with physiological saline solution. The phantom was exposed by using Helmholtz coils from 5 µT to 27 µT with 111 kHz sine-bursts or by using a Qi A13 design wireless charging board (Qi-A13-Board) in two operating modes “power transfer” and “pinging”. With the Helmholtz coils the lowest magnetic flux density at which the performance limit was exceeded is 11 µT. With the Qi-A13-Board in power transfer mode 10.8% and in pinging mode 45.7% (2.2% at 10 cm distance) of the performance limit were reached at maximum. In neither of the scrutinized cases, did the voltage induced by the Qi-A13-Board exceed the performance limits. PMID:26024360

  20. Assessment of Electromagnetic Interference with Active Cardiovascular Implantable Electronic Devices (CIEDs) Caused by the Qi A13 Design Wireless Charging Board.

    PubMed

    Seckler, Tobias; Jagielski, Kai; Stunder, Dominik

    2015-01-01

    Electromagnetic interference is a concern for people wearing cardiovascular implantable electronic devices (CIEDs). The aim of this study was to assess the electromagnetic compatibility between CIEDs and the magnetic field of a common wireless charging technology. To do so the voltage induced in CIEDs by Qi A13 design magnetic fields were measured and compared with the performance limits set by ISO 14117. In order to carry this out a measuring circuit was developed which can be connected with unipolar or bipolar pacemaker leads. The measuring system was positioned at the four most common implantation sites in a torso phantom filled with physiological saline solution. The phantom was exposed by using Helmholtz coils from 5 µT to 27 µT with 111 kHz sine?bursts or by using a Qi A13 design wireless charging board (Qi?A13?Board) in two operating modes "power transfer" and "pinging". With the Helmholtz coils the lowest magnetic flux density at which the performance limit was exceeded is 11 µT. With the Qi?A13?Board in power transfer mode 10.8% and in pinging mode 45.7% (2.2% at 10 cm distance) of the performance limit were reached at maximum. In neither of the scrutinized cases, did the voltage induced by the Qi?A13?Board exceed the performance limits. PMID:26024360

  1. Electromagnetic acoustic transduction using a pulsed electromagnet

    NASA Astrophysics Data System (ADS)

    Palmer, S. B.; Hernandez-Valle, J. F.; Dixon, S.

    2009-03-01

    Some early designs of Electromagnetic Acoustic Transducers (EMATs) used electromagnets to provide the strong magnetic field required for the transducer to operate. The advent of a new generation of permanent magnets such as NdFeB, with magnetic fields approaching 1T, meant that many EMAT designs switched over to using these small, compact and relatively inexpensive magnets. Typically, most modern EMATs make use of permanent magnets since they can exert high magnetic fields with compact structures. There are certain limitations when using permanent magnets, and their low Curie points of between 80-150C limit their practicality for high temperature testing without using water cooled transducers. In this work we have employed a pulsed electromagnet to provide the magnetic field. Pulsing the magnet dramatically reduces the average power required, keeping the supply more compact and less complex. It has the added advantage on ferritic steels, of resulting in much larger amplitude ultrasonic signals and improved signal to noise when compared with EMATs which use the strongest permanent magnets available.

  2. 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

  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. 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.

  5. 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 São Paulo, São 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.

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

    Microsoft Academic Search

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

    1999-01-01

    The electronic spectrum of germylidene (H2C&dblbnd;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

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

    Microsoft Academic Search

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

    1999-01-01

    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

  8. 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.

  9. 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.

  10. Cooling wall

    Microsoft Academic Search

    Nosenko

    1995-01-01

    Protecting the shells of blast furnaces is being resolved by installing cast iron cooling plates. The cooling plates become non-operational in three to five years. The problem is that defects occur in manufacturing the cooling plates. With increased volume and intensity of work placed on blast furnaces, heat on the cast iron cooling plates reduces their reliability that limits the

  11. Electromagnetic Hypersensitivity

    Microsoft Academic Search

    Norbert Leitgeb

    \\u000a Electromagnetic hypersensitive persons (EHS) attribute their nonspecific health symptoms to environmental electromagnetic\\u000a fields (EMF) of different sources in or outside their homes. In general, causal attribution is not restricted to specific\\u000a EMF frequencies but involves a wide range from extremely low frequencies (ELF) up to radio frequencies (RF) including mobile\\u000a telecommunication microwaves and radar. EHS argue that existing exposure limits

  12. Is cooling still cool?

    PubMed

    Subramaniam, Ashwin; Tiruvoipati, Ravindranath; Botha, John

    2015-03-01

    Therapeutic hypothermia (TH), where patients are cooled to between 32°C and 36°C 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 36°C had similar outcomes to cooling patients to 33°C. 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

  13. Electromagnetic reactions on light nuclei

    E-print Network

    Sonia Bacca; Saori Pastore

    2014-07-13

    Electromagnetic reactions on light nuclei are fundamental to advance our understanding of nuclear structure and dynamics. The perturbative nature of the electromagnetic probes allows to clearly connect measured cross sections with the calculated structure properties of nuclear targets. We present an overview on recent theoretical ab-initio calculations of electron-scattering and photonuclear reactions involving light nuclei. We encompass both the conventional approach and the novel theoretical framework provided by chiral effective field theories. Because both strong and electromagnetic interactions are involved in the processes under study, comparison with available experimental data provides stringent constraints on both many-body nuclear Hamiltonians and electromagnetic currents. We discuss what we have learned from studies on electromagnetic observables of light nuclei, starting from the deuteron and reaching up to nuclear systems with mass number A=16.

  14. Stochastic cooling at Fermilab

    SciTech Connect

    Marriner, J.

    1986-08-01

    The topics discussed are the stochastic cooling systems in use at Fermilab and some of the techniques that have been employed to meet the particular requirements of the anti-proton source. Stochastic cooling at Fermilab became of paramount importance about 5 years ago when the anti-proton source group at Fermilab abandoned the electron cooling ring in favor of a high flux anti-proton source which relied solely on stochastic cooling to achieve the phase space densities necessary for colliding proton and anti-proton beams. The Fermilab systems have constituted a substantial advance in the techniques of cooling including: large pickup arrays operating at microwave frequencies, extensive use of cryogenic techniques to reduce thermal noise, super-conducting notch filters, and the development of tools for controlling and for accurately phasing the system.

  15. Magnetism and Electromagnetism

    NSDL National Science Digital Library

    Kuphaldt, Tony R.

    All About Circuits is a website that â??provides a series of online textbooks covering electricity and electronics.â? 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 â?? 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).

