Wave-particle interactions in rotating mirrorsa)
Fetterman, Abraham J.; Fisch, Nathaniel J.
2011-05-01
Wave-particle interactions in E ×B rotating plasmas feature an unusual effect: particles are diffused by waves in both potential energy and kinetic energy. This wave-particle interaction generalizes the alpha channeling effect, in which radio frequency waves are used to remove alpha particles collisionlessly at low energy. In rotating plasmas, the alpha particles may be removed at low energy through the loss cone, and the energy lost may be transferred to the radial electric field. This eliminates the need for electrodes in the mirror throat, which have presented serious technical issues in past rotating plasma devices. A particularly simple way to achieve this effect is to use a high azimuthal mode number perturbation on the magnetic field. Rotation can also be sustained by waves in plasmas without a kinetic energy source. This type of wave has been considered for plasma centrifuges used for isotope separation. Energy may also be transferred from the electric field to particles or waves, which may be useful for ion heating and energy generation.
Wave-particle Interactions In Rotating Mirrors
Energy Technology Data Exchange (ETDEWEB)
Abraham J. Fetterman and Nathaniel J. Fisch
2011-01-11
Wave-particle interactions in E×B rotating plasmas feature an unusual effect: particles are diffused by waves in both potential energy and kinetic energy. This wave-particle interaction generalizes the alpha channeling effect, in which radio frequency waves are used to remove alpha particles collisionlessly at low energy. In rotating plasmas, the alpha particles may be removed at low energy through the loss cone, and the energy lost may be transferred to the radial electric field. This eliminates the need for electrodes in the mirror throat, which have presented serious technical issues in past rotating plasma devices. A particularly simple way to achieve this effect is to use a high azimuthal mode number perturbation on the magnetic field. Rotation can also be sustained by waves in plasmas without a kinetic energy source. This type of wave has been considered for plasma centrifuges used for isotope separation. Energy may also be transferred from the electric field to particles or waves, which may be useful for ion heating and energy generation.
Wave-particle interactions in rotating mirrors
International Nuclear Information System (INIS)
Fetterman, Abraham J.; Fisch, Nathaniel J.
2011-01-01
Wave-particle interactions in ExB rotating plasmas feature an unusual effect: particles are diffused by waves in both potential energy and kinetic energy. This wave-particle interaction generalizes the alpha channeling effect, in which radio frequency waves are used to remove alpha particles collisionlessly at low energy. In rotating plasmas, the alpha particles may be removed at low energy through the loss cone, and the energy lost may be transferred to the radial electric field. This eliminates the need for electrodes in the mirror throat, which have presented serious technical issues in past rotating plasma devices. A particularly simple way to achieve this effect is to use a high azimuthal mode number perturbation on the magnetic field. Rotation can also be sustained by waves in plasmas without a kinetic energy source. This type of wave has been considered for plasma centrifuges used for isotope separation. Energy may also be transferred from the electric field to particles or waves, which may be useful for ion heating and energy generation.
Wave-particle Interactions In Rotating Mirrors
International Nuclear Information System (INIS)
Fetterman, Abraham J.; Fisch, Nathaniel J.
2011-01-01
Wave-particle interactions in E-B rotating plasmas feature an unusual effect: particles are diffused by waves in both potential energy and kinetic energy. This wave-particle interaction generalizes the alpha channeling effect, in which radio frequency waves are used to remove alpha particles collisionlessly at low energy. In rotating plasmas, the alpha particles may be removed at low energy through the loss cone, and the energy lost may be transferred to the radial electric field. This eliminates the need for electrodes in the mirror throat, which have presented serious technical issues in past rotating plasma devices. A particularly simple way to achieve this effect is to use a high azimuthal mode number perturbation on the magnetic field. Rotation can also be sustained by waves in plasmas without a kinetic energy source. This type of wave has been considered for plasma centrifuges used for isotope separation. Energy may also be transferred from the electric field to particles or waves, which may be useful for ion heating and energy generation.
Wave-particle interaction in the Faraday waves.
Francois, N; Xia, H; Punzmann, H; Shats, M
2015-10-01
Wave motion in disordered Faraday waves is analysed in terms of oscillons or quasi-particles. The motion of these oscillons is measured using particle tracking tools and it is compared with the motion of fluid particles on the water surface. Both the real floating particles and the oscillons, representing the collective fluid motion, show Brownian-type dispersion exhibiting ballistic and diffusive mean squared displacement at short and long times, respectively. While the floating particles motion has been previously explained in the context of two-dimensional turbulence driven by Faraday waves, no theoretical description exists for the random walk type motion of oscillons. It is found that the r.m.s velocity ⟨μ̃(osc)⟩(rms) of oscillons is directly related to the turbulent r.m.s. velocity ⟨μ̃⟩(rms) of the fluid particles in a broad range of vertical accelerations. The measured ⟨μ̃(osc)⟩(rms) accurately explains the broadening of the frequency spectra of the surface elevation observed in disordered Faraday waves. These results suggest that 2D turbulence is the driving force behind both the randomization of the oscillons motion and the resulting broadening of the wave frequency spectra. The coupling between wave motion and hydrodynamic turbulence demonstrated here offers new perspectives for predicting complex fluid transport from the knowledge of wave field spectra and vice versa.
Wave-particle Interactions in Space and Laboratory Plasmas
An, Xin
This dissertation presents a study of wave-particle interactions in space and in the laboratory. To be concrete, the excitation of whistler-mode chorus waves in space and in the laboratory is studied in the first part. The relaxation of whistler anisotropy instability relevant to whistler-mode chorus waves in space is examined. Using a linear growth rate analysis and kinetic particle-in-cell simulations, the electron distributions are demonstrated to be well-constrained by the whistler anisotropy instability to a marginal-stability state, consistent with measurements by Van Allen Probes. The electron parallel beta beta ∥e separates the excited whistler waves into two groups: (i) quasi-parallel whistler waves for beta∥e > 0.02 and (ii) oblique whistler waves close to the resonance cone for beta∥e cell simulations. Motivated by the puzzles of chorus waves in space and by their recognized importance, the excitation of whistler-mode chorus waves is studied in the Large Plasma Device by the injection of a helical electron beam into a cold plasma. Incoherent broadband whistler waves similar to magnetospheric hiss are observed in the laboratory plasma. Their mode structures are identified by the phase-correlation technique. It is demonstrated that the waves are excited through a combination of Landau resonance, cyclotron resonance and anomalous cyclotron resonance. To account for the finite size effect of the electron beam, linear unstable eigenmodes of whistler waves are calculated by matching the eigenmode solution at the boundary. It is shown that the perpendicular wave number inside the beam is quantized due to the constraint imposed by the boundary condition. Darwin particle-in-cell simulations are carried out to study the simultaneous excitation of Langmuir and whistler waves in a beam-plasma system. The electron beam is first slowed down and relaxed by the rapidly growing Langmuir wave parallel to the background magnetic field. The tail of the core electrons
Nonlinear wave particle interaction in the Earth's foreshock
Mazelle, C.; LeQueau, D.; Meziane, K.; Lin, R. P.; Parks, G.; Reme, H.; Sanderson, T.; Lepping, R. P.
1997-01-01
The possibility that ion beams could provide a free energy source for driving an ion/ion instability responsible for the ULF wave occurrence is investigated. For this, the wave dispersion relation with the observed parameters is solved. Secondly, it is shown that the ring-like distributions could then be produced by a coherent nonlinear wave-particle interaction. It tends to trap the ions into narrow cells in velocity space centered around a well-defined pitch-angle, directly related to the saturation wave amplitude in the analytical theory. The theoretical predictions with the observations are compared.
Interaction for solitary waves in coasting charged particle beams
Energy Technology Data Exchange (ETDEWEB)
Liu, Shi-Wei; Hong, Xue-Ren; Shi, Yu-Ren; Duan, Wen-shan, E-mail: duanws@nwnu.edu.cn [College of Physics and Electronic Engineering and Joint Laboratory of Atomic an Molecular Physics of NWNU and IMPCAS, Northwest Normal University, Lanzhou 730070 (China); Qi, Xin; Yang, Lei, E-mail: lyang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Han, Jiu-Ning [College of Physics and Electromechanical Engineering, Hexi University, Zhangye 734000 (China)
2014-03-15
By using the extended Poincare-Lighthill-Kuo perturbation method, the collision of solitary waves in a coasting charged particle beams is studied. The results show that the system admits a solution with two solitary waves, which move in opposite directions and can be described by two Korteweg-deVries equation in small-amplitude limit. The collision of two solitary waves is elastic, and after the interaction they preserve their original properties. Then the weak phase shift in traveling direction of collision between two solitary waves is derived explicitly.
Directory of Open Access Journals (Sweden)
B. T. Tsurutani
2002-04-01
Full Text Available Energetic particles and MHD waves are studied using simultaneous ISEE-3 data to investigate particle propagation and scattering between the source near the Sun and 1 AU. 3 He-rich events are of particular interest because they are typically low intensity "scatter-free" events. The largest solar proton events are of interest because they have been postulated to generate their own waves through beam instabilities. For 3 He-rich events, simultaneous interplanetary magnetic spectra are measured. The intensity of the interplanetary "fossil" turbulence through which the particles have traversed is found to be at the "quiet" to "intermediate" level of IMF activity. Pitch angle scattering rates and the corresponding particle mean free paths lW - P are calculated using the measured wave intensities, polarizations, and k directions. The values of lW - P are found to be ~ 5 times less than the value of lHe , the latter derived from He intensity and anisotropy time profiles. It is demonstrated by computer simulation that scattering rates through a 90° pitch angle are lower than that of other pitch angles, and that this is a possible explanation for the discrepancy between the lW - P and lHe values. At this time the scattering mechanism(s is unknown. We suggest a means where a direct comparison between the two l values could be made. Computer simulations indicate that although scattering through 90° is lower, it still occurs. Possibilities are either large pitch angle scattering through resonant interactions, or particle mirroring off of field compression regions. The largest solar proton events are analyzed to investigate the possibilities of local wave generation at 1 AU. In accordance with the results of a previous calculation (Gary et al., 1985 of beam stability, proton beams at 1 AU are found to be marginally stable. No evidence for substantial wave amplitude was found. Locally generated waves, if present, were less than 10-3 nT 2 Hz-1 at the leading
Directory of Open Access Journals (Sweden)
T. Hada
Full Text Available Energetic particles and MHD waves are studied using simultaneous ISEE-3 data to investigate particle propagation and scattering between the source near the Sun and 1 AU. 3 He-rich events are of particular interest because they are typically low intensity "scatter-free" events. The largest solar proton events are of interest because they have been postulated to generate their own waves through beam instabilities. For 3 He-rich events, simultaneous interplanetary magnetic spectra are measured. The intensity of the interplanetary "fossil" turbulence through which the particles have traversed is found to be at the "quiet" to "intermediate" level of IMF activity. Pitch angle scattering rates and the corresponding particle mean free paths lW - P are calculated using the measured wave intensities, polarizations, and k directions. The values of lW - P are found to be ~ 5 times less than the value of lHe , the latter derived from He intensity and anisotropy time profiles. It is demonstrated by computer simulation that scattering rates through a 90° pitch angle are lower than that of other pitch angles, and that this is a possible explanation for the discrepancy between the lW - P and lHe values. At this time the scattering mechanism(s is unknown. We suggest a means where a direct comparison between the two l values could be made. Computer simulations indicate that although scattering through 90° is lower, it still occurs. Possibilities are either large pitch angle scattering through resonant interactions, or particle mirroring off of field compression regions. The largest solar proton events are analyzed to investigate the possibilities of local wave generation at 1 AU. In accordance with the results of a previous calculation (Gary et al., 1985 of beam stability, proton beams at 1 AU are found to be marginally stable. No evidence for substantial wave amplitude was found. Locally generated waves, if present, were less than 10-3 nT 2 Hz-1 at the leading
Particle Dynamics under Quasi-linear Interaction with Electromagnetic Waves
Energy Technology Data Exchange (ETDEWEB)
Castejon, F.; Eguilior, S.
2003-07-01
Langevin equations for quasi-linear wave particle interaction are obtained taking advantage of the unique vocal equivalence between Fokker-Plank equation and the former ones. Langevin equations are solved numerically and, hence, the evolution of a single particle embedded in an electromagnetic field in momentum space is obtained. The equations are relativistic and valid for any wave. It is also shown that the stochastic part of the equations is negligible in comparison with the deterministic term, except for the momentum to the resonance condition for the main parallel refractive index. (Author) 24 refs.
Particle Dynamics under Quasi-linear Interaction with Electromagnetic Waves
International Nuclear Information System (INIS)
Castejon, F.; Eguilior, S.
2003-01-01
Langevin equations for quasi-linear wave particle interaction are obtained taking advantage of the unique vocal equivalence between Fokker-Plank equation and the former ones. Langevin equations are solved numerically and, hence, the evolution of a single particle embedded in an electromagnetic field in momentum space is obtained. The equations are relativistic and valid for any wave. It is also shown that the stochastic part of the equations is negligible in comparison with the deterministic term, except for the momentum to the resonance condition for the main parallel refractive index. (Author) 24 refs
Computational and theoretical study of the wave-particle interaction of protons and waves
Directory of Open Access Journals (Sweden)
P. S. Moya
2012-09-01
Full Text Available We study the wave-particle interaction and the evolution of electromagnetic waves propagating through a plasma composed of electrons and protons, using two approaches. First, a quasilinear kinetic theory has been developed to study the energy transfer between waves and particles, with the subsequent acceleration and heating of protons. Second, a one-dimensional hybrid numerical simulation has been performed, with and without including an expanding-box model that emulates the spherical expansion of the solar wind, to investigate the fully nonlinear evolution of this wave-particle interaction. Numerical results of both approaches show that there is an anisotropic evolution of proton temperature.
Simulations of Shock Wave Interaction with a Particle Cloud
Koneru, Rahul; Rollin, Bertrand; Ouellet, Frederick; Annamalai, Subramanian; Balachandar, S.'Bala'
2016-11-01
Simulations of a shock wave interacting with a cloud of particles are performed in an attempt to understand similar phenomena observed in dispersal of solid particles under such extreme environment as an explosion. We conduct numerical experiments in which a particle curtain fills only 87% of the shock tube from bottom to top. As such, the particle curtain upon interaction with the shock wave is expected to experience Kelvin-Helmholtz (KH) and Richtmyer-Meshkov (RM) instabilities. In this study, the initial volume fraction profile matches with that of Sandia Multiphase Shock Tube experiments, and the shock Mach number is limited to M =1.66. In these simulations we use a Eulerian-Lagrangian approach along with state-of-the-art point-particle force and heat transfer models. Measurements of particle dispersion are made at different initial volume fractions of the particle cloud. A detailed analysis of the evolution of the particle curtain with respect to the initial conditions is presented. This work was supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, Contract No. DE-NA0002378.
Wave--particle interactions in the magnetosphere and ionosphere
International Nuclear Information System (INIS)
Thorne, R.M.
1975-01-01
Two distinct aspects of the interaction between waves and particles in the earth's magnetosphere and ionosphere were discussed at the Yosemite Conference on Magnetosphere-Ionosphere Coupling; these will be briefly reviewed. Intense field-aligned currents flow between the ionosphere and magnetosphere at auroral latitudes. Under certain conditions these currents can become unstable, permitting potential drops to be established along the field lines. The present status of experimental evidence favoring such parallel electric fields is somewhat controversial. Theoretical models for their origin invoke regions of anomalous resistivity or electrostatic double layers. To date it is impossible to distinguish between these alternatives on the basis of experimental data. The nonadiabatic behavior of magnetospheric ring current particles during geomagnetic storms is largely controlled by wave-particle processes. During the storm main phase, intense fluctuating convection electric fields are responsible for injecting trapped particles into the outer radiation zone. The outer radiation zone also moves in closer to the earth following the storm time compression of the plasmapause. Simultaneous pitch angle scattering by higher-frequency plasma turbulence causes precipitation loss near the strong diffusion limit throughout the outer magnetosphere. During the storm recov []ry phase the plasmapause slowly moves out toward its prestorm location; energetic particle loss at such times appears to be dominated by cyclotron resonant scattering from electromagnetic turbulence. (auth)
Wave-particle interaction and Hamiltonian dynamics investigated in a traveling wave tube
International Nuclear Information System (INIS)
Doveil, Fabrice; Macor, Alessandro
2006-01-01
For wave-particle interaction studies, the one-dimensional (1-D) beam-plasma system can be advantageously replaced by a Traveling Wave Tube (TWT). This led us to a detailed experimental analysis of the self-consistent interaction between unstable waves and a small either cold or warm beam. More recently, a test electron beam has been used to observe its non-self-consistent interaction with externally excited wave(s). The velocity distribution function of the electron beam is investigated with a trochoidal energy analyzer that records the beam energy distribution at the output of the TWT. An arbitrary waveform generator is used to launch a prescribed spectrum of waves along the slow wave structure (a 4 m long helix) of the TWT. The nonlinear synchronization of particles by a single wave responsible for Landau damping is observed. The resonant velocity domain associated to a single wave is also observed, as well as the transition to large-scale chaos when the resonant domains of two waves and their secondary resonances overlap leading to a typical 'devil's staircase' behavior. A new strategy for the control of chaos is tested
Fast Particle Interaction With Waves In Fusion Plasmas
International Nuclear Information System (INIS)
Breizman, Boris
2006-01-01
There are two well-known motivations for theoretical studies of fast particle interaction with waves in magnetic confinement devices. One is the challenge of avoiding strong collective losses of alpha particles and beam ions in future burning plasma experiments. The other one is the compelling need to quantitatively interpret the large amount of experimental data from JET, TFTR, JT-60U, DIII-D, and other machines. Such interpretation involves unique diagnostic opportunities offered by MHD spectroscopy. This report discusses how the present theory responds to the stated challenges and what theoretical and computational advances are required to address the outstanding problems. More specifically, this paper deals with the following topics: predictive capabilities of linear theory and simulations; theory of Alfven cascades; diagnostic opportunities based on linear and nonlinear properties of unstable modes; interplay of kinetic and fluid nonlinearities; fast chirping phenomena for non-perturbative modes; and global transport of fast particles. Recent results are presented on some of the listed topics, although the main goal is to identify critical issues for future work
Wave-particle interaction phenomena observed by antarctic rockets
International Nuclear Information System (INIS)
Kimura, I.; Hirasawa, T.
1979-01-01
Rocket measurements of wave and particles activities made at Syowa Station in Antarctica during IMS period are reviewed. Nine rockets were used for such observations, out of which 6 rockets were launched in the auroral sky. In the VLF frequency range, 0 - 10 KHz, wideband spectra of wave electric and magnetic fields, Poynting flux and the direction of propagation vector were measured for chorus, ELF and VLF hiss, and for electrostatic noises. In the MF and HF range, the dynamic frequency spectra of 0.1 - 10 MHz were measured. The relationship of these wave phenomena with energetic particle activities measured by the same rockets are discussed. (author)
Velocity width of the resonant domain in wave-particle interaction
International Nuclear Information System (INIS)
Firpo, Marie-Christine; Doveil, Fabrice
2002-01-01
Wave-particle interaction is a ubiquitous physical mechanism exhibiting locality in velocity space. A single-wave Hamiltonian provides a rich model by which to study the self-consistent interaction between one electrostatic wave and N quasiresonant particles. For the simplest nonintegrable Hamiltonian coupling two particles to one wave, we analytically derive the particle velocity borders separating quasi-integrable motions from chaotic ones. These estimates are fully retrieved through computation of the largest Lyapunov exponent. For the large-N particle self-consistent case, we numerically investigate the localization of stochasticity in velocity space and test a qualitative estimate of the borders of chaos
Electron Climbing a 'Devil's Staircase' in Wave-Particle Interaction
International Nuclear Information System (INIS)
Macor, Alessandro; Doveil, Fabrice; Elskens, Yves
2005-01-01
Numerous nonlinear driven systems display spectacular responses to forcing, including chaos and complex phase-locking plateaus characterized by 'devil's staircase', Arnold tongues, and Farey trees. In the universality class of Hamiltonian systems, a paradigm is the motion of a charged particle in two waves, which inspired a renormalization group method for its description. Here we report the observation of the underlying 'devil's staircase' by recording the beam velocity distribution function at the outlet of a traveling wave tube versus the amplitude of two externally induced waves
Advanced Accelerators: Particle, Photon and Plasma Wave Interactions
Energy Technology Data Exchange (ETDEWEB)
Williams, Ronald L. [Florida A & M University, Tallahassee, FL (United States)
2017-06-29
The overall objective of this project was to study the acceleration of electrons to very high energies over very short distances based on trapping slowly moving electrons in the fast moving potential wells of large amplitude plasma waves, which have relativistic phase velocities. These relativistic plasma waves, or wakefields, are the basis of table-top accelerators that have been shown to accelerate electrons to the same high energies as kilometer-length linear particle colliders operating using traditional decades-old acceleration techniques. The accelerating electrostatic fields of the relativistic plasma wave accelerators can be as large as GigaVolts/meter, and our goal was to study techniques for remotely measuring these large fields by injecting low energy probe electron beams across the plasma wave and measuring the beam’s deflection. Our method of study was via computer simulations, and these results suggested that the deflection of the probe electron beam was directly proportional to the amplitude of the plasma wave. This is the basis of a proposed diagnostic technique, and numerous studies were performed to determine the effects of changing the electron beam, plasma wave and laser beam parameters. Further simulation studies included copropagating laser beams with the relativistic plasma waves. New interesting results came out of these studies including the prediction that very small scale electron beam bunching occurs, and an anomalous line focusing of the electron beam occurs under certain conditions. These studies were summarized in the dissertation of a graduate student who obtained the Ph.D. in physics. This past research program has motivated ideas for further research to corroborate these results using particle-in-cell simulation tools which will help design a test-of-concept experiment in our laboratory and a scaled up version for testing at a major wakefield accelerator facility.
Eiichirou, Kawamori
2018-04-01
We report the observation of supercontinuum of Langmuir plasma waves, that exhibits broad power spectrum having significant spatio-temporal coherence grown from a monochromatic seed-wave, in one-dimensional particle-in-cell simulations. The Langmuir wave supercontinuum (LWSC) is formed when the seed wave excites side-band fields efficiently by the modulational instabilities. Its identification is achieved by the use of the tricoherence analysis, which detects four wave mixings (FWMs) of plasmons (plasma wave quanta), and evaluation of the first order coherence, which is a measure of temporal coherence, of the wave electric fields. The irreversible evolution to the coherent LWSC from the seed wave is realized by the wave-particle interactions causing stochastic electron motions in the phase space and the coherence of LWSC is maintained by the phase-preserving FWMs of plasmons. The LWSC corresponds to a quasi Bernstein-Greene-Kruskal mode.
Current generation by alpha particles interacting with lower hybrid waves in TOKAMAKS
International Nuclear Information System (INIS)
Belikov, V.S.; Kolesnichenko, Ya.I.; Lisak, M.; Anderson, D.
1990-01-01
The problem of the influence of fusion generated alpha particles on lower-hybrid-wave current drive is examined. Analysis is based on a new equation for the LH-wave-fast ion interaction which is derived by taking into consideration the non-zero value of the longitudinal wave number. The steady-state velocity distribution function for high energy alpha particles is found. The alpha current driven by LH-waves as well as the RF-power absorbed by alpha particle are calculated. (authors)
Huang, K.-N.
1977-01-01
A computational procedure for calculating correlated wave functions is proposed for three-particle systems interacting through Coulomb forces. Calculations are carried out for the muonic helium atom. Variational wave functions which explicitly contain interparticle coordinates are presented for the ground and excited states. General Hylleraas-type trial functions are used as the basis for the correlated wave functions. Excited-state energies of the muonic helium atom computed from 1- and 35-term wave functions are listed for four states.
Observation and Control of Hamiltonian Chaos in Wave-particle Interaction
International Nuclear Information System (INIS)
Doveil, F.; Ruzzon, A.; Elskens, Y.
2010-01-01
Wave-particle interactions are central in plasma physics. The paradigm beam-plasma system can be advantageously replaced by a traveling wave tube (TWT) to allow their study in a much less noisy environment. This led to detailed analysis of the self-consistent interaction between unstable waves and an either cold or warm electron beam. More recently a test cold beam has been used to observe its interaction with externally excited wave(s). This allowed observing the main features of Hamiltonian chaos and testing a new method to efficiently channel chaotic transport in phase space. To simulate accurately and efficiently the particle dynamics in the TWT and other 1D particle-wave systems, a new symplectic, symmetric, second order numerical algorithm is developed, using particle position as the independent variable, with a fixed spatial step.This contribution reviews: presentation of the TWT and its connection to plasma physics, resonant interaction of a charged particle in electrostatic waves, observation of particle trapping and transition to chaos, test of control of chaos, and description of the simulation algorithm.The velocity distribution function of the electron beam is recorded with a trochoidal energy analyzer at the output of the TWT. An arbitrary waveform generator is used to launch a prescribed spectrum of waves along the 4m long helix of the TWT. The nonlinear synchronization of particles by a single wave, responsible for Landau damping, is observed. We explore the resonant velocity domain associated with a single wave as well as the transition to large scale chaos when the resonant domains of two waves and their secondary resonances overlap. This transition exhibits a devil's staircase behavior when increasing the excitation level in agreement with numerical simulation.A new strategy for control of chaos by building barriers of transport in phase space as well as its robustness is successfully tested. The underlying concepts extend far beyond the field of
International Nuclear Information System (INIS)
Zhang, Shenwei; Qiu, Chunyin; Wang, Mudi; Ke, Manzhu; Liu, Zhengyou
2016-01-01
In this work, we study the acoustically mediated interaction forces among multiple well-separated spherical particles trapped in the same node or antinode plane of a standing wave. An analytical expression of the acoustic interaction force is derived, which is accurate even for the particles beyond the Rayleigh limit. Interestingly, the multi-particle system can be decomposed into a series of independent two-particle systems described by pairwise interactions. Each pairwise interaction is a long-range interaction, as characterized by a soft oscillatory attenuation (at the power exponent of n = −1 or −2). The vector additivity of the acoustic interaction force, which is not well expected considering the nonlinear nature of the acoustic radiation force, is greatly useful for exploring a system consisting of a large number of particles. The capability of self-organizing a big particle cluster can be anticipated through such acoustically controllable long-range interaction. (paper)
Data processing in Software-type Wave-Particle Interaction Analyzer onboard the Arase satellite
Hikishima, Mitsuru; Kojima, Hirotsugu; Katoh, Yuto; Kasahara, Yoshiya; Kasahara, Satoshi; Mitani, Takefumi; Higashio, Nana; Matsuoka, Ayako; Miyoshi, Yoshizumi; Asamura, Kazushi; Takashima, Takeshi; Yokota, Shoichiro; Kitahara, Masahiro; Matsuda, Shoya
2018-05-01
The software-type wave-particle interaction analyzer (S-WPIA) is an instrument package onboard the Arase satellite, which studies the magnetosphere. The S-WPIA represents a new method for directly observing wave-particle interactions onboard a spacecraft in a space plasma environment. The main objective of the S-WPIA is to quantitatively detect wave-particle interactions associated with whistler-mode chorus emissions and electrons over a wide energy range (from several keV to several MeV). The quantity of energy exchanges between waves and particles can be represented as the inner product of the wave electric-field vector and the particle velocity vector. The S-WPIA requires accurate measurement of the phase difference between wave and particle gyration. The leading edge of the S-WPIA system allows us to collect comprehensive information, including the detection time, energy, and incoming direction of individual particles and instantaneous-wave electric and magnetic fields, at a high sampling rate. All the collected particle and waveform data are stored in the onboard large-volume data storage. The S-WPIA executes calculations asynchronously using the collected electric and magnetic wave data, data acquired from multiple particle instruments, and ambient magnetic-field data. The S-WPIA has the role of handling large amounts of raw data that are dedicated to calculations of the S-WPIA. Then, the results are transferred to the ground station. This paper describes the design of the S-WPIA and its calculations in detail, as implemented onboard Arase.[Figure not available: see fulltext.
Observation of Hamiltonian chaos and its control in wave-particle interaction
International Nuclear Information System (INIS)
Doveil, F; Macor, A; Aissi, A
2007-01-01
Wave-particle interactions are central in plasma physics. They can be studied in a traveling wave tube (TWT) to avoid intrinsic plasma noise. This led to detailed experimental analysis of the self-consistent interaction between unstable waves and an either cold or warm beam. More recently a test cold electron beam has been used to observe its non-self-consistent interaction with externally excited wave(s). The velocity distribution function of the electron beam is recorded with a trochoidal energy analyzer at the output of the TWT. An arbitrary waveform generator is used to launch a prescribed spectrum of waves along the slow wave structure (a 4 m long helix) of the TWT. The nonlinear synchronization of particles by a single wave responsible for Landau damping is observed. The resonant velocity domain associated with a single wave is also observed, as well as the transition to large scale chaos when the resonant domains of two waves and their secondary resonances overlap. This transition exhibits a 'devil's staircase' behavior when increasing the excitation amplitude in agreement with numerical simulation. A new strategy for control of chaos by building barriers of transport which prevent electrons from escaping from a given velocity region as well as its robustness are successfully tested. The underlying concepts extend far beyond the field of electron devices and plasma physics
Reversible electron heating vs. wave-particle interactions in quasi-perpendicular shocks
Veltri, P.; Mangeney, A.; Scudder, J. D.
1992-01-01
The energy necessary to explain the electron heating in quasi-perpendicular collisionless shocks can be derived either from the electron acceleration in the d.c. cross shock electric potential, or by the interactions between the electrons and the waves existing in the shock. A Monte Carlo simulation has been performed to study the electron distribution function evolution through the shock structure, with and without particle diffusion on waves. This simulation has allowed us to clarify the relative importance of the two possible energy sources; in particular it has been shown that the electron parallel temperature is determined by the d.c. electromagnetic field and not by any wave-particle-induced heating. Wave particle interactions are effective in smoothing out the large gradients in phase space produced by the 'reversible' motion of the electrons, thus producing a 'cooling' of the electrons.
Theory of nonlinear interaction of particles and waves in an inverse plasma maser. Part 1
International Nuclear Information System (INIS)
Krivitsky, V.S.; Vladimirov, S.V.
1991-01-01
An expression is obtained for the collision integral describing the simultaneous interaction of plasma particles with resonant and non-resonant waves. It is shown that this collision integral is determined by two processes: a 'direct' nonlinear interaction of particles and waves, and the influence of the non-stationary of the system. The expression for the nonlinear collision integral is found to be quite different from the expression for a quasi-linear collision integral; in particular, the nonlinear integral contains higher-order derivatives of the distribution function with respect to momentum than the quasi-linear one. (author)
Stability analysis of a Vlasov-Wave system describing particles interacting with their environment
De Bièvre, Stephan; Goudon, Thierry; Vavasseur, Arthur
2018-06-01
We study a kinetic equation of the Vlasov-Wave type, which arises in the description of the behavior of a large number of particles interacting weakly with an environment, composed of an infinite collection of local vibrational degrees of freedom, modeled by wave equations. We use variational techniques to establish the existence of large families of stationary states for this system, and analyze their stability.
Two-Fluid Description of Wave-Particle Interactions in Strong Buneman Turbulence
Che, H.
2014-01-01
To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation while a plasma is unstable to the Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. We show that both energy dissipation and momentum tra...
The physics of wave-particle interactions with applications to astrophysics
International Nuclear Information System (INIS)
Karimabadi, H.
1988-01-01
The physics of electromagnetic wave-particle interactions in the limit of a strong static magnetic field is investigated using Hamiltonian and multiple time-scale techniques. For sufficiently small wave amplitude, the system is integrable and the motion in phase space is regular. For amplitudes exceeding a threshold value, the system become nonintegrable and the particle motion in phase space becomes stochastic. The stochasticity is caused by the overlapping of the adjacent resonances. The particle dynamics in various limits is discussed using a novel graphical technique for analyzing the particle motion. It is found that for ncosα > 1, the constant Hamiltonian surfaces are topologically closed and the maximum attainable particle energy is severely limited (n is the index of refraction and α is the wave propagation angle). For ncosα ≤ 1, however, the constant Hamiltonian surfaces are open due to relativistic correlations and the particles can gain large energies. A diffusion equation analogous to the Fokker-Planck equation is derived and used to examine the effect of the wave on an ensemble of particles. The model is applied to two different space applications. (i) It is shown that electrons can be accelerated by interacting with fundamental or second harmonic of an obliquely propagating cyclotron wave. This acceleration mechanism can explain the observed high energy electrons in solar type III bursts. (ii). The Kennel and Coroniti (1984) model of the Crab nebula is reexamined including the wave effects. A new model for the Crab nebula which accounts for the presence of radio electrons is proposed and its predictions compared to observations
High-energy tail distributions and resonant wave particle interaction
Leubner, M. P.
1983-01-01
High-energy tail distributions (k distributions) are used as an alternative to a bi-Lorentzian distribution to study the influence of energetic protons on the right- and left-hand cyclotron modes in a hot two-temperature plasma. Although the parameters are chosen to be in a range appropriate to solar wind or magnetospheric configurations, the results apply not only to specific space plasmas. The presence of energetic particles significantly alters the behavior of the electromagnetic ion cyclotron modes, leading to a wide range of unstable frequencies and increased growth rates. From the strongly enhanced growth rates it can be concluded that high-energy tail distributions should not show major temperature anisotropies, which is consistent with observations.
Wave particle interactions in the high-altitude polar cusp: a Cluster case study
Directory of Open Access Journals (Sweden)
B. Grison
2005-12-01
Full Text Available On 23 March 2002, the four Cluster spacecraft crossed in close configuration (~100 km separation the high-altitude (10 R_{E} cusp region. During a large part of the crossing, the STAFF and EFW instruments have detected strong electromagnetic wave activity at low frequencies, especially when intense field-aligned proton fluxes were detected by the CIS/HIA instrument. In all likelihood, such fluxes correspond to newly-reconnected field lines. A focus on one of these ion injection periods highlights the interaction between waves and protons. The wave activity has been investigated using the k-filtering technique. Experimental dispersion relations have been built in the plasma frame for the two most energetic wave modes. Results show that kinetic Alfvén waves dominate the electromagnetic wave spectrum up to 1 Hz (in the spacecraft frame. Above 0.8 Hz, intense Bernstein waves are also observed. The close simultaneity observed between the wave and particle events is discussed as an evidence for local wave generation. A mechanism based on current instabilities is consistent with the observations of the kinetic Alfvén waves. A weak ion heating along the recently-opened field lines is also suggested from the examination of the ion distribution functions. During an injection event, a large plasma convection motion, indicative of a reconnection site location, is shown to be consistent with the velocity perturbation induced by the large-scale Alfvén wave simultaneously detected.
Wave particle interactions in the high-altitude polar cusp: a Cluster case study
Directory of Open Access Journals (Sweden)
B. Grison
2005-12-01
Full Text Available On 23 March 2002, the four Cluster spacecraft crossed in close configuration (~100 km separation the high-altitude (10 RE cusp region. During a large part of the crossing, the STAFF and EFW instruments have detected strong electromagnetic wave activity at low frequencies, especially when intense field-aligned proton fluxes were detected by the CIS/HIA instrument. In all likelihood, such fluxes correspond to newly-reconnected field lines. A focus on one of these ion injection periods highlights the interaction between waves and protons. The wave activity has been investigated using the k-filtering technique. Experimental dispersion relations have been built in the plasma frame for the two most energetic wave modes. Results show that kinetic Alfvén waves dominate the electromagnetic wave spectrum up to 1 Hz (in the spacecraft frame. Above 0.8 Hz, intense Bernstein waves are also observed. The close simultaneity observed between the wave and particle events is discussed as an evidence for local wave generation. A mechanism based on current instabilities is consistent with the observations of the kinetic Alfvén waves. A weak ion heating along the recently-opened field lines is also suggested from the examination of the ion distribution functions. During an injection event, a large plasma convection motion, indicative of a reconnection site location, is shown to be consistent with the velocity perturbation induced by the large-scale Alfvén wave simultaneously detected.
Li, W.
2017-12-01
In the collisionless heliospheric plasmas, wave-particle interaction is a fundamental physical process in transferring energy and momentum between particles with different species and energies. This presentation focuses on one of the important wave-particle interaction processes: interaction between whistler-mode waves and electrons. Whistler-mode waves have frequencies between proton and electron cyclotron frequency and are ubiquitously present in the heliospheric plasmas including solar wind and planetary magnetospheres. I use Earth's Van Allen radiation belt as "local space laboratory" to discuss the role of whistler-mode waves in energetic electron dynamics using multi-satellite observations, theory and modeling. I further discuss solar wind drivers leading to energetic electron dynamics in the Earth's radiation belts, which is critical in predicting space weather that has broad impacts on our technological systems and society. At last, I discuss the unprecedented future opportunities of exploring space science using multi-satellite observations and state-of-the-art theory and modeling.
Direct observation of a 'devil's staircase' in wave-particle interaction
International Nuclear Information System (INIS)
Doveil, Fabrice; Macor, Alessandro; Elskens, Yves
2006-01-01
We report the experimental observation of a 'devil's staircase' in a time-dependent system considered as a paradigm for the transition to large-scale chaos in the universality class of Hamiltonian systems. A test electron beam is used to observe its non-self-consistent interaction with externally excited wave(s) in a traveling wave tube (TWT). A trochoidal energy analyzer records the beam energy distribution at the output of the interaction line. An arbitrary waveform generator is used to launch a prescribed spectrum of waves along the slow wave structure (a 4 m long helix) of the TWT. The resonant velocity domain associated to a single wave is observed, as well as the transition to large-scale chaos when the resonant domains of two waves and their secondary resonances overlap. This transition exhibits a 'devil's staircase' behavior for increasing excitation amplitude, due to the nonlinear forcing by the second wave on the pendulum-like motion of a charged particle in one electrostatic wave
Hsieh, Yi-Kai; Omura, Yoshiharu
2017-10-01
We investigate the properties of whistler mode wave-particle interactions at oblique wave normal angles to the background magnetic field. We find that electromagnetic energy of waves at frequencies below half the electron cyclotron frequency can flow nearly parallel to the ambient magnetic field. We thereby confirm that the gyroaveraging method, which averages the cyclotron motion to the gyrocenter and reduces the simulation from two-dimensional to one-dimensional, is valid for oblique wave-particle interaction. Multiple resonances appear for oblique propagation but not for parallel propagation. We calculate the possible range of resonances with the first-order resonance condition as a function of electron kinetic energy and equatorial pitch angle. To reveal the physical process and the efficiency of electron acceleration by multiple resonances, we assume a simple uniform wave model with constant amplitude and frequency in space and time. We perform test particle simulations with electrons starting at specific equatorial pitch angles and kinetic energies. The simulation results show that multiple resonances contribute to acceleration and pitch angle scattering of energetic electrons. Especially, we find that electrons with energies of a few hundred keV can be accelerated efficiently to a few MeV through the n = 0 Landau resonance.
Romanelli, N.; Mazelle, C.; Meziane, K.
2018-02-01
Seen from the solar wind (SW) reference frame, the presence of newborn planetary protons upstream from the Martian and Venusian bow shocks and SW protons reflected from each of them constitutes two sources of nonthermal proton populations. In both cases, the resulting proton velocity distribution function is highly unstable and capable of giving rise to ultralow frequency quasi-monochromatic electromagnetic plasma waves. When these instabilities take place, the resulting nonlinear waves are convected by the SW and interact with nonthermal protons located downstream from the wave generation region (upstream from the bow shock), playing a predominant role in their dynamics. To improve our understanding of these phenomena, we study the interaction between a charged particle and a large-amplitude monochromatic circularly polarized electromagnetic wave propagating parallel to a background magnetic field, from first principles. We determine the number of fix points in velocity space, their stability, and their dependence on different wave-particle parameters. Particularly, we determine the temporal evolution of a charged particle in the pitch angle-gyrophase velocity plane under nominal conditions expected for backstreaming protons in planetary foreshocks and for newborn planetary protons in the upstream regions of Venus and Mars. In addition, the inclusion of wave ellipticity effects provides an explanation for pitch angle distributions of suprathermal protons observed at the Earth's foreshock, reported in previous studies. These analyses constitute a mean to evaluate if nonthermal proton velocity distribution functions observed at these plasma environments present signatures that can be understood in terms of nonlinear wave-particle processes.
Kulp-McDowall, Taylor; Ochs, Ian; Fisch, Nathaniel
2016-10-01
A particle pusher was constructed in MATLAB using a fourth order Runge-Kutta algorithm to investigate the wave-particle interactions within theoretical models of the MCMF. The model simplified to a radial electric field and a magnetic field focused in the z direction. Studies on an average velocity calculation were conducted in order to test the program's behavior in the large radius limit. The results verified that the particle pusher was behaving correctly. Waves were then simulated on the rotating particles with a periodic divergenceless perturbation in the Bz component of the magnetic field. Preliminary runs indicate an agreement of the particle's motion with analytical predictions-ie. cyclic contractions of the doubly rotating particle's gyroradius.The next stage of the project involves the implementation of particle collisions and turbulence within the particle pusher in order to increase its accuracy and applicability. This will allow for a further investigation of the alpha channeling electrode replacement thesis first proposed by Abraham Fetterman in 2011. Made possible by Grants from the Princeton Environmental Institute (PEI) and the Program for Plasma Science and Technology (PPST).
Kletzing, C.
2017-12-01
The physics of the creation, loss, and transport of radiation belt particles is intimately connected to the electric and magnetic fields which mediate these processes. A large range of field and particle interactions are involved in this physics from large-scale ring current ion and magnetic field dynamics to microscopic kinetic interactions of whistler-mode chorus waves with energetic electrons. To measure these kinds of radiation belt interactions, NASA implemented the two-satellite Van Allen Probes mission. As part of the mission, the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) investigation is an integrated set of instruments consisting of a triaxial fluxgate magnetometer (MAG) and a Waves instrument which includes a triaxial search coil magnetometer (MSC). We show a variety of waves thought to be important for wave particle interactionsin the radiation belts: low frequency ULF pulsations, EMIC waves, and whistler mode waves including upper and lower band chorus. Outside ofthe radiation belts, Alfven waves play a key role in both solar wind turbulenceand auroral particle acceleration. Several of these wave modes could benefit (or have benefitted) from laboratory studies to further refineour understanding of the detailed physics of the wave-particle interactionswhich lead to energization, pitch angle scattering, and cross-field transportWe illustrate some of the processes and compare the wave data with particle measurements to show relationships between wave activity and particle processobserved in the inner magnetosphere and heliosphere.
Nonlinear interaction of fast particles with Alfven waves in toroidal plasmas
International Nuclear Information System (INIS)
Candy, J.; Borba, D.; Huysmans, G.T.A.; Kerner, W.; Berk, H.L.
1996-01-01
A numerical algorithm to study the nonlinear, resonant interaction of fast particles with Alfven waves in tokamak geometry has been developed. The scope of the formalism is wide enough to describe the nonlinear evolution of fishbone modes, toroidicity-induced Alfven eigenmodes and ellipticity-induced Alfven eigenmodes, driven by both passing and trapped fast ions. When the instability is sufficiently weak, it is known that the wave-particle trapping nonlinearity will lead to mode saturation before wave-wave nonlinearities are appreciable. The spectrum of linear modes can thus be calculated using a magnetohydrodynamic normal-mode code, then nonlinearly evolved in time in an efficient way according to a two-time-scale Lagrangian dynamical wave model. The fast particle kinetic equation, including the effect of orbit nonlinearity arising from the mode perturbation, is simultaneously solved of the deviation, δf = f - f 0 , from an initial analytic distribution f 0 . High statistical resolution allows linear growth rates, frequency shifts, resonance broadening effects, and nonlinear saturation to be calculated quickly and precisely. The results have been applied to an ITER instability scenario. Results show that weakly-damped core-localized modes alone cause negligible alpha transport in ITER-like plasmas--even with growth rates one order of magnitude higher than expected values. However, the possibility of significant transport in reactor-type plasmas due to weakly unstable global modes remains an open question
International Nuclear Information System (INIS)
Bourdier, A.
1999-01-01
This work concerns mainly the dynamics of a charged particle in an electromagnetic wave. It is a first step in elaborating a more general model permitting to predict the wave-particle interaction. We show how deriving a first integral gives an idea on how to create an electron current in a cold electron plasma. We present results which can be used to test the 2D and 3D Vlasov-Maxwell codes being built up in CEA-DAM. These codes will allow the calcination of the magnetic field created by an electromagnetic wave like the one due to the inverse Faraday effect when a circularly polarized wave drives the electrons of a plasma into circular orbits. (author)
Nonlinear theory of surface-wave--particle interactions in a cylindrical plasma
International Nuclear Information System (INIS)
Dengra, A.; Palop, J.I.F.
1994-01-01
This work is an application of the specular reflection hypothesis to the study of the nonlinear surface-wave--particle interactions in a cylindrical plasma. The model is based on nonlinear resolution of the Vlasov equation by the method of characteristics. The expression obtained for the rate of increase of kinetic energy per electron has permitted us to investigate the temporal behavior of nonlinear collisionless damping for different situations as a function of the critical parameters
Echterling, N.; Schriver, D.; Roeder, J. L.; Fennell, J. F.
2017-12-01
During the recovery phase of substorm plasma injections, the Van Allen Probes commonly observe events of quasi-periodic energetic electron bursts correlating with simultaneously detected upper-band, whistler-mode chorus emissions. These electron bursts exhibit narrow ranges of pitch angles (75-80° and 100-105°) and energies (20-40 keV). Electron cyclotron harmonic (ECH) emissions are also commonly detected, but typically do not display correlation with the electron bursts. To examine sources of free energy and the generation of these wave emissions, an observed electron velocity distribution on January 13, 2013 is used as the starting condition for a particle in cell (PIC) simulation. Effects of temperature anisotropy (perpendicular temperature greater than parallel temperature), the presence of a loss cone and a cold electron population on the generation of whistler and ECH waves are examined to understand wave generation and nonlinear interactions with the particle population. These nonlinear interactions produce energy diffusion along with strong pitch angle scattering into the loss cone on the order of milliseconds, which is faster than a typical bounce period of seconds. To examine the quasi-periodic nature of the electron bursts, a loss-cone recycling technique is implemented to model the effects of the periodic emptying of the loss cone and electron injection on the growth of whistler and ECH waves. The results of the simulations are compared to the Van Allen Probe observations to determine electron acceleration, heating and transport in Earth's radiation belts due to wave-particle interactions.
Method for constructing bound state wave functions of two interacting particles on nullplanes
International Nuclear Information System (INIS)
Leidigh, T.J.
1980-01-01
Nullplane position and momentum coordinates are defined in terms of the generators of the Poincare group. A transformation to center-of-mass and relative coordinates for a two-particle system is made. Then, another transformation from the original relative coordinates to a new set is made. In terms of the new relative coordinates the formal analogy with nonrelativistic quantum mechanics, already familiar in the nullplane formalism, is greatly enhanced. These coordinates do not appear to have been used previously. The most general form for a two-particle interaction is then partially determined and two methods for solving the remaining constraints are shown to be equivalent. The similarity to nonrelativistic quantum mechanics is used to solve a bound state problem with an interaction resembling a harmonic oscillator. The wave function is then used to model an unstable particle, which has zero spin in the limit in which the particle becomes stable. In the presence of the decay-producing interaction it is shown that the spin spectrum of the parent particle does not remain sharply zero. This is the first relativistic model to unequivocally display this result. The result is interpreted as indicating that real, relativistic, unstable particles may not possess a sharp spin spectrum
Euler-Lagrange Simulations of Shock Wave-Particle Cloud Interaction
Koneru, Rahul; Rollin, Bertrand; Ouellet, Frederick; Park, Chanyoung; Balachandar, S.
2017-11-01
Numerical experiments of shock interacting with an evolving and fixed cloud of particles are performed. In these simulations we use Eulerian-Lagrangian approach along with state-of-the-art point-particle force and heat transfer models. As validation, we use Sandia Multiphase Shock Tube experiments and particle-resolved simulations. The particle curtain upon interaction with the shock wave is expected to experience Kelvin-Helmholtz (KH) and Richtmyer-Meshkov (RM) instabilities. In the simulations evolving the particle cloud, the initial volume fraction profile matches with that of Sandia Multiphase Shock Tube experiments, and the shock Mach number is limited to M =1.66. Measurements of particle dispersion are made at different initial volume fractions. A detailed analysis of the influence of initial conditions on the evolution of the particle cloudis presented. The early time behavior of the models is studied in the fixed bed simulations at varying volume fractions and shock Mach numbers.The mean gas quantities are measured in the context of 1-way and 2-way coupled simulations. This work was supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, Contract No. DE-NA0002378.
International Nuclear Information System (INIS)
Kukhtin, V.V.; Kuzmenko, M.V.
2000-01-01
Complete text of publication follows. Recent studies (1) have shown that the Schroedinger nonrelativistic wave equation for a system of interacting particles is not a rigorously nonrelativistic one since it is based on the implicit assumption that the interaction propagation velocity is a finite value, which implies commutativity of the operators of coordinates and momenta of different particles. The refusal from this assumption implies their noncommutativity, which allows one to construct a truly nonrelativistic nonlinear self-consistent wave equation for a system of interacting particles. In the frame of the advanced wave equation, we investigate the spectrum of bound states for the two-body problem with the Yukawa potential V(r) = -V 0 a exp(-r/a)/r as a function of parameters of the potential. A peculiar feature of the spectrum is the presence of a critical value of V 0 (with the fixed parameter a), above which the given bound state cannot exist. In the ground state with l = 0 at a critical value of V 0 , the mean distance between particles takes the least value equal to the Compton wavelength of the particle with reduced mass. We estimate the parameter of noncommutativity ε for the operators of the coordinate of one particle and of the momentum of other one ([χ 1 , p 2x ] = i(h/2π)m 2 /M x ε) for the bound state of a deuteron, for which we consider the lowest state with l = 0 as its ground state. The parameter a of the Yukawa potential is taken to be equal to the Compton wavelength of a pion, 1.41 fm. In order to obtain the binding energy of a deuteron E = -2.22452 MeV, the parameter V 0 has to equal 51.23 MeV. In this case, the parameter of noncommutativity ε for the operators of the coordinate of one particle and of the momentum of other one ε = 0.0011, i.e., the commutator is nonzero even for such a weakly bound system as a deuteron where particles are located outside the region of action of nuclear forces for a significant fraction of time. Moreover
Auroral kilometric radiation - An example of relativistic wave-particle interaction in geoplasma
International Nuclear Information System (INIS)
Pritchett, P.L.
1990-01-01
The earth's auroral kilometric radiation (AKR) is believed to be produced by the electron-cyclotron maser instability. This instability is the result of a wave-particle interaction in which relativistic effects are crucial. An explanation is given as to how these relativistic effects alter the shape of the resonance curve in velocity space and modify the R - X mode wave dispersion near the electron cyclotron frequency compared to the results obtained in the nonrelativistic limit and from cold-plasma theory. The properties of the cyclotron maser instability in a driven system are illustrated using two-dimensional electromagnetic particle simulations which incorporate a continual flow of primary energetic electrons along the magnetic field. 31 refs
Wave, particle-family duality and the conservation of discrete symmetries in strong interaction
International Nuclear Information System (INIS)
van der Spuy, E.
1984-01-01
This paper starts from a nonlinear fermion field equation of motion with a strongly coupled self-interaction. Nonperturbative quark solutions of the equation of motion are constructed in terms of a Reggeized infinite component free spinor field. Such a field carries a family of strongly interacting unstable compounds lying on a Regge locus in the analytically continued quark spin. Such a quark field is naturally confined and also possesses the property of asymptotic freedom. Furthermore, the particular field self-regularizes the interactions and naturally breaks the chiral invariance of the equation of motion. We show why and how the existence of such a strongly coupled solution and its particle-family, wave duality forces a change in the field equation of motion such that it conserves C,P,T, although its individual interaction terms are of V-A and thus C,P nonconserving type
Nonlinear wave-particle interaction upstream from the Earth's bow shock
Directory of Open Access Journals (Sweden)
C. Mazelle
2000-01-01
Full Text Available Well-defined ring-like backstreaming ion distributions have been recently reported from observations made by the 3DP/PESA-High analyzer onboard the WIND spacecraft in the Earth's foreshock at large distances from the bow shock, which suggests a local production mechanism. The maximum phase space density for these distributions remains localized at a nearly constant pitch-angle value for a large number of gyroperiods while the shape of the distribution remains very steady. These distributions are also observed in association with quasi-monochromatic low frequency (~ 50 mHz waves with substantial amplitude (δB/B>0.2. The analysis of the magnetic field data has shown that the waves are propagating parallel to the background field in the right-hand mode. Parallel ion beams are also often observed in the same region before the observation of both the ring-like distributions and the waves. The waves appear in cyclotron resonance with the ion parallel beams. We investigate first the possibility that the ion beams could provide the free energy source for driving an ion/ion instability responsible for the ULF wave occurrence. For that, we solve the wave dispersion relation with the observed parameters. Second, we show that the ring-like distributions could then be produced by a coherent nonlinear wave-particle interaction. It tends to trap the ions into narrow cells in velocity space centered on a well-defined pitch-angle, directly related to the saturation wave amplitude in the analytical theory. The theoretical predictions are in good quantitative agreement with the observations
International Nuclear Information System (INIS)
Dengra, A.
1997-01-01
A new theoretical model for the study of the surface-wave endash particle interactions in a plasma column in the presence of a constant external magnetic field has been developed. The model is based on the linear resolution of the Vlasov equation by the method of characteristics, with the specular reflection hypothesis at the wall. The expression obtained for the rate of increase of kinetic energy per electron permits the analysis of the influence of the critical parameters in this transference process. copyright 1997 American Institute of Physics
Wave, particle-family duality and the conservation of discrete symmetries in strong interaction
International Nuclear Information System (INIS)
Van der Spuy, E.
1984-01-01
This paper starts from a nonlinear fermion field equation of motion with a strongly coupled selfinteraction. Nonperturbative quark solutions of the equation of motion are constructed in terms of a Reggeized infinite component free spinor field. Such a field carries a family of strongly interacting unstable compounds lying on a Regge locus in the analytically continued quark spin. Such a quark field is naturally confined and also possesses the property of asymptotic freedom. Furthermore the particular field selfregularizes the interactions and naturally breaks the chiral invariance of the equation of motion. We show why and how the existence of such a strongly coupled solution and its particle-family, wave duality forces a change in the field equation of motion such that it conserves C, P, T although its individual interaction terms are of V - A and thus C, P nonconserving type
Software-type Wave-Particle Interaction Analyzer on board the Arase satellite
Katoh, Yuto; Kojima, Hirotsugu; Hikishima, Mitsuru; Takashima, Takeshi; Asamura, Kazushi; Miyoshi, Yoshizumi; Kasahara, Yoshiya; Kasahara, Satoshi; Mitani, Takefumi; Higashio, Nana; Matsuoka, Ayako; Ozaki, Mitsunori; Yagitani, Satoshi; Yokota, Shoichiro; Matsuda, Shoya; Kitahara, Masahiro; Shinohara, Iku
2018-01-01
We describe the principles of the Wave-Particle Interaction Analyzer (WPIA) and the implementation of the Software-type WPIA (S-WPIA) on the Arase satellite. The WPIA is a new type of instrument for the direct and quantitative measurement of wave-particle interactions. The S-WPIA is installed on the Arase satellite as a software function running on the mission data processor. The S-WPIA on board the Arase satellite uses an electromagnetic field waveform that is measured by the waveform capture receiver of the plasma wave experiment (PWE), and the velocity vectors of electrons detected by the medium-energy particle experiment-electron analyzer (MEP-e), the high-energy electron experiment (HEP), and the extremely high-energy electron experiment (XEP). The prime objective of the S-WPIA is to measure the energy exchange between whistler-mode chorus emissions and energetic electrons in the inner magnetosphere. It is essential for the S-WPIA to synchronize instruments to a relative time accuracy better than the time period of the plasma wave oscillations. Since the typical frequency of chorus emissions in the inner magnetosphere is a few kHz, a relative time accuracy of better than 10 μs is required in order to measure the relative phase angle between the wave and velocity vectors. In the Arase satellite, a dedicated system has been developed to realize the time resolution required for inter-instrument communication. Here, both the time index distributed over all instruments through the satellite system and an S-WPIA clock signal are used, that are distributed from the PWE to the MEP-e, HEP, and XEP through a direct line, for the synchronization of instruments within a relative time accuracy of a few μs. We also estimate the number of particles required to obtain statistically significant results with the S-WPIA and the expected accumulation time by referring to the specifications of the MEP-e and assuming a count rate for each detector.
