A5044829565- Magnetic confinement fusion research
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Gyrotron and Vacuum Electronics Research
- Solar and Space Plasma Dynamics
- Fusion materials and technologies
- Dust and Plasma Wave Phenomena
- Electrohydrodynamics and Fluid Dynamics
- Nuclear reactor physics and engineering
- Radioactive Decay and Measurement Techniques
- Nuclear Physics and Applications
- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Fluid Dynamics and Turbulent Flows
- Second Language Acquisition and Learning
- Quantum, superfluid, helium dynamics
- Chaos control and synchronization
- Spacecraft and Cryogenic Technologies
- Thin-Film Transistor Technologies
- Electromagnetic Compatibility and Measurements
- Atomic and Subatomic Physics Research
- Electrical and Bioimpedance Tomography
- Advanced Frequency and Time Standards
University of Jyväskylä
2024
Institute for Plasma Research
2006-2017
ITER
2009-2013
Fusion for Energy
2011
Forschungszentrum Jülich
1990-1991
Physical Research Laboratory
1979-1987
<title>Abstract</title> While the explosive increase in extreme humid heat stress exposure from 2000’s over South Asian monsoon region is challenging human adaptability leading to productivity and mortality loss, factors responsible remain poorly constrained. Here, we unravel that disruptive regional climate change of decadal-mean maximum Humidex exceeding 45°C be primary cause. Over Northeast India, it results heat-stress during season rising fourfold 80 days or 800 ± 278 hours makes...
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,...
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...
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...
ITER will explore a plasma parameter envelope currently not available in tokamaks. This require set of diagnostics that can follow this envelope. To implement these reliable and robust way requires development current techniques many areas to make them applicable ITER: they need be operable the environment satisfy physics engineering requirements. In some cases, exploitation new required. While much work has been carried out area, significant further remains bring system implementation.
Localized electron temperature and density peaking at different axial locations in the downstream helicon plasma have been observed a linear device with both geometrical magnetic expansion. The discharge is produced an right helical antenna powered by RF source operating 13.56 MHz. Axial wave field measurement shows presence of damped waves standing character folded into it even low densities ( m). measured wavelength just about twice length phase velocity almost speed required for impact...
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...
RF systems in the ion cyclotron resonance frequency (ICRF) range and electron (ECRF) are an advanced stage of commissioning, to carry out pre-ionization, breakdown, heating current drive experiments on steady-state superconducting tokamak SST-1. Initially 1.5 MW continuous wave ICRF system would be used heat SST-1 plasma 1.0 keV during a pulse length 1000 s. For different scenarios at 3.0 T, wide band operating frequencies (20–92 MHz) is required. To meet this requirement two CW rf...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation B. Schunke, D. Bora, R. Hemsworth, A. Tanga; Status of the Negative Ion Based Heating Diagnostic Neutral Beams for ITER. AIP Conf. Proc. 12 March 2009; 1097 (1): 480–490. https://doi.org/10.1063/1.3112548 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation P. U. Lamalle, B. Beaumont, T. Gassmann, F. Kazarian, Arambhadiya, D. Bora, J. Jacquinot, R. Mitteau, C. Schüller, A. Tanga, Baruah, Bhardwaj, Kumar, Mukherjee, N. Singh, Goulding, Rasmussen, Swain, G. Agarici, Sartori, A Borthwick, Davis, Fanthome, Hamlyn‐Harris, Hancock, Kaye, Lockley, M. Nightingale,...
Langmuir probes with variants such as single, double and triple remain the most common method of electron temperature measurement in low-temperature laboratory plasmas. However, proper estimation mainly using probe configuration requires choice compensation factor (W). Determination compensating is not very straightforward it depends heavily on plasma floating potential (Vf), (Te), type gas used for production bias voltage applied to pins, especially cases where there are substantial...
Parametric characterization of multiple double layers is done during high pressure glow discharge in a toroidal vessel small aspect ratio. Although (without magnetic field) known to be independent device geometry, but the boundary conditions are conducive plasma growth and eventually occupy volume partially. At higher anode potential, visibly glowing spots on body spatially extended transform into intensely luminous spherical blob structures attached tip positive electrode. Dynamics observed...
Detailed measurements of density and floating potential in the poloidal cross section a toroidal plasma with an extended source at minor axis are presented first half paper. The second part deals effect k/sub /// on curvature-induced low frequency (< omega i, ion gyro frequency) fluctuations, where is wavenumber parallel to ambient magnetic field. variation introduced help weak vertical field, which helps varying length field lines. We report reduction fluctuation level presence
A 42-GHz electron cyclotron resonance heating (ECRH) system will be used to carry out preionization and start-up experiments on tokamaks SST-1 Aditya. The would give reliable in the tokamak at 1.5-T operating toroidal magnetic field. fundamental O-mode launched from low-field side of tokamak. same Aditya second-harmonic ECRH-assisted breakdown 0.75-T operation. gyrotron capable delivering 500-kW power installed such that it deliver both without dismantling any component. An approximately...
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...
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....
Direct current (DC) driven and turbulence cross-field particle fluxes have been deduced from Langmuir probe measurements during discharges with ion cyclotron resonance heating (ICRH) in the TEXTOR tokamak. Spectral analysis of fluctuations floating potential at spatially separated pins has used to determine velocity associated poloidal rotation boundary plasma. Characteristics spectra density edge ICRH measured compared corresponding standard ohmically heated discharges. It observed that...
Low-frequency turbulence has been studied in a plasma embedded pure toroidal magnetic field. A study of the variation spectral characteristics low-frequency with νin/Ωi carried out two different sets density and potential profiles. The relation between fluctuations indicates that Rayleigh–Taylor instability excites long wavelength region, while driven drift is responsible for short regime νin/Ωi≪1. Spectral observed regions where gradients are parallel to gravity similar case antiparallel...