S. Henderson
A5003662135- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Nuclear Materials and Properties
- Nuclear Physics and Applications
- Solar and Space Plasma Dynamics
- Laser-induced spectroscopy and plasma
- Metallurgical Processes and Thermodynamics
- Ion-surface interactions and analysis
- Metal and Thin Film Mechanics
- Particle Accelerators and Free-Electron Lasers
- Computer Graphics and Visualization Techniques
- Atomic and Molecular Physics
- Advanced battery technologies research
- Semiconductor materials and devices
- Vehicle Noise and Vibration Control
- Anomaly Detection Techniques and Applications
- Russia and Soviet political economy
- Geochemistry and Geologic Mapping
- Reservoir Engineering and Simulation Methods
Culham Science Centre
2015-2025
University of Strathclyde
2013-2025
Culham Centre for Fusion Energy
2013-2024
United Kingdom Atomic Energy Authority
2019-2024
National Centre for Nuclear Research
2021
Royal Military Academy
2020
University of Cagliari
2019
University of Liverpool
2019
Fermi National Accelerator Laboratory
2010
Naval Sea Systems Command
2002
Abstract Future fusion reactors require a safe, steady state divertor operation. The required detached operation is, in tokamaks with metal walls, usually achieved by seeding of impurities, such as nitrogen. With strong levels, the dominant radiation is emitted from small, poloidally localized volume inside confined region, vicinity X-point. location radiating observed to vary relative X-point depending on and power i.e. degree detachment. At ASDEX Upgrade tokamak, position radiator can be...
Abstract The tokamak à configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system address critical issues in preparation for ITER a fusion power plant. For the 2019–20 campaign configurational flexibility has been enhanced with installation of removable divertor gas baffles, diagnostic capabilities an extensive set upgrades new dual frequency gyrotrons. baffles reduce coupling between main chamber allow detailed...
Abstract STEP is a spherical tokamak prototype power plant that being designed to demonstrate net electric power. The design phase involves the exploitation of plasma models optimise fusion performance subject satisfying various physics and engineering constraints. A modelling workflow, including integrated core modelling, MHD stability analysis, SOL pedestal coil set free boundary equilibrium solvers, whole design, has been developed specify parameters develop viable scenarios. model JETTO...
Abstract In magnetic confinement thermonuclear fusion the exhaust of heat and particles from core remains a major challenge. Heat leaving are transported via open field lines to region reactor wall, called divertor. Unabated, particle fluxes may become intolerable damage Controlled ‘plasma detachment’, regime characterized by both large reduction in plasma pressure temperature at divertor target, is required reduce onto Here we report systematic approach towards achieving this critical need...
We present the first analysis of atomic and molecular processes at play during detachment in MAST-U Super-X divertor using spectroscopy data. Our indicates can be separated into four sequential phases: First, ionisation region detaches from target onset leaving a increased densities downstream. The plasma interacts with these molecules, resulting ions ($D_2^+$ and/or $D_2^- \rightarrow D + D^-$) that further react leading to Molecular Activated Recombination Dissociation (MAR MAD), which...
Future fusion reactors require a safe, steady-state divertor operation. With deep detachment, which is typically induced by impurity seeding, the radiation concentrates in small region at X-point or on closed flux surfaces above X-point. This so-called radiator (XPR) moves further inside confined with increasing seeding and location can be actively controlled. At AUG, parameter space for operation an XPR was significantly extended, using active feedback location. The observed nearly whole...
Abstract To mitigate the issue of plasma exhaust in reactor scale tight aspect ratio tokamaks such as Spherical Tokamak for Energy Production (STEP), a double-null (DN) configuration is thought to be advantageous over single-null (SN) configuration. However, practical control vertical stability will likely lead an oscillation around symmetry point, which may transient loading divertors. In this work we investigated impact disconnection two separatrices <?CDATA $\delta R_{\mathrm{sep}}$?>...
Abstract Using newly developed spectroscopic models to measure the divertor concentration of Ne and Ar, it is shown that experimental detachment threshold on ASDEX Upgrade with Ar-only mixtures Ar+N or Ne+N scales as expected in comparison an analytical equation derived by Kallenbach et al (2016 Plasma Phys. Control. Fusion 58 045013). However, found Ar radiates more efficiently less scrape-off layer than model predicts. By separately increasing neutral beam injection power cutting impurity...
Abstract Particle balance calculations are done for the seeding species N 2 , Ne, Ar, Kr as well He with aim of obtaining a realistic description divertor and core plasma impurity content. Experimental time traces main densities fitted by single, time-independent parameter v <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi/> <mml:mi>z</mml:mi> <mml:mo>,</mml:mo> <mml:mtext>in</mml:mtext> </mml:mrow> <mml:mtext>eff</mml:mtext>...
Success of the UK’s Spherical Tokamak for Energy Production (STEP) programme requires a robust plasma control system. This system has to guide from initiation burning phase, maintain it there, produce desired fusion power duration and then terminate safely. be done in challenging environment with limited sensors without overloading plasma-facing components. The parameters operational regime STEP prototype will very different tokamaks, which are presently operation. During burn,...