  16. Bolometric effect and phonon cooling in graphene-superconductor junctions

    NASA Astrophysics Data System (ADS)

    Vora, Heli

    Graphene, a two-dimensional allotrope of graphite, possesses remarkable electronic properties which stem from the fact that the electrons in graphene are described by the Dirac-Weyl Hamiltonian. As a result, graphene exhibits a linear energy dispersion relation with zero effective mass. With its single-atomic-layer thickness, not only electrons but also phonons are of a two dimensional nature, differentiating graphene from the conventional semiconductor based two-dimensional electron gas systems. The combination of two-dimensional phonons, ultra small volume, low density of states and linear energy spectrum allows graphene to have weak electron-phonon coupling and extremely small electronic heat capacity. These properties make it a desirable material for use in a bolometer device, which is a sensitive electromagnetic radiation detector. We present a novel device design, which combines graphene with superconducting contacts and investigate its bolometric response. Two configurations of superconductor (S)- graphene(G)- superconductor(S) Josephson junction (SGS) and superconductor(S)- insulator(I)- graphene(G) (SIGIS) tunnel junction are studied. Devices with aluminum, niobium and niobium nitride as superconducting contacts are studied. In SIGIS tunnel junctions, titanium oxide is used as the barrier oxide to achieve high efficiency impedance matched bolometers. In these devices, hot electrons are created via application of microwave radiation and their relaxation to the bath temperature is studied. With the hot electrons effectively confined by the superconducting contacts, we demonstrate electron cooling via phonon interactions. This device geometry allows us to study electron-phonon coupling in single and bilayer graphene at low temperatures. In single layer graphene, a disorder-modified temperature dependence of electron-phonon cooling power is observed. And in bilayer graphene, it is shown that the electron-phonon coupling parameter has an inverse dependence on the chemical potential, opposite to that found in single layer graphene.

  17. 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.

  18. Prediction of Elastic Modulus + Anisotropy Using X-Ray and Electron Backscattered Diffraction Texture Quantification and Ultrasonic (Electromagnetic Acoustic Transducer) Measurements in Aluminum Sheets

    NASA Astrophysics Data System (ADS)

    Davis, C. L.; Strangwood, M.; Potter, M.; Dixon, S.; Morris, P. F.

    2008-03-01

    Crystallographic texture is generally measured using X-ray diffraction, performed off-line using small samples determining near-surface texture only; electron backscattered diffraction (EBSD) can also be used, but only samples relatively small areas. Ultrasonic methods determine elastic property anisotropy and texture, via orientation distribution coefficients (ODCs), and while there is substantial literature comparing ultrasonically determined properties with X-ray or neutron diffraction texture, there is little discussion about texture inhomogeneity (place to place in a sheet or through thickness) and sampling volume effects (X-ray compared to EBSD) on the accuracy of the correlations. In this article, the crystallographic texture of nominally pure aluminum and commercial aluminum alloy sheets has been determined by X-ray diffraction and EBSD and used to calculate the elastic anisotropy, which is then compared to ultrasonic electromagnetic acoustic transducer (EMAT) velocity anisotropy taking into account through-thickness texture variations. Significant and consistent spatial variability in texture occurs in the aluminum sheet samples (sheet edge to center and through thickness). Predictions of elastic anisotropy based on surface texture determination, as characterized by X-ray diffraction or surface EBSD, gave poor correlations with EMAT velocity anisotropy when the sample contained significant through thickness texture variations; however, accounting for this using multiple EBSD scans through thickness gave good correlations.

  19. Direct observation of transition to electron Bernstein waves from electromagnetic mode by three mode-conversion scenarios in the dipole confinement torus plasma

    NASA Astrophysics Data System (ADS)

    Uchijima, K.; Takemoto, T.; Morikawa, J.; Ogawa, Y.

    2015-06-01

    Direct measurement experiments on the mode conversion to the electron Bernstein wave (EBW) have been conducted in dipole confinement torus plasmas for three excitation scenarios; i.e. perpendicular injections of an eXtraordinary mode (X-mode) from the low- and high-magnetic-field sides, and the oblique injection of an Ordinary mode (O-mode) from the low-magnetic-field side. By inserting probe antennas into plasmas, wave propagation has been directly measured. At plasma conditions for the EBW excitation, several characteristics which indicate the mode conversion to the EBWs have been observed; i.e. a short wavelength wave, an electrostatic and longitudinal mode, backward propagation at the upper hybrid resonance (UHR) region. Meanwhile, the wavelengths experimentally observed might be slightly longer than those of theoretical prediction. In the case of the oblique injection of the O-mode, it has been identified that the window of the injection angle for the excitation of the EBW would be quite limited, and the optimum angle seems to be roughly in agreement with theory. These experimental results might support that the electromagnetic waves injected outside of torus plasmas reach to the UHR region and convert wave characteristics to the EBWs for three excitation scenarios.

  20. Three-dimensional electromagnetic strong turbulence: Dependence of the statistics and dynamics of strong turbulence on the electron to ion temperature ratio

    NASA Astrophysics Data System (ADS)

    Graham, D. B.; Cairns, Iver H.; Skjaeraasen, O.; Robinson, P. A.

    2012-02-01

    The temperature ratio Ti/Te of ions to electrons affects both the ion-damping rate and the ion-acoustic speed in plasmas. The effects of changing the ion-damping rate and ion-acoustic speed are investigated for electrostatic strong turbulence and electromagnetic strong turbulence in three dimensions. When ion damping is strong, density wells relax in place and act as nucleation sites for the formation of new wave packets. In this case, the density perturbations are primarily density wells supported by the ponderomotive force. For weak ion damping, corresponding to low Ti/Te, ion-acoustic waves are launched radially outwards when wave packets dissipate at burnout, thereby increasing the level of density perturbations in the system and thus raising the level of scattering of Langmuir waves off density perturbations. Density wells no longer relax in place so renucleation at recent collapse sites no longer occurs, instead wave packets form in background low density regions, such as superpositions of troughs of propagating ion-acoustic waves. This transition is found to occur at Ti/Te ? 0.1. The change in behavior with Ti/Te is shown to change the bulk statistical properties, scaling behavior, spectra, and field statistics of strong turbulence. For Ti/Te>rsim0.1, the electrostatic results approach the predictions of the two-component model of Robinson and Newman, and good agreement is found for Ti/Te>rsim0.15.

  1. 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.

  2. Electromagnetic Effects in SDF Explosions

    Microsoft Academic Search

    H Reichenbach; P Neuwald; A L Kuhl

    2010-01-01

    The notion of high ion and electron concentrations in the detonation of aluminized explosive mixtures has aroused some interest in electro-magnetic effects that the SDF charges might generate when detonated. Motivated by this interest we have started to investigate whether significant electro-magnetic effects show up in our small-scale experiments. However, the design of instrumentation for this purpose is far from

  3. Electromagnetic casting

    SciTech Connect

    Evans, J.W.; Kageyama, R. [Univ. of California, Berkeley, CA (United States); Deepak [Motorola Corp., Phoenix, AZ (United States); Cook, D.P. [Reynolds Metals Co., Richmond, VA (United States); Prasso, D.C. [Intel Corp., Aloha, OR (United States); Nishioka, S. [NKK Corp., Kawasaki (Japan)

    1995-12-31

    Electromagnetic casting (EMC) is a technology that is used extensively in the aluminum industry to cast ingots with good surface finish for subsequent rolling into consumer product. The paper reviews briefly some investigations from the eighties wherein models for EMC were developed. Then more recent work is examined wherein more realistic 3D models have been developed, the traditional studies of electromagnetic and magnetohydrodynamic phenomena have been supplemented with research on heat transport, and the stability of the metal free surface has been examined. The paper concludes with three generalizations concerning modeling that may have wider applicability than EMC.

  4. 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.

  5. 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.

  6. Natural cooling

    Microsoft Academic Search

    L. C. Fenster; A. J. Grantier

    1981-01-01

    With natural cooling, a process or area is cooled by outdoor air when the weather permits, and dependency on mechanical equipment is reduced. It should be used whenever conditions permit, and mechanical equipment should be brought on-line only when natural cooling cannot be employed. The results are minimized costs without lowered comfort or production levels, reduced costs for maintenance associated

  7. 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.

