-
Dominic Power (LLNL / UKAEA)Turbulence codesRegular talk
Snowflake divertor (SFD) experiments show enhanced radial transport near the X-points, more than can be explained by standard 2D edge transport modelling (i.e. with poloidally uniform diffusion coefficients and without drifts). While 3D effects may be relevant here, several 2D transport mechanisms have been proposed in the literature which could explain this phenomenon: 1) a region of enhanced...
Go to contribution page -
Wim Van Uytven (KU Leuven (EU))Mean-field codesRegular talk
In plasma boundary modelling, fluid neutrals offer several practical disadvantages compared to their more accurate kinetic Monte Carlo counterparts. They are typically much faster, and their deterministic nature is a major benefit when doing optimization or when coupling to plasma turbulence codes.
Besides missing kinetic effects, fluid neutral models are typically also lagging behind with...
Go to contribution page -
George HoltMean-field codesRegular talk
Accurate scrape-off layer (SOL) modelling is essential for tokamak heat and particle exhaust studies, supporting experiment interpretation, scenario optimisation, and reactor design. Existing methods require a compromise between speed and fidelity: analytical models are fast but simplified, while comprehensive simulations capture plasma and neutral physics but are too costly for...
Go to contribution page -
Tengfei Tang (Agency of Science, Technology and Research)Kinetic neutralsRegular talk
Tungsten sputtering, redeposition, and transport in the divertor region are key processes governing impurity migration and contamination of the plasma core in fusion devices. Predictive modelling of these processes requires a coupled description of edge-plasma transport, sheath acceleration, plasma–surface interaction, sputtering, ionization, recombination, and impurity redeposition. In this...
Go to contribution page -
Naomi Carey (UKAEA)Research Software EngineeringLightning talk + poster
Surrogate enable the rapid evaluation of plasma quantities across different divertor operating conditions. Building on previous work on surrogate modelling for geometry, fuelling and impurity seeding studies, this work focuses on the continued development and evaluation of deep learning-based surrogates trained to predict 2D plasma variables from simulation inputs (both 1d and 2D).
We...
Go to contribution page -
Owen Parry (UKAEA)Mean-field codesLightning talk + poster
Molecules are expected to play a critical role in the physics of detachment in tokamak divertors.
Go to contribution page
Fluid modelling of molecular species has been a longstanding and conspicuous absentee from the Hermes-3 feature list, but recent changes to the code have greatly simplified its implementation.
The handling of chemical reactions has been substantially overhauled, introducing a framework that... -
Mr Jeremy J. Williams (KTH Royal Institute of Technology)Research Software EngineeringRegular talk
Particle-in-Cell (PIC) Monte Carlo (MC) simulations of the plasma edge play an important role in magnetic confinement fusion research, providing insights into plasma-surface interactions and plasma, impurity and neutral particle transport, relevant to both present and future fusion devices. As plasma simulations continue to increase in size and complexity, efficiently exploiting modern...
Go to contribution page -
Mike KryjakMean-field codesRegular talk
Hermes-3 is an open-source fluid edge plasma code written using the BOUT++ framework. Building on the features of SD1D, Hermes-2 and STORM, it enables self-consistent simulation of scrape-off layer plasmas in 1D, 2D and 3D for both steady-state and unsteady/turbulent regimes. In this work, we present an update on several activities contributing towards improved neutral model capability in the...
Go to contribution page -
Annika Stier (IPP-Greifswald)Mean-field codesLightning talk + poster
As part of the effort to establish Hermes-3 as a simulation tool for the stellarator edge and scrape-off layer, we examine the current implementation of the advanced fluid neutral model.
Go to contribution page
Due to the toroidal asymmetry of the strike line, stellarator scenarios could be more sensitive to artificial anisotropies in the neutral transport than tokamaks. We therefore evaluate the neutral anisotropy... -
Sid Leigh (UKAEA)Mean-field codesLightning talk + poster
We present the benchmarking of one-dimensional (1D) simulations comparing a newly developed 1D exhaust code RMK_REX [1] with the modelling suite SOLPS-ITER [2]. RMK_REX is developed in the ReMKiT1D framework [3] for fluid-kinetic and collisional-radiative modelling, with the aim of simulating detached plasmas with non-local electron effects. The benchmark serves to calibrate RMK_REX to...
