Runaway electron mitigation with supersonic molecular beam injection (SMBI) in ADITYA-U tokamak

Banerjee, Santanu; Singh, Kaushlender; Raj, Harshita; Arambhadiya, B.; George, Siju; Jadeja, K. A.; Singh, Amit K.; Edappala, Praveenlal; Bisai, N.; Ghosh, Joydeep; Manchanda, R.; Chowdhuri, M. B.; Tanna, R.L.; Raval, Jayesh; Nagora, Umesh; Paravastu, Yuvakiran; Raval, Dilip C; Mishra, K.; Chandra, D.; Sen, Abhijit

doi:10.1088/1741-4326/abc318

Cited by 6 publications

(5 citation statements)

References 40 publications

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“…However, there are some discharges where the REs are affected less and HXR bursts are not reduced appreciably after the SMBI pulse. There is a strong correlation observed between mode rotation frequency of tearing modes and RE reduction [30]. With the sharp reduction in mode rotation frequency, the HXR burst is substantially reduced.…”

Section: Res Mitigation By Smbi In Aditya-umentioning

confidence: 87%

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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Section: Res Mitigation By Smbi In Aditya-umentioning

confidence: 87%

Overview of operation and experiments in the ADITYA-U tokamak

et al. 2019

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“…The radial electric field has been estimated from the measurement of poloidal and toroidal rotation velocities over the plasma radius [19]. Furthermore, experiments on fuelling with supersonic molecular beam injection for RE mitigation have also been carried out in ADITYA-U [20].…”

Section: Introductionmentioning

confidence: 99%

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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“…Studies of RE beam stability, control and mitigation were also reported from the COMPASS [102] and ADITYA-U [103] devices utilizing RE beams in ohmic flat-top plasmas. Focussing on stability and control of the RE beam, the COMPASS team reported that while vertical position control did not present major challenges, even at high values of elongation, maintaining radial position was more problematic.…”

Section: Disruption Prevention Avoidance and Mitigationmentioning

confidence: 99%

27th IAEA Fusion Energy Conference: summary of sessions EX/C, EX/S and PPC

Campbell¹

2020

Nucl. Fusion

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Developments presented at the 27th IAEA Fusion Energy Conference in several areas of experimental magnetic confinement fusion research relating to confinement physics, plasma stability, plasma performance and control are reviewed. First results were reported from significant new stellarator and tokamak facilities and wide-ranging studies of issues such as disruption mitigation, control of edge localized modes (ELMs), the influence of hydrogenic isotope on heat and particle transport, optimization of ELMy H-modes and advanced H-modes and the application of advanced control techniques have been performed in support of the preparations for ITER operation.

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Runaway electron mitigation with supersonic molecular beam injection (SMBI) in ADITYA-U tokamak

Cited by 6 publications

References 40 publications

Overview of operation and experiments in the ADITYA-U tokamak

Overview of operation and experiments in the ADITYA-U tokamak

Overview of recent experimental results from the ADITYA-U tokamak

27th IAEA Fusion Energy Conference: summary of sessions EX/C, EX/S and PPC

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