Electron Fluid Description of Wave-Particle Interactions in Strong Buneman Turbulence
Che, Haihong
2013-10-01
To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation associated with electron heating in Buneman instability. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions can be described by a set of electron fluid equations. These equations show that the energy dissipation and momentum transports in Buneman instability are locally quasi-static but globally non-static and irreversible. Turbulence drag dissipates both the bulk energy of electron streams and the associated magnetic energy. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons. The net loss of streaming energy is converted into electron heat and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation which relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drives local momentum transports, while phase mixing converts convective momentum into thermal momentum.These two local momentum transports sustain the Buneman waves and act as the micro-macro link in the anomalous heating process. This research is supported by the NASA Postdoctoral Program at NASA/GSFC administered by Oak Ridge Associated Universities through a contract with NASA.
The interaction of energetic alpha-particles with intense lower hybrid waves
International Nuclear Information System (INIS)
Fisch, N.J.; Rax, J.M.
1992-06-01
Lower hybrid waves are a demonstrated, continuous means of driving toroidal current in a tokamak. When these waves propagate in a tokamak fusion reactor, in which there are energetic α- particles, there are conditions under which the α-particles do not appreciably damp, and may even amplify, the wave, thereby enhancing the current-drive effect. Waves traveling in one poloidal direction, in addition to being directed in one toroidal direction, are shown to be the most efficient drivers of current in the presence of the energetic α-particles
Elkington, S. R.; Alam, S. S.; Chan, A. A.; Albert, J.; Jaynes, A. N.; Baker, D. N.; Wiltberger, M. J.
2017-12-01
Global simulations of radiation belt dynamics are often undertaken using either a transport formalism (e.g. Fokker-Plank), or via test particle simulations in model electric and magnetic fields. While transport formalisms offer computational efficiency and the ability to deal with a wide range of wave-particle interactions, they typically rely on simplified background fields, and often are limited to empirically-specified stochastic (diffusive) wave-particle interactions. On the other hand, test particle simulations may be carried out in global MHD simulations that include realistic physical effects such as magnetopause shadowing, convection, and substorm injections, but lack the ability to handle physics outside the MHD approximation in the realm of higher frequency (kHz) wave populations.In this work we introduce a comprehensive simulation framework combining global MHD/test particle techniques to provide realistic background fields and radial transport processes, with a Stochastic Differential Equation (SDE) method for addressing high frequency wave-particle interactions. We examine the March 17, 2013 storm-time acceleration period, an NSF-GEM focus challenge event, and use the framework to examine the relative importance of physical effects such as magnetopause shadowing, diffusive and advective transport processes, and wave-particle interactions through the various phases of the storm.
Microscopic dynamics of plasmas and chaos: the wave-particle interaction paradigm
International Nuclear Information System (INIS)
Escande, D F; Elskens, Y
2003-01-01
The wave-particle interaction is central to microscopic plasma dynamics. A paradigm of such an interaction is one occurring during the weak warm beam-plasma instability: a Langmuir turbulence sets in and saturates by the formation of a plateau in the particle distribution function. A new approach permits us to deal with the regular and chaotic aspects of this problem using the classical mechanics of the corresponding N-body problem only. The classical Landau-van Kampen theory is recovered by using mathematical tools not more intricate than a finite Fourier sum. A single calculation yields spontaneous emission and the particle dynamics as well; classical explicative models of Landau damping are found to be misleading. Recent tools of Hamiltonian chaos enable us to derive the quasilinear equations in the regime of saturation of the instability. The calculations are readable by graduate students and provide a simple solution to a 20 year old controversy in the Vlasovian frame. As a result, the macroscopic irreversible evolution of a plasma is described by fully accounting for its microscopic reversible mechanics; for the first time, an old dream of the 19th century comes true: the irreversible evolution of an N-body problem is described by taking into account the true character of its chaotic motion
On the stochastic interaction of monochromatic Alfven waves with toroidally trapped particles
International Nuclear Information System (INIS)
Krlin, L.; Pavlo, P.; Tluchor, Z.; Gasek, Z.
1987-07-01
Monochromatic Alfven wave interaction with toroidaly trapped particles in the intrinsic stochasticity regime is discussed. Both the diffusion in velocities and in the radial position of bananas is studied. Using a suitable Hamiltonian formalism, the effect of wave parallel components E-tilde paral and B-tilde paral is investigated. The stochasticity threshold is estimated for plasma electrons and for thermonuclear alpha-particles (neglecting the effect of B-tilde paral ) by means of direct numerical integration of the corresponding canonical equations. Stochasticity causes transfer between trapped and untrapped regimes and the induced radial diffusion of bananas. The latter effect can considerably exceed neoclassical diffusion. The effect of B-tilde paral was only estimated analytically. It consisted in frequency modulation of the banana periodic motion coupled with a possible Mathieu instability. Nevertheless, for B-tilde paral corresponding to E-tilde paral , the effect seems to be weaker than the effect of E-tilde paral when the thermonuclear regime is considered. (author). 14 figs., 36 refs
Alfven-wave particle interaction in finite-dimensional self-consistent field model
International Nuclear Information System (INIS)
Padhye, N.; Horton, W.
1998-01-01
A low-dimensional Hamiltonian model is derived for the acceleration of ions in finite amplitude Alfven waves in a finite pressure plasma sheet. The reduced low-dimensional wave-particle Hamiltonian is useful for describing the reaction of the accelerated ions on the wave amplitudes and phases through the self-consistent fields within the envelope approximation. As an example, the authors show for a single Alfven wave in the central plasma sheet of the Earth's geotail, modeled by the linear pinch geometry called the Harris sheet, the time variation of the wave amplitude during the acceleration of fast protons
Two-fluid description of wave-particle interactions in strong Buneman turbulence
Energy Technology Data Exchange (ETDEWEB)
Che, H. [NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States)
2014-06-15
To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation while a plasma is unstable to the Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. We show that both energy dissipation and momentum transport along electric current in the current layer are locally quasi-static, but globally dynamic and irreversible. Turbulent drag dissipates both the streaming energy of the current sheet and the associated magnetic energy. The net loss of streaming energy is converted into the electron component heat conduction parallel to the magnetic field and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation that relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drive local momentum transports, while phase mixing converts convective momentum into thermal momentum. The drag acts like a micro-macro link in the anomalous heating processes. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons, but most of the magnetic energy is dissipated and converted into the component heat of electrons perpendicular to the magnetic field. This heating process is decoupled from the heating of Buneman instability in the current sheets. Ion heating is weak but ions play an important role in assisting energy exchanges between waves and electrons. Cold ion fluid equations together with our electron fluid equations form a complete set of equations that describes the occurrence, growth, saturation and decay of the Buneman instability.
Two-fluid description of wave-particle interactions in strong Buneman turbulence
Che, H.
2014-06-01
To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation while a plasma is unstable to the Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. We show that both energy dissipation and momentum transport along electric current in the current layer are locally quasi-static, but globally dynamic and irreversible. Turbulent drag dissipates both the streaming energy of the current sheet and the associated magnetic energy. The net loss of streaming energy is converted into the electron component heat conduction parallel to the magnetic field and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation that relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drive local momentum transports, while phase mixing converts convective momentum into thermal momentum. The drag acts like a micro-macro link in the anomalous heating processes. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons, but most of the magnetic energy is dissipated and converted into the component heat of electrons perpendicular to the magnetic field. This heating process is decoupled from the heating of Buneman instability in the current sheets. Ion heating is weak but ions play an important role in assisting energy exchanges between waves and electrons. Cold ion fluid equations together with our electron fluid equations form a complete set of equations that describes the occurrence, growth, saturation and decay of the Buneman instability.
Two-fluid description of wave-particle interactions in strong Buneman turbulence
International Nuclear Information System (INIS)
Che, H.
2014-01-01
To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation while a plasma is unstable to the Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. We show that both energy dissipation and momentum transport along electric current in the current layer are locally quasi-static, but globally dynamic and irreversible. Turbulent drag dissipates both the streaming energy of the current sheet and the associated magnetic energy. The net loss of streaming energy is converted into the electron component heat conduction parallel to the magnetic field and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation that relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drive local momentum transports, while phase mixing converts convective momentum into thermal momentum. The drag acts like a micro-macro link in the anomalous heating processes. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons, but most of the magnetic energy is dissipated and converted into the component heat of electrons perpendicular to the magnetic field. This heating process is decoupled from the heating of Buneman instability in the current sheets. Ion heating is weak but ions play an important role in assisting energy exchanges between waves and electrons. Cold ion fluid equations together with our electron fluid equations form a complete set of equations that describes the occurrence, growth, saturation and decay of the Buneman instability
SCIDAC Center for simulation of wave particle interactions CompX participation
Energy Technology Data Exchange (ETDEWEB)
Harvey, R.W. [CompX, Del Mar, CA (United States)
2017-11-14
Harnessing the energy that is released in fusion reactions would provide a safe and abundant source of power to meet the growing energy needs of the world population. The next step toward the development of fusion as a practical energy source is the construction of ITER, a device capable of producing and controlling the high performance plasma required for self-sustaining fusion reactions, or “burning” plasma. The input power required to drive the ITER plasma into the burning regime will be supplied primarily with a combination of external power from radio frequency waves in the ion cyclotron range of frequencies and energetic ions from neutral beam injection sources, in addition to internally generated Ohmic heating from the induced plasma current that also serves to create the magnetic equilibrium for the discharge. The ITER project is a large multi-billion dollar international project in which the US participates. The success of the ITER project depends critically on the ability to create and maintain burning plasma conditions, it is absolutely necessary to have physics-based models that can accurately simulate the RF processes that affect the dynamical evolution of the ITER discharge. The Center for Simulation of WavePlasma Interactions (CSWPI), also known as RF-SciDAC, is a multi-institutional collaboration that has conducted ongoing research aimed at developing: (1) Coupled core-to-edge simulations that will lead to an increased understanding of parasitic losses of the applied RF power in the boundary plasma between the RF antenna and the core plasma; (2) Development of models for core interactions of RF waves with energetic electrons and ions (including fusion alpha particles and fast neutral beam ions) that include a more accurate representation of the particle dynamics in the combined equilibrium and wave fields; and (3) Development of improved algorithms that will take advantage of massively parallel computing platforms at the petascale level and
Electron and VLF travel time differences for wave-particle interactions at L=4: Pt. 2
International Nuclear Information System (INIS)
Rash, J.P.S.; Scourfield, M.W.J.; Dougherty, M.K.
1984-01-01
The cyclotron resonance or gyroresonance interaction has been widely invoked as a generation mechanism for discrete VLF emissions and plasmaspheric hiss. This interaction involves electrons and VLF waves travelling in opposite directions along a geomagnetic field line. We examine, for an interaction region in the equatorial plane at L=4, the energy of the resonant electrons as a function of VLF wave frequency and ambient equatorial electron density. Then for two different spatial configurations of the interaction and two standard plasma distribution models we examine the difference in travel times to a ground-based observer in the Southern hemisphere for the electrons and waves taking part in the interaction. This difference in travel times is shown as a function of VLF wave frequency and equatorial electron density. The results, and their significance for observations of auroral electrons and VLF at Sanae, Antarctica, are discussed and compared with similar results for the Cerenkov interaction discussed in an earlier paper
Directory of Open Access Journals (Sweden)
H. Tadokoro
2009-04-01
Full Text Available It has been believed that electrons in the inner belt do not show the dynamical variation during magnetic storms except for great magnetic storms. However, Tadokoro et al. (2007 recently disclosed that low-altitude electrons in the inner belt frequently show flux variations during storms (Storm Time inner belt Electron Enhancement at the Low altitude (STEEL. This paper investigates a possible mechanism explaining STEEL during small and moderate storms, and shows that it is caused not by radial transport processes but by pitch angle scattering through wave-particle interactions. The waves related to wave-particle interactions are attributed to be banded whistler mode waves around 30 kHz observed in the inner magnetosphere by the Akebono satellite. The estimated pitch angle distribution based on a numerical calculation is roughly consistent with the observed results.
Effect of nonlinear wave-particle interaction on electron-cyclotron absorption
Energy Technology Data Exchange (ETDEWEB)
Tsironis, C; Vlahos, L [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)
2006-09-15
We perform a self-consistent analysis of the nonlinear interaction of magnetized plasmas with electron-cyclotron (EC) waves. A closed set of equations is derived, which consists of the relativistic equations of motion under the wave field and the wave equation for the vector potential. The plasma is described in terms of ensembles of electrons which collectively determine the evolution of the wave amplitude and frequency through the current response. This description allows for effects of the electron motions on the efficiency of the wave absorption, for example, the asynchrony between the wave phase and the gyroperiod. As an application, we study the absorption of an EC wave beam in a simplified tokamak geometry, for plasma parameters relevant to current and future fusion experiments. We conclude that, within the limits of our model, there are cases where the linear theory for the absorption of EC waves, used widely in the current literature, may overestimate the energy deposition. In such cases, nonlinear effects are essential for the accurate estimation of the plasma-wave coupling and their inclusion should be considered, especially when the wave power is dramatically increased as in the case of ITER.
Effect of nonlinear wave-particle interaction on electron-cyclotron absorption
International Nuclear Information System (INIS)
Tsironis, C; Vlahos, L
2006-01-01
We perform a self-consistent analysis of the nonlinear interaction of magnetized plasmas with electron-cyclotron (EC) waves. A closed set of equations is derived, which consists of the relativistic equations of motion under the wave field and the wave equation for the vector potential. The plasma is described in terms of ensembles of electrons which collectively determine the evolution of the wave amplitude and frequency through the current response. This description allows for effects of the electron motions on the efficiency of the wave absorption, for example, the asynchrony between the wave phase and the gyroperiod. As an application, we study the absorption of an EC wave beam in a simplified tokamak geometry, for plasma parameters relevant to current and future fusion experiments. We conclude that, within the limits of our model, there are cases where the linear theory for the absorption of EC waves, used widely in the current literature, may overestimate the energy deposition. In such cases, nonlinear effects are essential for the accurate estimation of the plasma-wave coupling and their inclusion should be considered, especially when the wave power is dramatically increased as in the case of ITER
Magnetospheric conditions at the time of enhanced wave-particle interactions near the plasmapause
International Nuclear Information System (INIS)
Foster, J.C.; Rosenberg, T.J.; Lanzerotti, L.J.
1976-01-01
The morphology of geomagnetic and particle disturbances occurring in the American sector during the 0700--1000 UT time interval on January 2, 1971, is examined. This period includes the VLF/X ray burst correlation event that was detected near the plasmapause at Lapprox.4 in the vicinity of Siple Station, Antarctica (Rosenberg et al., 1971; Foster and Rosenberg, 1976a). It is found that a sequence of substorm intensifications occurred (0730, 0820, 0850, and 0925 UT), successive intensifications tending to occur more westwardly than the preceding ones. The last intensification in the sequence was confined principally to latitudes higher than the nominal auroral zone. Injections of energetic electrons into the night side magnetosphere were observed at Lapprox.6.6 during the intensifications at approx.0820 and approx.0850 UT. The onset and pronounced temporal and spectral features of the electron precipitation at Lapprox.4 near dawn can be related to these electron injections when cross-L inward convection and azimuthal drit are considered. It is suggested that injected electrons penetrated at least to the region just outside the plasmapause during the substorm and that simultaneous electron precipitation and VLF wave generation were associated with the onset of cyclotron resonance interactions following the arrival of the electrons on the field line over Siple Station
Effects on Ion Cyclotron Emission of the Orbit Topology Changes from the Wave-Particle Interactions
International Nuclear Information System (INIS)
Hellsten, T.; Holmstroem, K.; Johnson, T.; Bergkvist, T.; Laxaback, M.
2006-01-01
It is known that non-relaxed distribution functions can give rise to excitation of magnetosonic waves by ion cyclotron interactions when the distribution function increases with respect to the perpendicular velocity. We have found that in a toroidal plasma also collisional relaxed distribution functions of central peaked high-energy ions can destabilise magnetosonic eigenmodes by ion cyclotron interactions, due to the change in localisation of the orbits establishing inverted distribution functions with respect to energy along the characteristics describing the cyclotron interactions. This can take place by interactions with barely co-passing and marginally trapped high-energy ions at the plasma boundary. The interactions are enhanced by tangential interactions, which can also prevent the interactions to reach the stable part of the characteristics where they interact with more deeply trapped orbits. (author)
International Nuclear Information System (INIS)
Klimushkin, D.Yu.
1998-01-01
The effect of bounce-drift instability on the structure of small-scale azimuthal Alfven waves in the magnetosphere is studied with allowance for the curvature of the geomagnetic field lines. The pressure of the background plasma is assumed to be zero. As early as 1993, Leonovich and Mazur showed that Alfven waves with m>>1, being standing waves along magnetic field lines, propagate, at the same time, across the magnetic surfaces. As these waves propagate through the magnetosphere, they interact with a group of high-energy particles and, thereby, are amplified with a growth rate dependent on the radial coordinate, i.e., a coordinate perpendicular to the magnetic sheaths. Near the Alfven resonance surface, the growth rate approaches zero, and the waves are damped completely due to the energy dissipation in the ionosphere. As the growth rate increases, the maximum of the wave amplitude is displaced to the Alfven resonance region and the most amplified waves are those whose magnetic field vectors oscillate in the azimuthal direction. Among the waves excited in a plasma resonator that is formed near the plasmapause, the most amplified are those with radial polarization
Tripathi, A. K.; Singhal, R. P.; Khazanov, G. V.; Avanov, L. A.
2016-01-01
Electron pitch angle (D (alpha)) and momentum (D(pp)) diffusion coefficients have been calculated due to resonant interactions with electrostatic electron cyclotron harmonic (ECH) and whistler mode chorus waves. Calculations have been performed at two spatial locations L = 4.6 and 6.8 for electron energies 10 keV. Landau (n = 0) resonance and cyclotron harmonic resonances n = +/-1, +/-2,...+/-5 have been included in the calculations. It is found that diffusion coefficient versus pitch angle (alpha) profiles show large dips and oscillations or banded structures. The structures are more pronounced for ECH and lower band chorus (LBC) and particularly at location 4.6. Calculations of diffusion coefficients have also been performed for individual resonances. It is noticed that the main contribution of ECH waves in pitch angle diffusion coefficient is due to resonances n = +1 and n = +2. A major contribution to momentum diffusion coefficients appears from n = +2. However, the banded structures in D alpha and Dpp coefficients appear only in the profile of diffusion coefficients for n = +2. The contribution of other resonances to diffusion coefficients is found to be, in general, quite small or even negligible. For LBC and upper band chorus waves, the banded structures appear only in Landau resonance. The Dpp diffusion coefficient for ECH waves is one to two orders smaller than D alpha coefficients. For chorus waves, Dpp coefficients are about an order of magnitude smaller than D alpha coefficients for the case n does not = 0. In case of Landau resonance, the values of Dpp coefficient are generally larger than the values of D alpha coefficients particularly at lower energies. As an aid to the interpretation of results, we have also determined the resonant frequencies. For ECH waves, resonant frequencies have been estimated for wave normal angle 89 deg and harmonic resonances n = +1, +2, and +3, whereas for whistler mode waves, the frequencies have been calculated for angle
Tripathi, A. K.; Singhal, R. P.; Khazanov, G. V.; Avanov, L. A.
2016-01-01
Electron pitch angle (D(sub (alpha alpha))) and momentum (D(sub pp)) diffusion coefficients have been calculated due to resonant interactions with electrostatic electron cyclotron harmonic (ECH) and whistler mode chorus waves. Calculations have been performed at two spatial locations L=4.6 and 6.8 for electron energies less than or equal to 10 keV. Landau (n=0) resonance and cyclotron harmonic resonances n= +/- 1, +/-2, ... +/-5 have been included in the calculations. It is found that diffusion coefficient versus pitch angle (alpha) profiles show large dips and oscillations or banded structures. The structures are more pronounced for ECH and lower band chorus (LBC) and particularly at location 4.6. Calculations of diffusion coefficients have also been performed for individual resonances. It is noticed that the main contribution of ECH waves in pitch angle diffusion coefficient is due to resonances n=+1 and n=+2. A major contribution to momentum diffusion coefficients appears from n=+2. However, the banded structures in D(sub alpha alpha) and D(sub pp) coefficients appear only in the profile of diffusion coefficients for n=+2. The contribution of other resonances to diffusion coefficients is found to be, in general, quite small or even negligible. For LBC and upper band chorus waves, the banded structures appear only in Landau resonance. The D(sub pp) diffusion coefficient for ECH waves is one to two orders smaller than D(sub alpha alpha) coefficients. For chorus waves, D(sub pp) coefficients are about an order of magnitude smaller than D(sub alpha alpha) coefficients for the case n does not equal 0. In case of Landau resonance, the values of D(sub pp) coefficient are generally larger than the values of D(sub alpha alpha) coefficients particularly at lower energies. As an aid to the interpretation of results, we have also determined the resonant frequencies. For ECH waves, resonant frequencies have been estimated for wave normal angle 89 deg and harmonic resonances
International Nuclear Information System (INIS)
Escande, D F; Elskens, Yves; Doveil, F
2015-01-01
The derivation of Debye shielding and Landau damping from the N-body description of plasmas is performed directly by using Newton’s second law for the N-body system. This is done in a few steps with elementary calculations using standard tools of calculus and no probabilistic setting. Unexpectedly, Debye shielding is encountered together with Landau damping. This approach is shown to be justified in the one-dimensional case when the number of particles in a Debye sphere becomes large. The theory is extended to accommodate a correct description of trapping and chaos due to Langmuir waves. On top of their well-known production of collisional transport, the repulsive deflections of electrons are shown to produce shielding, in such a way that each particle is shielded by all other ones, while keeping in uninterrupted motion. (paper)
Barbosa, D. D.
1986-01-01
A theory of medium-energy (about keV) electrons and heavy ions in Jupiter's magnetosphere is presented. Lower hybrid waves are generated by the combined effects of a ring instability of neutral wind pickup ions and the modified two-stream instability associated with transport of cool Iogenic plasma. The quasi-linear energy diffusion coefficient for lower hybrid wave-particle interactions is evaluated, and several solutions to the diffusion equation are given. Calculations based on measured wave properties show that the noise substantially modifies the particle distribution functions. The effects are to accelerate superthermal ions and electrons to keV energies and to thermalize the pickup ions on time scales comparable to the particle residence time. The S(2+)/S(+) ratio at medium energies is a measure of the relative contribution from Iogenic thermal plasma and neutral wind ions, and this important quantity should be determined from future measurements. The theory also predicts a preferential acceleration of heavy ions with an accleration time that scales inversely with the root of the ion mass. Electrons accelerated by the process contribute to further reionization of the neutral wind by electron impact, thus providing a possible confirmation of Alfven's critical velocity effect in the Jovian magnetosphere.
Huang, S.; Sahraoui, F.; Yuan, Z.; He, J.; Zhao, J.; Du, J.; Le Contel, O.; Wang, X.; Deng, X.; Fu, H.; Zhou, M.; Shi, Q.; Breuillard, H.; Pang, Y.; Yu, X.; Wang, D.
2017-12-01
Magnetic hole is characterized by a magnetic depression, a density peak, a total electron temperature increase (with a parallel temperature decrease but a perpendicular temperature increase), and strong currents carried by the electrons. The current has a dip in the core region of the magnetic hole and a peak in the outer region of the magnetic hole. There is an enhancement in the perpendicular electron fluxes at 90° pitch angles inside the magnetic hole, implying that the electrons are trapped within it. The variations of the electron velocity components Vem and Ven suggest that an electron vortex is formed by trapping electrons inside the magnetic hole in the circular cross-section. These observations demonstrate the existence of a new type of coherent structures behaving as an electron vortex magnetic hole in turbulent space plasmas as predicted by recent kinetic simulations. We perform a statistically study using high time solution data from the MMS mission. The magnetic holes with short duration (i.e., < 0.5 s) have their cross section smaller than the ion gyro-radius. Superposed epoch analysis of all events reveals that an increase in the electron density and total temperature, significantly increase (resp. decrease) the electron perpendicular (resp. parallel) temperature, and an electron vortex inside the holes. Electron fluxes at 90° pitch angles with selective energies increase in the KSMHs, are trapped inside KSMHs and form the electron vortex due to their collective motion. All these features are consistent with the electron vortex magnetic holes obtained in 2D and 3D particle-in-cell simulations, indicating that the observed the magnetic holes seem to be best explained as electron vortex magnetic holes. It is furthermore shown that the magnetic holes are likely to heat and accelerate the electrons. We also investigate the coupling between whistler waves and electron vortex magnetic holes. These whistler waves can be locally generated inside electron
Study of wave-particle interaction from the linear regime to dynamical chaos in a magnetized plasma
International Nuclear Information System (INIS)
Fasoli, A.
1993-10-01
Deterministic chaos generated by the interaction between charged particles and electrostatic plasma waves has been observed in a linear magnetized plasma. The target plasma is created by a barium Q-source, guaranteeing low fluctuation levels and a high degree of uniformity over an extended plasma volume. Characteristics of the background plasma are investigated by a variety of diagnostic techniques, including laser induced fluorescence (LIF) and optical tagging (OT). Particular tagging schemes and specific theoretical approaches to data interpretation (both for LIF and OT) have been developed during this work. As part of these background plasma studies, special attention has been devoted to an investigation of test-ion cross-field transport under different conditions. Test-ions are created and followed in their motion across the magnetic field lines via spin state tagging. In the unperturbed plasma this motion is found to be a diffusive process, supported by classical mechanisms, even in the presence of relatively high pressures of non-reactive neutral gases injected into the plasma volume. Electrostatic waves are excited using a ring antenna structure encircling the plasma column and electrically isolated from it. This system has been chosen on the basis of a comparative analysis of different ion wave launching methods, including the use of grids, inductive coils coupled electromagnetically to the plasma and modulated high frequency electron waves. Two modes propagating parallel to the magnetic field, one of which has two perpendicular components (ion Bernstein and ion acoustic-like waves), characterize the spectrum excited by the electrostatic ring antenna for a single frequency, f, chosen in the range f ci ci . (author) figs., tabs., 134 refs
Particle-in-cell analysis of beam-wave interaction in gyrotron cavity with tapered magnetic field
Energy Technology Data Exchange (ETDEWEB)
Kumar, A., E-mail: anil.gyrotron@gmail.com [Gyrotron Lab., Microwave Tube Area, Central Electronics Engineering Research Inst. (CEERI, CSIR), Pilani, Rajasthan (India); Banasthali Univ., Dept. of Physics, Banasthali, Rajasthan (India); Khatun, H.; Kumar, N.; Singh, U.; Sinha, A.K. [Gyrotron Lab., Microwave Tube Area, Central Electronics Engineering Research Inst. (CEERI, CSIR), Pilani, Rajasthan (India); Vyas, V. [Banasthali Univ., Dept. of Physics, Banasthali, Rajasthan (India)
2010-11-15
A commercially available electromagnetic simulator -- MAGIC, a particle-in-cell (PIC) code -- has been used to carry out a comparative study of the beam-wave interaction under uniform and tapered magnetic field profiles of a 42 GHz, 200kW gyrotron. The magnetic field profile across the resonant cavity varies by ±6.5% with a peak value of 1.615 T. The MAGIC simulation shows the desire performance of the gyrotron under both magnetic field conditions with an operating mode TE{sub 03} and a pitch factor of 1.26. The analysis of the simulated results show that stability in the power growth was reached more quickly and achieved higher output power in the case of a tapered magnetic field. (author)
Elementary particles and particle interactions
International Nuclear Information System (INIS)
Bethge, K.; Schroeder, U.E.
1986-01-01
This book is a textbook for an introductory course of elementary particle physics. After a general introduction the symmetry principles governing the interactions of elementary particles are discussed. Then the phenomenology of the electroweak and strong interactions are described together with a short introduction to the Weinberg-Salam theory respectively to quantum chromodynamics. Finally a short outlook is given to grand unification with special regards to SU(5) and cosmology in the framework of the current understanding of the fundamental principles of nature. In the appendix is a table of particle properties and physical constants. (HSI) [de
Quasi-coherent chorus properties: 1. Implications for wave-particle interactions
Czech Academy of Sciences Publication Activity Database
Tsurutani, B. T.; Falkowski, B. J.; Verkhoglyadova, O. P.; Pickett, J. S.; Santolík, Ondřej; Lakhina, D. G.
2011-01-01
Roč. 116, - (2011), A09210/1-A09210/18 ISSN 0148-0227 R&D Projects: GA ČR GAP205/10/2279; GA MŠk(CZ) ME10001 Institutional research plan: CEZ:AV0Z30420517 Keywords : WHISTLER-MODE CHORUS * RELATIVISTIC ELECTRON MICROBURSTS * PITCH ANGLE SCATTERING * RADIATION BELT * AURORAL-ZONE * RESONANT DIFFUSION * MAGNETIC STORMS * GENDRIN MODE * VLF WAVES * MAGNETOSPHERE Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.021, year: 2011 http://www.agu.org/pubs/crossref/2011/2010JA016237.shtml
Convery, P. D.; Schriver, D.; Ashour-Abdalla, M.; Richard, R. L.
2002-01-01
Nongyrotropic plasma distribution functions can be formed in regions of space where guiding center motion breaks down as a result of strongly curved and weak ambient magnetic fields. Such are the conditions near the current sheet in the Earth's middle and distant magnetotail, where observations of nongyrotropic ion distributions have been made. Here a systematic parameter study of nongyrotropic proton distributions using electromagnetic hybrid simulations is made. We model the observed nongyrotropic distributions by removing a number of arc length segments from a cold ring distribution and find significant differences with the results of simulations that initially have a gyrotropic ring distribution. Model nongyrotropic distributions with initially small perpendicular thermalization produce growing fluctuations that diffuse the ions into a stable Maxwellian-like distribution within a few proton gyro periods. The growing waves produced by nongyrotropic distributions are similar to the electromagnetic proton cyclotron waves produced by a gyrotropic proton ring distribution in that they propagate parallel to the background magnetic field and occur at frequencies on the order of the proton gyrofrequency, The maximum energy of the fluctuating magnetic field increases as the initial proton distribution is made more nongyrotropic, that is, more highly bunched in perpendicular velocity space. This increase can be as much as twice the energy produced in the gyrotropic case.
International Nuclear Information System (INIS)
Bourdier, A.; Patin, D.
2005-01-01
The basic physical processes in laser-matter interaction, up to 10 17 W/cm 2 (for a neodymium laser) are now well understood, on the other hand, new phenomena evidenced in particle-in-cell code simulations have to be investigated above 10 18 W/cm 2 . Thus, the relativistic motion of a charged particle in a linearly polarized homogeneous electromagnetic wave is studied, here, using the Hamiltonian formalism. First, the motion of a single particle in a linearly polarized traveling wave propagating in a non-magnetized space is explored. The problem is shown to be integrable. The results obtained are compared to those derived considering a cold electron plasma model. When the phase velocity is close to c, it is shown that the two approaches are in good agreement during a finite time. After this short time, when the plasma response is taken into account no chaos take place at least when considering low densities and/or high wave intensities. The case of a charged particle in a traveling wave propagating along a constant homogeneous magnetic field is then considered. The problem is shown to be integrable when the wave propagates in vacuum. The existence of a synchronous solution is shown very simply. In the case when the wave propagates in a low density plasma, using a simplifying Lorentz transformation, it is shown that the system can be reduced to a time-dependent system with two degrees of freedom. The system is shown to be non-integrable, chaos appears when a secondary resonance and a primary resonance overlap. Finally, stochastic instabilities are studied by considering the motion of one particle in a very high intensity wave perturbed by one or two low intensity traveling waves. Resonances are identified and conditions for resonance overlap are studied. (authors)
International Nuclear Information System (INIS)
Dulk, G.A.; Goldman, M.V.; Toomre, J.
1985-01-01
Activities in the following study areas are reported: (1) particle and wave processes in solar flares; (2) solar convection zone turbulence; and (3) solar radiation emission. To investigate the amplification of cyclotron maser radiation in solar flares, a radio frequency. (RF) heating model was developed for the corona surrounding the energy release site. Then nonlinear simulations of compressible convection display prominent penetration by plumes into regions of stable stratification at the base of the solar convection zone, leading to the excitation of internal gravity waves there. Lastly, linear saturation of electron-beam-driven Langmuir waves by ambient density fluctuations, nonlinear saturation by strong turbulence processes, and radiation emission mechanisms are examined. An additional section discusses solar magnetic fields and hydromagnetic waves in inhomogeneous media, and the effect of magnetic fields on stellar oscillation
Elementary particle interactions
International Nuclear Information System (INIS)
Bugg, W.M.; Condo, G.T.; Handler, T.; Hart, E.L.; Read, K.; Ward, B.F.L.
1992-10-01
Work continues on strange particle production in weak interactions using data from a high-energy neutrino exposure in a freon bubble chamber. Meson photoproduction has also consumed considerable effort. Detector research and development activities have been carried out
Elementary particle interactions
International Nuclear Information System (INIS)
Bugg, W.M.; Condo, G.T.; Handler, T.; Hart, E.L.; Ward, B.F.L.; Close, F.E.; Christophorou, L.G.
1990-10-01
This report discusses freon bubble chamber experiments exposed to μ + and neutrinos, photon-proton interactions; shower counter simulations; SLD detectors at the Stanford Linear Collider, and the detectors at the Superconducting Super Collider; elementary particle interactions; physical properties of dielectric materials used in High Energy Physics detectors; and Nuclear Physics
Theory of particle interactions
International Nuclear Information System (INIS)
Belokurov, V.V.; Shirkov, D.V.
1986-01-01
Development and modern state of the theory of elementary particle interactions is described. The main aim of the paper is to give a picture of quantum field theory development in the form easily available for physicists not occupied in this field of science. Besides the outline of chronological development of main representations, the description of renormalization and renorm-groups, gauge theories, models of electro-weak interactions and quantum chromodynamics, the latest investigations related to joining all interactions and supersymmetries is given
Interactive Terascale Particle Visualization
Ellsworth, David; Green, Bryan; Moran, Patrick
2004-01-01
This paper describes the methods used to produce an interactive visualization of a 2 TB computational fluid dynamics (CFD) data set using particle tracing (streaklines). We use the method introduced by Bruckschen et al. [2001] that pre-computes a large number of particles, stores them on disk using a space-filling curve ordering that minimizes seeks, and then retrieves and displays the particles according to the user's command. We describe how the particle computation can be performed using a PC cluster, how the algorithm can be adapted to work with a multi-block curvilinear mesh, and how the out-of-core visualization can be scaled to 296 billion particles while still achieving interactive performance on PG hardware. Compared to the earlier work, our data set size and total number of particles are an order of magnitude larger. We also describe a new compression technique that allows the lossless compression of the particles by 41% and speeds the particle retrieval by about 30%.
Enhancement of particle-wave energy exchange by resonance sweeping
International Nuclear Information System (INIS)
Berk, H.L.; Breizman, B.N.
1995-10-01
It is shown that as the resonance condition of the particle-wave interaction is varied adiabatically, that the particles trapped in the wave will form phase space holes or clumps that can enhance the particle-wave energy exchange. This mechanism can cause much larger saturation levels of instabilities, and even allow the free energy associated with instability, to be tapped in a system that is linearly stable due to background dissipation
Approximate scattering wave functions for few-particle continua
International Nuclear Information System (INIS)
Briggs, J.S.
1990-01-01
An operator identity which allows the wave operator for N particles interacting pairwise to be expanded as products of operators in which fewer than N particles interact is given. This identity is used to derive appproximate scattering wave functions for N-particle continua that avoid certain difficulties associated with Faddeev-type expansions. For example, a derivation is given of a scattering wave function used successfully recently to describe the three-particle continuum occurring in the electron impact ionization of the hydrogen atom
Capture of charged particles by transverse electromagnetic waves
Energy Technology Data Exchange (ETDEWEB)
Davydovskii, V Ya; Sapogin, V G; Ukolov, A S
1975-01-01
An estimate is made of the maximum possible number of resonance particles interacting with a plane, transverse electromagnetic wave. The estimate is obtained by means of a distribution function, which is expressed in terms of the integrals of motion of the particles in the wave. Values of proton fluxes accelerated by an amplitude-modulated wave in the solar corona coincide with those observed during bursts of sporadic radioemission. (SJR)
New particles and interactions
International Nuclear Information System (INIS)
Gilman, F.J.; Grannis, P.D.
1984-04-01
The Working Group on New Particles and Interactions met as a whole at the beginning and at the end of the Workshop. However, much of what was accomplished was done in five subgroups. These were devoted to: (1) new quarks and leptons; (2) technicolor; (3) supersymmetry; (4) rare decays and CP; and (5) substructure of quarks and leptons. Other aspects of new particles, e.g., Higgs, W', Z', fell to the Electroweak Working Group to consider. The central question of this Workshop of comparing anti pp (with L = 10 32 /cm 2 -sec) with pp (with L = 10 33 /cm 2 -sec) colliders carried through to all these subgroups. In addition there were several other aspects of hadron colliders which were considered: what does an increase in √s gain in cross section and resultant sensitivity to new physics versus an increase in luminosity; will polarized beams or the use of asymmetries be essential in finding new interactions; where and at what level do rate limitations due to triggering or detection systems play a role; and how and where will the detection of particles with short, but detectable, lifetimes be important. 25 references
PARTICLE SCATTERING OFF OF RIGHT-HANDED DISPERSIVE WAVES
Energy Technology Data Exchange (ETDEWEB)
Schreiner, C.; Kilian, P.; Spanier, F., E-mail: cschreiner@astro.uni-wuerzburg.de [Centre for Space Research, North-West University, 2520 Potchefstroom (South Africa)
2017-01-10
Resonant scattering of fast particles off low frequency plasma waves is a major process determining transport characteristics of energetic particles in the heliosphere and contributing to their acceleration. Usually, only Alfvén waves are considered for this process, although dispersive waves are also present throughout the heliosphere. We investigate resonant interaction of energetic electrons with dispersive, right-handed waves. For the interaction of particles and a single wave a variable transformation into the rest frame of the wave can be performed. Here, well-established analytic models derived in the framework of magnetostatic quasi-linear theory can be used as a reference to validate simulation results. However, this approach fails as soon as several dispersive waves are involved. Based on analytic solutions modeling the scattering amplitude in the magnetostatic limit, we present an approach to modify these equations for use in the plasma frame. Thereby we aim at a description of particle scattering in the presence of several waves. A particle-in-cell code is employed to study wave–particle scattering on a micro-physically correct level and to test the modified model equations. We investigate the interactions of electrons at different energies (from 1 keV to 1 MeV) and right-handed waves with various amplitudes. Differences between model and simulation arise in the case of high amplitudes or several waves. Analyzing the trajectories of single particles we find no microscopic diffusion in the case of a single plasma wave, although a broadening of the particle distribution can be observed.
Nonlinear dynamics of resonant electrons interacting with coherent Langmuir waves
Tobita, Miwa; Omura, Yoshiharu
2018-03-01
We study the nonlinear dynamics of resonant particles interacting with coherent waves in space plasmas. Magnetospheric plasma waves such as whistler-mode chorus, electromagnetic ion cyclotron waves, and hiss emissions contain coherent wave structures with various discrete frequencies. Although these waves are electromagnetic, their interaction with resonant particles can be approximated by equations of motion for a charged particle in a one-dimensional electrostatic wave. The equations are expressed in the form of nonlinear pendulum equations. We perform test particle simulations of electrons in an electrostatic model with Langmuir waves and a non-oscillatory electric field. We solve equations of motion and study the dynamics of particles with different values of inhomogeneity factor S defined as a ratio of the non-oscillatory electric field intensity to the wave amplitude. The simulation results demonstrate deceleration/acceleration, thermalization, and trapping of particles through resonance with a single wave, two waves, and multiple waves. For two-wave and multiple-wave cases, we describe the wave-particle interaction as either coherent or incoherent based on the probability of nonlinear trapping.
Shock Interaction with Random Spherical Particle Beds
Neal, Chris; Mehta, Yash; Salari, Kambiz; Jackson, Thomas L.; Balachandar, S. "Bala"; Thakur, Siddharth
2016-11-01
In this talk we present results on fully resolved simulations of shock interaction with randomly distributed bed of particles. Multiple simulations were carried out by varying the number of particles to isolate the effect of volume fraction. Major focus of these simulations was to understand 1) the effect of the shockwave and volume fraction on the forces experienced by the particles, 2) the effect of particles on the shock wave, and 3) fluid mediated particle-particle interactions. Peak drag force for particles at different volume fractions show a downward trend as the depth of the bed increased. This can be attributed to dissipation of energy as the shockwave travels through the bed of particles. One of the fascinating observations from these simulations was the fluctuations in different quantities due to presence of multiple particles and their random distribution. These are large simulations with hundreds of particles resulting in large amount of data. We present statistical analysis of the data and make relevant observations. Average pressure in the computational domain is computed to characterize the strengths of the reflected and transmitted waves. We also present flow field contour plots to support our observations. U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, under Contract No. DE-NA0002378.
Wave-Particle Dualism in Action
Schleich, Wolfgang P.
The wave-particle dualism, that is the wave nature of particles and the particle nature of light together with the uncertainty relation of Werner Heisenberg and the principle of complementarity formulated by Niels Bohr represent pillars of quantum theory. We provide an introduction into these fascinating yet strange aspects of the microscopic world and summarize key experiments confirming these concepts so alien to our daily life.
Wave Interactions and Fluid Flows
Craik, Alex D. D.
1988-07-01
This up-to-date and comprehensive account of theory and experiment on wave-interaction phenomena covers fluids both at rest and in their shear flows. It includes, on the one hand, water waves, internal waves, and their evolution, interaction, and associated wave-driven means flow and, on the other hand, phenomena on nonlinear hydrodynamic stability, especially those leading to the onset of turbulence. This study provide a particularly valuable bridge between these two similar, yet different, classes of phenomena. It will be of value to oceanographers, meteorologists, and those working in fluid mechanics, atmospheric and planetary physics, plasma physics, aeronautics, and geophysical and astrophysical fluid dynamics.
Nonlinear wave equation with intrinsic wave particle dualism
International Nuclear Information System (INIS)
Klein, J.J.
1976-01-01
A nonlinear wave equation derived from the sine-Gordon equation is shown to possess a variety of solutions, the most interesting of which is a solution that describes a wave packet travelling with velocity usub(e) modulating a carrier wave travelling with velocity usub(c). The envelop and carrier wave speeds agree precisely with the group and phase velocities found by de Broglie for matter waves. No spreading is exhibited by the soliton, so that it behaves exactly like a particle in classical mechanics. Moreover, the classically computed energy E of the disturbance turns out to be exactly equal to the frequency ω of the carrier wave, so that the Planck relation is automatically satisfied without postulating a particle-wave dualism. (author)
Interaction of gravitational plane waves
International Nuclear Information System (INIS)
Ferrari, V.
1988-01-01
The mathematical theory of colliding, infinite-fronted, plane gravitational waves is presented. The process of focusing, the creation of singularities and horizons, due to the interaction, and the lens effect due to a beam-like gravitational wave are discussed
Nonlinear particle-wave kinetics in weakly unstable plasmas
International Nuclear Information System (INIS)
Breizman, B.N.; Berk, H.L.; Pekker, M.S.
1996-01-01
With the motivation to address the behavior of the fusion produced alpha particles in a thermonuclear reactor, a theory is developed for predicting the wave saturation levels and particle transport in weakly unstable systems with a discrete number of modes in the presence of energetic particle sources and sinks. Conditions are established for either steady state or bursting nonlinear scenarios when several modes are excited for cases where there is and there is not resonance overlap. Depending on parameters, the particles can undergo benign relaxation, with only a small fraction of the available free energy released to waves and with no global transport, or the particles can experience rapid global transport caused by a substantial conversion of their free energy into wave energy. When the resonance condition of the particle-wave interaction is varied adiabatically, the particles trapped in a wave are found to form phase space holes or clumps that enhance the particle-wave energy exchange. This mechanism, which has been experimentally observed when there is frequency chirping, causes increased saturation levels of instabilities. If resonance sweeping is imposed externally, the particle free energy can even be tapped in stable systems where background dissipation suppresses linear instability. Externally applied resonance sweeping can be important for alpha particle energy channeling, as well as for understanding fishbone and some Alfven wave instability experiments. Near instability threshold, that is when the destabilizing drive just exceeds the background dissipation, a more sophisticated analysis is developed to predict the correct saturation. To leading order, this problem reduces to an integral equation for the wave amplitude with a temporally non local cubic term. This equation has a self-similar solution that blows-up in a finite time
Stochastic particle acceleration by plasma waves in AGN jets
International Nuclear Information System (INIS)
Li, Hui; Colgate, S.A.; Miller, J.A.
1997-01-01
The free energy stored in the stressed magnetic fields in AGN jets could be dissipated via generating turbulent plasma waves. The authors review several key wave-particle resonant interactions and point out the importance of a broad wave spectrum. Under several idealized assumptions, they show that the transit-time damping process can accelerate electrons to TeV energies in an AGN jet environment, and present a preliminary calculation on the evolution of plasma wave, electron, and photon distributions. The authors especially emphasize several open questions on particle acceleration by waves, and argue that a plausible scenario is to energize electrons out of the thermal background via transit-time damping and further accelerate them by the parallel propagating right-handed waves
Particle acceleration by plasma waves
International Nuclear Information System (INIS)
Joshi, C.
2006-01-01
In an advanced particle accelerator particles are driven near by light velocity through ionized gas. Such plasma devices are compact, cost efficient and usable in many fields. Examples are given in detail. (GL)
Distorted wave method in reactions with composite particles
International Nuclear Information System (INIS)
Zelenskaya, N.S.; Teplov, I.B.
1980-01-01
The work deals with the distorbed wave method with a finite radius of interaction (DWBAFR) as applied to quantitative analysis of direct nuclear reactions with composite particles (including heavy ions) considering the reaction mechanisms other than the cluster stripping mechanism, in particular the exchange processes. The accurate equations of the distorbed-wave method in the three-body problem and the general formula dor calculating differential cross-sections of arbitrary binary reactions by DWBAFR are presented. Accurate and approximate methods allowing for finite interaction radius are discussed. Two main versions of exact account of recoil effects: separation of variables in wave functions of relative motion of particles and in interaction potentials and separation of variables in distorted waves are analysed. Given is a characteristic of the known calculated programs approximately and exactly taking account of recoil effects for direct and exchange processes [ru
Acoustic interaction forces between small particles in an ideal fluid
DEFF Research Database (Denmark)
Silva, Glauber T.; Bruus, Henrik
2014-01-01
We present a theoretical expression for the acoustic interaction force between small spherical particles suspended in an ideal fluid exposed to an external acoustic wave. The acoustic interaction force is the part of the acoustic radiation force on one given particle involving the scattered waves...... from the other particles. The particles, either compressible liquid droplets or elastic microspheres, are considered to be much smaller than the acoustic wavelength. In this so-called Rayleigh limit, the acoustic interaction forces between the particles are well approximated by gradients of pair...
Stochastic interaction between TAE and alpha particles
International Nuclear Information System (INIS)
Krlin, L.; Pavlo, P.; Malijevsky, I.
1996-01-01
The interaction of toroidicity-induced Alfven eigenmodes with thermonuclear alpha particles in the intrinsic stochasticity regime was investigated based on the numerical integration of the equation of motion of alpha particles in the tokamak. The first results obtained for the ITER parameters and moderate wave amplitudes indicate that the stochasticity is highest in the trapped/passing boundary region, where the alpha particles jump stochastically between the two regimes with an appreciable radial excursion (about 0.5 m amplitudes). A similar chaotic behavior was also found for substantially lower energies (about 350 keV). 7 figs., 15 refs
Wave-particle dualism of spiral waves dynamics.
Biktasheva, I V; Biktashev, V N
2003-02-01
We demonstrate and explain a wave-particle dualism of such classical macroscopic phenomena as spiral waves in active media. That means although spiral waves appear as nonlocal processes involving the whole medium, they respond to small perturbations as effectively localized entities. The dualism appears as an emergent property of a nonlinear field and is mathematically expressed in terms of the spiral waves response functions, which are essentially nonzero only in the vicinity of the spiral wave core. Knowledge of the response functions allows quantitatively accurate prediction of the spiral wave drift due to small perturbations of any nature, which makes them as fundamental characteristics for spiral waves as mass is for the condensed matter.
Nonlinear interaction of waves in an inhomogeneous plasma
International Nuclear Information System (INIS)
Istomin, Ya.N.
1988-01-01
Nonlinear wave processes in a weakly inhomogeneous plasma are considered. A quasilinear equation is derived which takes into account the effect of the waves on resonance particles, provided that the inhomogeneity appreciably affects the nature of the resonance interaction. Three-wave interaction is investigated under the same conditions. As an example, the nonlinear interaction in a relativistic plasma moving along a strong curvilinear magnetic field is considered
A Statistical Model for Soliton Particle Interaction in Plasmas
DEFF Research Database (Denmark)
Dysthe, K. B.; Pécseli, Hans; Truelsen, J.
1986-01-01
A statistical model for soliton-particle interaction is presented. A master equation is derived for the time evolution of the particle velocity distribution as induced by resonant interaction with Korteweg-de Vries solitons. The detailed energy balance during the interaction subsequently determines...... the evolution of the soliton amplitude distribution. The analysis applies equally well for weakly nonlinear plasma waves in a strongly magnetized waveguide, or for ion acoustic waves propagating in one-dimensional systems....
Particle acceleration and shock wave structure
International Nuclear Information System (INIS)
DRURY, L.O'C.
1989-01-01
A significant determinant in the large-scale structure and evolution of strong collisionless shocks under astrophysical conditions is probably the acceleration of charged particles. The reaction of these particles on the dynamical structure of the shock wave is discussed both theoretically and in the light of recent numerical calculations. Astrophysical implications for the evolution of supernova remnants, are considered. (author). 15 refs
Interaction of langmuir and ion acoustic waves
International Nuclear Information System (INIS)
Lee, Hee Jae
1991-01-01
Interaction of Langmuir and ion acoustic waves in a plasma is described by Landau-Ginzburg type of equation when the group velocity of the Langmuir wave is equal to the wave velocity of ion acoustic wave. (Author)
Hunting for Dark Particles with Gravitational Waves
Giudice, Gian F.; Urbano, Alfredo
2016-01-01
The LIGO observation of gravitational waves from a binary black hole merger has begun a new era in fundamental physics. If new dark sector particles, be they bosons or fermions, can coalesce into exotic compact objects (ECOs) of astronomical size, then the first evidence for such objects, and their underlying microphysical description, may arise in gravitational wave observations. In this work we study how the macroscopic properties of ECOs are related to their microscopic properties, such as dark particle mass and couplings. We then demonstrate the smoking gun exotic signatures that would provide observational evidence for ECOs, and hence new particles, in terrestrial gravitational wave observatories. Finally, we discuss how gravitational waves can test a core concept in general relativity: Hawking's area theorem.
Hunting for Dark Particles with Gravitational Waves
Giudice, Gian F.
2017-12-01
The LIGO observation of gravitational waves from a binary black hole merger has begun a new era in fundamental physics. If new dark sector particles, be they bosons or fermions, can coalesce into exotic compact objects (ECOs) of astronomical size, then the first evidence for such objects, and their underlying microphysical description, may arise in gravitational wave observations. In this work we study how the macroscopic properties of ECOs are related to their microscopic properties, such as dark particle mass and couplings. We then demonstrate the smoking gun exotic signatures that would provide observational evidence for ECOs, and hence new particles, in terrestrial gravitational wave observatories. Finally, we discuss how gravitational waves can test a core concept in general relativity: Hawking's area theorem.
Hunting for dark particles with gravitational waves
Energy Technology Data Exchange (ETDEWEB)
Giudice, Gian F.; McCullough, Matthew; Urbano, Alfredo [CERN, Theoretical Physics Department,Geneva (Switzerland)
2016-10-03
The LIGO observation of gravitational waves from a binary black hole merger has begun a new era in fundamental physics. If new dark sector particles, be they bosons or fermions, can coalesce into exotic compact objects (ECOs) of astronomical size, then the first evidence for such objects, and their underlying microphysical description, may arise in gravitational wave observations. In this work we study how the macroscopic properties of ECOs are related to their microscopic properties, such as dark particle mass and couplings. We then demonstrate the smoking gun exotic signatures that would provide observational evidence for ECOs, and hence new particles, in terrestrial gravitational wave observatories. Finally, we discuss how gravitational waves can test a core concept in general relativity: Hawking’s area theorem.
Hunting for dark particles with gravitational waves
International Nuclear Information System (INIS)
Giudice, Gian F.; McCullough, Matthew; Urbano, Alfredo
2016-01-01
The LIGO observation of gravitational waves from a binary black hole merger has begun a new era in fundamental physics. If new dark sector particles, be they bosons or fermions, can coalesce into exotic compact objects (ECOs) of astronomical size, then the first evidence for such objects, and their underlying microphysical description, may arise in gravitational wave observations. In this work we study how the macroscopic properties of ECOs are related to their microscopic properties, such as dark particle mass and couplings. We then demonstrate the smoking gun exotic signatures that would provide observational evidence for ECOs, and hence new particles, in terrestrial gravitational wave observatories. Finally, we discuss how gravitational waves can test a core concept in general relativity: Hawking’s area theorem.
Determination of particle size distributions from acoustic wave propagation measurements
International Nuclear Information System (INIS)
Spelt, P.D.; Norato, M.A.; Sangani, A.S.; Tavlarides, L.L.
1999-01-01
The wave equations for the interior and exterior of the particles are ensemble averaged and combined with an analysis by Allegra and Hawley [J. Acoust. Soc. Am. 51, 1545 (1972)] for the interaction of a single particle with the incident wave to determine the phase speed and attenuation of sound waves propagating through dilute slurries. The theory is shown to compare very well with the measured attenuation. The inverse problem, i.e., the problem of determining the particle size distribution given the attenuation as a function of frequency, is examined using regularization techniques that have been successful for bubbly liquids. It is shown that, unlike the bubbly liquids, the success of solving the inverse problem is limited since it depends strongly on the nature of particles and the frequency range used in inverse calculations. copyright 1999 American Institute of Physics
Linear interaction of gravitational waves
International Nuclear Information System (INIS)
Ciubotariu, C.D.
1992-01-01
Starting with the linearized Einstein equations written in the same form as Maxwell equations, a damping term is found in the wave equation. The analogy with the propagation of the electromagnetic wave in ohmic media is obvious if we introduce an 'ohmic relation' for gravitational interaction. The possibility of the amplification of gravitational waves by a suitable choice of the velocity field of a dust ('dust with negative viscosity'), for example by the use of the free-electron laser principle, is indicated. (Author)
Cooling a birth distribution of α-particles in a tokamak with waves
International Nuclear Information System (INIS)
Herrmann, M.C.; Fisch, N.J.
