Suppression of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>ω</mml:mi></mml:mrow><mml:mrow><mml:mi>ci</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>Instability in a Mirror-Confined Plasma by Injection of an Electron Beam

Klinkowstein, R. E.; Smullin, Louis D.

doi:10.1103/physrevlett.40.771

Cited by 23 publications

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“…Though later evidence would somewhat modify the details of the explanation, the general picture of the role of warm ions in suppressing microinstability in the 2XIIB experiment has continued to be borne out. This result, and those that preceded or followed it in experiments such as PR-6 or Constance I (MIT) [76], represent one of the cornerstones of the physics of mirror plasma confinement.…”

Section: Fig 10 Experimentally Measured M Versus Average Ion Energy I...mentioning

confidence: 71%

The magnetic mirror approach to fusion

1987

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The magnetic mirror approach to fusion is reviewed in depth. Starting with a brief chronological history of the development of the basic mirror concept, its subsequent evolution into the tandem mirror, the field reversed mirror and other variants is described. Also discussed are the many-faceted aspects of mirror theory, including adiabatic invariants, MHD equilibrium and stability, collisional processes, transport theory and microinstability theory. The review concludes with an updating of experimental results, a discussion of mirror-related technology, including neutral beam injection and direct conversion, and a brief description of design studies of mirror fusion power plants.

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Section: Fig 10 Experimentally Measured M Versus Average Ion Energy I...mentioning

confidence: 71%

The magnetic mirror approach to fusion

1987

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“…The original goal of the Constance 2 experiments was to investigate the "mechanism of hot electron statbilization, reported in the experiments of loffe, el al., 1975, Klinkowstein and Smullin, 1978 The hope was that by repeating the conditions under which -beam and ECRH stabilization was observed, the superior diagnostics of Constance 2 would be able to measure the electron population present during stabilization. One of the key issues to be determined by the experiments was whether or not a wtrapped electron population depressed the potential, confining cool ions and stabilizing loss-cone instabilities or whether "some other mechanism" (such as hot-electron driven turbulence) was responsible for the observed stabilization.…”

Section: Comments On Hot Electron Stablization Of Dclcmentioning

confidence: 99%

Electron-cyclotron heating in the Constance 2 mirror experiment

Mauel¹

1982

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Electron cyclotron heating of a highly-ionized plasma in mirror geomctry is investigated. Of primary interest is the experimental diagnosis of the elcctron energy distribution and the comparison of the results of this diagnosis with a two dimensional, time-dependent Fokkcr-Planck simulation. 'Tliese two goals are accomplished in four steps. (1) First, the power balance of the heated and unheated Constance 2 plasma is analyzed experimentally. It is concluded that the heated electrons escape the mirror at a rate dominated by a combination of the influx of "cool" electrons from outsidc the mirror and the increased loss rate of the ions. This analysis is used later to help construct the simulation. (2) 'l.he microwave parameters at the resonance zones are then calculated by cold-plasma ray tracing. High N 11 waves are launched. and. for these waves, strong first-pass absorption is predicted. The absorption strength is qualitatively checked in the experiment by surrounding the plasma with non-reflecting liners. (3) A simplified quasilinear theory including the effect of N 11 is developed to model the electrons. An analytic expression is derived for the RF-induced "pump-out" of the magnetically-confined "warm" electrons (Te > 100eO). Results of the Fokker-Planck simulations show the development of the electron energy distribution for several plasma conditions and verify the scaling of the analytic expression for RF-induced diffusion into the loss cone. (4) Sample x-ray and endloss data are presented, and the overall comparison between the simulation and experiment is discussed. 'rhe x-ray signals indicate that. for greater RF power, the hot electron density increases more rapidly than'its temperature. lic time history of the endloss data, illustrating RF-enhancement. suggests the predicted scaling for warm-electron "pump-out". Finally, a comparison between the measured and predicted energy distribution shows that, over die range of parameters investigated (2 X 10"cm 3 < ne < 1 x 10O'cmand (nT,) < 200ev-crn-) and within the accuracy with which the plasma parameters can be determined, the "bulk", "warm", and "hot" components of the heated Constance 2 electrons are indeed reproduced by the simulation.

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“…It is imperative to control this instability for the mirror confinement schemes to be successful. In a recent experiment, Klinkowstein and Smullin [3] have reported an interesting technique to suppress the instability, which consists in injecting an electron beam into the machine along the magnetic field lines. It has been found that it led to the suppression of the instability when the beam power in their experiment was greater than about 42 kW.…”

Section: Introductionmentioning

confidence: 99%

Effect of electron beam injection on DCLC instabilities in mirror machines

Avinash¹,

Varma²

1984

Nucl. Fusion

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A model for the effect of an electron beam on the drift cyclotron loss cone (DCLC) instabilities in mirror machines is presented. It is shown that because of the ponderomotive force of the beamgenerated plasmons, the growth rates of the DCLC instability are modified substantially. The model explains some of the observations on the Constance mirror machine where the DCLC instability was found to be quenched by the injection of an electron beam.

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Suppression ofωciInstability in a Mirror-Confined Plasma by Injection of an Electron Beam

Cited by 23 publications

References 1 publication

The magnetic mirror approach to fusion

The magnetic mirror approach to fusion

Electron-cyclotron heating in the Constance 2 mirror experiment

Effect of electron beam injection on DCLC instabilities in mirror machines

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