STEP is a spherical tokamak prototype power plant that being designed to demonstrate net electric power. The design phase involves the exploitation of plasma models optimise fusion performance subject satisfying various physics and engineering constraints. A modelling workflow, including integrated core modelling, MHD stability analysis, SOL pedestal coil set free boundary equilibrium solvers, whole design, has been developed specify parameters develop viable scenarios. model JETTO used...
Abstract The Tokamak à Configuration Variable (TCV) tokamak is in the midst of an upgrade to further its capability investigate conventional and alternative divertor configurations. To that end, modular removable gas baffles have been installed decrease coupling between plasma core. primarily seek suppress transit recycling neutrals closed flux surfaces. A first experimental campaign with has shown baffled remains compatible a wide range configurations including snowflake super- X divertors....
Abstract This paper reports the first experiment carried out in deuterium–tritium addressing integration of a radiative divertor for heat-load control with good confinement. Neon seeding was time D–T plasma as part second campaign JET its Be/W wall environment. The technical difficulties linked to re-ionisation heat load are reported T and D–T. compares impact neon on plasmas their D counterpart detachment, localisation radiation, scrape-off profiles, pedestal structure, edge localised modes global
Abstract Building on prior analysis of ASDEX Upgrade (AUG) experiments (Henderson et al 2023 Nucl. Fusion 63 086024), this study compares simple analytical formula predictions for divertor detachment onset and reattachment timescales in JET experiments. Detachment primarily scales with neutral pressure, impurity concentration, power directed to the targets, machine size, integral perpendicular decay length. experiments, focusing seeding mixtures Ne Ar, align predictions. Radiation...
Abstract JET returned to deuterium-tritium operations in 2023 (DTE3 campaign), approximately two years after DTE2. DTE3 was designed as an extension of JET's 2022-2023 deuterium campaigns, which focused on developing scenarios for ITER and DEMO, integrating in-depth physics understanding control schemes. These were evaluated with mixed D-T fuel, using the only remaining tritium-capable tokamak until its closure 2023. A core-edge-SOL integrated H-mode scenario developed tested D-T, showing...
The mega amp spherical tokamak (MAST) was a low aspect ratio device (R/a = 0.85/0.65 ~ 1.3) with similar poloidal cross-section to other medium-size tokamaks. physics programme concentrates on addressing key issues for the operation of ITER, design DEMO and future tokamaks by utilising high resolution diagnostic measurements closely coupled theory modelling significantly advance our understanding. An empirical scaling energy confinement time that favours higher power, lower collisionality...
Partial detachment is the desired regime for baseline burning plasma scenario in ITER and next-step devices, as it allows to dissipate majority of energy carried by charged particles through scrape-off-layer (SOL) thus avoids localised heat flux deposition divertor region.The COMPASS tokamak equipped with an open has a relatively short connection length, both factors being unfavourable access detachment.As such, only approach naturally detached operation at very high lineaveraged densities...
The Tokamak à Configuration Variable (TCV) has recently been equipped with gas baffles to increase its divertor closure for a broad range of magnetic geometries. First experimental results reported in Reimerdes et al. (2021) demonstrated compatibility geometries and confirmed the main design constraints baffles, particular an increased neutral pressure. present article presents more in-depths analysis extended experiments this first baffle assessment on TCV boundary plasma. It is shown that...
Experiments on trace argon impurity transport in L-mode discharges were performed Korea superconducting tokamak advanced research (KSTAR) with electron cyclotron resonance heating (ECH). Ar emission was measured by soft x-ray (SXR) arrays and vacuum UV (VUV) diagnostics. A significant reduction the core emissivity observed ECH. The largest on-axis became smaller outward positions. diffusivity convection velocity of obtained analysis SXR data SANCO code for ECH non-ECH shots. In case, both...
Ray-tracing techniques are applied to bolometry, a diagnostic where the finite collection volume is particularly sensitive machine and detector configuration. A technique presented that can handle arbitrarily complex aperture collimator geometries, neglecting reflection effects. Sight lines from ASDEX Upgrade bolometer foils were ray-traced with path tracing algorithm, optical represented by statistical bundle of ray paths connecting foil surface slit geometry. By using full 3D model for box...
Analytical expressions for the divertor radiation around onset of detachment based on neutral pressure and upstream separatrix density are tested against measurements strongly nitrogen seeded high confinement mode (H-mode) discharges in ASDEX Upgrade. The is used as a key experimental parameter far possible, since it can be regarded engineering balance puffing pumping. For tentative extrapolation to future tokamak power plants, limits set by maximum core impurity concentration via burn...
Abstract The capabilities of the newly installed divertor Thomson Scattering (DTS) diagnostic (Kurzan et al 2021 J. Inst. 16 C09012) at ASDEX Upgrade (AUG) have been demonstrated by measuring 2D electron densities n e and temperatures T from attached to fully detached conditions in L- H-mode. collected dataset is a breakthrough for studies AUG which such measurements so far missing. Besides highlighting strengths limits DTS system, this work provides confirmations new insights into...