  8. 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.

  9. Electromagnetic compatibility

    Microsoft Academic Search

    H. Maidment

    1980-01-01

    The historical background to the growth in problems of electromagnetic compatibility (EMC) in UK Military aircraft is reviewed and the present approach for minimizing these problems during development is discussed. The importance of using representative aircraft for final EMC assessments is stressed, and the methods of approach in planning and executing such tests are also outlined. The present equipment qualification

  10. 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...

  11. Natural cooling

    SciTech Connect

    Fenster, L.C.; Grantier, A.J.

    1981-11-25

    With natural cooling, a process or area is cooled by outdoor air when the weather permits, and dependency on mechanical equipment is reduced. It should be used whenever conditions permit, and mechanical equipment should be brought on-line only when natural cooling cannot be employed. The results are minimized costs without lowered comfort or production levels, reduced costs for maintenance associated with higher levels of mechanical chiller system operation, and decreased dependence on expensive, nonrenewable energy sources. This article reviews several methods of natural cooling and provides a detailed computer-based economic evaluation of each. It discusses the air-side economizer, water-side natural cooling, and combination systems.

  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 Particle-in-Cell Simulations of the Solar Wind Interaction with Lunar Magnetic Anomalies: Ion and Electron Dynamics Under Varying Solar Wind Conditions.

    NASA Astrophysics Data System (ADS)

    Deca, J.; Divin, A. V.; Lapenta, G.; Lembege, B.; Markidis, S.; Horanyi, M.

    2014-12-01

    We present three-dimensional fully kinetic and electromagnetic simulations of the solar wind interaction with lunar crustal magnetic anomalies (LMAs). Using the implicit particle-in-cell code iPic3D, we confirm that LMAs may indeed be strong enough to stand off the solar wind from directly impacting the lunar surface forming a mini-magnetosphere, as suggested by spacecraft observations and theory. In contrast to earlier MHD and hybrid simulations, the fully kinetic nature of iPic3D allows to investigate the space charge effects and in particular the electron dynamics dominating the near-surface lunar plasma environment. We describe the general picture of the interaction of a dipole model centered just below the lunar surface under various solar wind and plasma conditions, and focus afterwards on the ion and electron kinetic behavior of the system. It is shown that the configuration is dominated by electron motion, because the LMA scale size is small with respect to the gyroradius of the solar wind ions. The dominant LMA interaction mechanism is also highly dependent on the solar wind and IMF conditions. Driven by strong pressure anisotropies, the mini-magnetosphere is also unstable over time, leading to only temporal shielding of the surface underneath. Our work opens new frontiers of research toward a deeper understanding of LMAs and is ideally suited to be compared with field or particle observations from spacecraft such as Kaguya (SELENE), Lunar Prospector or ARTEMIS. The ability to evaluate the implications for future lunar exploration as well as lunar science in general hinges on a better understanding of LMAs. This research has received funding from the European Commission's FP7 Program with the grant agreement SWIFF (project 2633430, swiff.eu) and EHEROES (project 284461, www.eheroes.eu). The simulations were conducted on the computational resources provided by the PRACE Tier-0 project 2011050747 (Curie) and 2013091928 (SuperMUC). This research was supported by the Swedish National Space Board, Grant No. 136/11. JD has received support through the HPC-Europa2 visitor programme (project HPC08SSG85) and the KuLeuven Junior Mobility Programme Special Research Fund.

  14. 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.

  15. a Spectroscopic Study of the Linear-Bent Electronic Transitions of Jet-Cooled BCl_2 and HBCl

    NASA Astrophysics Data System (ADS)

    Nagarajan, Ramya; Yang, Jie; Clouthier, Dennis J.

    2011-06-01

    Laser induced fluorescence (LIF) and single vibronic level emission spectra (SVL) of jet-cooled BCl_2 and HBCl have been measured. The radicals were produced in a pulsed electric discharge of a mixture of BCl_3/Ar and BCl_3/H_2/Ar, respectively. The LIF spectra of both radicals are congested due to overlapping bands from the boron and chlorine isotopes. In addition, the ground and first excited states are the two Renner-Teller components of a ^2? state split by a strong vibronic interaction. The Franck-Condon profile of the tilde{A}^2B_1 - tilde{X}^2A_1 band system of BCl_2 and the tilde{A}^2A'' - tilde{X}^2A' system of HBCl are characteristic of linear-bent excitations. Excited state bending progressions have been identified in both species using the LIF-sync scan procedure in which the monochromator is offset by a value corresponding to a ground state fundamental frequency of the target molecule and scanned simultaneously with the dye laser. LIF spectra of individual isotopes can thus be recorded. Ground state vibrational frequencies have been deduced from SVL spectra. The emission spectra for BCl_2, are dominated by progressions in the symmetric stretching (?_1) and bending (?_2) modes. In the case of HBCl, progressions in the bending (?_2) and BCl stretching (?_3) modes were observed.

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

    Microsoft Academic Search

    Valérie 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

  17. Modal decompositions of the local electromagnetic density of states and spatially resolved electron energy loss probability in terms of geometric modes

    NASA Astrophysics Data System (ADS)

    Boudarham, Guillaume; Kociak, Mathieu

    2012-06-01

    We present universal modal decompositions of the quasistatic electromagnetic local density of states (EMLDOS) of nanoparticles in the presence of dissipation and for arbitrary materials. This relies on a generic and universal description of the optical eigenmodes in arbitrary structures. In this description, already developed in various former theories, the eigenmodes are independent of the energy, scale invariant, and depend only on the structures shapes. For these reasons, we call the modes geometric eigenmodes. A direct analogy with the well-known modal decomposition of the EMLDOS in the case of nondissipative photonic modes is drawn in the special case of a material described by a Drude's model. Moreover, we show that this formalism is suitable to describe the electron energy loss spectroscopy and some scanning near optical field microscopy experiments. The link between such experiments and the mapping of the geometric mode is analyzed. In particular, this allows us to show that the delocalization of the inelastic signal can be interpreted as a convolution of the surface eigencharges at the boundary of the particle with the Coulombian interaction that arises in both experimental set up. A local density of states for the geometric eigenmodes depending only on the geometry of the particle is introduced, by analogy with the well-known EMLDOS for the photonic eigenmodes. This density of states and the related Green's functions, which have a very simple and concise form, are shown to be capable of generating all relevant quantities in the quasistatic approximation. Finally, we discuss the impact of the energy dispersion of the dielectric functions on the loss of spatial coherence of the geometric eigenmodes.

  18. 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.

