Jayesh Raval
A5050630664- Magnetic confinement fusion research
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Gyrotron and Vacuum Electronics Research
- Nuclear reactor physics and engineering
- Advanced Wireless Communication Techniques
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Nuclear Materials and Properties
- Advancements in PLL and VCO Technologies
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Radio Frequency Integrated Circuit Design
- Radiation Detection and Scintillator Technologies
Institute for Plasma Research
2011-2024
Indian Space Research Organisation
2012
Several experiments, related to controlled thermonuclear fusion research and highly relevant for large size tokamaks, including ITER, have been carried out in ADITYA, an ohmically heated circular limiter tokamak. Repeatable plasma discharges of a maximum current ~160 kA discharge duration beyond ~250 ms with flattop ~140 obtained the first time ADITYA. The reproducibility has improved considerably lithium wall conditioning, are by precisely controlling position plasma. In these discharges,...
The first Indian tokamak, ADITYA, operated for over two decades with a circular poloidal limiter, has been upgraded to tokamak named ADITYA Upgrade (ADITYA-U) attain shaped-plasma operations an open divertor in single and double-null configurations. Experimental research using ADITYA-U made significant progress since the last FEC 2016. After installation of plasma facing component standard diagnostics ADITYA-U, Phase-I were initiated December 2016 graphite toroidal belt limiter. Ohmically...
A steady state superconducting tokamak (SST-1) has been commissioned after the successful experimental and engineering validations of its critical sub-systems. During 'engineering validation phase' SST-1; cryostat was demonstrated to be leak-tight in all operational scenarios, 80 K thermal shields were uniformly cooled without regions 'thermal runaway hot spots', toroidal field magnets their nominal conditions charged up 1.5 T at major radius. The further assembled SST-1 machine shell a...
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...
This paper summarizes the results of recent dedicated experiments on disruption control and runaway mitigation carried out in ADITYA, which are utmost importance for successful operation large size tokamaks, such as ITER. It is quite a well-known fact that disruptions tokamaks must be avoided. Disruptions, induced by hydrogen gas puffing, successfully avoided two innovative techniques ADITYA using bias electrode placed inside last closed flux surface applying an ion cyclotron resonance pulse...
In order to understand the atomic and molecular processes involved in emission of hydrogen Balmer alpha (H) spectral line from tokamak plasmas, measured radial profile H emissivity ADITYA discharges has been modeled using DEGAS2 neutral particle transport code. The a 1.0 m multi-track spectrometer with PMT array based space-resolved visible spectroscopic diagnostics involving interference filters. density obtained code by reproducing experimentally observed profile. It found that falls...
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...
Iron (Fe) impurity behaviour in ADITYA tokamak plasma has been studied using Fe spectral line emissions the vacuum ultra violet (VUV) wavelength range. A VUV survey spectrometer utilized to record lines at 28.41 nm from Fe14+ , and 33.54 36.08 Fe15+ . It observed that intensities of decrease with an increase electron density. The emission intensity ratio ions two discharges having relatively low high density are modelled transport code. is found data could be same convective velocity...
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...
Study of hard X-ray (HX) spectrum is an important tool to understand the runaway electrons (RE) behavior present in tokamak plasma as these energetic electrons, especially those generated during disruption, represent a major threat devices terms melting and damaging plasma-facing component (PFC) thereby reduced lifetime first wall. A LaBr3(Ce) detector based spectroscopic diagnostic has been set up on Aditya measure HX spectrum. This consists photomultiplier tube multi-channel analyzer along...
The spatial profile of Hα spectrum is regularly measured using a high-resolution multi-track spectrometer in ADITYA tokamak to study the neutral particle behavior. Monte Carlo transport code DEGAS2 used model experimental spectral emissions. Through modeling line Hα, it found that hydrogen, which produced from molecular hydrogen and ion dissociation processes contributes 56% total emission, atoms are charge-exchange process have 30% contribution. Furthermore, experimentally chord integrated...
Silicon drift detector based X-ray spectrometer diagnostic was developed to study the non-thermal electron for Aditya tokamak plasma. The mounted on a radial mid plane port at Aditya. objective of includes estimation temperature ohmically heated Bi-Maxwellian plasma model adopted estimation. Along with that high Z impurity line radiation from ECR pre-ionization experiments also aimed. performance and first experimental results new system are presented.
Abstract The generation and subsequent loss of runaway electrons (REs) during the operation sequence in a tokamak is potent threat to plasma-facing components interface actively cooled parts. Control mitigation REs are prime importance safe machine health fusion device. A supersonic molecular beam injection (SMBI) system has been installed ADITYA-U explore effects high Mach number on ways mitigate REs. In majority discharges which SMBI injected, burst hard x-rays observed accompanying pulse,...
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...
This paper describes the low noise and high gain front-end S-band receiver for portable satellite ground terminal voice, video data communication mainly at time of disaster like earthquake tsunami or remote area where land based networks are not present. design is having very figure, spurious levels. Channel selected RF frequency with use synthesizer. Low Noise, compact size, power consumption, cost satisfaction developed unit.
A system "SYMPLE" is being developed at our laboratory to investigate the interaction of high power microwave and plasma. brief account on development a plasma source that satisfies prerequisites required for SYMPLE discussed.
The non-thermal electrons (NTE) in tokamak plasma have a strong effect over the properties and on facing components. This establishes an importance of NTE to be studied both flux energy space. was for Aditya by monitoring X-ray spectrum using Silicon Drift Detector (SDD) based spectroscopic diagnostic ECR pre-ionization experiments. spectra shows line radiation band top bremsstrahlung. Line is primarily combination multiple characteristics lines existed between 5 keV 7 mostly associated with...
A Pulse Forming Network (PFN) with mutual coupling has been designed, developed and tested for its performance as a pulsed (~100 μs) high voltage (up to 10 KV) source washer gun plasma production in SYMPLE (SYstem Microwave PLasma Experiments). Detailed account of the PFN parameters well test results on discharge is presented here.