The Experts below are selected from a list of 4302 Experts worldwide ranked by ideXlab platform
Jörg Ruppert - One of the best experts on this subject based on the ideXlab platform.
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sonic Mach Cones induced by fast partons in a perturbative quark gluon plasma
Physical Review C, 2008Co-Authors: R. B. Neufeld, Jörg Ruppert, Berndt MullerAbstract:We derive the space-time distribution of energy and momentum deposited by a fast parton traversing a weakly coupled quark-gluon plasma by treating the fast parton as the source of an external color field perturbing the medium. We then use our result as a source term for the linearized hydrodynamical equations of the medium. We show that the solution contains a sonic Mach Cone and a dissipative wake if the parton moves at a supersonic speed.
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Mach Cone shock waves at RHIC
arXiv: High Energy Physics - Phenomenology, 2007Co-Authors: Jörg Ruppert, Thorsten RenkAbstract:Energy and momentum lost by hard jets propagating through hot and dense nuclear matter have to be redistributed in the medium. It has been conjectured that collective sound modes are excited. Those lead to Mach Cone nuclear shock waves in the nuclear medium that are shown to account for three and four particle angular correlation structures of hadrons with a (semi-)hard trigger hadron in heavy-ion collisions at RHIC.
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Jet-medium interactions: Wakes in the QCD medium
Acta Physica Hungarica Series A Heavy Ion Physics, 2006Co-Authors: Jörg RuppertAbstract:We calculate the wake induced in a hot, dense QCD medium by a fast parton in the framework of linear response theory. We discuss two different scenarios: i) a weakly coupled quark gluon plasma (pQGP) described by hardthermal loop (HTL) perturbation theory and ii) a scenario where the plasma has the properties of a quantum liquid. We show that a Mach Cone can appear in the second scenario, but not in the first one.
Mathias Fink - One of the best experts on this subject based on the ideXlab platform.
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Sonic boom in soft materials: The elastic Cerenkov effect
Applied Physics Letters, 2004Co-Authors: Jeremy Bercoff, Mickaël Tanter, Mathias FinkAbstract:We report an experimental evidence of an elastic sonic boom in soft materials. Our approach is based on the ultrasonic remote generation, inside soft media, of a supersonic moving source radiating shear waves in a Mach Cone. In analogy with the Cerenkov electromagnetic radiation emitted by a beam of charged particles moving at a speed greater than the speed of light, an intense shear wave is radiated in soft materials. Such Mach waves are sensitive to medium elasticity inhomogeneities and are of great interest for ultrasound-based medical imaging applications.
R. B. Neufeld - One of the best experts on this subject based on the ideXlab platform.
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Mach Cone signal and energy deposition scenarios in linearized hydrodynamics
Physical Review C, 2010Co-Authors: R. B. Neufeld, Thorsten RenkAbstract:Particle correlation measurements associated with a hard or semihard trigger in heavy-ion collisions may reflect Mach Cone shock waves excited in the bulk medium by partonic energy loss. This is of great interest because, when compared with theory, such measurements can provide information on the transport properties of the medium. Specifically, the formation of Mach Cone shock waves is sensitive to the viscosity and speed of sound, as well as the detailed nature of the jet-medium interaction. However, modeling the physics of shock-wave excitation to obtain a meaningful comparison with measured correlations is very challenging, as the correlations arise from an interplay of perturbative as well as nonperturbative phenomena at different momentum scales. In this work we take a step in that direction by presenting a systematic study of the dependence of azimuthal particle correlations on the spatiotemporal structure of energy deposition into the medium. Our results indicate that detailed modeling of the evolution of an initially produced hard parton and the interaction of this evolving state with the medium is crucial, as both the magnitude and the shape of the shock-wave signal show a strong dependence on the assumptions being made.
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sonic Mach Cones induced by fast partons in a perturbative quark gluon plasma
Physical Review C, 2008Co-Authors: R. B. Neufeld, Jörg Ruppert, Berndt MullerAbstract:We derive the space-time distribution of energy and momentum deposited by a fast parton traversing a weakly coupled quark-gluon plasma by treating the fast parton as the source of an external color field perturbing the medium. We then use our result as a source term for the linearized hydrodynamical equations of the medium. We show that the solution contains a sonic Mach Cone and a dissipative wake if the parton moves at a supersonic speed.
