MedWorm: Physics

A 100 kV, 60 A solid state 4 kHz switching modulator for high power klystron driving

Review of Scientific Instruments — Wed, 22 May 2013 06:16:18 +0100

O. D. Cortazar, D. Ganuza, J. M. De La Fuente, M. Zulaika, A. Perez et al. A solid state high power modulator capable of delivering 120 kV and 60 A developed in collaboration with the JEMA Corporation, ESS Bilbao, and the SNS (ORNL) for driving high power klystrons is presented. Pulses with less than 10 [mu]s risetime and flatness under 0.1% are obtained with programmable ... [Rev. Sci. Instrum. 84, 054706 (2013)] published Tue May 21, 2013. (Source: Review of Scientific Instruments)

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High-frequency annular array with coaxial illumination for dual-modality ultrasonic and photoacoustic imaging

Review of Scientific Instruments — Wed, 22 May 2013 06:16:18 +0100

Erwan Filoux, Ashwin Sampathkumar, Parag V. Chitnis, Orlando Aristizabal, and Jeffrey A. Ketterling This paper presents a combined ultrasound and photoacoustic (PA) imaging (PAI) system used to obtain high-quality, co-registered images of mouse-embryo anatomy and vasculature. High-frequency ultrasound (HFU, >20 MHz) is utilized to obtain high-resolution anatomical images of small animals while PAI ... [Rev. Sci. Instrum. 84, 053705 (2013)] published Tue May 21, 2013. (Source: Review of Scientific Instruments)

Modification of tokamak edge plasma turbulence and transport by biasing and resonant helical magnetic field

Review of Scientific Instruments — Wed, 22 May 2013 06:16:18 +0100

Mansoureh Lafouti, Mahmood Ghoranneviss, Sakineh Meshkani, and Ahmad Salar Elahi In this paper, both Resonant Helical magnetic Field (RHF) and limiter biasing have been applied to the tokamak. We have investigated their effects on the turbulence and transport of the particles at the edge of the plasma. The biased limiter voltage has been fixed at 200 V and RHF has L = 2 and L = ... [Rev. Sci. Instrum. 84, 053504 (2013)] published Tue May 21, 2013. (Source: Review of Scientific Instruments)

Development of a fast scintillator based beam phase measurement system for compact superconducting cyclotrons

Review of Scientific Instruments — Wed, 22 May 2013 06:16:18 +0100

We report here the development of a phase measurement system and the measurements carried o ... [Rev. Sci. Instrum. 84, 053303 (2013)] published Tue May 21, 2013. (Source: Review of Scientific Instruments)

Apparatus for measuring Seebeck coefficient and electrical resistivity of small dimension samples using infrared microscope as temperature sensor

Review of Scientific Instruments — Wed, 22 May 2013 06:16:18 +0100

W. M. N. Wan Jaafar, J. E. Snyder, and Gao Min An apparatus for measuring the Seebeck coefficient (alpha) and electrical resistivity (rho) was designed to operate under an infrared microscope. A unique feature of this apparatus is its capability of measuring alpha and rho of small-dimension (sub-millimeter) samples without the need for microfabr ... [Rev. Sci. Instrum. 84, 054903 (2013)] published Mon May 20, 2013. (Source: Review of Scientific Instruments)

A testbed for wide-field, high-resolution, gigapixel-class cameras

Review of Scientific Instruments — Wed, 22 May 2013 06:16:18 +0100

David S. Kittle, Daniel L. Marks, Hui S. Son, Jungsang Kim, and David J. Brady The high resolution and wide field of view (FOV) of the AWARE (Advanced Wide FOV Architectures for Image Reconstruction and Exploitation) gigapixel class cameras present new challenges in calibration, mechanical testing, and optical performance evaluation. The AWARE system integrates an array of mic ... [Rev. Sci. Instrum. 84, 053107 (2013)] published Mon May 20, 2013. (Source: Review of Scientific Instruments)

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Integration of strain feedback and charge drive for high-performance of piezoelectric actuators

Review of Scientific Instruments — Wed, 22 May 2013 06:16:18 +0100

Jie Zhang, Liansheng Zhang, and Zhihua Feng This paper introduces a hybrid control method that combines strain feedback control and charge driver. Strain feedback control method has good stability at low frequencies but suffers from limited resolution at high frequencies. The charge driver provides good linearity at high frequencies but exhib ... [Rev. Sci. Instrum. 84, 054705 (2013)] published Fri May 17, 2013. (Source: Review of Scientific Instruments)