  19. Chapter 18. Electromagnetic and Electronic Systems Electromagnetic and Electronic Systems

    E-print Network

    in the 1960's. Existing ultracapacitors utilize aluminum electrodes coated with a layer of activated carbon (no redox reaction), and use benign materials (primarily aluminum, carbon, and cellulose). However providing significantly higher power, faster recharge, easier recyclability, and almost unlimited lifetime

  20. IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 9, No. 2, JUNE 1999 4217 New Results for NbN Phonon-CooledHot Electron BolometricMixers Above 1 THz

    E-print Network

    Massachusetts at Lowell, University of

    N Phonon-CooledHot Electron BolometricMixers Above 1 THz E. Gerecht, C. F. Musante, H. Jian, and K in terms of DSB receivernoise temperature(2,800Kat 1.56THz). TheLO sourcefor thesemix- ers is a gas laser. Receivernoisetemperaturesbelow1THz are typically450-600K and areexpectedto graduallyapproachthese levelsabove 1THz aswell. Nb

  1. MEASURED RESULTS FOR NbN PHONON-COOLED HOT ELECTRON BOLOMETRIC MIXERS AT 0.6-0.75 THz, 1.56 THz, AND 2.5 THz

    E-print Network

    Yngvesson, K. Sigfrid

    MEASURED RESULTS FOR NbN PHONON-COOLED HOT ELECTRON BOLOMETRIC MIXERS AT 0.6-0.75 THz, 1.56 THz, AND 2.5 THz E. Gerecht, C. F. Musante, H. Jian, and K. S. Yngvesson Department of Electrical at frequencies above 1 THz. These HEB mixers have so far demonstrated a DSB noise temperature as low as 500 K

  2. 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.

  3. 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.

  4. Cooling wall

    SciTech Connect

    Nosenko, V.I. [Triangle Trading and Technology Corp., Laguna Hills, CA (United States)

    1995-07-01

    Protecting the shells of blast furnaces is being resolved by installing cast iron cooling plates. The cooling plates become non-operational in three to five years. The problem is that defects occur in manufacturing the cooling plates. With increased volume and intensity of work placed on blast furnaces, heat on the cast iron cooling plates reduces their reliability that limits the interim repair period of blast furnaces. Scientists and engineers from the Ukraine studied this problem for several years, developing a new method of cooling the blast furnace shaft called the cooling wall. Traditional cast iron plates were replaced by a screen of steel tubes, with the area between the tubes filled with fireproof concrete. Before placing the newly developed furnace shaft into operation, considerable work was completed such as theoretical calculations, design, research of temperature fields and tension. Continual testing over many years confirms the value of this research in operating blast furnaces. The cooling wall works with water cooling as well as vapor cooling and is operating in 14 blast furnaces in the Ukraine and two in Russia, and has operated for as long as 14 years.

  5. 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.

  6. Spectroscopy of jet-cooled AlMn and trends in the electronic structure of the 3d transition metal aluminides

    NASA Astrophysics Data System (ADS)

    Behm, Jane M.; Morse, Michael D.

    1994-10-01

    Jet-cooled diatomic AlMn has been spectroscopically investigated and is shown to possess a 5?i ground state deriving from the Al (3s23p1,2P0)+Mn (3d54s2,6S) separated atom limit. This implies that the aluminum atom favors a 3p? approach to the manganese atom, a result that is in agreement with previous studies on the related AlCa and AlZn molecules. The ground state bond length has been measured as 2.6384±0.0010 Å, a value which includes corrections due to spin-uncoupling effects in the X 5?i state. It is suggested that the 5?i state emerges as the ground state due to a particularly favorable configuration interaction with a low-lying 5?i state that derives from the interaction of Al (3s23p1,2P0)+Mn [3d6(5D)4s1,6D]. Combination of the atoms in this excited state leads to a strong ?2 covalent bond via a 3p?Al-4s?Mn interaction, which causes this excited electronic state to drop in energy so that it is expected to lie within a few thousand cm-1 of the ground electronic state. Following a discussion of the spectroscopic results on AlMn, an overall summary of the spectroscopic results on the 3d series of transition metal aluminides is presented, along with predictions of the ground electronic states of the as yet unobserved AlSc, AlTi, and AlFe molecules.

  7. Energy efficient liquid cooling

    Microsoft Academic Search

    Jeff Punch

    2008-01-01

    The theme of this paper is an investigation of the hydrodynamic performance of liquid pumps for electronics cooling applications, considered in conjunction with a range of primary heat exchangers. Pressure-flow characteristics of a set of geometrically- similar, miniature-scale centrifugal pumps are measured, and reductions in hydrodynamic efficiency are seen to occur below a critical Reynolds number. Six primary heat exchangers

  8. Overview of Recent Trends in Beam Cooling Methods and Technology

    Microsoft Academic Search

    Igor Meshkov; Dieter Moehl

    2006-01-01

    In this introductory paper, we try to give an idea of new developments in beam cooling since COOL03. We will concentrate on trends in electron cooling, stochastic cooling, muon cooling and beam crystallization; trends, which we think, will mark the future. We hope to touch upon some of the major ideas and topics that will be developed in detail at

  9. Colouring cryo-cooled crystals: online microspectrophotometry

    PubMed Central

    McGeehan, John; Ravelli, Raimond B. G.; Murray, James W.; Owen, Robin Leslie; Cipriani, Florent; McSweeney, Sean; Weik, Martin; Garman, Elspeth F.

    2009-01-01

    X-rays can produce a high concentration of radicals within cryo-cooled macromolecular crystals. Some radicals have large extinction coefficients in the visible (VIS) range of the electromagnetic spectrum, and can be observed optically and spectrally. An online microspectrophotometer with high temporal resolution has been constructed that is capable of measuring UV/VIS absorption spectra (200–1100?nm) during X-ray data collection. The typical X-ray-induced blue colour that is characteristic of a wide range of cryo-conditions has been identified as trapped solvated electrons. Disulphide-containing proteins are shown to form disulphide radicals at millimolar concentrations, with absorption maxima around 400?nm. The solvated electrons and the disulphide radicals seem to have a lifetime in the range of seconds up to minutes at 100?K. The temperature dependence of the kinetics of X-ray-induced radical formation is different for the solvated electrons compared with the disulphide radicals. The online microspectrophotometer provides a technique complementary to X-ray diffraction for analysing and characterizing intermediates and redox states of proteins and enzymes. PMID:19240328

  10. 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.

  11. 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.

  12. Electromagnetic leptogenesis

    NASA Astrophysics Data System (ADS)

    Bell, Nicole F.; Kayser, Boris J.; Law, Sandy S. C.

    2008-10-01

    We present a new leptogenesis scenario, where the lepton asymmetry is generated by CP-violating decays of heavy electroweak singlet neutrinos via electromagnetic dipole moment couplings to the ordinary light neutrinos. Akin to the usual scenario where the decays are mediated through Yukawa interactions, we have shown, by explicit calculations, that the desired asymmetry can be produced through the interference of the corresponding tree-level and one-loop decay amplitudes involving the effective dipole moment operators. We also find that the relationship of the leptogenesis scale to the light neutrino masses is similar to that for the standard Yukawa-mediated mechanism.

  13. Electromagnetism of rotating conductors revisited

    Microsoft Academic Search

    Dragan V. Redzic

    2002-01-01

    The charge distribution and electromagnetic fields in a rotating, charged conductor under stationary conditions are investigated, assuming that the electrons are at rest relative to the conductor. The basic equations are found, referred to the inertial rest frame of the rotational axis, in the relativistic case, and applied to the case of a cylindrical conductor. The results obtained are compared

  14. Electromagnetic study of multilayer media

    Microsoft Academic Search

    J. P. Booth; S. Brown

    2006-01-01

    This paper discusses a basic electromagnetic analysis of multilayer material used in a radome application. The purpose of this work is to investigate a possible new configuration for a missile seeker. The discussion is based on computer simulations with real world applications. This effort is being conducted in the RF Technology Division of the Applied Sensors, Guidance, and Electronics Directorate

  15. Cooling water system design

    Microsoft Academic Search

    Jin-Kuk Kim; Robin Smith

    2001-01-01

    Research on cooling systems to date has focussed on the individual components of cooling systems, not the system as a whole. Cooling water systems should be designed and operated with consideration of all the cooling system components because of the interactions between cooling water networks and the cooling tower performance. In re-circulating cooling water systems, cooling water from the cooling

  16. ATHENA X-IFU detector cooling chain

    NASA Astrophysics Data System (ADS)

    Branco, M. B. C.; Charles, I.; Butterworth, J.

