Real-time feedback control system for ADITYA-U horizontal plasma position stabilisation

Kumar, Rohit; Gautam, Pramila; Gupta, Sakshi; Tanna, R.L.; Edappala, Praveenlal; Shah, Minsha; Raulji, Vismay; Jadeja, K. A.; Patel, Kiran; Macwan, Tanmay; Manchanda, R.; Chowdhuri, M. B.; Yadava, Nandini; Shah, Kunal; Makwana, M.; Balakrishnan, V.; Gupta, C.N.; Aich, Suman; Kumawat, Devilal; Raj, Harshita; Sathyanarayana, K.; Ghosh, Joydeep; Rajpal, Rachna; Chattopadhyay, P. K.; Saxena, Y. C.

doi:10.1016/j.fusengdes.2020.112218

Cited by 7 publications

(5 citation statements)

References 20 publications

(26 reference statements)

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“…Microwave interferometer is used for electron density measurement [22] and electron temperature is deduced from the Soft X-ray emission measurement using foil-ratio technique [24]. PMT-filter based spectroscopic systems and visible spectrometers are used for Hα and low Z impurity emission monitoring as well as plasma column boundary position measurements [10,23]. VUV spectrometers are used for high Z impurity emission measurement [23].…”

Section: Aditya-u Operations and Experimental Progressmentioning

confidence: 99%

“…The ADITYA-U pulse power supply is used for powering the TF, TR, and BV coils. A dual-polarity fast feedback power supply (FFPS) controlled by proportional-integral-derivative (PID) controller is used for real-time horizontal plasma position control [10]. Details of associated electronics, the data acquisition and triggering transmitter and receiver systems of ADITYA-U were described in [1].…”

Section: Aditya-u Operations and Experimental Progressmentioning

confidence: 99%

“…This has led to a significant improvement in the plasma performance. Moreover, the efficient use of closed-loop real-time horizontal plasma position control [10] has led to substantial improvement in discharge consistency. The maximum plasma parameters achieved in the ohmically heated ADITYA-U limiter (toroidal belt-limiter) plasmas are I P ∼ 210 kA, discharge duration ∼ 400 ms, chord-averaged electron density ∼ 6 × 10 19 m −3 , central electron temperature ∼ 500 eV and stored energy ∼ 3 kJ.…”

Section: Introductionmentioning

confidence: 99%

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Overview of recent experimental results from the ADITYA-U tokamak

Tanna¹,

Macwan²,

Ghosh³

et al. 2022

Nucl. Fusion

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Since the 2018 IAEA-FEC conference, in addition to expanding the parameter horizons of the ADITYA-U machine, emphasis has been given to dedicated experiments on inductively driven particle injection (IPI) for disruption studies, runaway electron (RE) dynamics and mitigation, plasma rotation reversal, radiative-improved modes using Ne and Ar injection, modulation of magneto–hydrodynamic modes, edge turbulence using periodic gas puffs and electrode biasing (E-B). Plasma parameters close to the design parameters of circular plasmas with H2 and D2 as fuel have been realized, and the shaped plasma operation has also been initiated. Consistent plasma discharges having I P ∼ 100–210 kA, t ∼ 300–400 ms, n e ∼ 3–6 × 1019 m−3, core T e ∼ 300–500 eV were achieved with a maximum B T of ∼1.5 T. The enhanced plasma parameters are the outcome of repeated cycles of baking (135 °C), followed by extensive wall conditioning, which includes pulsed glow discharge cleaning in H, He and Ar–H mixture, and lithiumization. A higher confinement time has been observed in D2 compared to H2 plasmas. Furthermore, shaped plasmas are attempted for the first time in ADITYA-U. A first of its kind inductively driven particle injection for disruption mitigation studies has been developed and operated. The injection of solid particles into the plasma core leads to a fast current quench. Two pulses of electron cyclotron resonance wave at 42 GHz are launched in a single discharge: one pulse is used for pre-ionization and the second for heating. In a novel approach, a positively biased electrode is used to confine REs after discharge termination. E-B is also used for controlling the rotation of drift-tearing modes by changing the plasma rotation. Cold pulse propagation and signatures of detachment are observed during the injection of short gas puffs. A correlation between the plasma toroidal rotation and the total radiated power has been observed with neon gas injection-induced improved confinement modes.

