R. Manchanda
A5083093744- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Superconducting Materials and Applications
- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Atomic and Subatomic Physics Research
- Nuclear reactor physics and engineering
- Solar and Space Plasma Dynamics
- High-pressure geophysics and materials
- Nuclear Physics and Applications
- Anomaly Detection Techniques and Applications
- Gyrotron and Vacuum Electronics Research
- Laser Design and Applications
- Vacuum and Plasma Arcs
- Laser Material Processing Techniques
- Diverse Topics in Contemporary Research
- Topic Modeling
- Impact of AI and Big Data on Business and Society
- Network Security and Intrusion Detection
- Time Series Analysis and Forecasting
- Nuclear Engineering Thermal-Hydraulics
Institute for Plasma Research
2014-2024
Poornima University
2024
Chandigarh University
2024
Pandit Deendayal Petroleum University
2021
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...
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....
Intense visible lines from Be-like oxygen impurity are routinely observed in the Aditya tokamak. The spatial profile of brightness a spectral line (2p3p 3D3–2p3d 3F4) at 650.024 nm is used to investigate transport typical discharges A 1.0 m multi-track spectrometer (Czerny–Turner) capable simultaneous measurements eight sight obtain radial O4+ emission. emissivity emission obtained using an Abel-like matrix inversion. coefficients determined by reproducing experimentally measured profiles...
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...
Major disruptions in tokamak pose a serious threat to the vessel and its surrounding pieces of equipment. The ability systems detect any behavior that can lead disruption help alerting system beforehand prevent harmful effects. Many machine learning techniques have already been use at large tokamaks like JET ASDEX, but are not suitable for ADITYA, which is comparatively small. Through this work, we discuss new real-time approach predict time ADITYA validate results on an experimental...
A diagnostic system based on a multi-fiber input high resolution spectrograph has been set up the Aditya tokamak (Bhatt et al 1989 Ind. J. Pure Appl. Phys. 27 710) for utilizing passive light emission to measure different kinds of plasma flow and identify location emissions hydrogen impurities along with their temperatures. Eight simultaneous vertically collimated lines-of-sight from top port view poloidal cross-section plasma. This arrangement simplifies analysis spectra in terms making...
The feasibility of inferring the plasma parameters a Penning discharge in helium, from experimentally observed intensities number spectral lines visible wavelength region, is explored. collisional-radiative model ADAS (atomic data analysis structure) code and database has been used for this analysis. electron density, temperature, ground-state atom ion densities also 2 3S metastable state density are thus estimated. results encouraging. derived then to obtain few vacuum ultraviolet (VUV)...
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...
Negative spikes followed by positive ones in the loop voltage signal during discharge are observed Aditya Tokamak [S. B. Bhatt et al., Indian J. Pure Appl. Phys. 27, 710 (1989)]. These always accompanied hard x-ray bursts caused sudden loss of runaway electrons. The growth m=3 mode seemed responsible for losses localized beams electrons (Eγ∼1–5 MeV) from plasma region around q=3 magnetic surface. movement these their extraction inside induces both and negative electric fields at those...
Neutral particle behavior in Aditya tokamak, which has a circular poloidal ring limiter at one particular toroidal location, been investigated using DEGAS2 code. The code is based on the calculation Monte Carlo algorithms and mainly used tokamaks with divertor configuration. This successfully implemented tokamak penetration of neutral hydrogen atom studied various atomic molecular contributions it found that maximum contribution comes from dissociation processes. For same, Hα spectrum also...
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...
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...
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...
A high-resolution spectroscopic diagnostic for the measurement of spatial profiles impurity ion toroidal rotation velocities on ADITYA-U tokamak has been upgraded to cover complete plasma minor radius. Earlier, coverage diagnostics toward edge was restricted due placement collection optics tangential port outside vacuum vessel. The full radius, from 0 24 cm, achieved using newly designed and developed that have seven lines sight view mounted inside a customized re-entrant which is installed...
In this paper, the development of large volume double ring Penning plasma discharge source for efficient light emissions is reported. The developed consists two cylindrical end cathodes stainless steel having radius 6 cm and a gap 5.5 between them, which are fitted in top bottom flanges vacuum chamber. Two anode rings with thickness 0.4 inner diameters 6.45 separation 2 kept at centre. Neodymium (Nd(2)Fe(14)B) permanent magnets physically inserted behind producing nearly uniform magnetic...
In SST-1, 42GHz ECRH system has been commissioned to carry out breakdown and heating experiments at 0.75T 1.5T operating toroidal magnetic fields. The consists of high power microwave source Gyrotron capable deliver 500kW for 500ms duration, approximately 20 meter long transmission line a mirror based launcher. in fundamental O-mode & second harmonic X-mode is launched from low field side (radial port) the tokamak. At operation, 300 kW ECH successful assisted achieved loop_voltage ~ 3V....
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...