A5082802109- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Laser-Plasma Interactions and Diagnostics
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Solar and Space Plasma Dynamics
- Nuclear reactor physics and engineering
- Astro and Planetary Science
- Scientific Measurement and Uncertainty Evaluation
- Advanced Data Storage Technologies
- Neural Networks and Applications
- Seismic Imaging and Inversion Techniques
- NMR spectroscopy and applications
- Particle accelerators and beam dynamics
- Laser-induced spectroscopy and plasma
- Scientific Research and Discoveries
- High-pressure geophysics and materials
- Seismic Waves and Analysis
Technical University of Denmark
2020-2024
Abstract The fast-ion distribution function in fusion plasmas can be inferred by inverting Doppler-shifted measurements from diagnostics. full parametrised three constants of motion with the addition a binary index. However, limited number measurements, cogent prior information must added to regularise inverse problem, enabling reconstruction function. In this paper, we demonstrate how incorporate wave-particle interactions ion cyclotron range frequencies (ICRF) as future ITER tokamak test...
Abstract We present a new version of the FILDSIM code (Galdon-Quíroga et al 2018 Plasma Phys. Control. Fusion 60 105005), which significantly refines modelling fast-ion loss detector (FILD) signal. demonstrate that FILD weight functions computed using this are more accurate relative to synthetic benchmarks than those previous version. Thus, enables higher-quality velocity-space sensitivity and reconstructions. validate improvements on experimental data from discharge #75620 at TCV....
Abstract The fast-ion phase-space distribution function in axisymmetric tokamak plasmas is completely described by the three constants of motion: energy, magnetic moment and toroidal canonical angular momentum. In this work, observable regions constants-of-motion phase-space, given a diagnostic setup, are identified explained using projected velocities fast ions along lines-of-sight as proxy for several diagnostics, such <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Abstract We compute reconstructions of 4D and 5D fast-ion phase-space distribution functions in fusion plasmas from synthetic projections these functions. The originating neutral beam injection (NBI) at TCV Wendelstein 7-X (W7-X) full, half, one-third energies can be distinguished particle densities each component inferred based on 20 spectra projected velocities 680 W7-X. Further, we demonstrate that an expansion into a basis slowing-down is equivalent to regularization using physics as...
Abstract In the JET DTE2 deuterium-tritium campaign, neutron diagnostics were employed to measure 14 MeV neutrons originating from D(T,n) 4 He reactions. discharge 99965, a diamond matrix detector (KM14) and magnetic proton recoil (MPRu) with vertical an oblique line-of-sight used, respectively. At timepoints of interest, significant decrease in expected diagnostic signals can be observed as electromagnetic wave heating ion cyclotron range frequencies (ICRF) is switched off. Utilizing only...
Abstract Tomographic reconstructions of a 3D fast-ion constants-of-motion phase-space distribution function are computed by inverting synthetic signals based on projected velocities the fast ions along diagnostic lines sight. A spectrum is key element formation in D-alpha spectroscopy, collective Thomson scattering, and gamma-ray neutron emission it can hence serve as proxy for any these. The functions parameterised three constants motion, kinetic energy, magnetic moment toroidal canonical...
Abstract We present a method to analytically compute gamma-ray spectra generated via two-step fusion reactions, where is emitted from the excited nucleus in first step of reaction. If one reactant energetic and other at rest, reaction can be treated analytically. The second step, which emission nucleus, always model we derive tested against established forward-model code GENESIS, obtaining very satisfactory results.&#xD;Our fully analytic treatment far less expensive technique than...
Abstract We demonstrate 2D reconstructions of the fast-ion velocity distribution from two-view D-alpha (FIDA) measurements at EAST tokamak. By expressing in a basis relying on slowing-down process fusion plasmas, smoothness and velocity-space resolution are improved. reconstruct distributions fast ions born simultaneous co- counter-current neutral beam injection detect expected distinct change birth pitch when comparing discharges utilizing different injectors. For purely co-current...
This paper introduces a new model to find the velocity-space location of energetic ions generating ion cyclotron emission (ICE) in plasmas. ICE is thought be generated due inverted gradients v⊥ direction velocity distribution function or anisotropies, i.e., strong pitch direction. Here, we invert synthetic spectra from first principles PIC-hybrid computations locations these ICE-generating space terms probability function. To this end, compute 2D weight functions based on magnetoacoustic...
Abstract Fast ions in the MeV-range can be diagnosed by neutron emission spectroscopy (NES) and gamma-ray (GRS). In this work, we present orbit weight functions for one-step fusion reactions, using NES GRS diagnostics on perpendicular oblique lines-of-sight (LOS) at Joint European Torus (JET) as examples. The allow us to express sensitivities of terms fast-ion (FI) orbits used swiftly reproduce synthetic signals that have been computed established codes. For diagnostically relevant energies...
