Identification of edge-localized moments of the current density profile in a tokamak equilibrium from external magnetic measurements

Carthy, P. J. Mc

doi:10.1088/0741-3335/54/1/015010

Cited by 77 publications

(95 citation statements)

References 23 publications

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“…6, the measured diamagnetic flux is compared to that predicted by the TRANSP simulation for a discharge with neutral beam and electron cyclotron heating. The poloidal beta inferred from the diamagnetic flux measurement, 19 β DIA , is in good agreement with the values calculated from the real-time 20,21 and offline magnetic equilibrium reconstruction codes, β MHD , in the steady state phase of the discharges. In the discharge with electron cyclotron heating, the increase in poloidal beta with time is due to a steady increase in the nitrogen seeding introduced for reduction of the heat load to the divertor target.…”

Section: Transp Simulationssupporting

confidence: 77%

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Real-time diamagnetic flux measurements on ASDEX Upgrade

Giannone

Geiger

Bilato

et al. 2016

Review of Scientific Instruments

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Author(s)Giannone, L.; Geiger, B.; Bilato, R.; Maraschek, M.; Odstrčil, T.;Fischer, R.; Fuchs, J. C.; McCarthy, Patrick J.; Mertens, V.; Schuhbeck, K. H. Publication date 2016-05-24Original citation Giannone, L., Geiger, B., Bilato, R., Maraschek, M., Odstrčil, T., Real-time diamagnetic flux measurements are now available on ASDEX Upgrade. In contrast to the majority of diamagnetic flux measurements on other tokamaks, no analog summation of signals is necessary for measuring the change in toroidal flux or for removing contributions arising from unwanted coupling to the plasma and poloidal field coil currents. To achieve the highest possible sensitivity, the diamagnetic measurement and compensation coil integrators are triggered shortly before plasma initiation when the toroidal field coil current is close to its maximum. In this way, the integration time can be chosen to measure only the small changes in flux due to the presence of plasma. Two identical plasma discharges with positive and negative magnetic field have shown that the alignment error with respect to the plasma current is negligible. The measured diamagnetic flux is compared to that predicted by TRANSP simulations. The poloidal beta inferred from the diamagnetic flux measurement is compared to the values calculated from magnetic equilibrium reconstruction codes. The diamagnetic flux measurement and TRANSP simulation can be used together to estimate the coupled power in discharges with dominant ion cyclotron resonance heating.[http://dx

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Section: Transp Simulationssupporting

confidence: 77%

“…The position of the separatrix is determined by the offline ASDEX Upgrade magnetic equilibrium reconstruction code, CLISTE. 19 However, in contrast to CLISTE, TRANSP simulates the fast-ion distribution function which has an impact on the diamagnetic flux. Therefore TRANSP is the appropriate tool for the following comparisons.…”

Section: Transp Simulationsmentioning

confidence: 99%

Real-time diamagnetic flux measurements on ASDEX Upgrade

Giannone

Geiger

Bilato

et al. 2016

Review of Scientific Instruments

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“…∆B/BM SE = 1.59% In order to validate the forward model, a reference discharge has been conducted on ASDEX Upgrade. The discharge parameter were chosen to reflect conditions which have been analysed with the CLISTE equilibrium code 25,44 . Fig.…”

Section: Effect Of Atomic Extension Onto Experimental Quantitiesmentioning

confidence: 99%

“…The recently developed MSE forward model 24 is extended and takes the Zeeman-Stark effect and the spin-orbit coupling into account in order to describe the measured MSE spectra. Finally, the results of the measurements are compared with results from equilibrium solver (CLISTE ) 25 for ASDEX Upgrade experimental conditions.…”

mentioning

confidence: 99%

Influence of non-local thermodynamic equilibrium and Zeeman effects on magnetic equilibrium reconstruction using spectral motional Stark effect diagnostic

