Estimation of Plasma Elongation and Position on Noncircular Tokamak TRIAM-1M

Moriyama, S.; Nakamura, K.; Shoji, K.; Jotaki, E.; Nagao, Akihiro; Nakamura, Yukio; Hiraki, Naoji; Itoh, Susumu

doi:10.1143/jjap.28.1479

Cited by 8 publications

(5 citation statements)

References 5 publications

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“…For our discussion it is important that the field B pl measured outside the plasma carries information about its boundary but nothing more. This is the reason why the problems of determining the position and shape of the plasma from externally measured magnetic signals are successfully solved both for tokamaks [58][59][60][61][62] and for stellarators [37,38,63]. Very good accuracy is achieved in practice, and knowledge of p(r) and j(r) is not required for this.…”

Section: Discussionmentioning

confidence: 99%

Magnetic diagnostics: General principles and the problem of reconstruction of plasma current and pressure profiles in toroidal systems

Pustovitov

2001

Nucl. Fusion

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Restrictions on magnetic diagnostics are discussed. Being related to the integral nature of the measurable quantities, these follow from the fundamental laws of electromagnetism. A series of examples demonstrating the strength of these restrictions is analysed. The general rule is emphasized that information obtained from external magnetic measurements is insufficient for reliable evaluation of plasma current and pressure profiles in tokamaks and in stellarators. The underlying reason is that outside the plasma the self-field of the equilibrium plasma currents is determined by the boundary conditions on the plasma surface alone.

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Section: Discussionmentioning

confidence: 99%

Magnetic diagnostics: General principles and the problem of reconstruction of plasma current and pressure profiles in toroidal systems

Pustovitov

2001

Nucl. Fusion

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“…The plasma position (vertical ∆z and horizontal ∆R = R − R 0 ) is feedback controlled [9]. Here ∆z = 0 means midplane.…”

Section: Lhcd Plasma and System Hardwarementioning

confidence: 99%

Recent progress on TRIAM-1M

et al. 2000

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A steady state plasma with high performance and high current drive efficiency is reported. In 2.45 GHz LHCD plasmas Ti is studied as a function of ne at the edge of the high ion temperature (HIT) window. Different characteristic timescales are found for Ti and ne to enter the HIT regime and the observed hysteresis behaviour of Ti with respect to ne is attributed to this difference. The electromagnetic emission (<3.5 GHz) is studied in order to understand ion heating mechanisms in the HIT regime. The spectrum shows several sidebands whose peak frequencies correspond to the ion plasma frequency. The spectral narrowing of the width of the sideband shows a clear correlation with ion heating. In 8.2 GHz LHCD plasmas an enhanced current drive (ECD) regime where both current drive efficiency ηCD( = n̄eICDR0/PLH ∼1 × 1019 A m-2/W) and energy confinement time τE (∼8-10 ms) are simultaneously improved is obtained at an n̄e of 4.3 × 1013 cm-3 and B = 7 T under full current drive conditions. There exists a certain threshold power above which the ECD transition occurs. A hysteresis of ηCD is found around the threshold power, which is explained by the different characteristic time for the ECD transition in power rampup and rampdown schemes. Current profile control experiments are performed by using two opposite travelling LHWs. Current compensation (ΔICD/ICD < -10%) is clearly seen when the backward (BW) travelling LHW (8.2 GHz) is added to a target plasma whose current is driven by a forward travelling LHW (8.2 GHz). As the BW wave power is increased, however, the current tends to flow in the forward direction. The mechanisms of this non-linear behaviour of the driven current with respect to the BW wave power are discussed.

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“…This is the reason why the problems of determining the position and shape of the plasma from externally measured magnetic signals are successfully solved both for tokamaks [58][59][60][61][62] and for stellarators [37,38,63]. Very good accuracy is achieved in practice, and knowledge of p(r) and j(r) is not required for this.…”

Section: Resultsmentioning

confidence: 99%

Surface Morphology of Tl₂Ba₂Ca₂Cu₃O_y Thin Films Prepared by Thallium Diffusion Process

Adachi¹,

Adachi²,

Ichikawa³

et al. 1991

Jpn. J. Appl. Phys.

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Estimation of Plasma Elongation and Position on Noncircular Tokamak TRIAM-1M

Cited by 8 publications

References 5 publications

Magnetic diagnostics: General principles and the problem of reconstruction of plasma current and pressure profiles in toroidal systems

Magnetic diagnostics: General principles and the problem of reconstruction of plasma current and pressure profiles in toroidal systems

Recent progress on TRIAM-1M

Surface Morphology of Tl₂Ba₂Ca₂Cu₃O_y Thin Films Prepared by Thallium Diffusion Process

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Estimation of Plasma Elongation and Position on Noncircular Tokamak TRIAM-1M

Cited by 8 publications

References 5 publications

Magnetic diagnostics: General principles and the problem of reconstruction of plasma current and pressure profiles in toroidal systems

Magnetic diagnostics: General principles and the problem of reconstruction of plasma current and pressure profiles in toroidal systems

Recent progress on TRIAM-1M

Surface Morphology of Tl2Ba2Ca2Cu3Oy Thin Films Prepared by Thallium Diffusion Process

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Surface Morphology of Tl₂Ba₂Ca₂Cu₃O_y Thin Films Prepared by Thallium Diffusion Process