C T Russell - One of the best experts on this subject based on the ideXlab platform.
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initial venus express magnetic field observations of the venus bow shock location at solar minimum
Planetary and Space Science, 2008Co-Authors: C T Russell, T L Zhang, M Delva, W Baumjohann, M Volwerk, S Barabash, M A Balikhin, S A Pope, K H GlassmeierAbstract:Abstract In this study, magnetic field measurements obtained by the Venus Express spacecraft are used to determine the bow shock position at solar minimum. The best fit of bow shock location from solar zenith angle 20–120° gives a terminator bow shock location of 2.14 R V (1 R V =6052 km) which is 1600 km closer to Venus than the 2.40 R V determined during solar maximum conditions, a clear indication of the solar cycle variation of the Venus bow shock location. The best fit to the subsolar bow shock is 1.32 R V , with the bow shock completely detached. Finally, a global bow shock model at solar minimum is constructed based on our best-fit empirical bow shock in the sunlit hemisphere and an asymptotic limit of the distant bow shock which is a Mach Cone under typical Mach number of 5.5 at solar minimum. We also describe our approach to making the measurements and processing the data in a challenging magnetic cleanliness environment. An initial evaluation of the accuracy of measurements shows that the data are of a quality comparable to magnetic field measurements made onboard magnetically clean spacecraft.
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hydrodynamic and mhd equations across the bow shock and along the surfaces of planetary obstacles
Space Science Reviews, 1997Co-Authors: S M Petrinec, C T RussellAbstract:Examinations of the magnetohydrodynamic (MHD) equations across a bow shock are presented. These equations are written in the familiar Rankine–Hugoniot set, and an exact solution to this set is given which involves the upstream magnetosonic Mach number, plasma β, polytropic index, and θB-v, as a function of position along the shock surface. The asymptotic Mach Cone angle of the shock surface is also given as a function of the upstream parameters, as a set of transcendental equations. The standoff position of a detached bow shock from an obstacle is also reviewed. In addition, a detailed examination of the hydrodynamic equations along the boundary of the obstacle is performed. Lastly, the MHD relations along the obstacle surface are examined, for specific orientations of the upstream interplanetary magnetic field (IMF) in relation to the upstream flow velocity vector.
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HYDRODYNAMIC AND MHD EQUATIONS ACROSS THE BOW SHOCK AND ALONG THE SURFACES OF PLANETARY OBSTACLES
Space Science Reviews, 1997Co-Authors: S M Petrinec, C T RussellAbstract:Examinations of the magnetohydrodynamic (MHD) equations across a bow shock are presented. These equations are written in the familiar Rankine–Hugoniot set, and an exact solution to this set is given which involves the upstream magnetosonic Mach number, plasma β, polytropic index, and θ_ B-v , as a function of position along the shock surface. The asymptotic Mach Cone angle of the shock surface is also given as a function of the upstream parameters, as a set of transcendental equations. The standoff position of a detached bow shock from an obstacle is also reviewed. In addition, a detailed examination of the hydrodynamic equations along the boundary of the obstacle is performed. Lastly, the MHD relations along the obstacle surface are examined, for specific orientations of the upstream interplanetary magnetic field (IMF) in relation to the upstream flow velocity vector.
Jeremy Bercoff - One of the best experts on this subject based on the ideXlab platform.
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Sonic boom in soft materials: The elastic Cerenkov effect
Applied Physics Letters, 2004Co-Authors: Jeremy Bercoff, Mickaël Tanter, Mathias FinkAbstract:We report an experimental evidence of an elastic sonic boom in soft materials. Our approach is based on the ultrasonic remote generation, inside soft media, of a supersonic moving source radiating shear waves in a Mach Cone. In analogy with the Cerenkov electromagnetic radiation emitted by a beam of charged particles moving at a speed greater than the speed of light, an intense shear wave is radiated in soft materials. Such Mach waves are sensitive to medium elasticity inhomogeneities and are of great interest for ultrasound-based medical imaging applications.