    2014-07-01

    The TES (Transition Edge Sensors) micro-calorimeter detector technology in the X-IFU instrument for ATHENA (Astrophyics of the Hot and Energetic universe - Europe's next generation X-ray observatory ATHENA) will require cooling down to 50 mK, and a stable and quiet Electro-Magnetic and micro-vibrations environment. In order to achieve this temperature and environment, a cooling chain integrated in a compact cryostat with an optimized electromagnetic environment has to be developed. Critical technology developments are covered, such as mechanical cryocoolers, support structures, radiative and EMC shields, micro-vibrations reduction, and others.

  17. Creating an Electromagnet

    NSDL National Science Digital Library

    2014-09-18

    Student teams investigate the properties of electromagnets. They create their own small electromagnet and experiment with ways to change its strength to pick up more paper clips. Students learn about ways that engineers use electromagnets in everyday applications.

  18. 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.

  19. 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)

  20. Ventilative cooling

    E-print Network

    Graça, 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 ...

  1. An experimental and ab initio study of the electronic spectrum of the jet-cooled F{sub 2}BO free radical

    SciTech Connect

    Grimminger, Robert; Clouthier, Dennis J., E-mail: dclaser@uky.edu [Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055 (United States); Sheridan, Phillip M. [Department of Chemistry and Biochemistry, Canisius College, Buffalo, New York 14208 (United States)] [Department of Chemistry and Biochemistry, Canisius College, Buffalo, New York 14208 (United States)

    2014-04-28

    We have studied the B{sup ~} {sup 2}A{sub 1}–X{sup ~} {sup 2}B{sub 2} laser-induced fluorescence (LIF) spectrum of the jet-cooled F{sub 2}BO radical for the first time. The transition consists of a strong 0{sub 0}{sup 0} band at 446.5 nm and eight weak sequence bands to shorter wavelengths. Single vibronic level emission spectra obtained by laser excitation of individual levels of the B{sup ~} state exhibit two electronic transitions: a very weak, sparse B{sup ~}–X{sup ~} band system in the 450–500 nm region and a stronger, more extensive set of B{sup ~} {sup 2}A{sub 1}–A{sup ~} {sup 2}B{sub 1} bands in the 580–650 nm region. We have also performed a series of high level ab initio calculations to predict the electronic energies, molecular structures, vibrational frequencies, and rotational and spin-rotation constants in the X{sup ~} {sup 2}B{sub 2}, A{sup ~2}B{sub 1} and B{sup ~} {sup 2}A{sub 1} electronic states as an aid to the analysis of the experimental data. The theoretical results have been used as input for simulations of the rotationally resolved B{sup ~} {sup 2}A{sub 1}–X{sup ~} {sup 2}B{sub 2} 0{sub 0}{sup 0} LIF band and Franck-Condon profiles of the LIF and single vibronic level emission spectra. The agreement between the simulations obtained with purely ab initio parameters and the experimental spectra validates the geometries calculated for the ground and excited states and the conclusion that the radical has C{sub 2v} symmetry in the X{sup ~}, A{sup ~}, and B{sup ~} states. The spectra provide considerable new information about the vibrational energy levels of the X{sup ~} and A{sup ~} states, but very little for the B{sup ~} state, due to the very restrictive Franck-Condon factors in the LIF spectra.

  2. 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

  3. MAC Diagnostics RHIC Electron CoolingRHIC Electron Cooling

    E-print Network

    V] 54 spectrometer, Compton,... WCM, zero phasing, streak camera,... DCCT Pepper pot Compton plus streakERL Injector Portion of RHICof RHIC eCoolereCooler Legend: DCCT Button BPM Pepper pot BTF kicker Compton

  4. Electromagnetic Field Theory

    E-print Network

    Hart, Gus

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

  5. Self-consistent nonlinear analysis of the parametrically resonant interaction of two electromagnetic waves in a relativistic-electron-beam plasma

    Microsoft Academic Search

    I. V. Dzedolik; V. P. Zakharov; V. V. Kulish

    1988-01-01

    A self-consistent nonlinear theory is used to carry out a physical analysis of three-wave parametric resonance occurring during the interaction of REBs in periodically reversing electromagnetic fields. H-ubitron and Dopplertron amplification models are considered. Polarization effects, saturation during the achievement of asymptoptic and explosive regimes, and the generation mechanism of an additional H-ubiutron field are investigated. It is shown that

  6. Self-consistent nonlinear analysis of the parametrically resonant interaction of two electromagnetic waves in a relativistic-electron-beam plasma

    NASA Astrophysics Data System (ADS)

    Dzedolik, I. V.; Zakharov, V. P.; Kulish, V. V.

    1988-06-01

    A self-consistent nonlinear theory is used to carry out a physical analysis of three-wave parametric resonance occurring during the interaction of REBs in periodically reversing electromagnetic fields. H-ubitron and Dopplertron amplification models are considered. Polarization effects, saturation during the achievement of asymptoptic and explosive regimes, and the generation mechanism of an additional H-ubiutron field are investigated. It is shown that high values of interaction efficiency can be achieved in models with an optimal electrostatic support.

  7. Electromagnetic Gravitation

    NASA Astrophysics Data System (ADS)

    Montgomery, Jerry; Russell, Philmore

    2005-03-01

    Recent analysis of radio metric data from several space probes deployed by NASA indicate that they are being slowed by an anomalous constant acceleration with an average magnitude of 8x10-10m/s^2 oriented with respect to the sun. Analysis of their slowdown, in addition to many other anomalous astrophysical phenomena indicates that a negative curvature of the space-time continuum is produced by the electromagnetic radiation of the sun. The acceleration appears to have a close relation to the wavelength ?at which the sun radiates most intensely. The evidence that supports our hypothesis may also provide solutions to the flat rotation curve of the galaxy, and rogue stars and planets within the galaxy. Calculations using the data concerning the four probes result in the formula -a=c^2? which expresses a negative acceleration that is proportional to the speed of light divided by the peak wavelength, multiplied by a new constant k. The evidence also gives a strong indication that light, in addition to its particle-wave nature, produces gravitational field-like characteristics through interacting with the space-time continuum.

  8. Electromagnetic gravitation

    NASA Astrophysics Data System (ADS)

    Montgomery, Jerry, , Dr.

    2005-04-01

    Recent analysis of radio metric data from several space probes deployed by NASA indicate that they are being slowed by an anomalous constant acceleration with an average magnitude of 8x10-10m/s^2 oriented with respect to the sun. Analysis of their slowdown, in addition to many other anomalous astrophysical phenomena indicates that a negative curvature of the space-time continuum is produced by the electromagnetic radiation of the sun. The acceleration appears to have a close relation to the wavelength ?at which the sun radiates most intensely. The evidence that supports our hypothesis may also provide solutions to the flat rotation curve of the galaxy, and rogue stars and planets within the galaxy. Calculations using the data concerning the four probes result in the formula -a=c^2? which expresses a negative acceleration that is proportional to the speed of light divided by the peak wavelength, multiplied by a new constant k. The evidence also gives a strong indication that light, in addition to its particle-wave nature, produces gravitational field-like characteristics through interacting with the space-time continuum.