Fast ions in fusion plasmas often leave characteristic signatures the plasma neutron emission. Measurements of this emission are subject to phase-space sensitivity diagnostic, which can be mapped using weight functions. In paper, we present orbit functions for TOFOR and NE213 diagnostics at Joint European Torus, mapping their 3D space. Both highly sensitive fast that spend a relatively large fraction transit times inside viewing cone diagnostic. For most energies, is found potato orbits...
Abstract Fast-ion loss detectors (FILDs) are crucial for analyzing fast-ion dynamics in magnetically confined fusion plasmas. A core challenge is to derive an accurate ion velocity distribution, requiring treatment of thousands remapped camera frames a full discharge. The ill-posed nature this task necessitates regularization with well-chosen parameter and computationally efficient methods. In work, we introduce the ‘resolution principle,’ novel criterion selecting optimal parameter,...
The relationship between simulated ion cyclotron emission (ICE) signals s and the corresponding 1D velocity distribution function fv⊥ of fast ions triggering ICE is modeled using a two-layer deep neural network. network architecture (number layers number computational nodes in each layer) hyperparameters (learning rate learning iterations) are fine-tuned bottom-up approach based on cross-validation. Thus, optimal mapping gs;θ terms nodes, layers, values hyperparameters, where θ learned model...
Accurate distribution transforms between common 4D axisymmetric tokamak guiding center coordinates {energy,pitch,R,Z}, and orbit-space (made up of a particle's kinetic energy E, maximum radius in the Rm, pitch at point pm, time-normalised phase τ=t/torbit) are vital for verification implementation orbit tomography. These have proven difficult past due to discontinuities across topological boundaries orbit-space. In this work we exhaustively investigate these transforms, comparing existing...
In fusion plasma physics, the large-scale trajectories of energetic particles in magnetic confinement devices are known as orbits. To effectively and efficiently be able to work with orbits, Orbit Weight Computational Framework (OWCF) was developed. The OWCF constitutes a set scripts, functions applications capable computing, visualizing working quantities related fast-ion (FI) orbits toroidally symmetric devices. current version is highly integrated DRESS code, which enables compute analyze...
We present a fully relativistic analytical model for calculating synthetic spectra from beam–target fusion reactions. When the target particle is assumed at rest, Monte Carlo sampling of reactant velocities can be avoided, and spectrum computations are considerably faster. A treatment additionally gives more insight into formation. The formulation now makes it possible to handle massless particles in model, example one-step gamma-ray reactions, results corroborated by simulations established codes.
The fast-ion phase-space distribution function in the magnetic fusion devices is always underdiagnosed, and every new diagnostic should be carefully assessed before installation to minimize redundancies measurements maximize information from yet undiagnosed part of phase space function. Here, we present a novel method assessing added value considered diagnostic, taking actual geometry an existing set diagnostics into account. based on reformulation weight functions constants motion (COM). We...
Abstract An important step on the way to future fusion power plants was 2021 deuterium-tritium experimental campaign (DTE2) at Joint European Torus (JET), in which crucial DT physics investigated. In this study, we have reconstructed fast-ion deuterium distribution function JET discharge 99971 broke former energy record. It is first time that has been from data a discharge. The reconstruction shows anisotropic, with bias towards co-going ions (p>0). likely peaks (E) around 60-70 keV and...
Abstract We present a fully analytical model for calculating energy spectra of neutrons generated by fusion reactions involving fast ion, or beam, and stationary target, in magnetic plasmas. For moving along the line-of-sight detector, neutron spectrum is given an expression usual differential cross section. This makes several orders magnitude faster than ordinary Monte Carlo simulations free any related statistical noise. &#xD;Additionally, description reaction physics provides much...
This paper characterizes the correlation of simultaneous measurements with different fast-ion H-alpha (FIDA) spectroscopy sightlines on Wendelstein 7-X. Using a collisionless guiding-center code, it is shown that, for two investigated volumes in bulk plasma, some regions phase space are correlated and magnetic configuration has little influence this correlation. For FIDA system, between these explained well by configuration. Sightlines measurement at same spatial locations have highest...
Abstract In this paper, we present an analysis of the conservation currents in a full-F electromagnetic gyro-kinetic model long-wavelength limit. This equation corresponds to what is usually called ‘vorticity equation’, which not strictly correct as it cannot be formulated curl velocity equation. will therefore use term ‘current equation’ instead. Our results are relevant reduced plasma descriptions like gyro-kinetic, drift-kinetic, gyro-fluid and drift-fluid models for tokamaks...