A5079448639- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Ionosphere and magnetosphere dynamics
- Atomic and Molecular Physics
- Particle accelerators and beam dynamics
- Fusion materials and technologies
- Laser-induced spectroscopy and plasma
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Solar and Space Plasma Dynamics
- Laser Design and Applications
- Thermography and Photoacoustic Techniques
- Diamond and Carbon-based Materials Research
- Muon and positron interactions and applications
- Metallurgy and Material Forming
- Welding Techniques and Residual Stresses
Institute for Plasma Research
2009-2025
Homi Bhabha National Institute
2023-2024
Experimental observations of the intrinsic excitation and non-linear interactions drift wave (DW) Kelvin–Helmholtz (KH) instabilities in a linear magnetized plasma column are presented. The experiments carried out inverse mirror experimental device (IMPED)—a cylindrical, magnetized, machine designed to study low-frequency waves plasma. A novel feature IMPED is ability control profiles, such as density n(r), electron temperature Te(r), potential Vp(r) by varying ratio Rm magnetic field main...
A long confinement time of electron plasma, approaching magnetic pumping transport limit, has been observed in SMARTEX-C (a small aspect ratio partial torus with Ro/a∼1.59). Investigations the growth rate reveal that they are governed by instabilities like resistive wall destabilization, ion driven instabilities, and electron-neutral collisions. Successful plasmas exceeding >1×105 poloidal E→×B→ rotations lasting for nearly 2.1±0.1 s is achieved suppressing these instabilities. The...
SMall Aspect Ratio Toroidal Experiments in a C-shaped trap (SMARTEX-C) attempts to confine electrons toroidal using static electric and magnetic field. Confinement of these is largely limited by charge losses due the presence background neutrals short pulsed Ions formed electron impact ionization lead instabilities that are ultimately observed limit confinement. Lowering amount therefore paramount importance. In SMARTEX-C, prior injection, pumped down base pressures order 2 ± 1 × 10−8 mbar....
Experiments with trapped electron plasmas in a SMall Aspect Ratio Toroidal device (SMARTEX-C) have demonstrated flute-like mode represented by oscillations on capacitive (wall) probes. Although analogous to diocotron observed linear traps, the evolution toroids can interesting consequences due presence of in-homogeneous magnetic field. In SMARTEX-C, probe signals are undergo transition from small, near-sinusoidal large amplitude, non-linear “double-peaked” oscillations. To interpret wall...
A suitable charge-collector has been designed and developed to estimate charge-content of electron plasmas in a Small Aspect Ratio Toroidal Experiment C-shaped trap (SMARTEX-C). The electrons are periodically injected held the with aid electrostatic end-fields toroidal magnetic field. After preset “hold” time, trapped charges dumped onto grounded collector (by gating it). As flow along field lines collector, integrated current gives plasma at instant dump. In designing such charge several...
Confinement time of electron plasmas trapped using a purely toroidal magnetic field has been found to exceed [Formula: see text] in small aspect ratio ([Formula: text], and are device major minor radius, respectively), partial torus. It improves upon the previously reported confinement by nearly two orders magnitude. Lifetime is estimated from frequency scaling linear diocotron mode launched sections wall, that also used for diagnostics. as neutral pressures reduced presence steady state 200...
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...
The spectral analysis of floating potential fluctuations measured in the edge plasma region (0.87 < 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 (<2) to high (>3). These modes simultaneously density radial electric...
The main causes of the energy losses in a tokamak are radiation, ion-neutral charge exchange and plasma transport processes. Infrared thermography is carried out on poloidal limiter ADITYA with an infrared camera. Analysis these thermographic images can enhance our understanding plasma-limiter interaction. Surface temperature measurement give us heat flux falling its variation time. This over time be useful calculation power balance compared total input power. measured toroidal is, general,...
Abstract A scheme to construct a Paul Trap trap positrons and create ‘Pure Positron Plasma’ has been presented. Positrons from sealed source ( 22 Na) are moderated down ∼ 2.5 eV with an energy spread of ≤1 pre‐treated 1 μm Tungsten moderator held at room temperature moderation efficiency 6 × 10 –4 – 2 –3 . The is further adjusted about 42 by biasing the before their entry in trap. entering cooled buffer gas (inelastic collisions N or CO ) low pressure, hence fall pseudo‐potential well. This...
Microcontroller based trigger control circuit for fast pulsing of electrode potentials on wide range time scales has been designed, installed, and tested electron plasma experiments which are carried out in partial toroidal trap SMall Aspect Ratio Toroidal Electron EXperiment C – shaped geometry (SMARTEX C), a device to create confine non-neutral (electron plasma). The sequence operation is inject-hold-dump electrodes need be pulsed with applied voltages at high switching speed few...
Confinement time of electron plasmas trapped using a purely toroidal magnetic field has been extended to $\sim 100$ s in small aspect ratio ($R_{o}/{a} \sim {1.59}$, $R_o$ and $a$ are device major minor radius, respectively), partial torus. It surpasses the previous record by nearly two orders magnitude. Lifetime is estimated from frequency scaling linear diocotron mode launched sections wall, that also used for diagnostics. improves enormously with reduction neutral pressure presence steady...