1996-01-01
Alpha particles, the byproducts of the DT reaction in tokamak fusion reactor, might be cooled through interactions with waves. Numerical simulations employing two waves,one with frequency about the alpha cyclotron frequency, and one at much lower frequency, show the existence of parameter regimes where more than half of the α-particle power can be diverted to the waves
Path integral for Dirac particle in plane wave field
International Nuclear Information System (INIS)
Zeggari, S.; Boudjedaa, T.; Chetouani, L.
2001-01-01
The problem of a relativistic spinning particle in interaction with an electromagnetic plane wave field is treated via path integrals. The dynamics of the spin of the particle is described using the supersymmetric action proposed by Fradkin and Gitman. The problem has been solved by using two identities, one bosonic and the other fermionic, which are related directly to the classical equations of motion. The exact expression of the relative Green's function is given and the result agrees with those of the literature. Further, the suitably normalized wave functions are also extracted. (orig.)
Path integral for Dirac particle in plane wave field
Energy Technology Data Exchange (ETDEWEB)
Zeggari, S.; Boudjedaa, T.; Chetouani, L. [Mentouri Univ., Constantine (Algeria). Dept. of Physique
2001-10-01
The problem of a relativistic spinning particle in interaction with an electromagnetic plane wave field is treated via path integrals. The dynamics of the spin of the particle is described using the supersymmetric action proposed by Fradkin and Gitman. The problem has been solved by using two identities, one bosonic and the other fermionic, which are related directly to the classical equations of motion. The exact expression of the relative Green's function is given and the result agrees with those of the literature. Further, the suitably normalized wave functions are also extracted. (orig.)
Directory of Open Access Journals (Sweden)
Petrov Yuri V.
2017-01-01
Full Text Available The bounce-average (BA finite-difference Fokker-Planck (FP code CQL3D [1,2] now includes the essential physics to describe the RF heating of Finite-Orbit-Width (FOW ions in tokamaks. The FP equation is reformulated in terms of Constants-Of-Motion coordinates, which we select to be particle speed, pitch angle, and major radius on the equatorial plane thus obtaining the distribution function directly at this location. Full-orbit, low collisionality neoclassical radial transport emerges from averaging the local friction and diffusion coefficients along guiding center orbits. Similarly, the BA of local quasilinear RF diffusion terms gives rise to additional radial transport. The local RF electric field components needed for the BA operator are usually obtained by a ray-tracing code, such as GENRAY, or in conjunction with full-wave codes. As a new, practical application, the CQL3D-FOW version is used for simulation of alpha-particle heating by high-harmonic waves in ITER. Coupling of high harmonic or helicon fast waves power to electrons is a promising current drive (CD scenario for high beta plasmas. However, the efficiency of current drive can be diminished by parasitic channeling of RF power into fast ions, such as alphas, through finite Larmor-radius effects. We investigate possibilities to reduce the fast ion heating in CD scenarios.
Maxwell and the classical wave particle dualism.
Mendonça, J T
2008-05-28
Maxwell's equations are one of the greatest theoretical achievements in physics of all times. They have survived three successive theoretical revolutions, associated with the advent of relativity, quantum mechanics and modern quantum field theory. In particular, they provide the theoretical framework for the understanding of the classical wave particle dualism.
Coulomb interactions in particle beams
International Nuclear Information System (INIS)
Jansen, G.H.
1988-01-01
This thesis presents a theoretical description of the Coulomb interaction between identical charged particles (electrons or ions) in focussed beam. The charge-density effects as well as the various statistical interaction effects, known as the Boersch effect and the 'trajectory displacement effect', are treated. An introductory literature survey is presented from which the large differences in theoretical approach appear. Subsequently the methods are investigated which are used in studies of comparable problems in plasma physics and stellar dynamics. These turn out to be applicable to particle beams only for certain extreme conditions. The approach finally chosen in this study is twofold. On the one hand use is made of a semi-analytical model in which the statistical and dynamical aspects of the N-particle problem are reduced to two-particle problem. This model results in a number of explicit equations in the experimental parameters, with ties of the beam can be determined directly. On the other hand use has been made of a purely numerical Monte Carlo model in which the kinematical equations of an ensemble interacting particles with 'at random' chosen starting conditions are solved exactly. This model does not lead to general expressions, but yields a specific numerical prediction for each simulated experimental situation. The results of both models appear to agree well mutually. This yields a consistent theory which complements the existing knowledge of particle optics and which allow the description of systems in which the interaction between particles can not be neglected. The predictions of this theory are qualitatively and quantitatively compared with those from some other models, recently reported in literature. (author). 256 refs.; 114 figs.; 1180 schemes; 5 tabs
Wave-particle dualism in matter wave interferometry
International Nuclear Information System (INIS)
Rauch, H.
1984-01-01
Neutron interferometry is a unique tool for investigations in the field of particle-wave dualism because massive elementary particles behave like waves within the interferometer. The invention of perfect crystal neutron interferometers providing widely separated coherent beams stimulated a great variety of experiments with matter waves in the field of basic quantum mechanics. The phase of the spatial and spinor wave function become a measurable quantity and can be influenced individually. High degrees of coherence and high order interferences have been observed by this technique. The 4π-symmetry of a spinor wave function and the mutual modulation of nuclear and magnetic phase shifts have been measured in the past. Recent experiments dealt with polarized neutron beams, which are handled to realize the spin-superposition of two oppositionally polarized subbeams resulting in final polarization perpendicular to both initial beam polarizations. The different action on the coherent beams of static and dynamic flippers have been visualized. Monolithic multicrystal arrangements in Laue position can also be used to achieve an extremely high energy (10 -9 eV) or angular resolution (0.001 sec of arc). This feature is based on the Pendelloesung interference within the perfect crystal. A transverse coherence length up to 6.5 mm is deduced from single slit diffraction experiments. (Auth.)
Effects of aerodynamic particle interaction in turbulent non-dilute particle-laden flow
DEFF Research Database (Denmark)
Salewski, Mirko; Fuchs, Laszlo
2008-01-01
Aerodynamic four-way coupling models are necessary to handle two-phase flows with a dispersed phase in regimes in which the particles are neither dilute enough to neglect particle interaction nor dense enough to bring the mixture to equilibrium. We include an aerodynamic particle interaction model...... levels in the flow then decrease. The impact of the stochastic particle description on the four-way coupling model is shown to be relatively small. If particles are also allowed to break up according to a wave breakup model, the particles become polydisperse. An ad hoc model for handling polydisperse...
Light weakly interacting massive particles
Gelmini, Graciela B.
2017-08-01
Light weakly interacting massive particles (WIMPs) are dark matter particle candidates with weak scale interaction with the known particles, and mass in the GeV to tens of GeV range. Hints of light WIMPs have appeared in several dark matter searches in the last decade. The unprecedented possible coincidence into tantalizingly close regions of mass and cross section of four separate direct detection experimental hints and a potential indirect detection signal in gamma rays from the galactic center, aroused considerable interest in our field. Even if these hints did not so far result in a discovery, they have had a significant impact in our field. Here we review the evidence for and against light WIMPs as dark matter candidates and discuss future relevant experiments and observations.
The theory of particle interactions
International Nuclear Information System (INIS)
Belokurov, V.V.; Shirkov, D.V.
1991-01-01
The Theory of Particle Interactions introduces students and physicists to the chronological development, concepts, main methods, and results of modern quantum field theory -- the most fundamental, abstract, and mathematical branch of theoretical physics. Belokurov and Shirkov, two prominent Soviet theoretical physicists, carefully describe the many facets of modern quantum theory including: renormalization theory and renormalization group; gauge theories and spontaneous symmetry breaking; the electroweak interaction theory and quantum chromodynamics; the schemes of the unification of the fundamental interactions; and super-symmetry and super-strings. The authors use a minimum of mathematical concepts and equations in describing the historical development, the current status, and the role of quantum field theory in modern theoretical physics. Because readers will be able to comprehend the main concepts of modern quantum theory without having to master its rather difficult apparatus, The Theory of Particle Interactions is ideal for those who seek a conceptual understanding of the subject. Students, physicists, mathematicians, and theoreticians involved in astrophysics, cosmology, and nuclear physics, as well as those interested in the philosophy and history of natural sciences will find The Theory of Particle Interactions invaluable and an important addition to their reading list
Particle transport model sensitivity on wave-induced processes
Staneva, Joanna; Ricker, Marcel; Krüger, Oliver; Breivik, Oyvind; Stanev, Emil; Schrum, Corinna
2017-04-01
Different effects of wind waves on the hydrodynamics in the North Sea are investigated using a coupled wave (WAM) and circulation (NEMO) model system. The terms accounting for the wave-current interaction are: the Stokes-Coriolis force, the sea-state dependent momentum and energy flux. The role of the different Stokes drift parameterizations is investigated using a particle-drift model. Those particles can be considered as simple representations of either oil fractions, or fish larvae. In the ocean circulation models the momentum flux from the atmosphere, which is related to the wind speed, is passed directly to the ocean and this is controlled by the drag coefficient. However, in the real ocean, the waves play also the role of a reservoir for momentum and energy because different amounts of the momentum flux from the atmosphere is taken up by the waves. In the coupled model system the momentum transferred into the ocean model is estimated as the fraction of the total flux that goes directly to the currents plus the momentum lost from wave dissipation. Additionally, we demonstrate that the wave-induced Stokes-Coriolis force leads to a deflection of the current. During the extreme events the Stokes velocity is comparable in magnitude to the current velocity. The resulting wave-induced drift is crucial for the transport of particles in the upper ocean. The performed sensitivity analyses demonstrate that the model skill depends on the chosen processes. The results are validated using surface drifters, ADCP, HF radar data and other in-situ measurements in different regions of the North Sea with a focus on the coastal areas. The using of a coupled model system reveals that the newly introduced wave effects are important for the drift-model performance, especially during extremes. Those effects cannot be neglected by search and rescue, oil-spill, transport of biological material, or larva drift modelling.
Particle separation by phase modulated surface acoustic waves.
Simon, Gergely; Andrade, Marco A B; Reboud, Julien; Marques-Hueso, Jose; Desmulliez, Marc P Y; Cooper, Jonathan M; Riehle, Mathis O; Bernassau, Anne L
2017-09-01
High efficiency isolation of cells or particles from a heterogeneous mixture is a critical processing step in lab-on-a-chip devices. Acoustic techniques offer contactless and label-free manipulation, preserve viability of biological cells, and provide versatility as the applied electrical signal can be adapted to various scenarios. Conventional acoustic separation methods use time-of-flight and achieve separation up to distances of quarter wavelength with limited separation power due to slow gradients in the force. The method proposed here allows separation by half of the wavelength and can be extended by repeating the modulation pattern and can ensure maximum force acting on the particles. In this work, we propose an optimised phase modulation scheme for particle separation in a surface acoustic wave microfluidic device. An expression for the acoustic radiation force arising from the interaction between acoustic waves in the fluid was derived. We demonstrated, for the first time, that the expression of the acoustic radiation force differs in surface acoustic wave and bulk devices, due to the presence of a geometric scaling factor. Two phase modulation schemes are investigated theoretically and experimentally. Theoretical findings were experimentally validated for different mixtures of polystyrene particles confirming that the method offers high selectivity. A Monte-Carlo simulation enabled us to assess performance in real situations, including the effects of particle size variation and non-uniform acoustic field on sorting efficiency and purity, validating the ability to separate particles with high purity and high resolution.
Coulomb Final State Interactions for Gaussian Wave Packets
Wiedemann, Urs Achim; Heinz, Ulrich W
1999-01-01
Two-particle like-sign and unlike-sign correlations including Coulomb final state interactions are calculated for Gaussian wave packets emitted from a Gaussian source. We show that the width of the wave packets can be fully absorbed into the spatial and momentum space widths of an effective emission function for plane wave states, and that Coulomb final state interaction effects are sensitive only to the latter, but not to the wave packet width itself. Results from analytical and numerical calculations are compared with recently published work by other authors.
Electromagnetic wave scattering by many small particles
International Nuclear Information System (INIS)
Ramm, A.G.
2007-01-01
Scattering of electromagnetic waves by many small particles of arbitrary shapes is reduced rigorously to solving linear algebraic system of equations bypassing the usual usage of integral equations. The matrix elements of this linear algebraic system have physical meaning. They are expressed in terms of the electric and magnetic polarizability tensors. Analytical formulas are given for calculation of these tensors with any desired accuracy for homogeneous bodies of arbitrary shapes. An idea to create a 'smart' material by embedding many small particles in a given region is formulated
Interacting electromagnetic waves in general relativity
International Nuclear Information System (INIS)
Griffiths, J.B.
1976-01-01
The problem is considered of finding exact solutions of the Einstein-Maxwell equations which describe the physical situation of two colliding and subsequently interacting electromagnetic waves. The general theory of relativity predicts a nonlinear interaction between electromagnetic waves. The situation is described using an approximate geometrical method, and a new exact solution describing two interacting electromagnetic waves is given. This describes waves emitted from two sources mutually focusing each other on the opposite source. (author)
Resonant Alfven wave instabilities driven by streaming fast particles
International Nuclear Information System (INIS)
Zachary, A.
1987-01-01
A plasma simulation code is used to study the resonant interactions between streaming ions and Alfven waves. The medium which supports the Alfven waves is treated as a single, one-dimensional, ideal MHD fluid, while the ions are treated as kinetic particles. The code is used to study three ion distributions: a cold beam; a monoenergetic shell; and a drifting distribution with a power-law dependence on momentum. These distributions represent: the field-aligned beams upstream of the earth's bow shock; the diffuse ions upstream of the bow shock; and the cosmic ray distribution function near a supernova remnant shock. 92 refs., 31 figs., 12 tabs
Particle production in a gravitational wave background
Jones, Preston; McDougall, Patrick; Singleton, Douglas
2017-03-01
We study the possibility that massless particles, such as photons, are produced by a gravitational wave. That such a process should occur is implied by tree-level Feynman diagrams such as two gravitons turning into two photons, i.e., g +g →γ +γ . Here we calculate the rate at which a gravitational wave creates a massless scalar field. This is done by placing the scalar field in the background of a plane gravitational wave and calculating the 4-current of the scalar field. Even in the vacuum limit of the scalar field it has a nonzero vacuum expectation value (similar to what occurs in the Higgs mechanism) and a nonzero current. We associate this with the production of scalar field quanta by the gravitational field. This effect has potential consequences for the attenuation of gravitational waves since the massless field is being produced at the expense of the gravitational field. This is related to the time-dependent Schwinger effect, but with the electric field replaced by the gravitational wave background and the electron/positron field quanta replaced by massless scalar "photons." Since the produced scalar quanta are massless there is no exponential suppression, as occurs in the Schwinger effect due to the electron mass.
Interaction between electromagnetic waves and plasma waves in motional plasma
International Nuclear Information System (INIS)
Chen, S. Y.; Gao, M.; Tang, C. J.; Peng, X. D.
2009-01-01
The electromagnetic wave (EM wave) behavior and the electromagnetic instability caused by the interaction between an EM wave and a plasma wave in motional plasma are studied. The dispersion relation of EM waves and the dielectric tensor of motional plasma are derived by magnetohydrodynamics, and the wave phenomenon in motional plasma is displayed. As a result, the electromagnetic instability, which is excited by the interaction between the EM waves and the plasma waves, is revealed. The mechanism of the instability is the coupling between high frequency electromagnetic field and the transverse electron oscillation derived from the deflection of longitudinal electron oscillation due to self-magnetic field. The present research is useful with regard to the new type of plasma radiation source, ion-focusing accelerator, and plasma diagnostic technique.
The interaction of fine particles with stranded oil
International Nuclear Information System (INIS)
Owens, E.H.
1999-01-01
The interaction of micron-sized mineral particles with stranded oil reduces its adhesion to solid surfaces, such as sediments or bedrock. The net result is the formation of stable, micron-sized, oil droplets that disperse into the water column. In turn, the increase in surface area makes the oil more available for biodegradation. Oil and Fine-particle Interaction ('OFI') can explain how oiled shorelines are cleaned naturally in the absence of wave action in very sheltered coastal environments. Fine-particle interaction can be accelerated during a spill response by relocating the oiled sediments into the surf zone. This has been achieved successfully on two occasions to date: the Tampa Bay response in Florida, and the Sea Empress operation in Wales. Sediment relocation also causes physical abrasion by the hydraulic action of waves so that the processes of fine-particle interaction and surf washing usually occur in combination on open coasts. (author)
The Interaction of Ocean Waves and Wind
Janssen, Peter
2004-10-01
Describing in detail the two-way interaction between wind and ocean waves, this book discusses ocean wave evolution in accordance with the energy balance equation. An extensive overview of nonlinear transfer is given, and the role of four-wave interactions in the generation of extreme events as well as the effects on ocean circulation is included. The volume will interest ocean wave modellers, physicists, applied mathematicians, and engineers.
Particle interaction with the deuteron
International Nuclear Information System (INIS)
Rosa, L.P.
1974-09-01
A study of the particle deuteron interactions at low, intermediate and high energies is presented. The differential cross section for pion deuteron scattering, near the 33 resonance, is calculated considering the Fermi motion and the off energy shell effects. We present formulae for the calculation of correction to the incoherent production cross section on deuteron arising from the multiple scattering and interference; we apply them to the case K + → K 0 π + between 1. and 5 Gev/c. is introduced. A relativistic correction to the double scattering Glauber formula and is done an application to the rho photoproduction on deuteron at high energies
Superparamagnetic relaxation of weakly interacting particles
DEFF Research Database (Denmark)
Mørup, Steen; Tronc, Elisabeth
1994-01-01
The influence of particle interactions on the superparamagnetic relaxation time has been studied by Mossbauer spectroscopy in samples of maghemite (gamma-Fe2O3) particles with different particle sizes and particle separations. It is found that the relaxation time decreases with decreasing particl...
Acceleration of low energy charged particles by gravitational waves
Energy Technology Data Exchange (ETDEWEB)
Voyatzis, G. [University of Thessaloniki, Department of Physics, 54124 Thessaloniki (Greece)]. E-mail: voyatzis@auth.gr; Vlahos, L. [University of Thessaloniki, Department of Physics, 54124 Thessaloniki (Greece); Ichtiaroglou, S. [University of Thessaloniki, Department of Physics, 54124 Thessaloniki (Greece); Papadopoulos, D. [University of Thessaloniki, Department of Physics, 54124 Thessaloniki (Greece)
2006-04-03
The acceleration of charged particles in the presence of a magnetic field and gravitational waves is under consideration. It is shown that the weak gravitational waves can cause the acceleration of low energy particles under appropriate conditions. Such conditions may be satisfied close to the source of the gravitational waves if the magnetized plasma is in a turbulent state.
Acceleration of low energy charged particles by gravitational waves
International Nuclear Information System (INIS)
Voyatzis, G.; Vlahos, L.; Ichtiaroglou, S.; Papadopoulos, D.
2006-01-01
The acceleration of charged particles in the presence of a magnetic field and gravitational waves is under consideration. It is shown that the weak gravitational waves can cause the acceleration of low energy particles under appropriate conditions. Such conditions may be satisfied close to the source of the gravitational waves if the magnetized plasma is in a turbulent state
Interacting particle systems on graphs
Sood, Vishal
In this dissertation, the dynamics of socially or biologically interacting populations are investigated. The individual members of the population are treated as particles that interact via links on a social or biological network represented as a graph. The effect of the structure of the graph on the properties of the interacting particle system is studied using statistical physics techniques. In the first chapter, the central concepts of graph theory and social and biological networks are presented. Next, interacting particle systems that are drawn from physics, mathematics and biology are discussed in the second chapter. In the third chapter, the random walk on a graph is studied. The mean time for a random walk to traverse between two arbitrary sites of a random graph is evaluated. Using an effective medium approximation it is found that the mean first-passage time between pairs of sites, as well as all moments of this first-passage time, are insensitive to the density of links in the graph. The inverse of the mean-first passage time varies non-monotonically with the density of links near the percolation transition of the random graph. Much of the behavior can be understood by simple heuristic arguments. Evolutionary dynamics, by which mutants overspread an otherwise uniform population on heterogeneous graphs, are studied in the fourth chapter. Such a process underlies' epidemic propagation, emergence of fads, social cooperation or invasion of an ecological niche by a new species. The first part of this chapter is devoted to neutral dynamics, in which the mutant genotype does not have a selective advantage over the resident genotype. The time to extinction of one of the two genotypes is derived. In the second part of this chapter, selective advantage or fitness is introduced such that the mutant genotype has a higher birth rate or a lower death rate. This selective advantage leads to a dynamical competition in which selection dominates for large populations
Porous models for wave-seabed interactions
Energy Technology Data Exchange (ETDEWEB)
Jeng, Dong-Sheng [Shanghai Jiaotong Univ., SH (China)
2013-02-01
Detailed discussion about the phenomenon of wave-seabed interactions. Novel models for wave-induced seabed response. Intensive theoretical derivations for wave-seabed interactions. Practical examples for engineering applications. ''Porous Models for Wave-seabed Interactions'' discusses the Phenomenon of wave-seabed interactions, which is a vital issue for coastal and geotechnical engineers involved in the design of foundations for marine structures such as pipelines, breakwaters, platforms, etc. The most important sections of this book will be the fully detailed theoretical models of wave-seabed interaction problem, which are particularly useful for postgraduate students and junior researchers entering the discipline of marine geotechnics and offshore engineering. This book also converts the research outcomes of theoretical studies to engineering applications that will provide front-line engineers with practical and effective tools in the assessment of seabed instability in engineering design.
Matter and Interactions: a particle physics perspective
Organtini, Giovanni
2011-01-01
In classical mechanics matter and fields are completely separated. Matter interacts with fields. For particle physicists this is not the case. Both matter and fields are represented by particles. Fundamental interactions are mediated by particles exchanged between matter particles. In this paper we explain why particle physicists believe in such a picture, introducing the technique of Feynman diagrams starting from very basic and popular analogies with classical mechanics, making the physics ...
Plasma particle drifts due to traveling waves with cyclotron frequencies
International Nuclear Information System (INIS)
Hatakeyama, Rikizo; Sato, Naoyuki; Sato, Noriyoshi
1991-01-01
A particle orbit theory yields that traveling waves with cyclotron frequencies give rise to charged particle drifts perpendicular both to the wave propagation and external magnetic field lines. The result is applicable to particle-flux control of magnetized plasmas. (author)
Shock waves in collective field theories for many particle systems
Energy Technology Data Exchange (ETDEWEB)
Oki, F; Saito, T [Kyoto Prefectural Univ. of Medicine (Japan); Shigemoto, K
1980-10-01
We find shock wave solutions to collective field equations for quantum mechanical many particle system. Importance of the existence of a ''tension'' working on the surface of the shock-wave front is pointed out.
Interaction of two walkers: wave-mediated energy and force.
Borghesi, Christian; Moukhtar, Julien; Labousse, Matthieu; Eddi, Antonin; Fort, Emmanuel; Couder, Yves
2014-12-01
A bouncing droplet, self-propelled by its interaction with the waves it generates, forms a classical wave-particle association called a "walker." Previous works have demonstrated that the dynamics of a single walker is driven by its global surface wave field that retains information on its past trajectory. Here we investigate the energy stored in this wave field for two coupled walkers and how it conveys an interaction between them. For this purpose, we characterize experimentally the "promenade modes" where two walkers are bound and propagate together. Their possible binding distances take discrete values, and the velocity of the pair depends on their mutual binding. The mean parallel motion can be either rectilinear or oscillating. The experimental results are recovered analytically with a simple theoretical framework. A relation between the kinetic energy of the droplets and the total energy of the standing waves is established.
Four-particle scattering with three-particle interactions
International Nuclear Information System (INIS)
Adhikari, S.K.
1979-01-01
The four-particle scattering formalism proposed independently by Alessandrini, by Mitra et al., by Rosenberg, and by Takahashi and Mishima is extended to include a possible three-particle interaction. The kernel of the new equations we get contain both two- and three-body connected parts and gets four-body connected after one iteration. On the other hand, the kernel of the original equations in the absence of three-particle interactions does not have a two-body connected part. We also write scattering equations for the transition operators connecting the two-body fragmentation channels. They are generalization of the Sloan equations in the presence of three-particle interactions. We indicate how to include approximately the effect of a weak three-particle interaction in a practical four-particle scattering calculation
The electrostatic interaction between interfacial colloidal particles
Hurd, A. J.
1985-11-01
The electrostatic interaction between charged, colloidal particles trapped at an air-water interface is considered using linearised Poisson-Boltzmann results for point particles. In addition to the expected screened-Coulomb contribution, which decays exponentially, an algebraic dipole-dipole interaction occurs that may account for long-range interactions in interfacial colloidal systems.
Mechanism of travelling-wave transport of particles
International Nuclear Information System (INIS)
Kawamoto, Hiroyuki; Seki, Kyogo; Kuromiya, Naoyuki
2006-01-01
Numerical and experimental investigations have been carried out on transport of particles in an electrostatic travelling field. A three-dimensional hard-sphere model of the distinct element method was developed to simulate the dynamics of particles. Forces applied to particles in the model were the Coulomb force, the dielectrophoresis force on polarized dipole particles in a non-uniform field, the image force, gravity and the air drag. Friction and repulsion between particle-particle and particle-conveyer were included in the model to replace initial conditions after mechanical contacts. Two kinds of experiments were performed to confirm the model. One was the measurement of charge of particles that is indispensable to determine the Coulomb force. Charge distribution was measured from the locus of free-fallen particles in a parallel electrostatic field. The averaged charge of the bulk particle was confirmed by measurement with a Faraday cage. The other experiment was measurements of the differential dynamics of particles on a conveyer consisting of parallel electrodes to which a four-phase travelling electrostatic wave was applied. Calculated results agreed with measurements, and the following characteristics were clarified. (1) The Coulomb force is the predominant force to drive particles compared with the other kinds of forces, (2) the direction of particle transport did not always coincide with that of the travelling wave but changed partially. It depended on the frequency of the travelling wave, the particle diameter and the electric field, (3) although some particles overtook the travelling wave at a very low frequency, the motion of particles was almost synchronized with the wave at the low frequency and (4) the transport of some particles was delayed to the wave at medium frequency; the majority of particles were transported backwards at high frequency and particles were not transported but only vibrated at very high frequency
Current fluctuations of interacting active Brownian particles
Pre, Trevor Grand; Limmer, David T.
2018-01-01
We derive the distribution function for particle currents for a system of interacting active Brownian particles in the long time limit using large deviation theory and a weighted many body expansion. We find the distribution is non-Gaussian, except in the limit of passive particles. The non-Gaussian fluctuations can be understood from the effective potential the particles experience when conditioned on a given current. This potential suppresses fluctuations of the particle's orientation, and ...
Three-wave interactions in a warm plasma
International Nuclear Information System (INIS)
Shivamoggi, B.K.
1983-01-01
The nonlinear resonance interactions between a Langmuir wave and two transverse electromagnetic waves (T-T-L) as well as between an ion-acoustic wave and two transverse electromagnetic waves (T-T-S) in a warm plasma are studied. It is shown that an incident transverse electromagnetic wave decays into another transverse electromagnetic wave and a Langmuir wave in a T-T-L wave-wave interaction as well as into another transverse electromagnetic wave and an ion-acoustic wave in a T-T-S wave-wave interaction. The growth rates of the daughter waves in the T-T-L wave-wave interaction are shown to be smaller than those of the daughter waves in the T-T-S wave-wave interaction. (M.F.W.)
Experimental investigation on particle-wall interactions
International Nuclear Information System (INIS)
Zeisel, H.; Dorfner, V.
1988-01-01
There is still a lack in the knowledge about many physical processes in two-phase flows and therefore their mathematical description for the modelling of two-phase flows by computer simulations still needs some improvement. One required information is the physical procedure of the momentum transfer between the phases themselves, such as particle-particle or particle-fluid interactions, and between the phases and the flow boundaries, such as particle-wall or fluid-wall interactions. The interaction between the two phases can be either a 'long-range' interference or a direct contact between both. For the particle-fluid two-phase flow system the interaction can be devided in particle-fluid, particle-particle and particle-boundary interactions. In this investigation the attention is drawn to the special case of a particle-wall interaction and its 'long-range' interference effect between the wall and a small particle which approaches the wall in normal direction. (orig./GL)
Theoretical Studies of Alfven Waves and Energetic Particle Physics in Fusion Plasmas
Energy Technology Data Exchange (ETDEWEB)
Chen, Liu [Univ. of California, Irvine, CA (United States)
2017-12-20
This report summarizes major theoretical findings in the linear as well as nonlinear physics of Alfvén waves and energetic particles in magnetically confined fusion plasmas. On the linear physics, a variational formulation, based on the separation of singular and regular spatial scales, for drift-Alfvén instabilities excited by energetic particles is established. This variational formulation is then applied to derive the general fishbone-like dispersion relations corresponding to the various Alfvén eigenmodes and energetic-particle modes. It is further employed to explore in depth the low-frequency Alfvén eigenmodes and demonstrate the non-perturbative nature of the energetic particles. On the nonlinear physics, new novel findings are obtained on both the nonlinear wave-wave interactions and nonlinear wave-energetic particle interactions. It is demonstrated that both the energetic particles and the fine radial mode structures could qualitatively affect the nonlinear evolution of Alfvén eigenmodes. Meanwhile, a theoretical approach based on the Dyson equation is developed to treat self-consistently the nonlinear interactions between Alfvén waves and energetic particles, and is then applied to explain simulation results of energetic-particle modes. Relevant list of journal publications on the above findings is also included.
Conservative numerical methods for solitary wave interactions
Energy Technology Data Exchange (ETDEWEB)
Duran, A; Lopez-Marcos, M A [Departamento de Matematica Aplicada y Computacion, Facultad de Ciencias, Universidad de Valladolid, Paseo del Prado de la Magdalena s/n, 47005 Valladolid (Spain)
2003-07-18
The purpose of this paper is to show the advantages that represent the use of numerical methods that preserve invariant quantities in the study of solitary wave interactions for the regularized long wave equation. It is shown that the so-called conservative methods are more appropriate to study the phenomenon and provide a dynamic point of view that allows us to estimate the changes in the parameters of the solitary waves after the collision.
Response of spherical gravitational wave antenna modes to high-energy cosmic ray particles
International Nuclear Information System (INIS)
Jr, R M Marinho; Magalhaes, N S; Aguiar, O D; Frajuca, C
2002-01-01
High-energy cosmic ray particles are expected to be a significant source of noise in resonant mass gravitational wave detectors close to the quantum limit. The spherical, fourth generation antennas have been designed to attain such a limit. In this work we will show how the energy of a cosmic ray particle interacting with such an antenna is distributed over its eigenmodes. We will then make some comments on the relevant consequences of such a distribution for gravitational wave detection
Response of spherical gravitational wave antenna modes to high-energy cosmic ray particles
Marinho, R M; Aguiar, O D; Frajuca, C
2002-01-01
High-energy cosmic ray particles are expected to be a significant source of noise in resonant mass gravitational wave detectors close to the quantum limit. The spherical, fourth generation antennas have been designed to attain such a limit. In this work we will show how the energy of a cosmic ray particle interacting with such an antenna is distributed over its eigenmodes. We will then make some comments on the relevant consequences of such a distribution for gravitational wave detection.
Resonant interaction of photons with gravitational waves
International Nuclear Information System (INIS)
Mendonca, J.T.; Drury, L. O'C.
2002-01-01
The interaction of photons with a low-amplitude gravitational wave propagating in a flat space-time is studied by using an exact model of photon dynamics. The existence of nearly resonant interactions between the photons and the gravitational waves, which can take place over large distances, can lead to a strong photon acceleration. Such a resonant mechanism can eventually be useful to build consistent new models of gamma-ray emitters
Charm and particle production in neutrino interactions
International Nuclear Information System (INIS)
Cazzoli, E.G.; Cnops, A.M.; Connolly, P.L.; Louttit, R.I.; Murtagh, M.J.; Palmer, R.B.; Samios, N.P.; Tso, T.T.; Williams, H.H.
1976-01-01
Ten strange particles were observed in a total of 1086 charged current neutrino interactions obtained in the analysis of 482,000 pictures taken in the Brookhaven Cryogenic 7' Bubble Chamber filled with hydrogen and deuterium. Details of these events are presented together with rates for associated strange particle and ΔS = +-ΔQ production in neutrino interactions
MECHANISM OF PARTICLE SUSPENSION OVER A SAND WAVE
芦田, 和男; 藤田, 正治; 向井, 健
1986-01-01
The characteristics of flow vary with space over sand waves. It is important to consider thisnouniformity in the modeling of motions of suspended particles, but few methods for calculationof suspended load have been proposed by consideration of this efects. In this paper mean velocityand turbulent strength of flow are discussed experimentally over a two-dimensinal sand wave andthe motion of suspended particle are formulated using these results and authors' theory on modelof particle motion ov...
Nonlinear interactions of counter-travelling waves
International Nuclear Information System (INIS)
Matsuuchi, Kazuo
1980-01-01
Nonlinear interactions between two waves travelling in opposite directions are investigated. When a nonlinear Klein-Gordon equation is adopted as a model equation, it is shown that such a wave system is governed by a simple set of equations for their complex amplitudes. Steady progressive waves governed by this set are investigated for various cases classified according to the signs of the coefficients. It is then found that one wave travelling in one direction appears from a certain point and the other travelling in the opposite direction has a constant amplitude from that point. This phenomenon may be regarded as a sort of reflection in spite of no rigid boundary. (author)
Shock wave interaction with turbulence: Pseudospectral simulations
International Nuclear Information System (INIS)
Buckingham, A.C.
1986-01-01
Shock waves amplify pre-existing turbulence. Shock tube and shock wave boundary layer interaction experiments provide qualitative confirmation. However, shock pressure, temperature, and rapid transit complicate direct measurement. Computational simulations supplement the experimental data base and help isolate the mechanisms responsible. Simulations and experiments, particularly under reflected shock wave conditions, significantly influence material mixing. In these pseudospectral Navier-Stokes simulations the shock wave is treated as either a moving (tracked or fitted) domain boundary. The simulations assist development of code mix models. Shock Mach number and pre-existing turbulence intensity initially emerge as key parameters. 20 refs., 8 figs
Resonant acceleration of alpha particles by ion cyclotron waves in the solar wind
Gomberoff, L.; Elgueta, R.
1991-06-01
Preferential acceleration of alpha particles interacting with left-hand polarized ion cyclotron waves is studied. It is shown that a small positive drift velocity between alpha particles and protons can lead to alpha particle velocities well in excess of the proton bulk velocity. During the acceleration process, which is assumed to take place at heliocentric distances less than 0.3 AU, the alpha particle drift velocity should exceed the proton bulk velocity, and then the gap which exists around the alpha particle gyrofrequency should disappear. It is also shown that for proton thermal anisotropies of the order of those observed in fast solar wind, the waves either grow or are not damped excessively, so that the waves can exist and might thus lead to the observed differential speeds. However, the way in which the alpha particles exceed the proton velocity remains unexplained.
Particle-two particle interaction in configuration space
International Nuclear Information System (INIS)
Kuzmichev, V.E.
1982-07-01
The problem if three indentical particles with zero-range two-particle interaction is considered. An explicit expression for the effective potential between one particle and the remaining two-particle system is obtained in the coordinate representation. It is shown that for arbitrary energies, at small and, for zero energy, at large distances rho between the one particle and centre of mass of the other two particles the diagonal matrix element of the effective potential is attractive and proportional to 1/rho 2 . This property of the effective potenial explains both the Thomas singularity and the Efimov effect. In the case of zero total energy of the system the general form of the solution of the three-particle integral equation is found in configuration space. (orig.)
Wave-current interaction in Willapa Bay
Olabarrieta, Maitane; Warner, John C.; Kumar, Nirnimesh
2011-01-01
This paper describes the importance of wave-current interaction in an inlet-estuary system. The three-dimensional, fully coupled, Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system was applied in Willapa Bay (Washington State) from 22 to 29 October 1998 that included a large storm event. To represent the interaction between waves and currents, the vortex-force method was used. Model results were compared with water elevations, currents, and wave measurements obtained by the U.S. Army Corp of Engineers. In general, a good agreement between field data and computed results was achieved, although some discrepancies were also observed in regard to wave peak directions in the most upstream station. Several numerical experiments that considered different forcing terms were run in order to identify the effects of each wind, tide, and wave-current interaction process. Comparison of the horizontal momentum balances results identified that wave-breaking-induced acceleration is one of the leading terms in the inlet area. The enhancement of the apparent bed roughness caused by waves also affected the values and distribution of the bottom shear stress. The pressure gradient showed significant changes with respect to the pure tidal case. During storm conditions the momentum balance in the inlet shares the characteristics of tidal-dominated and wave-dominated surf zone environments. The changes in the momentum balance caused by waves were manifested both in water level and current variations. The most relevant effect on hydrodynamics was a wave-induced setup in the inner part of the estuary.
Narrow Escape of Interacting Diffusing Particles
Agranov, Tal; Meerson, Baruch
2018-03-01
The narrow escape problem deals with the calculation of the mean escape time (MET) of a Brownian particle from a bounded domain through a small hole on the domain's boundary. Here we develop a formalism which allows us to evaluate the nonescape probability of a gas of diffusing particles that may interact with each other. In some cases the nonescape probability allows us to evaluate the MET of the first particle. The formalism is based on the fluctuating hydrodynamics and the recently developed macroscopic fluctuation theory. We also uncover an unexpected connection between the narrow escape of interacting particles and thermal runaway in chemical reactors.
International Nuclear Information System (INIS)
Vainer, B.V.; Nasel'skii, P.D.
1983-01-01
Equations for the correlation functions of fluctuations in the spectra of relativistic collisionless particles are obtained from the combined system of Einstein's equations and the Vlasov equation. It is shown that the interaction of high-frequency gravitational waves with collisionless particles leads to diffusion of their spectrum in the momentum space. The distortions in the spectrum of the microwave background radiation in a cosmological model with high-frequency gravitational waves are discussed. Bounds are obtained on the spectral characteristics of background gravitational waves
Wave-particle energy exchange directly observed in a kinetic Alfvén-branch wave.
Gershman, Daniel J; F-Viñas, Adolfo; Dorelli, John C; Boardsen, Scott A; Avanov, Levon A; Bellan, Paul M; Schwartz, Steven J; Lavraud, Benoit; Coffey, Victoria N; Chandler, Michael O; Saito, Yoshifumi; Paterson, William R; Fuselier, Stephen A; Ergun, Robert E; Strangeway, Robert J; Russell, Christopher T; Giles, Barbara L; Pollock, Craig J; Torbert, Roy B; Burch, James L
2017-03-31
Alfvén waves are fundamental plasma wave modes that permeate the universe. At small kinetic scales, they provide a critical mechanism for the transfer of energy between electromagnetic fields and charged particles. These waves are important not only in planetary magnetospheres, heliospheres and astrophysical systems but also in laboratory plasma experiments and fusion reactors. Through measurement of charged particles and electromagnetic fields with NASA's Magnetospheric Multiscale (MMS) mission, we utilize Earth's magnetosphere as a plasma physics laboratory. Here we confirm the conservative energy exchange between the electromagnetic field fluctuations and the charged particles that comprise an undamped kinetic Alfvén wave. Electrons confined between adjacent wave peaks may have contributed to saturation of damping effects via nonlinear particle trapping. The investigation of these detailed wave dynamics has been unexplored territory in experimental plasma physics and is only recently enabled by high-resolution MMS observations.
Wave-Particle Energy Exchange Directly Observed in a Kinetic Alfven-Branch Wave
Gershman, Daniel J.; F-Vinas, Adolfo; Dorelli, John C.; Boardsen, Scott A. (Inventor); Avanov, Levon A.; Bellan, Paul M.; Schwartz, Steven J.; Lavraud, Benoit; Coffey, Victoria N.; Chandler, Michael O.;
2017-01-01
Alfven waves are fundamental plasma wave modes that permeate the universe. At small kinetic scales they provide a critical mechanism for the transfer of energy between electromagnetic fields and charged particles. These waves are important not only in planetary magnetospheres, heliospheres, and astrophysical systems, but also in laboratory plasma experiments and fusion reactors. Through measurement of charged particles and electromagnetic fields with NASAs Magnetospheric Multiscale (MMS) mission, we utilize Earths magnetosphere as a plasma physics laboratory. Here we confirm the conservative energy exchange between the electromagnetic field fluctuations and the charged particles that comprise an undamped kinetic Alfven wave. Electrons confined between adjacent wave peaks may have contributed to saturation of damping effects via non-linear particle trapping. The investigation of these detailed wave dynamics has been unexplored territory in experimental plasma physics and is only recently enabled by high-resolution MMS observations.
Long-range particle manipulation in a micro-capillary tube by using a flexural acoustic wave
International Nuclear Information System (INIS)
Kim, Eun-Sun; Kim, Nari; Kim, Young-Ho; Lee, Kwang-Jo; Hwang, In-Kag
2010-01-01
We report a one-dimensional manipulation of dry Ag particles in micro-capillary tube by using a flexural acoustic wave propagating along the tube. The capillary tube is used as a mechanical guide for both the particles and the acoustic wave, resulting in an effective interaction between them over a long range of 14 cm in length. Linear transport and local trapping of the particles are demonstrated by the excitation of traveling and standing acoustic waves, respectively. The mechanisms for the particle movements are qualitatively explained by frictional forces between the particles and the inner wall of the capillary tube.
Consecutive opposed interactions of light waves
International Nuclear Information System (INIS)
Volkov, V V; Chirkin, Anatolii S
1999-01-01
The conditions were determined for the occurrence of the opposed interaction of waves having multiple frequencies in two consecutive three-frequency processes in periodically inhomogeneous nonlinear optical crystals. The necessary nonlinear susceptibility modulation period was calculated for an MgO:LiNbO 3 crystal. The characteristic features of the energy exchange between counterpropagating waves with parametric amplification in a low-frequency pump field were investigated. (nonlinear optical phenomena)
WAVE: Interactive Wave-based Sound Propagation for Virtual Environments.
Mehra, Ravish; Rungta, Atul; Golas, Abhinav; Ming Lin; Manocha, Dinesh
2015-04-01
We present an interactive wave-based sound propagation system that generates accurate, realistic sound in virtual environments for dynamic (moving) sources and listeners. We propose a novel algorithm to accurately solve the wave equation for dynamic sources and listeners using a combination of precomputation techniques and GPU-based runtime evaluation. Our system can handle large environments typically used in VR applications, compute spatial sound corresponding to listener's motion (including head tracking) and handle both omnidirectional and directional sources, all at interactive rates. As compared to prior wave-based techniques applied to large scenes with moving sources, we observe significant improvement in runtime memory. The overall sound-propagation and rendering system has been integrated with the Half-Life 2 game engine, Oculus-Rift head-mounted display, and the Xbox game controller to enable users to experience high-quality acoustic effects (e.g., amplification, diffraction low-passing, high-order scattering) and spatial audio, based on their interactions in the VR application. We provide the results of preliminary user evaluations, conducted to study the impact of wave-based acoustic effects and spatial audio on users' navigation performance in virtual environments.
Scattering of spinning test particles by gravitational plane waves
International Nuclear Information System (INIS)
Bini, D.; Gemelli, G.
1997-01-01
The authors study the motion of spinning particles in the gravitational plane-wave background and discuss particular solutions under a suitable choice of supplementary conditions. An analysis of the discontinuity of the motion across the wavefront is presented too
Test particle modeling of wave-induced energetic electron precipitation
International Nuclear Information System (INIS)
Chang, H.C.; Inan, U.S.
1985-01-01
A test particle computer model of the precipitation of radiation belt electrons is extended to compute the dynamic energy spectrum of transient electron fluxes induced by short-duration VLF wave packets traveling along the geomagnetic field lines. The model is adapted to estimate the count rate and associated spectrum of precipitated electrons that would be observed by satellite-based particle detectors with given geometric factor and orientation with respect to the magnetic field. A constant-frequency wave pulse and a lightning-induced whistler wave packet are used as examples of the stimulating wave signals. The effects of asymmetry of particle mirror heights in the two hemispheres and the atmospheric backscatter of loss cone particles on the computed precipitated fluxes are discussed
Hydrodynamic limit of interacting particle systems
International Nuclear Information System (INIS)
Landim, C.
2004-01-01
We present in these notes two methods to derive the hydrodynamic equation of conservative interacting particle systems. The intention is to present the main ideas in the simplest possible context and refer for details and references. (author)
Anomalous transport of magnetized electrons interacting with EC waves
Energy Technology Data Exchange (ETDEWEB)
Tsironis, C; Vlahos, L [Section of Astrophysics, Astronomy and Mechanics, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)
2005-01-01
We consider the nonlinear interaction of magnetized electrons with an oblique narrow-band electromagnetic wave-packet. The interaction is analysed over and near the local threshold to chaos. The statistical character of the forcing that controls the trajectories of the particles is also studied. We focus our analysis on issues related to energy and spatial diffusion across the magnetic field by following the evolution of the ensemble mean squares (({gamma} - {gamma}{sub 0}){sup 2}) and ((r{sub perpendicular}-r{sub perpendicular0}){sup 2}) for various values of the wave amplitude and angle of wave propagation. We study, in particular, the interaction of magnetized electrons with waves having strong and moderate amplitudes, near the transition to chaos, where the dynamics is complex and a mixture of periodic and stochastic orbits coexist. The electron diffusions in real and energy spaces are found to obey simple power laws in time, and the scaling exponents are indicative of sub-diffusion. This is a direct consequence of the effect of the resonant phase-space islands in the particle motion.
Interaction dynamics of electrostatic solitary waves
Directory of Open Access Journals (Sweden)
V. L. Krasovsky
1999-01-01
Full Text Available Interaction of nonlinear electrostatic pulses associated with electron phase density holes moving in a collisionless plasma is studied. An elementary event of the interaction is analyzed on the basis of the energy balance in the system consisting of two electrostatic solitary waves. It is established that an intrinsic property of the system is a specific irreversibility caused by a nonadiabatic modification of the internal structure of the holes and their effective heating in the process of the interaction. This dynamical irreversibility is closely connected with phase mixing of the trapped electrons comprising the holes and oscillating in the varying self-consistent potential wells. As a consequence of the irreversibility, the "collisions" of the solitary waves should be treated as "inelastic" ones. This explains the general tendency to the merging of the phase density holes frequently observed in numerical simulation and to corresponding coupling of the solitary waves.
Workshop on wave-ice interaction
Wadhams, Peter; Squire, Vernon; Rottier, Philip; Liu, Antony; Dugan, John; Czipott, Peter; Shen, Hayley
The subject of wave-ice interaction has been advanced in recent years by small groups of researchers working on a similar range of topics in widely separated geographic locations. Their recent studies inspired a workshop on wave-ice interaction held at the Scott Polar Research Institute, University of Cambridge, England, December 16-18, 1991, where theories in all aspects of the physics of wave-ice interaction were compared.Conveners of the workshop hoped that plans for future observational and theoretical work dealing with outstanding issues in a collaborative way would emerge. The workshop, organized by the Commission on Sea Ice of the International Association for Physical Sciences of the Ocean (IAPSO), was co-chaired by Vernon Squire, professor of mathematics and statistics at the University of Otago, New Zealand, and Peter Wadhams, director of the Scott Polar Research Institute. Participants attended from Britain, Finland, New Zealand, Norway, and the United States.
Vector potential quantization and the photon wave-particle representation
International Nuclear Information System (INIS)
Meis, C; Dahoo, P R
2016-01-01
The quantization procedure of the vector potential is enhanced at a single photon state revealing the possibility for a simultaneous representation of the wave-particle nature of the photon. Its relationship to the quantum vacuum results naturally. A vector potential amplitude operator is defined showing the parallelism with the Hamiltonian of a massless particle. It is further shown that the quantized vector potential satisfies both the wave propagation equation and a linear time-dependent Schrödinger-like equation. (paper)
Higgs particles interacting via a scalar Dark Matter field
Directory of Open Access Journals (Sweden)
Bhattacharya Yajnavalkya
2016-01-01
Full Text Available We study a system of two Higgs particles, interacting via a scalar Dark Matter mediating field. The variational method in the Hamiltonian formalism of QFT is used to derive relativistic wave equations for the two-Higgs system, using a truncated Fock-space trial state. Approximate solutions of the two-body equations are used to examine the existence of Higgs bound states.
Particle nature of light waves in dielectric media
International Nuclear Information System (INIS)
Tan, C.Z.
2009-01-01
Wave-particle duality is a foundation for modern science. The speed of light waves in dielectric media is less than c. The corresponding particles thus have mass. Combining wave-particle duality with the theory of relativity, an exactly solvable problem was proposed, concerning the transition from photons in vacuum to particles in dielectric media. The rest mass, the momentum, and the total energy of material particles are shown to be the functions of the refractive index of the medium and the wavelength of the incident light. The proposed relationships were applied to study the wavelength-dependent index of refraction of dielectrics and the correlation of the refractive indices of anisotropic crystals, which were confirmed by the experimental results. Variation of the refractive index with wavelength is found to obey the proposed relation. The refractive indices of anisotropic crystals are shown to be the correlated quantities.
Nonlinear instability and chaos in plasma wave-wave interactions
International Nuclear Information System (INIS)
Kueny, C.S.
1993-01-01
Conventional linear stability analysis may fail for fluid systems with an indefinite free energy functional. When such a system is linearly stable, it is said to possess negative energy modes. Instability may then occur either via dissipation of the negative energy modes. Instability may then occur either via dissipation of the negative energy modes. Instability may then occur either via dissipitation of the negative energy modes, or nonlinearly via resonant wave-wave coupling, which leads to explosive growth. In the dissipationaless case, it is conjectured that intrinsic chaotic behavior may allow initially non-resonant systems to reach resonance by diffusion in phase space. This is illustrated for a simple equilibrium involving cold counter-streaming ions. The system is described in the fluid approximation by a Hamilitonian functional and associated noncanonical Poisson bracket. By Fourier decomposition and appropriate coordinate transformations, the Hamilitonian for the perturbed energy is expressed in action-angle form. The normal modes correspond to Doppler-shifted ion-acoustic waves of positive and negative energy. Nonlinear coupling leads to decay instability via two-wave interactions, which occur generically for long enough wavelengths. Three-wave interactions which occur in isolated, but numerous, regions of parameter space can drive either decay instability or explosive instability. When the resonance for explosive growth is detuned, a stable region exists around the equilibrium point in phase space, while explosive growth occurs outside of a separatrix. These interactions may be described exactly if only one resonance is considered, while multiple nonlinear terms make the Hamiltonian nonintegradable. Simple Hamiltonians of two and three degrees of freedom are studied numerically using symplectic integration algorithms, including an explicit algorithm derived using Lie algebraic methods
Particle interactions in concentrated suspensions
International Nuclear Information System (INIS)
Mondy, L.A.; Graham, A.L.; Abbott, J.R.; Brenner, H.
1993-01-01
An overview is presented of research that focuses on slow flows of suspensions in which colloidal and inertial effects are negligibly small. The authors describe nuclear magnetic resonance imaging experiments to quantitatively measure particle migration occurring in concentrated suspensions undergoing a flow with a nonuniform shear rate. These experiments address the issue of how the flow field affects the microstructure of suspensions. In order to understand the local viscosity in a suspension with such a flow-induced, spatially varying concentration, one must know how the viscosity of a homogeneous suspension depends on such variables as solids concentration and particle orientation. The authors suggest the technique of falling ball viscometry, using small balls, as a method to determine the effective viscosity of a suspension without affecting the original microstructure significantly. They also describe data from experiments in which the detailed fluctuations of a falling ball's velocity indicate the noncontinuum nature of the suspension and may lead to more insights into the effects of suspension microstructure on macroscopic properties. Finally, they briefly describe other experiments that can be performed in quiescent suspensions (in contrast to the use of conventional shear rotational viscometers) in order to learn more about boundary effects in concentrated suspensions
Waves and particles two essays on fundamental physics
Newton, Roger G
2014-01-01
The book consists of two separate parts, the first part is on waves and the second part on particles. In part 1, after describing the awesome power of tsunami and the history of their occurrences, the book turns to the history of explaining phenomena by means of mathematical equations. Then it describes other wave phenomena and the laws governing them: the vibration of strings and drums in musical instruments, the sound waves making them audible, ultrasound and its uses, sonar, and shock waves; electromagnetic waves: light waves, refraction, diffraction, why the sky is blue, the rainbow, and the glory; microwaves and radio waves: radar, radio astronomy, the discovery of the cosmic microwave background radiation, microwave ovens and how a radio works, lasers and masers; waves in modern physics: the Schrödinger wave function and gravitational waves in general relativity; water waves in the ocean, tides and tidal waves, and the quite different solitary waves, solitons discovered in canals. Finally we return to ...
The Particle Beam Optics Interactive Computer Laboratory
International Nuclear Information System (INIS)
Gillespie, G.H.; Hill, B.W.; Brown, N.A.; Babcock, R.C.; Martono, H.; Carey, D.C.
1997-01-01
The Particle Beam Optics Interactive Computer Laboratory (PBO Lab) is an educational software concept to aid students and professionals in learning about charged particle beams and particle beam optical systems. The PBO Lab is being developed as a cross-platform application and includes four key elements. The first is a graphic user interface shell that provides for a highly interactive learning session. The second is a knowledge database containing information on electric and magnetic optics transport elements. The knowledge database provides interactive tutorials on the fundamental physics of charged particle optics and on the technology used in particle optics hardware. The third element is a graphical construction kit that provides tools for students to interactively and visually construct optical beamlines. The final element is a set of charged particle optics computational engines that compute trajectories, transport beam envelopes, fit parameters to optical constraints and carry out similar calculations for the student designed beamlines. The primary computational engine is provided by the third-order TRANSPORT code. Augmenting TRANSPORT is the multiple ray tracing program TURTLE and a first-order matrix program that includes a space charge model and support for calculating single particle trajectories in the presence of the beam space charge. This paper describes progress on the development of the PBO Lab. copyright 1997 American Institute of Physics
The Particle Beam Optics Interactive Computer Laboratory
International Nuclear Information System (INIS)
Gillespie, George H.; Hill, Barrey W.; Brown, Nathan A.; Babcock, R. Chris; Martono, Hendy; Carey, David C.
1997-01-01
The Particle Beam Optics Interactive Computer Laboratory (PBO Lab) is an educational software concept to aid students and professionals in learning about charged particle beams and particle beam optical systems. The PBO Lab is being developed as a cross-platform application and includes four key elements. The first is a graphic user interface shell that provides for a highly interactive learning session. The second is a knowledge database containing information on electric and magnetic optics transport elements. The knowledge database provides interactive tutorials on the fundamental physics of charged particle optics and on the technology used in particle optics hardware. The third element is a graphical construction kit that provides tools for students to interactively and visually construct optical beamlines. The final element is a set of charged particle optics computational engines that compute trajectories, transport beam envelopes, fit parameters to optical constraints and carry out similar calculations for the student designed beamlines. The primary computational engine is provided by the third-order TRANSPORT code. Augmenting TRANSPORT is the multiple ray tracing program TURTLE and a first-order matrix program that includes a space charge model and support for calculating single particle trajectories in the presence of the beam space charge. This paper describes progress on the development of the PBO Lab
Quantum symmetries in particle interactions
International Nuclear Information System (INIS)
Shirkov, D.V.