Go to contribution page -
Andrei Ludvig-Osipov (UKAEA)Kinetic neutralsRegular talk
The plasma behaviour in the exhaust region of tokamaks is strongly influenced by atomic and molecular processes, as experimentally demonstrated on, e.g., MAST-U [1], JET, AUG [2], Alcator C-Mod [3]. Faithful representation of these processes is therefore necessary for robust exhaust simulation capability. However, fully-resolved atomic and molecular reaction systems typically include hundreds...
Go to contribution page -
Amit Kharwandikar (Max-Planck-Institut für Plasmaphysik, Greifswald)Mean-field codesLightning talk + poster
The development of a viable plasma exhaust solution is one of the principal challenges on the path towards stellarator fusion reactors. While the island divertor of Wendelstein 7-X (W7-X) has demonstrated excellent performance in terms of detachment and steady-state operation, its present open geometry limits neutral compression and particle exhaust. A closed divertor configuration is...
Go to contribution page -
Alessandro Geraldini (University of York)Turbulence codesLightning talk + poster
When using a fluid model to simulate the plasma in the Scrape-Off Layer, boundary conditions are imposed at the entrance of the boundary layer next to the solid targets, where the model assumptions fail. This boundary layer reflects most electrons away from the target. With finite ion temperature, the largest length scale in the boundary layer is the collisional mean free path (along the...
Go to contribution page -
Dr Ben Dudson (LLNL)Turbulence codesRegular talk
We report on progress in modeling of plasma drifts and 3D turbulence using Hermes-3, in tokamak and stellarator configurations. During the past year improvements have been made to models for the diamagnetic and polarization currents, ion viscosity and energy conservation. Tokamak applications include simulation of turbulence in NSTX and NSTX-U configurations, with comparison to experimental...
Go to contribution page -
Stijn Kobussen (DIFFER, Dutch Institute for Fundamental Energy Research)Kinetic neutralsRegular talk
The safe and controlled exhaust of heat and particles from magnetically confined fusion plasmas requires having dynamic information about the system. On present-day reactors, this information is obtained using system identification experiments, which involve perturbing the gas injection rate and observing the Scrape-Off-Layer (SOL) response in the frequency domain. However, this strategy is...
Go to contribution page -
Steven Thomas (MIT PSFC)Mean-field codesLightning talk + poster
Steven Thomas1,*, Jerry W. Hughes1, Alex Tookey2, Davis Easley3, Yacopo Damizia4,
Bart Lomanowski3, Saskia Mordijck4, Ekin Öztürk4, Scott Silburn2,
and the MAST Upgrade Team2,†1MIT Plasma Science and Fusion Center, Cambridge, MA 02139, USA
Go to contribution page
2UKAEA, Culham Campus, Abingdon, Oxfordshire, OX14 3DB, UK
3Oak Ridge National Laboratory, Oak Ridge, TN 37831-6169, USA
4William & Mary,... -
Mr Tom Ashton-Key (Imperial College London)Turbulence codesLightning talk + poster
Hermes-3 is a multi-component plasma fluid code based on the BOUT++ framework [1] which simulates turbulence in the edge region and scrape-off-layer of tokamak plasmas with full 3D diverted tokamak geometry. The effect of turbulent magnetic fluctuations due to local turbulent currents has been implemented in Hermes-3, including ‘magnetic flutter’, how local magnetic fluctuations impact the...
Go to contribution page -
Dr Patrick Tamain (CEA)Turbulence codesKeynote talk
Predictive modelling of plasma edge and divertor physics is a key challenge for ITER and future fusion power plants, where narrow operational margins require self-consistent treatment of turbulence, neutrals, magnetic geometry, and plasma-wall interactions. The TSVV3 project was established to advance European edge fluid turbulence modelling tools towards reactor-relevant predictive...
Go to contribution page -
Sebastian Ruiz Gonzalez (University of York)Research Software EngineeringLightning talk + poster
The divertor problem is one of the biggest ongoing challenges in the fusion energy sector. The magnetic geometry and topology of the divertor region in tokamaks significantly influences plasma edge dynamics as well as heat and particle exhaust.[1] Advanced divertor configurations, like the snowflake (SF) divertor, offer advantages in mitigating heat loads and enhancing plasma performance.[2]...
