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C F Driscoll - One of the best experts on this subject based on the ideXlab platform.
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Trapped Particle Effects in the Parametric Instability of Near-Acoustic Plasma Waves.
Physical review letters, 2018Co-Authors: M. Affolter, Francois Anderegg, Daniel H. E. Dubin, Francesco Valentini, C F DriscollAbstract:Quantitative experiments on the parametric decay instability of near-acoustic plasma waves provide strong evidence that Trapped Particles reduce the instability threshold below fluid models. At low temperatures, the broad characteristics of the parametric instability are determined by the frequency detuning of the pump and daughter wave, and the wave-wave coupling strength, surprisingly consistent with cold fluid, three-wave theories. However, at higher temperatures, Trapped Particle effects dominate, and the pump wave becomes unstable at half the threshold pump wave amplitude with similar exponential growth rates as for a cold plasma.
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Trapped Particle mediated collisional damping of nonaxisymmetric plasma waves
Physical Review Letters, 2006Co-Authors: A A Kabantsev, C F DriscollAbstract:Weak axial variations in magnetic or electric confinement fields in pure electron plasmas cause slow electrons to be Trapped locally, and collisional diffusion across the trapping separatrix then causes surprisingly large Trapped-Particle-mediated (TPM) damping and transport effects. Here we characterize TPM damping of m{sub {theta}}{ne}0, m{sub z}={+-}1 Trivelpiece-Gould plasma modes in large-amplitude long-lived Bernstein-Greene-Kruskal states. The TPM damping gives {gamma}{sub BGK}/{omega}{approx}10{sup -4} and seems to dominate in regimes of weak interParticle collisions.
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Trapped-Particle-mediated collisional damping of nonaxisymmetric plasma waves.
Physical review letters, 2006Co-Authors: A A Kabantsev, C F DriscollAbstract:Weak axial variations in magnetic or electric confinement fields in pure electron plasmas cause slow electrons to be Trapped locally, and collisional diffusion across the trapping separatrix then causes surprisingly large Trapped-Particle-mediated (TPM) damping and transport effects. Here we characterize TPM damping of m theta not equal to 0, m(z) = +/-1 Trivelpiece-Gould plasma modes in large-amplitude long-lived Bernstein-Greene-Kruskal states. The TPM damping gives gammaBGK/omega approximately 10(-4) and seems to dominate in regimes of weak interParticle collisions.
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damping of the Trapped Particle diocotron mode
Physical Review Letters, 2003Co-Authors: T. J. Hilsabeck, A A Kabantsev, C F Driscoll, T M OneilAbstract:The damping mechanism of a recently discovered Trapped-Particle mode is identified as collisional velocity scattering of marginally Trapped Particles. The mode exists on non-neutral plasma columns that are partially divided by an electrostatic potential. This damping mechanism is similar to that responsible for damping of the dissipative Trapped-ion mode. The damping rate is calculated using a Fokker-Planck analysis and agrees with measurement to within 50%. Also, an experimental signature confirms a causal relation between scattering of marginally Trapped Particles and damping. Electric and magnetic field inhomogeneities in plasma containment devices cause a fraction of the Particles to remain localized in certain regions. This condition gives rise to a class of low frequency electrostatic oscillations known as Trapped-Particle modes [1]. In these modes, Trapped Particles remain isolated from the global mode
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Damping of the Trapped-Particle diocotron mode.
Physical review letters, 2003Co-Authors: T. J. Hilsabeck, A A Kabantsev, C F Driscoll, Thomas M. O'neilAbstract:The damping mechanism of a recently discovered Trapped-Particle mode is identified as collisional velocity scattering of marginally Trapped Particles. The mode exists on non-neutral plasma columns that are partially divided by an electrostatic potential. This damping mechanism is similar to that responsible for damping of the dissipative Trapped-ion mode. The damping rate is calculated using a Fokker-Planck analysis and agrees with measurement to within 50%. Also, an experimental signature confirms a causal relation between scattering of marginally Trapped Particles and damping.
A A Kabantsev - One of the best experts on this subject based on the ideXlab platform.
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Trapped Particle mediated collisional damping of nonaxisymmetric plasma waves
Physical Review Letters, 2006Co-Authors: A A Kabantsev, C F DriscollAbstract:Weak axial variations in magnetic or electric confinement fields in pure electron plasmas cause slow electrons to be Trapped locally, and collisional diffusion across the trapping separatrix then causes surprisingly large Trapped-Particle-mediated (TPM) damping and transport effects. Here we characterize TPM damping of m{sub {theta}}{ne}0, m{sub z}={+-}1 Trivelpiece-Gould plasma modes in large-amplitude long-lived Bernstein-Greene-Kruskal states. The TPM damping gives {gamma}{sub BGK}/{omega}{approx}10{sup -4} and seems to dominate in regimes of weak interParticle collisions.
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Trapped-Particle-mediated collisional damping of nonaxisymmetric plasma waves.
