Suman Dolui
A5005528925- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Fusion materials and technologies
- Laser-Plasma Interactions and Diagnostics
- Superconducting Materials and Applications
- Nuclear reactor physics and engineering
- Atomic and Subatomic Physics Research
- Plasma Diagnostics and Applications
- Radiation Detection and Scintillator Technologies
- Nuclear Materials and Properties
- Magnetic Field Sensors Techniques
- Nuclear Engineering Thermal-Hydraulics
- Solar and Space Plasma Dynamics
Institute for Plasma Research
2020-2024
Homi Bhabha National Institute
2020-2024
Experiments on ADITYA-U tokamak show a marked enhancement in the sawtooth period by application of short gas puffs fuel that cause modification radial density profile. A consequent suppression trapped electron modes (TEMs) then leads to an increase core temperature. This slows down heat propagation following crash, causing delay achieving critical temperature gradient inside q = 1 surface required for next crash happen. The overall scenario has strong similarities with behavior under...
This article reports the development of a versatile high-speed reciprocating drive system (HRDS) with interchangeable probe heads to characterize edge plasma region ADITYA-U tokamak. consisting Langmuir and magnetic heads, is designed, fabricated, installed, operated for studying extent fuel/impurity gas propagation its influence on dynamics in far-edge inside last closed flux surface (LCFS). The HRDS driven by highly accurate, easy-to-control, dynamic, brushless, permanently excited...
Abstract Since the 2018 IAEA-FEC conference, in addition to expanding parameter horizons of ADITYA-U machine, emphasis has been given 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 Ar injection, modulation magneto–hydrodynamic modes, edge turbulence periodic gas puffs electrode biasing (E-B). Plasma parameters close design circular plasmas...
Abstract A first-of-its-kind, inductively driven micro-particle (Pellet) accelerator and injector have been developed operated successfully in ADITYA-U circular plasma operations, which may ably address the critical need for a suitable disruption control mechanism ITER future tokamak. The device combines principles of electromagnetic induction, pulse power technology, impact, fracture dynamics. It is designed to operate variety environments, including atmospheric pressure ultra-high vacuum....
Abstract Effective control of impurities and precise regulation the fueling gas are supreme prerequisites for optimal operation in any fusion device. Conventional wall-conditioning methods fall short achieving wall conditioning. methods, such as vessel baking H 2 /(D )-fueled glow discharge cleaning (GDC), generally required to remove wall-absorbed bulk after venting. The excess amount hydrogen, injected during GDC, can be reduced by helium (He)-fueled GDC. However, He removal from is more...
Short bursts (1 -2 ms) of gas, injecting ~ 10 17 -10 18 molecules hydrogen as well deuterium, lead to observations phenomena cold pulse propagation in plasmas the ADITYA-U tokamak.After every injection gas-pulse, a sharp increase chord-averaged density followed by an core temperature has been observed.Simultaneously edge and decreases, suggesting due gas-pulse application.It observed that subsequent depend on both value plasma at instant gasinjection amount gas injected up threshold...
Abstract In fusion devices, various techniques are employed for coating the plasma facing components (PFCs) including vessel wall with low-Z material like lithium, boron, and silicon in order to enhance parameters control. ADITYA-Upgrade tokamak, different of lithium conditioning developed implemented obtain uniform sustainable Li on PFCs wall. this paper, two used generate from source reported. one technique, a heated (fixed temperature ∼120 °C) Li-rod is placed inside hydrogen glow...
We present experimental results of the trace argon impurity puffing in ohmic plasmas Aditya-U tokamak performed to study transport behaviour. Argon line emissions visible and Vacuum Ultra Violet (VUV) spectral ranges arising from plasma edge core respectively are measured simultaneously. During experiments, space resolved brightness profile Ar1+ at 472.69 nm (3p44s 2P3/2-3p44p 2D3/2), 473.59 4P5/2-3p44p 4P3/2), 476.49 2P1/2-3p44p 2P3/2), 480.60 4P5/2) recorded using a high resolution...
The effect of a periodic train short gas-puff pulses on the rotation frequency and amplitude drift-tearing modes has been studied in ADITYA/ADITYA-U tokamak.The gas puffs, injecting approximately ~10 17 -10 18 molecules fuel (hydrogen) at one toroidal location, are found to concomitantly decrease mode during period injection then recover back its initial values when pulse is over.This leads modulation that correlated with periodicity injection.The underlying mechanism for this change...