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Section: Aditya-u Operations and Experimental Progressmentioning

confidence: 99%

Section: Aditya-u Operations and Experimental Progressmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Overview of recent experimental results from the ADITYA-U tokamak

Tanna¹,

Macwan²,

Ghosh³

et al. 2022

Nucl. Fusion

Self Cite

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“…A field-programmable gate array-based PID controller was used for the operation of the real-time position control system [27]. A model for the ADITYA-U horizontal plasma position control was implemented in a closed loop configuration.…”

Section: Real-time Plasma Position Control In Aditya-umentioning

confidence: 99%

Overview of operation and experiments in the ADITYA-U tokamak

et al. 2019

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First indigenously built tokamak ADITYA, operated over 2 decades with circular poloidal limiter has been upgraded to a tokamak named ADITYA Upgrade for the purpose having shape plasma operation with open divertor geometry. Experiment research in ADITYA-U has made significant progress, since last FEC 2016. After installation of PFC and standard tokamak diagnostics, the Phase-I plasma operations were conducted from December 2016 with graphite toroidal belt limiter. Purely Ohmic discharges in circular plasmas supported by Filament pre-ionization was obtained. The plasma parameters, Ip ~ 80-95 kA, duration ~ 80-180 ms with toroidal field (max.) ~ 1T and chord-averaged electron density ~ 2.5 x 10^19 m^-3 has been achieved. Being a medium sized tokamak, runaway electron (RE) generation, transport and mitigation experiments have always been one of the prime focus of ADITYA-U. MHD activities and density enhancement with H2 gas puffing studied. The Phase-I operation was completed in March 2017. The Phase-II operation preparation in ADITYA-U includes calibration of magnetic diagnostics followed by commissioning of major diagnostics and installation of baking system. After repeated cycles of baking the vacuum vessel up to ~ 130°C, the Phase-II operations resumed from February 2018 and are continuing to achieve plasma parameters close to the design parameters of circular limiter plasmas using real time plasma position control. Hydrogen gas breakdown was observed in more than ~2000 discharge including Phase-I and Phase-II operation without a single failure. Several experiments, including the primary RE control with lower E/P operation and secondary RE control with fuelling of Supersonic Molecular Beam Injection as well as sonic H2 gas puffing during current flat-top and Neon gas puffing for better plasma confinement are undergoing. The dismantling of ADITYA and reassembling of ADITYA-U along with experimental results of Phase-I and Phase-II operations from ADITYA-U will be discussed.

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“…The gas puff parameters such as pulse width timing, voltage level, time for gas puff to start, number of pulses and the time gap between pulses can be adjusted as per the requirements of the experiment. Plasma position is controlled by a spectroscopic reference signal and a real time feedback control system [22]. This system simultaneously monitors the H α emissions using two vertical LoS at the same radial locations on the low and high field sides of the plasma from the bottom port of the machine.…”

Section: Methodsmentioning

confidence: 99%

Observation of poloidal asymmetry in measured neutral temperatures in the Aditya-U tokamak plasma

Yadava¹,

Ghosh

Chowdhuri

et al. 2019

Nucl. Fusion

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The neutral particle temperature in the edge region of the Aditya-U tokamak has been measured by recording the hydrogen Balmer alpha emission spectra at 656.28 nm from different lines of sight in both the high and low field sides. The spatial profile of the Hα emission has been recorded using a 1 m multi-track spectrometer. The neutral temperature is estimated from the Doppler broadening of the measured Hα spectrum by appropriately removing the contribution from the Zeeman splitting of the spectral lines. A computer simulation code was developed to estimate the neutral temperature by including the broadening mechanisms such as Doppler broadening and the Zeeman effect to simulate the Hα emission spectrum along with the proper convolution of the instrumental width of the diagnostic system. It has been observed that the high field side neutral temperature (~4–6 eV) during plasma flat top is almost twice that of the low field side (~2–3 eV) suggesting poloidal asymmetry in the neutral temperature.

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Real-time feedback control system for ADITYA-U horizontal plasma position stabilisation

Cited by 7 publications

References 20 publications

Overview of recent experimental results from the ADITYA-U tokamak

Overview of recent experimental results from the ADITYA-U tokamak

Overview of operation and experiments in the ADITYA-U tokamak

Observation of poloidal asymmetry in measured neutral temperatures in the Aditya-U tokamak plasma

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