Modelling of the penetration process of externally applied helical magnetic perturbation of the DED on the TEXTOR tokamak

Kikuchi, Yusuke; Finken, K.H.; Jakubowski, M.; Lehnen, M.; Reiser, D.; Sewell, Granville; Wolf, R. C.

doi:10.1088/0741-3335/48/2/001

Cited by 31 publications

(43 citation statements)

References 38 publications

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“…The results are in good agreement with the experiment [15]. The calculated force transfer to the plasma is maximum when the resonance condition is fulfilled.…”

Section: Dependence Of the Error Field Penetration On Plasma Rotationsupporting

confidence: 86%

Tearing mode physics studies applying the dynamic ergodic divertor on TEXTOR

Koslowski

Westerhof

Bock

et al. 2006

Plasma Phys. Control. Fusion

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The dynamic ergodic divertor (DED) on the TEXTOR tokamak allows for the reproducible destabilization of the m/n = 2/1 tearing mode which is phase locked to the external static or rotating perturbation field. In combination with its flexible heating systems (co-and counter-neutral beam injection, ion cyclotron resonance heating, electron cyclotron resonance heating (ECRH) with steerable launcher) dedicated experiments to study the mode onset, properties of large islands and mode stabilization can be performed. The dependence of the mode excitation threshold (field penetration) on the plasma rotation shows a resonance character, with minimum threshold when the external perturbation frequency matches the MHD frequency of the 2/1 mode. Mode stabilization by ECRH heating shows that for the TEXTOR plasma heating is more effective than the current drive in O-point. Extrapolation to ITER yields a significant contribution to the mode suppression originating from the temperature increase within the island. Alfvén-like modes, which have been previously identified in the vicinity of large islands on FTU (Buratti et al 2005 Nuclear Fusion 45 1446), are found to be created already before island formation above a certain threshold of the externally applied perturbation field.3 Members in the Trilateral Euregio Cluster (TEC).

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“…The results are in good agreement with the experiment [15]. The calculated force transfer to the plasma is maximum when the resonance condition is fulfilled.…”

Section: Dependence Of the Error Field Penetration On Plasma Rotationsupporting

confidence: 86%

Tearing mode physics studies applying the dynamic ergodic divertor on TEXTOR

Koslowski

Westerhof

Bock

et al. 2006

Plasma Phys. Control. Fusion

Self Cite

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“…The above phenomenology of the LMO is in qualitative agreement with MHD theory, which shows that the suppression of the island is associated with singular currents flowing near the resonant surface [43,44,45,46,41,47,48]. The bifurcation occurs when the viscous force on the resonant layer, which acts to maintain the rotation, can no longer balance the electromagnetic braking force created by the RMP.…”

Section: Onset Of Locked Modessupporting

confidence: 75%

Role of singular layers in the plasma response to resonant magnetic perturbations

et al. 2012

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Abstract. The response of an H-mode plasma to magnetic perturbations that are resonant in the edge is evaluated using a fluid model. With two exceptions, the plasma rotation suppresses the formation of magnetic islands, holding their widths to less than a tenth of those predicted by the vacuum approximation. The two exceptions are at the foot of the pedestal, where the plasma becomes more resistive, and at the surface where the perpendicular component of the electron velocity reverses. The perturbations exert a force on the plasma that is such as to brake the perpendicular component of the electron rotation. In the pedestal, the corresponding Maxwell stress drives the radial electric field in such a way as to accelerate ion rotation. Despite the suppression of the islands, the perturbations give rise to particle fluxes caused by magnetic flutter, with a negligible contribution from E×B convection. In the pedestal, the fluxes are such as to reduce the density.

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“…In general case, the stability index components C Δ and S Δ are found separately for both the cosine and sine space harmonics of the flux function similar to [2,3,5]. Without RMP, CS ΔΔ ,   one can obtain from (10), (13) - (16) In the model used for the TEAR code numerical calculations, we apply the factor  at the first terms in the right-hand side of equations (13), (14) in accordance with [2,9]. In this model we also supplement the equations (13), (14) with the neoclassical term and the term for the electron diamagnetic drift:…”

Section: Computational Modelmentioning

confidence: 99%

Magnetic Island Dynamics Under External Magnetic Perturbation in Rotating Resistive Iter Plasma

Ivanov¹,

Kakurin²,

Коновалов³

2013

PAST-TF

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The modeling of the magnetic island evolution under resonant magnetic perturbations, RMP, in rotating ITER-like plasma from seed island initial generation, through appearance and development of the NTM till its locking and saturation is presented. The effects of plasma resistivity, viscosity, diamagnetic drift and the effect of the currents induced in the resistive vacuum vessel wall are taken into account. The calculations are carried out with the TEAR code based on the non-linear modified Rutherford model. The dependence of the tearing mode stability index on the angular position of the mode with respect to the RMP is taken into account. It results in deviations of the magnetic island rotation velocity from the velocity of the plasma layer in the vicinity of the rational magnetic surface. The magnetic island dynamics under RMP is analyzed for the modes originated at the q = 3/2 and q = 2 magnetic surfaces. The NTM behavior is discussed for cases of the seed island generation by different RMP sources including the coils for mitigation of the edge localized modes, ELMs.Key words: tokamak, plasma, magnetic island, resonant magnetic perturbation, error field, neoclassical tearing mode. ДИНАМИКА МАГНИТНЫХ ОСТРОВОВ ВО ВРАЩАЮЩЕЙСЯ РЕЗИСТИВНОЙ ПЛАЗМЕ ИТЭР В ПРИСУТСТВИИ ВНЕШНИХ ВОЗМУЩЕНИЙ МАГНИТНОГО ПОЛЯ Н.В. Иванов, А.М. Какурин, С.В. Коновалов НИЦ «Курчатовский институт», Москва, РоссияДанная работа посвящена моделированию эволюции магнитных островов под действием резонансного магнитного возмущения (РМВ) во вращающейся плазме на стадиях возбуждения исходного магнитного острова, возникновения и развития неокласси-ческой тиринг-моды (НТМ), а также её захвата и насыщения. При моделировании учитываются эффекты резистивности и вяз-кости плазмы, диамагнитного дрейфа и влияния токов, индуцированных в резистивной стенке вакуумной камеры. Вычисления выполняются с помощью кода TEAR, базирующегося на нелинейной модифицированной модели Резерфорда. В расчётах учи-тывается зависимость индекса устойчивости тиринг-моды от углового положения моды по отношению к РМВ. Это приводит к отклонениям скорости вращения магнитных островов от скорости слоя плазмы в окрестности резонансной магнитной поверх-ности. В предлагаемой работе проводится анализ динамики магнитных островов на магнитных поверхностях q = 3/2 и q = 2 под действием РМВ. Обсуждаются динамика и возможности подавления НТМ в ИТЭР для случаев генерации исходных островов различными источниками РМВ, включая обмотки для управления неустойчивостью ELM.Ключевые слова: токамак, плазма, магнитный остров, резонансное магнитное возмущение, паразитное магнитное поле, неоклассическая тиринг-мода.

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Modelling of the penetration process of externally applied helical magnetic perturbation of the DED on the TEXTOR tokamak

Cited by 31 publications

References 38 publications

Tearing mode physics studies applying the dynamic ergodic divertor on TEXTOR

Tearing mode physics studies applying the dynamic ergodic divertor on TEXTOR

Role of singular layers in the plasma response to resonant magnetic perturbations

Magnetic Island Dynamics Under External Magnetic Perturbation in Rotating Resistive Iter Plasma

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