Development and application of an instrument for spatially resolved Seebeck coefficient measurements

Review of Scientific Instruments — Wed, 22 May 2013 06:16:18 +0100

Andriy Zakutayev, Frank J. Luciano, IV, Vincent P. Bollinger, Ajaya K. Sigdel, Paul F. Ndione et al. The Seebeck coefficient is a key indicator of the majority carrier type (electrons or holes) in a material. The recent trend toward the development of combinatorial materials research methods has necessitated the development of a new high-throughput approach to measuring the Seebeck coefficient at s ... [Rev. Sci. Instrum. 84, 053905 (2013)] published Fri May 17, 2013. (Source: Review of Scientific Instruments)

The near wake of a freely flying European starling

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

Adam J. Kirchhefer, Gregory A. Kopp, and Roi Gurka The wake of a freely flying European starling (Sturnus vulgaris) has been measured using high speed, time-resolved, particle image velocimetry, simultaneously with high speed cameras which imaged the bird. These have been used to generate vector maps that can be associated with the bird's location a ... [Phys. Fluids 25, 051902 (2013)] published Tue May 21, 2013. (Source: Physics of Fluids)

Spatial ordering due to hydrodynamic interactions between a pair of colliding drops in a confined shear

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

Kausik Sarkar and Rajesh Kumar Singh Pair-collision between viscous drops in a confined shear is simulated to show that the confinement alters the trajectories of the drops spatially ordering them at a finite separation in the center of the domain. In contrast to free shear where drops eventually adopt free streamlines with a finite cr ... [Phys. Fluids 25, 051702 (2013)] published Tue May 21, 2013. (Source: Physics of Fluids)

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The fastest drop climbing on a wet conical fibre

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

Er Qiang Li and Sigurdur T. Thoroddsen We use high-speed video imaging to study the capillary-driven motion of a micro-droplet along the outside of a pre-wetted conical fiber. The cones are fabricated on a glass-puller with tip diameters as small as 1 [mu]m, an order of magnitude smaller than in previous studies. The liquid is fed throug ... [Phys. Fluids 25, 052105 (2013)] published Tue May 21, 2013. (Source: Physics of Fluids)

Vortex-shedding suppression in two-dimensional mixed convective flows past circular and square cylinders

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

Nadeem Hasan and Rashid Ali Vortex-shedding suppression in two-dimensional mixed convective flows past circular and square cylinders is investigated numerically at two supercritical Reynolds numbers, Re = 60 and 100, at a fixed Prandtl (Pr) number of 0.71. The Richardson number (Ri) and free-stream orientation (alpha) are vari ... [Phys. Fluids 25, 053603 (2013)] published Tue May 21, 2013. (Source: Physics of Fluids)

Spontaneous penetration of a non-wetting drop into an exposed pore

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

Pengtao Yue and Yuriko Renardy We consider the penetration process of a liquid drop approaching an exposed pore along the axis of symmetry, which is intended to model the penetration of non-wetting drops into a porous medium. Inertia and gravity are neglected at the current stage. In addition to the penetration into a capillary t ... [Phys. Fluids 25, 052104 (2013)] published Tue May 21, 2013. (Source: Physics of Fluids)

Travelling-wave similarity solutions for a steadily translating slender dry patch in a thin fluid film

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

Y. M. Yatim, B. R. Duffy, and S. K. Wilson A novel family of three-dimensional travelling-wave similarity solutions describing a steadily translating slender dry patch in an infinitely wide thin fluid film on an inclined planar substrate when surface-tension effects are negligible is obtained, the flow being driven by gravity and/or a prescr ... [Phys. Fluids 25, 052103 (2013)] published Tue May 21, 2013. (Source: Physics of Fluids)

Collisional radiative coarse-grain model for ionization in air

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

We present a reduced kinetic mechanism for the modeling of the behavior of the electronic states of the atomic species in air mixtures. The model is built by lumping the electronically excited states of the atomic species and by performing Maxwell-Boltzmann averages of the rate constants describing ... [Phys. Fluids 25, 057101 (2013)] published Tue May 21, 2013. (Source: Physics of Fluids)

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Intensified and attenuated waves in a microbubble TaylorCouette flow

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

T. Watamura, Y. Tasaka, and Y. Murai The effect of the presence of microbubbles on a flow state is experimentally investigated in a TaylorCouette flow with azimuthal waves, in order to examine the interaction mechanism of bubbles and flows that result in drag reduction. The average diameter of the bubbles is 60 [mu]m, which is smaller ... [Phys. Fluids 25, 054107 (2013)] published Mon May 20, 2013. (Source: Physics of Fluids)