1983-01-01
The concept of a quantum symmetry is introduced as a symmetry in the formulation of which quantum representations and specific quantum notions are used essentially. Three quantum symmetry principles are discussed: the principle of renormalizability (possibly super-renormalizability), the principle of local gauge symmetry, and the principle of supersymmetry. It is shown that these principles play a deterministic role in the development of quantum field theory. Historically their use has led to ever stronger restrictions on the interaction mechanism of quantum fields
Numerical modelling of extreme waves by Smoothed Particle Hydrodynamics
Directory of Open Access Journals (Sweden)
M. H. Dao
2011-02-01
Full Text Available The impact of extreme/rogue waves can lead to serious damage of vessels as well as marine and coastal structures. Such extreme waves in deep water are characterized by steep wave fronts and an energetic wave crest. The process of wave breaking is highly complex and, apart from the general knowledge that impact loadings are highly impulsive, the dynamics of the breaking and impact are still poorly understood. Using an advanced numerical method, the Smoothed Particle Hydrodynamics enhanced with parallel computing is able to reproduce well the extreme waves and their breaking process. Once the waves and their breaking process are modelled successfully, the dynamics of the breaking and the characteristics of their impact on offshore structures could be studied. The computational methodology and numerical results are presented in this paper.
Experimental investigation of shock wave - bubble interaction
Energy Technology Data Exchange (ETDEWEB)
Alizadeh, Mohsen
2010-04-09
In this work, the dynamics of laser-generated single cavitation bubbles exposed to lithotripter shock waves has been investigated experimentally. The energy of the impinging shock wave is varied in several steps. High-speed photography and pressure field measurements simultaneously with image acquisition provide the possibility of capturing the fast bubble dynamics under the effect of the shock wave impact. The pressure measurement is performed using a fiber optic probe hydrophone (FOPH) which operates based on optical diagnostics of the shock wave propagating medium. After a short introduction in chapter 1 an overview of the previous studies in chapter 2 is presented. The reported literatures include theoretical and experimental investigations of several configurations of physical problems in the field of bubble dynamics. In chapter 3 a theoretical description of propagation of a shock wave in a liquid like water has been discussed. Different kinds of reflection of a shock wave at an interface are taken into account. Undisturbed bubble dynamics as well as interaction between a planar shock wave and an initially spherical bubble are explored theoretically. Some physical parameters which are important in this issue such as the velocity of the shock-induced liquid jet, Kelvin impulse and kinetic energy are explained. The shock waves are generated in a water filled container by a focusing piezoelectric generator. The shock wave profile has a positive part with pulse duration of ∼1 μs followed by a longer tension tail (i.e. ∼3 μs). In chapter 4 high-speed images depict the propagation of a shock wave in the water filled tank. The maximum pressure is also derived for different intensity levels of the shock wave generator. The measurement is performed in the free field (i.e. in the absence of laser-generated single bubbles). In chapter 5 the interaction between lithotripter shock waves and laserinduced single cavitation bubbles is investigated experimentally. An
Elementary particles and physics interaction unification
International Nuclear Information System (INIS)
Leite-Lopes, J.
1985-01-01
Quantum theory and relativity theory are fundamental of relativistic quantum mechanics, quantum field theory, which is the base of elementary particle physics, gauge field theory and basic force unification models. After a short introduction of relativistic equations of the main fields, the free scalar field, the free vector field, the free electromagnetic field and the free spinor field, and of elementary particles and basic interactions, gauge invariance and electromagnetic gauge field are detailed. Then the presentation of internal degrees of freedom, especially isospin, introduces gauge field theory of Yang-Mills. At last weak interactions and strong interactions are presented and lead to grand unification theory in conclusion [fr
International Nuclear Information System (INIS)
Bellan, P. M.
2013-01-01
The interaction between a circularly polarized wave and an energetic gyrating particle is described using a relativistic pseudo-potential that is a function of the frequency mismatch. Analysis of the pseudo-potential provides a means for interpreting numerical results. The pseudo-potential profile depends on the initial mismatch, the normalized wave amplitude, and the initial angle between the wave magnetic field and the particle perpendicular velocity. For zero initial mismatch, the pseudo-potential consists of only one valley, but for finite mismatch, there can be two valleys separated by a hill. A large pitch angle scattering of the energetic electron can occur in the two-valley situation but fast scattering can also occur in a single valley. Examples relevant to magnetospheric whistler waves show that the energetic electron pitch angle can be deflected 5°towards the loss cone when transiting a 10 ms long coherent wave packet having realistic parameters.
Mathieu functions describing particles evolving in electromagnetic waves
Mihu, Denisa-Andreea; Dariescu, Marina-Aura
2017-12-01
Solutions of Klein-Gordon equation for particles moving in a standing wave configuration bring into attention an intricate and complicated category of special functions, namely the Mathieu functions. The stability of the solutions governed by the intercorrelation between Mathieu equation' parameters is discussed. For specific intervals of the wave number, the instability regime installs, pointing out the tendency of exponential growth for the oscillatory wave functions, as a consequence of parametric resonance phenomenon. The expression of the wave function allows the computation of the four-dimensional conserved current density components.
Path integral for spinning particle in the plane wave field: Global and local projections
International Nuclear Information System (INIS)
Boudiaf, N.; Boudjedaa, T.; Chetouani, L.
2001-01-01
The Green function related to the problem of a Dirac particle interacting with a plane wave is calculated via the path integral formalism proposed recently by Alexandrou et al. according to the two so-called global and local projections. With the help of the incorporation of two simple identities, it is shown that the contribution to the calculation of the integrals comes essentially from classical solutions projected along the direction of wave propagation. (orig.)
De Broglie's Wavefunction and Wave-Particle Dualism
International Nuclear Information System (INIS)
Leydolt, Hans J.
2005-01-01
A different approach to wave mechanics is presented in accordance with de Broglie's original hypothesis applying the case of photons to all material particles. It derives propagating matter waves conceptually from a theory of evolution, and not by the formal setting of eigenvalue equations. The quality of explanation is at issue, and not the mere description of phenomena. A monoenergetic particle transport along two directions is described by a partial differential equation and by a random walk model. The dual description is applied to the particle picture and the wave picture; it leads with identical initial values to identical causal and timelike solutions in either picture. The partial differential equations are a Telegrapher equation in 1-d space and its analytic continuation, a modified Klein Gordon equation; the solutions represent a density distribution and an amplitude profile, respectively. However, only the corresponding random walk models - equivalent to Feynman's integral over all paths - derive the solutions as path-end distributions with the additional information about the flight direction. This allows following up momentum dissipation along two directions by means of two particle beams and their profiles. Thereby the total number of particles is divided up onto the two beams according to linear or squared fractions depending on the beam configuration putting up a 1-d or a 2-d space. This aspect escapes conventional descriptions but serves to describe the transport in the particle or in the wave picture in dependence on the knowledge/ignorance of the particle's flight direction
Shock wave interactions with detonable clouds
International Nuclear Information System (INIS)
Ripley, R.C.; Josey, T.; Donahue, L.; Whitehouse, D.R.
2004-01-01
This paper presents results from the numerical simulation of compressible multi-species gases in an unstructured mesh CFD code called Chinook. Multiple species gases are significant to a wide range of CFD applications that involve chemical reactions, in particular detonation. The purpose of this paper is to investigate the interaction of shock waves with localized regions of reactive and non-reactive gas species. Test cases are chosen to highlight shock reflection and acceleration through combustion products resulting from the detonation of an explosive charge, and detonation wave propagation through a fuel-air cloud. Computations are performed in a 2D axi-symmetric framework. (author)
International Nuclear Information System (INIS)
Vladimirov, S.V.; Nambu, Mitsuhiro
1995-01-01
From investigations of resonant interactions of particles and waves in turbulent plasmas it is well known that not only resonant particles contribute to expressions for the wave energy and momentum providing conservation of these quantities for closed systems. In particular, it was demonstrated that contribution of the nonresonant particles is very important for the energy conservation in the quasilinear theory: although the nonresonant terms do not appear in the diffusion equation, they contribute to the wave energy (and, in general, wave momentum) ensuring the conservation of total energy (and momentum) in the system. We note that the real part of the dielectric permittivity ε ωk as well as the wave frequency ω k of the resonant waves do not depend on time in the quasilinear approximation since only nonresonant particles (which distribution is constant) contribute to them. The resonant wave amplitude, however, is the function on time, and changing of the wave energy is completely balanced by the corresponding change of the resonant particle energy. If in the system there are only nonresonant waves, and it is closed (i.e., there is no energy exchange with some external sources or sinks), the system is stationary and the nonresonant wave as well as particle energy are not changing
Weakly interacting massive particles and stellar structure
International Nuclear Information System (INIS)
Bouquet, A.
1988-01-01
The existence of weakly interacting massive particles (WIMPs) may solve both the dark matter problem and the solar neutrino problem. Such particles affect the energy transport in the stellar cores and change the stellar structure. We present the results of an analytic approximation to compute these effects in a self-consistent way. These results can be applied to many different stars, but we focus on the decrease of the 8 B neutrino flux in the case of the Sun
Interactive methods for exploring particle simulation data
Energy Technology Data Exchange (ETDEWEB)
Co, Christopher S.; Friedman, Alex; Grote, David P.; Vay, Jean-Luc; Bethel, E. Wes; Joy, Kenneth I.
2004-05-01
In this work, we visualize high-dimensional particle simulation data using a suite of scatter plot-based visualizations coupled with interactive selection tools. We use traditional 2D and 3D projection scatter plots as well as a novel oriented disk rendering style to convey various information about the data. Interactive selection tools allow physicists to manually classify ''interesting'' sets of particles that are highlighted across multiple, linked views of the data. The power of our application is the ability to correspond new visual representations of the simulation data with traditional, well understood visualizations. This approach supports the interactive exploration of the high-dimensional space while promoting discovery of new particle behavior.
Trapped electron losses by interactions with coherent VLF waves
International Nuclear Information System (INIS)
Walt, M.; Inan, U.S.; Voss, H.D.
1996-01-01
VLF whistler waves from lightning enter the magnetosphere and cause the precipitation of energetic trapped electrons by pitch angle scattering. These events, known as Lightning-induced Electron Precipitation (LEP) have been detected by satellite and rocket instruments and by perturbations of VLF waves traveling in the earth-ionosphere waveguide. Detailed comparison of precipitating electron energy spectra and time dependence are in general agreement with calculations of trapped electron interactions with ducted whistler waves. In particular the temporal structure of the precipitation and the dynamic energy spectra of the electrons confirm this interpretation of the phenomena. There are discrepancies between observed and measured electron flux intensities and pitch angle distributions, but these quantities are sensitive to unknown wave intensities and trapped particle fluxes near the loss cone angle. The overall effect of lightning generated VLF waves on the lifetime of trapped electrons is still uncertain. The flux of electrons deflected into the bounce loss cone by a discrete whistler wave has been measured in a few cases. However, the area of the precipitation region is not known, and thus the total number of electrons lost in an LEP event can only be estimated. While the LEP events are dramatic, more important effects on trapped electrons may arise from the small but numerous deflections which increase the pitch angle diffusion rate of the electron population. copyright 1996 American Institute of Physics
Trapped electron losses by interactions with coherent VLF waves
Walt, M.; Inan, U. S.; Voss, H. D.
1996-07-01
VLF whistler waves from lightning enter the magnetosphere and cause the precipitation of energetic trapped electrons by pitch angle scattering. These events, known as Lightning-induced Electron Precipitation (LEP) have been detected by satellite and rocket instruments and by perturbations of VLF waves traveling in the earth-ionosphere waveguide. Detailed comparison of precipitating electron energy spectra and time dependence are in general agreement with calculations of trapped electron interactions with ducted whistler waves. In particular the temporal structure of the precipitation and the dynamic energy spectra of the electrons confirm this interpretation of the phenomena. There are discrepancies between observed and measured electron flux intensities and pitch angle distributions, but these quantities are sensitive to unknown wave intensities and trapped particle fluxes near the loss cone angle. The overall effect of lightning generated VLF waves on the lifetime of trapped electrons is still uncertain. The flux of electrons deflected into the bounce loss cone by a discrete whistler wave has been measured in a few cases. However, the area of the precipitation region is not known, and thus the total number of electrons lost in an LEP event can only be estimated. While the LEP events are dramatic, more important effects on trapped electrons may arise from the small but numerous deflections which increase the pitch angle diffusion rate of the electron population.
Double layers, waves and particle acceleration
Energy Technology Data Exchange (ETDEWEB)
Bryant, D.A.; Perry, C.H.; Bingham, R.; de Angelis, U.
1993-09-01
The author's conclusions that static potential differences, including those associated with double layers, could not be the cause of auroral electron acceleration, and that resonance with electrostatic wave turbulence provided a possible mechanism were dismissed in a recent publication as being totally incorrect. In this reply, the author finds the criticism to be built upon a number of misconceptions and factual errors which render it invalid. He is, therefore, able to re-affirm his earlier conclusions.
Fully resolved simulations of expansion waves propagating into particle beds
Marjanovic, Goran; Hackl, Jason; Annamalai, Subramanian; Jackson, Thomas; Balachandar, S.
2017-11-01
There is a tremendous amount of research that has been done on compression waves and shock waves moving over particles but very little concerning expansion waves. Using 3-D direct numerical simulations, this study will explore expansion waves propagating into fully resolved particle beds of varying volume fractions and geometric arrangements. The objectives of these simulations are as follows: 1) To fully resolve all (1-way coupled) forces on the particles in a time varying flow and 2) to verify state-of-the-art drag models for such complex flows. We will explore a range of volume fractions, from very low ones that are similar to single particle flows, to higher ones where nozzling effects are observed between neighboring particles. Further, we will explore two geometric arrangements: body centered cubic and face centered cubic. We will quantify the effects that volume fraction and geometric arrangement plays on the drag forces and flow fields experienced by the particles. These results will then be compared to theoretical predictions from a model based on the generalized Faxen's theorem. This work was supported in part by the U.S. Department of Energy under the Predictive Science Academic Alliance Program, under Contract No. DE-NA0002378.
[Research in elementary particles and interactions
International Nuclear Information System (INIS)
Adair, R.; Sandweiss, J.; Schmidt, M.
1992-05-01
Research of the Yale University groups in the areas of elementary particles and their interactions are outlined. Work on the following topics is reported: development of CDF trigger system; SSC detector development; study of heavy flavors at TPL; search for composite objects produced in relativistic heavy-ion collisions; high-energy polarized lepton-nucleon scattering; rare K + decays; unpolarized high-energy muon scattering; muon anomalous magnetic moment; theoretical high-energy physics including gauge theories, symmetry breaking, string theory, and gravitation theory; study of e + e - interactions with the SLD detector at SLAC; and the production and decay of particles containing charm and beauty quarks
Solitary Wave Interactions in Granular Media
Institute of Scientific and Technical Information of China (English)
WEN Zhen-Ying; WANG Shun-Jin; ZHANG Xiu-Ming; LI Lei
2007-01-01
We numerically study the interactions of solitary waves in granular media, by considering a chain of beads, which repel upon contact via the Hertz-type potential, V ∝δn, with 5/2 ≤n≤3 and δ≥0,δbeing the bead-bead overlap. There are two collision types of solitary waves, overtaking collision and head-on collision, in the chain of beads. Our quantitative results show that after collision the large solitary wave gains energy and the small one loses energy for overtaking type while the large one loses energy, and the small one gains energy for head-on type. The scattering effects decrease with n for overtaking collision whereas increase with n for head-on collision.
International Nuclear Information System (INIS)
Erokhin, N.S.; Zol'nikova, N.N.; Kuznetsov, E.A.; Mikhajlovskaya, L.A.
2010-01-01
Based on numerical calculations considered the relativistic acceleration of charged particles in space plasma when surfing on the spatially localized package of electromagnetic waves. The problem is reduced to the study of unsteady, nonlinear equation for the wave phase at the carrier frequency at the location of the accelerated charge, which is solved numerically. We study the temporal dynamics of the relativistic factor, the component of momentum and velocity of the particle, its trajectory is given gyro-rotation in an external magnetic field after the departure of the effective potential well. Dependence of the dynamics of a particle interacting with the wave of the sign of the velocity of the charge along the wave front. We formulate the optimal conditions of the relativistic particle acceleration wave packet, indicate the possibility of again (after a number gyro-turnover) charge trapping wave with an additional relativistic acceleration.
Relativistic mechanics of two interacting particles and bilocal theory
International Nuclear Information System (INIS)
Takabayasi, Takehiko
1975-01-01
New relativistic mechanics of two-particle system is set forth, where the two constituent particles are interacting by an arbitrary (central) action-at-a-distance. The fundamental equations are presented in a form covariant under general transformation of parameters parametrizing the world lines of constituent particles. The theory represents the proper relativistic generalization of the usual Newtonian mechanics in the sense that it tends in the non-relativistic (and weak interaction) limit to the usual mechanics of two particles moving under a corresponding non-relativistic potential. For the analysis of theory it is convenient to choose a certain particular gauge (i.e., parametrization) fixed by two gauge relations. This brings the theory to a canonical formalism accompanied by two weak equations, and in this gauge quantization can be performed. The result verifies that the relativistic quantum mechanics for two particles interacting by an action-at-a-distance is just represented by a bilocal wave equation and a subsidiary condition, with the clarification of its correspondence-theoretical foundation and internal dynamics. As an example the case of Hooke-type force is illustrated, where the internal motions are elliptic oscillations in the center-of-mass frame. Its quantum theory just reproduces the original form of bilocal theory giving bound states lying on a straightly rising trajectory and on its daughter trajectories. (auth.)
Quasi-linear absorption of lower hybrid waves by fusion generated alpha particles
International Nuclear Information System (INIS)
Barbato, E.; Santini, F.
1991-01-01
Lower hybrid waves are expected to be used in a steady state reactor to produce current and to control the current profile and the stability of internal modes. In the ignition phase, however, the presence of energetic alpha particles may prevent wave-electron interaction, thus reducing the current drive efficiency. This is due to the very high birth energy of the alpha particles that may absorb much of the lower hybrid wave power. This unfavourable effect is absent at high frequencies (∼ 8 GHz for typical reactor parameters). Nevertheless, because of the technical difficulties involved in using such high frequencies, it is very important to investigate whether power absorption by alpha particles would be negligible also at relatively low frequencies. Such a study has been carried out on the basis of the quasi-linear theory of wave-alpha particle interaction, since the distortion of the alpha distribution function may enhance the radiofrequency absorption above the linear level. New effects have been found, such as local alpha concentration and acceleration. The model for alpha particles is coupled with a 1-D deposition code for lower hybrid waves to calculate the competition in the power absorption between alphas and electrons as the waves propagate into the plasma core for typical reactor (ITER) parameters. It is shown that at a frequency as low as 5 GHz, power absorption by alpha particles is negligible for conventional plasma conditions and realistic alpha particle concentrations. In more ''pessimistic'' and severe conditions, negligible absorption occurs at 6 GHz. (author). 19 refs, 11 figs, 2 tabs
Interaction and deformation of viscoelastic particles: Nonadhesive particles
International Nuclear Information System (INIS)
Attard, Phil
2001-01-01
A viscoelastic theory is formulated for the deformation of particles that interact with finite-ranged surface forces. The theory generalizes the static approach based upon classic continuum elasticity theory to account for time-dependent effects, and goes beyond contact theories such as Hertz and that given by Johnson, Kendall, and Roberts by including realistic surface interactions. Common devices used to measure load and deformation are modeled and the theory takes into account the driving velocity of the apparatus and the relaxation time of the material. Nonadhesive particles are modeled by an electric double layer repulsion. Triangular, step, and sinusoidal trajectories are analyzed in a unified treatment of loading and unloading. The load-deformation and the load-contact area curves are shown to be velocity dependent and hysteretic
Drift Wave Test Particle Transport in Reversed Shear Profile
International Nuclear Information System (INIS)
Horton, W.; Park, H.B.; Kwon, J.M.; Stronzzi, D.; Morrison, P.J.; Choi, D.I.
1998-01-01
Drift wave maps, area preserving maps that describe the motion of charged particles in drift waves, are derived. The maps allow the integration of particle orbits on the long time scale needed to describe transport. Calculations using the drift wave maps show that dramatic improvement in the particle confinement, in the presence of a given level and spectrum of E x B turbulence, can occur for q(r)-profiles with reversed shear. A similar reduction in the transport, i.e. one that is independent of the turbulence, is observed in the presence of an equilibrium radial electric field with shear. The transport reduction, caused by the combined effects of radial electric field shear and both monotonic and reversed shear magnetic q-profiles, is also investigated
Investigation on particle-solid interactions
International Nuclear Information System (INIS)
Yano, Syukuro
1988-08-01
Basic processes in plasma-material interactions have been surveyed and reviewed. Problems concerned with carbon materials, which have been progressively used for the first wall and limiters in Tokamaks, are mainly discussed. Recent usage of carbon materials, basic properties and characteristics of carbon/graphite materials, desorption of gasses are described. As to the interactions of incident hydrogen isotope particles with graphite surface, data of trapping, depth profile, reemission, isotope exchange, and diffusion are reviewed and discussed. (author)
Particle image velocimetry investigation of a finite amplitude pressure wave
Thornhill, D.; Currie, T.; Fleck, R.; Chatfield, G.
2006-03-01
Particle image velocimetry is used to study the motion of gas within a duct subject to the passage of a finite amplitude pressure wave. The wave is representative of the pressure waves found in the exhaust systems of internal combustion engines. Gas particles are accelerated from stationary to 150 m/s and then back to stationary in 8 ms. It is demonstrated that gas particles at the head of the wave travel at the same velocity across the duct cross section at a given point in time. Towards the tail of the wave viscous effects are plainly evident causing the flow profile to tend towards parabolic. However, the instantaneous mean particle velocity across the section is shown to match well with the velocity calculated from a corresponding measured pressure history using 1D gas dynamic theory. The measured pressure history at a point in the duct was acquired using a high speed pressure transducer of the type typically used for engine research in intake and exhaust systems. It is demonstrated that these are unable to follow the rapid changes in pressure accurately and that they are prone to resonate under certain circumstances.
"Strong interaction" for particle physics laboratories
2003-01-01
A new Web site pooling the communications resources of particle physics centres all over the world has just been launched. The official launching of the new particle physics website Interactions.org during the Lepton-Proton 2003 Conference at the American laboratory Fermilab was accompanied by music and a flurry of balloons. On the initiative of Fermilab, the site was created by a collaboration of communication teams from over fifteen of the world's particle physics laboratories, including KEK, SLAC, INFN, JINR and, of course, CERN, who pooled their efforts to develop the new tool. The spectacular launching of the new particle physics website Interactions.org at Fermilab on 12 August 2003. A real gateway to particle physics, the site not only contains all the latest news from the laboratories but also offers images, graphics and a video/animation link. In addition, it provides information about scientific policies, links to the universities, a very useful detailed glossary of particle physics and astrophysic...
A two-particle exchange interaction model
International Nuclear Information System (INIS)
Lyubina, Julia; Mueller, Karl-Hartmut; Wolf, Manfred; Hannemann, Ullrich
2010-01-01
The magnetisation reversal of two interacting particles was investigated within a simple model describing exchange coupling of magnetically uniaxial single-domain particles. Depending on the interaction strength W, the reversal may be cooperative or non-cooperative. A non-collinear reversal mode is obtained even for two particles with parallel easy axes. The model yields different phenomena as observed in spring magnets such as recoil hysteresis in the second quadrant of the field-magnetisation-plane, caused by exchange bias, as well as the mentioned reversal-rotation mode. The Wohlfarth's remanence analysis performed on aggregations of such pairs of interacting particles shows that the deviation δM(H m ) usually being considered as a hallmark of magnetic interaction vanishes for all maximum applied fields H m not only at W=0, but also for sufficiently large values of W. Furthermore, this so-called δM-plot depends on whether the sample is ac-field or thermally demagnetised.
A two-particle exchange interaction model
Energy Technology Data Exchange (ETDEWEB)
Lyubina, Julia, E-mail: j.lyubina@ifw-dresden.d [IFW Dresden, Institute for Metallic Materials, P.O. Box 270016, D-01171 Dresden (Germany); Mueller, Karl-Hartmut; Wolf, Manfred; Hannemann, Ullrich [IFW Dresden, Institute for Metallic Materials, P.O. Box 270016, D-01171 Dresden (Germany)
2010-10-15
The magnetisation reversal of two interacting particles was investigated within a simple model describing exchange coupling of magnetically uniaxial single-domain particles. Depending on the interaction strength W, the reversal may be cooperative or non-cooperative. A non-collinear reversal mode is obtained even for two particles with parallel easy axes. The model yields different phenomena as observed in spring magnets such as recoil hysteresis in the second quadrant of the field-magnetisation-plane, caused by exchange bias, as well as the mentioned reversal-rotation mode. The Wohlfarth's remanence analysis performed on aggregations of such pairs of interacting particles shows that the deviation {delta}M(H{sub m}) usually being considered as a hallmark of magnetic interaction vanishes for all maximum applied fields H{sub m} not only at W=0, but also for sufficiently large values of W. Furthermore, this so-called {delta}M-plot depends on whether the sample is ac-field or thermally demagnetised.
Atomic interactions of charged particles with matter
International Nuclear Information System (INIS)
Bichsel, H.
1993-01-01
Ideas about the interactions of charged particles with matter are discussed. First, some experimental information is presented. Concepts related to collision cross sections and the Bethe model for them are given. The stopping power is derived and applied to the discussion of depth dose functions ('Bragg curves'). Some details of the energy loss in microscopic volumes are discussed
Wave-induced mixing and transport of buoyant particles: application to the Statfjord A oil spill
Directory of Open Access Journals (Sweden)
M. Drivdal
2014-12-01
Full Text Available This study focuses on how wave–current and wave–turbulence interactions modify the transport of buoyant particles in the ocean. Here the particles can represent oil droplets, plastic particles, or plankton such as fish eggs and larvae. Using the General Ocean Turbulence Model (GOTM, modified to take surface wave effects into account, we investigate how the increased mixing by wave breaking and Stokes shear production, as well as the stronger veering by the Coriolis–Stokes force, affects the drift of the particles. The energy and momentum fluxes, as well as the Stokes drift, depend on the directional wave spectrum obtained from a wave model. As a first test, the depth and velocity scales from the model are compared with analytical solutions based on a constant eddy viscosity (i.e., classical Ekman theory. Secondly, the model is applied to a case in which we investigate the oil drift after an oil spill off the west coast of Norway in 2007. During this accident the average net drift of oil was observed to be both slower and more deflected away from the wind direction than predicted by oil-drift models. In this case, using wind and wave forcing from the ERA Interim archive it is shown that the wave effects are important for the resultant drift and have the potential to improve drift forecasting.
Particle acceleration by coronal and interplanetary shock waves
International Nuclear Information System (INIS)
Pesses, M.E.
1982-01-01
Utilizing many years of observation from deep space and near-earth spacecraft a theoretical understanding has evolved on how ions and electrons are accelerated in interplanetary shock waves. This understanding is now being applied to solar flare-induced shock waves propagating through the solar atmosphere. Such solar flare phenomena as gamma-ray line and neutron emissions, interplanetary energetic electron and ion events, and Type II and moving Type IV radio bursts appear understandable in terms of particle acceleration in shock waves
Transport with three-particle interaction
International Nuclear Information System (INIS)
Morawetz, K.
2000-01-01
Starting from a point - like two - and three - particle interaction the kinetic equation is derived. While the drift term of the kinetic equation turns out to be determined by the known Skyrme mean field the collision integral appears in two - and three - particle parts. The cross section results from the same microscopic footing and is naturally density dependent due to the three - particle force. By this way no hybrid model for drift and cross section is needed for nuclear transport. The resulting equation of state has besides the mean field correlation energy also a two - and three - particle correlation energy which both are calculated analytically for the ground state. These energies contribute to the equation of state and lead to an occurrence of a maximum at 3 times nuclear density in the total energy. (author)
Zacharegkas, Georgios; Isliker, Heinz; Vlahos, Loukas
2016-11-01
The limitation of the Quasilinear Theory (QLT) to describe the diffusion of electrons and ions in velocity space when interacting with a spectrum of large amplitude electrostatic Langmuir, Upper and Lower hybrid waves, is analyzed. We analytically and numerically estimate the threshold for the amplitude of the waves above which the QLT breaks down, using a test particle code. The evolution of the velocity distribution, the velocity-space diffusion coefficients, the driven current, and the heating of the particles are investigated, for the interaction with small and large amplitude electrostatic waves, that is, in both regimes, where QLT is valid and where it clearly breaks down.
Particle acceleration by Alfven wave turbulence in radio galaxies
International Nuclear Information System (INIS)
Eilek, J.A.
1986-01-01
Radio galaxies show evidence for acceleration of relativistic electrons locally within the diffuse radio luminous plasma. One likely candidate for the reacceleration mechanism is acceleration by magnetohydrodynamic turbulence which exists within the plasma. If Alfven waves are generated by a fluid turbulent cascade described by a power law energy-wavenumber spectrum, the particle spectrum in the presence of synchrotron losses will evolve towards an asymptotic power law which agrees with the particle spectra observed in these sources
New particle accelerations by magnetized plasma shock waves
International Nuclear Information System (INIS)
Takeuchi, Satoshi
2005-01-01
Three mechanisms concerning particle accelerations are proposed to account for the high energy of cosmic rays. A model of magnetized plasma clouds is used to simulate a shock-type wave. The attainable energies of test particles colliding with the moving magnetic clouds are investigated by analytical and numerical methods for the three mechanisms. The magnetic trapping acceleration is a new type of particle trapping and acceleration in which, in principle, the test particle is accelerated indefinitely; hence, this mechanism surpasses the Fermi-type acceleration. In the single-step acceleration, the test particle obtains a significant energy gain even though it only experiences a single collision. Lastly, there is the bouncing acceleration by which the test particle is substantially accelerated due to repeated collisions
Directory of Open Access Journals (Sweden)
M. Haghgo
2007-08-01
Full Text Available Utilizing polymeric materials for damping mechanical waves is of great importance in various fields of applications such as military camouflage, prevention of structural vibrational energy transfer, and noise attenuation. This ability originates from segmental dynamics of chain-like polymer molecules. Damping properties of styrene-butadiene rubbercontaining 10 wt% of monosize polystyrene particles with different diameters (from 80 nm to 500 μm was investigated in the frequency range of vibration, sound, and ultrasound via dynamic mechanical thermal analysis, normalsound adsorption test, and ultrasound attenuation coefficient measurement. The obtained results indicated that for different systems, containing different sizes of polystyrene particles, the area under the damping curve does not show significant change comparing to the neat SBR in the frequency range studied. However, addition of polystyrene particles, specifically nanosized particles, resulted in emergence of a secondary glass transition temperature which could be attributed to the modified dynamics of a layer of matrix molecules near the surface of PS particles. In the range of sound frequency, 0.5 to 6.3 kHz, the maximum damping was observed for the system containing polystyrene nanoparticles. However the single damping curve of neat SBR was separated into two or even three distinct curves owing to the presence of the particles. The maximum damping in the ultrasound frequency range was found for the system containing 0.5 mm polystyrene particles. This is attributed to different contributions from matrix chains dynamics and the reflection of mechanical waves from particles-matrix interface at different frequency ranges. On other words, the increase in the glass transition temperature of the elastomeric matrix phase with increasing the mechanical wave frequency causes a reduction in the contribution from matrix chains dynamics while the contribution due to diffraction from dispersed
Pion-pion interactions in particle physics
Energy Technology Data Exchange (ETDEWEB)
Martin, B R; Morgan, D; Shaw, G
1976-01-01
The aim of the book is to review the experimental and theoretical work on the processes involving pion-pion interactions. Sources of information on pion-pion scattering are examined, including pion production, dipion exchange, and weak and electromagnetic interactions. The theory and models of pion-pion scattering are discussed with reference to fixed momentum transfer, partial wave amplitudes, models and phenomenology, dynamical and field theoretic models, finite-energy sum rules, duality and the Veneziano model, resonance spectra and lastly, predictions from current algebra.
Interactive visual exploration of a trillion particles
Schatz, Karsten
2017-03-10
We present a method for the interactive exploration of tera-scale particle data sets. Such data sets arise from molecular dynamics, particle-based fluid simulation, and astrophysics. Our visualization technique provides a focus+context view of the data that runs interactively on commodity hardware. The method is based on a hybrid multi-scale rendering architecture, which renders the context as a hierarchical density volume. Fine details in the focus are visualized using direct particle rendering. In addition, clusters like dark matter halos can be visualized as semi-transparent spheres enclosing the particles. Since the detail data is too large to be stored in main memory, our approach uses an out-of-core technique that streams data on demand. Our technique is designed to take advantage of a dual-GPU configuration, in which the workload is split between the GPUs based on the type of data. Structural features in the data are visually enhanced using advanced rendering and shading techniques. To allow users to easily identify interesting locations even in overviews, both the focus and context view use color tables to show data attributes on the respective scale. We demonstrate that our technique achieves interactive performance on a one trillionpar-ticle data set from the DarkSky simulation.
Analysis of sediment particle velocity in wave motion based on wave flume experiments
Krupiński, Adam
2012-10-01
The experiment described was one of the elements of research into sediment transport conducted by the Division of Geotechnics of West-Pomeranian University of Technology. The experimental analyses were performed within the framework of the project "Building a knowledge transfer network on the directions and perspectives of developing wave laboratory and in situ research using innovative research equipment" launched by the Institute of Hydroengineering of the Polish Academy of Sciences in Gdańsk. The objective of the experiment was to determine relations between sediment transport and wave motion parameters and then use the obtained results to modify formulas defining sediment transport in rivers, like Ackers-White formula, by introducing basic parameters of wave motion as the force generating bed material transport. The article presents selected results of the experiment concerning sediment velocity field analysis conducted for different parameters of wave motion. The velocity vectors of particles suspended in water were measured with a Particle Image Velocimetry (PIV) apparatus registering suspended particles in a measurement flume by producing a series of laser pulses and analysing their displacement with a high-sensitivity camera connected to a computer. The article presents velocity fields of suspended bed material particles measured in the longitudinal section of the wave flume and their comparison with water velocity profiles calculated for the definite wave parameters. The results presented will be used in further research for relating parameters essential for the description of monochromatic wave motion to basic sediment transport parameters and "transforming" mean velocity and dynamic velocity in steady motion to mean wave front velocity and dynamic velocity in wave motion for a single wave.
Saint-Michel, Brice; Georgelin, Marc; Deville, Sylvain; Pocheau, Alain
2017-06-13
The interaction of solidification fronts with objects such as particles, droplets, cells, or bubbles is a phenomenon with many natural and technological occurrences. For an object facing the front, it may yield various fates, from trapping to rejection, with large implications regarding the solidification pattern. However, whereas most situations involve multiple particles interacting with each other and the front, attention has focused almost exclusively on the interaction of a single, isolated object with the front. Here we address experimentally the interaction of multiple particles with a solidification front by performing solidification experiments of a monodisperse particle suspension in a Hele-Shaw cell with precise control of growth conditions and real-time visualization. We evidence the growth of a particle layer ahead of the front at a close-packing volume fraction, and we document its steady-state value at various solidification velocities. We then extend single-particle models to the situation of multiple particles by taking into account the additional force induced on an entering particle by viscous friction in the compacted particle layer. By a force balance model this provides an indirect measure of the repelling mean thermomolecular pressure over a particle entering the front. The presence of multiple particles is found to increase it following a reduction of the thickness of the thin liquid film that separates particles and front. We anticipate the findings reported here to provide a relevant basis to understand many complex solidification situations in geophysics, engineering, biology, or food engineering, where multiple objects interact with the front and control the resulting solidification patterns.
Collisionless shocks and upstream waves and particles: Introductory remarks
International Nuclear Information System (INIS)
Kennel, C.F.
1981-01-01
We discuss more aspects of collisionless shock theory that might be pertinent to the problem of upstream waves and particles. It is hoped that our qualititive remarks may be a useful guide for the general reader as he goes through the detailed papers to come
Wave-particle duality in a quark model
International Nuclear Information System (INIS)
Gudder, S.P.
1984-01-01
A quark model based on finite-dimensional quantum mechanics is presented. Observables associated with color, flavor, charge, and spin are considered. Using these observables, quark and baryon Hamiltonians are constructed. Wave-particle dualities in this model are pointed out. (Auth.)
The gravitational shock wave of a massless particle
Hooft, G. 't; Dray, T
1985-01-01
The (spherical) gravitational shock wave due to a massless particle moving at the speed of light along the horizon of the Schwarzchild black hole is obtained. Special cases of our procedure yield previous results by Aichelburg and Sexl[1] for a photon in Minkowski vpace and by Penrose [2] for
Spherical wave particle velocities in geologic materials from laboratory experiments
International Nuclear Information System (INIS)
Cizek, J.C.; Florence, A.L.
1983-01-01
Particle velocity records that describe spherical waves in rock simulants, tuffs, salt, and granite have been obtained in laboratory experiments. The records aid the modeling of constitutive equations for continuum mechanics codes used in DNA containment research. The technique has also been applied to investigate containment-related problems involving material poperties, failure criteria, scaling, decoupling, and residual strain field relaxation. 22 figures
Fundamental theories of waves and particles formulated without classical mass
Fry, J. L.; Musielak, Z. E.
2010-12-01
Quantum and classical mechanics are two conceptually and mathematically different theories of physics, and yet they do use the same concept of classical mass that was originally introduced by Newton in his formulation of the laws of dynamics. In this paper, physical consequences of using the classical mass by both theories are explored, and a novel approach that allows formulating fundamental (Galilean invariant) theories of waves and particles without formally introducing the classical mass is presented. In this new formulation, the theories depend only on one common parameter called 'wave mass', which is deduced from experiments for selected elementary particles and for the classical mass of one kilogram. It is shown that quantum theory with the wave mass is independent of the Planck constant and that higher accuracy of performing calculations can be attained by such theory. Natural units in connection with the presented approach are also discussed and justification beyond dimensional analysis is given for the particular choice of such units.
Wave-particle duality? not in optical computing
Caulfield, H. John
2011-09-01
Metaphysics has only one absolute requirement: It must account for the known physics. But many metaphysics account for light and they cannot all be right. We have only one metaphysical principle that is widely accepted (Einstein's minimum simplicity rule) and it gives no one answer. Even if we could enforce it, how would we prove its validity without a (meta)3principle? People like me who work with light are never confused about whether we are dealing with a particle or a wave. I find it useful to view light in terms even broader than the usual wave-particle description. I add a third kind of wave that is not measurable but also not restricted by the physics of the measurable. I find it difficult to account for light any other way.
Resonant and non-resonant whistlers-particle interaction in the radiation belts
E. Camporeale (Enrico)
2015-01-01
htmlabstractWe study the wave-particle interactions between lower band chorus whistlers and an anisotropic tenuous population of relativistic electrons. We present the first direct comparison of first-principle Particle-in-Cell (PIC) simulations with a quasi-linear diffusion code. In the PIC
Resonant and non-resonant whistlers-particle interaction in the radiation belts
E. Camporeale (Enrico)
2014-01-01
htmlabstractWe study the wave-particle interactions between lower band chorus whistlers and an anisotropic tenuous population of relativistic electrons. We present the first direct comparison of first-principle Particle-in-Cell (PIC) simulations with a quasi-linear diffusion code, in this context.
Absorption of lower hybrid waves by alpha particles in ITER
International Nuclear Information System (INIS)
Imbeaux, F.; Peysson, Y.; Eriksson, L.G.
2003-01-01
Absorption of lower hybrid (LH) waves by alpha particles may reduce significantly the current drive efficiency of the waves in a reactor or burning plasma experiment. This absorption is quantified for ITER using the ray-tracing+2D relativistic Fokker-Planck code Delphine. The absorption is calculated as a function of the superthermal alpha particle density, which is constant in these simulations, for two candidate frequencies for the LH system of ITER. Negligible absorption by alpha particles at 3.7 GHz requires n(alpha,supra) = 7.5 10 16 m -3 , while no significant impact on the driven current is found at 5 GHz, even if n(alpha,supra) = 1.5 10 18 m -3 . (authors)
International Nuclear Information System (INIS)
Fivaz, M.; Fasoli, A.; Appert, K.; Trans, T.M.; Tran, M.Q.; Skiff, F.
1993-08-01
Dynamical chaos is produced by the interaction between plasma particles and two electrostatic waves. Experiments performed in a linear magnetized plasma and a 1D particle-in-cell simulation agree qualitatively: above a threshold wave amplitude, ion stochastic diffusion and heating occur on a fast time scale. Self-consistency appears to limit the extent of the heating process. (author) 5 figs., 18 refs
Scattering of electromagnetic waves into plasma oscillations via plasma particles
International Nuclear Information System (INIS)
Lin, A.T.; Dawson, J.M.
1975-01-01
A plasma subjected to an intense electromagnetic wave can exhibit a large number of parametric instabilities. An interesting example which has received little attention is the decay of the electromagnetic wave into a plasma oscillation with the excess energy and momentum being carried off by electrons. This process has been simulated on a one-and-two-halves dimensional electromagnetic code. The incident electromagnetic wave had a frequency near the plasma frequency so that decay into a plasma oscillation and a backscattered electromagnetic wave was excluded. As expected, the threshold for this instability was very large , so it is unlikely that this instability is competitive in most laser plasmas. Nevertheless, the physical mechanism involved provides a means for absorption of laser light and acceleration of particles in a plasma containing large amplitude plasma oscillations
Capillary interactions in nano-particle suspensions
International Nuclear Information System (INIS)
Bossev, D.P.; Warren, G.
2009-01-01
We have investigated the structures formed by colloidal particles suspended in solvents at volume fractions below 10% and interacting through capillary bridges. Such systems resemble colloidal gas of sticky nano-spheres that form pearl-necklace like chains that, in turn, induce strong viscoelasticity due to the formation of 3-D fractal network. The capillary force dominates the electrostatic and Van der Waals forces in solutions and can bridge multiple particles depending of the volume of the capillary bridge. We have investigated the morphology of the structures formed at different fractions of the bridging fluid. Small-angle neutron scattering (SANS) is used to study nanoparticles with an average diameter of 10 nm in polar and non-polar organic solvents at ambient temperatures. SANS intensity as a function of the scattering vector is analyzed as a product of a form factor, that depends on the particle shape, and a structure factor, that characterizes the interparticle inter reactions. The interaction of particles in polar solvents is considered to be through electrostatic repulsion and the data is successfully fitted by Hayter-Penfold mean spherical approximation (HPMSA). Computer simulations of a pearl necklace-like chain of spheres is conducted to explain the structure factor when capillary bridges are present. Alternatively, we have analyzed the slope of the intensity at low scattering vector in a double logarithmic plot to determine the dimension of the fractal structures formed by the particles at different volume fraction of the bridging fluid. We have also studied the properties of the capillary bridge between a pair of particles. The significance of this study is to explore the possibility of using capillary force as a tool to engineer new colloidal structures and materials in solutions and to optimize their viscoelastic properties. (author)
Coordinate asymptotics of the (3→3) wave functions for a three charged particle system
International Nuclear Information System (INIS)
Merkur'ev, S.P.
1977-01-01
Coordinate asymptotics of the (3 → 3) wave functions for three particles system with Coulomb interaction in the scattering problem is plotted. (3 → 3) and (3 → 2) process cases are considered, when the particles are not connected at the initial state. For coordinate asymptotics plotting the basis functions are used which meet Schroedinger equation in the eikonal approximation. The wave functions coordinate asymptotics plotting method is described far from special directions. Wave function asymptotical form is studied in the range of special directions and (3 → 3) scattering amplitude singularities are described. All data are given in accordance with the system with 2 charged particles only. The model in question is of special interest because of the described ppn system the studying of which is of great importance in nuclear physics. Final formulae are discussed for the most general case of three charged particles. Boundary problems for Schroedinger equation are shown to give the only way of definition for the (3 → 3) wave functions. It is pointed out that in special directions wave function coordinate asymptotics is presented with accuracy that gives the possibility to set such a boundary problem
Are snakes particles or waves? Scattering of a limbless locomotor through a single slit
Qian, Feifei; Dai, Jin; Gong, Chaohui; Choset, Howie; Goldman, Daniel
Droplets on vertically vibrated fluid surfaces can walk and diffract through a single slit by a pilot wave hydrodynamic interaction [Couder, 2006; Bush, 2015]. Inspired by the correspondence between emergent macroscale dynamics and phenomena in quantum systems, we tested if robotic snakes, which resemble wave packets, behave emergently like particles or waves when interacting with an obstacle. In lab experiments and numerical simulations we measured how a multi-module snake-like robot swam through a single slit. We controlled the snake undulation gait as a fixed serpenoid traveling wave pattern with varying amplitude and initial phase, and we examined the snake trajectory as it swam through a slit with width d. Robot trajectories were straight before interaction with the slit, then exited at different scattering angle θ after the interaction due to a complex interaction of the body wave with the slit. For fixed amplitude and large d, the snake passed through the slit with minimal interaction and theta was ~ 0 . For sufficiently small d, θ was finite and bimodally distributed, depending on the initial phase. For intermediate d, θ was sensitive to initial phase, and the width of the distribution of θ increased with decreasing d.
Interaction between colloidal particles. Literature Review
Energy Technology Data Exchange (ETDEWEB)
Longcheng Liu; Neretnieks, Ivars (Royal Inst. of Technology, Stockholm (Sweden). School of Chemical Science and Engineering, Dept. of Chemical Engineering and Technology)
2010-02-15
This report summarises the commonly accepted theoretical basis describing interaction between colloidal particles in an electrolyte solution. The two main forces involved are the van der Waals attractive force and the electrical repulsive force. The report describes in some depth the origin of these two forces, how they are formulated mathematically as well as how they interact to sometimes result in attraction and sometimes in repulsion between particles. The report also addresses how the mathematical models can be used to quantify the forces and under which conditions the models can be expected to give fair description of the colloidal system and when the models are not useful. This report does not address more recent theories that still are discussed as to their applicability, such as ion-ion correlation effects and the Coulombic attraction theory (CAT). These and other models will be discussed in future reports
Depinning of interacting particles in random media
Zapperi, Stefano; Andrade, José S., Jr.; Mendes Filho, Josué
2000-06-01
We study the overdamped motion of interacting particles in a random medium using the model introduced by Pla and Nori [Phys. Rev. Lett. 67, 919 (1991)]. We investigate the associated depinning transition by numerical integration of the equation of motion and show evidence that the model is in the same universality class of a driven elastic chain on a rough substrate. We discuss the implications of these results for flux line motion in type-II superconductors.
Stability, energetic particles, waves, and current drive summary
International Nuclear Information System (INIS)
Stambaugh, R.D.
2005-01-01
This is the summary paper for the subjects of plasma stability, energetic particles, waves, and current drive for the 20th IAEA Fusion Energy Conference, 1-6 November 2004, Vilamoura, Portugal. Material summarized herein was drawn from 65 contributed papers and 21 overview papers. The distribution of contributed papers by subjects is shown. Significant advances were reported on the principal instabilities in magnetically confined plasmas, even looking forward to the burning plasma state. Wave-plasma physics is maturing and novel methods of current drive and noninductive current generation are being developed. (author)
Probing α-particle wave functions using (rvec d,α) reactions
International Nuclear Information System (INIS)
Crosson, E.R.; Lemieux, S.K.; Ludwig, E.J.; Thompson, W.J.; Bisenberger, M.; Hertenberger, R.; Hofer, D.; Kader, H.; Schiemenz, P.; Graw, G.; Eiro, A.M.; Santos, F.D.
1993-01-01
Wave functions of the α particle corresponding to different S- and D-state deuteron-deuteron overlaps, left-angle dd|α right-angle, were investigated using exact finite-range distorted-wave Born-approximation (DWBA) analyses of (rvec d,α) reactions. Cross sections, vector, and tensor-analyzing powers were measured for (rvec d,α) reactions populating the lowest J π =7 + state in 56 Co at bombarding energies E d of 16 and 22 MeV, the lowest 7 + state in 48 Sc at E d =16 MeV, and the lowest 7 + state in 46 Sc at E d =22 MeV. We find that DWBA analyses of tensor-analyzing powers produce satisfactory agreement with the data and that A xx is especially sensitive to the D-state component of α-particle wave functions generated by different realistic nucleon-nucleon interactions
Pontalier, Q.; Lhoumeau, M.; Milne, A. M.; Longbottom, A. W.; Frost, D. L.
2018-04-01
Experiments show that when a high-explosive charge with embedded particles or a charge surrounded by a layer of liquid or granular material is detonated, the flow generated is perturbed by the motion of the particles and the blast wave profile differs from that of an ideal Friedlander form. Initially, the blast wave overpressure is reduced due to the energy dissipation resulting from compaction, fragmentation, and heating of the particle bed, and acceleration of the material. However, as the blast wave propagates, particle-flow interactions collectively serve to reduce the rate of decay of the peak blast wave overpressure. Computations carried out with a multiphase hydrocode reproduce the general trends observed experimentally and highlight the transition between the particle acceleration/deceleration phases, which is not accessible experimentally, since the particles are obscured by the detonation products. The dependence of the particle-blast interaction and the blast mitigation effectiveness on the mitigant to explosive mass ratio, the particle size, and the initial solid volume fraction is investigated systematically. The reduction in peak blast overpressure is, as in experiments, primarily dependent on the mass ratio of material to explosive, with the particle size, density, and initial porosity of the particle bed playing secondary roles. In the near field, the blast overpressure decreases sharply with distance as the particles are accelerated by the flow. When the particles decelerate due to drag, energy is returned to the flow and the peak blast overpressure recovers and reaches values similar to that of a bare explosive charge for low mass ratios. Time-distance trajectory plots of the particle and blast wave motion with the pressure field superimposed, illustrate the weak pressure waves generated by the motion of the particle layer which travel upstream and perturb the blast wave motion. Computation of the particle and gas momentum flux in the multiphase
Pontalier, Q.; Lhoumeau, M.; Milne, A. M.; Longbottom, A. W.; Frost, D. L.
2018-05-01
Experiments show that when a high-explosive charge with embedded particles or a charge surrounded by a layer of liquid or granular material is detonated, the flow generated is perturbed by the motion of the particles and the blast wave profile differs from that of an ideal Friedlander form. Initially, the blast wave overpressure is reduced due to the energy dissipation resulting from compaction, fragmentation, and heating of the particle bed, and acceleration of the material. However, as the blast wave propagates, particle-flow interactions collectively serve to reduce the rate of decay of the peak blast wave overpressure. Computations carried out with a multiphase hydrocode reproduce the general trends observed experimentally and highlight the transition between the particle acceleration/deceleration phases, which is not accessible experimentally, since the particles are obscured by the detonation products. The dependence of the particle-blast interaction and the blast mitigation effectiveness on the mitigant to explosive mass ratio, the particle size, and the initial solid volume fraction is investigated systematically. The reduction in peak blast overpressure is, as in experiments, primarily dependent on the mass ratio of material to explosive, with the particle size, density, and initial porosity of the particle bed playing secondary roles. In the near field, the blast overpressure decreases sharply with distance as the particles are accelerated by the flow. When the particles decelerate due to drag, energy is returned to the flow and the peak blast overpressure recovers and reaches values similar to that of a bare explosive charge for low mass ratios. Time-distance trajectory plots of the particle and blast wave motion with the pressure field superimposed, illustrate the weak pressure waves generated by the motion of the particle layer which travel upstream and perturb the blast wave motion. Computation of the particle and gas momentum flux in the multiphase
Is wave-particle objectivity compatible with determinism and locality?
Ionicioiu, Radu; Jennewein, Thomas; Mann, Robert B; Terno, Daniel R
2014-09-26
Wave-particle duality, superposition and entanglement are among the most counterintuitive features of quantum theory. Their clash with our classical expectations motivated hidden-variable (HV) theories. With the emergence of quantum technologies, we can test experimentally the predictions of quantum theory versus HV theories and put strong restrictions on their key assumptions. Here, we study an entanglement-assisted version of the quantum delayed-choice experiment and show that the extension of HV to the controlling devices only exacerbates the contradiction. We compare HV theories that satisfy the conditions of objectivity (a property of photons being either particles or waves, but not both), determinism and local independence of hidden variables with quantum mechanics. Any two of the above conditions are compatible with it. The conflict becomes manifest when all three conditions are imposed and persists for any non-zero value of entanglement. We propose an experiment to test our conclusions.
Alpha-particle simulation using NBI beam and ICRF wave
International Nuclear Information System (INIS)
Ogawa, Y.; Hamada, Y.
1984-07-01
A new idea to produce the distribution function similar to that of alpha-particles in an ignited plasma has been proposed. This concept is attributed to the acceleration of the injected beam up to about 1 MeV/nucleon by the ICRF wave with cyclotron higher harmonics. This new method makes it possible to perform the simulation experiments for alpha-particles under the condition of moderate plasma parameters (e.g., Tsub(e) = 4 keV, nsub(e) = 3.5x10 19 m -3 and B sub(T) = 3 T). And it is found that 3ωsub(ci) ICRF wave is preferable compared with other cyclotron harmonics, from the viewpoints of the effective tail formation with smaller bulk ion heating and lower amplitude of the applied electric field. The formula for the maximum energy of the extended beam is also derived. (author)
Seismic wave interaction with underground cavities
Schneider, Felix M.; Esterhazy, Sofi; Perugia, Ilaria; Bokelmann, Götz
2016-04-01
Realization of the future Comprehensive Nuclear Test Ban Treaty (CTBT) will require ensuring its compliance, making the CTBT a prime example of forensic seismology. Following indications of a nuclear explosion obtained on the basis of the (IMS) monitoring network further evidence needs to be sought at the location of the suspicious event. For such an On-Site Inspection (OSI) at a possible nuclear test site the treaty lists several techniques that can be carried out by the inspection team, including aftershock monitoring and the conduction of active seismic surveys. While those techniques are already well established, a third group of methods labeled as "resonance seismometry" is less well defined and needs further elaboration. A prime structural target that is expected to be present as a remnant of an underground nuclear explosion is a cavity at the location and depth the bomb was fired. Originally "resonance seismometry" referred to resonant seismic emission of the cavity within the medium that could be stimulated by an incident seismic wave of the right frequency and observed as peaks in the spectrum of seismic stations in the vicinity of the cavity. However, it is not yet clear which are the conditions for which resonant emissions of the cavity could be observed. In order to define distance-, frequency- and amplitude ranges at which resonant emissions could be observed we study the interaction of seismic waves with underground cavities. As a generic model for possible resonances we use a spherical acoustic cavity in an elastic full-space. To solve the forward problem for the full elastic wave field around acoustic spherical inclusions, we implemented an analytical solution (Korneev, 1993). This yields the possibility of generating scattering cross-sections, amplitude spectrums and synthetic seismograms for plane incident waves. Here, we focus on the questions whether or not we can expect resonant responses in the wave field scattered from the cavity. We show
Waves in plasmas (part 1 - wave-plasma interaction general background)
International Nuclear Information System (INIS)
Dumont, R.
2004-01-01
This document gathers a series of transparencies presented in the framework of the week-long lectures 'hot plasmas 2004' and dedicated to the physics of wave-plasma interaction. The structure of this document is as follows: 1) wave and diverse plasmas, 2) basic equations (Maxwell equations), 3) waves in a fluid plasma, and 4) waves in a kinetic plasma (collisionless plasma)
High frequency single mode traveling wave structure for particle acceleration
Energy Technology Data Exchange (ETDEWEB)
Ivanyan, M.I.; Danielyan, V.A.; Grigoryan, B.A.; Grigoryan, A.H. [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia); Tsakanian, A.V. [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia); Technische Universität Darmstadt, Institut TEMF, 64289 Darmstadt (Germany); Tsakanov, V.M., E-mail: tsakanov@asls.candle.am [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia); Vardanyan, A.S.; Zakaryan, S.V. [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia)
2016-09-01
The development of the new high frequency slow traveling wave structures is one of the promising directions in accomplishment of charged particles high acceleration gradient. The disc and dielectric loaded structures are the most known structures with slowly propagating modes. In this paper a large aperture high frequency metallic two-layer accelerating structure is studied. The electrodynamical properties of the slowly propagating TM{sub 01} mode in a metallic tube with internally coated low conductive thin layer are examined.
