K.A. Jadeja
A5082482549- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Atomic and Subatomic Physics Research
- Plasma Diagnostics and Applications
- Nuclear reactor physics and engineering
- Nuclear Physics and Applications
- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Radiation Detection and Scintillator Technologies
- Nuclear Materials and Properties
- Solar and Space Plasma Dynamics
- Advanced Biosensing Techniques and Applications
- Magnetic Field Sensors Techniques
- Advanced Data Processing Techniques
- Advanced MEMS and NEMS Technologies
- Quantum and Classical Electrodynamics
- Advanced Electrical Measurement Techniques
- Oil and Gas Production Techniques
- Laser Design and Applications
- Mechanical and Optical Resonators
- Electrostatic Discharge in Electronics
Institute for Plasma Research
2016-2025
Saurashtra University
2019-2024
Pandit Deendayal Petroleum University
2021
Homi Bhabha National Institute
2021
Weatherford College
2014
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...
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...
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. The is driven by servo motor, which controlled PXI-commanded controller. It can be operated remotely precise control over speed, acceleration, and distance traveled head on shot-to-shot basis. HRDS-driven linear array Langmuir measurements floating potential, electron density, temperature revealed that gas puff...
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...
Microwave interferometry has been used extensively for plasma diagnostics in tokamak real-time electron density measurements. Real-time measurement is an indispensable part of advanced tokamaks, as it can be feedback to control the operation. In this article, we report development phase extraction method a heterodyne interferometer estimation using field-programmable gate array (FPGA). FPGA provides parallel processing, minimum delay, more efficient processing architecture, and jitter-free...
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...
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...
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....
Lithiumization of the vacuum vessel wall Aditya tokamak using a lithium rod exposed to glow discharge cleaning plasma has been done understand its effect on performance. After Li-coating, an increment ∼100 eV in electron temperature observed most discharges compared without Li coating, and shot reproducibility is considerably improved. Detailed studies impurity behaviour hydrogen recycling are made coated by observing spectral lines hydrogen, carbon, oxygen visible region optical fiber,...
An impurity ion toroidal rotation profile has been observed in the ohmic discharges of Aditya-U tokamak from Doppler-shifted passive charge exchange line emission C5+ at 529 nm. The monitored using a space-resolved visible spectroscopy diagnostic consisting 1 m multi-track spectrometer coupled with device (CCD) detector. In typical central chord-averaged electron density ≲2.5 × 1019 m−3, maximum velocity plasma core is found to be −20 km s−1 counter-current direction. Reversal for high ~5...
A 140 GHz phase-locked heterodyne interferometer system has been designed, developed and installed at Aditya Tokamak for real time density measurement. The uses a novel approach of zero-cross detection using in-phase quadrature (IQ) signals with single balanced mixer. transmitter receiver systems are phase locked by 100 MHz crystal oscillator the output mixed in mixer which produces highly stabilized intermediate frequency (IF) 2.0 GHz. This signal is further amplified low noise amplifier...
In the ADITYA Upgrade tokamak, glow discharge wall conditioning (GDC) is performed regularly during high-temperature plasma operation cycle using hydrogen (H) and helium (He) gases. H GDC carried out after long durations (few hours) of operations on every day in automatic mode to control oxygen (O) carbon (C) containing impurities. This leads high retention gas graphite limiter plates stainless steel (SS) vessel walls. Subsequently, outgassing requires a prolonged pumping time recycling...
Two dimensional interchange turbulence has been used to describe neon gas interaction with tokamak plasma, and is able include anomalous transport effects self-consistently in the edge scrape-off layer (SOL) regions. Model equations related plasma coupled have solved numerically using BOUT++ framework code. different fluid models of investigated, this context a few results Aditya are presented. Numerical indicate that ionization radiative cooling processes modify turbulence. The existence...
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 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...
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...