Feedback control of instabilities in the two-dimensional Blasius boundary layer: The role of sensors and actuators

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

Brandt A. Belson, Onofrio Semeraro, Clarence W. Rowley, and Dan S. Henningson We analyze the effects of different types and positions of actuators and sensors on controllers' performance and robustness in the linearized 2D Blasius boundary layer. The investigation is carried out using direct numerical simulations (DNS). To facilitate controller design, we find reduced-order m ... [Phys. Fluids 25, 054106 (2013)] published Mon May 20, 2013. (Source: Physics of Fluids)

A self-adjusting flow dependent formulation for the classical Smagorinsky model coefficient

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

G. Ghorbaniasl, V. Agnihotri, and C. Lacor In this paper, we propose an efficient formula for estimating the model coefficient of a Smagorinsky model based subgrid scale eddy viscosity. The method allows vanishing eddy viscosity through a vanishing model coefficient in regions where the eddy viscosity should be zero. The advantage of this me ... [Phys. Fluids 25, 055102 (2013)] published Mon May 20, 2013. (Source: Physics of Fluids)

Vibrational convective instability of a binary electrolyte layer between plane horizontal electrodes

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

V. M. Volgin and A. D. Davydov The stability of a mechanical quasi-equilibrium state of a binary electrolyte layer between planar horizontal electrodes subjected to high-frequency vibration is studied theoretically. It is assumed that reversible anodic metal dissolution and cathodic reactions proceed at the layer boundaries (meta ... [Phys. Fluids 25, 054105 (2013)] published Mon May 20, 2013. (Source: Physics of Fluids)

Peregrine breather revisited

Physics of Fluids — Wed, 22 May 2013 06:16:17 +0100

L. Shemer and L. Alperovich Results of experiments on the evolution of the Peregrine breather (PB) in a wave tank are presented and compared with numerical simulations based on the Nonlinear Schrodinger (NLS) and the Dysthe equations. The experiments demonstrate notable deviation from the NLS solution due to significant asymme ... [Phys. Fluids 25, 051701 (2013)] published Mon May 20, 2013. (Source: Physics of Fluids)

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

Physics of Plasmas — Wed, 22 May 2013 06:16:17 +0100

Ya. N. Istomin and T. B. Leyser Plasma experiments in which a powerful electromagnetic pump wave is transmitted into the ionosphere from the ground give access to a rich range of phenomena, including gyroharmonic effects when the pump frequency is near an harmonic of the ionospheric electron gyrofrequency. For pump frequencies clo ... [Phys. Plasmas 20, 052904 (2013)] published Tue May 21, 2013. (Source: Physics of Plasmas)

Excitation of transverse dipole and quadrupole modes in a pure ion plasma in a linear Paul trap to study collective processes in intense beams

Physics of Plasmas — Wed, 22 May 2013 06:16:17 +0100

Erik P. Gilson, Ronald C. Davidson, Philip C. Efthimion, Richard Majeski, Edward A. Startsev et al. Transverse dipole and quadrupole modes have been excited in a one-component cesium ion plasma trapped in the Paul Trap Simulator Experiment (PTSX) in order to characterize their properties and understand the effect of their excitation on equivalent long-distance beam propagation. The PTSX device is ... [Phys. Plasmas 20, 055706 (2013)] published Tue May 21, 2013. (Source: Physics of Plasmas)

Fast ignition: Dependence of the ignition energy on source and target parameters for particle-in-cell-modelled energy and angular distributions of the fast electrons

Physics of Plasmas — Wed, 22 May 2013 06:16:17 +0100

C. Bellei, L. Divol, A. J. Kemp, M. H. Key, D. J. Larson et al. The energy and angular distributions of the fast electrons predicted by particle-in-cell (PIC) simulations differ from those historically assumed in ignition designs of the fast ignition scheme. Using a particular 3D PIC calculation, we show how the ignition energy varies as a function of source-fue ... [Phys. Plasmas 20, 052704 (2013)] published Tue May 21, 2013. (Source: Physics of Plasmas)

Laser produced plasma sources for nanolithographyRecent integrated simulation and benchmarking