Runaway Electrons (REs) generated during plasma disruptions in fusion grade tokamaks have the potential to severely damage plasma-facing components. Designing optimal discharge scenarios for RE suppression future experiments requires interpretative modeling of current experiments. Multiple been carried out on ADITYA-U tokamak design avoidance and suppression. In this article, we numerically studied two representative pairs discharges. first pair discharges, density was increased by gas puffs...
Plasma equilibrium in ADITYA/ADITYA-U is provided by two pairs of vertical field coils (BV1 & BV2) placed outside the vessel. A peak loop voltage ∼20 V required for successful breakdown and start-up ADITYA, which leads to a higher IP ramp-rate ∼6 - 8 MA/Sec during first ∼7 ms discharge. To hold plasma column equilibrium, should also be ramped-up at same rate. Series connections (BV) do not provide ramp rate due high L/R time-constant 12 pulse converter firing. Therefore, additional...
Controlling and mitigating plasma disruptions are a matter of serious concern for tokamak operation since they can cause damage to the machine. Dedicated experiments on disruption mitigation have been carried out in ADITYA (R = 75 cm, 25 cm), an Ohmically heated circular limiter tokamak. A rapid growth magneto hydrodynamic (MHD) modes is found be major Stimulated induced by hydrogen gas puffing successfully mitigated through stabilization these MHD applying biased-electrode placed inside...
The influence of background plasma poloidal rotation on the frequency m/n = 2/1 drift tearing mode (DTM) has been studied in ADITYA-U tokamak. velocity ion diamagnetic direction is increased or decreased by inducing an outward inward radial electric field, respectively, through a biased-electrode placed edge region plasma. preexisting mode, rotating electron direction, concomitantly with application bias depending its polarity. positive-bias increases ion-diamagnetic from pre-bias value,...
Abstract The ADITYA upgrade (ADITYA-U), a medium-sized <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>(</mml:mo> <mml:msub> <mml:mi>R</mml:mi> <mml:mn>0</mml:mn> </mml:msub> </mml:mrow> <mml:mo>=</mml:mo> <mml:mn>75</mml:mn> <mml:mtext> cm</mml:mtext> <mml:mo>,</mml:mo> <mml:mstyle scriptlevel="0"/> <mml:mi>a</mml:mi> <mml:mn>25</mml:mn> <mml:mo>)</mml:mo> </mml:math> conventional tokamak facility in India, has been consistently producing...
Abstract Intrinsic toroidal rotation velocity ( V φ ) has been measured from the Doppler shift of C 5+ carbon spectral lines (at 529.05 nm) in edge region ADITYA-U tokamak without any auxiliary torque input an ohmically heated pure hydrogen (H 2 plasma as well H plasmas seeded with medium-Z (neon and argon) impurities . The is observed to reverse its direction counter-current co-current increase current beyond I p ∼ 145–150 kA. Furthermore, a systematic decrease density, which tends almost...
A diamagnetic diagnostic system is designed, prepared and installed at Aditya Upgrade Tokamak. Also, the raw data acquired in a specified acquisition with suitable front-end electronics. The entire consists of separate loops first calibrated presence all coils, which conduct electricity during plasma discharge. Then, change toroidal magnetic field due to measured using system, hence, several parameters including poloidal beta, stored energy, etc. are estimated. measurements were then...
In this paper, we report the excitation of coherent density and potential fluctuations induced by magnetohydrodynamic (MHD) activity in edge plasma region ADITYA-U tokamak. When amplitude MHD mode, mainly m/n = 2/1, increases beyond a threshold value, |B̃θ|/Bθ ∼ 0.3%–0.4%, oscillations are observed having same frequency as that mode. The mode numbers these obtained Langmuir probes placed at different radial, poloidal, toroidal locations region. Detailed analyses probe measurements reveal...
Abstract We present experimental results of the trace argon impurity puffing in Ohmic plasmas Aditya-U tokamak performed to study transport behaviour. Argon line emissions visible and Vacuum Ultra Violet (VUV) spectral ranges arising from plasma edge core respectively are measured simultaneously. During experiments, space resolved brightness profile Ar 1+ at 472.68 nm (3p 4 4s 2 P 1.5 - 3 p 4p D ), 473.59 (3p44s 4P2.5 3p44p 4P1.5), 476.48 2P 0.5 3p 480.60 4P 2.5 ) recorded using a high...