Reimer

Marchuk

Geiger

et al. 2017

Review of Scientific Instruments

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“…Методы решения такой некорректно поставленной задачи основываются на следующих подходах: разложение по тороидальным гармоникам [6], использование филаментов (точечных или распределён-ных, подвижных или стационарных) [7][8][9][10], решение интегральных уравнений [5,11,12]. В настоящей работе применяется метод, основанный на интегральных уравнениях, который ранее применялся при моделировании системы магнитной диагностики установки КТМ (Казахстан) [11].…”

Section: система электромагнитной диагностики модернизированной устанunclassified

Numerical Simulation of Electromagnetic Diagnostics System of the Tokamak T-15

Zotov¹,

Белов²,

Sychugov³

et al. 2015

PAST-TF

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В настоящее время проводится модернизация токамака Т-15. Одной из задач исследований на Т-15 является получение разря-дов с вытянутым поперечным сечением плазмы, окружённым сепаратрисой. Присутствие на сепаратрисе Х-точки, где магнит-ное поле обращается в ноль, позволяет использовать данную конфигурацию для создания дивертора -устройства для вывода из плазмы примесей и продуктов реакции. Для оптимизации дивертора и контроля плазмы предполагается в каждый момент разряда проводить реконструкцию границы плазменного шнура. Достоверность такой реконструкции зависит от влияния раз-личных факторов на сигналы электромагнитной диагностики. В работе на основе одного из возможных сценариев разряда в Т-15 проведено исследование точности реконструкции границы плазмы и профиля тока в зависимости от погрешности измере-ний и прочих факторов. Рассматривается задача определения границы плазмы на лимитерной и диверторной стадиях разряда, исследуется влияние распределения тока на сигналы в магнитных датчиках. Так как подобная задача является некорректной, изучается вопрос о выборе параметра регуляризации, в частности, когда погрешность измерений неизвестна. Входными дан-ными задачи являются число магнитных датчиков и их расположение, а также погрешность измерения ими магнитных полей. Исследуется точность восстановления границы плазмы в целом и X-точки сепаратрисы отдельно в зависимости от погрешности измерений и количества датчиков. Моделирование сценария разряда проводилось с помощью кодов TOKAMEQ и DINA. Об-ратные задачи МГД-равновесия решались на основе кода RPB (Reconstruction of Plasma Boundary).Ключевые слова: токамак Т-15, обратная задача МГД-равновесия, электромагнитная диагностика, граница плазмы, профиль тока. The T-15 Tokamak is now under modernisation. One of the objectives of research in the T-15 is obtaining a discharge with an elongated cross-section of the plasma, surrounded with a separatrix. The presence of Х-point on the separatrix, where the magnetic field vanishes, allows to create a divertor-the device for removal of plasma impurities and reaction products. In order to optimize and control the divertor plasma is expected at every moment of the discharge to carry out the reconstruction of the plasma boundary. Reliability of this reconstruction depends on the influence of various factors on the electromagnetic signals of diagnostics. In this paper on the basis of one of the possible scenarios discharge in the T-15 we are interested in the plasma boundary reconstruction accuracy and current profile according to the measurement error and other factors. The problem of determining the plasma boundary on the limiter and divertor discharge stage is studied, examines the impact of the plasma current density at the signals of the magnetic sensors. As this problem is illposed, we study choosing the regularization parameter, in particular for the case when the measurement error is unknown. The problem input data are the number of magnetic sensors and their location and the accuracy of the magnetic fields measurement. We s...

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Identification of edge-localized moments of the current density profile in a tokamak equilibrium from external magnetic measurements

Cited by 77 publications

References 23 publications

Real-time diamagnetic flux measurements on ASDEX Upgrade

Real-time diamagnetic flux measurements on ASDEX Upgrade

Influence of non-local thermodynamic equilibrium and Zeeman effects on magnetic equilibrium reconstruction using spectral motional Stark effect diagnostic

Numerical Simulation of Electromagnetic Diagnostics System of the Tokamak T-15

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