  9. 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 Â- 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 Â- 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).

  10. 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.

  11. Cooling Vest

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Because quadriplegics are unable to perspire below the level of spinal injury, they cannot tolerate heat stress. A cooling vest developed by Ames Research Center and Upjohn Company allows them to participate in outdoor activities. The vest is an adaptation of Ames technology for thermal control garments used to remove excess body heat of astronauts. The vest consists of a series of corrugated channels through which cooled water circulates. Its two outer layers are urethane coated nylon, and there is an inner layer which incorporates the corrugated channels. It can be worn as a backpack or affixed to a wheelchair. The unit includes a rechargeable battery, mini-pump, two quart reservoir and heat sink to cool the water.

  12. TESLA Report 2003-10 Studies of Electromagnetic Cascade Showers

    E-print Network

    TESLA Report 2003-10 Studies of Electromagnetic Cascade Showers Development in the TESLA Main Linac . . . . . . . . . . . . . . . . . . . . . 23 5 Simulations of the Behaviour of Field Emitted Electrons and Electromagnetic Shower Development vacuum, by quantum-mechanical tunneling of electrons from cold metal into vacuum in the presence

  13. Electromagnetically-Induced Transparency of Magnetized Plasma: New Approach to Electromagnetic Energy Compression and Particle Acceleration

    Microsoft Academic Search

    Gennady Shvets

    2004-01-01

    Magnetized plasma is completely opaque to electromagnetic waves propagating along the magnetic field when the wave frequency matches the electron cyclotron frequency. Remarkably, electron cyclotron absorption can be cancelled by adding a weak magnetic undulator, resulting in an Undulator-Induced Transparency (UIT) of the plasma^3-5. UIT is the plasma analog of the electromagnetically-induced transparency (EIT) of the atomic medium. Likewise, UIT

  14. Direct Liquid Cooling of High Flux Micro and Nano Electronic Components Boiling, evaporation, jet, and spray cooling, by suitable liquids such as fluorocarbons, might serve to control chip hot-spots and overheating

    Microsoft Academic Search

    Avram Bar-Cohen; Mehmet Arik; Michael Ohadi

    The inexorable rise in chip power dissipation and emergence of on-chip hot spots with heat fluxes approaching 1k W\\/cm 2 has turned renewed attention to direct cooling with dielectric liquids. Use of dielectric liquids in intimate contact with the heat dissipating surfaces eliminates the deleterious effects of solid-solid interface resistances and harnesses the highly efficient phase-change processes to the critical

  15. An electromagnetic actuated microvalve fabricated on a single wafer

    NASA Astrophysics Data System (ADS)

    Sutanto Bintoro, Jemmy

    Microvalves are essential components of the miniaturization of the fluidic systems to control of fluid flow in a variety of applications as diverse as chemical analysis systems, micro-fuel cells, and integrated fluidic channel arrangements for electronic cooling. Using microvalves, these systems offer important advantages: they can operate using small sample volumes and provide rapid response time. This PhD dissertation presents the world first electromagnetically actuated microvalve fabricated on a single wafer with CMOS compatibility. In this dissertation, the design, fabrication, and testing results of two different types of electromagnetic microvalves are presented: the on/off microvalve and the bistable microvalve with latching mechanism. The microvalves operate with power consumption of less than 1.5 W and can control the volume flow rate of DI water, or a 50% diluted methanol solution in the range 1--50 muL/min. The leaking rate of the on/off microvalve is the order of 30 nL/min. The microvalve demonstrated a response time for latching of 10 ms in water and 0.2 ms in air. This work has resulted in a US patent, application no. 10/699,210. Other inventions that have been developed as a result of this research are bidirectional, and bistable-bidirectional microactuators with latching mechanism, that can be utilized for optical switch, RF relay, micro mirror, nano indenter, or nano printings.

  16. 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.

  17. 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.

  18. 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.

  19. Cooling pancakes

    NASA Astrophysics Data System (ADS)

    Bond, J. R.; Centrella, J.; Szalay, A. S.; Wilson, J. R.

    1984-10-01

    One-dimensional numerical simulations of the collapse, shock heating, and subsequent thermal evolution of pancakes are described. The pressure is found to be relatively uniform within the shocked region and approximately equals the instantaneous ram pressure acting at the shock front. An analytic theory based on this result is developed which accurately describes the numerical calculations. The fraction of baryons which cool below a given temperature depends sensitively upon the total mass of the collapsing system and the baryon density parameter, and somewhat upon the inclusion of conduction at high mass. Anisotropic expansion factors are used to simulate transverse flow toward string-like structures. In some cases, the increased baryon density can overcome the effects of adiabatic compression to enhance cooling.

  20. Loschmidt's Cooling

    NASA Astrophysics Data System (ADS)

    Ramareddy, Vijayashankar; Talukdar, Ishan; Summy, Gil

    2008-05-01

    A quantum ?-kicked rotor can be understood theoretically using a kick to kick Floquet operator which has both kicking and free evolution terms. If time reversal is performed after t kicks, (by changing the pulse period and phase of the potential) the evolution of the system returns to the initial distribution in the next t kicks and results in a narrowing of the distribution which is equivalent to cooling [1]. The temperature has been predicted to go down by several orders of magnitude. We explore the experimental implementation of this cooling with a Bose-Einstein condensate kicked by a standing light wave. [1] J. Martin et. al. arXiv:0710.4860 (2007).

  1. Cool Science

    NSDL National Science Digital Library

    Science is quite cool, but you don't need to tell this to the dedicated team at the Howard Hughes Medical Institute. Their website, Cool Science, entertains questions of all kinds, encourages young scientists to "get their hands dirty", and also provides educators with a range of resources, including interactive media features, lesson plans, and lab exercises. These materials are contained with six primary sections: "For Educators", "Biointeractive", "For Curious Kids", and "Ask A Scientist". Educators of all stripes can use the "For Educators" area to focus in on resources organized by type, topic, grade level, and also to sign up for the resources RSS feed. Moving on, the "Biointeractive" area features archived video lectures, virtual labs, and another series of animations on stem cells, cancer, and immunology. There's a great deal to explore here, and it's a site that anyone with an interest in science will want to share with others.

  2. Cool Sportswear

    NASA Technical Reports Server (NTRS)

    1982-01-01

    New athletic wear design based on the circulating liquid cooling system used in the astronaut's space suits, allows athletes to perform more strenuous activity without becoming overheated. Techni-Clothes gear incorporates packets containing a heat-absorbing gel that slips into an insulated pocket of the athletic garment and is positioned near parts of the body where heat transfer is most efficient. A gel packet is good for about one hour. Easily replaced from a supply of spares in an insulated container worn on the belt. The products, targeted primarily for runners and joggers and any other athlete whose performance may be affected by hot weather, include cooling headbands, wrist bands and running shorts with gel-pack pockets.

