A5110171544- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Fusion materials and technologies
- Superconducting Materials and Applications
- Thermodynamic and Structural Properties of Metals and Alloys
- Laser-induced spectroscopy and plasma
- Advanced Chemical Physics Studies
- Surface and Thin Film Phenomena
- Dust and Plasma Wave Phenomena
- Atomic and Subatomic Physics Research
- Magneto-Optical Properties and Applications
- Electron and X-Ray Spectroscopy Techniques
- Health Systems, Economic Evaluations, Quality of Life
- Meta-analysis and systematic reviews
- Nuclear reactor physics and engineering
- Sustainable Development and Environmental Policy
- Microwave and Dielectric Measurement Techniques
- Community Development and Social Impact
- Scientific Measurement and Uncertainty Evaluation
- Real-time simulation and control systems
- Transport Systems and Technology
- Vehicle Dynamics and Control Systems
West Bengal University of Health Sciences
2025
Government of West Bengal
2025
Saha Institute of Nuclear Physics
1999-2024
Institute for Plasma Research
2020-2021
Homi Bhabha National Institute
2020
Institute of Physics, Bhubaneshwar
1980-1985
In the Helicon eXperimental (HeX) device, geometric aperture is fixed, but position of magnetic can be varied. Working with Argon gas in pressure range 1 − 10 × 4 mbar, an annular plasma (density ∼ 16 m 3) formed downstream, always front aperture. This occurs irrespective relative or presence a radial electric field. contrary to earlier proposition made by others that field necessary produce hollow profile. Instead, ionization neutrals radially outer region tail electrons, rotating fast due...
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...
As the world approaches achieving Sustainable Development Goals (SDGs) and moving towards a low-carbon economy, sustainable finance is acknowledged as key ingredient. With focus on how may be used to redirect capital flows environmental, social, governance (ESG) goals, this study examines theoretical foundations of finance. The primary challenge with using achieve SDGs overcoming barriers like inadequate regulations, inconsistent ESG indicators, poor data transparency. These issues hampers...
Abstract Background “Pain, Knee, Motion, Amelioration” in the Extremities chapter of Kent's repertory with 20 enlisted medicines is one most frequently encountered rubrics homeopathy but has not been evaluated systematically. Bayesian statistics resulting likelihood ratio (LR) could offer a better evaluation as well eligibility other medicines. Methods An analytical, epidemiological, longitudinal outcome study was conducted different outpatient departments D.N. De Homoeopathic Medical...
Disruptions, induced in Aditya tokamak by hydrogen gas puffing, are successfully mitigated through stabilization of magnetohydrodynamic (MHD) modes applying a bias voltage to an electrode placed inside the last-closed flux surface prior injection. Above threshold sheared Er × Bφ rotation plasma generated edge biasing leads substantial reduction growth MHD (m/n = 3/1, 2/1), which causes avoidance disruptions prevention mode overlapping and subsequent ergodization magnetic field lines.
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....
Measurements of local plasma parameters in dusty are crucial for understanding the physics issues related to such systems. The Langmuir probe, a small electrode immersed plasma, provides measurements. However, designing probe system environment demands special consideration. First, has be miniaturized enough so that its perturbation on ambient dust structure is minimal. At same time, dimensions must well-defined theory exists interpretation characteristics. associated instrumentation also...
Transition from single to multiple axial potential structure (MAPS) formation is reported in expanding helicon plasma. This transition created by forming a cusp magnetic field at the downstream after expansion throat. Two distinct drops are separated uniform zone. Non-uniform density distribution exists systems. A cusp-like nourishes both gradients sufficient enough for of these two drops. It also shown that and structures observed only when geometric expansions closely coincide with each...
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...
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 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...
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...
In a quasineutral plasma, electrons undergo collective oscillations, known as plasma when perturbed locally. The oscillations propagate due to finite temperature effects. However, the wave can lose phase coherence between constituting oscillators in an inhomogeneous (phase mixing) because of dependence oscillation frequency on density. longitudinal electric field associated with may be used accelerate high energies by exciting large amplitude wave. However maximum is reached that sustain,...
Attempts to operate a tokamak at qa < 2 are normally found terminate with major disruption. In the SINP tokamak, however, it has been possible 1 comparative ease. this letter, an attempt is made quantify rate of current rise required set up discharges having and by comparing risetime resistive diffusion timescale. It observed that less than particular value can be obtained if time taken cross previous barrier time. When barrier, becomes extremely difficult next lower
Breakdown phenomena in the SINP tokamak are studied experimentally for different values of filling pressure (p), toroidal electric field (E), magnetic and vertical by using a hot filament preionization system. had been achieved wide range E/p, starting from 100 up to 4000 V.cm-1.torr-1. In present experiment it has observed first time that there exists an optimum value on either side which breakdown increases. The experimental results have explained terms model Hutchinson Strachan (1974),...
Impurity ion temperatures and their rate of rise were anomalously high ( ${T}_{i}>{T}_{e}$) in the SINP tokamak having a current density low toroidal magnetic field ${q}_{a}\ensuremath{\approx}1.5$). The dynamo effect, which is believed to explain anomaly such discharges reversed-field pinch or ultralow ${q}_{a}$ other tokamaks cannot account for our heating results. Large fluctuations ${n}_{e}$, potential frequency...
Abstract A negative frequency shift is observed to the classical plasma ω pl in metals long‐wavelength limit ( k = 0) by analysing zeroes of dielectric function a degenerate many‐electron system evaluated beyond random phase approximation (RPA). This achieved accounting for non‐RPA contributions arising from virtual plasmon effects effective interaction lines associated with local field correction diagrams. Redefining critical wave vector c experimentally reproduced at 0 Li, Al, and Na...
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,...
Two interesting features of runaway behaviour are observed in the startup phase very low qa (VLQ) (1 < 2) discharges SINP tokamak. As was reduced by lowering toroidal field values, hard X (HX) ray intensity (which indicates presence electrons) fell considerably. The time at which peak HX occurs also shifts ahead time, indicating premature dumping electrons. This seems to aid development rest discharge as exhibited diamagnetic loop signal.
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 spectral analysis of floating potential fluctuations measured in the edge plasma region (0.87 &lt; r/a 1.0) Saha Institute for Nuclear Physics tokamak (SINP-tokamak) using Langmuir probes reveals existence a highly coherent mode with frequency range 15–21 kHz. Long correlations poloidal and toroidal directions are observed over wide discharges having different values safety factor, from very low qedge (&lt;2) to high (&gt;3). These modes simultaneously density radial electric...
A set of 36 magnet coils is used to produce a continuous, uniform magnetic field about 0.35 Tesla inside the vacuum chamber MaPLE Device, linear laboratory plasma device (3 m long and 0.30 in diameter) built for studying basic magnetized physics phenomena. To protect water cooled-coils from serious damage due overheating temperatures all are monitored electronically using low cost temperature sensor IC chips, technique first being similar system. Utilizing Parallel Port Personal Computer...
In the Saha Institute of Nuclear Physics Tokamak (SINP-TOKAMAK), simultaneous measurement signals from some diagnostics, like, electrostatic probes, etc., is not possible because pickup noises due to formation ground and other loops affect them quite severely. To avoid these also isolate diagnostics ground, we developed a new type optical isolator using very low cost chip (MC2TE made by Motorola) in novel configuration. We continuously kept light emitting diode on used feedback arrangement...