Physical review letters, 2006Co-Authors: A A Kabantsev, C F DriscollAbstract:Weak axial variations in magnetic or electric confinement fields in pure electron plasmas cause slow electrons to be Trapped locally, and collisional diffusion across the trapping separatrix then causes surprisingly large Trapped-Particle-mediated (TPM) damping and transport effects. Here we characterize TPM damping of m theta not equal to 0, m(z) = +/-1 Trivelpiece-Gould plasma modes in large-amplitude long-lived Bernstein-Greene-Kruskal states. The TPM damping gives gammaBGK/omega approximately 10(-4) and seems to dominate in regimes of weak interParticle collisions.
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damping of the Trapped Particle diocotron mode
Physical Review Letters, 2003Co-Authors: T. J. Hilsabeck, A A Kabantsev, C F Driscoll, T M OneilAbstract:The damping mechanism of a recently discovered Trapped-Particle mode is identified as collisional velocity scattering of marginally Trapped Particles. The mode exists on non-neutral plasma columns that are partially divided by an electrostatic potential. This damping mechanism is similar to that responsible for damping of the dissipative Trapped-ion mode. The damping rate is calculated using a Fokker-Planck analysis and agrees with measurement to within 50%. Also, an experimental signature confirms a causal relation between scattering of marginally Trapped Particles and damping. Electric and magnetic field inhomogeneities in plasma containment devices cause a fraction of the Particles to remain localized in certain regions. This condition gives rise to a class of low frequency electrostatic oscillations known as Trapped-Particle modes [1]. In these modes, Trapped Particles remain isolated from the global mode
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Damping of the Trapped-Particle diocotron mode.
Physical review letters, 2003Co-Authors: T. J. Hilsabeck, A A Kabantsev, C F Driscoll, Thomas M. O'neilAbstract:The damping mechanism of a recently discovered Trapped-Particle mode is identified as collisional velocity scattering of marginally Trapped Particles. The mode exists on non-neutral plasma columns that are partially divided by an electrostatic potential. This damping mechanism is similar to that responsible for damping of the dissipative Trapped-ion mode. The damping rate is calculated using a Fokker-Planck analysis and agrees with measurement to within 50%. Also, an experimental signature confirms a causal relation between scattering of marginally Trapped Particles and damping.
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Diagnosing the velocity-space separatrix of Trapped Particle modes
Review of Scientific Instruments, 2003Co-Authors: A A Kabantsev, C F DriscollAbstract:Trapped Particle modes in pure electron plasmas are similar to modes in neutral plasmas and exhibit damping due to velocity diffusion across the separatrix between Trapped and unTrapped Particles, as commonly occurs in neutral plasmas. Applied rf voltages cause resonant perturbation of Particle velocities near the separatrix, giving a greatly enhanced mode damping. This diagnostic technique can determine the velocity-space separatrices for either electrostatic or magnetic trapping, or determine the Particle distribution function along the separatrix.
Thomas M. O'neil - One of the best experts on this subject based on the ideXlab platform.
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Particle fluxes through the separatrix in the Trapped Particle diocotron mode
Physics of Plasmas, 2011Co-Authors: Yu. A. Tsidulko, T. J. Hilsabeck, Thomas M. O'neilAbstract:In the Trapped Particle diocotron mode, the Trapped Particles undergo E × B drift motion in a uniform B field. Since such a flow is incompressible one is tempted to assume that the Trapped Particle density is constant along a fluid element. However, this is not the case since there is interchange of Trapped and passing Particles through the separatrix. This paper shows that a corrected fluid analysis, taking into account the Particle flux through the separatrix, reproduces the same Trapped Particle density perturbation as obtained from the kinetic theory, thereby resolving confusion in earlier papers.
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Damping of the Trapped-Particle diocotron mode.
Physical review letters, 2003Co-Authors: T. J. Hilsabeck, A A Kabantsev, C F Driscoll, Thomas M. O'neilAbstract:The damping mechanism of a recently discovered Trapped-Particle mode is identified as collisional velocity scattering of marginally Trapped Particles. The mode exists on non-neutral plasma columns that are partially divided by an electrostatic potential. This damping mechanism is similar to that responsible for damping of the dissipative Trapped-ion mode. The damping rate is calculated using a Fokker-Planck analysis and agrees with measurement to within 50%. Also, an experimental signature confirms a causal relation between scattering of marginally Trapped Particles and damping.
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Trapped-Particle asymmetry modes in single-species plasmas.
Physical review letters, 2001Co-Authors: A A Kabantsev, T. J. Hilsabeck, C F Driscoll, Thomas M. O'neilAbstract:Novel Trapped-Particle asymmetry modes propagate on cylindrical electron columns when axial variations in the wall voltage cause Particle trapping. These modes consist of E x B drifts of edge-Trapped Particles, partially shielded by axial flows of interior unTrapped Particles. A simple model agrees well with the observed frequencies and eigenfunctions, but the strong mode damping is as yet unexplained. These modes may be important in coupling trap asymmetries to Particle motions and low frequency E x B drift modes.