Analysis of the dynamic interaction between SVOCs and airborne particles
DEFF Research Database (Denmark)
Liu, Cong; Shi, Shanshan; Weschler, Charles J.
2013-01-01
A proper quantitative understanding of the dynamic interaction between gas-phase semivolatile organic compounds (SVOCs) and airborne particles is important for human exposure assessment and risk evaluation. Questions regarding how to properly address gas/particle interactions have introduced...
Particle-wave discrimination in Poisson spot experiments
International Nuclear Information System (INIS)
Reisinger, T; Bracco, G; Holst, B
2011-01-01
Matter-wave interferometry has been used extensively over the last few years to demonstrate the quantum-mechanical wave nature of increasingly larger and more massive particles. We have recently suggested the use of the historical Poisson spot setup to test the diffraction properties of larger objects. In this paper, we present the results of a classical particle van der Waals (vdW) force model for a Poisson spot experimental setup and compare these to Fresnel diffraction calculations with a vdW phase term. We include the effect of disc-edge roughness in both models. Calculations are performed with D 2 and with C 70 using realistic parameters. We find that the sensitivity of the on-axis interference/focus spot to disc-edge roughness is very different in the two cases. We conclude that by measuring the intensity on the optical axis as a function of disc-edge roughness, it can be determined whether the objects behave as de Broglie waves or classical particles. The scaling of the Poisson spot experiment to larger molecular masses is, however, not as favorable as in the case of near-field light-grating-based interferometers. Instead, we discuss the possibility of studying the Casimir-Polder potential using the Poisson spot setup.
Worldline path integrals for a Dirac particle in a weak gravitational plane wave
International Nuclear Information System (INIS)
Haouat, S.; Chetouani, L.
2008-01-01
The problem of a relativistic spinning particle interacting with a weak gravitational plane wave in (3+1) dimensions is formulated in the frame work of covariant supersymmetric path integrals. The relative Green function is expressed through a functional integral over bosonic trajectories that describe the external motion and fermionic variables that describe the spin degrees of freedom. The (3+1) dimensional problem is reduced to the (1+1) dimensional one by using an identity. Next, the relative propagator is exactly calculated and the wave functions are extracted. (orig.)
Interaction of plasma vortices with resonant particles
DEFF Research Database (Denmark)
Jovanovic, D.; Pécseli, Hans; Juul Rasmussen, J.
1990-01-01
Kinetic effects associated with the electron motion along magnetic field lines in low‐beta plasmas are studied. Using the gyrokinetic description of electrons, a kinetic analog of the reduced magnetohydrodynamic equations is derived, and it is shown that in the strongly nonlinear regime...... particles. The evolution equations indicate the possibility of excitation of plasma vortices by electron beams....... they possess localized solutions in the form of dipolar vortices, which can efficiently interact with resonant electrons. In the adiabatic limit, evolution equations are derived for the vortex parameters, describing exchange of the energy, enstrophy, and of the Poynting vector between the vortex and resonant...
Blast wave interaction with a rigid surface
International Nuclear Information System (INIS)
Josey, T.; Whitehouse, D.R.; Ripley, R.C.; Dionne, J.P.
2004-01-01
A simple model used to investigate blast wave interactions with a rigid surface is presented. The model uses a constant volume energy source analogue to predict pressure histories at gauges located directly above the charge. A series of two-dimensional axi-symmetric CFD calculations were performed, varying the height of the charge relative to the ground. Pressure histories, along with isopycnic plots are presented to evaluate the effects of placing a charge in close proximity to a rigid surface. When a charge is placed near a solid surface the pressure histories experienced at gauges above the charge indicate the presence of two distinct pressure peaks. The first peak is caused by the primary shock and the second peak is a result of the wave reflections from the rigid surface. As the distance from the charge to the wall is increased the magnitude of the second pressure peak is reduced, provided that the distance between the charge and the gauge is maintained constant. The simple model presented is able to capture significant, predictable flow features. (author)
The VLF Wave and Particle Precipitation Mapper (VPM) Cubesat Payload Suite
Inan, U.; Linscott, I.; Marshall, R. A.; Lauben, D.; Starks, M. J.; Doolittle, J. H.
2012-12-01
The VLF Wave and Particle Precipitation Mapper (VPM) payload is under development at Stanford University for a Cubesat mission that is planned to fly in low-earth-orbit in 2015. The VPM payload suite includes a 2-meter electric-field dipole antenna; a single-axis magnetic search coil; and a two-channel relativistic electron detector, measuring both trapped and loss-cone electrons. VPM will measure waves and relativistic electrons with the following primary goals: i) develop an improved climatology of plasmaspheric hiss in the L-shell range 1 < L < 3 at all local times; ii) detect VLF waves launched by space-based VLF transmitters, as well as energetic electrons scattered by those in-situ injected waves; iii) develop an improved climatology of lightning-generated whistlers and lightning-induced electron precipitation; iv)measure waves and electron precipitation produced by ground-based VLF transmitters; and v) validate propagation and wave-particle interaction models. In this paper we outline these science objectives of the VPM payload instrument suite, and describe the payload instruments and data products that will meet these science goals.
Study on a particle separator using ultrasonic wave
International Nuclear Information System (INIS)
Lee, Young Seop; Kwon, Jae Hwa; Seo, Dae Chul; Yun, Dong Jin
2005-01-01
This paper presents the theory, design and evaluation of a smart device for the enhanced separation of particles mixed in fluid. The smart device takes advantage of the ultrasonic standing wave, which was generated by the operation of a piezoceramic PZT patch installed in the smart device. The details of the device design including the electro-acoustical modelling for separation and PZT transducer are described at the first. Based on this design, the separation device was fabricated and evaluated. In the experiments, an optical camera with a zoom lense was used to monitor the position of interested particles within the separation channel layer in the device. The electric impedance of the PZT patch bonded on the separation device was measured. The device shows a strong levitation and separation force against 50m diameter particles mixed with water at the separation channel in the device. Experimental results also showed that the device can work at both heavy and light sand particles mixed with water due to the generated standing wave field in the separation channel.
Cosmological constraints on interacting light particles
Energy Technology Data Exchange (ETDEWEB)
Brust, Christopher [Perimeter Institute for Theoretical Physics, 31 Caroline Street N, Waterloo, ON, N2L 2Y5 Canada (Canada); Cui, Yanou [Department of Physics and Astronomy, University of California, 900 University Ave, Riverside, CA, 92521 (United States); Sigurdson, Kris, E-mail: cbrust@perimeterinstitute.ca, E-mail: yanou.cui@ucr.edu, E-mail: krs@phas.ubc.ca [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 Canada (Canada)
2017-08-01
Cosmological observations are becoming increasingly sensitive to the effects of light particles in the form of dark radiation (DR) at the time of recombination. The conventional observable of effective neutrino number, N {sub eff}, is insufficient for probing generic, interacting models of DR. In this work, we perform likelihood analyses which allow both free-streaming effective neutrinos (parametrized by N {sub eff}) and interacting effective neutrinos (parametrized by N {sub fld}). We motivate an alternative parametrization of DR in terms of N {sub tot} (total effective number of neutrinos) and f {sub fs} (the fraction of effective neutrinos which are free-streaming), which is less degenerate than using N {sub eff} and N {sub fld}. Using the Planck 2015 likelihoods in conjunction with measurements of baryon acoustic oscillations (BAO), we find constraints on the total amount of beyond the Standard Model effective neutrinos (both free-streaming and interacting) of Δ N {sub tot} < 0.39 at 2σ. In addition, we consider the possibility that this scenario alleviates the tensions between early-time and late-time cosmological observations, in particular the measurements of σ{sub 8} (the amplitude of matter power fluctuations at 8 h {sup −1} Mpc), finding a mild preference for interactions among light species. We further forecast the sensitivities of a variety of future experiments, including Advanced ACTPol (a representative CMB Stage-III experiment), CMB Stage-IV, and the Euclid satellite. This study is relevant for probing non-standard neutrino physics as well as a wide variety of new particle physics models beyond the Standard Model that involve dark radiation.
International Nuclear Information System (INIS)
Solomon, Jacques
1977-01-01
This research thesis addresses convection movements of energetic ionised particles in the Earth near magnetosphere (geocentric distances of about 2 to 10 Earth radii), and the interactions between these particles and waves they may generate. The author first recalls some notions dealing with cyclotron interactions between waves and particles, gives an example of dispersion relationship for these interactions, and indicates possible approximations for simplification purposes. The author also outlines the role of the hot and cold plasma with respect to densities in the wave amplification coefficient. Then, the author reports the study of wave amplification and of particle scattering. He tries to address the problem of waves-particles interaction through a self-consistent approach, i.e. by calculating simultaneously the spectral intensity of emitted waves and the particle distribution function resulting from their scattering. He more particularly addresses the case of a non-stationary interaction (relaxation) and of a stationary interaction. Complete calculations are performed for this last case. Radial and azimuth drift movements of hot particles under the influence of magnetic and static electric fields are then taken into account [fr
Planckian Interacting Massive Particles as Dark Matter.
Garny, Mathias; Sandora, McCullen; Sloth, Martin S
2016-03-11
The standard model could be self-consistent up to the Planck scale according to the present measurements of the Higgs boson mass and top quark Yukawa coupling. It is therefore possible that new physics is only coupled to the standard model through Planck suppressed higher dimensional operators. In this case the weakly interacting massive particle miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that dark matter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that dark matter is a Planckian interacting massive particle, we show that the most natural mass larger than 0.01M_{p} is already ruled out by the absence of tensor modes in the cosmic microwave background (CMB). This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal dark matter model. Finally, we touch upon the Kaluza-Klein graviton mode as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of dark matter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of dark matter.
Wave Driven Fluid-Sediment Interactions over Rippled Beds
Foster, Diane; Nichols, Claire
2008-11-01
Empirical investigations relating vortex shedding over rippled beds to oscillatory flows date back to Darwin in 1883. Observations of the shedding induced by oscillating forcing over fixed beds have shown vortical structures to reach maximum strength at 90 degrees when the horizontal velocity is largest. The objective of this effort is to examine the vortex generation and ejection over movable rippled beds in a full-scale, free surface wave environment. Observations of the two-dimensional time-varying velocity field over a movable sediment bed were obtained with a submersible Particle Image Velocimetry (PIV) system in two wave flumes. One wave flume was full scale and had a natural sand bed and the other flume had an artificial sediment bed with a specific gravity of 1.6. Full scale observations over an irregularly rippled bed show that the vortices generated during offshore directed flow over the steeper bed form slope were regularly ejected into the water column and were consistent with conceptual models of the oscillatory flow over a backward facing step. The results also show that vortices remain coherent during ejection when the background flow stalls (i.e. both the velocity and acceleration temporarily approach zero). These results offer new insight into fluid sediment interaction over rippled beds.
Entropic Ratchet transport of interacting active Brownian particles
International Nuclear Information System (INIS)
Ai, Bao-Quan; He, Ya-Feng; Zhong, Wei-Rong
2014-01-01
Directed transport of interacting active (self-propelled) Brownian particles is numerically investigated in confined geometries (entropic barriers). The self-propelled velocity can break thermodynamical equilibrium and induce the directed transport. It is found that the interaction between active particles can greatly affect the ratchet transport. For attractive particles, on increasing the interaction strength, the average velocity first decreases to its minima, then increases, and finally decreases to zero. For repulsive particles, when the interaction is very weak, there exists a critical interaction at which the average velocity is minimal, nearly tends to zero, however, for the strong interaction, the average velocity is independent of the interaction
Entropic Ratchet transport of interacting active Brownian particles
Energy Technology Data Exchange (ETDEWEB)
Ai, Bao-Quan, E-mail: aibq@hotmail.com [Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, 510006 Guangzhou (China); He, Ya-Feng [College of Physics Science and Technology, Hebei University, 071002 Baoding (China); Zhong, Wei-Rong, E-mail: wrzhong@jnu.edu.cn [Department of Physics and Siyuan Laboratory, College of Science and Engineering, Jinan University, 510632 Guangzhou (China)
2014-11-21
Directed transport of interacting active (self-propelled) Brownian particles is numerically investigated in confined geometries (entropic barriers). The self-propelled velocity can break thermodynamical equilibrium and induce the directed transport. It is found that the interaction between active particles can greatly affect the ratchet transport. For attractive particles, on increasing the interaction strength, the average velocity first decreases to its minima, then increases, and finally decreases to zero. For repulsive particles, when the interaction is very weak, there exists a critical interaction at which the average velocity is minimal, nearly tends to zero, however, for the strong interaction, the average velocity is independent of the interaction.
Khabarova, Olga; Malandraki, Olga; Zank, Gary; Jackson, Bernard; Bisi, Mario; Desai, Mihir; Li, Gang; le Roux, Jakobus; Yu, Hsiu-Shan
2017-04-01
Recent studies of mechanisms of particle acceleration in the heliosphere have revealed the importance of the comprehensive analysis of stream-stream interactions as well as the heliospheric current sheet (HCS) - stream interactions that often occur in the solar wind, producing huge magnetic cavities bounded by strong current sheets. Such cavities are usually filled with small-scale magnetic islands that trap and re-accelerate energetic particles (Zank et al. ApJ, 2014, 2015; le Roux et al. ApJ, 2015, 2016; Khabarova et al. ApJ, 2015, 2016). Crossings of these regions are associated with unusual variations in the energetic particle flux up to several MeV/nuc near the Earth's orbit. These energetic particle flux enhancements called "atypical energetic particle events" (AEPEs) are not associated with standard mechanisms of particle acceleration. The analysis of multi-spacecraft measurements of energetic particle flux, plasma and the interplanetary magnetic field shows that AEPEs have a local origin as they are observed by different spacecraft with a time delay corresponding to the solar wind propagation from one spacecraft to another, which is a signature of local particle acceleration in the region embedded in expanding and rotating background solar wind. AEPEs are often observed before the arrival of corotating interaction regions (CIRs) or stream interaction regions (SIRs) to the Earth's orbit. When fast solar wind streams catch up with slow solar wind, SIRs of compressed heated plasma or more regular CIRs are created at the leading edge of the high-speed stream. Since coronal holes are often long-lived structures, the same CIR re-appears often for several consecutive solar rotations. At low heliographic latitudes, such CIRs are typically bounded by forward and reverse waves on their leading and trailing edges, respectively, that steepen into shocks at heliocentric distances beyond 1 AU. Energetic ion increases have been frequently observed in association with CIR
Particle dispersion and mixing induced by breaking internal gravity waves
Bouruet-Aubertot, Pascale; Koudella, C.; Staquet, C.; Winters, K. B.
2001-01-01
The purpose of this paper is to analyze diapycnal mixing induced by the breaking of an internal gravity wave — the primary wave — either standing or propagating. To achieve this aim we apply two different methods. The first method consists of a direct estimate of vertical eddy diffusion from particle dispersion while the second method relies upon potential energy budgets [Winters, K.B., Lombard, P.N., Riley, J.J., D'Asaro, E.A., 1995. J. Fluid Mech. 289, 115-128; Winters, K.B., D'Asaro, E.A., 1996. J. Fluid Mech. 317, 179-193]. The primary wave we consider is of small amplitude and is statically stable, a case for which the breaking process involves two-dimensional instabilities. The dynamics of the waves have been previously analyzed by means of two-dimensional direct numerical simulations [Bouruet-Aubertot, P., Sommeria, J., Staquet, C., 1995. J. Fluid Mech. 285, 265-301; Bouruet-Aubertot, P., Sommeria, J., Staquet, C., 1996. Dyn. Atmos. Oceans 29, 41-63; Koudella, C., Staquet, C., 1998. In: Davis, P. (Ed.), Proceedings of the IMA Conference on Mixing and Dispersion on Stably-stratified Flows, Dundee, September 1996. IMA Publication]. High resolution three-dimensional calculations of the same wave are also reported here [Koudella, C., 1999]. A local estimate of mixing is first inferred from the time evolution of sets of particles released in the flow during the breaking regime. We show that, after an early evolution dominated by shear effects, a diffusion law is reached and the dispersion coefficient is fairly independent of the initial seeding location of the particles in the flow. The eddy diffusion coefficient, K, is then estimated from the diapycnal diffusive flux. A good agreement with the value inferred from particle dispersion is obtained. This finding is of particular interest regarding the interpretation of in situ estimates of K inferred either from tracer dispersion or from microstructure measurements. Computation of the Cox number, equal to the
Particle energization by inertial Alfven wave in auroral ionosphere
Kumar, S.
2017-12-01
The role of inertial Alfven wave in auroral acceleration region and in the inertial regime to energize the plasma particles is an interesting field and widely discussed observationally as well as theoretically in recent years. In this work, we present the density perturbations by inertial Alfvén wave (AW) in the auroral ionosphere. We obtain dynamical equations for inertial AW and fast mode of AW using two-fluid model and then solve them numerically in order to analyze the localized structures and cavity formation. The ponderomotive force due to the high frequency inertial AW changes the background density and is believed to be responsible for the wave localization or for the formation of density cavities in auroral ionosphere. These density cavities are believed to be the sites for particle energization. This perturbed density channel grow with time until the modulation instability acquires steady state. We find that the density cavities are accompanied by the high amplitude magnetic fields. The amplitude of the strongest density cavity is estimated as ˜ 0.26n0 (n0 is unperturbed plasma number density). The results presented here are found consistent with the observational studies using FAST spacecraft.
Nonlinear interaction of the surface waves at a plasma boundary
International Nuclear Information System (INIS)
Dolgopolov, V.V.; El-Naggar, I.A.; Hussein, A.M.; Khalil, Sh.M.
1976-01-01
Amplitudes of electromagnetic waves with combination frequencies, radiating from the plasma boundary due to nonlinear interaction of the surface waves, have been found. Previous papers on this subject did not take into account that the tangential components of the electric field of waves with combination frequencies were discontinuous at the plasma boundary. (Auth.)
Interaction of externally-driven acoustic waves with compressible convection
International Nuclear Information System (INIS)
Jones, P.; Merryfield, W.
1992-01-01
Two-dimensional numerical simulations are used to examine the interaction of acoustic waves with a compressible convecting fluid. Acoustic waves are forced at the lower boundary of the computational domain and propagate through a three-layer system undergoing vigorous penetrative convection. Energy exchange between the wave and the fluid is analyzed using a work integral formulation
Energy Technology Data Exchange (ETDEWEB)
Frank, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1969-07-01
The aim of this work is the experimental study of the interaction between electrostatic waves and electrons in a plasma characterized by a so called 'bump in tail' distribution function. To study experimentally the mechanism of this interaction it is necessary to measure precisely the electron distribution and its evolution in space or in time. This was performed with an electrostatic separation probe which was designed especially. We measured also the evolution in space and time of the noise spectrum. We studied this mechanism in two different regimes of our discharge: - In the first case the distribution function is very close to that describing the interaction of a semi-infinite plasma with a cold beam injected at its edge. We showed that the instability resulting from this interaction is convective and that the growth of the waves results in a very important modification of the distribution function. The ionization due to the electric field related to the waves is also important. This modification is similar to that described by the quasi linear theory. The mechanism described by this theory remains then qualitatively valid in a strongly non linear case. - In the second case the conditions necessary for the quasi linear theory to be valid are satisfactorily fulfilled. It is then possible to measure, simultaneously, and precisely, the evolution of the distribution function and of the noise spectrum. From these measurements one can deduce the mechanism of the energy exchange between waves and particles and show that it is in good agreement with that described by the quasi linear theory. (author) [French] On presente ici l'etude experimentale detaillee du mecanisme de l'echange d'energie entre les oscillations e la frequence plasma des electrons et des electrons energetiques dans un plasma presentant une fonction de distribution du type a 'double bosse'. Pour realiser cette etude on a mis au point, une 'sonde a separation electrostatique' qui permet de mesurer
Modeling of MeV alpha particle energy transfer to lower hybrid waves
International Nuclear Information System (INIS)
Schivell, J.; Monticello, D.A.; Fisch, N.; Rax, J.M.
1993-10-01
The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. An initial analytic study was done by Fisch and Rax. Here the authors calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favorable for wave amplification from alpha energy. They find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this idea, the use of a lossy boundary to enhance the energy transfer, is investigated. This technique is shown to offer a large potential benefit
Auroral particle acceleration by Alfvén waves and ionospheric feedback
Lysak, R. L.; Song, Y.
2003-12-01
Recent observations, particularly by Polar and FAST, have indicated that Alfvén waves can directly accelerate auroral electrons. A model for this interaction has been developed that can describe the linear modification of the Alfvén wave profile by the kinetic effects of electrons, including acceleration and heating of the electron population. While many of the heated electrons are accelerated upward into the magnetosphere by the mirror force, a significant fraction of the input Poynting flux due to Alfvén waves can be converted into precipitating electron energy flux. An important aspect of this particle precipitation is that the hot electrons do not arrive at the ionosphere in phase with the field-aligned current, which at ionospheric altitudes is largely carried by cold electrons. This phase shift has direct implications for models of ionospheric feedback that usually assume that the precipitating flux is in phase with the field-aligned current. The effects of quasi-static electric fields can be included in the model, which will introduce new particle populations such as the effects of secondary electrons of ionospheric origin that are reflected by the parallel potential drop. The possible role of Alfvén waves trapped in the ionospheric resonator in creating small-scale auroral structures through feedback and nonlinear interactions will be discussed.
Planckian Interacting Massive Particles as Dark Matter
DEFF Research Database (Denmark)
Garny, Mathias; Sandora, McCullen; Sloth, Martin S.
2016-01-01
. In this case the WIMP miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that dark matter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that dark matter is a Planckian Interacting Massive Particle......, we show that the most natural mass larger than $0.01\\,\\textrm{M}_p$ is already ruled out by the absence of tensor modes in the CMB. This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal dark matter model. Finally, we touch upon the KK graviton mode...... as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of dark matter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of dark...
Waves and particles in the Fermi accelerator model. Numerical simulation
International Nuclear Information System (INIS)
Meplan, O.
1996-01-01
This thesis is devoted to a numerical study of the quantum dynamics of the Fermi accelerator which is classically chaotic: it is particle in a one dimensional box with a oscillating wall. First, we study the classical dynamics: we show that the time of impact of the particle with the moving wall and its energy in the wall frame are conjugated variables and that Poincare surface of sections in these variables are more understandable than the usual stroboscopic sections. Then, the quantum dynamics of this systems is studied by the means of two numerical methods. The first one is a generalization of the KKR method in the space-time; it is enough to solve an integral equation on the boundary of a space-time billiard. The second method is faster and is based on successive free propagations and kicks of potential. This allows us to obtain Floquet states which we can on one hand, compare to the classical dynamics with the help of Husimi distributions and on the other hand, study as a function of parameters of the system. This study leads us to nice illustrations of phenomenons such as spatial localizations of a wave packet in a vibrating well or tunnel effects. In the adiabatic situation, we give a formula for quasi-energies which exhibits a phase term independent of states. In this regime, there exist some particular situations where the quasi-energy spectrum presents a total quasi-degeneracy. Then, the wave packet energy can increase significantly. This phenomenon is quite surprising for smooth motion of the wall. The third part deals with the evolution of a classical wave in the Fermi accelerator. Using generalized KKR method, we show a surprising phenomenon: in most of situations (so long as the wall motion is periodic), a wave is localized exponentially in the well and its energy increases in a geometric way. (author). 107 refs., 66 figs., 5 tabs. 2 appends
[Interaction of protein with charged colloidal particles].
Durdenko, E V; Kuznetsova, S M; Basova, L V; Tikhonenko, S A; Saburova, E A
2011-01-01
The functional state of three proteins of different molecular weight (urease, lactate dehydrogenase, and hemoglobin) in the presence of the linear polyelectrolytes poly(allylamine hydrochloride) (PAA) and sodium poly(styrenesulfonate) (PSS) in the dissolved state and of the same polyelectrolytes bound to the surface of microspheres has been investigated. Microspheres were prepared by consecutive absorption of oppositely charged polyelectrolytes so that the outer layer of the shell was PAA for the acidic protein urease, and PSS for the alkaline proteins LDH and hemoglobin. It was shown that the dissolved polyelectrolyte completely inactivates all three proteins within one minute with a slight difference in the time constant. (By Hb inactivation are conventionally meant changes in the heme environment observed from the spectrum in the Soret band.) In the presence of microspheres, the proteins were adsorbed on their surface; in this case, more than 95% of the activity was retained within two hours. The proportion of the protein adsorbed on microspheres accounted for about 98% for urease, 72% for Hb, and 35% for LDH, as determined from the tryptophan fluorescence data. The interaction of hemoglobin with another type of charged colloidal particles, phospholipid vesicles, leads to the destruction of the tertiary structure of the protein, which made itself evident in the optical absorption spectra in the Soret band, as well as the spectra of tryptophan fluorescence and circular dichroism. In this case, according to circular dichroism, the percentage of alpha-helical structure of Hb was maintained. The differences in the physical and chemical mechanisms of interaction of proteins with these two types of charged colloidal particles that leads to differences in the degree of denaturing effects are discussed.
Nonlinear interactions of electromagnetic waves with the auroral ionosphere
Wong, Alfred Y.
1999-09-01
The ionosphere provides us with an opportunity to perform plasma experiments in an environment with long confinement times, very large-scale lengths, and no confining walls. The auroral ionosphere with its nearly vertical magnetic field geometry is uniquely endowed with large amount of free energy from electron and ion precipitation along the magnetic field and mega-ampere current across the magnetic field. To take advantage of this giant outdoor laboratory, two facilities HAARP and HIPAS, with frequencies ranging from the radio to optical bands, are now available for active probing of and interaction with this interesting region. The ponderomotive pressures from the self-consistent wave fields have produced significant local perturbations of density and particle distributions at heights where the incident EM frequency matches a plasma resonance. This paper will review theory and experiments covering the nonlinear phenomena of parametric decay instability to wave collapse processes. At HF frequencies plasma lenses can be created by preconditioning pulses to focus what is a normally divergent beam into a high-intensity spot to further enhance nonlinear phenomena. At optical wavelengths a large rotating liquid metal mirror is used to focus laser pulses up to a given height. Such laser pulses are tuned to the same wavelengths of selected atomic and molecular resonances, with resulting large scattering cross sections. Ongoing experiments on dual-site experiments and excitation of ELF waves will be presented. The connection of such basic studies to environmental applications will be discussed. Such applications include the global communication using ELF waves, the ozone depletion and remediation and the control of atmospheric CO2 through the use of ion cyclotron resonant heating.
A particle model of rolling grain ripples under waves
DEFF Research Database (Denmark)
Andersen, Ken Haste
2001-01-01
A simple model for the formation of rolling grain ripples on a flat sand bed by the oscillatory flow generated by a surface wave is presented. An equation of motion is derived for the individual ripples, seen as "particles," on the otherwise flat bed. The model accounts for the initial appearance...... of the ripples, the subsequent coarsening of the ripples, and the final equilibrium state. The model is related to the physical parameters of the problem, and an analytical approximation for the equilibrium spacing of the ripples is developed. It is found that the spacing between the ripples scales...
Laws of motion for interacting Yang-Mills particles
International Nuclear Information System (INIS)
Fuchs, H.
1988-01-01
Our recent Lagrangian approach to the equations of motion for test particles with internal structure can be enlarged to the laws of motion for interacting particles, at least in principle. As an example we consider the interaction of point particles endowed with a pole-dipole structure of the non-abelian charge. (author)
Particles and waves in electron optics and microscopy
Pozzi, Giulio
2016-01-01
Advances in Imaging and Electron Physics merges two long-running serials, Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. The series features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science, digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains. * Contains contributions from leading authorities on the subject matter* Informs and updates all the latest developments in the field of imaging and electron physics* Provides practitioners interested in microscopy, optics, image processing, mathematical morphology, electromagnetic fields, electron, and ion emission with a valuable resource* Features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science, and digital image pro...
On the interaction of small-scale linear waves with nonlinear solitary waves
Xu, Chengzhu; Stastna, Marek
2017-04-01
In the study of environmental and geophysical fluid flows, linear wave theory is well developed and its application has been considered for phenomena of various length and time scales. However, due to the nonlinear nature of fluid flows, in many cases results predicted by linear theory do not agree with observations. One of such cases is internal wave dynamics. While small-amplitude wave motion may be approximated by linear theory, large amplitude waves tend to be solitary-like. In some cases, when the wave is highly nonlinear, even weakly nonlinear theories fail to predict the wave properties correctly. We study the interaction of small-scale linear waves with nonlinear solitary waves using highly accurate pseudo spectral simulations that begin with a fully nonlinear solitary wave and a train of small-amplitude waves initialized from linear waves. The solitary wave then interacts with the linear waves through either an overtaking collision or a head-on collision. During the collision, there is a net energy transfer from the linear wave train to the solitary wave, resulting in an increase in the kinetic energy carried by the solitary wave and a phase shift of the solitary wave with respect to a freely propagating solitary wave. At the same time the linear waves are greatly reduced in amplitude. The percentage of energy transferred depends primarily on the wavelength of the linear waves. We found that after one full collision cycle, the longest waves may retain as much as 90% of the kinetic energy they had initially, while the shortest waves lose almost all of their initial energy. We also found that a head-on collision is more efficient in destroying the linear waves than an overtaking collision. On the other hand, the initial amplitude of the linear waves has very little impact on the percentage of energy that can be transferred to the solitary wave. Because of the nonlinearity of the solitary wave, these results provide us some insight into wave-mean flow
A study of compound particles in pion-nucleus interactions
International Nuclear Information System (INIS)
Ahmad, Tufail
2012-01-01
In this paper, the phenomenon of multiparticle production has been studied using the nuclear emulsion technique. Nuclear emulsion is a material which memorises the tracks of charged particles. When an incident particle interacts with the nuclei of the emulsion, secondary particles are produced. These secondary particles are classified into three categories viz., shower (Ns), grey (Ng) and black (Nb) particles. The investigation of particle-nucleus collisions is fundamental for understanding the nature of the interaction process. In such studies most of the attention was paid to the relativistic charged particles that is showers (1-3). From the survey of literature it is found that slow particles (grey and black) are less studied in comparison to charged shower particles. Grey particles may provide some valuable information and it may be taken as good measure of number of collisions made by the incident particle
Effects of micro-ramps on a shock wave/turbulent boundary layer interaction
Blinde, P.L.; Humble, R.A.; Van Oudheusden, B.W.; Scarano, F.
2009-01-01
Stereoscopic particle image velocimetry is used to investigate the effects of micro-ramp sub-boundary layer vortex generators, on an incident shock wave/boundary layer interaction at Mach 1.84. Single- and double-row arrangements of micro-ramps are considered. The micro-ramps have a height of 20% of
International Nuclear Information System (INIS)
Ju Guoxing; Xiang Yang; Ren Zhongzhou
2006-01-01
The properties of the s-wave for a quasi-free particle with position-dependent mass (PDM) have been discussed in details. Differed from the system with constant mass in which the localization of the s-wave for the free quantum particle around the origin only occurs in two dimensions, the quasi-free particle with PDM can experience attractive forces in D dimensions except D = 1 when its mass function satisfies some conditions. The effective mass of a particle varying with its position can induce effective interaction, which may be attractive in some cases. The analytical expressions of the eigenfunctions and the corresponding probability densities for the s-waves of the two- and three-dimensional systems with a special PDM are given, and the existences of localization around the origin for these systems are shown.
Consequences of repeated discovery and benign neglect of non-interaction of waves (NIW)
Roychoudhuri, ChandraSekhar
2017-08-01
This paper presents the historical background behind the repeated discovery and repeated ignoring of the generic important property of all propagating waves, the Non-Interaction of Waves (NIW). The focus will be on the implications of NIW in most of the major optical phenomena with brief hints of importance. We argue that the prevailing postulate of wave-particle duality becomes unnecessary, once we accept NIW. Semi-classical model of treating light-matter interactions should be the preferred approach since the quantumness actually arises from within the structure of the energy levels (bands) in materials. Waves, and wave equations, do not support bullet-like propagation. We follow the historical trend starting from the tenth century physicist Alhazen, to the seventeenth century Newton and Huygens, then to the nineteenth century Young and Fresnel. Then we jump to twentieth century physicists Planck, Einstein, Bose, Dirac and Feynman. Had we recognized and appreciated NIW property of waves from the time of Alhazen, the evolutionary history of physics would have been dramatically different from what we have today. The prevailing dominance of the postulate of wave-particle duality is keeping us confused from seeking out actual reality; and hence, we should abandon this concept and search out better models. The paper demonstrates that NIW provides us with a platform for deeper understanding of the nature of EM waves that we have missed; it is not just semantics.
Ulysses Observations of Nonlinear Wave-wave Interactions in the ...
Indian Academy of Sciences (India)
tribpo
The Ulysses Unified Radio and Plasma Wave Experiment. (URAP) has observed Langmuir, ... gesting that strong turbulence processes, such as modulational instability and soliton formation, often coexist ... Solar and interplanetary type III radio bursts, which occur at the fundamental and the second harmonic of the electron ...
International Nuclear Information System (INIS)
El Naggar, I.A.; Hussein, A.M.; Khalil, Sh.M.
1992-09-01
Electromagnetic waves radiated with combination frequencies from a semi-bounded plasma due to nonlinear interaction of radiation with surface wave (both of P-polarization) has been investigated. Waves are radiated both into vacuum and plasma are found to be P-polarized. We take into consideration the continuity at the plasma boundary of the tangential components of the electric field of the waves. The case of normal incidence of radiation and rarefield plasma layer is also studied. (author). 7 refs
Cellular structures in a system of interacting particles
International Nuclear Information System (INIS)
Lev, B.I.
2009-01-01
The general description of the formation of a cellular structure in the system of interacting particles is proposed. The analytical results for possible cellular structures in the usual colloidal systems, systems of particles immersed in a liquid crystal, and gravitational systems have been presented. It is shown that the formation of a cellular structure in all systems of interacting particles at different temperatures and concentrations of particles has the same physical nature
Probing α-particle wave functions by (d,α) tensor analyzing powers
International Nuclear Information System (INIS)
Crosson, E.R.; Das, R.K.; Lemieux, S.K.; Ludwig, E.J.; Thompson, W.J.; Bisenberger, M.; Hertenberger, R.; Hofer, D.; Kader, H.; Schiemenz, P.; Graw, G.; Eiro, A.M.; Santos, F.D.
1992-01-01
Components of α-particle wave functions corresponding to d-d configurations are used to predict analyzing powers in the (d,α) reaction. Tensor analyzing powers, especially A xx , are shown to clearly distinguish between wave functions generated by different realistic nucleon-nucleon interactions. Data for the 58 Ni(d,α) 56 Co reaction to the 7 + stretched-nucleon-orbital state at 2.283-MeV excitation in 56 Co, measured with 22-MeV deuterons, are compared to predictions from the Argonne and Urbana interactions. Similar comparisons are made to data for the lowest J π =7 + state in 48 Sc populated by the 50 Ti(d,α) 48 Sc reaction at 16 MeV
Physical dynamics of quasi-particles in nonlinear wave equations
Energy Technology Data Exchange (ETDEWEB)
Christov, Ivan [Department of Mathematics, Texas A and M University, College Station, TX 77843-3368 (United States)], E-mail: christov@alum.mit.edu; Christov, C.I. [Department of Mathematics, University of Louisiana at Lafayette, Lafayette, LA 70504-1010 (United States)], E-mail: christov@louisiana.edu
2008-02-04
By treating the centers of solitons as point particles and studying their discrete dynamics, we demonstrate a new approach to the quantization of the soliton solutions of the sine-Gordon equation, one of the first model nonlinear field equations. In particular, we show that a linear superposition of the non-interacting shapes of two solitons offers a qualitative (and to a good approximation quantitative) description of the true two-soliton solution, provided that the trajectories of the centers of the superimposed solitons are considered unknown. Via variational calculus, we establish that the dynamics of the quasi-particles obey a pseudo-Newtonian law, which includes cross-mass terms. The successful identification of the governing equations of the (discrete) quasi-particles from the (continuous) field equation shows that the proposed approach provides a basis for the passage from the continuous to a discrete description of the field.
Physical dynamics of quasi-particles in nonlinear wave equations
International Nuclear Information System (INIS)
Christov, Ivan; Christov, C.I.
2008-01-01
By treating the centers of solitons as point particles and studying their discrete dynamics, we demonstrate a new approach to the quantization of the soliton solutions of the sine-Gordon equation, one of the first model nonlinear field equations. In particular, we show that a linear superposition of the non-interacting shapes of two solitons offers a qualitative (and to a good approximation quantitative) description of the true two-soliton solution, provided that the trajectories of the centers of the superimposed solitons are considered unknown. Via variational calculus, we establish that the dynamics of the quasi-particles obey a pseudo-Newtonian law, which includes cross-mass terms. The successful identification of the governing equations of the (discrete) quasi-particles from the (continuous) field equation shows that the proposed approach provides a basis for the passage from the continuous to a discrete description of the field
International Nuclear Information System (INIS)
Lipton, Robert; Polizzi, Anthony
2014-01-01
We employ metamaterial beam-wave interaction structures for tuning the gain and bandwidth of short traveling wave tubes. The interaction structures are made from metal rings of uniform cross section, which are periodically deployed along the length of the traveling wave tube. The aspect ratio of the ring cross sections is adjusted to control both gain and bandwidth. The frequency of operation is controlled by the filling fraction of the ring cross section with respect to the size of the period cell.
International Nuclear Information System (INIS)
Niu, Keishiro; Shimojo, Takashi.
1978-02-01
Increase in kinetic energy of a charged particle, affected by an electrostatic wave propagating perpendicularly to a uniform magnetic field, is obtained for both the initial and later stages. Detrapping time of the particle from the potential dent of the electrostatic wave and energy increase during trapping of the particle is analytically derived. Numerical simulations are carried out to support theoretical results. (auth.)
Charge interaction between particle-laden fluid interfaces.
Xu, Hui; Kirkwood, John; Lask, Mauricio; Fuller, Gerald
2010-03-02
Experiments are described where two oil/water interfaces laden with charged particles move at close proximity relative to one another. The particles on one of the interfaces were observed to be attracted toward the point of closest approach, forming a denser particle monolayer, while the particles on the opposite interface were repelled away from this point, forming a particle depletion zone. Such particle attraction/repulsion was observed even if one of the interfaces was free of particles. This phenomenon can be explained by the electrostatic interaction between the two interfaces, which causes surface charges (charged particles and ions) to redistribute in order to satisfy surface electric equipotential at each interface. In a forced particle oscillation experiment, we demonstrated the control of charged particle positions on the interface by manipulating charge interaction between interfaces.
Novel wave/ion beam interaction approach to isotope separation
International Nuclear Information System (INIS)
Post, R.F.; Lowder, R.S.; Schwager, L.A.; Barr, W.L.; Warner, B.E.
1993-02-01
Numerical simulations and experimental studies have been made related to the possibility of employing an externally imposed electrostatic potential wave to separate isotopes. This wave/ion interaction is a sensitive function of the wave/ion difference velocity and for the appropriate wave amplitude and wave speed, a lighter faster isotope will be reflected by the wave to a higher energy while leaving heavier, slower isotopes virtually undisturbed in energy -- allowing subsequent ion separation by simple energy discrimination. In these experiments, a set of some 200 individual, electrodes, which surrounded a microamp beam of neon ions, was used to generate the wave. Measurements of the wave amplitudes needed for ion reflection and measurements of the final energies of those reflected ions are consistent with values expected from simple kinetic arguments and with the more detailed results of numeric simulations
Quantum walks of two interacting particles on percolation graphs
Siloi, Ilaria; Benedetti, Claudia; Piccinini, Enrico; Paris, Matteo G. A.; Bordone, Paolo
2017-10-01
We address the dynamics of two indistinguishable interacting particles moving on a dynamical percolation graph, i.e., a graph where the edges are independent random telegraph processes whose values jump between 0 and 1, thus mimicking percolation. The interplay between the particle interaction strength, initial state and the percolation rate determine different dynamical regimes for the walkers. We show that, whenever the walkers are initially localised within the interaction range, fast noise enhances the particle spread compared to the noiseless case.
Interactions of Ultracold Impurity Particles with Bose-Einstein Condensates
2015-06-23
AFRL-OSR-VA-TR-2015-0141 INTERACTIONS OF ULTRACOLD IMPURITY PARTICLES WITH BOSE- EINSTEIN CONDENSATES Georg Raithel UNIVERSITY OF MICHIGAN Final...SUBTITLE Interactions of ultracold impurity particles with Bose- Einstein Condensates 5a. CONTRACT NUMBER FA9550-10-1-0453 5b. GRANT NUMBER 5c...Interactions of ultracold impurity particles with Bose- Einstein Condensates Contract/Grant #: FA9550-10-1-0453 Reporting Period: 8/15/2010 to 2/14
Nonlinear mechanisms for drift wave saturation and induced particle transport
International Nuclear Information System (INIS)
Dimits, A.M.; Lee, W.W.
1989-12-01
A detailed theoretical study of the nonlinear dynamics of gyrokinetic particle simulations of electrostatic collisionless and weakly collisional drift waves is presented. In previous studies it was shown that, in the nonlinearly saturated phase of the evolution, the saturation levels and especially the particle fluxes have an unexpected dependence on collisionality. In this paper, the explanations for these collisionality dependences are found to be as follows: The saturation level is determined by a balance between the electron and ion fluxes. The ion flux is small for levels of the potential below an E x B-trapping threshold and increases sharply once this threshold is crossed. Due to the presence of resonant electrons, the electron flux has a much smoother dependence on the potential. In the 2-1/2-dimensional (''pseudo-3D'') geometry, the electrons are accelerated away from the resonance as they diffuse spatially, resulting in an inhibition of their diffusion. Collisions and three-dimensional effects can repopulate the resonance thereby increasing the value of the particle flux. 30 refs., 32 figs., 2 tabs
Slow waves in microchannel metal waveguides and application to particle acceleration
Directory of Open Access Journals (Sweden)
L. C. Steinhauer
2003-06-01
Full Text Available Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO_{2} lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ∼0.6 mm. The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.
Slow waves in microchannel metal waveguides and application to particle acceleration
Steinhauer, L. C.; Kimura, W. D.
2003-06-01
Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO2 lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ˜0.6 mm). The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.
Planckian Interacting Massive Particles as Dark Matter
Garny, Mathias; Sloth, Martin S.
2016-03-10
The Standard Model could be self-consistent up to the Planck scale according to the present measurements of the Higgs mass and top quark Yukawa coupling. It is therefore possible that new physics is only coupled to the Standard Model through Planck suppressed higher dimensional operators. In this case the WIMP miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that dark matter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that dark matter is a Planckian Interacting Massive Particle, we show that the most natural mass larger than $0.01\\,\\textrm{M}_p$ is already ruled out by the absence of tensor modes in the CMB. This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal dark matter model. Finally, we touch upon the KK graviton mode as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar...
Mayr, Hans G.; Mengel, J. G.; Chan, K. L.; Huang, F. T.
2010-01-01
As Lindzen (1981) had shown, small-scale gravity waves (GW) produce the observed reversals of the zonal-mean circulation and temperature variations in the upper mesosphere. The waves also play a major role in modulating and amplifying the diurnal tides (DT) (e.g., Waltersheid, 1981; Fritts and Vincent, 1987; Fritts, 1995a). We summarize here the modeling studies with the mechanistic numerical spectral model (NSM) with Doppler spread parameterization for GW (Hines, 1997a, b), which describes in the middle atmosphere: (a) migrating and non-migrating DT, (b) planetary waves (PW), and (c) global-scale inertio gravity waves. Numerical experiments are discussed that illuminate the influence of GW filtering and nonlinear interactions between DT, PW, and zonal mean variations. Keywords: Theoretical modeling, Middle atmosphere dynamics, Gravity wave interactions, Migrating and non-migrating tides, Planetary waves, Global-scale inertio gravity waves.
Sun, Jicheng; Gao, Xinliang; Lu, Quanming; Chen, Lunjin; Liu, Xu; Wang, Xueyi; Tao, Xin; Wang, Shui
2017-05-01
In this paper, we perform a 1-D particle-in-cell (PIC) simulation model consisting of three species, cold electrons, cold ions, and energetic ion ring, to investigate spectral structures of magnetosonic waves excited by ring distribution protons in the Earth's magnetosphere, and dynamics of charged particles during the excitation of magnetosonic waves. As the wave normal angle decreases, the spectral range of excited magnetosonic waves becomes broader with upper frequency limit extending beyond the lower hybrid resonant frequency, and the discrete spectra tends to merge into a continuous one. This dependence on wave normal angle is consistent with the linear theory. The effects of magnetosonic waves on the background cold plasma populations also vary with wave normal angle. For exactly perpendicular magnetosonic waves (parallel wave number k|| = 0), there is no energization in the parallel direction for both background cold protons and electrons due to the negligible fluctuating electric field component in the parallel direction. In contrast, the perpendicular energization of background plasmas is rather significant, where cold protons follow unmagnetized motion while cold electrons follow drift motion due to wave electric fields. For magnetosonic waves with a finite k||, there exists a nonnegligible parallel fluctuating electric field, leading to a significant and rapid energization in the parallel direction for cold electrons. These cold electrons can also be efficiently energized in the perpendicular direction due to the interaction with the magnetosonic wave fields in the perpendicular direction. However, cold protons can be only heated in the perpendicular direction, which is likely caused by the higher-order resonances with magnetosonic waves. The potential impacts of magnetosonic waves on the energization of the background cold plasmas in the Earth's inner magnetosphere are also discussed in this paper.
Calculation of deuteron wave functions with relativistic interactions
International Nuclear Information System (INIS)
Buck, W.W. III.
1976-01-01
Deuteron wave functions with a repulsive core are obtained numerically from a fully relativistic wave equation introduced by Gross. The numerical technique enables analytic solutions for classes of interactions composed of the relativistic exchanges of a single pion and a single phenomenological meson, sigma. The pion is chosen to interact as a mixture of pseudoscalar and pseudovector. The amount of mixture is determined by a free mixing parameter, lambda, ranging between 1 (pure pseudoscalar) and (pure pseudovector). Each value of lambda corresponds, then, to a different interaction. Solutions are found for lambda = 1, .9, .8, .6, and 0. The wave functions for each interaction come in a group of four. Of the four wave functions, two are the usual S and D state wave functions, while the remaining two, arising out of the relativistic prescription, are identified as 3 P 1 and 1 P 1 wave functions (P state wave functions). For the interactions solved for, the D state probabilities ranged between 5.1 percent and 6.3 percent, while the total P state probabilities ranged between 0.7 percent and 2.7 percent. The method of obtaining solutions was to adjust the sigma meson parameters to give the correct binding energy and a good quadrupole moment. All wave functions obtained are applied to relativistic N-d scattering in the backward direction where the effect of the P states is quite measurable
Interaction of electromagnetic waves with plasma in the radiation-dominated regime
International Nuclear Information System (INIS)
Bulanov, S.V.; Esirkepov, T.Zh.; Koga, J.; Tajima, T.
2004-01-01
A study is made of the main regimes of interaction of relativistically strong electromagnetic waves with plasma under conditions in which the radiation from particles plays a dominant role. The discussion is focused on such issues as the generation of short electromagnetic pulses in the interaction of laser light with clusters and highly efficient ion acceleration in a thin plasma slab under the action of the ponderomotive pressure of the wave. An approach is developed for generating superintense electromagnetic pulses by means of up-to-date laser devices
Blackwell, William C., Jr.
2004-01-01
In this paper space is modeled as a lattice of Compton wave oscillators (CWOs) of near- Planck size. It is shown that gravitation and special relativity emerge from the interaction between particles Compton waves. To develop this CWO model an algorithmic approach was taken, incorporating simple rules of interaction at the Planck-scale developed using well known physical laws. This technique naturally leads to Newton s law of gravitation and a new form of doubly special relativity. The model is in apparent agreement with the holographic principle, and it predicts a cutoff energy for ultrahigh-energy cosmic rays that is consistent with observational data.
Catastrophes in the interaction of light waves in anisotropic resonator
International Nuclear Information System (INIS)
Mkrtchyan, A.R.; Nersisyan, S.R.; Tabiryan, N.V.
1993-01-01
An origin of jump-like and hysteresical phenomena is predicted theoretically. Those are caused by the ruling of the state of non-linear anisotropic resonator with an orthogonal polarization of light waves. The resonator creates a turned connection as well as causes a complex tying between the waves. The later conditions a whole number of the interacting waves regimes because of a big number of ruling parameters. 5 refs
Experimental particle acceleration by water evaporation induced by shock waves
Scolamacchia, T.; Alatorre Ibarguengoitia, M.; Scheu, B.; Dingwell, D. B.; Cimarelli, C.
2010-12-01
Shock waves are commonly generated during volcanic eruptions. They induce sudden changes in pressure and temperature causing phase changes. Nevertheless, their effects on flowfield properties are not well understood. Here we investigate the role of gas expansion generated by shock wave propagation in the acceleration of ash particles. We used a shock tube facility consisting of a high-pressure (HP) steel autoclave (450 mm long, 28 mm in internal diameter), pressurized with Ar gas, and a low-pressure tank at atmospheric conditions (LP). A copper diaphragm separated the HP autoclave from a 180 mm tube (PVC or acrylic glass) at ambient P, with the same internal diameter of the HP reservoir. Around the tube, a 30 cm-high acrylic glass cylinder, with the same section of the LP tank (40 cm), allowed the observation of the processes occurring downstream from the nozzle throat, and was large enough to act as an unconfined volume in which the initial diffracting shock and gas jet expand. All experiments were performed at Pres/Pamb ratios of 150:1. Two ambient conditions were used: dry air and air saturated with steam. Carbon fibers and glass spheres in a size range between 150 and 210 μm, were placed on a metal wire at the exit of the PVC tube. The sudden decompression of the Ar gas, due to the failure of the diaphragm, generated an initial air shock wave. A high-speed camera recorded the processes between the first 100 μsec and several ms after the diaphragm failure at frame rates ranging between 30,000 and 50,000 fps. In the experiments with ambient air saturated with steam, the high-speed camera allowed to visualize the condensation front associated with the initial air shock; a maximum velocity of 788 m/s was recorded, which decreases to 524 m/s at distance of 0.5 ±0.2 cm, 1.1 ms after the diaphragm rupture. The condensation front preceded the Ar jet front exhausting from the reservoir, by 0.2-0.5 ms. In all experiments particles velocities following the initial
Interaction of gravitational waves with superconductors
Energy Technology Data Exchange (ETDEWEB)
Inan, N.A.; Thompson, J.J. [University of California, Schools of Natural Sciences, Merced, CA (United States); Chiao, R.Y. [University of California, Schools of Natural Sciences and Engineering, Merced, CA (United States)
2017-06-15
Applying the Helmholtz Decomposition theorem to linearized General Relativity leads to a gauge-invariant formulation where the transverse-traceless part of the metric perturbation describes gravitational waves in matter. Gravitational waves incident on a superconductor can be described by a linear London-like constituent equation characterized by a ''gravitational shear modulus'' and a corresponding plasma frequency and penetration depth. Electric-like and magnetic-like gravitational tensor fields are defined in terms of the strain field of a gravitational wave. It is shown that in the DC limit, the magnetic-like tensor field is expelled from the superconductor in a gravitational Meissner-like effect. The Cooper pair density is described by the Ginzburg-Landau theory embedded in curved space-time. The ionic lattice is modeled by quantum harmonic oscillators coupled to gravitational waves and characterized by quasi-energy eigenvalues for the phonon modes. The formulation predicts the possibility of a dynamical Casimir effect since the zero-point energy of the ionic lattice phonons is found to be modulated by the gravitational wave, in a quantum analog of a ''Weber-bar effect.'' Applying periodic thermodynamics and the Debye model in the low-temperature limit leads to a free energy density for the ionic lattice. Lastly, we relate the gravitational strain of space to the strain of matter to show that the response to a gravitational wave is far less for the Cooper pair density than for the ionic lattice. This predicts a charge separation effect in the superconductor as a result of the gravitational wave. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Interaction of Energetic Particles with Discontinuities Upstream of Strong Shocks
Malkov, Mikhail; Diamond, Patrick
2008-11-01
Acceleration of particles in strong astrophysical shocks is known to be accompanied and promoted by a number of instabilities which are driven by the particles themselves. One of them is an acoustic (also known as Drury's) instability driven by the pressure gradient of accelerated particles upstream. The generated sound waves naturally steepen into shocks thus forming a shocktrain. Similar magnetoacoustic or Alfven type structures may be driven by pick-up ions, for example. We consider the solutions of kinetic equation for accelerated particles within the shocktrain. The accelerated particles are assumed to be coupled to the flow by an intensive pitch-angle scattering on the self-generated Alfven waves. The implications for acceleration and confinement of cosmic rays in this shock environment will be discussed.
International Nuclear Information System (INIS)
Omura, Yoshiharu; Matsumoto, Hiroshi.
1989-01-01
Past theoretical and numerical studies of the nonlinear evolution of electromagnetic cyclotron waves are reviewed. Such waves are commonly observed in space plasmas such as Alfven waves in the solar wind or VLF whistler mode waves in the magnetosphere. The use of an electromagnetic full-particle code to study an electron cyclotron wave and of an electromagnetic hybrid code to study an ion cyclotron wave is demonstrated. Recent achievements in the simulations of nonlinear revolution of electromagnetic cyclotron waves are discussed. The inverse cascading processes of finite-amplitude whistler and Alfven waves is interpreted in terms of physical elementary processes. 65 refs
Turbulent spectra from three drift-wave interactions
International Nuclear Information System (INIS)
Terry, P.W.; Horton, W.
1982-02-01
Hydrodynamic equations for the drift-wave instability containing the rvec E x rvec B convective nonlinearity are used to show that the three wave interactions lead to temporal chaos with broad-band frequency spectra in the saturated state. 7 refs., 2 figs
Transonic shock wave. Boundary layer interaction at a convex wall
Koren, B.; Bannink, W.J.
1984-01-01
A standard finite element procedure has been applied to the problem of transonic shock wave – boundary layer interaction at a convex wall. The method is based on the analytical Bohning-Zierep model, where the boundary layer is perturbed by a weak normal shock wave which shows a singular pressure
An interacting particle process related to Young tableaux
Borodin, Alexei; Olshanski, Grigori
2013-01-01
We discuss a stochastic particle system consisting of a two-dimensional array of particles living in one space dimension. The stochastic evolution bears a certain similarity to Hammersley's process, and the particle interaction is governed by combinatorics of the Young tableaux.
Elementary particles and basic interactions. Trends and perspectives
International Nuclear Information System (INIS)
Baton, J.P.; Cohen-Tannoudji, G.
1992-06-01
This lesson given to Physics teachers, takes stock of actual knowledge and trends in Particle Physics: basic interactions and unification, elementary particles (lepton-quarks), fields theories, boson and gluon discovery. It reminds the operating principle of different large accelerators established in the world and associated particle detectors. It includes also a glossary
Ground-satellite study of wave-particle correlations
International Nuclear Information System (INIS)
Park, C.G.; Lin, C.S.; Parks, G.K.
