V. Kiptily
A5068023703- Magnetic confinement fusion research
- Fusion materials and technologies
- Nuclear Physics and Applications
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Radiation Detection and Scintillator Technologies
- Nuclear physics research studies
- Solar and Space Plasma Dynamics
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Plasma Diagnostics and Applications
- Atomic and Molecular Physics
- Medical Imaging Techniques and Applications
- Radiation Effects in Electronics
- Parallel Computing and Optimization Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Laser-induced spectroscopy and plasma
- Particle physics theoretical and experimental studies
- Meteorological Phenomena and Simulations
- Advanced Data Storage Technologies
- High-Energy Particle Collisions Research
- Advanced X-ray and CT Imaging
Culham Centre for Fusion Energy
2015-2024
Culham Science Centre
2015-2024
United Kingdom Atomic Energy Authority
2003-2024
Royal Military Academy
2020
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2006-2016
École nationale des ponts et chaussées
2012
KTH Royal Institute of Technology
2010
Princeton Plasma Physics Laboratory
2004-2010
National Institute for Research and Development of Isotopic and Molecular Technologies
2009
Forschungszentrum Jülich
2009
Type-I edge-localized modes (ELMs) have been mitigated at the JET tokamak using a static external $n=1$ perturbation field generated by four error correction coils located far from plasma. During application of ELM frequency increased factor 4 and amplitude ${\mathrm{D}}_{\ensuremath{\alpha}}$ signal decreased. The energy loss per normalized to total stored energy, $\ensuremath{\Delta}W/W$, dropped values below 2%. Transport analyses shows no or only moderate (up 20%) degradation confinement...
Abstract In JET deuterium-tritium (D-T) plasmas, the fusion power is produced through thermonuclear reactions and between thermal ions fast particles generated by neutral beam injection (NBI) heating or accelerated electromagnetic wave in ion cyclotron range of frequencies (ICRFs). To complement experiments with 50/50 D/T mixtures maximizing reactivity, a scenario dominant non-thermal reactivity has been developed successfully demonstrated during second campaign DTE2, as it was predicted to...
Abstract The JET hybrid scenario has been developed from low plasma current carbon wall discharges to the record-breaking Deuterium-Tritium plasmas obtained in 2021 with ITER-like Be/W wall. development started pure Deuterium refinement of current, and toroidal magnetic field choices succeeded solving heat load challenges arising 37 MW injected power ITER like environment, keeping radiation edge core controlled, avoiding MHD instabilities reaching high neutron rates. have re-run Tritium...
This paper reports recent progress in the field of γ-ray diagnosis fast ions JET tokamak. The γ-rays, born nuclear reactions between and main plasma impurities and/or fuel ions, are analysed with a new modelling tool (the GAMMOD code) that has been developed for quantitative analysis measured energy spectra. spectra identifies different giving rise to emission assesses effective tail temperatures relative concentrations these ions. assessment is possible, since excitation functions well...
A review of the use gamma ray spectrometry as a diagnostic nuclear reaction rates and product densities in high temperature fusion plasmas is presented. In this we will discuss historic genesis concept, brief overview relevant physics, experimental techniques utilized measurements some analytical required to extract information from basic measurements. Of particular interest ability measure population confined fast alpha particles future burning plasma experiments.
Disruptions are a critical issue for ITER because of the high thermal and magnetic energies that released on short timescales, which results in extreme forces heat loads. The choice material plasma-facing components (PFCs) can have significant impact loads arise during disruption. With ITER-like wall (ILW) JET made beryllium main chamber tungsten divertor, finding is low fraction radiation. This has dropped significantly with ILW from 50–100% total energy being dissipated disruptions CFC...
Disruptions are a major operational concern for next generation tokamaks, including ITER.They may generate excessive heat loads on plasma facing components, large electromagnetic forces in the machine structures and several MA of multi-MeV runaway electrons.A more complete understanding processes methods to suppress them is necessary ensure safe reliable operation future tokamaks.Runaway electrons were studied at JET-ILW showing that their dependencies (accelerating electric field, avalanche...
In October 2014, JET completed a scoping study involving high power scenario development in preparation for DT along with other experiments critical ITER.These have involved intentional and unintentional melt damage both to bulk beryllium main chamber tiles divertor tiles.This paper provides an overview of the findings concern machine protection ITER, illustrating each case resolution images taken by remote handling or after removal from machine.The upper dump plate some been repeatedly...
Remarkable progress has been made in diagnosing energetic particle instabilities on presentday machines and establishing a theoretical framework for describing them.This overview describes the much improved diagnostics of Alfvén modelling tools developed world-wide, discusses interpreting observed phenomena.A multi-machine comparison is presented giving information performance both different plasma conditions outlining expectations ITER based our present knowledge.
Abstract Ion cyclotron resonance frequency (ICRF) heating has been an essential component in the development of high power H-mode scenarios Jet European Torus ITER-like wall (JET-ILW). The ICRF performance was improved by enhancing antenna-plasma coupling with dedicated main chamber gas injection, including preliminary minimization RF-induced plasma-wall interactions, while RF where optimized for core impurity screening terms ion position and minority hydrogen concentration. impact on...
This paper summarizes the physical principles behind novel three-ion scenarios using radio frequency waves in ion cyclotron range of frequencies (ICRF). We discuss how to transform mode conversion electron heating into a new flexible ICRF technique for and fast-ion generation multi-ion species plasmas. The theoretical section provides practical recipes selecting plasma composition realize scenarios, including two equivalent possibilities choice resonant absorbers that have been identified....
