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View article: A novel discontinuous-Galerkin deterministic neutronics model for fusion applications: development and benchmarking
A novel discontinuous-Galerkin deterministic neutronics model for fusion applications: development and benchmarking Open
Neutron interactions in a fusion power plant play a pivotal role in determining critical design parameters such as coil-plasma distance and breeding blanket composition. Fast predictive neutronic capabilities are therefore crucial for an e…
View article: Effect of divertor on tritium breeding in HELIAS
Effect of divertor on tritium breeding in HELIAS Open
This study presents tritium breeding calculations for the five-period helical-axis advanced stellarator (HELIAS) using the Serpent2 code. To address the absence of a detailed divertor design, a simplified divertor model with a layered homo…
View article: A novel discontinuous-Galerkin deterministic neutronics model for Fusion applications: development and benchmarking
A novel discontinuous-Galerkin deterministic neutronics model for Fusion applications: development and benchmarking Open
Neutron interactions in a fusion power plant play a pivotal role in determining critical design parameters such as coil-plasma distance and breeding blanket composition. Fast predictive neutronic capabilities are therefore crucial for an e…
View article: Overview of Large Helical Device experiments of basic plasma physics for solving crucial issues in reaching burning plasma conditions
Overview of Large Helical Device experiments of basic plasma physics for solving crucial issues in reaching burning plasma conditions Open
Recently, experiments on basic plasma physics issues for solving future problems in fusion energy have been performed on a Large Helical Device. There are several problems to be solved in future devices for fusion energy. Emerging issues i…
View article: Global gyrokinetic analysis of Wendelstein 7-X discharge: unveiling the importance of trapped-electron-mode and electron-temperature-gradient turbulence
Global gyrokinetic analysis of Wendelstein 7-X discharge: unveiling the importance of trapped-electron-mode and electron-temperature-gradient turbulence Open
We present the first nonlinear, gyrokinetic, radially global simulation of a discharge of the Wendelstein 7-X-like stellarator, including kinetic electrons, an equilibrium radial electric field, as well as electromagnetic and collisional e…
View article: Proof-of-principle of parametric stellarator neutronics modeling using Serpent2
Proof-of-principle of parametric stellarator neutronics modeling using Serpent2 Open
This contribution presents neutron transport studies for the 5-period helical-axis advanced stellarator stellarator using the Serpent2 code. These studies utilize a parametric geometry model, enabling scans in neutronics modeling by varyin…
View article: Achieving stationary high performance plasmas at Wendelstein 7-X
Achieving stationary high performance plasmas at Wendelstein 7-X Open
This work reports on recent results on the search for high performance plasma scenarios at the magnetically confined stellarator fusion device Wendelstein 7-X. In four new designed scenarios, the development from transient toward stationar…
View article: Fast generation of parametric neutronic models for stellarators. Coupling HeliasGeom and GEOUNED
Fast generation of parametric neutronic models for stellarators. Coupling HeliasGeom and GEOUNED Open
The operation of the Wendelstein 7-X has highlighted stellarators as potential fusion power reactors. As a consequence, the pre-conceptual design of the next HELIAS stellarator has started in the framework of EUROfusion. During these first…
View article: Global gyrokinetic analysis of Wendelstein 7-X discharge: unveiling the importance of trapped-electron-mode and electron-temperature-gradient turbulence
Global gyrokinetic analysis of Wendelstein 7-X discharge: unveiling the importance of trapped-electron-mode and electron-temperature-gradient turbulence Open
We present the first nonlinear, gyrokinetic, radially global simulation of a discharge of the Wendelstein 7-X-like stellarator (W7-X), including kinetic electrons, an equilibrium radial electric field, as well as electromagnetic and collis…
View article: Analysis of implementing a rail-based maintenance system into a HELIAS 5-B device
Analysis of implementing a rail-based maintenance system into a HELIAS 5-B device Open
This paper reports on the analysis of potential rail-based maintenance systems when implemented into a Helical Advanced Stellarator (HELIAS) 5-B device. The main purpose of such a system would be to handle and exchange the internal vessel …
View article: A deterministic method for the fast evaluation and optimisation of the 3D neutron wall load for generic stellarator configurations
A deterministic method for the fast evaluation and optimisation of the 3D neutron wall load for generic stellarator configurations Open
The neutronic assessment of a fusion power plant design is usually a challenging and time-consuming task involving experts from several disciplines in order to assemble the geometry, source, as well as carry out computationally heavy Monte…
