1. |
- Tsypin, V. S., et al.
(författare)
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Particle flows in dusty plasmas of the tokamak edge
- 2004
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 11:8, s. 4138-4141
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Tidskriftsartikel (refereegranskat)abstract
- In this Brief Communication the plasma flows and ambipolar electric field induced due to the temperature stresses on ions are estimated. These flows are similar to the plasma residual rotations in tokamaks, but are related to dust contamination of tokamak plasmas. The induced electric field might be very important for creating transport barriers in tokamaks.
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2. |
- Severo, J. H. F., et al.
(författare)
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Magnetic islands and plasma rotation in the Tokamak Chauffage Alfven Bresilien tokamak
- 2004
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 11:2, s. 846-848
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Tidskriftsartikel (refereegranskat)abstract
- Collisional plasma rotation in the Tokamak Chauffage Alfven Bresilien (TCABR) tokamak [J. H. F. Severo, I. C. Nascimento, V. S. Tsypin, and R. M. O. Galvao, Nucl. Fusion 43, 1047 (2003)] has been experimentally studied. It was found that the measured plasma poloidal rotation velocity agrees within error limits with neoclassical theoretical predictions, and toroidal velocity with experimental results obtained in analogous tokamaks, almost everywhere along the minor radius r, except for measurements at r/asimilar or equal to0.56 and r/asimilar or equal to0.89 (the minor radius of TCABR tokamak a=18 cm). For the first point, the measured plasma rotation velocities are higher than the velocity of the background plasma, respectively similar to30% and similar to10% for the poloidal and toroidal rotation velocities. Using a set of 22 Mirnov coils displaced poloidally, magnetic field perturbations were measured in shots adjusted to reproduce the ones of the previous plasma rotation measurements, and the results confirm that in the region r/asimilar or equal to0.89 the plasma rotates together with the magnetic island (3,1).
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3. |
- Severo, J. H. F., et al.
(författare)
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Neoclassical ion transport in the edge of axially-symmetric arbitrary cross-section tokamak with plasma subsonic toroidal flows
- 2002
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Ingår i: Brazilian journal of physics. - 0103-9733 .- 1678-4448. ; 32:1, s. 13-19
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Tidskriftsartikel (refereegranskat)abstract
- General metrics of large aspect ratio tokamaks is used in the paper. General expressions for the neoclassical poloidal plasma rotation V-2(theta) and radial ion heat flux Gamma(Ti) are obtained. Their dependence 2 on the squared Mach number alpha = U-zetai(2)/c(5)(2) is analyzed (here U-zetai is the ion toroidal velocity and c(s) is the sound velocity, respectively). Some interesting peculiarities of this dependence are emphasized.
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4. |
- Severo, J. H. F., et al.
(författare)
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Plasma rotation measurement in small tokamaks using an optical spectrometer and a single photomultiplier as detector
- 2007
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 78:4
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Tidskriftsartikel (refereegranskat)abstract
- The method for plasma rotation measurement in the tokamak TCABR is reported in this article. During a discharge, an optical spectrometer is used to scan sequentially spectral lines of plasma impurities and spectral lines of a calibration lamp. Knowing the scanning velocity of the diffraction grating of the spectrometer with adequate precision, the Doppler shifts of impurity lines are determined. The photomultiplier output voltage signals are recorded with adequate sampling rate. With this method the residual poloidal and toroidal plasma rotation velocities were determined, assuming that they are the same as those of the impurity ions. The results show reasonable agreement with the neoclassical theory and with results from similar tokamaks.
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5. |
- Tsypin, V. S., et al.
(författare)
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Role of trapped and circulating particles in inducing current drive and radial electric field by Alfven waves in tokamaks
- 2002
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Ingår i: Journal of Plasma Physics. - : Cambridge University Press (CUP). - 0022-3778 .- 1469-7807. ; 67, s. 301-308
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Tidskriftsartikel (refereegranskat)abstract
- Absorption by trapped particles is supposed to seriously hinder current drive by Alfven waves. However, it is shown in this paper that the same effect is rather beneficial for the emergence of the radial electric field induced by these waves, which is important for creating and maintaining transport barriers in tokamaks.
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