Physics of Plasmas — Wed, 22 May 2013 06:16:17 +0100

A. Hassanein and T. Sizyuk Photon sources for extreme ultraviolet lithography (EUVL) are still facing challenging problems to achieve high volume manufacturing in the semiconductor industry. The requirements for high EUV power, longer optical system and components lifetime, and efficient mechanisms for target delivery have na ... [Phys. Plasmas 20, 053105 (2013)] published Tue May 21, 2013. (Source: Physics of Plasmas)

Radiative shocks produced from spherical cryogenic implosions at the National Ignition Facility

Physics of Plasmas — Wed, 22 May 2013 06:16:17 +0100

A. Pak, L. Divol, G. Gregori, S. Weber, J. Atherton et al. Spherically expanding radiative shock waves have been observed from inertially confined implosion experiments at the National Ignition Facility. In these experiments, a spherical fusion target, initially 2 mm in diameter, is compressed via the pressure induced from the ablation of the outer target s ... [Phys. Plasmas 20, 056315 (2013)] published Mon May 20, 2013. (Source: Physics of Plasmas)

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Resistive instability in a Hall plasma discharge under ionization effect

Physics of Plasmas — Wed, 22 May 2013 06:16:17 +0100

Hitendra K. Malik and Sukhmander Singh A systematic study is presented for low frequency resistive instability in a Hall plasma discharge under the effect of collisions, ionization, and finite temperature of ions and electrons by considering finite axial wave number. For this, a two dimensional dispersion equation is derived and solved n ... [Phys. Plasmas 20, 052115 (2013)] published Fri May 17, 2013. (Source: Physics of Plasmas)

Gyro-fluid and two-fluid theory and simulations of edge-localized-modes

Physics of Plasmas — Wed, 22 May 2013 06:16:17 +0100

X. Q. Xu, P. W. Xi, A. Dimits, I. Joseph, M. V. Umansky et al. This paper reports on the theoretical and simulation results of a gyro-Landau-fluid extension of the BOUT++ code, which contributes to increasing the physics understanding of edge-localized-modes (ELMs). Large ELMs with low-to-intermediate-n peeling-ballooning (P-B) modes are significantly suppresse ... [Phys. Plasmas 20, 056113 (2013)] published Fri May 17, 2013. (Source: Physics of Plasmas)

Comparisons of linear and nonlinear plasma response models for non-axisymmetric perturbations

Physics of Plasmas — Wed, 22 May 2013 06:16:17 +0100

A. D. Turnbull, N. M. Ferraro, V. A. Izzo, E. A. Lazarus, J.-K. Park et al. With the installation of non-axisymmetric coil systems on major tokamaks for the purpose of studying the prospects of ELM-free operation, understanding the plasma response to the applied fields is a crucial issue. Application of different response models, using standard tools, to DIII-D discharges w ... [Phys. Plasmas 20, 056114 (2013)] published Fri May 17, 2013. (Source: Physics of Plasmas)

Hohlraum energetics scaling to 520 TW on the National Ignition Facility

Physics of Plasmas — Wed, 22 May 2013 06:16:17 +0100

J. L. Kline, D. A. Callahan, S. H. Glenzer, N. B. Meezan, J. D. Moody et al. Indirect drive experiments have now been carried out with laser powers and energies up to 520 TW and 1.9 MJ. These experiments show that the energy coupling to the target is nearly constant at 84% 3% over a wide range of laser parameters from 350 to 520 TW and 1.2 to 1.9 MJ. Experiments at 520 TW w ... [Phys. Plasmas 20, 056314 (2013)] published Fri May 17, 2013. (Source: Physics of Plasmas)

Ponderomotive force on solitary structures created during radiation pressure acceleration of thin foils

Physics of Plasmas — Wed, 22 May 2013 06:16:17 +0100

Vipin K. Tripathi and Anamika Sharma We estimate the ponderomotive force on an expanded inhomogeneous electron density profile, created in the later phase of laser irradiated diamond like ultrathin foil. When ions are uniformly distributed along the plasma slab and electron density obeys the Poisson's equation with space charge potenti ... [Phys. Plasmas 20, 053104 (2013)] published Fri May 17, 2013. (Source: Physics of Plasmas)

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Laser ablated copper plasmas in liquid and gas ambient

Physics of Plasmas — Wed, 22 May 2013 06:16:17 +0100

Bhupesh Kumar and Raj K. Thareja The dynamics of copper ablated plasma plumes generated using laser ablation of copper targets in both liquid (de-ionized water) and gas (air) ambients is reported. Using time and space resolved visible emission spectroscopy (450-650 nm), the plasma plumes parameters are investigated. The electron de ... [Phys. Plasmas 20, 053503 (2013)] published Fri May 17, 2013. (Source: Physics of Plasmas)