View article: A general stellarator version of the systems code PROCESS
A general stellarator version of the systems code PROCESS Open
We present modifications of the fusion reactor systems code Process that allow for a description of a general class of stellarator power plants, based on a stellarator coil-set and the respective MHD plasma equilibrium. For this, we modify…
View article: 2D coherence imaging measurements of C<sup>2+ </sup> ion temperatures in the divertor of Wendelstein 7-X
2D coherence imaging measurements of C<sup>2+ </sup> ion temperatures in the divertor of Wendelstein 7-X Open
For the first time, 2D ion temperature values are derived from coherence imaging spectroscopy (CIS) fringe contrast measurements by taking Zeeman line broadening effects into account during the analysis procedure of a spatial-heterodyne CI…
View article: Isotope effects on transport in LHD
Isotope effects on transport in LHD Open
Isotope effects are one of the most important issues for predicting future reactor operations. Large helical device (LHD) is the presently working largest stellarator/helical device using super conducting helical coils. In LHD, deuterium e…
View article: Turbulence Mechanisms of Enhanced Performance Stellarator Plasmas
Turbulence Mechanisms of Enhanced Performance Stellarator Plasmas Open
We theoretically assess two mechanisms thought to be responsible for the enhanced performance observed in plasma discharges of the Wendelstein 7-X stellarator experiment fueled by pellet injection. The effects of the ambipolar radial elect…
View article: Estimation of 14 MeV neutron rate from triton burn‐up in future W7‐X deuterium plasma campaigns
Estimation of 14 MeV neutron rate from triton burn‐up in future W7‐X deuterium plasma campaigns Open
Fast ion confinement is of major importance for the ignition of a burning fusion plasma. In future deuterium plasma campaigns of the Wendelstein 7‐X stellarator, W7‐X, the amount of triton burn‐up is one possible measure for fast ion confi…
View article: Investigation of the neoclassical ambipolar electric field in ion-root plasmas on W7-X
Investigation of the neoclassical ambipolar electric field in ion-root plasmas on W7-X Open
In this paper, the role of the radial electric field in high-performance ion-root plasmas on Wendelstein 7-X (W7-X) is examined and compared with neoclassical predictions. The W7-X stellarator is the world's first large-scale optimized ste…
View article: Increasing the density in Wendelstein 7-X: benefits and limitations
Increasing the density in Wendelstein 7-X: benefits and limitations Open
In stellarators, increasing the density is beneficial for the energy confinement. While there is no single reason for this observation, it is still very robust across different devices and this is reflected in the empirical energy confinem…
View article: Features of near and far scrape-off layer heat fluxes on the Wendelstein 7-X inboard limiters
Features of near and far scrape-off layer heat fluxes on the Wendelstein 7-X inboard limiters Open
The power fall-off length is used as a characteristic dimension to describe the power exhaust in the scrape-off layer (SOL) in magnetic confinement fusion devices. Measurements from the limiter campaign of the stellarator Wendelstein 7-X w…
View article: Effect of Electron Cyclotron Current Drive on the Ion Temperature in the Plasma Core Region of the Large Helical Device
Effect of Electron Cyclotron Current Drive on the Ion Temperature in the Plasma Core Region of the Large Helical Device Open
An indirect effect of the electron cyclotron current drive (ECCD) on the ion temperature in the plasma core region was observed in the Large Helical Device. The reference (no ECCD) discharge with a central ion temperature Ti0 of ∼3.0 keV i…
View article: Impurity transport studies at Wendelstein 7-X by means of x-ray imaging spectrometer measurements
Impurity transport studies at Wendelstein 7-X by means of x-ray imaging spectrometer measurements Open
This study reports on the effect of on- and off-axis heating power deposition on the impurity confinement in purely electron cyclotron resonance heated He plasmas on the stellarator Wendelstein 7-X. Therefore, impurity transport times τ I …
View article: Gyrokinetic microinstability analysis of high-<i>T</i> <sub>i</sub> and high-<i>T</i> <sub>e</sub> isotope plasmas in Large Helical Device
Gyrokinetic microinstability analysis of high-<i>T</i> <sub>i</sub> and high-<i>T</i> <sub>e</sub> isotope plasmas in Large Helical Device Open
Transport and confinement characteristics, and microinstabilities for high- and high- isotope plasmas in Large Helical Device are explored by using the gyrokinetic Vlasov simulation GKV with hydrogen isotope ions and real-mass kinetic elec…
View article: Energy confinement of hydrogen and deuterium electron-root plasmas in the Large Helical Device
Energy confinement of hydrogen and deuterium electron-root plasmas in the Large Helical Device Open
The dependence of the energy confinement and energy transport on the isotope mass is a long-standing open question in the stellarator community. With the recent upgrade of the Large Helical Device to allow for deuterium plasma operation, s…