Mirnov coil data analysis for tokamak ADITYA

Raju, D.; Jha, Ratneshwar; Kaw, P. K.; Mattoo, S. K.; Saxena, Y. C.; Team, Aditya

doi:10.1007/s12043-000-0039-8

Cited by 28 publications

(21 citation statements)

References 5 publications

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“…C +4 ) impu rity is measured by the multichannel spectrometer [34] in the range of r/a = 0.65-1. The m/n = 2/1 TM is measured by poloidal and toroidal Mirnov arrays and identified from the temporal evolution of the Mirnov signals using singular value decomposition (SVD) technique [35]. The locked mode detectors consist of two sets of saddle loops.…”

Section: Methodsmentioning

confidence: 99%

Effect of electrode biasing on m/n = 2/1 tearing modes in J-TEXT experiments

Liu

Chen

et al. 2016

Nucl. Fusion

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The effects of electrode biasing (EB) on the m/n = 2/1 tearing mode have been experimentally studied in J-TEXT tokamak discharges, where m and n are the poloidal and toroidal mode numbers. It is found that for a negative bias voltage, the mode amplitude is reduced, and the mode frequency is increased accompanied by the increased toroidal plasma rotation speed in the counter-I p direction. For a positive bias voltage, the mode frequency is decreased together with the change of the rotation velocity towards the co-I p direction, and the mode amplitude is increased. Statistic results show that the variations in the toroidal rotation speed, the 2/1 mode frequency and its amplitude linearly depend on the bias voltage. The threshold voltages for complete suppression and locking of the mode are found. The experimental results suggest that applied electrode biasing is a possible method for the avoidance of mode locking and disruption.

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Section: Methodsmentioning

confidence: 99%

Effect of electrode biasing on m/n = 2/1 tearing modes in J-TEXT experiments

Liu

Chen

et al. 2016

Nucl. Fusion

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“…The schematic of the LVF application is shown in figure1.The main set of diagnostics used in these experiments includes external magnetic sensors to measure loop voltage (V loop ), plasma current (I P ) and plasma position. The MHD oscillations are measured by a garland of 16 Mirnov coils distributed at equal angular separations in the poloidal direction at a single toroidal location[24]. Eight-channel microwave interferometer is used for line average electron density (n e ) measurements.…”

mentioning

confidence: 99%

Novel approaches for mitigating runaway electrons and plasma disruptions in ADITYA tokamak

Tanna¹,

Ghosh²,

Chattopadhyay³

et al. 2015

Nucl. Fusion

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This paper summarizes the results of recent dedicated experiments on disruption control and runaway mitigation carried out in ADITYA, which are of the utmost importance for the successful operation of large size tokamaks, such as ITER. It is quite a well-known fact that disruptions in tokamaks must be avoided. Disruptions, induced by hydrogen gas puffing, are successfully avoided by two innovative techniques in ADITYA using a bias electrode placed inside the last closed flux surface and applying an ion cyclotron resonance pulse with a power of ∼50 to 70 kW. These experiments led to better understanding of the disruption avoidance mechanisms and also can be thought of as one of the options for disruption avoidance in ITER. In both cases, the physical mechanism seems to be the control of magnetohydrodynamic modes due to increased poloidal rotation of edge plasma generated by induced radial electric fields. Real time avoidance of disruption with identifying proper precursors in both the mechanisms is successfully attempted. Further, analysing thoroughly the huge database of different types of spontaneous and deliberately-triggered disruptions from ADITYA, a significant contribution has been made to the international disruption database (ITPA). Furthermore, the mitigation of the runaway electron generated mainly during disruptions remains a challenging topic in present tokamak research as these high-energy electrons can cause severe damage to in-vessel components and the vacuum vessel. A simple technique has been implemented in ADITYA to mitigate the runaway electrons before they can gain high energies using a localized vertical magnetic field perturbation applied at one toroidal location to extract runaway electrons.

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“…In the above expression, V is M×N orthonormal matrix (M being the channels and N data points), U is an M×M orthonormal matrix and S, is an M×M diagonal matrix. [5][6][7][8] Matlab was employed to run the relevant algorithm and the SVD and polar graphs are presented in the last section.…”

Section: Singular Value Decomposition (Svd)mentioning

confidence: 99%

The toroidal magnetic field correction to reduce instabilities through current rise up phase in IR-T1 tokamak

Riazifar¹,

Meshkani²,

Moghaddam³

et al. 2019

PAIJ

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Keeping the plasma stable throughout the plasma discharge is now considered a massive undertaking in today’s Tokamaks. In this study, the part that the current rise up phase plays in the total plasma stability was investigated, toroidal magnetic field on IR-T1 Tokamak was altered to reach the least amount of instabilities in current rise up phase. In this experiment, in order to provide rigorous and details affirmation, SVD, FFT and hard X-ray analyses were employed. The results state that with toroidal magnetic field increment to a specific amount (3.10 KV), the plasma experiences the least amount of Mirnov oscillations (almost 25%) and instabilities during current rise up phase.

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Mirnov coil data analysis for tokamak ADITYA

Cited by 28 publications

References 5 publications

Effect of electrode biasing on m/n = 2/1 tearing modes in J-TEXT experiments

Effect of electrode biasing on m/n = 2/1 tearing modes in J-TEXT experiments

Novel approaches for mitigating runaway electrons and plasma disruptions in ADITYA tokamak

The toroidal magnetic field correction to reduce instabilities through current rise up phase in IR-T1 tokamak

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