Ion thermal conductivity and ion distribution function in the banana regime

Taguchi, Masayoshi

doi:10.1088/0741-3335/30/13/009

Cited by 37 publications

(27 citation statements)

References 12 publications

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“…The constant M can then be taken to be independent of velocity, but it has later emerged that allowing M to depend on v is necessary for obtaining results that are reasonably accurate when the trapped-particle fraction is finite [8,11,12]. For our purposes it is important that the calculation can be divided into two steps: first the kinetic equation (4) is solved without the momentumrestoring term, and in a second step the solution to the equation with M = 0 can be found without solving another differential equation [13,14].…”

Section: Adjoint Equationmentioning

confidence: 99%

On the bootstrap current in stellarators and tokamaks

2011

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The expression for the long-mean-free-path limit of the bootstrap current in stellarators is rederived in such a way that the expansion procedure is identical to that used in the corresponding calculation for a tokamak. In addition, the first correction due to finite collisionality is calculated and shown to vanish in quasi-isodynamic configurations without net current. This correction, which is proportional to the square root of the collisionality, is found to compare well with a numerical solution of the first-order drift kinetic equation in spherical tokamak geometry. Numerically, it appears that there is a similar correction in general stellarator geometry, which however depends on the strength of the radial electric field.

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Section: Adjoint Equationmentioning

confidence: 99%

On the bootstrap current in stellarators and tokamaks

2011

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“…This approach is important for the reformulation of the parallel viscosity as the friction of passing with trapped particles and, consequently, will be briefly described here following Refs. [16,17]. The particle species index .…”

Section: Momentum Balance In the Collisionless Asymptotic Limitmentioning

confidence: 99%

Momentum correction techniques for neoclassical transport in stellarators

Maaßberg¹,

Beidler²,

Turkin³

2009

Physics of Plasmas

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In the traditional neoclassical ordering for stellarators, mono-energetic transport coefficients are evaluated using the simplified Lorentz form of the pitch-angle collision operator which violates momentum conservation. In this paper, the parallel momentum balance with radial parallel momentum transport and viscosity terms is analysed, in particular with respect to the radial electric field. Next, the impact of momentum conservation in the stellarator lmfp-regime is estimated for the radial transport and the parallel electric conductivity. Two different momentum correction techniques are described based on mono-energetic transport coefficients calulated by the DKES code [W.I. van Rij and S.P. Hirshman, Phys. Fluids B 1, 563 (1989)]. The benchmarking of the parallel electric conductivity and of the bootstrap current is presented for a tokamak as well as for two W7-X stellarator configurations [G. Grieger et al., Phys. Fluids B 4, 2081(1992]. Finally, the impact of the momentum correction on the expected total bootstrap current is briefly analysed for two W7-X scenarios.

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“…In intermediate regions, approximate expressions must be used. The most accurate such analytical expression in the literature is [20,27] …”

Section: Banana Regimementioning

confidence: 99%

“…This calculation can be done relatively easily in the case of a pure plasma, as in Refs. [20,27]. If the plasma contains impurities, the calculation is more difficult but has recently been carried out with the result [28]…”

Section: Banana Regimementioning

confidence: 99%

Controlling edge plasma rotation through poloidally localized refueling

2003

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The transport of angular momentum due to neutral atoms in the tokamak edge is calculated and shown to be sensitive to the poloidal location of the neutrals. In the absence of external momentum sources, the edge plasma is predicted to rotate spontaneously in the opposite direction to the plasma current, at a speed proportional to the radial ion temperature gradient. If the plasma is collisional, this counter-current rotation is largest if the neutrals are concentrated on the inboard side of the torus, while the opposite holds in a collisionless plasma. The presence of heavy impurity ions also promotes counter-current rotation. The rotation caused by an external momentum source, such as neutral-beam injection, is found to be larger when the neutrals are on the inboard rather than the outboard side.

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Ion thermal conductivity and ion distribution function in the banana regime

Cited by 37 publications

References 12 publications

On the bootstrap current in stellarators and tokamaks

On the bootstrap current in stellarators and tokamaks

Momentum correction techniques for neoclassical transport in stellarators

Controlling edge plasma rotation through poloidally localized refueling

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