Bootstrap current during perpendicular neutral injection in JT-60

Kikuchi, M.; Azumi, M.; Tsuji, S.; Tani, K.; Kubo, H.

doi:10.1088/0029-5515/30/2/012

Cited by 106 publications

(57 citation statements)

References 14 publications

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“…Details of TOPICS are shown in Ref. [14,15]. In this paper, thermal diffusivities are assumed as e,i = neo,i + ano,e,i , where neo,i denotes the neoclassical ion diffusivity calculated by the matrix inversion method [14], which also calculates the bootstrap current.…”

Section: 5d Transport Code Topicsmentioning

confidence: 99%

Integrated simulation of ELM energy loss determined by pedestal MHD and SOL transport

Hayashi¹,

Takizuka²,

Ozeki³

et al. 2007

Nucl. Fusion

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Abstract. An integrated simulation code TOPICS-IB based on a transport code with a stability code for the peeling-ballooning modes and a scrape-off-layer (SOL) model has been developed to clarify self-consistent effects of edge localized modes (ELMs) and SOL on the plasma performance. Experimentally observed collisionality dependence of the ELM energy loss is found to be caused by both the edge bootstrap current and the SOL transport. The bootstrap current decreases with increasing the collisionality and intensifies the magnetic shear at the pedestal region. The increase of the magnetic shear reduces the width of eigenfunctions of unstable modes, which results in the reduction of the area and the edge value near the separatrix of the ELM enhanced transport. On the other hand, when an ELM crash occurs, the energy flows into the SOL and the SOL temperature rapidly increases. The increase of the SOL temperature lowers the ELM energy loss due to the flattening of the radial edge gradient. The parallel electron heat conduction determines how the SOL temperature increases. For higher collisionality, the conduction becomes lower and the SOL electron temperature increases more. By the above two mechanisms, the ELM energy loss decreases with increasing the collisionality. The bootstrap current and the SOL transport have the major effect on the collisionality dependence.

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Section: 5d Transport Code Topicsmentioning

confidence: 99%

Integrated simulation of ELM energy loss determined by pedestal MHD and SOL transport

Hayashi¹,

Takizuka²,

Ozeki³

et al. 2007

Nucl. Fusion

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“…The bootstrap current is the neoclassical pressure driven current driven by the toroidal momentum transfer between trapped and passing particles, and has been confirmed in tokamak experiments. 66,67 Ideally, one would like to have a large bootstrap current fraction, maintained by the pressure gradient from the fusion alpha heating power, for economical tokamak/ST based power plant operation. The f BS can be expressed as…”

mentioning

confidence: 99%

Recent progress on spherical torus research

Ono

Kaita

2015

Physics of Plasmas

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The spherical torus or spherical tokamak (ST) is a member of the tokamak family with its aspect ratio (A = R0/a) reduced to A ∼ 1.5, well below the normal tokamak operating range of A ≥ 2.5. As the aspect ratio is reduced, the ideal tokamak beta β (radio of plasma to magnetic pressure) stability limit increases rapidly, approximately as β ∼ 1/A. The plasma current it can sustain for a given edge safety factor q-95 also increases rapidly. Because of the above, as well as the natural elongation κ, which makes its plasma shape appear spherical, the ST configuration can yield exceptionally high tokamak performance in a compact geometry. Due to its compactness and high performance, the ST configuration has various near term applications, including a compact fusion neutron source with low tritium consumption, in addition to its longer term goal of an attractive fusion energy power source. Since the start of the two mega-ampere class ST facilities in 2000, the National Spherical Torus Experiment in the United States and Mega Ampere Spherical Tokamak in UK, active ST research has been conducted worldwide. More than 16 ST research facilities operating during this period have achieved remarkable advances in all fusion science areas, involving fundamental fusion energy science as well as innovation. These results suggest exciting future prospects for ST research both near term and longer term. The present paper reviews the scientific progress made by the worldwide ST research community during this new mega-ampere-ST era.

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“…Observation of a high bootstrap current fraction, up to 80% in the JT-60 high-β p discharges [73] stimulated the design development of a SSTR, consistent with updated scientific and technological knowledge at that time [5]. [7].…”

Section: The Steady State Tokamak Reactormentioning

confidence: 61%

“…Nature blesses human being by providing an interesting physical process, called "bootstrap current" to make tokamaks operate in steady-state [71,72]. The bootstrap current is driven by the collisional relaxation of a distorted velocity distribution function in a rare collision regime (called collisionless plasma), which is a kind of thermo EMF that drives the plasma current in a toroidal direction and 80% of the plasma current is thus driven by the bootstrap current, as shown in Figure 7 [73]. The physics of non-inductive current drive are governed by the collisional transport along the magnetic field.…”

Section: Tokamak Continuous Operationmentioning

confidence: 99%

See 1 more Smart Citation

A Review of Fusion and Tokamak Research Towards Steady-State Operation: A JAEA Contribution

Kikuchi

2010

Energies

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Providing a historical overview of 50 years of fusion research, a review of the fundamentals and concepts of fusion and research efforts towards the implementation of a steady state tokamak reactor is presented. In 1990, a steady-state tokamak reactor (SSTR) best utilizing the bootstrap current was developed. Since then, significant efforts have been made in major tokamaks, including JT-60U, exploring advanced regimes relevant to the steady state operation of tokamaks. In this paper, the fundamentals of fusion and plasma confinement, and the concepts and research on current drive and MHD stability of advanced tokamaks towards realization of a steady-state tokamak reactor are reviewed, with an emphasis on the contributions of the JAEA. Finally, a view of fusion energy utilization in the 21st century is introduced.

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Bootstrap current during perpendicular neutral injection in JT-60

Cited by 106 publications

References 14 publications

Integrated simulation of ELM energy loss determined by pedestal MHD and SOL transport

Integrated simulation of ELM energy loss determined by pedestal MHD and SOL transport

Recent progress on spherical torus research

A Review of Fusion and Tokamak Research Towards Steady-State Operation: A JAEA Contribution

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