| 1. |
- Arber, T. D., et al.
(författare)
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Large Larmor Radius Stability of the Z-pinch
- 1994
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 72, s. 2399-
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Tidskriftsartikel (refereegranskat)abstract
- The linear m=0 stability of the z pinch in the collisionless, large ion Larmor radius regime is examined using the Vlasov fluid model. The results reveal a strong equilibrium dependence. The uniform current density equilibrium shows a reduction in growth rate when the average ion Larmor radius is about one-fifth of the pinch radius. However, finite Larmor radius effects cannot in themselves produce a stabilized z pinch.
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| 2. |
- Brunsell, P., et al.
(författare)
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Extrap L-1 Experimental Stability
- 1990
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Ingår i: XVII European Conference on Controlled Fusion and Plasma Heating, Amsterdam, Netherlands, June 25-29, 1990. ; , s. 610-
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Konferensbidrag (refereegranskat)
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| 3. |
- Coppins, M., et al.
(författare)
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Anisotropic Z-Pinch Equilibria and Their Stability
- 1992
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Ingår i: Physics of fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; B4, s. 3251-
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Tidskriftsartikel (refereegranskat)abstract
- The Chew–Goldberger–Low equations are used to study the effect of pressure anisotropy on Z‐pinches operating in the collisionless regime. The limitations on the form of accessible equilibria are investigated. The effect on the m=0 instability is asessed both by means of the energy principle and by direct solution of the eigenvalue equation for a variety of anisotropicequilibria. The results indicate that in the small Larmor radius limit pressure anisotropy offers a rather slight enhancement of the linear stability of the Z‐pinch.
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| 4. |
- Coppins, M., et al.
(författare)
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FIGARO-a Large Larmor Radius Stability Code
- 1992
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Ingår i: International Conference on Plasma Physics, Innsbruck, Austria, 29 June - 3 July, 1992. ; , s. 663-
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Konferensbidrag (refereegranskat)
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Lehnert, B., et al.
(författare)
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Parameter Limits of Screw-Pinch Equilibria
- 1992
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Ingår i: Plasma Physics and Controlled Fusion. - 0741-3335 .- 1361-6587. ; 34, s. 1113-1131
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Tidskriftsartikel (refereegranskat)abstract
- Anisotropic resistivity causes paramagnetic effects (Bz´(r) < 0) in a screw pinch, being basically different to the self-relaxation in reversed field-pinches. We compute, analytically and numerically, the resulting influence on the plasma radius and on plasma beta in a straight cylindrical plasma. The results seem to indicate that D-D screw-pinch reactors which depend on safety factors q(a) > 1 are unattainable. Diamagnetism caused by radial particle diffusion and the Nernst effect is also discussed. In a Tokamak or reactor plasma, diamagnetism is shown to be negligible, whereas it may contribute in present ultra-low q, Extrap and RFP experiments.A basic relation is derived for the coupling betwecn the poloidal and axial magnetic field components with the above effects included. Of specific importance to the Extrap programme is the result that plasma current limitation can arise due to the lack equilibrium when the plasma radius tends to exceed its upper limit, which is defined by a magnetic or material limiter. Comparisons are made with stability limits depending on the safety factor, the number of contained ion Larmor radii and the line density.
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| 9. |
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| 10. |
- Li., J., et al.
(författare)
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Boundary Larmor Radius Effect on Electrostatic Waves
- 1991
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Ingår i: Physics of fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; B3, s. 3013-
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Tidskriftsartikel (refereegranskat)abstract
- The linearized Vlasov–Poisson equations, which combine to an integrodifferential equation for the perturbed electric potential, are used to investigate the effect of finite plasma size on the stability of electrostatic waves in a homogeneous plasma slab. The distortion of the gyromotion of the particles at the plasma boundary influences wave stability, a phenomenon termed the boundary Larmor radius (BLR) effect. The integrodifferential equation, treated as an eigenvalue problem, is discretized into a matrix dispersion equation by use of the Galerkin method and is then solved numerically. It is found that the ion Bernstein wave,which is undamped in an infinite homogeneous plasma, now becomes damped with a maximum damping rate of 0.35 ωci at rG/L (ion Larmor radius over wall distance)≊0.15. In general, the damping is less pronounced at shorter perpendicular wavelengths. It implies a necessity to take into account the BLR effect in the kinetic stability studies for sufficiently large ion Larmor radius in comparison to the characteristic dimension.
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