Go to contribution page -
Dr Brendan Shanahan (MIT Plasma Science and Fusion Center)Turbulence codesRegular talk
Toroidal magnetic confinement fusion experiments require a rotational transform
Go to contribution page
to achieve adequate confinement. This rotational transform can be achieved
via any combination of internal plasma currents, torsion of the magnetic axis,
and the toroidal rotation of the plasma cross section. Internal currents can lead
to current-driven instabilities, and therefore the first stellarators... -
Jack Gabriel (William & Mary)Kinetic neutralsRegular talk
In this talk, GUERNICA, a new continuum kinetic neutral code, is presented for the simulation of atomic hydrogen transport in fusion edge plasmas, solving the Boltzmann equation with charge exchange, ionization and elastic neutral-neutral collisions. Neutral atoms strongly influence tokamak edge and divertor physics through fueling, momentum exchange and volumetric power loss [1]. Accurate...
Go to contribution page -
Yichen Fu (Columbia University)Turbulence codesRegular talk
Laboratory dipole confinement was proposed by Hasegawa in 1987 as a possible route to fusion-relevant plasmas and has been explored in levitated-dipole experiments such as LDX, RT-1, and the recent Junior device. A dipole magnetic field is characterized by its strong magnetic-flux expansion, i.e., the magnetic field strength varies strongly along a field line, which poses challenges for...
Go to contribution page -
Stefan Tirkas (Lawrence Livermore National Laboratory)Turbulence codesRegular talk
Realizing commercially viable fusion power plants (FPPs) demands whole-device modeling efforts which integrate high‐fidelity plasma simulations with engineering systems and design capabilities. Among the most pressing challenges are the accurate prediction of heat and particle exhaust in the divertor region and the self‐consistent treatment of plasma–neutral and plasma–wall interactions in the...
Go to contribution page -
Sidney Williams (University of California San Diego)Mean-field codesRegular talk
Despite tokamaks being primarily treated as axisymmetric beasts, many aspects of actually running such a machine are inherently nonaxisymmetric. This includes error fields, magnetic ripple, and even Edge Localized Mode-suppressing (ELM-suppressing) Resonant Magnetic Perturbations (RMPs). Each of these effects are extremely important to consider while the fusion field is moving towards next...
Go to contribution page -
Vera Oberhauser (UKAEA)Mean-field codesLightning talk + poster
Magnetic flux expansion in the scrape-off layer (SOL) is a critical mechanism for spreading exhaust heat loads across divertor target surfaces, and its accurate modelling is essential for predicting performance in present and next-generation devices. This phenomenon is typically modelled using fluid codes, which incorporate flux expansion geometrically through area factors in the governing...
Go to contribution page -
Jamie Dunsmore (MIT)Kinetic neutralsRegular talk
We present KN1DPy, a Python translation of KN1D, a spatially 1D kinetic neutral transport code that was originally written in IDL to model gas fuelling on the Alcator C-Mod tokamak. Given input profiles of electron density, $n_e$, and temperature, $T_e$, in the scrape-off-layer and on closed flux surfaces, KN1D solves the Boltzmann Equation to obtain the distribution functions for atomic and...
Go to contribution page -
Lin Shih (University of York)Mean-field codesLightning talk + poster
Understanding the mechanism of edge transport in magnetic confinement fusion devices is critical for future reactors, as it determines how effectively high heat loads can be exhausted to achieve the sustainability of the devices.
In this work, the multi-fidelity exhaust code Hermes-3 [1] is employed to model scrape-off layer (SOL) transport using a fluid framework, solving the Braginskii...
Go to contribution page -
Will Saunders (UKAEA)Research Software EngineeringRegular talk
Simulation of fusion plasma often requires representations of non-Maxwellian distributions. A common method is to represent the distribution function as a collection of individual particles where the state of each particle evolves over time. In this talk we describe NESO-Particles (NP) which is a performance portable framework for describing particle based algorithms.
NP provides users with...
Go to contribution page -
Joseph Bryant (Tokamak Energy)Mean-field codesRegular talk
Heading ##Molecular processes are known to influence divertor detachment, but conventional effective-rate models assume vibrationally excited molecules remain in local equilibrium and neglect their transport [1, 2]. In this work, vibrationally resolved D2 simulations using the X1EXT molecular database are applied to both simplified divertor-leg and full-device MAST Upgrade Super-X...
Go to contribution page -
Ryoko Osawa (UKAEA)Mean-field codesRegular talk
We have been using the SOLPS-ITER code to design and optimise the divertor for STEP (Spherical Tokamak for Energy Production). While this modelling has yielded important physical insights — such as the impacts of fuelling locations and dome shape — it has also highlighted significant numerical challenges. These issues introduce additional uncertainties on top of existing variances driven by...