Abstract In the paper we present an overview of interpretive modelling a database JET-ILW 2021 D-T discharges using TRANSP code. The main aim is to assess our capability computationally reproducing fusion performance various plasma scenarios different external heating and mixtures, understand driving mechanisms. We find that simulations confirm general power-law relationship between increasing power output, which supported by absolutely calibrated neutron yield measurements. A comparison...
Extensive analysis of disruptions in JET has helped advance the understanding trends disruption-generated runaway electrons. Tomographic reconstruction soft x-ray emission made possible a detailed observation magnetic flux geometry evolution during disruptions. With aid and hard diagnostics electrons have been detected at very beginning A study electron parameters shown that an approximate upper bound for conversion efficiency pre-disruptive plasma currents into runaways is about 60% over...
Plasma disruptions affect plasma-facing and structural components of tokamaks due to electromechanical forces, thermal loads generation high energy runaway electrons (REs). Asymmetries in poloidal halo toroidal plasma current can now be routinely measured four positions 90° apart. Their assessment is used validate the design ITER vessel support system its in-vessel components. The challenge disruption comes from both short duration over which a large has lost potential for asymmetries. focus...
A new high efficiency, resolution, fast γ-ray spectrometer was recently installed at the JET tokamak. The is based on a LaBr3(Ce) scintillator coupled to photomultiplier tube. digital data acquisition system used allow spectrometry with event rates in excess of 1 MHz expected future DT plasmas. However, lower typical present day experiments, digitization can degrade energy resolution system, depending algorithms for extracting pulse height information from digitized pulses. In this paper,...
High resolution γ-ray spectroscopy measurements at MHz counting rates were carried out nuclear accelerators, combining a LaBr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (Ce) detector with dedicated hardware and software solutions based on digitization off-line analysis. Spectra measured up to 4 MHz, little or no degradation of the energy resolution, adopting pile rejection algorithm. The reported results represent step forward...
The spectral broadening of characteristic γ-ray emission peaks from the reaction (12)C((3)He,pγ)(14)N was measured in D((3)He) plasmas JET tokamak with ion cyclotron resonance heating tuned to fundamental harmonic (3)He. Intensities and detailed shapes were successfully reproduced using a physics model combining kinetics reacting ions description nuclear differential cross sections for populating L1-L8 (14)N excitation levels yielding observed emission. results provide paradigm, which...
Observations made in a JET experiment aimed at accelerating deuterons to the MeV range by third harmonic radiofrequency (RF) heating coupled into deuterium beam are reported.Measurements based on set of advanced neutron and gamma-ray spectrometers that, for first time, observe plasma simultaneously along vertical oblique lines sight.Parameters fast ion energy distribution, such as high cut-off deuteron distribution function RF coupling constant, determined from data within uniform analysis...
We demonstrate the measurement of a 2D MeV-range ion velocity distribution function by velocity-space tomography at JET. Deuterium ions were accelerated into third harmonic cyclotron resonance heating. made measurements with three neutron emission spectrometers and high-resolution γ-ray spectrometer detecting γ-rays released in two reactions. The tomographic inversion based on these five spectra is excellent agreement numerical simulations ASCOT–RFOF SPOT–RFOF codes. length measured fast-ion...
The fast-ion distribution from third harmonic ion cyclotron resonance frequency (ICRF) heating on the Joint European Torus is studied using neutron emission spectroscopy with time-of-flight spectrometer TOFOR. energy dependence of fast deuteron function inferred measured spectrum neutrons born in DD fusion reactions, and compared theoretical models for ICRF heating. Good agreements between modelling measurements are seen clear features function, that due to finite Larmor radius resonating...
Gamma-ray spectrometry on ITER can provide information both confined fusion alpha particles for optimization of plasma heating and runaway electrons, which is important safe reactor operations. For the purpose deconvolution gamma-ray spectra recorded in experiments DeGaSum code has been developed. The be applied processing monoenergetic gamma rays, are born nuclear reactions produced by other fast ions, continuous bremsstrahlung generated electrons MeV range structure materials. spectrometer...
Abstract High-resolution γ -ray spectroscopy (GRS) measurements resolve spectral shapes of Doppler-broadened -rays. We calculate weight functions describing velocity-space sensitivities any two-step reaction GRS in magnetized plasmas using the resonant nuclear 9 Be( α , n ) 12 C as an example. The energy-dependent cross sections this suggest that is sensitive to alpha particles above about 1.7 MeV and highly at resonance energies reaction. Here we demonstrate high-resolution are not only...
Dedicated experiments to generate energetic D ions and fusion-born alpha particles were performed at the Joint European Torus (JET) with ITER-like wall (ILW). Using 3-ion radio frequency (RF) heating scenario, deuterium from neutral beam injection (NBI) accelerated in core of mixed plasmas higher energies ion cyclotron resonance (ICRF) waves, turn leading a core-localized source particles. The fast-ion distribution RF-accelerated D-NBI was controlled by varying ICRF NBI power ( 4–6 MW, 3–20...
Abstract We present an overview of results from a series L–H transition experiments undertaken at JET since the installation ITER-like-wall (JET-ILW), with beryllium wall tiles and tungsten divertor. Tritium, helium deuterium plasmas have been investigated. Initial in tritium show ohmic transitions low density power threshold for ( P LH ) is lower than ones densities, while we still lack contrasted data to provide scaling high densities. In there notable shift which minimum <?CDATA...