J. Buchanan
A5101818455- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Computational Physics and Python Applications
- Neutrino Physics Research
- Magnetic confinement fusion research
- Nuclear reactor physics and engineering
- Fusion materials and technologies
- Black Holes and Theoretical Physics
- Astrophysics and Cosmic Phenomena
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Distributed and Parallel Computing Systems
- Radiation Detection and Scintillator Technologies
- advanced mathematical theories
- Medical Imaging Techniques and Applications
- Radiation Effects in Electronics
- Nuclear Physics and Applications
- Muon and positron interactions and applications
- Laser-Plasma Interactions and Diagnostics
Culham Centre for Fusion Energy
2015-2025
Culham Science Centre
2017-2025
Lawrence Livermore National Laboratory
2021-2025
Institute of High Energy Physics
2017-2023
University of Wisconsin–Madison
2017-2023
A. Alikhanyan National Laboratory
2022-2023
University of Oxford
2010-2022
Nuffield Health
2022
Royal Military Academy
2020
United Kingdom Atomic Energy Authority
2019
Abstract The most efficient and promising operational regime for the International Thermonuclear Experimental Reactor tokamak is high-confinement mode. In this regime, however, periodic relaxations of plasma edge can occur. These edge-localized modes pose a threat to integrity fusion device. Here we reveal strong impact energetic ions on spatio-temporal structure in tokamaks using nonlinear hybrid kinetic–magnetohydrodynamic simulations. A resonant interaction between fast at electromagnetic...
TRANSP simulations are being used in the OMFIT workflow manager to enable a machine-independent means of experimental analysis, postdictive validation, and predictive time-dependent on DIII-D, NSTX, JET, C-MOD tokamaks. The procedures for preparing input data from plasma profile diagnostics equilibrium reconstruction, as well processing heating current drive sources assumptions about neutral recycling, vary across machines, but streamlined by using common manager. Settings simulation...
Abstract Model-based plasma scenario development lies at the heart of design and operation future fusion powerplants. Including turbulent transport in integrated models is essential for delivering a successful roadmap towards ITER DEMO-class devices. Given highly iterative nature models, fast machine-learning-based surrogates are fundamental to fulfil pressing need faster simulations opening up pulse design, optimization, flight simulator applications. A significant bottleneck generation...
Abstract Experiments on ASDEX Upgrade (AUG) in 2021 and 2022 have addressed a number of critical issues for ITER EU DEMO. A major objective the AUG programme is to shed light underlying physics confinement, stability, plasma exhaust order allow reliable extrapolation results obtained present day machines these reactor-grade devices. Concerning pedestal physics, mitigation edge localised modes (ELMs) using resonant magnetic perturbations (RMPs) was found be consistent with reduction linear...
The Alfvén instability nonlinearly excited the energetic-particle-driven geodesic acoustic mode on ASDEX-Upgrade tokamak, as demonstrated experimentally. mechanism of excitation and nonlinear evolution is not yet fully understood. In present work, a first-principles simulation using MEGA code investigated properties in both linear growth saturated phases. Here we show that successfully reproduced coexistence these two modes, agreed with experimental results well. Conclusive evidence showed...
We present an open source Python library for simulating overlapping (i.e., blended) images of galaxies and performing self-consistent comparisons detection deblending algorithms based on a suite metrics. The package, named Blending Toolkit (BTK), serves as modular, flexible, easy-to-install, simple-to-use interface exploring analyzing systematic effects related to blended in cosmological surveys such the Vera Rubin Observatory Legacy Survey Space Time (LSST). BTK has three main components:...
Abstract On the basis of several recent breakthroughs in fusion research, many activities have been launched around world to develop power plants on fastest possible time scale. In this context, high-fidelity simulations plasma behavior large supercomputers provide one main pathways accelerating progress by guiding crucial design decisions. When it comes determining energy confinement a magnetic device, which is key quantity interest, gyrokinetic turbulence are considered approach choice –...
The ATLAS detector has been designed for operation at CERN's Large Hadron Collider. includes a complex system of liquid argon calorimeters. This paper describes the architecture and implementation custom front end electronics developed readout
Within the EUROfusion MST1 work package, a series of experiments has been conducted on AUG and TCV devices to disentangle role plasma fueling shape for onset small ELM regimes. On both devices, regimes with high confinement are achieved if only two conditions fulfilled at same time. Firstly, density separatrix must be large enough (), leading pressure profile flattening separatrix, which stabilizes type-I ELMs. Secondly, magnetic configuration close double null (DN), reduction shear in...