Go to contribution page -
Andreas Holm (Lawrence Livermore National Laboratory)Mean-field codesRegular talk
The 2D multi-fluid edge-plasma code UEDGE employs the fully time-implicit NKSOL Jacobian-Free Newton-Krylov (JFNK) solver (P.N. Brown, Y. Saad, SIAM J. Sci. Comput. 11, 1990). UEDGE solves a set of coupled plasma-neutral equations delivering 10–100$\times$ speedup compared explicitly-coupled fluid-plasma/kinetic-neutral code and numerical convergence to steady-state when including magnetic and...
Go to contribution page -
Dr Yannick Marandet (Aix-Marseille University / CNRS)Kinetic neutralsKeynote talk
The particle, momentum and energy exchanges between the plasma and the neutral gas from recycling are key aspects of divertor physics. Atoms and molecules are often not in a collisional regime and a kinetic description is required to get transport right. In detached regimes, where the temperature in the divertor drops below a few eVs, the complexity of the reaction channels for neutrals...
Go to contribution page -
Sarah Newton (UKAEA)Research Software EngineeringRegular talk
The dynamics of the edge of tokamak plasmas is understood to be sensitive to the electric field profile. Meanwhile modelling the long-wavelength component of the radial electric field is challenging for core physics, but essential to understand the rotation profile.
The moment-kinetics approach to evaluating transport was introduced under the Excalibur project ([report TN-11][1]). This...
Go to contribution page -
Andreas Stegmeir (Max Planck Institute for Plasma Physics)Turbulence codesKeynote talk
An overview of the GRILLIX [1] code is presented, a three-dimensional turbulence simulation code for the self-consistent modeling of the plasma edge and scrape-off layer. The code is based on a global drift-reduced fluid model coupled to a three-moment fluid neutral model. It employs the Flux-Coordinate Independent (FCI) approach, enabling efficient treatment of complex magnetic geometries,...
Go to contribution page -
James EdgeleyTurbulence codesLightning talk + poster
UKAEA's edge code PENKNIFE is under development, incorporating the finite element framework Nektar++ and the reactions library VANTAGE. The code is designed to be used with modern hardware, exploiting the higher arithmetic intensity of finite element methods and the GPU parallelism of NESO-Particles for improved performance. A range of features have been implemented, encompassing a hierarchy...
Go to contribution page -
Jony Castagna (UKRI-STFC Hartree Centre)Research Software EngineeringRegular talk
Hermes-3, a multi-fluid plasma simulation framework built on BOUT++, is currently being ported to GPUs using the RAJA performance portability layer and CUDA. This work builds upon the GPU infrastructure previously developed at Lawrence Livermore National Laboratory (LLNL) for BOUT++, enabling the reuse of established programming models and optimization strategies.
The porting effort is...
Go to contribution page -
Tobias Tork (IPP Greifswald)Mean-field codesRegular talk
Particle drifts play a crucial role in understanding of the edge physics of current and future fusion
Go to contribution page
devices. While tokamak simulations routinely include drift effects, they have been largely neglected
in stellarator simulations until now. Advancements in BOUT++ enable the efficient simulation
of stellarator geometries. Hermes-3 is a plasma fluid model for the edge of fusion devices... -
Gregory Parker (UC Berkeley)Kinetic neutralsRegular talk
In recent work, we introduced a novel multi-level Monte-Carlo scheme for kinetic simulations of neutral particles in plasmas near the isotropic cross-section limit. Of particular interest is the case of edge plasmas in detatched or near-detached regimes. The multi-level scheme in this case is based on a propagator formalism enumerating discrete charge-exchange collision events. This scheme...
Go to contribution page -
Chris MacMackin (UK Atomic Energy Authority)Research Software EngineeringLightning talk + poster
Hermes-3 is a multifluid plasma simulation code, built on BOUT++. It is used for simulating transport and turbulence at the edge of magneticically-confined plasmas. It uses a system of modular components which make it highly flexible. I have provide research software engineering skills to support the ongoing development and optimisation of Hermes-3 and BOUT++. I will be presenting the work I...
Go to contribution page -
Dr Frederic Schwander (Aix-Marseille University / M2P2)Mean-field codesKeynote talk
Fluid transport simulations based on mean-field quantities, with the averaged out turbulence fluctuations being modelled, remain a standard in the international community when considering engineering studies of tokamak relevant configurations (for a review of state-of-the-art transport codes, see Schwander et al. 2024).