1981-01-01
Very low frequency (VLF) waves recorded at Siple, Antarctica (Lapprox.4; 84 0 W, geographic), are compared with low-energy ( 0 W, near the outer edge of the nominal ''viewing area'' of the Siple VLF receiver, which is estimated to be Lapprox.2-6 and +- 20 0 longitude. The results reveal two distinct types of chorus observed at Siple. One type is closely correlated with enhanced fluxes of >5-keV electrons detected at the synchronous altitude, and its generation region is inferred to be outside the plasmapause. The chorus upper cutoff frequency increases with time in a characteristic manner, consistent with the expected adiabatic motion of injected electrons in cyclotron resonance with the waves. The second type of chorus, which we refer to as ''plasmaspheric chorus,'' occurs inside the plasmapause, has no apparent relationship to particle injection at the synchronous altitude and shows clear evidence of being triggered by whistlers, power line radiation, and other signals. The two different types of chorus are readily distinguishable in frequency-time spectrograms
Experimental investigation of gravity wave turbulence and of non-linear four wave interactions..
Berhanu, Michael
2017-04-01
Using the large basins of the Ecole Centrale de Nantes (France), non-linear interactions of gravity surface waves are experimentally investigated. In a first part we study statistical properties of a random wave field regarding the insights from the Wave Turbulence Theory. In particular freely decaying gravity wave turbulence is generated in a closed basin. No self-similar decay of the spectrum is observed, whereas its Fourier modes decay first as a time power law due to nonl-inear mechanisms, and then exponentially due to linear viscous damping. We estimate the linear, non-linear and dissipative time scales to test the time scale separation. By estimation of the mean energy flux from the initial decay of wave energy, the Kolmogorov-Zakharov constant of the weak turbulence theory is evaluated. In a second part, resonant interactions of oblique surface gravity waves in a large basin are studied. We generate two oblique waves crossing at an acute angle. These mother waves mutually interact and give birth to a resonant wave whose properties (growth rate, resonant response curve and phase locking) are fully characterized. All our experimental results are found in good quantitative agreement with four-wave interaction theory. L. Deike, B. Miquel, P. Gutiérrez, T. Jamin, B. Semin, M. Berhanu, E. Falcon and F. Bonnefoy, Role of the basin boundary conditions in gravity wave turbulence, Journal of Fluid Mechanics 781, 196 (2015) F. Bonnefoy, F. Haudin, G. Michel, B. Semin, T. Humbert, S. Aumaître, M. Berhanu and E. Falcon, Observation of resonant interactions among surface gravity waves, Journal of Fluid Mechanics (Rapids) 805, R3 (2016)
Interactions of solitary waves and compression/expansion waves in core-annular flows
Maiden, Michelle; Anderson, Dalton; El, Gennady; Franco, Nevil; Hoefer, Mark
2017-11-01
The nonlinear hydrodynamics of an initial step leads to the formation of rarefaction waves and dispersive shock waves in dispersive media. Another hallmark of these media is the soliton, a localized traveling wave whose speed is amplitude dependent. Although compression/expansion waves and solitons have been well-studied individually, there has been no mathematical description of their interaction. In this talk, the interaction of solitons and shock/rarefaction waves for interfacial waves in viscous, miscible core-annular flows are modeled mathematically and explored experimentally. If the interior fluid is continuously injected, a deformable conduit forms whose interfacial dynamics are well-described by a scalar, dispersive nonlinear partial differential equation. The main focus is on interactions of solitons with dispersive shock waves and rarefaction waves. Theory predicts that a soliton can either be transmitted through or trapped by the extended hydrodynamic state. The notion of reciprocity is introduced whereby a soliton interacts with a shock wave in a reciprocal or dual fashion as with the rarefaction. Soliton reciprocity, trapping, and transmission are observed experimentally and are found to agree with the modulation theory and numerical simulations. This work was partially supported by NSF CAREER DMS-1255422 (M.A.H.) and NSF GRFP (M.D.M.).
Interaction of EM Waves with Atmospheric Pressure Plasmas
National Research Council Canada - National Science Library
Laroussi, Mounir
2000-01-01
.... The focus of the main activities is the generation of large volume, non-thermal, atmospheric pressure plasmas, their diagnostics, and their interactions with EM waves and with the cells of microorganism...
Quantum theory of nonrelativistic particles interacting with gravity
International Nuclear Information System (INIS)
Anastopoulos, C.
1996-01-01
We investigate the effects of the gravitational field on the quantum dynamics of nonrelativistic particles. We consider N nonrelativistic particles, interacting with the linearized gravitational field. Using the Feynman-Vernon influence functional technique, we trace out the graviton field to obtain a master equation for the system of particles to first order in G. The effective interaction between the particles as well as the self-interaction is in general non-Markovian. We show that the gravitational self-interaction cannot be held responsible for decoherence of microscopic particles due to the fast vanishing of the diffusion function. For macroscopic particles though, it leads to diagonalization to the energy eigenstate basis, a desirable feature in gravity-induced collapse models. We finally comment on possible applications. copyright 1996 The American Physical Society
Directory of Open Access Journals (Sweden)
Mihai V. Putz
2010-10-01
Full Text Available Within the path integral Feynman formulation of quantum mechanics, the fundamental Heisenberg Uncertainty Relationship (HUR is analyzed in terms of the quantum fluctuation influence on coordinate and momentum estimations. While introducing specific particle and wave representations, as well as their ratio, in quantifying the wave-to-particle quantum information, the basic HUR is recovered in a close analytical manner for a large range of observable particle-wave Copenhagen duality, although with the dominant wave manifestation, while registering its progressive modification with the factor √1-n2, in terms of magnitude n ε [0,1] of the quantum fluctuation, for the free quantum evolution around the exact wave-particle equivalence. The practical implications of the present particle-to-wave ratio as well as of the free-evolution quantum picture are discussed for experimental implementation, broken symmetry and the electronic localization function.
Keilbach, D.; Drews, C.; Berger, L.; Marsch, E.; Wimmer-Schweingruber, R. F.
2017-12-01
Using a test particle approach we have investigated, how an oxygen pickup ion torus velocity distribution is modified by continuous and intermittent alfvènic waves on timescales, where the gyro trajectory of each particle can be traced.We have therefore exposed the test particles to mono frequent waves, which expanded through the whole simulation in time and space. The general behavior of the pitch angle distribution is found to be stationary and a nonlinear function of the wave frequency, amplitude and the initial angle between wave elongation and field-perpendicular particle velocity vector. The figure shows the time-averaged pitch angle distributions as a function of the Doppler shifted wave frequency (where the Doppler shift was calculated with respect to the particles initial velocity) for three different wave amplitudes (labeled in each panel). The background field is chosen to be 5 nT and the 500 test particles were initially distributed on a torus with 120° pitch angle at a solar wind velocity of 450 km/s. Each y-slice of the histogram (which has been normalized to it's respective maximum) represents an individual run of the simulation.The frequency-dependent behavior of the test particles is found to be classifiable into the regimes of very low/high frequencies and frequencies close to first order resonance. We have found, that only in the latter regime the particles interact strongly with the wave, where in the time averaged histograms a branch structure is found, which was identified as a trace of particles co-moving with the wave phase. The magnitude of pitch angle change of these particles is as well as the frequency margin, where the branch structure is found, an increasing function with the wave amplitude.We have also investigated the interaction with mono frequent intermittent waves. Exposed to such waves a torus distribution is scattered in pitch angle space, whereas the pitch angle distribution is broadened systematically over time similar to
Interaction of free charged particles with a chirped electromagnetic pulse
Khachatryan, A.G.; van Goor, F.A.; Boller, Klaus J.
2004-01-01
We study the effect of chirp on electromagnetic (EM) pulse interaction with a charged particle. Both the one-dimensional (1D) and 3D cases are considered. It is found that, in contrast to the case of a nonchirped pulse, the charged particle energy can be changed after the interaction with a 1D EM
Elementary Particle Interactions with CMS at LHC
International Nuclear Information System (INIS)
Spanier, Stefan
2016-01-01
The High Energy Particle Physics group of the University of Tennessee participates in the search for new particles and forces in proton-proton collisions at the LHC with the Compact Muon Solenoid experiment. Since the discovery of the Higgs boson in 2012, the search has intensified to find new generations of particles beyond the standard model using the higher collision energies and ever increasing luminosity, either directly or via deviations from standard model predictions such as the Higgs boson decays. As part of this effort, the UTK group has expanded the search for new particles in four-muon final states, and in final states with jets, has successfully helped and continues to help to implement and operate an instrument for improved measurements of the luminosity needed for all data analyses, and has continued to conduct research of new technologies for charged particle tracking at a high-luminosity LHC.
Elementary Particle Interactions with CMS at LHC
Energy Technology Data Exchange (ETDEWEB)
Spanier, Stefan [Univ. of Tennessee, Knoxville, TN (United States)
2016-07-31
The High Energy Particle Physics group of the University of Tennessee participates in the search for new particles and forces in proton-proton collisions at the LHC with the Compact Muon Solenoid experiment. Since the discovery of the Higgs boson in 2012, the search has intensified to find new generations of particles beyond the standard model using the higher collision energies and ever increasing luminosity, either directly or via deviations from standard model predictions such as the Higgs boson decays. As part of this effort, the UTK group has expanded the search for new particles in four-muon final states, and in final states with jets, has successfully helped and continues to help to implement and operate an instrument for improved measurements of the luminosity needed for all data analyses, and has continued to conduct research of new technologies for charged particle tracking at a high-luminosity LHC.
Artemyev, A V; Neishtadt, A I; Zelenyi, L M; Vainchtein, D L
2010-12-01
We present an analytical and numerical study of the surfatron acceleration of nonrelativistic charged particles by electromagnetic waves. The acceleration is caused by capture of particles into resonance with one of the waves. We investigate capture for systems with one or two waves and provide conditions under which the obtained results can be applied to systems with more than two waves. In the case of a single wave, the once captured particles never leave the resonance and their velocity grows linearly with time. However, if there are two waves in the system, the upper bound of the energy gain may exist and we find the analytical value of that bound. We discuss several generalizations including the relativistic limit, different wave amplitudes, and a wide range of the waves' wavenumbers. The obtained results are used for qualitative description of some phenomena observed in the Earth's magnetosphere. © 2010 American Institute of Physics.
On the interaction between ocean surface waves and seamounts
Sosa, Jeison; Cavaleri, Luigi; Portilla-Yandún, Jesús
2017-12-01
Of the many topographic features, more specifically seamounts, that are ubiquitous in the ocean floor, we focus our attention on those with relatively shallow summits that can interact with wind-generated surface waves. Among these, especially relatively long waves crossing the oceans (swells) and stormy seas are able to affect the water column up to a considerable depth and therefore interact with these deep-sea features. We quantify this interaction through numerical experiments using a numerical wave model (SWAN), in which a simply shaped seamount is exposed to waves of different length. The results show a strong interaction that leads to significant changes in the wave field, creating wake zones and regions of large wave amplification. This is then exemplified in a practical case where we analyze the interaction of more realistic sea conditions with a very shallow rock in the Yellow Sea. Potentially important for navigation and erosion processes, mutatis mutandis, these results are also indicative of possible interactions with emerged islands and sand banks in shelf seas.
Waves and fluid-solid interaction in stented blood vessels
Frecentese, S.; Argani, L. P.; Movchan, A. B.; Movchan, N. V.; Carta, G.; Wall, M. L.
2018-01-01
This paper focuses on the modelling of fluid-structure interaction and wave propagation problems in a stented artery. Reflection of waves in blood vessels is well documented in the literature, but it has always been linked to a strong variation in geometry, such as the branching of vessels. The aim of this work is to detect the possibility of wave reflection in a stented artery due to the repetitive pattern of the stents. The investigation of wave propagation and possible blockages under time-harmonic conditions is complemented with numerical simulations in the transient regime.
Gas-liquid transition in the model of particles interacting at high energy
International Nuclear Information System (INIS)
Bondarenko, S.; Komoshvili, K.
2013-01-01
An application of the ideas of the inertial confinement fusion process in the case of particles interacting at high energy is investigated. A possibility of the gas-liquid transition in the gas is considered using different approaches. In particular, a shock wave description of interactions between particles is studied and a self-similar solution of Euler's equation is discussed. Additionally, the Boltzmann equation is solved for a self-consistent field (Vlasov's equation) in the linear approximation for the case of a gas under external pressure and the corresponding change of the Knudsen number of the system is calculated. (orig.)
Energy exchange in systems of particles with nonreciprocal interaction
Energy Technology Data Exchange (ETDEWEB)
Vaulina, O. S.; Lisina, I. I., E-mail: Irina.Lisina@mail.ru; Lisin, E. A. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)
2015-10-15
A model is proposed to describe the sources of additional kinetic energy and its redistribution in systems of particles with a nonreciprocal interaction. The proposed model is shown to explain the qualitative specific features of the dust particle dynamics in the sheath region of an RF discharge. Prominence is given to the systems of particles with a quasi-dipole–dipole interaction, which is similar to the interaction induced by the ion focusing effects that occur in experiments on a laboratory dusty plasma, and with the shadow interaction caused by thermophoretic forces and Le Sage’s forces.
Elasto-capillary interactions of drops and particles
Snoeijer, Jacco; Pandey, Anupam; Karpitschka, Stefan; Nawijn, Charlotte; Botto, Lorenzo; Andreotti, Bruno
2017-11-01
The interaction of solid particles floating on a liquid interface is popularly known as the Cheerios effect. Here we present similar interactions for particles and droplets on elastic surfaces, mediated by elastic deformation. We start with the Inverted Cheerios effect, by considering liquid drops on a solid gel. Remarkably, the interaction can be tuned from attractive to repulsive, as shown experimentally and theoretically. We then turn to more general cases of particles on elastic layers, for which new interaction laws are derived. An overview is given on the various regimes, including the crossover from purely elastic to purely capillary interfaces. ERC Consolidator Grant 616918.
Umeyama, Motohiko
2012-04-13
This paper investigates the velocity and the trajectory of water particles under surface waves, which propagate at a constant water depth, using particle image velocimetry (PIV). The vector fields and vertical distributions of velocities are presented at several phases in one wave cycle. The third-order Stokes wave theory was employed to express the physical quantities. The PIV technique's ability to measure both temporal and spatial variations of the velocity was proved after a series of attempts. This technique was applied to the prediction of particle trajectory in an Eulerian scheme. Furthermore, the measured particle path was compared with the positions found theoretically by integrating the Eulerian velocity to the higher order of a Taylor series expansion. The profile of average travelling distance is also presented with a solution of zero net mass flux in a closed wave flume.
Modelling and simulation of particle-particle interaction in a magnetophoretic bio-separation chip
Alam, Manjurul; Golozar, Matin; Darabi, Jeff
2018-04-01
A Lagrangian particle trajectory model is developed to predict the interaction between cell-bead particle complexes and to track their trajectories in a magnetophoretic bio-separation chip. Magnetic flux gradients are simulated in the OpenFOAM CFD software and imported into MATLAB to obtain the trapping lengths and trajectories of the particles. A connector vector is introduced to calculate the interaction force between cell-bead complexes as they flow through a microfluidic device. The interaction force calculations are performed for cases where the connector vector is parallel, perpendicular, and at an angle of 45° with the applied magnetic field. The trajectories of the particles are simulated by solving a system of eight ordinary differential equations using a fourth order Runge-Kutta method. The model is then used to study the effects of geometric positions and angles of the connector vector between the particles as well as the cell size, number of beads per cell, and flow rate on the interaction force and trajectories of the particles. The results show that the interaction forces may be attractive or repulsive, depending on the orientation of the connector vector distance between the particle complexes and the applied magnetic field. When the interaction force is attractive, the particles are observed to merge and trap sooner than a single particle, whereas a repulsive interaction force has little or no effect on the trapping length.
2015-09-30
Interaction of Surface Gravity Waves with Nonlinear Internal Gravity Waves Lian Shen St. Anthony Falls Laboratory and Department of Mechanical...on studying surface gravity wave evolution and spectrum in the presence of surface currents caused by strongly nonlinear internal solitary waves...interaction of surface and internal gravity waves in the South China Sea. We will seek answers to the following questions: 1) How does the wind-wave
Sotnikov, V.; Kim, T.; Caplinger, J.; Main, D.; Mishin, E.; Gershenzon, N.; Genoni, T.; Paraschiv, I.; Rose, D.
2018-04-01
The concept of a parametric antenna in ionospheric plasma is analyzed. Such antennas are capable of exciting electromagnetic radiation fields, specifically the creation of whistler waves generated at the very low frequency (VLF) range, which are also capable of propagating large distances away from the source region. The mechanism of whistler wave generation is considered a parametric interaction of quasi-electrostatic whistler waves (also known as low oblique resonance (LOR) oscillations) excited by a conventional loop antenna. The interaction of LOR waves with quasi-neutral density perturbations in the near field of an antenna gives rise to electromagnetic whistler waves on combination frequencies. It is shown in this work that the amplitude of these waves can considerably exceed the amplitude of whistler waves directly excited by a loop. Additionally, particle-in-cell simulations, which demonstrate the excitation and spatial structure of VLF waves excited by a loop antenna, are presented. Possible applications including the wave-particle interactions to mitigate performance anomalies of low Earth orbit satellites, active space experiments, communication via VLF waves, and modification experiments in the ionosphere will be discussed.
Mean multiplicity of secondary particles in hadron-nuclear interactions
International Nuclear Information System (INIS)
Alaverdyan, G.B.; Pak, A.S.
1980-01-01
The mean multiplicity of secondary particles in hA interactions is examined in the framework of the multiplex scattering theory. The dependence of the secondary particle multiplicity coefficient Rsub(6)=anti nsub(hA)/anti nsub(hN) (where anti nsub(hA) and anti nsub(hN) are mean multiplicities of secondary relativistic particles in hA and hN interactions, respectively) on the energy and type of incident particles and atomic number of a target nucleus is analysed. It is shown that predictions of the leading particle cascade model are in satisfactory agreement with the experimental data if the uncertainties of the inelasticity in hN interactions are taken into account. The value Rsub(A) weakly depends both on the incident particle energy and the form of parametrization anti nsub(hN)(E). Allowance of energy losses fluctuation of leading particle results in the Rsub(A) value decrease. From the model of leading particles it does not follow that Rsub(a) strictly depends on the type of incident particles at the fixed value of mean number of collisions. But quantitative values of Rsub(A) for different types of particles and at one value of anti ν, (i.e. at properly chosen value) coincide. The value of Rsub(A) is profoundly dependent on the values of inelasticity factor in hN interactions
Nonlinear interaction of energetic ring current protons with magnetospheric hydromagnetic waves
International Nuclear Information System (INIS)
Chan, A.A.; Chen, L.; White, R.B.
1989-01-01
In order to study nonlinear wave-particle interactions in the Earth's magnetosphere we have derived Hamiltonian equations for the gyrophase-averaged nonrelativistic motion of charged particles in a perturbed dipole magnetic field. We assume low frequency (less than the proton gyrofrequency) fully electromagnetic perturbations, and we retain finite Larmor radius effects. Analytic and numerical results for the stochastic threshold of energetic protons (approx-gt 100 keV) in compressional geomagnetic pulsations in the Pc 5 range of frequencies 150--600 seconds are presented. These protons undergo a drift-bounce resonance with the Pc 5 waves which breaks the second (longitudinal) and third (flux) adiabatic invariants, while the first invariant (the magnetic moment) and the proton energy are approximately conserved. The proton motion in the observed spectrum of waves is found to be strongly diffusive, due to the overlap of neighboring primary resonances. copyright American Geophysical Union 1989
Nonlinear interaction of energetic ring current protons with magnetospheric hydromagnetic waves
International Nuclear Information System (INIS)
Chan, A.A.; Chen, Liu; White, R.B.
1989-09-01
In order to study nonlinear wave-particle interactions in the earth's magnetosphere we have derived Hamiltonian equations for the gyrophase-averaged nonrealistic motion of charged particles in a perturbed dipole magnetic field. We assume low frequency (less than the proton gyrofrequency) fully electromagnetic perturbations, and we retain finite Larmor radius effects. Analytic and numerical results for the stochastic threshold of energetic protons (approx gt 100 keV) in compressional geomagnetic pulsations in the Pc 5 range of frequencies (150--600 seconds) are presented. These protons undergo a drift-bounce resonance with the Pc 5 waves which breaks the second (longitudinal) and third (flux) adiabatic invariants, while the first invariant (the magnetic moment) and the proton energy are approximately conserved. The proton motion in the observed spectrum of waves is found to be strongly diffusive, due to the overlap of neighboring primary resonances. 17 refs., 2 figs
Experimental comparison of particle interaction measurement techniques using optical traps
International Nuclear Information System (INIS)
Koehler, Timothy P.; Grillet, Anne Mary; Brotherton, Christopher M.; Molecke, Ryan A.
2008-01-01
Optical tweezers has become a powerful and common tool for sensitive determination of electrostatic interactions between colloidal particles. Recently, two techniques, 'blinking' tweezers and direct force measurements, have become increasingly prevalent in investigations of inter-particle potentials. The 'blinking' tweezers method acquires physical statistics of particle trajectories to determine drift velocities, diffusion coefficients, and ultimately colloidal forces as a function of the center-center separation of two particles. Direct force measurements monitor the position of a particle relative to the center of an optical trap as the separation distance between two continuously trapped particles is gradually decreased. As the particles near each other, the displacement from the trap center for each particle increases proportional to the inter-particle force. Although commonly employed in the investigation of interactions of colloidal particles, there exists no direct comparison of these experimental methods in the literature. In this study, an experimental apparatus was developed capable of performing both methods and is used to quantify electrostatic potentials between particles in several particle/solvent systems. Comparisons are drawn between the experiments conducted using the two measurement techniques, theory, and existing literature. Forces are quantified on the femto-Newton scale and results agree well with literature values
Waves reflected by solid wall and wave interaction in vapour bubbly liquids
International Nuclear Information System (INIS)
Duong, N.H.; Nguyen, V.T.
2004-01-01
The vapour bubbly liquids are met in many natural and industrial processes, including in energy equipment. In the nuclear power plants this kind of medium appears in reactor cores (PWR, BWR and etc.), in turbine generators and in heat transfer loops. Due to some circumstances (for example, a hit caused by detonations or strong collisions) the pressure waves can appear in the bubbly liquid medium contained in those facilities. These waves propagate in the mixtures and interact with themselves and with structures. It is important that what will occur during mentioned above processes. The knowledge of this kind processes will be useful for analysing the different sorts of the processes occurred in the energy facilities where the vapor bubbly liquids are used as working or heat transfer medium, like nuclear power plants, and also useful in finding the measures for prevention of unfavourable phenomena (for example, during wave interactions maybe appear too high pressures, which could lead into damages of facilities and etc.) and safety operating the equipment. From the physical point of view, the waves in this kind of medium are interesting that owing to non-linear, dispersion and dissipation effects the wave patterns in them may be diverse and easy altered. In the paper the investigation results of the waves reflected by solid wall or structure of the moderate intensity shock waves, and the behaviour of pressure in the process of wave interaction in some mixtures of liquid with vapour bubbles (of radium ∼1 mm) are presented. (author)
On slow particle production in hadron-nucleus interactions
International Nuclear Information System (INIS)
Stenlund, E.; Otterlund, I.
1982-01-01
A model for slow particle production in hadron-nucleus interactions is presented. The model succesfully predicts correlations between the number of knock-on particles and the number of particles associated with the evaporation process as well as correlations with the number of collisions, ν, between the incident hadron and the nucleons inside the target nucleus. The model provides two independent possibilities to determine the number of primary intranuclear collisions, ν, i.e. by its correlation to the number of knock-on particles or to the number of evaporated particles. The good agreement indicates that the model gives an impact-parameter sensitive description of hardron nucleus reactions. (orig.)
Interaction of free charged particles with a chirped electromagnetic pulse
International Nuclear Information System (INIS)
Khachatryan, A.G.; Goor, F.A. van; Boller, K.-J.
2004-01-01
We study the effect of chirp on electromagnetic (EM) pulse interaction with a charged particle. Both the one-dimensional (1D) and 3D cases are considered. It is found that, in contrast to the case of a nonchirped pulse, the charged particle energy can be changed after the interaction with a 1D EM chirped pulse. Different types of chirp and pulse envelopes are considered. In the case of small chirp, an analytical expression is found for arbitrary temporal profiles of the chirp and the pulse envelope. In the 3D case, the interaction with a chirped pulse results in a polarization-dependent scattering of charged particles
Planetary wave-gravity wave interactions during mesospheric inversion layer events
Ramesh, K.; Sridharan, S.; Raghunath, K.; Vijaya Bhaskara Rao, S.; Bhavani Kumar, Y.
2013-07-01
amplitude may get modulated by the interaction between gravity waves and planetary waves. The eddy diffusion associated with gravity wave drag may also cause suppression in the planetary wave activity.
Acoustic tweezing of particles using decaying opposing travelling surface acoustic waves (DOTSAW).
Ng, Jia Wei; Devendran, Citsabehsan; Neild, Adrian
2017-10-11
Surface acoustic waves offer a versatile and biocompatible method of manipulating the location of suspended particles or cells within microfluidic systems. The most common approach uses the interference of identical frequency, counter propagating travelling waves to generate a standing surface acoustic wave, in which particles migrate a distance less than half the acoustic wavelength to their nearest pressure node. The result is the formation of a periodic pattern of particles. Subsequent displacement of this pattern, the prerequisite for tweezing, can be achieved by translation of the standing wave, and with it the pressure nodes; this requires changing either the frequency of the pair of waves, or their relative phase. Here, in contrast, we examine the use of two counterpropagating traveling waves of different frequency. The non-linearity of the acoustic forces used to manipulate particles, means that a small frequency difference between the two waves creates a substantially different force field, which offers significant advantages. Firstly, this approach creates a much longer range force field, in which migration takes place across multiple wavelengths, and causes particles to be gathered together in a single trapping site. Secondly, the location of this single trapping site can be controlled by the relative amplitude of the two waves, requiring simply an attenuation of one of the electrical drive signals. Using this approach, we show that by controlling the powers of the opposing incoherent waves, 5 μm particles can be migrated laterally across a fluid flow to defined locations with an accuracy of ±10 μm.
Slow wave structures using twisted waveguides for charged particle applications
Kang, Yoon W.; Fathy, Aly E.; Wilson, Joshua L.
2012-12-11
A rapidly twisted electromagnetic accelerating structure includes a waveguide body having a central axis, one or more helical channels defined by the body and disposed around a substantially linear central axial channel, with central portions of the helical channels merging with the linear central axial channel. The structure propagates electromagnetic waves in the helical channels which support particle beam acceleration in the central axial channel at a phase velocity equal to or slower than the speed of light in free space. Since there is no variation in the shape of the transversal cross-section along the axis of the structure, inexpensive mechanical fabrication processes can be used to form the structure, such as extrusion, casting or injection molding. Also, because the field and frequency of the resonant mode depend on the whole structure rather than on dimensional tolerances of individual cells, no tuning of individual cells is needed. Accordingly, the overall operating frequency may be varied with a tuning/phase shifting device located outside the resonant waveguide structure.
International Nuclear Information System (INIS)
Erokhin, N.S.; Zol'nikova, N.N.; Mikhajlovskaya, L.A.
1991-01-01
Relativistic acceleration of charged particles, captured by a longitudinal wave in a slightly inhomogeneous plasma without an external magnetic field is considered numerically and analytically. It is shown that with the growth of the plasma inhomogeneity parameter the maximum energy of accelerated captured particles exponentially increases. Attention is paid to the possibility of 'eternal' confinement and, respectively, unlimited acceleration of captured particles by an undamped longitudinal wave in a plasma without a magnetic field
VIGOR: Virtual Interaction with Gravitational Waves to Observe Relativity
Kitagawa, Midori; Kesden, Michael; Tranm, Ngoc; Venlayudam, Thulasi Sivampillai; Urquhart, Mary; Malina, Roger
2017-05-01
In 2015, a century after Albert Einstein published his theory of general relativity, the Laser Interferometer Gravitational-wave Observatory (LIGO) detected gravitational waves from binary black holes fully consistent with this theory. Our goal for VIGOR (Virtual-reality Interaction with Gravitational waves to Observe Relativity) is to communicate this revolutionary discovery to the public by visualizing the gravitational waves emitted by binary black holes. VIGOR has been developed using the Unity game engine and VR headsets (Oculus Rift DK2 and Samsung Gear VR). Wearing a VR headset, VIGOR users control an avatar to "fly" around binary black holes, experiment on the black holes by manipulating their total mass, mass ratio, and orbital separation, and witness how gravitational waves emitted by the black holes stretch and squeeze the avatar. We evaluated our prototype of VIGOR with high school students in 2016 and are further improving VIGOR based on our findings.
Directory of Open Access Journals (Sweden)
Qing Zhang
2018-01-01
Full Text Available Electric force is the most popular technique for bioparticle transportation and manipulation in microfluidic systems. In this paper, the iterative dipole moment (IDM method was used to calculate the dielectrophoretic (DEP forces of particle-particle interactions in a two-dimensional DC electric field, and the Lagrangian method was used to solve the transportation of particles. It was found that the DEP properties and whether the connection line between initial positions of particles perpendicular or parallel to the electric field greatly affect the chain patterns. In addition, the dependence of the DEP particle interaction upon the particle diameters, initial particle positions, and the DEP properties have been studied in detail. The conclusions are advantageous in elelctrokinetic microfluidic systems where it may be desirable to control, manipulate, and assemble bioparticles.
Interaction of suprathermal solar wind electron fluxes with sheared whistler waves: fan instability
Directory of Open Access Journals (Sweden)
C. Krafft
Full Text Available Several in situ measurements performed in the solar wind evidenced that solar type III radio bursts were some-times associated with locally excited Langmuir waves, high-energy electron fluxes and low-frequency electrostatic and electromagnetic waves; moreover, in some cases, the simultaneous identification of energetic electron fluxes, Langmuir and whistler waves was performed. This paper shows how whistlers can be excited in the disturbed solar wind through the so-called "fan instability" by interacting with energetic electrons at the anomalous Doppler resonance. This instability process, which is driven by the anisotropy in the energetic electron velocity distribution along the ambient magnetic field, does not require any positive slope in the suprathermal electron tail and thus can account for physical situations where plateaued reduced electron velocity distributions were observed in solar wind plasmas in association with Langmuir and whistler waves. Owing to linear calculations of growth rates, we show that for disturbed solar wind conditions (that is, when suprathermal particle fluxes propagate along the ambient magnetic field, the fan instability can excite VLF waves (whistlers and lower hybrid waves with characteristics close to those observed in space experiments.
Key words. Space plasma physics (waves and instabilities – Radio Science (waves in plasma – Solar physics, astrophysics and astronomy (radio emissions
Interaction of suprathermal solar wind electron fluxes with sheared whistler waves: fan instability
Directory of Open Access Journals (Sweden)
C. Krafft
2003-07-01
Full Text Available Several in situ measurements performed in the solar wind evidenced that solar type III radio bursts were some-times associated with locally excited Langmuir waves, high-energy electron fluxes and low-frequency electrostatic and electromagnetic waves; moreover, in some cases, the simultaneous identification of energetic electron fluxes, Langmuir and whistler waves was performed. This paper shows how whistlers can be excited in the disturbed solar wind through the so-called "fan instability" by interacting with energetic electrons at the anomalous Doppler resonance. This instability process, which is driven by the anisotropy in the energetic electron velocity distribution along the ambient magnetic field, does not require any positive slope in the suprathermal electron tail and thus can account for physical situations where plateaued reduced electron velocity distributions were observed in solar wind plasmas in association with Langmuir and whistler waves. Owing to linear calculations of growth rates, we show that for disturbed solar wind conditions (that is, when suprathermal particle fluxes propagate along the ambient magnetic field, the fan instability can excite VLF waves (whistlers and lower hybrid waves with characteristics close to those observed in space experiments.Key words. Space plasma physics (waves and instabilities – Radio Science (waves in plasma – Solar physics, astrophysics and astronomy (radio emissions
NONLINEAR WAVE INTERACTIONS AS EMISSION PROCESS OF TYPE II RADIO BURSTS
Energy Technology Data Exchange (ETDEWEB)
Ganse, Urs; Kilian, Patrick; Spanier, Felix [Lehrstuhl fuer Astronomie, Universitaet Wuerzburg, Wuerzburg (Germany); Vainio, Rami, E-mail: uganse@astro.uni-wuerzburg.de [Department of Physics, University of Helsinki, Helsinki (Finland)
2012-06-01
The emission of fundamental and harmonic frequency radio waves of type II radio bursts are assumed to be products of three-wave interaction processes of beam-excited Langmuir waves. Using a particle-in-cell code, we have performed simulations of the assumed emission region, a coronal mass ejection foreshock with two counterstreaming electron beams. Analysis of wavemodes within the simulation shows self-consistent excitation of beam-driven modes, which yield interaction products at both fundamental and harmonic emission frequencies. Through variation of the beam strength, we have investigated the dependence of energy transfer into electrostatic and electromagnetic modes, confirming the quadratic dependence of electromagnetic emission on electron beam strength.
NONLINEAR WAVE INTERACTIONS AS EMISSION PROCESS OF TYPE II RADIO BURSTS
International Nuclear Information System (INIS)
Ganse, Urs; Kilian, Patrick; Spanier, Felix; Vainio, Rami
2012-01-01
The emission of fundamental and harmonic frequency radio waves of type II radio bursts are assumed to be products of three-wave interaction processes of beam-excited Langmuir waves. Using a particle-in-cell code, we have performed simulations of the assumed emission region, a coronal mass ejection foreshock with two counterstreaming electron beams. Analysis of wavemodes within the simulation shows self-consistent excitation of beam-driven modes, which yield interaction products at both fundamental and harmonic emission frequencies. Through variation of the beam strength, we have investigated the dependence of energy transfer into electrostatic and electromagnetic modes, confirming the quadratic dependence of electromagnetic emission on electron beam strength.
pp waves of conformal gravity with self-interacting source
International Nuclear Information System (INIS)
Ayon-Beato, Eloy; Hassaine, Mokhtar
2005-01-01
Recently, Deser, Jackiw and Pi have shown that three-dimensional conformal gravity with a source given by a conformally coupled scalar field admits pp wave solutions. In this paper, we consider this model with a self-interacting potential preserving the conformal structure. A pp wave geometry is also supported by this system and, we show that this model is equivalent to topologically massive gravity with a cosmological constant whose value is given in terms of the potential strength
Accelerated particle interaction with static gases
International Nuclear Information System (INIS)
Hvelplund, P.
1977-01-01
This work describes experimental studies of stopping power and electron capture and loss associated with the passage of fast atomic particles through static gas targets. Most of the results, as well as a detailed description of the experimental procedures, have been reported in a series of articles. After an introduction to particle-gas collisions follows a short description of some theoretical approaches used in the field of stopping power and charge-changing collisions. The last part is concerned with a review of the experimental procedures employed in the papers. At the same time, the data reported in these papers are used as a starting point for further discussion of experimental studies of stopping power and charge-changing collisions. (Auth.)
Antisymmetrized four-body wave function and coexistence of single particle and cluster structures
International Nuclear Information System (INIS)
Sasakawa, T.
1979-01-01
It is shown that each Yakubovski component of the totally antisymmetric four-body wave function satisfies the same equation as the unantisymmetric wave function. In the antisymmetric total wave function, the wave functions belonging to the same kind of partition are totally antisymmetric among themselves. This leads to the coexistence of cluster models, including the single particle model as a special case of the cluster model, as a sum
Wave and particle evolution downstream of quasi-perpendicular shocks
Mckean, M. E.; Omidi, N.; Krauss-Varban, D.; Karimabadi, H.
1995-01-01
Distributions of ions heated in quasi-perpendicular bow shocks have large perpendicular temperature anisotropies that provide free energy for the growth of Alfven ion cyclotron (AIC) and mirror waves. These modes are often obsreved in the Earth's magnetosheath. Using two-dimensional hybrid simulations, we show that these waves are produced near the shock front and convected downstream rather than being produced locally downstream. The wave activity reduces the proton anisotropy to magnetosheath levels within a few tens of gyroradii of the shock but takes significantly longer to reduce the anisotropy of He(++) ions. The waves are primarily driven by proton anisotropy and the dynamics of the helium ions is controlled by the proton waves. Downstream of high Mach number shocks, mirror waves compete effectively with AIC waves. Downstream of low Mach number shocks, AIC waves dominate.
Fluctuations in interacting particle systems with memory
International Nuclear Information System (INIS)
Harris, Rosemary J
2015-01-01
We consider the effects of long-range temporal correlations in many-particle systems, focusing particularly on fluctuations about the typical behaviour. For a specific class of memory dependence we discuss the modification of the large deviation principle describing the probability of rare currents and show how superdiffusive behaviour can emerge. We illustrate the general framework with detailed calculations for a memory-dependent version of the totally asymmetric simple exclusion process as well as indicating connections to other recent work
Interactive visual exploration of a trillion particles
Schatz, Karsten; Mü ller, Christoph; Krone, Michael; Schneider, Jens; Reina, Guido; Ertl, Thomas
2017-01-01
users to easily identify interesting locations even in overviews, both the focus and context view use color tables to show data attributes on the respective scale. We demonstrate that our technique achieves interactive performance on a one trillionpar
Charged particle interaction with a chirped electromagnetic pulse
Khachatryan, A.G.; Boller, Klaus J.; van Goor, F.A.
2003-01-01
It is found that a charged particle can get a net energy gain from the interaction with an electromagnetic chirped pulse. Theoretically, the energy gain increases with the pulse amplitude and with the relative frequency variation in the pulse.
Cosmological constraints on the properties of weakly interacting massive particles
International Nuclear Information System (INIS)
Steigman, G.; Turner, M.S.
1984-10-01
Considerations of the age and density of, as well as the evolution of structure in, the Universe lead to constraints on the masses and lifetimes of weakly interacting massive particles (WIMPs). 26 references
Cosmological constraints on the properties of weakly interacting massive particles
Energy Technology Data Exchange (ETDEWEB)
Steigman, G.; Turner, M.S.
1984-10-01
Considerations of the age and density of, as well as the evolution of structure in, the Universe lead to constraints on the masses and lifetimes of weakly interacting massive particles (WIMPs). 26 references.
Lagrangian analysis of nonlinear wave-wave interactions in bounded plasmas
International Nuclear Information System (INIS)
Carr, A.R.
1979-01-01
In a weakly turbulent nonlinear wave-supporting medium, one of the important nonlinear processes which may occur is resonant three-wave interaction. Whitham's averaged Lagrangian method provides a general formulation of wave evolution laws which is easily adapted to nonlinear dispersive media. In this thesis, the strength of nonlinear interactions between three coherent, axisymmetric, low frequency, magnetohydrodynamic (Alfven) waves propagating in resonance along a cold cylindrical magnetized plasma column is calculated. Both a uniform and a parabolic density distribution have been considered. To account for a non-zero plasma temperature, pressure effects have been included. Distinctive features of the work are the use of cylindrical geometry, the presence of a finite rather than an infinite axial magnetic field, the treatment of a parabolic density distribution, and the inclusion of both ion and electron contributions in all expressions. Two astrophysical applications of the presented theory have been considered. In the first, the possibility of resonant three-wave coupling between geomagnetic micropulsations, which propagate as Alfven or magnetosonic waves along the Earth's magnetic field lines, has been investigated. The second case is the theory of energy transport through the solar chromosphere by upward propagating magnetohydrodynamic waves, which may then couple to heavily damped waves in the corona, causing the observed excess heating in that region
Final state interaction effect on correlations in narrow particles pairs
International Nuclear Information System (INIS)
Lednicky, R.; Lyuboshitz, V.L.
1990-01-01
In this paper the dependence of the two-particle correlation function on the space-time dimensions of the particle production region is discussed. The basic formulae, taking into account he effects of quantum statistics and final state interaction, and the conditions of their applicability are given
Covariant interactions of two spinless particles: all local solutions of the angular condition
International Nuclear Information System (INIS)
Leutwyler, H.; Stern, J.
1977-06-01
The solutions of the algebraic problem posed by covariant Hamiltonian quantum mechanics are discussed. If, in the transverse relative coordinates, the mass and spin operators are differential operators of at most second order, the system is shown to be described by a manifestly covariant wave equation supplemented with a covariant constraint. If, in addition, one requires the wave equation and the constraint to be local in the coordinates of both particles, the freedom left in the interaction reduces to four constants. The resulting class of systems represents a generalization of the relativistic oscillator of Feynman, Kislinger and Ravndal
Simulation of mode converted ion Bernstein wave - beam deuteron interactions on TFTR
Herrmann, Mark; Fisch, Nathaniel
1998-11-01
Experiments on TFTR have documented strong interactions between mode converted ion Bernstein waves (MCIBW) and beam deuterons(D. S. Darrow et al.), Nucl. Fusion 36, 509 (1996).^,(N. J. Fisch et al.), IAEA, Vol. 1, p. 271 (1996). This is of particular interest in the study of α channelling, since the most promising scenarios(M. C. Herrmann and N. J. Fisch, Phys. Rev. Lett. 79), 1495 (1997). rely on a suitable combination of MCIBW and Alfvén eigenmodes to achieve the cooling of the α particles. Collisional effects, realistic wave fields, and a detailed model of the wave-particle interaction have been added to the Monte Carlo simulations which are used to simulate α channelling in order to model TFTR experiments(M. C. Herrmann, Ph.D. thesis, Princeton University, 1998.). The results are found to be in qualitative agreement with the data. In addition, the simulation is used, in conjunction with the data, to demonstrate the existence of the k_\\|-flip of the MCIBW, and to infer a diffusion coefficient for the beam deuterons interacting with the wave. This diffusion coefficient significantly exceeds what would be expected on the basis of quasilinear theory with the fields specified by 1 D ray tracing of the MCIBW.
Effective field theory of thermal Casimir interactions between anisotropic particles.
Haussman, Robert C; Deserno, Markus
2014-06-01
We employ an effective field theory (EFT) approach to study thermal Casimir interactions between objects bound to a fluctuating fluid surface or interface dominated by surface tension, with a focus on the effects of particle anisotropy. The EFT prescription disentangles the constraints imposed by the particles' boundaries from the calculation of the interaction free energy by constructing an equivalent point particle description. The finite-size information is captured in a derivative expansion that encodes the particles' response to external fields. The coefficients of the expansion terms correspond to generalized tensorial polarizabilities and are found by matching the results of a linear response boundary value problem computed in both the full and effective theories. We demonstrate the versatility of the EFT approach by constructing the general effective Hamiltonian for a collection of particles of arbitrary shapes. Taking advantage of the conformal symmetry of the Hamiltonian, we discuss a straightforward conformal mapping procedure to systematically determine the polarizabilities and derive a complete description for elliptical particles. We compute the pairwise interaction energies to several orders for nonidentical ellipses as well as their leading-order triplet interactions and discuss the resulting preferred pair and multibody configurations. Furthermore, we elaborate on the complications that arise with pinned particle boundary conditions and show that the powerlike corrections expected from dimensional analysis are exponentially suppressed by the leading-order interaction energies.
Interaction range perturbation theory for three-particle problem
International Nuclear Information System (INIS)
Simenog, I.V.; Shapoval, D.V.
1988-01-01
The limit of zero interaction range is correctly defined for a system of three spinless particles and three particles in a doublet state. The scattering amplitude is expanded with respect to the interaction range r, and the corrections of order r ln r, r, and r 2 ln2 r are found. An explicit model-independent asymptotic expression is obtained for the scattering amplitude in terms of the scattering length, and its accuracy is established
Statistical effect of interactions on particle creation in expanding universe
International Nuclear Information System (INIS)
Kodama, Hideo
1982-01-01
The statistical effect of interactions which drives many-particle systems toward equilibrium is expected to change the qualitative and quantitative features of particle creation in expanding universe. To investigate this problem a simplified model called the finite-time reduction model is formulated and applied to the scalar particle creation in the radiation dominant Friedmann universe. The number density of created particles and the entropy production due to particle creation are estimated. The result for the number density is compared with that in the conventional free field theory. It is shown that the statistical effect increases the particle creation and lengthens the active creation period. As for the entropy production it is shown that it is negligible for scalar particles in the Friedmann universe. (author)
Bose gas with two- and three-particle interaction: evolution of soliton-like bubbles
International Nuclear Information System (INIS)
Barashenkov, I.V.; Kholmurodov, Kh.T.
1988-01-01
Solutions of the non-linear Schroedinger equation (NSE) for the Bose gas with two- and three-particle interaction are considered. Problems of soliton-like bubble existence, stability and evolution of the moving soliton are studied. It is shown that at D=2.3 for low-amplitude waves propagating at the transonic velocity the NSE is reduced to a two- and three-dimensional Kadomtsev-Petviashvili (KP) equation and the NSE bubble soliton transfers to the KP one
Vertical pressure gradient and particle motions in wave boundary layers
DEFF Research Database (Denmark)
Jensen, Karsten Lindegård
. The experiment is conducted in a oscillating water tunnel, for both smooth bed and rough bed. The particle motion is determined by utilizing particle tracking base on a video recording of the particle motion in the flow. In the oscillatory flow, in contrast to steady current, the particle motion is a function...
On the interaction of Rayleigh surface waves with structures
International Nuclear Information System (INIS)
Simpson, I.C.
1976-12-01
A two-dimensional soil-structure interaction analysis is carried out for transient Rayleigh surface waves that are incident on a structure. The structure is modelled by a three-degree of freedom rigid basemat to which is attached a flexible superstructure, modelled by a single mass-spring system. The structural responses to a given Rayleigh wave train are compared with those that would have been obtained if the free-field acceleration-time history had been applied as a normally incident body wave. The results clearly exhibit the 'frequency filtering' effects of the rigid basemat on the incident Rayleigh waves. It is shown that, if seismic excitation of a structure is, in fact, due to Rayleigh surface waves, then an analysis assuming normally incident body waves can considerably over-estimate structural response, both at basemat level for horizontal and vertical oscillations of the superstructure. However, in the examples considered here, relatively large rocking effects were induced by the Rayleigh waves, thus giving maximum horizontal accelerations in the superstructure that were of comparable magnitude for Rayleigh and normally incident body waves. (author)
Guided-wave acousto-optics interactions, devices, and applications
1990-01-01
The field of integrated- or guided-wave optics has experienced significant and continuous growth since its inception in the late 1960s. There has been a considerable increase in research and development activity in this field worldwide and some significant advances in the realization of working in tegrated optic devices and modules have been made in recent years. In fact, there have already been some commercial manufacturing and technical ap plications of such devices and modules. The guided-wave-acoustooptics involving Bragg interactions between guided optical waves and surface acoustic waves is one of the areas of in tegrated-optics that has reached some degree of scientific and technological maturity. This topical volume is devoted to an in-depth treatment of this emerging branch of science and technology. Presented in this volume are concise treatments on bulk-wave acoustooptics, guided-wave optics, and surface acoustic waves, and detailed studies of guided-wave acoustooptic Bragg diffraction in thr...
Wind-waves interactions in the Gulf of Eilat
Shani-Zerbib, Almog; Liberzon, Dan; T-SAIL Team
2017-11-01
The Gulf of Eilat, at the southern tip of Israel, with its elongated rectangular shape and unique diurnal wind pattern is an appealing location for wind-waves interactions research. Results of experimental work will be reported analyzing a continuous, 50 hour long, data. Using a combined array of wind and waves sensing instruments, the wave field statistics and its response to variations of wind forcing were investigated. Correlations between diurnal fluctuations in wind magnitude and direction and the wave field response will be discussed. The directional spread of waves' energy, as estimated by the Wavelet Directional Method, showed a strong response to small variations in wind flow direction attributed to the unique topography of the gulf surroundings and its bathymetry. Influenced by relatively strong winds during the light hours, the wave field was dominated by a significant amount of breakings that are well pronounced in the saturation range of waves spectra. Temporal growth and decay behavior of the waves during the morning and evening wind transition periods was examined. Sea state induced roughness, as experienced by the wind flow turbulent boundary layer, is examined in view of the critical layer theory. Israel Science Foundation Grant # 1521/15.
Wave-current interactions at the FloWave Ocean Energy Research Facility
Noble, Donald; Davey, Thomas; Steynor, Jeffrey; Bruce, Tom; Smith, Helen; Kaklis, Panagiotis
2015-04-01
Physical scale model testing is an important part of the marine renewable energy development process, allowing the study of forces and device behaviour in a controlled environment prior to deployment at sea. FloWave is a new state-of-the-art ocean energy research facility, designed to provide large scale physical modelling services to the tidal and wave sector. It has the unique ability to provide complex multi-directional waves that can be combined with currents from any direction in the 25m diameter circular tank. The facility is optimised for waves around 2s period and 0.4m height, and is capable of generating currents upwards of 1.6m/s. This offers the ability to model metocean conditions suitable for most renewable energy devices at a typical scale of between 1:10 and 1:40. The test section is 2m deep, which can be classed as intermediate-depth for most waves of interest, thus the full dispersion equation must be solved as the asymptotic simplifications do not apply. The interaction between waves and currents has been studied in the tank. This has involved producing in the tank sets of regular waves, focussed wave groups, and random sea spectra including multi-directional sea states. These waves have been both inline-with and opposing the current, as well as investigating waves at arbitrary angles to the current. Changes in wave height and wavelength have been measured, and compared with theoretical results. Using theoretical wave-current interaction models, methods have been explored to "correct" the wave height in the central test area of the tank when combined with a steady current. This allows the wave height with current to be set equal to that without a current. Thus permitting, for example, direct comparison of device motion response between tests with and without current. Alternatively, this would also permit a specific wave height and current combination to be produced in the tank, reproducing recorded conditions at a particular site of interest. The
Symbolic computation of nonlinear wave interactions on MACSYMA
International Nuclear Information System (INIS)
Bers, A.; Kulp, J.L.; Karney, C.F.F.
1976-01-01
In this paper the use of a large symbolic computation system - MACSYMA - in determining approximate analytic expressions for the nonlinear coupling of waves in an anisotropic plasma is described. MACSYMA was used to implement the solutions of a fluid plasma model nonlinear partial differential equations by perturbation expansions and subsequent iterative analytic computations. By interacting with the details of the symbolic computation, the physical processes responsible for particular nonlinear wave interactions could be uncovered and appropriate approximations introduced so as to simplify the final analytic result. Details of the MACSYMA system and its use are discussed and illustrated. (Auth.)
An overset grid approach to linear wave-structure interaction
DEFF Research Database (Denmark)
Read, Robert; Bingham, Harry B.
2012-01-01
A finite-difference based approach to wave-structure interaction is reported that employs the overset approach to grid generation. A two-dimensional code that utilizes the Overture C++ library has been developed to solve the linear radiation problem for a floating body of arbitrary form. This sof......A finite-difference based approach to wave-structure interaction is reported that employs the overset approach to grid generation. A two-dimensional code that utilizes the Overture C++ library has been developed to solve the linear radiation problem for a floating body of arbitrary form...
From basic processes to sensors: particle-matter interactions
International Nuclear Information System (INIS)
Laforge, Bertrand; Bourgeois, Christian
2005-11-01
This academic course aims at presenting and explaining techniques of detection of radiations displaying an energy higher that some tens of keV, such as those met in nuclear physics or in particle physics. In a first part, the author first analyses the operation of a biological sensor (the eye), and then presents some generalities about matter: Rutherford experiment, the atom, molecules and solids. The second part deals with interactions between radiations and matter. The author there addresses interactions of heavy charged particles (ionization with high or low energy transfer), interactions of electrons (ionization, Bremsstrahlung), multiple scattering and straggling, the Cherenkov effect, transition radiation, the interaction of γ radiations in matter (Compton effect, photoelectric effect), the interaction of neutrons in matter. Appendices address γ spectrometry, the radiation of a charged particle moving in a dielectric medium, and issues related to statistical fluctuations (distribution functions, fluctuation propagation, energy resolution, noises)
International Nuclear Information System (INIS)
Hwang, D.Q.; Horton, R.D.; Evans, R.W.
1999-01-01
The alpha particles in a fusion reactor play a key role in the sustaining the fusion reaction. It is the heating provided by the alpha particles that help a fusion reactor operating in the ignition regime. It is, therefore, essential to understand the behavior of the alpha population both in real space and velocity space in order to design the optimal confinement device for fusion application. Moreover, the alphas represent a strong source of free energy that may generate plasma instabilities. Theoretical studies has identified the Toroidal Alfven Eigenmode (TAE) as an instability that can be excited by the alpha population in a toroidal device. Since the alpha has an energy of 3.5 MeV, a good confinement device will retain it in the interior of the plasma. Therefore, alpha measurement system need to probe the interior of a high density plasma. Due to the conducting nature of a plasma, wave with frequencies below the plasma frequency can not penetrate into the interior of the plasma where the alphas reside. This project uses a wave that can interact with the perpendicular motion of the alphas to probe its characteristics. However, this wave (the lower hybrid wave) is below the plasma frequency and can not be directly launched from the plasma edge. This project was designed to non-linearly excite the lower hybrid in the interior of a magnetized plasma and measure its interaction with a fast ion population
Particle Interactions in DNA-laden Flows
International Nuclear Information System (INIS)
Bybee, M D; Miller, G H; Trebotich, D
2005-01-01
Microfluidic devices are becoming state-of-the-art in many significant applications including pathogen detection, continuous monitoring, and drug delivery. Numerical algorithms which can simulate flows of complex fluids within these devices are needed for their development and optimization. A method is being developed at LLNL by Trebotich et. al. [30] for simulations of DNA-laden flows in complex microscale geometries such as packed bed reactors and pillar chips. In this method an incompressible Newtonian fluid is discretized with Cartesian grid embedded boundary methods, and the DNA is represented by a bead-rod polymer model. The fluid and polymer are coupled through a body force. In its current state, polymer-surface interactions are treated as elastic collisions between beads and surface, and polymer-polymer interactions are neglected. Implementation of polymer-polymer interactions is the main objective of this work. It is achieved by two methods: (1) a rigid constraint whereby rods elastically bounce off one another, and (2) a smooth potential acting between rods. In addition, a smooth potential is also implemented for the polymer-surface interactions. Background information will also be presented as well as related work by other researchers
Particle Interactions in DNA-laden Flows
Energy Technology Data Exchange (ETDEWEB)
Bybee, M D; Miller, G H; Trebotich, D
2005-12-20
Microfluidic devices are becoming state-of-the-art in many significant applications including pathogen detection, continuous monitoring, and drug delivery. Numerical algorithms which can simulate flows of complex fluids within these devices are needed for their development and optimization. A method is being developed at LLNL by Trebotich et. al. [30] for simulations of DNA-laden flows in complex microscale geometries such as packed bed reactors and pillar chips. In this method an incompressible Newtonian fluid is discretized with Cartesian grid embedded boundary methods, and the DNA is represented by a bead-rod polymer model. The fluid and polymer are coupled through a body force. In its current state, polymer-surface interactions are treated as elastic collisions between beads and surface, and polymer-polymer interactions are neglected. Implementation of polymer-polymer interactions is the main objective of this work. It is achieved by two methods: (1) a rigid constraint whereby rods elastically bounce off one another, and (2) a smooth potential acting between rods. In addition, a smooth potential is also implemented for the polymer-surface interactions. Background information will also be presented as well as related work by other researchers.
INTERACTING MANY-PARTICLE SYSTEMS OF DIFFERENT PARTICLE TYPES CONVERGE TO A SORTED STATE
DEFF Research Database (Denmark)
Kokkendorff, Simon Lyngby; Starke, Jens; Hummel, N.
2010-01-01
We consider a model class of interacting many-particle systems consisting of different types of particles defined by a gradient flow. The corresponding potential expresses attractive and repulsive interactions between particles of the same type and different types, respectively. The introduced...... system converges by self-organized pattern formation to a sorted state where particles of the same type share a common position and those of different types are separated from each other. This is proved in the sense that we show that the property of being sorted is asymptotically stable and all other...... states are unstable. The models are motivated from physics, chemistry, and biology, and the principal investigations can be useful for many systems with interacting particles or agents. The models match particularly well a system in neuroscience, namely the axonal pathfinding and sorting in the olfactory...
