Model of the H-mode in tokamaks

Itoh, Sanae I.; Itoh, K.

doi:10.1088/0029-5515/29/6/013

Cited by 151 publications

(136 citation statements)

References 45 publications

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“…For the ion temperature of T i ∼ 200 eV, the normalized radial electric field satisfies the relation eρ p E r /T i ∼ −1. This magnitude is close to the condition where the bifurcation of radial electric field can occur [2,[64][65][66]. Along this line of thought, an emphasis is made on the importance of ion pressure gradient in [63].…”

Section: Critical Condition For the Onset Of Transitionmentioning

confidence: 62%

An Assessment of Limit Cycle Oscillation Dynamics Prior to L-H Transition

Itoh

Fujisawa

2013

Plasma and Fusion Research

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In this article, experimental observations of limit cycle oscillations (LCO) that precede L-to-H transition are discussed. Issues are: (1) the existence of zonal flows, (2) spatio-temporal evolutions of turbulence intensity, and (3) periodic generations/decays of mean radial electric field and density. The role of Reynolds stress to accelerate the LCO flow is also addressed. The propagation of changes of the density gradient and turbulence amplitude into the core is commented. Varieties in experimental reports on these issues are explained, and possible origins of different interpretations are discussed. Problem definitions for the future research for resolution are presented.

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Section: Critical Condition For the Onset Of Transitionmentioning

confidence: 62%

An Assessment of Limit Cycle Oscillation Dynamics Prior to L-H Transition

Itoh

Fujisawa

2013

Plasma and Fusion Research

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“…1 In particular, the formation of transport barriers in high-confinement mode ͑H mode͒ toroidal plasmas 2 has been the focus of numerous researches. Key mechanisms to understand the H-mode transition include bifurcation of the electric field 3,4 and the associated suppression of turbulence by electric-field structures. 5,6 Thus significant attention has been devoted to studying the steep radial electric-field structure in the low to high confinement mode ͑L / H͒ transition physics.…”

Section: Introductionmentioning

confidence: 99%

Convective particle transport arising from poloidal inhomogeneity in tokamak H mode

Kasuya

Itoh

2005

Physics of Plasmas

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In tokamak high-confinement modes ͑H modes͒, a large poloidal flow exists within an edge transport barrier, and the electrostatic potential and density profiles can be steep both in the radial and poloidal directions. The two-dimensional structures of the electrostatic potential, density, and flow velocity near the edge of a tokamak plasma are investigated. The analysis is carried out with the momentum conservation law using the shock ordering. For the case with a strong radial electric field ͑H-mode case͒, a particle flux is induced from asymmetry of the poloidal electric field in the transport barrier. This convective transport is found to depend weakly on collisionality, and changes its direction in accordance with the direction of the radial electric field, the toroidal magnetic field, and the plasma current. The divergence of a particle flux is a source of temporal variation of the density, and there are negative divergence regions both in the inward and outward flux cases. Thus this convective particle flux is a new candidate for the cause of the rapid establishment of the density pedestal after the onset of low to high confinement mode ͑L / H͒ transition.

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“…The concept of NEI is relatively simple [9,15,16]. NEI is important in supernova remnants as in the relatively recently heated plasmas the ions have not had sufficient time to ionize up to the ionization level at which the number of ionizations is compensated by the number of recombinations (i.e.…”

Section: Introductionmentioning

confidence: 99%

High Resolution X-ray Spectroscopy of SN 1006

Vink¹

2005

AIP Conference Proceedings

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Abstract. I discuss the high resolution XMM-Newton Reflection Grating Spectrometer (RGS) spectrum of SN 1006. SN 1006 is one of the best examples of a supernova remnant that is far out of ionization equilibrium. Moreover, optical, UV and X-ray data indicate that it is also out of temperature equilibrium. I discuss the X-ray evidence for this.In addition I discuss the lower resolution RGS spectrum of the eastern rim of SN 1006. Despite the lower resolution, the spectrum contains significant evidence for an asymmetric expansion velocity. Two likely solutions fit the O VII triplet. One with no significant thermal broadening and a shell velocity of ∼ 6500 km s −1 , and one with significant broadening and a shell velocity of 9500 km s −1 . The first solution seems the most plausible, as it is consistent with radio expansion measurements, which suggest a decelerated shell.

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Model of the H-mode in tokamaks

Cited by 151 publications

References 45 publications

An Assessment of Limit Cycle Oscillation Dynamics Prior to L-H Transition

An Assessment of Limit Cycle Oscillation Dynamics Prior to L-H Transition

Convective particle transport arising from poloidal inhomogeneity in tokamak H mode

High Resolution X-ray Spectroscopy of SN 1006

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