Go to contribution page
In the perspective of enhancing computational efficiency and expanding... -
Ed Threlfall (UKAEA)Turbulence codesRegular talk
The finite element method (FEM) concerns the numerical discretization of continuum partial differential equations. This talk briefly covers some applications of FEM to problems in plasma physics, including strongly orthotropic transport and plasma turbulence. We will emphasize the potential advantages of FEM in terms of numerical properties – stability, rapid convergence, and the suppression...
Go to contribution page -
Mantas Abazorius (United Kingdom Atomic Energy Authority)Mean-field codesLightning talk + poster
In magnetic confinement fusion devices, the divertor is often negatively charged because electrons are more mobile and are preferentially captured by the divertor. This negative charge is shielded by a positively charged Debye sheath. In magnetised plasmas, another layer of width of the order of the ion gyroradius, known as the magnetic presheath, forms on top of the Debye sheath. In this...
Go to contribution page -
John Lloyd Baker (University of York, UKAEA)Mean-field codesLightning talk + poster
\noindent The STEP program run by UK Fusion Energy Ltd (UKFE, UKAEA group) aims to deliver a tritium self sufficient prototype fusion power plant generating 100 MW net electric power based on the spherical tokamak concept. The compact spherical geometry of STEP's SPP-2 design raises significant exhaust challenges, with powers crossing the separatrix reaching $P_\text{sep} \approx110 -...
Go to contribution page -
Davide Mancini (EPFL)Kinetic neutralsRegular talk
We present KINDNES (KINetic Deterministic NEutral Solver), a tool for solving the kinetic Boltzmann equation applied to neutral particle dynamics in the boundary plasma of tokamaks and stellarators. Originally developed as the neutral model within the GBS turbulence code, KINDNES is now developed as a standalone library.
Go to contribution page
Neutral particles play a central role in edge plasma physics, governing... -
Mr Daniel Maris (DIFFER)Kinetic neutralsKeynote talk
A few years ago, the nonlinear extended MHD code JOREK [2] has been extended with a dedicated kinetic neutral model [3], opening up the possibility to transiently model the interplay between edge-plasma and plasma-wall interactions and the plasma processes for which JOREK is well known such as ELMs, disruptions and RE beams, where previously these worlds could not be self-consistently combined...
Go to contribution page -
David Moulton (UKAEA)Kinetic neutralsLightning talk + poster
We present transient simulations of the MAST-U tokamak using the SOLPS-ITER model, operated in time-dependent mode and including time-dependent kinetic neutrals. Given the expected audience, we focus on the numerical requirements and challenges to run SOLPS-ITER in time-dependent mode, as well as the separate validation of the Eirene and B2.5 codes.
Go to contribution page -
Nassim Maaziz (IPP-Greifswald)Mean-field codesLightning talk + poster
The island divertor concept was proposed for power and particle exhaust in low-shear stellarators, such as Wendelstein 7-X. So far low downstream density has been experimentally measured. Stronger scaling of the downstream density is necessary to ensure the reactor-relevance of the island divertor in terms of particle exhaust. Numerical studies of the island divertor SOL require 3D codes,...
Go to contribution page -
David Bold (IPP Greifswald)Turbulence codesLightning talk + poster
In order to model the scrape-off layer of a fusion device,
Go to contribution page
traditionally field aligned codes have been used. For stellarators, this is not feasible, and the flux coordinate independent approach (FCI) is used.
Aligning the grid with the boundary is challenging, and generating
body fitted, structured grids restricts the homogeneity and
orthogonality of the grid, making numerical integration... -
Matteo Moscheni (Gauss Fusion GmbH, Parkring 29, 85748 Garching bei München, Germany)Kinetic neutralsRegular talk
Kinetic neutral transport remains one of the least reducible components of fusion exhaust modelling. While coupled plasma-edge tools such as SOLPS-ITER/EIRENE remain the standard route for integrated divertor simulations, standalone kinetic-neutral calculations provide a complementary way to isolate rarefied-gas effects, test boundary-condition assumptions, and interpret neutral transport...
Go to contribution page -
Stefan Mijin (UKAEA)Kinetic neutralsRegular talk
UKAEA (United Kingdom Atomic Energy Authority), Culham Campus, Abingdon, Oxfordshire, OX14 3DB, UK.
The accurate simulation of neutral particles in the tokamak exhaust has been a topic of research across many decades, with the primary numerical approach being Markov Chain Monte Carlo methods, widely used in linear transport problems[1,2]. Historically, neutral-neutral collisions have been...
Go to contribution page
Choose timezone
Your profile timezone: