Stabilization of Interchange Modes in Mirror Plasmas by a Nonlinear rf-Plasma Wave Coupling Process

Jhang, Hogun; Lee, S. G.; Kim, S. S.; Park, B. H.; Bak, J. G.

doi:10.1103/physrevlett.95.035005

Cited by 9 publications

(5 citation statements)

References 16 publications

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“…There was a probe array on each end of Hanbit with four probes so arranged that there were two probes on a field line 90 • apart in four azimuthal locations, the same system as used in previous studies on Hanbit by Jhang et al [3] and Yoon et al [19]. The same checks were made as for those experiments.…”

Section: Probe Data Analysis For the Divertor Experimentsmentioning

confidence: 99%

“…Hanbit [1] is about half of the original TARA [2] tandem mirror device from MIT. Earlier work in Hanbit [3] showed that it was possible to stabilize the m = −1 flute type MHD instability with RF power near the cyclotron resonance by the sideband coupling process. We undertook investigations to see whether the m = −1 MHD flute-like instability could be stabilized by a mirror divertor [4][5][6][7] and the kinetic stabilizer (KS) of Post et al [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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Mirror stabilization experiments in the Hanbit device

England

Lee

et al. 2009

Nucl. Fusion

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The Hanbit magnetic mirror device has been involved in a series of experiments on stabilization of the MHD flute type mode. We undertook investigations to see whether a divertor and the kinetic stabilizer (KS) of Post et al can stabilize the MHD instability. The Hanbit divertor configuration used one of the central cell coils with reversed current as the divertor coil and two other coils with increased current to compensate the field droop. The divertor eliminated the m = −1 instability when the null point was inside the vacuum tank. The KS used microwave produced plasmas on field lines in the cusp tank region. Two coils on the cusp tank were configured to produce expanding field lines with a large positive radius of curvature. A 5 kW 2.45 GHz magnetron was used to produce an electron cyclotron resonance heated plasma pressure in this region. A reduction in instability duration was observed for high power plasmas. However, for low power plasmas that terminate violently with an m = −1 instability, the KS action made the duration of the instability longer.

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Section: Probe Data Analysis For the Divertor Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mirror stabilization experiments in the Hanbit device

England

Lee

et al. 2009

Nucl. Fusion

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“…Generation or injection of strong waves into mirror machines results in a strong wave-particle interaction. In this case, the excitation of sideband waves induced by particle trapping is observed in laboratory experiments [47,48]. Potentially, the effects considered in our study can explain formation of such secondary (sideband) wave emissions.…”

Section: Discussionmentioning

confidence: 59%

Generation of discrete structures in phase-space via charged particle trapping by an electrostatic wave

Vainchtein

Fridman

Artemyev

2017

Communications in Nonlinear Science and Numerical Simulation

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The wave-particle resonant interaction plays an important role in the charged particle energization by trapping (capture) into resonance. For the systems with waves propagating through inhomogeneous plasma, the key small parameter is the ratio of the wave wavelength to a characteristic spatial scale of inhomogeneity. When that parameter is very small, the asymptotic methods are applicable for the system description, and the resultant energy distribution of trapped particle ensemble has a typical Gaussian profile around some mean value. However, for moderate values of that parameter, the energy distribution has a fine structure including several maxima, each corresponding to the discrete number of oscillations a particle makes in the trapped state. We explain this novel effect which can play important role for generation of unstable distributions of accelerated particles in many space plasma systems.

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“…Appearance of accelerated particle populations in the Free-Electron Laser experiments with Variable Parameter Wigglers [99,100] is described by essentially the same equations as trapping into the cyclotron resonance with electromagnetic waves. Generation or injection of strong waves into mirror machines result in a strong wave-particle interaction and excitation of sideband waves induced by particle trapping [e.g., 101,102]. Electron surface acceleration in the ultraintense laser pulse experiments represents a classical example of electron trapping into the Cherenkov resonance [103].…”

Section: Space and Laboratory Plasma Systems With Resonant Wave-partimentioning

confidence: 99%

Trapping (capture) into resonance and scattering on resonance: Summary of results for space plasma systems

Artemyev

Neishtadt

Vainchtein

et al. 2018

Communications in Nonlinear Science and Numerical Simulation

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In the present review we survey space plasma systems where the nonlinear resonant interaction between charged particles and electromagnetic waves plays an important role. We focus on particle acceleration by strong electromagnetic waves. We start with presenting a general description of nonlinear resonant interaction based on the theory of slowfast Hamiltonian systems with resonances. Then we turn to several manifestations of the resonance effects in various space plasma systems. We describe a universal approach for evaluating main characteristics of the resonant particle dynamics: probability of trapping into resonance, energy change due to scattering and trapping. Then we demonstrate how effects of nonlinear resonant trapping and scattering can be combined in a generalized kinetic equation. We also discuss the stability of trapped motion and evolution of particle ensemble in systems with trapping. The main objective of this review is to provide a general approach for characterizing plasma systems with nonlinear resonant interactions.

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Stabilization of Interchange Modes in Mirror Plasmas by a Nonlinear rf-Plasma Wave Coupling Process

Cited by 9 publications

References 16 publications

Mirror stabilization experiments in the Hanbit device

Mirror stabilization experiments in the Hanbit device

Generation of discrete structures in phase-space via charged particle trapping by an electrostatic wave

Trapping (capture) into resonance and scattering on resonance: Summary of results for space plasma systems

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