Integrating the plasma core performance with an edge and scrape-off layer (SOL) that leads to tolerable heat particle loads on wall is a major challenge. The new European medium size tokamak task force (EU-MST) coordinates research ASDEX Upgrade (AUG), MAST TCV. This multi-machine approach within EU-MST, covering wide parameter range, instrumental progress in field, as ITER DEMO core/pedestal SOL parameters are not achievable simultaneously present day devices. A two prong adopted. On one...
Abstract The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance physics base of ITER and DEMO. Here, full tungsten wall is a key asset for extrapolating future devices. high overall heating power, flexible mix comprehensive diagnostic set allows studies ranging from mimicking scrape-off-layer divertor conditions DEMO at density fully non-inductive operation ( q 95 = 5.5, ) low density. Higher installed electron cyclotron...
The ATLAS detector has been designed for operation at CERN's Large Hadron Collider. includes a complex system of liquid argon calorimeters. electronics amplifying, shaping, sampling, pipelining, and digitizing the calorimeter signals is implemented on Front End Boards (FEBs). This paper describes design, implementation production FEBs presents measurement results from testing performed several stages during process.
Abstract An overview of recent results obtained at the tokamak ASDEX Upgrade (AUG) is given. A work flow for predictive profile modelling AUG discharges was established which able to reproduce experimental H-mode plasma profiles based on engineering parameters only. In center, theoretical predictions current redistribution by a dynamo effect were confirmed experimentally. For core transport, stabilizing fast ion distributions turbulent transport shown be important explain isotope and...
This paper presents the transport analysis of high density baseline discharges in 2016 experimental campaign Joint European Torus with ITER-Like Wall (JET-ILW), where a significant increase deuterium–deuterium (D–D) fusion neutron rate (~2.8 × 1016 s−1) was achieved stable neutral beam injection (NBI) powers up to 28 MW and low gas puffing. Increase T i exceeding e were produced for first time despite electron density; this enabled thermal reaction rate. As result, new record performance...
The measured D–D neutron rate of neutral beam heated JET baseline and hybrid H-modes in deuterium is found to be between approximately 50% 100% the expected from TRANSP code, depending on plasma parameters. A number candidate explanations for shortfall, such as fuel dilution, errors penetration effectively available power have been excluded. As dominated by beam–plasma interactions, 'neutron deficit' may caused a yet unidentified form fast particle redistribution. Modelling, which assumes...
Abstract In tokamaks, a leading platform for fusion energy, periodic filamentary plasma eruptions known as edge-localized modes occur in plasmas with high-energy confinement and steep pressure profiles at the edge. These could damage tokamak wall but can be suppressed using small three-dimensional magnetic perturbations. Here we demonstrate that these perturbations change topology just inside gradient region of We identify signatures island, their observation is linked to suppression modes....
The ATLAS detector has been built to study the reactions produced by Large Hadron Collider (LHC). includes a system of liquid argon calorimeters for energy measurements. electronics amplifying, shaping, sampling, pipelining, and digitizing calorimeter signals is implemented on set front-end electronic boards. boards are installed in crates mounted between calorimeters, where they will be subjected significant levels radiation during LHC operation. As result, all components used had an...
The design and unique feature of the first fast-ion loss detector (FILD) for Mega Amp Spherical Tokamak - Upgrade (MAST-U) is presented here. MAST-U FILD head mounted on an axially angularly actuated mechanism that makes it possible to independently adapt orientation [0°, 90°] radial position [1.40 m, 1.60 m] head, i.e., its collimator, thus maximizing velocity-space coverage in a broad range plasma scenarios with different q95. 3D geometry has been optimized detect losses from neutral beam...
Abstract A significant fraction of observed galaxies in the Rubin Observatory Legacy Survey Space and Time (LSST) will overlap at least one other galaxy along same line sight, a so-called “blend.” The current standard method assessing blend likelihood LSST images relies on counting up number intensity peaks smoothed image candidate, but reliability this procedure has not yet been comprehensively studied. Here we construct realistic distribution blended unblended through high-fidelity...