  3. Motion of charged particles in an electromagnetic knot

    E-print Network

    M. Arrayás; J. L. Trueba

    2010-01-27

    In this paper we consider the classical relativistic motion of charged particles in a knotted electromagnetic field. After reviewing how to construct electromagnetic knots from maps between the three-sphere and the two-sphere, we introduce a mean quadratic radius of the energy density distribution in order to study some properties of this field. We study the classical relativistic motion of electrons in the electromagnetic field of the Hopf map, and compute their trajectories. It is observed that these electrons initially at rest are strongly accelerated by the electromagnetic force, becoming ultrarelativistic in a period of time that depends on the knot energy and size.

  4. A 3.5 Tesla Laboratory Electromagnet

    NASA Astrophysics Data System (ADS)

    Pooke, D. M.; Chamritski, V.; Gibson, S.; Fee, M.; King, T.; Staines, M. P.; Flower, N. E.; Buckley, R. G.

    2004-06-01

    We report the design and construction of a laboratory electromagnet utilizing HTS coils in an iron yoke with a magnetic flux density of 3.5 Tesla in a 50-mm air-gap. With continuing improvement in the performance of HTS "BSCCO" wire, several niche HTS magnet applications have become viable at current wire prices. In this instance, the HTS conductor confers the advantages of high field strength combined with compact size and energy efficiency, in an electromagnet of a format suitable for many materials' characterization techniques, such as vibrating-sample magnetometry, for which the current magnet will be employed. The magnet employs four HTS coils, with a total of 1.6 km of BSCCO wire, which are conduction cooled using a single-stage Gifford-McMahon cryocooler, delivering approximately 25 W of cooling power at the target 35 K operating temperature; HTS current leads are utilized to minimize heat leak to the cryogenic environment.

  5. The Electromagnetic Spectrum: FRONTLINE

    NSDL National Science Digital Library

    2004-02-20

    This video segment adapted from FRONTLINE introduces the electromagnetic spectrum and explains how the various types of electromagnetic waves are distinguished by the amount of energy each wave carries.

  6. Electromagnetic induction methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electromagnetic induction geophysical methods are finding greater and greater use for agricultural purposes. Electromagnetic induction methods measure the electrical conductivity (or resistivity) for a bulk volume of soil directly beneath the surface. An instrument called a ground conductivity meter...

  7. 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.

  8. 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 ...

  9. 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.

  10. 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

  11. 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

  12. 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

  13. Peltier cooling of superconducting current leads

    Microsoft Academic Search

    F. K. Gehring; M. E. Hüttner; 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 50–60 K below room temperature. We have developed

  14. 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

  15. New Physical Principles of Contact Thermoelectric Cooling

    Microsoft Academic Search

    Yu. G. Gurevich; G. N. Logvinov; O. Yu. Titov; J. Giraldo

    2002-01-01

    We suggest a new approach to theory of contact thermoelectric cooling (Peltier effect). The metal-metal, metal-n-type semiconductor, metal-p-type semiconductor, p-n junction contacts are analyzed. Both degenerate and nondegenerate electron and hole gases are considered. The role of recombination in the contact cooling effect is discussed for the first time.

  16. Semiconductor cooling by thin-film thermocouples

    NASA Technical Reports Server (NTRS)

    Tick, P. A.; Vilcans, J.

    1970-01-01

    Thin-film, metal alloy thermocouple junctions do not rectify, change circuit impedance only slightly, and require very little increase in space. Although they are less efficient cooling devices than semiconductor junctions, they may be applied to assist conventional cooling techniques for electronic devices.

  17. Prediction of Electromagnetic Compatibility problems based on artificial neural networks

    Microsoft Academic Search

    Xu Li; Jihui Yu; Yanju Zhu; Quandi Wang; Yongming Li

    2008-01-01

    Prediction of electronic equipments and systemspsila Electromagnetic Compatibility (EMC) issues at early develop stages is inevitable for achieving their EMC discipline. This paper proposes a method to fast predict EMC problems based on Artificial Neural Networks (ANN). By means of choosing relevant Electromagnetic Interference parameters to compose of input prediction features, using the back propagation (BP) neural network to construct

  18. Self-focusing of an electromagnetic pulse in the ionosphere

    Microsoft Academic Search

    Mohammad Faisal; Lalita Bhasin; Mahendra Singh Sodha

    2009-01-01

    In this paper, the self-focusing of electromagnetic pulsed beams having Gaussian and sine profiles in the ionosphere have been studied. The self-focusing of an electromagnetic pulse is caused by the nonlinearity in the dielectric function caused by the nonuniform distribution of electron temperature, determined by the Ohmic heating, solar radiation and energy loss in collisions with ions and neutrals. The

  19. 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.

  20. 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.

  1. 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, ...

  2. "Hearing" Electromagnetic Waves

    NASA Astrophysics Data System (ADS)

    Rojo, Marta; Muñoz, Juan

    2014-12-01

    In this work, an educational experience is described in which a microwave communication link is used to make students aware that all electromagnetic waves have the same physical nature and properties. Experimental demonstrations are linked to theoretical concepts to increase comprehension of the physical principles underlying electromagnetic waves. Moreover, students learn about the importance and historical development of communication systems, the basic principles of communication links, and the procedure to send information through an electromagnetic wave.1,2

  3. 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.

  4. 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.

  5. Electromagnetism Adapted for Life Science Students

    ERIC Educational Resources Information Center

    Gurr, F. M.; And Others

    1974-01-01

    Describes the study of electronics as a terminal course in electromagnetism. A lecture-laboratory approach is used with a strong emphasis on practical experience. Outlines the major topics of the lecture program and describes the activities used in the laboratory. (GS)

  6. Relativistic particle motion in nonuniform electromagnetic waves

    NASA Technical Reports Server (NTRS)

    Schmidt, G.; Wilcox, T.

    1973-01-01

    It is shown that a charged particle moving in a strong nonuniform electromagnetic wave suffers a net acceleration in the direction of the negative intensity gradient of the wave. Electrons will be expelled perpendicularly from narrow laser beams and various instabilities can result.

  7. Full-wave algorithms for model order reduction and electromagnet analysis of impedance and scattering

    E-print Network

    Klemas, Thomas J. (Thomas Jonas)

    2005-01-01

    As technology advances and sophisticated electronic systems achieve ubiquity, the demand for thorough, efficient Electromagnetic (EM) analysis continues to rise. The prohibitive costs of constructing and maintaining ...

  8. Vertical electromagnetic profiling (VEMP)

    Microsoft Academic Search

    Lytle

    1984-01-01

    Vertical seismic profiling (VSP) is based upon reception measurements performed in a borehole with a source near the ground surface. This technology has seen a surge in application and development in the last decade. The analogous concept of vertical electromagnetic profiling (VEMP) consists of reception measurements performed in a borehole with a source near the ground surface. Although the electromagnetic

  9. Building an Electromagnet

    NSDL National Science Digital Library

    VU Bioengineering RET Program,

    Students design and construct an electromagnet that must pick up 10 staples. They begin with only minimal guidance, and after the basic concept is understood, are informed of the properties that affect the strength of that magnet. They conclude by designing their own electromagnet to complete the challenge of separating scrap steel from scrap aluminum for recycling and share it with the class.

  10. The Electromagnetic Spectrum

    NSDL National Science Digital Library

    2012-08-03

    This is a lesson about the electromagnetic spectrum. Learners will read two pages of information about the electromagnetic spectrum and answer questions in an accompanying worksheet. This activity is from the Stanford Solar Center's All About the Sun: Sun and Stars activity guide for Grades 5-8 and can also accompany the Stanford Solar Center's Build Your Own Spectroscope activity.