Rarefaction shock waves and Hugoniot curve in the presence of free and trapped particles
International Nuclear Information System (INIS)
Niknam, A. R.; Hashemzadeh, M.; Shokri, B.; Rouhani, M. R.
2009-01-01
The effects of the relativistic ponderomotive force and trapped particles in the presence of ponderomotive force on the rarefaction shock waves are investigated. The ponderomotive force alters the electron density distribution. This force and relativistic mass affect the plasma frequency. These physical parameters modify the total pressure and the existence condition of the rarefaction shock wave. Furthermore, the trapping of particles by the high frequency electromagnetic field considerably changes the existence condition of the rarefaction shock wave. The total pressure and Hugoniot curve are obtained by considering the relativistic ponderomotive force and trapped particles.
Rarefaction shock waves and Hugoniot curve in the presence of free and trapped particles
Niknam, A. R.; Hashemzadeh, M.; Shokri, B.; Rouhani, M. R.
2009-12-01
The effects of the relativistic ponderomotive force and trapped particles in the presence of ponderomotive force on the rarefaction shock waves are investigated. The ponderomotive force alters the electron density distribution. This force and relativistic mass affect the plasma frequency. These physical parameters modify the total pressure and the existence condition of the rarefaction shock wave. Furthermore, the trapping of particles by the high frequency electromagnetic field considerably changes the existence condition of the rarefaction shock wave. The total pressure and Hugoniot curve are obtained by considering the relativistic ponderomotive force and trapped particles.
Higher-order geodesic deviation for charged particles and resonance induced by gravitational waves
Heydari-Fard, M.; Hasani, S. N.
We generalize the higher-order geodesic deviation for the structure-less test particles to the higher-order geodesic deviation equations of the charged particles [R. Kerner, J. W. van Holten and R. Colistete Jr., Class. Quantum Grav. 18 (2001) 4725]. By solving these equations for charged particles moving in a constant magnetic field in the spacetime of a gravitational wave, we show for both cases when the gravitational wave is parallel and perpendicular to the constant magnetic field, a magnetic resonance appears at wg = Ω. This feature might be useful to detect the gravitational wave with high frequencies.
Basic principles approach for studying nonlinear Alfven wave-alpha particle dynamics
International Nuclear Information System (INIS)
Berk, H.L.; Breizman, B.N.; Pekker, M.
1994-01-01
An analytical model and a numerical procedure are presented which give a kinetic nonlinear description of the Alfven-wave instabilities driven by the source of energetic particles in a plasma. The steady-state and bursting nonlinear scenarios predicted by the analytical theory are verified in the test numerical simulation of the bump-on-tail instability. A mathematical similarity between the bump-on-tail problem for plasma waves and the Alfven wave problem gives a guideline for the interpretation of the bursts in the wave energy and fast particle losses observed in the tokamak experiments with neutral beam injection
Modeling of Mud-Wave Interaction: Mud-Induced Wave Transport & Wave-Induced Mud Transport
National Research Council Canada - National Science Library
Winterwerp, Johan C
2007-01-01
.... Also a new rheological model has been proposed to describe liquefaction of soft mud by waves, and the subsequent strength recovery after the passage of the waves. A scheme is presented on how to implement these formulations in Delft3D.
Directory of Open Access Journals (Sweden)
E. E. Woodfield
2013-10-01
Full Text Available Jupiter has the most intense radiation belts of all the outer planets. It is not yet known how electrons can be accelerated to energies of 10 MeV or more. It has been suggested that cyclotron-resonant wave-particle interactions by chorus waves could accelerate electrons to a few MeV near the orbit of Io. Here we use the chorus wave intensities observed by the Galileo spacecraft to calculate the changes in electron flux as a result of pitch angle and energy diffusion. We show that, when the bandwidth of the waves and its variation with L are taken into account, pitch angle and energy diffusion due to chorus waves is a factor of 8 larger at L-shells greater than 10 than previously shown. We have used the latitudinal wave intensity profile from Galileo data to model the time evolution of the electron flux using the British Antarctic Survey Radiation Belt (BAS model. This profile confines intense chorus waves near the magnetic equator with a peak intensity at ∼5° latitude. Electron fluxes in the BAS model increase by an order of magnitude for energies around 3 MeV. Extending our results to L = 14 shows that cyclotron-resonant interactions with chorus waves are equally important for electron acceleration beyond L = 10. These results suggest that there is significant electron acceleration by cyclotron-resonant interactions at Jupiter contributing to the creation of Jupiter's radiation belts and also increasing the range of L-shells over which this mechanism should be considered.
Nonlinear instability and chaos in plasma wave-wave interactions, I., Introduction
International Nuclear Information System (INIS)
Kueny, C.S.; Morrison, P.J.
1994-11-01
Conventional linear stability analyses may fail for fluid systems with an indefinite free energy functional. When such a system is linearly stable, it is said to possess negative energy modes. Instability may then occur either via dissipation of the negative energy modes, or nonlinearly via resonant wave-wave coupling, leading to explosive growth. In the dissipationless case, it is conjectured that intrinsic chaotic behavior may allow initially nonresonant systems to reach resonance by diffusion in phase space. In this and a companion paper [submitted to Physics of Plasmas], this phenomenon is demonstrated for a simple equilibrium involving cold counterstreaming ions. The system is described in the fluid approximation by a Hamiltonian functional and associated noncanonical Poisson bracket. By Fourier decomposition and appropriate coordinate transformations, the Hamiltonian for the perturbed energy is expressed in action-angle form. The normal modes correspond to Doppler-shifted ion-acoustic waves of positive and negative energy. Nonlinear coupling leads to decay instability via two-wave interactions, and to either decay or explosive instability via three-wave interactions. These instabilities are described for various (integrable) systems of waves interacting via single nonlinear terms. This discussion provides the foundation for the treatment of nonintegrable systems in the companion paper
Nonlinear instability and chaos in plasma wave--wave interactions. I. Introduction
International Nuclear Information System (INIS)
Kueny, C.S.; Morrison, P.J.
1995-01-01
Conventional linear stability analyses may fail for fluid systems with an indefinite free-energy functional. When such a system is linearly stable, it is said to possess negative energy modes. Instability may then occur either via dissipation of the negative energy modes, or nonlinearly via resonant wave--wave coupling, leading to explosive growth. In the dissipationless case, it is conjectured that intrinsic chaotic behavior may allow initially nonresonant systems to reach resonance by diffusion in phase space. In this and a companion paper (submitted to Phys. Plasmas), this phenomenon is demonstrated for a simple equilibrium involving cold counterstreaming ions. The system is described in the fluid approximation by a Hamiltonian functional and associated noncanonical Poisson bracket. By Fourier decomposition and appropriate coordinate transformations, the Hamiltonian for the perturbed energy is expressed in action-angle form. The normal modes correspond to Doppler-shifted ion-acoustic waves of positive and negative energy. Nonlinear coupling leads to decay instability via two-wave interactions, and to either decay or explosive instability via three-wave interactions. These instabilities are described for various integrable systems of waves interacting via single nonlinear terms. This discussion provides the foundation for the treatment of nonintegrable systems in the companion paper. copyright 1995 American Institute of Physics
Inter-particle Interactions in Composites of Antiferromagnetic Nanoparticles
DEFF Research Database (Denmark)
Frandsen, Cathrine; Mørup, Steen
2003-01-01
-Fe2O3 and Fe-57-doped NiO particles. The effect of NiO particles on alpha-FeA particles was a shorter relaxation time and an induced Morin transition, which usually is absent in alpha-Fe2O3 nanoparticles. Spectra of alpha-Fe2O3 particles, prepared by drying suspensions with added Co2+ and Ni2+ ions......We have prepared mixtures of alpha-Fe2O3, CoO, and NiO nanoparticles by drying aqueous suspensions of the particles. The magnetic properties were studied by Mossbauer spectroscopy. The measurements showed that interactions with CoO particles suppress the superparamagnetic relaxation of both alpha......, showed that the suspension medium can affect the magnetic properties of the alpha-FeA particles significantly, but not in the same way as the CoO or NiO nanoparticles. Therefore, a strong inter-particle exchange interaction between particles of different materials seems to be responsible for the magnetic...
Backward particle production in neutrino neon interactions
International Nuclear Information System (INIS)
Matsinos, E.; Simopoulou, E.; Giannakopoulos, N.; Vayaki, A.; Guy, J.; Venus, W.; Allport, P.; Cooper-Sarkar, A.M.; Sansum, R.A.; Berggren, M.; Morrison, D.R.O.; Parker, M.A.; Wachsmuth, H.; Calicchio, M.; Erriquez, O.; Coghen, T.; Jones, G.T.; O'Neale, S.O.; Varvell, K.; Marage, P.; Sacton, J.; Mobayyen, M.M.; Schmitz, N.; Wittek, W.; Apeldoorn, G.W. van
1989-01-01
Backward proton and pion production is studied in ν and anti ν charged current interactions in neon. The results are compared with other experiments and theory. The complete backward proton data are compatible with protons produced by reinteractions in the nucleus. However in events with only one proton, muon variables appear correlated to those for the backward proton, as expected by the two-nucleon correlation model. (orig.)
P-matrix description of charged particles interaction
International Nuclear Information System (INIS)
Babenko, V.A.; Petrov, N.M.
1992-01-01
The paper deals with formalism of the P-matrix description of two charged particles interaction. Separation in the explicit form of the background part corresponding to the purely Coulomb interaction in the P-matrix is proposed. Expressions for the purely Coulomb P-matrix, its poles, residues and purely Coulomb P-matrix approach eigenfunctions are obtained. (author). 12 refs
Plasma-surface interactions under high heat and particle fluxes
De Temmerman, G.; Bystrov, K.; Liu, F.; Liu, W.; Morgan, T.; Tanyeli, I.; van den Berg, M.; Xu, H.; Zielinski, J.
2013-01-01
The plasma-surface interactions expected in the divertor of a future fusion reactor are characterized by extreme heat and particle fluxes interacting with the plasma-facing surfaces. Powerful linear plasma generators are used to reproduce the expected plasma conditions and allow plasma-surface
Gravitational waves from a spinning particle scattered by a relativistic star: Axial mode case
International Nuclear Information System (INIS)
Tominaga, Kazuhiro; Saijo, Motoyuki; Maeda, Kei-ichi
2001-01-01
We use a perturbation method to study gravitational waves from a spinning test particle scattered by a relativistic star. The present analysis is restricted to axial modes. By calculating the energy spectrum, the wave forms, and the total energy and angular momentum of gravitational waves, we analyze the dependence of the emitted gravitational waves on particle spin. For a normal neutron star, the energy spectrum has one broad peak whose characteristic frequency corresponds to the angular velocity at the turning point (a periastron). Since the turning point is determined by the orbital parameter, there exists a dependence of the gravitational wave on particle spin. We find that the total energy of l=2 gravitational waves gets larger as the spin increases in the antiparallel direction to the orbital angular momentum. For an ultracompact star, in addition to such an orbital contribution, we find the quasinormal modes excited by a scattered particle, whose excitation rate to gravitational waves depends on the particle spin. We also discuss the ratio of the total angular momentum to the total energy of gravitational waves and explain its spin dependence
O Wave Interactions: Explosive Resonant Triads and Critical Layers.
Mahoney, Daniel J.
This thesis considers the phenomenon of explosive resonant triads in weakly nonlinear, dispersive wave systems. These are nearly linear waves with slowly varying amplitudes which become unbounded in finite time. It is shown that such interactions are much stronger than previously thought. These waves can be thought of as a nonlinear instability, in the sense that a weakly nonlinear perturbation to some system grows to such magnitudes that the behavior of the system is governed by strongly nonlinear effects. This may occur for systems which are linearly or neutrally stable. This is contrasted with previous resolutions of this problem, which treated such perturbations as being large amplitude, nearly linear waves. Analytical and numerical evidence is presented to support these claims. These waves represent a potentially important effect in a variety of physical systems, most notably plasma physics. Attention here is turned to their occurrence in fluid mechanics. Here previous work is extended to include flow systems with continuously varying basic velocities and densities. Many of the problems encountered here will be found to be of a singular nature themselves, and the techniques for analyzing these difficulties will be developed. This will involve the concept of a critical layer in a fluid, a level at which a wave phase speed equals the unperturbed fluid velocity in the direction of propagation. Examples of such waves in this context will be presented. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253 -1690.).
Are Higgs particles strongly interacting(question mark)
International Nuclear Information System (INIS)
Shanker, O.
1982-02-01
The order of magnitude of Yukawa couplings in some theories with flavour violating Higgs particles is estimated. Based on these couplings, mass bounds for flavour violating Higgs particles are derived from the Ksub(L)-Ksub(S) mass difference. The Higgs particles have to be very heavy, implying that the Higgs sector quartic couplings are very large. Thus, these theories seem to require a strongly interacting Higgs sector unless one adjusts to the Higgs-fermion Yukawa couplings to within two orders of magnitude, so as to suppress the coupling of Higgs particles to the flavour-violating anti sd current. Most models with flavour violating Higgs particles have the same general features, so the conclusions are likely to hold for a wide class of models with flavour violating Higgs particles
Modulation of energetic particle fluxes by a mixed mode of transverse and compressional waves
International Nuclear Information System (INIS)
Lin, C.S.; Parks, G.K.
1982-01-01
Modulation characteristics of particle fluxes in the presence of a mixed mode of compressional and transverse magnetic waves at hydromagnetic frequencies have been studied by means of kinetic perturbation of the distribution function. The magnetospheric medium in which the particles are modulated contains both the magnetic and pressure gradients. It is found that the modulation features are strongly dependent on the energy and pitch angle of the particles. Drifting particles can resonate with waves whose phase velocities are near their drift velocities. When this happens, the amplitude of the modulations become significantly large and large phase shifts will occur. Resonance is important for particles with mid pitch angles (40 0 --70 0 ). The phase shift between the particle modulations and the magnetic field oscillations are strongly controlled by combined effects of transverse and compressional wave components and/or the occurrence of drift resonance. We have performed numerical calculations by using the dispersion relation of drift mirror Alfven waves as an example of waves with both compressional and transverse components. The results derived in this study may be of importance in studying the relationship of particles and Pc 4--5 waves that are observed during magnetically disturbed times
Di Martino, Piera; Joiris, Etienne; Martelli, Sante
2004-09-01
The aim of this study is to assess an experimental approach for technological development of a direct compression formulation. A simple formula was considered composed by an active ingredient, a diluent and a lubricant. The active ingredient and diluent were selected as an example according to their typical densification mechanism: the nitrofurantoine, a fragmenting material, and the cellulose microcrystalline (Vivapur), which is a typical visco-elastic material, equally displaying good bind and disintegrant properties. For each ingredient, samples of different particle size distribution were selected. Initially, tabletability of pure materials was studied by a rotary press without magnesium stearate. Vivapur tabletability decreases with increase in particle size. The addition of magnesium stearate as lubricant decreases tabletability of Vivapur of greater particle size, while it kept unmodified that of Vivapur of lower particle size. Differences in tabletability can be related to differences in particle-particle interactions; for Vivapur of higher particle size (Vivapur 200, 102 and 101), the lower surface area develops lower surface available for bonds, while for Vivapur of lower particle size (99 and 105) the greater surface area allows high particle proximity favouring particle cohesivity. Nitrofurantoine shows great differences in compression behaviour according to its particle size distribution. Large crystals show poorer tabletability than fine crystals, further decreased by lubricant addition. The large crystals poor tabletability is due to their poor compactibility, in spite of high compressibility and plastic intrinsic deformability; in fact, in spite of the high densification tendency, the nature of the involved bonds is very weak. Nitrofurantoine samples were then mixed with Vivapurs in different proportions. Compression behaviour of binary mixes (tabletability and compressibility) was then evaluated according to diluents proportion in the mixes. The
The weak interaction in nuclear, particle and astrophysics
International Nuclear Information System (INIS)
Grotz, K.; Klapdor, H.V.
1989-01-01
This book is an introduction to the concepts of weak interactions and their importance and consequences for nuclear physics, particle physics, neutrino physics, astrophysics and cosmology. After a general introduction to elementary particles and interactions the Fermi theory of weak interactions is described together with its connection with nuclear structure and beta decay including the double beta decay. Then, after a general description of gauge theories the Weinberg-Salam theory of the electroweak interactions is introduced. Thereafter the weak interactions are considered in the framework of grand unification. Then the physics of neutrinos is discussed. Thereafter connections of weak interactions with astrophysics are considered with special regards to the gravitational collapse and the synthesis of heavy elements in the r-process. Finally, the connections of grand unified theories and cosmology are considered. (HSI) With 141 figs., 39 tabs
Experimental research on crossing shock wave boundary layer interactions
Settles, G. S.; Garrison, T. J.
1994-10-01
An experimental research effort of the Penn State Gas Dynamics Laboratory on the subject of crossing shock wave boundary layer interactions is reported. This three year study was supported by AFOSR Grant 89-0315. A variety of experimental techniques were employed to study the above phenomena including planar laser scattering flowfield visualization, kerosene lampblack surface flow visualization, laser-interferometer skin friction surveys, wall static pressure measurements, and flowfield five-hole probe surveys. For a model configuration producing two intersecting shock waves, measurements were made for a range of oblique shock strengths at freestream Mach numbers of 3.0 and 3.85. Additionally, measurements were made at Mach 3.85 for a configuration producing three intersecting waves. The combined experimental dataset was used to formulate the first detailed flowfield models of the crossing-shock and triple-shock wave/boundary layer interactions. The structure of these interactions was found to be similar over a broad range of interaction strengths and is dominated by a large, separated, viscous flow region.
Solitary wave exchange potential and nucleon-nucleon interaction
International Nuclear Information System (INIS)
Prema, K.; Raghavan, S.S.; Sekhar Raghavan
1986-11-01
Nucleon-nucleon interaction is studied using a phenomenological potential model called solitary wave exchange potential model. It is shown that this simple model reproduces the singlet and triplet scattering data and the deuteron parameters reasonably well. (author). 6 refs, 2 figs, 1 tab
The interaction of katabatic winds and mountain waves
Energy Technology Data Exchange (ETDEWEB)
Poulos, Gregory Steve [Colorado State Univ., Fort Collins, CO (United States)
1997-01-01
The variation in the oft-observed, thermally-forced, nocturnal katabatic winds along the east side of the Rocky Mountains can be explained by either internal variability or interactions with various other forcings. Though generally katabatic flows have been studied as an entity protected from external forcing by strong thermal stratification, this work investigates how drainage winds along the Colorado Front Range interact with, in particular, topographically forced mountain waves. Previous work has shown, based on measurements taken during the Atmospheric Studies in Complex Terrain 1993 field program, that the actual dispersion in katabatic flows is often greater than reflected in models of dispersion. The interaction of these phenomena is complicated and non-linear since the amplitude, wavelength and vertical structure of mountain waves developed by flow over the Rocky Mountain barrier are themselves partly determined by the evolving atmospheric stability in which the drainage flows develop. Perturbations to katabatic flow by mountain waves, relative to their more steady form in quiescent conditions, are found to be caused by both turbulence and dynamic pressure effects. The effect of turbulent interaction is to create changes to katabatic now depth, katabatic flow speed, katabatic jet height and, vertical thermal stratification. The pressure effect is found to primarily influence the variability of a given katabatic now through the evolution of integrated column wave forcing on surface pressure. Variability is found to occur on two scales, on the mesoscale due to meso-gamma scale mountain wave evolution, and on the microscale, due to wave breaking. Since existing parameterizations for the statically stable case are predominantly based on nearly flat terrain atmospheric measurements under idealized or nearly quiescent conditions, it is no surprise that these parameterizations often contribute to errors in prediction, particularly in complex terrain.
General experiments concerning particle-matter interactions
International Nuclear Information System (INIS)
Dauvergne, D.
2006-07-01
The author gathers in this document several papers he has already published in order to shed light on different aspects concerning ion-crystal interactions. This document is divided into 3 chapters. In the first chapter the author presents results obtained from experiments dedicated to charge exchanges and energy released by heavy ions in channeling conditions. Different processes involved in ion-electron interactions are considered: The tri-electronic recombination, the electron capture through nuclear excitation (NEEC), resonant transfer and excitation (RTE), resonant transfer and double excitation (RTDE) and electron impact ionization (EII). The second chapter deals with the measurement of nuclear fission times through crystal blocking experiments. The crystal blocking technique allows the measurement in a model-independent way of the recoil distance covered by the excited nucleus during the whole fission process (starting from the initial collision and ending at the scission point). The last chapter is dedicated to the photon impact ionization through the conversion of a high-energy photon into an electron-positron pair
Theory of reflection reflection and transmission of electromagnetic, particle and acoustic waves
Lekner, John
2016-01-01
This book deals with the reflection of electromagnetic and particle waves by interfaces. The interfaces can be sharp or diffuse. The topics of the book contain absorption, inverse problems, anisotropy, pulses and finite beams, rough surfaces, matrix methods, numerical methods, reflection of particle waves and neutron reflection. Exact general results are presented, followed by long wave reflection, variational theory, reflection amplitude equations of the Riccati type, and reflection of short waves. The Second Edition of the Theory of Reflection is an updated and much enlarged revision of the 1987 monograph. There are new chapters on periodically stratified media, ellipsometry, chiral media, neutron reflection and reflection of acoustic waves. The chapter on anisotropy is much extended, with a complete treatment of the reflection and transmission properties of arbitrarily oriented uniaxial crystals. The book gives a systematic and unified treatment reflection and transmission of electromagnetic and particle...
Current-drive by lower hybrid waves in the presence of energetic alpha-particles
Energy Technology Data Exchange (ETDEWEB)
Fisch, N.J.; Rax, J.M.
1991-10-01
Many experiments have now proved the effectiveness of lower hybrid waves for driving toroidal current in tokamaks. The use of these waves, however, to provide all the current in a reactor is thought to be uncertain because the waves may not penetrate the center of the more energetic reactor plasma, and, if they did, the wave power may be absorbed by alpha particles rather than by electrons. This paper explores the conditions under which lower-hybrid waves might actually drive all the current. 26 refs.
Covariant two-particle wave functions for model quasipotentials admitting exact solutions
International Nuclear Information System (INIS)
Kapshaj, V.N.; Skachkov, N.B.
1983-01-01
Two formulations of quasipotential equations in the relativistic configurational representation are considered for the wave function of the internal motion of the bound system of two relativistic particles. Exact solutions of these equations are found for some model quasipotentials
Covariant two-particle wave functions for model quasipotential allowing exact solutions
International Nuclear Information System (INIS)
Kapshaj, V.N.; Skachkov, N.B.
1982-01-01
Two formulations of quasipotential equations in the relativistic configurational representation are considered for the wave function of relative motion of a bound state of two relativistic particles. Exact solutions of these equations are found for some model quasipotentials
Incorporation particle creation and annihilation into Bohm's Pilot Wave model
Energy Technology Data Exchange (ETDEWEB)
Sverdlov, Roman [Raman Research Institute, C.V. Raman Avenue, Sadashiva Nagar, Bangalore, Karnataka, 560080 (India)
2011-07-08
The purpose of this paper is to come up with a Pilot Wave model of quantum field theory that incorporates particle creation and annihilation without sacrificing determinism; this theory is subsequently coupled with gravity.
Krupp, N.; Tsurutani, B. T.; Lanzerotti, L. J.; Maclennan, C. G.
1996-01-01
We report on measurements of energetic particle modulations observed by the HI-SCALE instrument aboard the Ulysses Spacecraft that were associated with the only hydromagnetic wave event measured inside the Jovian magnetosphere by the Ulysses magnetometer investigation.
Tunneling time distribution by means of Nelson's quantum mechanics and wave-particle duality
International Nuclear Information System (INIS)
Hara, Koh'ichiro; Ohba, Ichiro
2003-01-01
We calculate a tunneling time distribution by means of Nelson's quantum mechanics and investigate its statistical properties. The relationship between the average and deviation of tunneling time suggests the existence of 'wave-particle duality' in the tunneling phenomena
Charged particle and photon acceleration by wakefield plasma waves in non-uniform plasmas
International Nuclear Information System (INIS)
Bulanov, S.V.; Kirsanov, V.I.; Sakharov, A.S.; Pegoraro, F.
1993-01-01
We discuss the acceleration of charged particles and the upshift of the frequency of short wave packets of laser radiation. The acceleration and the upshift are caused by wake plasma waves excited by a strong laser pulse in a non-uniform plasma. We show that unlimited acceleration of charged particles is possible for specific spatial dependencies of the plasma density. In this unlimited acceleration regime, particles have a fixed phase relationship with respect to the plasma wave, while their energy increases with time. When the wave breaking limit is approached and surpassed, the efficiency of the acceleration of the charged particles and of the frequency upshift of the photons can be increased significantly. (author) 3 refs
Introduction of the chronon in the theory of electron and the wave-particle duality
International Nuclear Information System (INIS)
Caldirola, P.
1984-01-01
The author summarizes the more important results obtained in the electron theory based on the chronon and stresses some peculiarities of the wave-particle duality directly connected with the introduction of the chronon. (Auth.)
Interaction of Spatially Localized LHW with Banana Particles
Czech Academy of Sciences Publication Activity Database
Krlín, Ladislav; Fuchs, Vladimír; Pánek, Radomír; Papřok, Richard; Seidl, Jakub
2014-01-01
Roč. 1, č. 3 (2014), s. 166-168 ISSN 2336-2626. [SPPT 2014 - 26th Symposium on Plasma Physics and Technology/26./. Prague, 16.06.2014-19.06.2014] R&D Projects: GA ČR GAP205/11/2341 Institutional support: RVO:61389021 Keywords : anomalous acceleration * stochasticity * lower hybrid waves * banana particles * tokamaks Subject RIV: BL - Plasma and Gas Discharge Physics http://fyzika.feld.cvut.cz/misc/ppt/articles/2014/krlin.pdf
Secondary Flows and Sediment Transport due to Wave - Current Interaction
Ismail, Nabil; Wiegel, Robert
2015-04-01
Objectives: The main purpose of this study is to determine the modifications of coastal processes driven by wave-current interaction and thus to confirm hydrodynamic mechanisms associated with the interaction at river mouths and tidal inlets where anthropogenic impacts were introduced. Further, the aim of the work has been to characterize the effect of the relative strength of momentum action of waves to the opposing current on the nearshore circulation where river flow was previously effective to entrain sediments along the shoreline. Such analytical information are useful to provide guidelines for sustainable design of coastal defense structures. Methodology and Analysis: Use is made of an earlier study reported by the authors (1983) on the interaction of horizontal momentum jets and opposing shallow water waves at shorelines, and of an unpublished laboratory study (1980). The turbulent horizontal discharge was shore-normal, directed offshore, and the incident wave direction was shore-normal, travelling toward shore. Flow visualization at the smooth bottom and the water surface, velocity and water surface elevation measurements were made. Results were obtained for wave , current modifications as well as the flow pattern in the jet and the induced circulation on both sides of the jet, for a range of wave and jet characteristics. The experimental data, obtained from measurement in the 3-D laboratory basin, showed several distinct flow pattern regimes on the bottom and the water surface. The observed flow circulation regimes were found to depend on the ratio of the wave momentum action on the jet to the jet initial momentum. Based on the time and length scales of wave and current parameters and using the time average of the depth integrated conservation equations, it is found that the relative strength of the wave action on the jet could be represented by a dimensionless expression; Rsm ( ) 12ρSa20g-L0h-Cg- 2 Rsm ≈ (C0 - U) /ρ0U w (1) In the above dimensionless
Visualization of acoustic particle interaction and agglomeration: Theory evaluation
International Nuclear Information System (INIS)
Hoffmann, T.L.; Koopmann, G.H.
1997-01-01
In this paper experimentally observed trajectories of particles undergoing acoustically induced interaction and agglomeration processes are compared to and validated with numerically generated trajectories based on existing agglomeration theories. Models for orthokinetic, scattering, mutual radiation pressure, and hydrodynamic particle interaction are considered in the analysis. The characteristic features of the classical orthokinetic agglomeration hypothesis, such as collision processes and agglomerations due to the relative entrainment motion, are not observed in the digital images. The measured entrainment rates of the particles are found to be consistently lower than the theoretically predicted values. Some of the experiments reveal certain characteristics which may possibly be related to mutual scattering interaction. The study's most significant discovery is the so-called tuning fork agglomeration [T. L. Hoffmann and G. H. Koopmann, J. Acoust. Soc. Am. 99, 2130 endash 2141 (1996)]. It is shown that this phenomenon contradicts the theories for mutual scattering interaction and mutual radiation pressure interaction, but agrees with the acoustic wake effect model in its intrinsic feature of attraction between particles aligned along the acoustic axis. A model by Dianov et al. [Sov. Phys. Acoust. 13 (3), 314 endash 319 (1968)] is used to describe this effect based on asymmetric flow fields around particles under Oseen flow conditions. It is concluded that this model is consistent with the general characteristics of the tuning fork agglomerations, but lacks certain refinements with respect to accurate quantification of the effect. copyright 1997 Acoustical Society of America
Dynamic behavior of microscale particles controlled by standing bulk acoustic waves
Energy Technology Data Exchange (ETDEWEB)
Greenhall, J.; Raeymaekers, B., E-mail: bart.raeymaekers@utah.edu [Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Guevara Vasquez, F. [Department of Mathematics, University of Utah, Salt Lake City, Utah 84112 (United States)
2014-10-06
We analyze the dynamic behavior of a spherical microparticle submerged in a fluid medium, driven to the node of a standing bulk acoustic wave created by two opposing transducers. We derive the dynamics of the fluid-particle system taking into account the acoustic radiation force and the time-dependent and time-independent drag force acting on the particle. Using this dynamic model, we characterize the transient and steady-state behavior of the fluid-particle system as a function of the particle and fluid properties and the transducer operating parameters. The results show that the settling time and percent overshoot of the particle trajectory are dependent on the ratio of the acoustic radiation force and time-independent damping force. In addition, we show that the particle oscillates around the node of the standing wave with an amplitude that depends on the ratio of the time-dependent drag forces and the particle inertia.
Rao, Chengping; Zhang, Youlin; Wan, Decheng
2017-12-01
Fluid-Structure Interaction (FSI) caused by fluid impacting onto a flexible structure commonly occurs in naval architecture and ocean engineering. Research on the problem of wave-structure interaction is important to ensure the safety of offshore structures. This paper presents the Moving Particle Semi-implicit and Finite Element Coupled Method (MPS-FEM) to simulate FSI problems. The Moving Particle Semi-implicit (MPS) method is used to calculate the fluid domain, while the Finite Element Method (FEM) is used to address the structure domain. The scheme for the coupling of MPS and FEM is introduced first. Then, numerical validation and convergent study are performed to verify the accuracy of the solver for solitary wave generation and FSI problems. The interaction between the solitary wave and an elastic structure is investigated by using the MPS-FEM coupled method.
Improved model of quasi-particle turbulence (with applications to Alfven and drift wave turbulence)
International Nuclear Information System (INIS)
Mendonca, J. T.; Hizanidis, K.
2011-01-01
We consider the classical problem of wave stability and dispersion in a turbulent plasma background. We adopt a kinetic description for the quasi-particle turbulence. We describe an improved theoretical approach, which goes beyond the geometric optics approximation and retains the recoil effects associated with the emission and absorption of low frequency waves by nearly resonant quasi-particles. We illustrate the present approach by considering two particular examples. One is the excitation of zonal flows by drift wave turbulence or driftons. The other is the coupling between ion acoustic waves and Alfven wave turbulence, eventually leading to saturation of Alfven wave growth. Both examples are relevant to anomalous transport in magnetic fusion devices. Connection with previous results is established. We show that these results are recovered in the geometric optics approximation.
Kinetic theory of interaction of high frequency waves with a rotating plasma
International Nuclear Information System (INIS)
Chiu, S. C.; Chan, V. S.; Chu, M. S.; Lin-Liu, Y. R.
2000-01-01
The equations of motion of charged particles of a strongly magnetized flowing plasma under the influence of high frequency waves are derived in the guiding center approximation. A quasilinear theory of the interactions of waves with rotating plasmas is formulated. This is applied to investigate the effect of radio frequency waves on a rotating tokamak plasma with a heated minority species. The angular momentum drive is mainly due to the rf-induced radial minority current. The return current by the bulk plasma gives an equal and opposite rotation drive on the bulk. Using moment equations and a small banana width approximation, the JxB drive was evaluated for the bulk plasma. Quite remarkably, although collisions are included, the net rotation drive is due to a term which can be obtained by neglecting collisions. (c) 2000 American Institute of Physics
Nonlinear interaction and wave breaking with a submerged porous structure
Hsieh, Chih-Min; Sau, Amalendu; Hwang, Robert R.; Yang, W. C.
2016-12-01
Numerical simulations are performed to investigate interactive velocity, streamline, turbulent kinetic energy, and vorticity perturbations in the near-field of a submerged offshore porous triangular structure, as Stokes waves of different heights pass through. The wave-structure interaction and free-surface breaking for the investigated flow situations are established based on solutions of 2D Reynolds Averaged Navier-Stokes equations in a Cartesian grid in combination with K-ɛ turbulent closure and the volume of fluid methodology. The accuracy and stability of the adopted model are ascertained by extensive comparisons of computed data with the existing experimental and theoretical findings and through efficient predictions of the internal physical kinetics. Simulations unfold "clockwise" and "anticlockwise" rotation of fluid below the trough and the crest of the viscous waves, and the penetrated wave energy creates systematic flow perturbation in the porous body. The interfacial growths of the turbulent kinetic energy and the vorticity appear phenomenal, around the apex of the immersed structure, and enhanced significantly following wave breaking. Different values of porosity parameter and two non-porous cases have been examined in combination with varied incident wave height to reveal/analyze the nonlinear flow behavior in regard to local spectral amplification and phase-plane signatures. The evolution of leading harmonics of the undulating free-surface and the vertical velocity exhibits dominating roles of the first and the second modes in inducing the nonlinearity in the post-breaking near-field that penetrates well below the surface layer. The study further suggests the existence of a critical porosity that can substantially enhance the wave-shoaling and interface breaking.
Simpson, Harry Jay
Two mechanisms of sound interacting with sound are experimentally and theoretically investigated. Ultrasonic four-wave mixing in a dilute particle suspension, analogous to optical four-wave mixing in photorefractive materials, involves the interaction of three ultrasonic wavefields that produces a fourth scattered wavefield. The experimental configuration consists of two ultrasonic (800 kHz) pump waves that are used to produce a grating in a suspension of 25 μm diameter polymer particles in salt water. The pump waves are counter-propagating, which form a standing wavefield in the suspension and the less compressible particles are attracted to the pressure nodes in response to the time averaged radiation pressure. A higher frequency (2-10 MHz) ultrasonic wavefield is used to probe the resulting grating. The ultrasonic Bragg scattering is then measured. The scattering depends strongly on the response to the pump wave and is an unusual class of acoustical nonlinearity. Investigation of very small amplitude gratings are done by studying the temporal response of the Bragg scattering to a sudden turn on of a moderate amplitude pump wavefield in a previously homogeneous particle suspension. The Bragg scattering has been verified experimentally and is modeled for early-time grating formations using a sinusoidal grating. The larger amplitude gratings are studied in equilibrium and are modeled using an Epstein layer approximation. Ultrasonic three-wave mixing at a free surface involves the interaction of a high amplitude 400 kHz plane wavefield incident at 33^circ on a water-air interface with a normally incident high frequency (4.6 MHz) focused wavefield. The 400 kHz "pump" wavefield reflects from the surface and produces an oscillating surface displacement that forms a local traveling phase grating. Simultaneously the 4.6 MHz "probe" wavefield is reflected from the free surface. The grating scatters the focused probe wavefield and produces (or contributes to) spatially
Toward a Strongly Interacting Scalar Higgs Particle
International Nuclear Information System (INIS)
Shalaby, Abouzeid M.; El-Houssieny, M.
2008-01-01
We calculate the vacuum energy of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 scalar field theory. Rather than the corresponding Hermitian theory and due to the asymptotic freedom property of the theory, the vacuum energy does not blow up for large energy scales which is a good sign to solve the hierarchy problem when using this model to break the U(1)xSU(2) symmetry in the standard model. The theory is strongly interacting and in fact, all the dimensionful parameters in the theory like mass and energy are finite even for very high energy scales. Moreover, relative to the vacuum energy for the Hermitian φ 4 theory, the vacuum energy of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 theory is tiny, which is a good sign toward the solution of the cosmological constant problem. Remarkably, these features of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 scalar field theory make it very plausible to be employed as a Higgs mechanism in the standard model instead of the problematic Hermitian Higgs mechanism
In- and outbound spreading of a free-particle s-wave
DEFF Research Database (Denmark)
Bialynicki-Birula, i.; Cirone, M. A.; Dahl, Jens Peder
2002-01-01
We show that a free quantum particle in two dimensions with zero angular momentum (s wave) in the form of a ring-shaped wave packet feels an attraction towards the center of the ring, leading first to a contraction followed by an expansion. An experiment to demonstrate this effect is also outlined....
Configuration interaction wave functions: A seniority number approach
International Nuclear Information System (INIS)
Alcoba, Diego R.; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo E.; Oña, Ofelia B.
2014-01-01
This work deals with the configuration interaction method when an N-electron Hamiltonian is projected on Slater determinants which are classified according to their seniority number values. We study the spin features of the wave functions and the size of the matrices required to formulate states of any spin symmetry within this treatment. Correlation energies associated with the wave functions arising from the seniority-based configuration interaction procedure are determined for three types of molecular orbital basis: canonical molecular orbitals, natural orbitals, and the orbitals resulting from minimizing the expectation value of the N-electron seniority number operator. The performance of these bases is analyzed by means of numerical results obtained from selected N-electron systems of several spin symmetries. The comparison of the results highlights the efficiency of the molecular orbital basis which minimizes the mean value of the seniority number for a state, yielding energy values closer to those provided by the full configuration interaction procedure
Configuration interaction wave functions: A seniority number approach
Energy Technology Data Exchange (ETDEWEB)
Alcoba, Diego R. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Física de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Torre, Alicia; Lain, Luis, E-mail: qfplapel@lg.ehu.es [Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, E-48080 Bilbao (Spain); Massaccesi, Gustavo E. [Departamento de Ciencias Exactas, Ciclo Básico Común, Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Oña, Ofelia B. [Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Universidad Nacional de La Plata, CCT La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Diag. 113 y 64 (S/N), Sucursal 4, CC 16, 1900 La Plata (Argentina)
2014-06-21
This work deals with the configuration interaction method when an N-electron Hamiltonian is projected on Slater determinants which are classified according to their seniority number values. We study the spin features of the wave functions and the size of the matrices required to formulate states of any spin symmetry within this treatment. Correlation energies associated with the wave functions arising from the seniority-based configuration interaction procedure are determined for three types of molecular orbital basis: canonical molecular orbitals, natural orbitals, and the orbitals resulting from minimizing the expectation value of the N-electron seniority number operator. The performance of these bases is analyzed by means of numerical results obtained from selected N-electron systems of several spin symmetries. The comparison of the results highlights the efficiency of the molecular orbital basis which minimizes the mean value of the seniority number for a state, yielding energy values closer to those provided by the full configuration interaction procedure.
Transient bimodality in interacting particle systems
International Nuclear Information System (INIS)
Calderoni, P.; Pellegrinotti, A.; Presutti, E.; Vares, M.E.
1989-01-01
The authors consider a system of spins which have values ± 1 and evolve according to a jump Markov process whose generator is the sum of two generators, one describing a spin-flip Glauber process, the other a Kawasaki (stirring) evolution. It was proven elsewhere that if the Kawasaki dynamics is speeded up by a factor var-epsilon -2 , then, in the limit var-epsilon → 0 (continuum limit), propagation of chaos holds and the local magnetization solves a reaction-diffusion equation. They choose the parameters of the Glauber interaction so that the potential of the reaction term in the reaction-diffusion equation is a double-well potential with quartic maximum at the origin. They assume further that for each var-epsilon the system is in a finite interval of Z with var-epsilon -1 sites and periodic boundary conditions. They specify the initial measure as the product measure with 0 spin average, thus obtaining, in the continuum limit, a constant magnetic profile equal to 0, which is a stationary unstable solution to the reaction-diffusion equation. They prove that at times of the order var-epsilon -1/2 propagation of chaos does not hold any more and, in the limit as var-epsilon → 0, the state becomes a nontrivial superposition of Bernoulli measures with parameters corresponding to the minima of the reaction potential. The coefficients of such a superposition depend on time (on the scale var-epsilon -1/2 ) and at large times (on this scale) the coefficient of the term corresponding to the initial magnetization vanishes (transient bimodality). This differs from what was observed by De Masi, Presutti, and Vares, who considered a reaction potential with quadratic maximum and no bimodal effect was seen, as predicted by Broggi, Lugiato, and Colombo
Two-dimensional flow characteristics of wave interactions with a free-rolling rectangular structure
Energy Technology Data Exchange (ETDEWEB)
Kwang Hyo Jung; Kuang-An Chang [Texas A and M University, College Station, TX (United States). Dept. of Civil Engineering; Huang, E.T. [Naval Facilities Engineering Service Center, Port Hueneme, CA (United States). Amphibious System Div.
2005-01-01
This paper presents laboratory observations of flow characteristics for regular waves passing a rectangular structure in a two-dimensional wave tank. The structure with a draft one-half of its height was hinged at the center of gravity and free to roll (one degree of freedom) by waves. Particle image velocimetry (PIV) was used to measure the velocity field in the vicinity of the structure. The mean velocity and turbulence properties were obtained by phase-averaging the PIV velocity maps from repeated test runs. Since the viscous damping (also called the eddy making damping) in a vortical flow affects the roll motion of a blunt body, the quantitative flow pattern was represented to elucidate the coupled interactions between the body motion and the waves. Additionally, the turbulence properties including the turbulence length scale and the turbulent kinetic energy budget were investigated to characterize the interactions. The results show that vortices were generated near the structure corners at locations opposing to that of the roll damping effect for waves with a period longer than the roll natural period of the structure. (Author)
Interactions of casein micelles with calcium phosphate particles.
Tercinier, Lucile; Ye, Aiqian; Anema, Skelte G; Singh, Anne; Singh, Harjinder
2014-06-25
Insoluble calcium phosphate particles, such as hydroxyapatite (HA), are often used in calcium-fortified milks as they are considered to be chemically unreactive. However, this study showed that there was an interaction between the casein micelles in milk and HA particles. The caseins in milk were shown to bind to the HA particles, with the relative proportions of bound β-casein, αS-casein, and κ-casein different from the proportions of the individual caseins present in milk. Transmission electron microscopy showed no evidence of intact casein micelles on the surface of the HA particles, which suggested that the casein micelles dissociated either before or during binding. The HA particles behaved as ion chelators, with the ability to bind the ions contained in the milk serum phase. Consequently, the depletion of the serum minerals disrupted the milk mineral equilibrium, resulting in dissociation of the casein micelles in milk.
Multi-directional random wave interaction with an array of cylinders
DEFF Research Database (Denmark)
Ji, Xinran; Liu, Shuxue; Bingham, Harry B.
2015-01-01
Based on the linear theory of wave interaction with an array of circular bottom-mounted vertical cylinders, systematic calculations are made to investigate the effects of the wave directionality on wave loads in short-crested seas. The multi-directional waves are specified using a discrete form...... of the Mitsuyasu-type spreading function. The time series of multi-directional wave loads, including both the wave run-up and wave force, can be simulated. The effect of wave directionality on the wave run-up and wave loading on the cylinders is investigated. For multi-directional waves, as the distribution...
To the complete integrability of long-wave short-wave interaction equations
International Nuclear Information System (INIS)
Roy Chowdhury, A.; Chanda, P.K.
1984-10-01
We show that the non-linear partial differential equations governing the interaction of long and short waves are completely integrable. The methodology we use is that of Ablowitz et al. though in the last section of our paper we have discussed the problem also in the light of the procedure due to Weiss et al. and have obtained a Baecklund transformation. (author)
International Nuclear Information System (INIS)
Hwang, D.Q.; Horton, R.D.; Evans, R.
1995-01-01
The alpha particle population from fusion reactions in a DT tokamak reactor can have dramatic effects on the pressure profiles, energetic particle confinement, and the overall stability of the plasma; thus leading to important design consideration of a fusion reactor based on the tokamak concept. In order to fully understand the effects of the alpha population, a non-invasive diagnostic technique suitable for use in a reacting plasma environment needs to be developed to map out both the spatial and velocity distribution of the alphas. The proposed experimental goals for the eventual demonstration of LH wave interaction with a fast ion population is given in the reduced 3 year plan in table 1. At present time the authors are approaching the 8th month in their first year of this project. Up to now, their main effort has been concentrated in the operation of the two beat wave sources in burst mode. The second priority in the experimental project is the probe diagnostics and computer aided data acquisition system. The progress made so far is given, and they are ready to perform the beat-wave generated lower hybrid wave experiment. Some theoretical calculation had been reported at APS meetings. More refined theoretical models are being constructed in collaboration with Drs. J. Rogers and E. Valeo at PPPL
High energy particle acceleration by relativistic plasma waves
International Nuclear Information System (INIS)
Amiranoff, F.; Jacquet, F.; Mora, P.; Matthieussent, G.
1991-01-01
Accelerating schemes using plasmas, lasers or electron beams are proposed and compared to electron bunches in dielectric media or laser propagation through a slow wave structure made of liquid droplets. (L.C.J.A.). 33 refs, 20 figs
Search for a particle with a long interaction length
International Nuclear Information System (INIS)
Barrowes, S.C.; Huggett, R.W.; Jones, W.V.; Levit, L.B.; Porter, L.G.
1975-01-01
A search has been carried out for a long-lived particle having an interaction length lambdasub(m) = 300 to 2,000 cm -2 in air. Such a particle, called the mandela, has been proposed by the Leeds group to explain an anomalous energy spectrum of particles observed near sea level with a shallow spectrometer. Data taken at mountain altitude with a deep spectrometer has been examined for compatibility with the existence of the mandela. Although the data tend to favor the mandela hypothesis the results are not conclusive and appear to be explainable by conventional means. (orig.) [de
Particle-turbulence interaction; Partikkelitihentymien ja turbulenssin vuorovaikutus
Energy Technology Data Exchange (ETDEWEB)
Karvinen, R.; Savolainen, K. [Tampere Univ. of Technology (Finland). Energy and Process Technology
1997-10-01
In this work the interaction between solid particles and turbulence of the carrier fluid in two-phase flow is studied. The aim of the study is to find out prediction methods for the interaction of particles and fluid turbulence. Accurate measured results are needed in order to develop numerical simulations. There are very few good experimental data sets concerning the particulate matter and its effect on the gas turbulence. Turbulence of the gas phase in a vertical, dilute gas-particle pipe flow has been measured with the laser-Doppler anemometer in Tampere University of Technology. Special attention was paid to different components of the fluctuating velocity. Numerical simulations were done with the Phoenics-code in which the models of two-phase flows suggested in the literature were implemented. It has been observed that the particulate phase increases the rate of anisotropy of the fluid turbulence. It seems to be so that small rigid particles increase the intensity of the axial and decrease the intensity of the radial component in a vertical pipe flow. The change of the total kinetic energy of turbulence obviously depends on the particle size. In the case of 150 ,{mu} spherical glass particles flowing upwards with air, it seems to be slightly positive near the centerline of the pipe. This observation, i.e. the particles decrease turbulence in the radial direction, is very important; because mass and heat transfer in flows is strongly dependent on the component of fluctuating velocity perpendicular to the main flow direction
Inter-particle and interfacial interaction of magnetic nanoparticles
International Nuclear Information System (INIS)
Bae, Che Jin; Hwang, Yosun; Park, Jongnam; An, Kwangjin; Lee, Youjin; Lee, Jinwoo; Hyeon, Taeghwan; Park, J.-G.
2007-01-01
In order to understand inter-particle as well as interfacial interaction of magnetic nanoparticles, we have prepared several Fe 3 O 4 nanoparticles in the ranges from 3 to 50 nm. These nanoparticles are particularly well characterized in terms of size distribution with a standard deviation (σ) in size less than 0.4 nm. We investigated the inter-particle interaction by measuring the magnetic properties of the nanoparticles while controlling inter-particle distances by diluting the samples with solvents. According to this study, blocking temperatures dropped by 8-17 K with increasing the inter-particle distances from a few nm to 140 nm while the overall shape and qualitative behavior of the magnetization remain unchanged. It implies that most features observed in the magnetic properties of the nanoparticles are due to the intrinsic properties of the nanoparticles, not due to the inter-particle interaction. We then examined possible interfacial magnetic interaction in the core-shell structure of our Fe 3 O 4 nanoparticles
Remote recoil: a new wave mean interaction effect
Bühler, Oliver; McIntyre, Michael E.
2003-10-01
We present a theoretical study of a fundamentally new wave mean or wave vortex interaction effect able to force persistent, cumulative change in mean flows in the absence of wave breaking or other kinds of wave dissipation. It is associated with the refraction of non-dissipating waves by inhomogeneous mean (vortical) flows. The effect is studied in detail in the simplest relevant model, the two-dimensional compressible flow equations with a generic polytropic equation of state. This includes the usual shallow-water equations as a special case. The refraction of a narrow, slowly varying wavetrain of small-amplitude gravity or sound waves obliquely incident on a single weak (low Froude or Mach number) vortex is studied in detail. It is shown that, concomitant with the changes in the waves' pseudomomentum due to the refraction, there is an equal and opposite recoil force that is felt, in effect, by the vortex core. This effective force is called a ‘remote recoil’ to stress that there is no need for the vortex core and wavetrain to overlap in physical space. There is an accompanying ‘far-field recoil’ that is still more remote, as in classical vortex-impulse problems. The remote-recoil effects are studied perturbatively using the wave amplitude and vortex weakness as small parameters. The nature of the remote recoil is demonstrated in various set-ups with wavetrains of finite or infinite length. The effective recoil force {bm R}_V on the vortex core is given by an expression resembling the classical Magnus force felt by moving cylinders with circulation. In the case of wavetrains of infinite length, an explicit formula for the scattering angle theta_* of waves passing a vortex at a distance is derived correct to second order in Froude or Mach number. To this order {bm R}_V {~} theta_*. The formula is cross-checked against numerical integrations of the ray-tracing equations. This work is part of an ongoing study of internal-gravity-wave dynamics in the
International Nuclear Information System (INIS)
Oscarsson, T.E.; Roennmark, K.G.
1990-01-01
In this paper the authors present an investigation of low-frequency waves observed on auroral field lines below the acceleration region by the Swedish satellite Viking. The measured frequency spectra are peaked at half the local proton gyrofrequency, and the waves are observed in close connection with precipitating electrons. In order to obtain information about the distribution of wave energy in wave vector space, they reconstruct the wave distribution function (WDF) from observed spectral densities. They use a new scheme that allows them to reconstruct simultaneously the WDF over a broad frequency band. The method also makes it possible to take into account available particle observations as well as Doppler shifts caused by the relative motion between the plasma and the satellite. The distribution of energy in wave vector space suggested by the reconstructed WDF is found to be consistent with what is expected from a plasma instability driven by the observed precipitating electrons. Furthermore, by using UV images obtained on Viking, they demonstrate that the wave propagation directions indicated by the reconstructed WDFs are consistent with a simple model of the presumed wave source in the electron precipitation region
Numerical Computation of Wave-Plasma Interactions in Multi-Dimensional Systems
International Nuclear Information System (INIS)
D. A. D'Ippolito; J. R. Myra
2005-01-01
This project studied two kinds of nonlinear interactions between ion cyclotron range of frequency waves and fusion plasmas. A wavelet technique was also developed for analyzing the complex wave fields produced by wave propagation codes
Artemyev, Anton V.; Neishtadt, Anatoly I.; Vasiliev, Alexei A.
2018-04-01
Accurately modelling and forecasting of the dynamics of the Earth's radiation belts with the available computer resources represents an important challenge that still requires significant advances in the theoretical plasma physics field of wave-particle resonant interaction. Energetic electron acceleration or scattering into the Earth's atmosphere are essentially controlled by their resonances with electromagnetic whistler mode waves. The quasi-linear diffusion equation describes well this resonant interaction for low intensity waves. During the last decade, however, spacecraft observations in the radiation belts have revealed a large number of whistler mode waves with sufficiently high intensity to interact with electrons in the nonlinear regime. A kinetic equation including such nonlinear wave-particle interactions and describing the long-term evolution of the electron distribution is the focus of the present paper. Using the Hamiltonian theory of resonant phenomena, we describe individual electron resonance with an intense coherent whistler mode wave. The derived characteristics of such a resonance are incorporated into a generalized kinetic equation which includes non-local transport in energy space. This transport is produced by resonant electron trapping and nonlinear acceleration. We describe the methods allowing the construction of nonlinear resonant terms in the kinetic equation and discuss possible applications of this equation.
Stochasticity of phase trajectory of a charged particle in a plasma wave
International Nuclear Information System (INIS)
Murakami, Akihiko; Nomura, Yasuyuki; Momota, Hiromu.
1980-06-01
Stochastic behavior of charged particles in finite amplitude plasma waves is examined by means of particle simulations under the condition that Chirikov's criterion is broken down. The process of growint the stochastic region is clarified and accordingly the width of the stochastic region is discussed. Discussions on the effects of higher order resonances are also presented. (author)
Simulation and scaling analysis of a spherical particle-laden blast wave
Ling, Y.; Balachandar, S.
2018-05-01
A spherical particle-laden blast wave, generated by a sudden release of a sphere of compressed gas-particle mixture, is investigated by numerical simulation. The present problem is a multiphase extension of the classic finite-source spherical blast-wave problem. The gas-particle flow can be fully determined by the initial radius of the spherical mixture and the properties of gas and particles. In many applications, the key dimensionless parameters, such as the initial pressure and density ratios between the compressed gas and the ambient air, can vary over a wide range. Parametric studies are thus performed to investigate the effects of these parameters on the characteristic time and spatial scales of the particle-laden blast wave, such as the maximum radius the contact discontinuity can reach and the time when the particle front crosses the contact discontinuity. A scaling analysis is conducted to establish a scaling relation between the characteristic scales and the controlling parameters. A length scale that incorporates the initial pressure ratio is proposed, which is able to approximately collapse the simulation results for the gas flow for a wide range of initial pressure ratios. This indicates that an approximate similarity solution for a spherical blast wave exists, which is independent of the initial pressure ratio. The approximate scaling is also valid for the particle front if the particles are small and closely follow the surrounding gas.
Simulation and scaling analysis of a spherical particle-laden blast wave
Ling, Y.; Balachandar, S.
2018-02-01
A spherical particle-laden blast wave, generated by a sudden release of a sphere of compressed gas-particle mixture, is investigated by numerical simulation. The present problem is a multiphase extension of the classic finite-source spherical blast-wave problem. The gas-particle flow can be fully determined by the initial radius of the spherical mixture and the properties of gas and particles. In many applications, the key dimensionless parameters, such as the initial pressure and density ratios between the compressed gas and the ambient air, can vary over a wide range. Parametric studies are thus performed to investigate the effects of these parameters on the characteristic time and spatial scales of the particle-laden blast wave, such as the maximum radius the contact discontinuity can reach and the time when the particle front crosses the contact discontinuity. A scaling analysis is conducted to establish a scaling relation between the characteristic scales and the controlling parameters. A length scale that incorporates the initial pressure ratio is proposed, which is able to approximately collapse the simulation results for the gas flow for a wide range of initial pressure ratios. This indicates that an approximate similarity solution for a spherical blast wave exists, which is independent of the initial pressure ratio. The approximate scaling is also valid for the particle front if the particles are small and closely follow the surrounding gas.
