Radial transport in a tandem mirror

Dimonte, Guy

doi:10.1103/physrevlett.60.1390

Cited by 13 publications

(11 citation statements)

References 10 publications

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“…In Penning traps, oscillating voltages resonant with the guiding center motions of the trapped particles are used to improve particle confinement [8]. Resonance between guiding center motions and static field asymmetries has long been thought to limit the confinement times in magnetic mirror [9] and non-neutral plasma traps [10], but no clear experimental signature has been found.…”

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confidence: 99%

Resonant Particle Heating of an Electron Plasma by Oscillating Sheaths

1998

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The first unambiguous measurements of a bounce-resonance effect in a non-neutral plasma are presented. Two striking signatures are observed when a magnetized electron column is heated by oscillating an end sheath. First, the heating rate increases by a factor of 10 4 as the oscillation frequency is increased by a factor of 10 near the thermal electron bounce frequency. Second, the heating is enhanced when the sheaths at both ends are oscillated out of phase, but is suppressed when they are in phase. The measured rates are in quantitative agreement with a resonant particle heating theory. [S0031-9007(98)06580-6]

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confidence: 99%

Resonant Particle Heating of an Electron Plasma by Oscillating Sheaths

1998

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“…It is to be noted that almost invariably negative currents were measured at the end walls in discharges of the tandem mirror TMX-U 14 and Gamma-10, 21 where asymmetric applications of electron-cyclotron and neutral beam heating powers are considered one of the candidates for nonambipolar transports observed. 22 When the nonambipolar perpendicular flux ⌫ Ќ NA is considered, it is necessary to make an experimental comparison between azimuthal asymmetries in the plasmas 23 maintained by the rf excitations with mϭϪ1 and ϩ1 modes. For that purpose measurements of two-dimensional contour plots of the endloss electron temperature parallel to the magneticfield lines are performed as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Measurements on rotating ion cyclotron range of frequencies induced particle fluxes in axisymmetric mirror plasmas

et al. 1997

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A comparison of phenomenological features of plasmas is made with a special emphasis on radio-frequency induced transport, which are maintained when a set of two closely spaced dual half-turn antennas in a central cell of the Phaedrus-B axisymmetric tandem mirror ͓J. J. Browning et al., Phys. Fluids B 1, 1692 ͑1989͔͒ is phased to excite electromagnetic fields in the ion cyclotron range of frequencies ͑ICRF͒ with mϭϪ1 ͑rotating with ions͒ and mϭϩ1 ͑rotating with electrons͒ azimuthal modes. Positive and negative electric currents are measured to flow axially to the end walls in the cases of mϭϪ1 and mϭϩ1 excitations, respectively. These parallel nonambipolar ion and electron fluxes are observed to be accompanied by azimuthal ion flows in the same directions as the antenna-excitation modes m. The phenomena are argued in terms of radial particle fluxes due to a nonambipolar transport mechanism ͓Hojo and Hatori, J. Phys. Soc. Jpn. 60, 2510 ͑1991͒; Hatakeyama et al., J. Phys. Soc. Jpn. 60, 2815 ͑1991͒, and Phys. Rev. E 52, 6664 ͑1995͔͒, which are induced when azimuthally traveling ICRF waves are absorbed in the magnetized plasma column.

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“…A study of radial transport in the tandem mirror TMX-U covers non-ambipolar radial transport induced by asymmetric application of heating NUCLEAR FUSION, Vol.31. No.9 (1991) power as well as by asymmetric magnetic geometries [16]. We report here on ambipolar radial transport induced by fluctuations.…”

Section: Introductionmentioning

confidence: 92%

Control of the radial electric field and of turbulent fluctuations in a tandem mirror plasma

et al. 1991

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The characteristics of low frequency waves in the presence of E x B rotation of a tandem mirror plasma are investigated using the Fraunhofer diffraction method. The observed dispersion relations are in good agreement with those of drift waves including a Doppler shift due to the E x B rotation velocity. The effect of the radial electric field on the drift waves is studied quantitatively by applying a bias voltage to the end plates of the tandem mirror. The fluctuation level is observed to depend on the radial electric field E r . The fluctuation has a maximum value when E r = 0 and decreases with increasing E r , regardless of its sign. The radial confinement time estimated from the particle balance equation decreases as the fluctuation level increases. The dependence of the fluctuation level agrees with that evaluated from the quasi-linear theory of drift wave turbulence.

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Radial transport in a tandem mirror

Cited by 13 publications

References 10 publications

Resonant Particle Heating of an Electron Plasma by Oscillating Sheaths

Resonant Particle Heating of an Electron Plasma by Oscillating Sheaths

Measurements on rotating ion cyclotron range of frequencies induced particle fluxes in axisymmetric mirror plasmas

Control of the radial electric field and of turbulent fluctuations in a tandem mirror plasma

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