Weak solutions for the Navier-Stokes equations with B+B+L initial data

Journal of Mathematical Physics — Wed, 22 May 2013 06:16:16 +0100

Shangbin Cui One of the major topics in the study of nonlinear partial differential equations of the evolutionary type is to look for as large as possible initial value spaces so that as many as possible solutions of such equations can be obtained. In the book Recent Developments in the Navier-Stokes Problems, L ... [J. Math. Phys. 54, 051503 (2013)] published Tue May 21, 2013. (Source: Journal of Mathematical Physics)

Quantum logarithmic Sobolev inequalities and rapid mixing

Journal of Mathematical Physics — Wed, 22 May 2013 06:16:16 +0100

Michael J. Kastoryano and Kristan Temme A family of logarithmic Sobolev inequalities on finite dimensional quantum state spaces is introduced. The framework of non-commutative [openface L]-spaces is reviewed and the relationship between quantum logarithmic Sobolev inequalities and the hypercontractivity of quantum semigroups is discussed. ... [J. Math. Phys. 54, 052202 (2013)] published Tue May 21, 2013. (Source: Journal of Mathematical Physics)

Spinors and the Weyl tensor classification in six dimensions

Journal of Mathematical Physics — Wed, 22 May 2013 06:16:16 +0100

Carlos Batista and Bruno Carneiro da Cunha A spinorial approach to six-dimensional differential geometry is constructed and used to analyze tensor fields of low rank, with special attention to the Weyl tensor. We perform a study similar to the four-dimensional case, making full use of the SO(6) symmetry to uncover results not easily seen in ... [J. Math. Phys. 54, 052502 (2013)] published Tue May 21, 2013. (Source: Journal of Mathematical Physics)

Supersymmetry algebra cohomology. IV. Primitive elements in all dimensions from D = 4 to D = 11

Journal of Mathematical Physics — Wed, 22 May 2013 06:16:16 +0100

Friedemann Brandt The primitive elements of the supersymmetry algebra cohomology as defined in previous work are derived for standard supersymmetry algebras in dimensions D = 5, …, 11 for all signatures of the related Clifford algebras of gamma matrices and all numbers of supersymmetries. The results are prese ... [J. Math. Phys. 54, 052302 (2013)] published Mon May 20, 2013. (Source: Journal of Mathematical Physics)

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Baker-Akhiezer functions and generalised Macdonald-Mehta integrals

Journal of Mathematical Physics — Wed, 22 May 2013 06:16:16 +0100

M. V. Feigin, M. A. Hallnas, and A. P. Veselov For the rational Baker-Akhiezer functions associated with special arrangements of hyperplanes with multiplicities we establish an integral identity, which may be viewed as a generalisation of the self-duality property of the usual Gaussian function with respect to the Fourier transformation. We show ... [J. Math. Phys. 54, 052106 (2013)] published Mon May 20, 2013. (Source: Journal of Mathematical Physics)

On the relationship between the classical Dicke-Jaynes-Cummings-Gaudin model and the nonlinear Schrodinger equation

Journal of Mathematical Physics — Wed, 22 May 2013 06:16:16 +0100

Dianlou Du and Xue Geng In this paper, the relationship between the classical Dicke-Jaynes-Cummings-Gaudin (DJCG) model and the nonlinear Schrodinger (NLS) equation is studied. It is shown that the classical DJCG model is equivalent to a stationary NLS equation. Moreover, the standard NLS equation can be solved by the clas ... [J. Math. Phys. 54, 053510 (2013)] published Fri May 17, 2013. (Source: Journal of Mathematical Physics)

The two dimensional motion of a particle in an inverse square potential: Classical and quantum aspects

Journal of Mathematical Physics — Wed, 22 May 2013 06:16:16 +0100

R. P. Martinez-y-Romero, H. N. Nunez-Yepez, and A. L. Salas-Brito The classical 2D dynamics of a particle moving under an inverse square potential, k/r, is analysed. We show that such problem is an example of a geometric system since its negative energy orbits are equivalent to free motion on a certain hypersurface. We then solve in momentum space, the correspondi ... [J. Math. Phys. 54, 053509 (2013)] published Fri May 17, 2013. (Source: Journal of Mathematical Physics)

Assessment of range-separated time-dependent density-functional theory for calculating C dispersion coefficients