  11. Introducing Electromagnetic Field Momentum

    ERIC Educational Resources Information Center

    Hu, Ben Yu-Kuang

    2012-01-01

    I describe an elementary way of introducing electromagnetic field momentum. By considering a system of a long solenoid and line charge, the dependence of the field momentum on the electric and magnetic fields can be deduced. I obtain the electromagnetic angular momentum for a point charge and magnetic monopole pair partially through dimensional…

  12. Electromagnetic Analysis: Concrete Results

    Microsoft Academic Search

    Karine Gandolfi; Christophe Mourtel; Francis Olivier

    2001-01-01

    Abstract Although the possibility of attacking smart - cards by analyz - ing their electromagnetic power radiation repeatedly appears in research papers, all accessible references evade the essence of reporting conclusive experiments where actual cryptographic algorithms such as des or rsa were successfully attacked This work describes electromagnetic experiments conducted on three dif - ferent cmos chips, featuring di erent

  13. "Hearing" Electromagnetic Waves

    ERIC Educational Resources Information Center

    Rojo, Marta; Munoz, Juan

    2014-01-01

    In this work, an educational experience is described in which a microwave communication link is used to make students aware that all electromagnetic waves have the same physical nature and properties. Experimental demonstrations are linked to theoretical concepts to increase comprehension of the physical principles underlying electromagnetic…

  14. Constraining scenarios of the soft/hard transition for the pion electromagnetic form factor with expected data of 12 GeV Jefferson Lab experiments and of the electron-ion collider

    NASA Astrophysics Data System (ADS)

    Troitsky, S. V.; Troitsky, V. E.

    2015-02-01

    It has been shown previously [S. V. Troitsky and V. E. Troitsky, Phys. Rev. D 88, 093005 (2013)] that a nonperturbative relativistic constituent-quark model for the ? -meson electromagnetic form factor allows for a quantitative description of the soft/hard transition, resulting in the correct quantum-chromodynamical asymptotics, including normalization, from the low-energy data without further parameter tuning. This happens universally whenever the constituent-quark mass is switched off. The energy range where the transition happens is therefore determined by the quark-mass running at intermediate energies and is not tightly constrained theoretically. Here we consider possible ways to pin down this energy range with coming experimental data. We demonstrate that expected experimental uncertainties of the 12 GeV Jefferson Lab data are larger than the span of predictions of the model, so these data might be used for testing the model but not for determination of the soft/hard transition scale. Contrarily, the projected electron-ion collider will be capable of pinning down the scale.

  15. Constraining scenarios of the soft/hard transition for the pion electromagnetic form factor with expected data of 12-GeV Jefferson Lab experiments and of the Electron-Ion Collider

    E-print Network

    Troitsky, S V

    2015-01-01

    It has been shown previously [PRD 88 (2013) 093005, arXiv:1310.1770] that a non-perturbative relativistic constituent-quark model for the $\\pi$-meson electromagnetic form factor allows for a quantitative description of the soft/hard transition, resulting in the correct Quantum-Chromodynamical asymptotics, including normalization, from the low-energy data without further parameter tuning. This happens universally whenever the constituent-quark mass is switched off. The energy range where the transition happens is therefore determined by the quark-mass running at intermediate energies and is not tightly constrained theoretically. Here we consider possible ways to pin down this energy range with coming experimental data. We demonstrate that expected experimental uncertainties of the 12-GeV Jefferson-Lab data are larger than the span of predictions of the model, so these data might be used for testing the model but not for determination of the soft/hard transition scale. Contrary, the projected Electron-Ion Colli...

  16. Recent advances in laser cooling of solids

    NASA Astrophysics Data System (ADS)

    Nemova, Galina; Kashyap, Raman

    2013-10-01

    The recent achievements devoted to cooling of solids with a laser are presented in this paper. We discuss the latest results of traditional laser cooling of solids based on rare earth ions and new techniques based on colloidal lead-salt quantum dots doped in a glass host, laser cooling in Tm3+-doped oxy-fluoride glass ceramic. Relatively short (microsecond) lifetime of the excited level of the PbSe QDs compared to the millisecond lifetime of the excited level of RE ions allows an acceleration of the cooling process and provides an opportunity to use new materials with higher phonon energy as hosts, which are normally considered unsuitable for cooling with RE ions. Another new approach to the laser cooling problem based on super-radiance has been considered in this paper. The advantages of optical refrigeration with rare earth doped semiconductors, in which not only optically active electrons of the 4f shell but the valence and conduction bands of the host material are involved in cooling cycle is discussed. It is shown that involving the valence and conduction bands of the host in the cooling cycle allows the pump wavelength to be shorter than mean fluorescence wavelength. Raman laser cooling of solids as well as observation of spontaneous Brillouin cooling have been presented.

  17. Electromagnetic Observables in Few-Nucleon Systems

    E-print Network

    Sonia Bacca

    2012-10-10

    The electromagnetic probe is a very valuable tool to study the dynamics of few nucleons. It can be very helpful in shedding light on the not yet fully understood three-nucleon forces. We present an update on the theoretical studies of electromagnetic induced reactions, such as photo-disintegration and electron scattering off 4He. We will show that they potentially represent a tool to discriminate among three-nucleon forces. Then, we will discuss the charge radius and the nuclear electric polarizability of the 6He halo nucleus.

  18. Piston cooling nozzle

    SciTech Connect

    Lee, T.R.

    1990-12-25

    This patent describes an assembly for cooling a piston in an internal combustion engine. It works by directing a spray of cooling fluid from the engine cooling fluid supply to a portion of the piston selected to achieve the optimum cooling of the entire piston.

  19. The state of the art in hadron beam cooling

    SciTech Connect

    Prost, L.R.; Derwent, P.; /Fermilab

    2008-09-01

    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 Laboratory's RHIC facility represent two recent major accomplishments. Novel ideas in the field will also be introduced.

  20. Electromagnetic Calorimeter for Hades Experiment

    NASA Astrophysics Data System (ADS)

    Kugler, A.; Blume, C.; Czyžycki, W.; Epple, E.; Fabbietti, L.; Galatyuk, T.; Golubeva, M.; Guber, F.; Hlavá?, S.; Ivashkin, A.; Kajetanowic, M.; Kardan, B.; Koenig, W.; Lapidus, K.; Lisowski, E.; Pietraszko, J.; Reshetin, A.; Rost, A.; Salabura, P.; Sobolev, Y. G.; Svoboda, O.; Tlusty, P.; Traxler, M.

    2014-06-01

    Electromagnetic calorimeter (ECAL) is being developed to complement the dilepton spectrometer HADES currently operating at GSI Darmstadt, Germany. ECAL will enable the HADES@FAIR experiment to measure data on neutral meson production in heavy ion collisions at the energy range of 2-10 A GeV on the beam of future accelerator SIS100@FAIR. The calorimeter will also improve the electron-hadron separation and will as well be used for the detection of photons from strange resonances in elementary and heavy ion reactions. Calorimeter modules constructed of lead glass Cherenkov counter, photomultiplier, HV divider and optical fiber are described in the detail. Two prototypes of novel front-end electronics based on TRB3 are presented. A dedicated LED based system being developed to monitor the stability of the calorimeter during beamtime is introduced as well.