On dynamics of resonant charged particles in cyclotron electromagnetic wave field
International Nuclear Information System (INIS)
Shyutte, N.M.; Izhovkina, N.I.
1989-01-01
The model of time and spatial separation of resonance and nonresonance particles with quasimonochromatic wave packets during their propagation in the magnetosphere is presented. In regions with elevated geomagnetic field gradients and.or in waveguide channels such separation can result in diffusion increase of resonance particles by the pitch angle and create ''little peaks'' in the distribution function tail
Dirac particle in a plane wave field and the semi-classical approximation
Energy Technology Data Exchange (ETDEWEB)
Bourouaine, S. [Department of Physics, Faculty of Sciences, Mentouri University, Constantine (Algeria)
2005-04-01
In this paper we investigate the influence of photon represented by plane wave field on Dirac particle in the context of path integral approach given by Fradkin and Gitman formalism. In our case, although the action relative to Dirac particle in plane wave field seems to be non quadratic, the result obtained by semi-classical approach is the same as that found by an exact calculation. Hence; when we add the plane wave field to any quadratic actions related to Fradkin and Gitman approach, the total action behaves like quadratic. (Abstract Copyright [2005], Wiley Periodicals, Inc.)
Dirac particle in a plane wave field and the semi-classical approximation
International Nuclear Information System (INIS)
Bourouaine, S.
2005-01-01
In this paper we investigate the influence of photon represented by plane wave field on Dirac particle in the context of path integral approach given by Fradkin and Gitman formalism. In our case, although the action relative to Dirac particle in plane wave field seems to be non quadratic, the result obtained by semi-classical approach is the same as that found by an exact calculation. Hence; when we add the plane wave field to any quadratic actions related to Fradkin and Gitman approach, the total action behaves like quadratic. (Abstract Copyright [2005], Wiley Periodicals, Inc.)
Measurement of Anisotropic Particle Interactions with Nonuniform ac Electric Fields.
Rupp, Bradley; Torres-Díaz, Isaac; Hua, Xiaoqing; Bevan, Michael A
2018-02-20
Optical microscopy measurements are reported for single anisotropic polymer particles interacting with nonuniform ac electric fields. The present study is limited to conditions where gravity confines particles with their long axis parallel to the substrate such that particles can be treated using quasi-2D analysis. Field parameters are investigated that result in particles residing at either electric field maxima or minima and with long axes oriented either parallel or perpendicular to the electric field direction. By nonintrusively observing thermally sampled positions and orientations at different field frequencies and amplitudes, a Boltzmann inversion of the time-averaged probability of states yields kT-scale energy landscapes (including dipole-field, particle-substrate, and gravitational potentials). The measured energy landscapes show agreement with theoretical potentials using particle conductivity as the sole adjustable material property. Understanding anisotropic particle-field energy landscapes vs field parameters enables quantitative control of local forces and torques on single anisotropic particles to manipulate their position and orientation within nonuniform fields.
Electrostatic Charging and Particle Interactions in Microscopic Insulating Grains
Lee, Victor
In this thesis, we experimentally investigate the electrostatic charging as well as the particle interactions in microscopic insulating grains. First, by tracking individual grains accelerated in an electric field, we quantitatively demonstrate that tribocharging of same-material grains depends on particle size. Large grains tend to charge positively, and small ones tend to charge negatively. Theories based on the transfer of trapped electrons can explain this tendency but have not been validated. Here we show that the number of trapped electrons, measured independently by a thermoluminescence technique, is orders of magnitude too small to be responsible for the amount of charge transferred. This result reveals that trapped electrons are not responsible for same-material tribocharging of dielectric particles. Second, same-material tribocharging in grains can result in important long-range electrostatic interactions. However, how these electrostatic interactions contribute to particle clustering remains elusive, primarily due to the lack of direct, detailed observations. Using a high-speed camera that falls with a stream charged grains, we observe for the first time how charged grains can undergo attractive as well as repulsive Kepler-like orbits. Charged particles can be captured in their mutual electrostatic potential and form clusters via multiple bounces. Dielectric polarization effects are directly observed, which lead to additional attractive forces and stabilize "molecule-like" arrangements of charged particles. Third, we have developed a new method to study the charge transfer of microscopic particles based on acoustic levitation techniques. This method allows us to narrow the complex problem of many-particle charging down to precise charge measurements of a single sub-millimeter particle colliding with a target plate. By simply attaching nonpolar groups onto glass surfaces, we show that the contact charging of a particle is highly dependent on
A 20-Year High-Resolution Wave Resource Assessment of Japan with Wave-Current Interactions
Webb, A.; Waseda, T.; Kiyomatsu, K.
2016-02-01
Energy harvested from surface ocean waves and tidal currents has the potential to be a significant source of green energy, particularly for countries with extensive coastlines such as Japan. As part of a larger marine renewable energy project*, The University of Tokyo (in cooperation with JAMSTEC) has conducted a state-of-the-art wave resource assessment (with uncertainty estimates) to assist with wave generator site identification and construction in Japan. This assessment will be publicly available and is based on a large-scale NOAA WAVEWATCH III (version 4.18) simulation using NCEP and JAMSTEC forcings. It includes several key components to improve model skill: a 20-year simulation to reduce aleatory uncertainty, a four-nested-layer approach to resolve a 1 km shoreline, and finite-depth and current effects included in all wave power density calculations. This latter component is particularly important for regions near strong currents such as the Kuroshio. Here, we will analyze the different wave power density equations, discuss the model setup, and present results from the 20-year assessment (with a focus on the role of wave-current interactions). Time permitting, a comparison will also be made with simulations using JMA MSM 5 km winds. *New Energy and Industrial Technology Development Organization (NEDO): "Research on the Framework and Infrastructure of Marine Renewable Energy; an Energy Potential Assessment"
Interaction mechanisms between ceramic particles and atomized metallic droplets
Wu, Yue; Lavernia, Enrique J.
1992-10-01
The present study was undertaken to provide insight into the dynamic interactions that occur when ceramic particles are placed in intimate contact with a metallic matrix undergoing a phase change. To that effect, Al-4 wt pct Si/SiCp composite droplets were synthesized using a spray atomization and coinjection approach, and their solidification microstructures were studied both qualitatively and quantitatively. The present results show that SiC particles (SiCp) were incor- porated into the matrix and that the extent of incorporation depends on the solidification con- dition of the droplets at the moment of SiC particle injection. Two factors were found to affect the distribution and volume fraction of SiC particles in droplets: the penetration of particles into droplets and the entrapment and/or rejection of particles by the solidification front. First, during coinjection, particles collide with the atomized droplets with three possible results: they may penetrate the droplets, adhere to the droplet surface, or bounce back after impact. The extent of penetration of SiC particles into droplets was noted to depend on the kinetic energy of the particles and the magnitude of the surface energy change in the droplets that occurs upon impact. In liquid droplets, the extent of penetration of SiC particles was shown to depend on the changes in surface energy, ΔEs, experienced by the droplets. Accordingly, large SiC particles encoun- tered more resistance to penetration relative to small ones. In solid droplets, the penetration of SiC particles was correlated with the dynamic pressure exerted by the SiC particles on the droplets during impact and the depth of the ensuing crater. The results showed that no pene- tration was possible in such droplets. Second, once SiC particles have penetrated droplets, their final location in the microstructure is governed by their interactions with the solidification front. As a result of these interactions, both entrapment and rejection of
Particle simulation of intense electron cyclotron heating and beat-wave current drive
International Nuclear Information System (INIS)
Cohen, B.I.
1987-01-01
High-power free-electron lasers make new methods possible for heating plasmas and driving current in toroidal plasmas with electromagnetic waves. We have undertaken particle simulation studies with one and two dimensional, relativistic particle simulation codes of intense pulsed electron cyclotron heating and beat-wave current drive. The particle simulation methods here are conventional: the algorithms are time-centered, second-order-accurate, explicit, leap-frog difference schemes. The use of conventional methods restricts the range of space and time scales to be relatively compact in the problems addressed. Nevertheless, experimentally relevant simulations have been performed. 10 refs., 2 figs
The GRA beam-splitter experiments and wave-particle duality of light
International Nuclear Information System (INIS)
Kaloyerou, P.N.
2005-01-01
Full text: Grangier, Roger and Aspect (GRA) performed a beam-splitter experiment to demonstrate particle behaviour of light and a Mach-Zehnder interferometer experiment to demonstrate wave behaviour of light. The distinguishing feature of these experiments is the use of a gating system to produce near ideal single photon states. With the demonstration of both wave and particle behaviour (in the two mutually exclusive experiments) they claim to have demonstrated the dual wave-particle behaviour of light. The demonstration of the wave behaviour of light is not in dispute. But, we want to demonstrate, contrary to the claims of GRA, that their beam-splitter experiment does not conclusively confirm the particle behaviour of light, and hence does not demonstrate particle-wave duality. Our demonstration consists of providing a detailed model, not involving particles, of GRA's 'which-path' experiment. The model uses the causal interpretation of quantum fields. We will also give a brief outline a model for the second 'interference' GRA experiment. (author)
Asymptotic approach for the nonlinear equatorial long wave interactions
International Nuclear Information System (INIS)
Ramirez Gutierrez, Enver; Silva Dias, Pedro L; Raupp, Carlos
2011-01-01
In the present work we use an asymptotic approach to obtain the long wave equations. The shallow water equation is put as a function of an external parameter that is a measure of both the spatial scales anisotropy and the fast to slow time ratio. The values given to the external parameters are consistent with those computed using typical values of the perturbations in tropical dynamics. Asymptotically, the model converge toward the long wave model. Thus, it is possible to go toward the long wave approximation through intermediate realizable states. With this approach, the resonant nonlinear wave interactions are studied. To simplify, the reduced dynamics of a single resonant triad is used for some selected equatorial trios. It was verified by both theoretical and numerical results that the nonlinear energy exchange period increases smoothly as we move toward the long wave approach. The magnitude of the energy exchanges is also modified, but in this case depends on the particular triad used and also on the initial energy partition among the triad components. Some implications of the results for the tropical dynamics are discussed. In particular, we discuss the implications of the results for El Nino and the Madden-Julian in connection with other scales of time and spatial variability.
Monte Carlo simulations of interacting particle mixtures in ratchet potentials
International Nuclear Information System (INIS)
Fendrik, A J; Romanelli, L
2012-01-01
There are different models of devices for achieving a separation of mixtures of particles by using the ratchet effect. On the other hand, it has been proposed that one could also control the separation by means of appropriate interactions. Through Monte Carlo simulations, we show that inclusion of simple interactions leads to a decrease of the ratchet effect and therefore also a separation of the mixtures.
International Nuclear Information System (INIS)
Khalil, Sh.M.; El-Sherif, N.; El-Siragy, N.M.; Tanta Univ.; El-Naggar, I.A.; Alexandria Univ.
1985-01-01
Investigation is made for nonlinear interaction between incident radiation and a surface wave in a magnetized plasma layer. Both interacting waves are of P polarization. The generated currents and fields at combination frequencies are obtained analytically. Unlike the S-polarized interacting waves, the magnetic field affects the fundamental waves and leads to an amplification of generated waves when their frequencies approach the cyclotron frequency. (author)
Particle Swarm Optimization With Interswarm Interactive Learning Strategy.
Qin, Quande; Cheng, Shi; Zhang, Qingyu; Li, Li; Shi, Yuhui
2016-10-01
The learning strategy in the canonical particle swarm optimization (PSO) algorithm is often blamed for being the primary reason for loss of diversity. Population diversity maintenance is crucial for preventing particles from being stuck into local optima. In this paper, we present an improved PSO algorithm with an interswarm interactive learning strategy (IILPSO) by overcoming the drawbacks of the canonical PSO algorithm's learning strategy. IILPSO is inspired by the phenomenon in human society that the interactive learning behavior takes place among different groups. Particles in IILPSO are divided into two swarms. The interswarm interactive learning (IIL) behavior is triggered when the best particle's fitness value of both the swarms does not improve for a certain number of iterations. According to the best particle's fitness value of each swarm, the softmax method and roulette method are used to determine the roles of the two swarms as the learning swarm and the learned swarm. In addition, the velocity mutation operator and global best vibration strategy are used to improve the algorithm's global search capability. The IIL strategy is applied to PSO with global star and local ring structures, which are termed as IILPSO-G and IILPSO-L algorithm, respectively. Numerical experiments are conducted to compare the proposed algorithms with eight popular PSO variants. From the experimental results, IILPSO demonstrates the good performance in terms of solution accuracy, convergence speed, and reliability. Finally, the variations of the population diversity in the entire search process provide an explanation why IILPSO performs effectively.
Relativistic wave equations for particles in electromagnetic fields
International Nuclear Information System (INIS)
Good, R.H. Jr.
1989-01-01
A new type of generalization of the Dirac equation of higher spin particles and antiparticles is given, in case only the terms proportional to the external fields need to be retained. copyright 1989 Academic Press, Inc
DEFF Research Database (Denmark)
Rasmussen, Anders Rønne; Sørensen, Mads Peter; Gaididei, Yuri Borisovich
2011-01-01
A wave equation including nonlinear terms up to the second order for a thermoviscous Newtonian fluid is proposed. In the lossless case this equation results from an expansion to third order of the Lagrangian for the fundamental non-dissipative fluid dynamical equations. Thus it preserves the Hami...... is proposed. The dynamics of the rarefaction wave is approximated by a collective coordinate approach in the energy balance equation. © 2010 Springer Science+Business Media B.V.......A wave equation including nonlinear terms up to the second order for a thermoviscous Newtonian fluid is proposed. In the lossless case this equation results from an expansion to third order of the Lagrangian for the fundamental non-dissipative fluid dynamical equations. Thus it preserves...... the Hamiltonian structure, in contrast to the Kuznetsov equation, a model often used in nonlinear acoustics. An exact traveling wave front solution is derived from a generalized traveling wave assumption for the velocity potential. Numerical studies of the evolution of a number of arbitrary initial conditions...
Interaction of neutral particles with strong laser fields
Energy Technology Data Exchange (ETDEWEB)
Meuren, Sebastian; Keitel, Christoph H.; Di Piazza, Antonino [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)
2013-07-01
Since the invention of the laser in the 1960s the experimentally available field strengths have continuously increased. The current peak intensity record is 2 x 10{sup 22} W/cm{sup 2} and next generation facilities such as ELI, HiPER and XCELS plan to reach even intensities of the order of 10{sup 24} W/cm{sup 2}. Thus, modern laser facilities are a clean source for very strong external electromagnetic fields and promise new and interesting high-energy physics experiments. In particular, strong laser fields could be used to test non-linear effects in quantum field theory. Earlier we have investigated how radiative corrections modify the coupling of a charged particle inside a strong plane-wave electromagnetic background field. However, a charged particle couples already at tree level to electromagnetic radiation. Therefore, we have now analyzed how the coupling between neutral particles and radiation is affected by a very strong plane-wave electromagnetic background field, when loop corrections are taken into account. In particular, the case of neutrinos is discussed.
Simulation of hypersonic shock wave - laminar boundary layer interactions
Kianvashrad, N.; Knight, D.
2017-06-01
The capability of the Navier-Stokes equations with a perfect gas model for simulation of hypersonic shock wave - laminar boundary layer interactions is assessed. The configuration is a hollow cylinder flare. The experimental data were obtained by Calspan-University of Buffalo (CUBRC) for total enthalpies ranging from 5.07 to 21.85 MJ/kg. Comparison of the computed and experimental surface pressure and heat transfer is performed and the computed §ow¦eld structure is analyzed.
Pair interaction of bilayer-coated nanoscopic particles
International Nuclear Information System (INIS)
Qi-Yi, Zhang
2009-01-01
The pair interaction between bilayer membrane-coated nanosized particles has been explored by using the self-consistent field (SCF) theory. The bilayer membranes are composed of amphiphilic polymers. For different system parameters, the pair-interaction free energies are obtained. Particular emphasis is placed on the analysis of a sequence of structural transformations of bilayers on spherical particles, which occur during their approaching processes. For different head fractions of amphiphiles, the asymmetrical morphologies between bilayers on two particles and the inverted micellar intermediates have been found in the membrane fusion pathway. These results can benefit the fabrication of vesicles as encapsulation vectors for drug and gene delivery. (condensed matter: structure, thermal and mechanical properties)
On the relativistic quantum mechanics of two interacting spinless particles
International Nuclear Information System (INIS)
Rizov, V.A.; Sazdjian, H.; Todorov, I.T.
1984-05-01
The L 2 -scalar product ∫ PHI*(x)PSI(x) d 3 x is not appropriate for the space of states describing the center-of-mass relative motion of two relativistic particles whose interaction is given by an energy dependent quasipotential. The problem already appears in the relativistic quantum mechanics of a Klein-Gordon charged particle in an external field. We extend the methods developed for that case to study a two-particle system with an energy independent scalar interaction as well as the relativistic Coulomb problem. We write down a Poincare invariant inner product for which the eigenfunctions corresponding to different energy eigenvalues are orthogonal. We also construct a perturbative expansion for bound-state energy eigenvalues corresponding to an arbitrary energy dependent (quasipotential) correction to an unperturbed Hamiltonian with a known spectrum. The description of observables and transition probabilities for eigenvalue problems with a polynomial dependence on the spectral parameter is also discussed
Conservative interacting particles system with anomalous rate of ergodicity
Brzeźniak, Zdzislaw; Flandoli, Franco; Neklyudov, Misha; Zegarliński, Boguslaw
2010-01-01
We analyze certain conservative interacting particle system and establish ergodicity of the system for a family of invariant measures. Furthermore, we show that convergence rate to equilibrium is exponential. This result is of interest because it presents counterexample to the standard assumption of physicists that conservative system implies polynomial rate of convergence.
Interaction Potential between Parabolic Rotator and an Outside Particle
Directory of Open Access Journals (Sweden)
Dan Wang
2014-01-01
Full Text Available At micro/nanoscale, the interaction potential between parabolic rotator and a particle located outside the rotator is studied on the basis of the negative exponential pair potential 1/Rn between particles. Similar to two-dimensional curved surfaces, we confirm that the potential of the three-dimensional parabolic rotator and outside particle can also be expressed as a unified form of curvatures; that is, it can be written as the function of curvatures. Furthermore, we verify that the driving forces acting on the particle may be induced by the highly curved micro/nano-parabolic rotator. Curvatures and the gradient of curvatures are the essential elements forming the driving forces. Through the idealized numerical experiments, the accuracy of the curvature-based potential is preliminarily proved.
Buoy and Generator Interaction with Ocean Waves: Studies of a Wave Energy Conversion System
Energy Technology Data Exchange (ETDEWEB)
Lindroth, Simon
2011-07-01
On March 13th, 2006, the Div. of Electricity at Uppsala Univ. deployed its first wave energy converter, L1, in the ocean southwest of Lysekil. L1 consisted of a buoy at the surface, connected through a line to a linear generator on the seabed. Since the deployment, continuous investigations of how L1 works in the waves have been conducted, and several additional wave energy converters have been deployed. This thesis is based on ten publications, which focus on different aspects of the interaction between wave, buoy, and generator. In order to evaluate different measurement systems, the motion of the buoy was measured optically and using accelerometers, and compared to measurements of the motion of the movable part of the generator - the translator. These measurements were found to correlate well. Simulations of buoy and translator motion were found to match the measured values. The variation of performance of L1 with changing water levels, wave heights, and spectral shapes was also investigated. Performance is here defined as the ratio of absorbed power to incoming power. It was found that the performance decreases for large wave heights. This is in accordance with the theoretical predictions, since the area for which the stator and the translator overlap decreases for large translator motions. Shifting water levels were predicted to have the same effect, but this could not be seen as clearly. The width of the wave energy spectrum has been proposed by some as a factor that also affects the performance of a wave energy converter, for a set wave height and period. Therefore the relation between performance and several different parameters for spectral width was investigated. It was found that some of the parameters were in fact correlated to performance, but that the correlation was not very strong. As a background on ocean measurements in wave energy, a thorough literature review was conducted. It turns out that the Lysekil project is one of quite few projects that
Superstring interactions in a pp-wave background II
International Nuclear Information System (INIS)
Spradlin, Marcus; Volovich, Anastasia
2003-01-01
In type-IIB light-cone superstring field theory, the cubic interaction has two pieces: a delta-functional overlap and an operator inserted at the interaction point. In this paper we extend our earlier work by computing the matrix elements of this operator in the oscillator basis of pp-wave string theory for all μ p +α '. By evaluating these matrix elements for large μ p +α ', we check a recent conjecture relating matrix elements of the light-cone string field theory hamiltonian (with prefactor) to certain three-point functions of BMN operators in the gauge theory. We also make several predictions for gauge theory. (author)
International Nuclear Information System (INIS)
Wang, Xin; Chen, Yong; Cao, Jianli
2015-01-01
In this paper, we utilize generalized Darboux transformation to study higher-order rogue wave solutions of the three-wave resonant interaction equation, which describes the propagation and mixing of waves with different frequencies in weakly nonlinear dispersive media. A general Nth-order rogue wave solution with two characteristic velocities structural parameters and 3N independent parameters under a determined plane-wave background and a specific parameter condition is derived. As an application, we show that four fundamental rogue waves with fundamental, two kinds of line and quadrilateral patterns, or six fundamental rogue waves with fundamental, triangular, two kinds of quadrilateral and circular patterns can emerge in the second-order rogue waves. Moreover, several important wave characteristics including the maximum values, the corresponding coordinate positions of the humps, and the stability problem for some special higher-order rogue wave solutions such as the fundamental and quadrilateral cases are discussed. (paper)
Advanced computational simulations of water waves interacting with wave energy converters
Pathak, Ashish; Freniere, Cole; Raessi, Mehdi
2017-03-01
Wave energy converter (WEC) devices harness the renewable ocean wave energy and convert it into useful forms of energy, e.g. mechanical or electrical. This paper presents an advanced 3D computational framework to study the interaction between water waves and WEC devices. The computational tool solves the full Navier-Stokes equations and considers all important effects impacting the device performance. To enable large-scale simulations in fast turnaround times, the computational solver was developed in an MPI parallel framework. A fast multigrid preconditioned solver is introduced to solve the computationally expensive pressure Poisson equation. The computational solver was applied to two surface-piercing WEC geometries: bottom-hinged cylinder and flap. Their numerically simulated response was validated against experimental data. Additional simulations were conducted to investigate the applicability of Froude scaling in predicting full-scale WEC response from the model experiments.
Beam-wave interaction in periodic and quasi-periodic structures. 2. ed.
International Nuclear Information System (INIS)
Schaechter, Levi
2011-01-01
The main theme of this book is the interaction of electrons with electromagnetic waves in the presence of periodic and quasi-periodic structures in vacuum, in view of applications in the design and operation of particle accelerators. The first part of the book is concerned with the textbook-like presentation of the basic material, in particular reviewing elementary electromagnetic phenomena and electron dynamics. The second part of the book describes the current models for beam-wave interactions with periodic and quasi-periodic structures. This is the basis for introducing, in the last part of the book, a number of particle and radiation sources that rest on these principles, in particular the free-electron laser, wake-field acceleration schemes and a number of other advanced particle accelerator concepts. This second edition brings this fundamental text up-to-date in view of the enormous advances that have been made over the last decade since the first edition was published. All chapters, as well as the bibliography, have been significantly revised and extended, and the number of end-of-chapter exercises has been further increased to enhance this book's usefulness for teaching specialized graduate courses. (orig.)
The interaction of extreme waves with hull elements
Galiev, Shamil; Flay, Richard
2010-05-01
The problem of the impact of a rogue wave onto a deformable marine structure is formulated in a few publications (see, for example, a short review in http://researchspace.auckland.ac.nz/handle/2292/4474). In this paper the results from numerical and experimental investigations of the effect of cavitation on the deformation of a hull element, loaded by a wall of water, generated by an extreme ocean surface wave are considered. The hull element is modelled as a circular metal plate with the edge of the plate rigidly clamped. The plate surface is much smaller than the surface of the wave front, so that at the initial moment of the interaction, the pressure is constant on the plate surface. At the next instant, because of the plate deformation, axisymmetric loading of the plate occurs. The influences of membrane forces and plastic deformations are ignored, and therefore, the equation of plate motion has the following classical form Eh3(wrrrr+2r -1wrrrr- r-2wrr+r-3wr) = - 121- ν2)[ρhwtt+ δ(r,t)(p+ ρ0a0wt)]. Here w is the plate displacement, subscripts t and rindicate derivatives with respect to time and the radial coordinate, PIC is the plate material density, his the plate thickness, Eis Young's modulus, PIC is Poisson's ratio and p is the pressure of the incident surface wave measured on the wall, PIC is the water density, PIC is the speed of sound in water, and PIC is the normal velocity of the plate. The term PIC takes into account the effect of the deformability of the plate. Obviously, the hull of a vessel is not rigid like a solid wall, but starts to deform and to move. This motion produces a reflected pressure wave, which travels from the hull into the water wave with a magnitude equal to PIC . The normal velocity is positive so the reflected pressure PIC is negative (tensile wave). If the fluid pressure drops below some critical value pk, the wet plate surface separates from the water, and cavitation may be generated. The function δ(r,t) takes into account
Nonlinear theory of diffusive acceleration of particles by shock waves
Energy Technology Data Exchange (ETDEWEB)
Malkov, M.A. [University of California at San Diego, La Jolla, CA (United States)]. E-mail: mmalkov@ucsd.edu; Drury, L. O' C. [Dublin Institute for Advanced Studies, 5 Merrion Square, Dublin 2 (Ireland)
2001-04-01
Among the various acceleration mechanisms which have been suggested as responsible for the nonthermal particle spectra and associated radiation observed in many astrophysical and space physics environments, diffusive shock acceleration appears to be the most successful. We review the current theoretical understanding of this process, from the basic ideas of how a shock energizes a few reactionless particles to the advanced nonlinear approaches treating the shock and accelerated particles as a symbiotic self-organizing system. By means of direct solution of the nonlinear problem we set the limit to the test-particle approximation and demonstrate the fundamental role of nonlinearity in shocks of astrophysical size and lifetime. We study the bifurcation of this system, proceeding from the hydrodynamic to kinetic description under a realistic condition of Bohm diffusivity. We emphasize the importance of collective plasma phenomena for the global flow structure and acceleration efficiency by considering the injection process, an initial stage of acceleration and, the related aspects of the physics of collisionless shocks. We calculate the injection rate for different shock parameters and different species. This, together with differential acceleration resulting from nonlinear large-scale modification, determines the chemical composition of accelerated particles. The review concentrates on theoretical and analytical aspects but our strategic goal is to link the fundamental theoretical ideas with the rapidly growing wealth of observational data. (author)
The Mathematics of Charged Particles interacting with Electromagnetic Fields
DEFF Research Database (Denmark)
Petersen, Kim
In this thesis, we study the mathematics used to describe systems of charged quantum mechanical particles coupled with their classical self-generated electromagnetic field. We prove the existence of a unique local in time solution to the many-body Maxwell-Schrödinger initial value problem expressed...... in Coulomb gauge and we show that the one-body Maxwell-Schrödinger system as well as the related one-body Maxwell-Pauli system both admit travelling wave solutions....
Plasma Interaction and Energetic Particle Dynamics near Callisto
Liuzzo, L.; Simon, S.; Feyerabend, M.; Motschmann, U. M.
2017-12-01
Callisto's magnetic environment is characterized by a complex admixture of induction signals from its conducting subsurface ocean, the interaction of corotating Jovian magnetospheric plasma with the moon's ionosphere and induced dipole, and the non-linear coupling between the effects. In contrast to other Galilean moons, ion gyroradii near Callisto are comparable to its size, requiring a kinetic treatment of the interaction region near the moon. Thus, we apply the hybrid simulation code AIKEF to constrain the competing effects of plasma interaction and induction. We determine their influence on the magnetic field signatures measured by Galileo during various Callisto flybys. We use the magnetic field calculated by the model to investigate energetic particle dynamics and their effect on Callisto's environment. From this, we provide a map of global energetic particle precipitation onto Callisto's surface, which may contribute to the generation of its atmosphere.
Plasma–Surface Interactions Under High Heat and Particle Fluxes
Directory of Open Access Journals (Sweden)
Gregory De Temmerman
2013-01-01
Full Text Available The plasma-surface interactions expected in the divertor of a future fusion reactor are characterized by extreme heat and particle fluxes interacting with the plasma-facing surfaces. Powerful linear plasma generators are used to reproduce the expected plasma conditions and allow plasma-surface interactions studies under those very harsh conditions. While the ion energies on the divertor surfaces of a fusion device are comparable to those used in various plasma-assited deposition and etching techniques, the ion (and energy fluxes are up to four orders of magnitude higher. This large upscale in particle flux maintains the surface under highly non-equilibrium conditions and bring new effects to light, some of which will be described in this paper.
Particle-solid interactions and 21st century materials science
International Nuclear Information System (INIS)
Feldman, L.C.; Lupke, G.; Tolk, N.H.; Lopez, R.; Haglund, R.F.; Haynes, T.E.; Boatner, L.A.
2003-01-01
The basic physics that governs the interaction of energetic ion beams with solids has its roots in the atomic and nuclear physics of the last century. The central formalism of Jens Lindhard, describing the 'particle-solid interaction', provides a valuable quantitative guide to statistically meaningful quantities such as energy loss, ranges, range straggling, channeling effects, sputtering coefficients, and damage intensity and profiles. Modern materials modification (nanoscience, solid state dynamics) requires atomic scale control of the particle-solid interaction. Two recent experimental examples are discussed: (1) the control of the size distribution of nanocrystals formed in implanted materials and (2) the investigation of the site-specific implantation of hydrogen into silicon. Both cases illustrate unique solid-state configurations, created by ion implantation, that address issues of current materials science interest
Introduction to supersymmetry and its applications to particle interactions
International Nuclear Information System (INIS)
Fayet, P.
1978-01-01
The fundamental mechanisms are first studied: spontaneous breaking of gauge invariance and supersymmetry, definition of conserved quantum numbers. Then it is shown how to construct spontaneously broken supersymmetric gauge theories of weak and electromagnetic interactions. Supersymmetry associates a neutrino to the photon; new leptons and Higgs scalars to heavy vector bosons; heavy scalar particles to usual leptons and quarks. The Goldstone neutrino and photon neutrino belong to a new class of leptons, with its own quantum number, R; R-conservation explains why these neutrinos have not yet been observed. Particles with R=0 are those of usual gauge theories, gauge bosons, fermions and Higgs scalars; the others lead to new weak interactions phenomena, where scalars can be exchanged. Finally, it is shown how strong and gravitational interactions can also be included [fr
Waves, particles, and storms in geospace a complex interplay
Daglis, Ioannis A; Mann, Ian R
2017-01-01
Geospace features highly dynamic populations of charged particles with a wide range of energies from thermal to ultra-relativistic. Influenced by magnetic and electric fields in the terrestrial magnetosphere driven by solar wind forcing, changes in the numbers and energies of these particles lead to a variety of space weather phenomena, some of which are detrimental to space infrastructure. This book includes investigations relevant to understanding and forecasting this space environment and the adverse impacts of space weather. High-energy electrons and ions in the Van Allen radiation belts and the ring current are of particular interest and importance with regard to the operation of space-based technological infrastructure upon which 21st century civilization increasingly relies. This book presents an overview of the latest discoveries, current scientific understanding, and the latest research on the sources, transport, acceleration and loss of these energetic particle populations, as well as their coupling...
Scenarios for the nonlinear evolution of alpha particle induced Alfven wave instability
International Nuclear Information System (INIS)
Berk, H.L.; Breizman, B.N.; Ye, Huanchun.
1992-03-01
Various nonlinear scenarios are given for the evolution of energetic particles that are slowing down in a background plasma and simultaneously causing instability of the background plasma waves. If the background damping is sufficiently weak, a steady-state wave is established as described by Berk and Breizman. For larger background damping rate pulsations develop. Saturation occurs when the wave amplitude rises to where the wave trapping frequency equals the growth rate. The wave then damps due to the small background dissipation present and a relatively long quiet interval exists between bursts while the free energy of the distribution is refilled by classical transport. In this scenario the anomalous energy loss of energetic particles due to diffusion is small compared to the classical collisional energy exchange with the background plasma. However, if at the trapping frequency, the wave amplitude is large enough to cause orbit stochasticity, a phase space ''explosion'' occurs where the wave amplitudes rise to higher levels which leads to rapid loss of energetic particles
Two-particle versus three-particle interactions in single ionization of helium by ion impact
International Nuclear Information System (INIS)
Schulz, M; Moshammer, R; Fischer, D; Ullrich, J
2004-01-01
We have performed kinematically complete experiments on single ionization of He by 100 MeV amu -1 C 6+ and 3.6 MeV amu -1 Au 24,53+ impact. By analysing doubly differential cross sections (DDCS) as a function of the momenta of all two-particle sub-systems we studied the importance of two-particle interactions. Furthermore, presenting the squared momenta of all three collision fragments simultaneously in a Dalitz plot, we evaluated the role of three-particle interactions. Finally, both for the DDCS and the Dalitz plots the corresponding correlation function was analysed. While the absolute cross sections confirm that ionization predominantly leads to a momentum exchange between the electron and the recoil-ion, the correlation function reveals strong correlations between the particles of any two-particle sub-system. Three-particle correlations, which are not accounted for by perturbative calculations, are quite significant as well, at least for certain kinematic conditions
Horizon wave function for single localized particles: GUP and quantum black-hole decay
International Nuclear Information System (INIS)
Casadio, Roberto; Scardigli, Fabio
2014-01-01
A localized particle in Quantum Mechanics is described by a wave packet in position space, regardless of its energy. However, from the point of view of General Relativity, if the particle's energy density exceeds a certain threshold, it should be a black hole. To combine these two pictures, we introduce a horizon wave function determined by the particle wave function in position space, which eventually yields the probability that the particle is a black hole. The existence of a minimum mass for black holes naturally follows, albeit not in the form of a sharp value around the Planck scale, but rather like a vanishing probability that a particle much lighter than the Planck mass may be a black hole. We also show that our construction entails an effective generalized uncertainty principle (GUP), simply obtained by adding the uncertainties coming from the two wave functions associated with a particle. Finally, the decay of microscopic (quantum) black holes is also described in agreement with what the GUP predicts. (orig.)
Assessment of seismic wave effects on soil-structure interaction
International Nuclear Information System (INIS)
Bernreuter, D.L.
1977-01-01
One of the most common hypotheses made for soil-structure interaction analyses is that the earthquake input motion is identical at all points beneath the structure. Several papers have recently shown that this assumption may be overly conservative and that the effect of wave passage is extremely important. These studies typically employ a relatively simple model, namely, the basemat is represented by a rectangular rigid foundation resting on top of the soil and connected to the soil by a continuously distributed set of soil springs. The seismic input is applied at the base of the soil springs and is assumed to be traveling at a constant wave velocity across the site. It ispossible to improve on the soil/structure model by use of finite element methods; however, little is known about how to model the input seismic energy and typically a simple travelling wave is used. In this paper, the author examines the available data to determine: (i) the appropriate wave velocity to use, and (ii) if the currently availble analytic models are adequate. (Auth.)
Electromagnetic interactions in relativistic infinite component wave equations
International Nuclear Information System (INIS)
Gerry, C.C.
1979-01-01
The electromagnetic interactions of a composite system described by relativistic infinite-component wave equations are considered. The noncompact group SO(4,2) is taken as the dynamical group of the systems, and its unitary irreducible representations, which are infinite dimensional, are used to find the energy spectra and to specify the states of the systems. First the interaction mechanism is examined in the nonrelativistic SO(4,2) formulation of the hydrogen atom as a heuristic guide. A way of making a minimal relativistic generalization of the minimal ineractions in the nonrelativistic equation for the hydrogen atom is proposed. In order to calculate the effects of the relativistic minimal interactions, a covariant perturbation theory suitable for infinite-component wave equations, which is an algebraic and relativistic version of the Rayleigh-Schroedinger perturbation theory, is developed. The electric and magnetic polarizabilities for the ground state of the hydrogen atom are calculated. The results have the correct nonrelativistic limits. Next, the relativistic cross section of photon absorption by the atom is evaluated. A relativistic expression for the cross section of light scattering corresponding to the seagull diagram is derived. The Born amplitude is combusted and the role of spacelike solutions is discussed. Finally, internal electromagnetic interactions that give rise to the fine structure splittings, the Lamb shifts and the hyperfine splittings are considered. The spin effects are introduced by extending the dynamical group
Interaction of High Intensity Electromagnetic Waves with Plasmas: Final Report
International Nuclear Information System (INIS)
Shvets, G.
2008-01-01
The focus of our work during the duration of this grant was on the following areas: (a) the fundamental plasma physics of intense laser-plasma interactions, including the nonlinear excitation of plasma waves for accelerator applications, as well as the recently discovered by us phenomenon of the relativistic bi-stability of relativistic plasma waves driven by a laser beatwave; (b) interaction of high power microwave beams with magnetized plasma, including some of the recently discovered by us phenomena such as the Undulator Induced Transparency (UIT) as well as the new approaches to dynamic manipulation of microwave pulses; (c) investigations of the multi-color laser pulse interactions in the plasma, including the recently discovered by us phenomenon of Electromagnetic Cascading (EC) and the effect of the EC of three-dimensional dynamics of laser pulses (enhanced/suppressed selffocusing etc.); (d) interaction of high-current electron beams with the ambient plasma in the context of Fast Ignitor (FI) physics, with the emphasis on the nonlinear dynamics of the Weibel instability and beam filamentation.
Interaction of Macro-particles with LHC proton beam
Zimmermann, F; Xagkoni, A
2010-01-01
We study the interaction of macro-particles residing inside the LHC vacuum chamber, e.g. soot or thermalinsulation fragments, with the circulating LHC proton beam. The coupled equations governing the motion and charging rate of metallic or dielectric micron-size macroparticles are solved numerically to determine the time spent by such “dust” particles close to the path of the beam as well as the resulting proton-beam losses, which could lead to a quench of superconducting magnets and, thereby, to a premature beam abort.
Observation of a visible charmed particle decay in neutrino interactions
International Nuclear Information System (INIS)
Cnops, A.M.; Connolly, P.L.; Kahn, S.A.
1979-01-01
In a sample of 250 semileptonic charmed particle decays (ν/sub μ/ + Neon → μ - + e + + ... events), one clear event is found where the e + does not come directly from the ν interaction vertex but from a decay point 1.1 cm downstream of the vertex. This event is interpreted as a visible charmed particle decay: into an e + and a positive and a negative charged track. The observation of a visible charm decay in the sample is consistent with what is expected if the charm lifetime were of the order 5 x 10 -13 sec. 5 references
Experimental Insights into the Mechanisms of Particle Acceleration by Shock Waves
Scolamacchia, T.; Scheu, B.; Dingwell, D. B.
2011-12-01
The generation of shock waves is common during explosive volcanic eruptions. Particles acceleration following shock wave propagation has been experimentally observed suggesting the potential hazard related to this phenomenon. Experiments and numerical models focused on the dynamics of formation and propagation of different types of shock waves when overpressurized eruptive mixtures are suddenly released in the atmosphere, using a pseudo-gas approximation to model those mixtures. Nevertheless, the results of several studies indicated that the mechanism of coupling between a gas and solid particles is valid for a limited grain-size range, which at present is not well defined. We are investigating particle acceleration mechanisms using a vertical shock tube consisting of a high-pressure steel autoclave (450 mm long, 28 mm in diameter), pressurized with argon, and a low-pressure 140 mm long acrylic glass autoclave, with the same internal diameter of the HP reservoir. Shock waves are generated by Ar decompression at atmospheric pressures at Pres/Pamb 100:1 to 150:1, through the failure of a diaphragm. Experiments were performed either with empty autoclave or suspending solid analogue particles 150 μm in size inside the LP autoclave. Incident Mach number varied from 1.7 to 2.1. Absolute and relative pressure sensors monitored P histories during the entire process, and a high-speed camera recorded particles movement at 20,000 to 30,000 fps. Preliminary results indicate pressure multiplication at the contact between shock waves and the particles in a time lapse of 100s μs, suggesting a possible different mechanism with respect to gas-particle coupling for particle acceleration.
Acceleration of particles by electron plasma waves in a moderate magnetic field
International Nuclear Information System (INIS)
Smith, D.F.
1976-01-01
A general scheme is established to examine any magnetohydrodynamic (MHD) configuration for its acceleration potential including the effects of various types of plasma waves. The analysis is restricted to plasma waves in a magnetic field with electron cyclotron frequency less than, but comparable to, the electron plasma frequency (moderate field). The general role of electron plasma waves is examined in this paper independent of a specific MHD configuration or generating mechanism in the weak turbulence limit. The evolution of arbitrary wave spectra in a non-relativistic plasma is examined, and it is shown that the nonlinear process of induced scattering on the polarization clouds of ions leads to the collapse of the waves to an almost one-dimensional spectrum directed along the magnetic field. The subsequent acceleration of non-relativistic and relativistic particles is considered. It is shown for non-relativistic particles that when the wave distribution has a negative slope the acceleration is retarded for lower velocities and enhanced for higher velocities compared to acceleration by an isotropic distribution of electron plasma waves in a magnetic field. This change in behaviour is expected to affect the development of wave spectra and the subsequent acceleration spectrum. (Auth.)
The Influence of Trapped Particles on the Parametric Decay Instability of Near-Acoustic Waves
Affolter, M.; Anderegg, F.; Dubin, D. H. E.; Driscoll, C. F.
2017-10-01
We present quantitative measurements of a decay instability to lower frequencies of near-acoustic waves. These experiments are conducted on pure ion plasmas confined in a cylindrical Penning-Malmberg trap. The axisymmetric, standing plasma waves have near-acoustic dispersion, discretized by the axial wave number kz =mz(π /Lp) . The nonlinear coupling rates are measured between large amplitude mz = 2 (pump) waves and small amplitude mz = 1 (daughter) waves, which have a small frequency detuning Δω = 2ω1 -ω2 . Classical 3-wave parametric coupling rates are proportional to pump wave amplitude as Γ (δn2 /n0) , with oscillatory energy exchange for Γ Δω / 2 . Experiments on cold plasmas agree quantitatively for oscillatory energy exchange, and agree within a factor-of-two for decay instability rates. However, nascent theory suggest that this latter agreement is merely fortuitous, and that the instability mechanism is trapped particles. Experiments at higher temperatures show that trapped particles reduce the instability threshold below classical 3-wave theory predictions. Supported by NSF Grant PHY-1414570, and DOE Grants DE-SC0002451 and DE-SC0008693. M. Affolter is supported by the DOE FES Postdoctoral Research Program administered by ORISE for the DOE. ORISE is managed by ORAU under DOE Contract Number DE-SC0014664.
Theoretical Studies of Strongly Interacting Fine Particle Systems
Fearon, Michael
Available from UMI in association with The British Library. A theoretical analysis of the time dependent behaviour of a system of fine magnetic particles as a function of applied field and temperature was carried out. The model used was based on a theory assuming Neel relaxation with a distribution of particle sizes. This theory predicted a linear variation of S_{max} with temperature and a finite intercept, which is not reflected by experimental observations. The remanence curves of strongly interacting fine-particle systems were also investigated theoretically. It was shown that the Henkel plot of the dc demagnetisation remanence vs the isothermal remanence is a useful representation of interactions. The form of the plot was found to be a reflection of the magnetic and physical microstructure of the material, which is consistent with experimental data. The relationship between the Henkel plot and the noise of a particulate recording medium, another property dependent on the microstructure, is also considered. The Interaction Field Factor (IFF), a single parameter characterising the non-linearity of the Henkel plot, is investigated. These results are consistent with a previous experimental study. Finally the results of the noise power spectral density for erased and saturated recording media are presented, so that characterisation of interparticle interactions may be carried out with greater accuracy.
Radial diffusion of toroidally trapped particles induced by lower hybrid and fast waves
International Nuclear Information System (INIS)
Krlin, L.
1992-10-01
The interaction of RF field with toroidally trapped particles (bananas) can cause their intrinsic stochastically diffusion both in the configuration and velocity space. In RF heating and/or current drive regimes, RF field can interact with plasma particles and with thermonuclear alpha particles. The aim of this contribution is to give some analytical estimates of induced radial diffusion of alphas and of ions. (author)
Influence of the interaction of ions-dust grains on ion acoustic wave and dust acoustic wave
International Nuclear Information System (INIS)
Hua Jianjun; Liu Jinyuan; Ma Tengcai
2004-01-01
Based on a set of hydrodynamic equations and a linear time-dependent perturbation theory, the influence of the interaction of ions-dust grains on ion acoustic wave IAW and dust acoustic wave DAW in dusty plasma is analyzed. The results show that the interaction makes IAW more stable and DAW less stable
Exploiting evanescent-wave amplification for subwavelength low-contrast particle detection
Roy, S.; Pereira, S. F.; Urbach, H. P.; Wei, Xukang; El Gawhary, O.
2017-07-01
The classical problem of subwavelength particle detection on a flat surface is especially challenging when the refractive index of the particle is close to that of the substrate. We demonstrate a method to improve the detection ability several times for such a situation, by enhancing the "forbidden" evanescent waves in the substrate using the principle of super-resolution with evanescent waves amplification. The working mechanism of the system and experimental validation from a design with a thin single dielectric layer is presented. The resulting system is a simple but complete example of evanescent-wave generation, amplification, and the consequent modulation of the far field. This principle can have far reaching impact in the field of particle detection in several applications ranging from contamination control to interferometric scattering microscopy for biological samples.
Alfven waves in dusty plasmas with plasma particles described by anisotropic kappa distributions
Energy Technology Data Exchange (ETDEWEB)
Galvao, R. A.; Ziebell, L. F. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP: 91501-970, Porto Alegre, Rio Grande do Sul (Brazil); Gaelzer, R. [Instituto de Fisica e Matematica, Universidade Federal de Pelotas, Caixa Postal 354-Campus UFPel, CEP: 96010-900 Pelotas, Rio Grande do Sul (Brazil); Juli, M. C. de [Centro de Radio-Astronomia e Astrofisica Mackenzie-CRAAM, Universidade Presbiteriana Mackenzie, Rua da Consolacao 896, CEP: 01302-907 Sao Paulo, Sao Paulo (Brazil)
2012-12-15
We utilize a kinetic description to study the dispersion relation of Alfven waves propagating parallelly to the ambient magnetic field in a dusty plasma, taking into account the fluctuation of the charge of the dust particles, which is due to inelastic collisions with electrons and ions. We consider a plasma in which the velocity distribution functions of the plasma particles are modelled as anisotropic kappa distributions, study the dispersion relation for several combinations of the parameters {kappa}{sub Parallel-To} and {kappa}{sub Up-Tack }, and emphasize the effect of the anisotropy of the distributions on the mode coupling which occurs in a dusty plasma, between waves in the branch of circularly polarized waves and waves in the whistler branch.
Particle scavenging in a cylindrical ultrasonic standing wave field using levitated drops
Merrell, Tyler; Saylor, J. R.
2015-11-01
A cylindrical ultrasonic standing wave field was generated in a tube containing a flow of particles and fog. Both the particles and fog drops were concentrated in the nodes of the standing wave field where they combined and then grew large enough to fall out of the system. In this way particles were scavenged from the system, cleaning the air. While this approach has been attempted using a standing wave field established between disc-shaped transducers, a cylindrical resonator has not been used for this purpose heretofore. The resonator was constructed by bolting three Langevin transducers to an aluminum tube. The benefit of the cylindrical geometry is that the acoustic energy is focused. Furthermore, the residence time of the particle in the field can be increased by increasing the length of the resonator. An additional benefit of this approach is that tubes located downstream of the resonator were acoustically excited, acting as passive resonators that enhanced the scavenging process. The performance of this system on scavenging particles is presented as a function of particle diameter and volumetric flow rate. It is noted that, when operated without particles, the setup can be used to remove drops and shows promise for liquid aerosol retention from systems where these losses can be financially disadvantageous and/or hazardous.
The effect of transitional particles driven by single wave
International Nuclear Information System (INIS)
Qiu Yunqing; Xia Mengfen
1987-05-01
The unperturbed separatrix crossing driven by a single wave in a tokamak plasma is discussed. The separatrix crossing is followed by a mixing process, and a small-scale structure occurs in the distribution function in h-ψ plane. The separatrix crossing is a convective process in h-ψ plane, and there is a definite crossing channel. The convective flux and the net flux in h-direction are calculated. The separatrix crossing is accompanied by a radial flux, which is composed of a directional flux and a diffusion flux. (author). 7 refs, 6 figs
Zheng, H.; Holzworth, R. H., II; Brundell, J. B.; Hospodarsky, G. B.; Jacobson, A. R.; Fennell, J. F.; Li, J.
2017-12-01
Lightning produces strong broadband radio waves, called "sferics", which propagate in the Earth-ionosphere waveguide and are detected thousands of kilometers away from their source. Global real-time detection of lightning strokes including their time, location and energy, is conducted with the World Wide Lightning Location Network (WWLLN). In the ionosphere, these sferics couple into very low frequency (VLF) whistler waves which propagate obliquely to the Earth's magnetic field. A good match has previously been shown between WWLLN sferics and Van Allen Probes lightning whistler waves. It is well known that lightning whistler waves can modify the distribution of energetic electrons in the Van Allen belts by pitch angle scattering into the loss cone, especially at low L-Shells (referred to as LEP - Lightning-induced Electron Precipitation). It is an open question whether lightning whistler waves play an important role at high L-shells. The possible interactions between energetic electrons and lightning whistler waves at high L-shells are considered to be weak in the past. However, lightning is copious, and weak pitch angle scattering into the drift or bounce loss cone would have a significant influence on the radiation belt populations. In this work, we will analyze the continuous burst mode EMFISIS data from September 2012 to 2016, to find out lightning whistler waves above L = 3. Based on that, MAGEIS data are used to study the related possible wave-particle interactions. In this talk, both case study and statistical analysis results will be presented.
Proceedings of Summer Institute on Particle Physics: the weak interaction
International Nuclear Information System (INIS)
Mosher, A.
1981-01-01
The SLAC Summer Institute on Particle Physics held its eighth session on July 28-August 8, 1980, and the focus of the meeting was The Weak Interaction. Following the now traditional format, the first seven days of the Institute were spent with the mornings given to pedagogic lectures on the experimental and theoretical foundations of the topic. This year included a very stimulating and successful series on the physics of particle detectors. In the afternoons were seminars on the various experimental tools being designed or constructed to further probe the Weak Interaction, followed by lively discussion of the morning's lectures. Again, following the usual format, the school led into a three-day topical conference at which the most recent theoretical and experimental results were presented and discussed. Abstracts of twenty-seven items from the Institute were prepared separately for the data base
Biasing secondary particle interaction physics and production in MCNP6
International Nuclear Information System (INIS)
Fensin, M.L.; James, M.R.
2016-01-01
Highlights: • Biasing secondary production and interactions of charged particles in the tabular energy regime. • Examining lower weight window bounds for rare events when using Russian roulette. • The new biasing strategy can speedup calculations by a factor of 1 million or more. - Abstract: Though MCNP6 will transport elementary charged particles and light ions to low energies (i.e. less than 20 MeV), MCNP6 has historically relied on model physics with suggested minimum energies of ∼20 to 200 MeV. Use of library data for the low energy regime was developed for MCNP6 1.1.Beta to read and use light ion libraries. Thick target yields of neutron production for alphas on fluoride result in 1 production event per roughly million sampled alphas depending on the energy of the alpha (for other isotopes the yield can be even rarer). Calculation times to achieve statistically significant and converged thick target yields are quite laborious, needing over one hundred processor hours. The MUCEND code possess a biasing technique for improving the sampling of secondary particle production by forcing a nuclear interaction to occur per each alpha transported. We present here a different biasing strategy for secondary particle production from charged particles. During each substep, as the charged particle slows down, we bias both a nuclear collision event to occur at each substep and the production of secondary particles at the collision event, while still continuing to progress the charged particle until reaching a region of zero importance or an energy/time cutoff. This biasing strategy is capable of speeding up calculations by a factor of a million or more as compared to the unbiased calculation. Further presented here are both proof that the biasing strategy is capable of producing the same results as the unbiased calculation and the limitations to consider in order to achieve accurate results of secondary particle production. Though this strategy was developed for MCNP
Nonlinear interaction of colliding beams in particle storage rings
International Nuclear Information System (INIS)
Herrera, J.C.; Month, M.
1979-01-01
When two beams of high energy particles moving in opposite directions are brought into collision, a large amount of energy is available for the production of new particles. However to obtain a sufficiently high event rate for rare processes, such as the production of the intermediate vector boson (Z 0 and W +- ), large beam currents are also required. Under this circumstance, the high charge density of one beam results in a classical electromagnetic interaction on the particles in the other beam. This very nonlinear space charge force, caled the beam-beam force, limits the total circulating charge and, thereby, the ultimate performance of the colliding ring system. The basic nature of the beam-beam force is discussed, indicating how it is quite different in the case of continuous beams, which cross each other at an angle as compared to the case of bunched beams which collide head-on. Some experimental observations on the beam-beam interaction in proton-proton and electron-positron beams are then reviewed and interpreted. An important aspect of the beam-beam problem in storage rings is to determine at what point in the analysis of the particle dynamics is it relevant to bring in the concepts of stochasticity, slow diffusion, and resonance overlap. These ideas are briefly discussed
Feebly Interacting Dark Matter Particle as the Inflaton
Tenkanen, Tommi
2016-01-01
We present a scenario where a $Z_2$-symmetric scalar field $\\phi$ first drives cosmic inflation, then reheats the Universe but remains out-of-equilibrium itself, and finally comprises the observed dark matter abundance, produced by particle decays \\`{a} la freeze-in mechanism. We work model-independently without specifying the interactions of the scalar field besides its self-interaction coupling, $\\lambda\\phi^4$, non-minimal coupling to gravity, $\\xi\\phi^2R$, and coupling to another scalar f...
Double Simplex - Visualizing particles and their interactions seminar
CERN. Geneva HR-RFA
2006-01-01
The double simplex is a new way to envision the particles and interactions through a three-dimensional construction intended to serve as an invitation to narrative and a spur to curiosity. My goal is to represent what we know is true, what we hope might be true, and what we don't know. Constructing the double simplex expresses the spirit of play, of successive approximations, that animates the way scientists work.
Invasion-wave-induced first-order phase transition in systems of active particles.
Ihle, Thomas
2013-10-01
An instability near the transition to collective motion of self-propelled particles is studied numerically by Enskog-like kinetic theory. While hydrodynamics breaks down, the kinetic approach leads to steep solitonlike waves. These supersonic waves show hysteresis and lead to an abrupt jump of the global order parameter if the noise level is changed. Thus they provide a mean-field mechanism to change the second-order character of the phase transition to first order. The shape of the wave is shown to follow a scaling law and to quantitatively agree with agent-based simulations.
Wave chaos in quantum systems with point interaction
International Nuclear Information System (INIS)
Albeverio, S.; Seba, P.
1991-01-01
The authors study perturbations H of the quantized version H 0 of integrable Hamiltonian systems by point interactions. They relate the eigenvalues of H to the zeros of a certain meromorphic function ξ. Assuming the eigenvalues of H 0 are Poisson distributed, they get detailed information on the joint distribution of the zeros of ξ and give bounds on the probability density for the spacings of eigenvalues of H. Their results confirm the wave chaos phenomenon, as different from the quantum chaos phenomenon predicted by random matrix theory