T. J. Hilsabeck - One of the best experts on this subject based on the ideXlab platform.
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Particle fluxes through the separatrix in the Trapped Particle diocotron mode
Physics of Plasmas, 2011Co-Authors: Yu. A. Tsidulko, T. J. Hilsabeck, Thomas M. O'neilAbstract:In the Trapped Particle diocotron mode, the Trapped Particles undergo E × B drift motion in a uniform B field. Since such a flow is incompressible one is tempted to assume that the Trapped Particle density is constant along a fluid element. However, this is not the case since there is interchange of Trapped and passing Particles through the separatrix. This paper shows that a corrected fluid analysis, taking into account the Particle flux through the separatrix, reproduces the same Trapped Particle density perturbation as obtained from the kinetic theory, thereby resolving confusion in earlier papers.
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damping of the Trapped Particle diocotron mode
Physical Review Letters, 2003Co-Authors: T. J. Hilsabeck, A A Kabantsev, C F Driscoll, T M OneilAbstract:The damping mechanism of a recently discovered Trapped-Particle mode is identified as collisional velocity scattering of marginally Trapped Particles. The mode exists on non-neutral plasma columns that are partially divided by an electrostatic potential. This damping mechanism is similar to that responsible for damping of the dissipative Trapped-ion mode. The damping rate is calculated using a Fokker-Planck analysis and agrees with measurement to within 50%. Also, an experimental signature confirms a causal relation between scattering of marginally Trapped Particles and damping. Electric and magnetic field inhomogeneities in plasma containment devices cause a fraction of the Particles to remain localized in certain regions. This condition gives rise to a class of low frequency electrostatic oscillations known as Trapped-Particle modes [1]. In these modes, Trapped Particles remain isolated from the global mode
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Damping of the Trapped-Particle diocotron mode.
Physical review letters, 2003Co-Authors: T. J. Hilsabeck, A A Kabantsev, C F Driscoll, Thomas M. O'neilAbstract:The damping mechanism of a recently discovered Trapped-Particle mode is identified as collisional velocity scattering of marginally Trapped Particles. The mode exists on non-neutral plasma columns that are partially divided by an electrostatic potential. This damping mechanism is similar to that responsible for damping of the dissipative Trapped-ion mode. The damping rate is calculated using a Fokker-Planck analysis and agrees with measurement to within 50%. Also, an experimental signature confirms a causal relation between scattering of marginally Trapped Particles and damping.
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Trapped-Particle diocotron modes
Physics of Plasmas, 2003Co-Authors: T. J. Hilsabeck, T. M. O’neilAbstract:Recent experiments have characterized Trapped-Particle modes on a non-neutral plasma column [A. A. Kabantsev, C. F. Driscoll, T. J. Hilsabeck, T. M. O’Neil, and J. H. Yu, Phys. Rev. Lett. 87, 225002 (2001)], and in this paper we present a theoretical model of the modes. Theoretical predictions for the mode frequency, damping rate, and eigenmode structure are compared to experimental observation. The modes are excited on a non-neutral plasma column in which classes of Trapped and passing Particles have been created by the application of a potential barrier. The column resides in a Malmberg–Penning trap, and the barrier is created by applying a voltage to an azimuthally symmetric section of the wall near the axial mid-point of the column. Low energy Particles near the edge of the column (where the barrier is strong) are Trapped in one end or the other, while high energy Particles near the center of the column transit the entire length. The modes have azimuthal variation l=1,2,…, and odd z-symmetry. The trap...
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Trapped-Particle asymmetry modes in single-species plasmas.
Physical review letters, 2001Co-Authors: A A Kabantsev, T. J. Hilsabeck, C F Driscoll, Thomas M. O'neilAbstract:Novel Trapped-Particle asymmetry modes propagate on cylindrical electron columns when axial variations in the wall voltage cause Particle trapping. These modes consist of E x B drifts of edge-Trapped Particles, partially shielded by axial flows of interior unTrapped Particles. A simple model agrees well with the observed frequencies and eigenfunctions, but the strong mode damping is as yet unexplained. These modes may be important in coupling trap asymmetries to Particle motions and low frequency E x B drift modes.
Paolo Tombesi - One of the best experts on this subject based on the ideXlab platform.
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stochastic phase space localization for a single Trapped Particle
Physical Review A, 2000Co-Authors: Stefano Mancini, David Vitali, Paolo TombesiAbstract:We propose a feedback scheme to control the vibrational motion of a single Trapped Particle based on indirect measurements of its position. It results in the possibility of a motional phase-space uncertainty contraction, corresponding to cool the Particle close to the motional ground state.
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Stochastic phase-space localization for a single Trapped Particle
Physical Review A, 2000Co-Authors: Stefano Mancini, David Vitali, Paolo TombesiAbstract:We propose a feedback scheme to control the vibrational motion of a single Trapped Particle based on indirect measurements of its position. It results the possibility of a motional phase space uncertainty contraction, correponding to cool the Particle close to the motional ground state.Comment: 9 pages, 1 figure. Concluding section and figure revised. In press on Phys. rev.
