A5013517024- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Fusion materials and technologies
- Pulsed Power Technology Applications
- Superconducting Materials and Applications
- Nuclear Physics and Applications
- Image and Signal Denoising Methods
- Ultrasonics and Acoustic Wave Propagation
- Seismic Imaging and Inversion Techniques
- Solar and Space Plasma Dynamics
- Microwave Engineering and Waveguides
- Gyrotron and Vacuum Electronics Research
- Underwater Acoustics Research
- Astro and Planetary Science
- Electromagnetic Launch and Propulsion Technology
- Geophysical Methods and Applications
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Seismic Waves and Analysis
- Nuclear reactor physics and engineering
- Transportation Systems and Safety
- Power Transformer Diagnostics and Insulation
- Electromagnetic Compatibility and Measurements
- Electrostatic Discharge in Electronics
Swedish Defence Research Agency
2023-2025
KTH Royal Institute of Technology
2017-2024
Uppsala University
2018
Alfvén waves are electromagnetic perturbations inherent to magnetized plasmas that can be driven unstable by a free energy associated with gradients in the energetic particles' distribution function. The particles velocities comparable velocity may excite instabilities via resonant wave–particle and momentum exchange. Burning large population of fusion born super-Alfvénic alpha magnetically confined devices prone weakly-damped eigenmodes (AEs) that, if allowed grow unabated, cause...
Ion cyclotron resonance heating is a versatile method that has been demonstrated to be able efficiently couple power directly the ions via fast magnetosonic wave. However, at temperatures relevant for reactor grade devices such as DEMO, electron damping becomes increasingly important. To reduce damping, it possible use an antenna with spectrum dominated by low parallel wavenumbers. Moreover, using unidirectional spectrum, travelling wave array antenna, wavenumber can downshifted mounting in...
In DT plasmas, toroidal Alfvén eigenmodes (TAEs) can be made unstable by the alpha particles resulting from fusion reactions, and may induce a significant redistribution of fast ions. Recent experiments have been conducted in JET deuterium plasmas order to prepare scenarios aimed at observing alpha-driven TAEs future campaign. Discharges low density, large core temperatures associated with presence internal transport barriers characterised good energetic ion confinement performed. ICRH has...
During the 2015-2016 JET campaigns many efforts have been devoted to exploration of high-performance plasma scenarios envisaged for DT operation in JET.In this paper we review various key recent hybrid discharges and model combined ICRF+NBI heating.These deuterium with beams had ICRF antenna frequency tuned match cyclotron minority H at centre tokamak coinciding second harmonic resonance D. The modelling takes into account synergy between NBI heating through D beam ions which allows us...
Dedicated studies performed for toroidal Alfvén eigenmodes (TAEs) in ASDEX-Upgrade (AUG) discharges with monotonic q-profiles have shown that electron cyclotron resonance heating (ECRH) can make TAEs more unstable. In these AUG discharges, energetic ions driving were obtained by ion (ICRH). It was found off-axis ECRH facilitated TAE instability, appearing and disappearing on timescales of a few milliseconds when the power switched off. On-axis had much weaker effect TAEs, co- counter-current...
Abstract The current response of a hot magnetized plasma to radio-frequency wave is non-local, turning the electromagnetic equation into an integro-differential equation. Non-local physics gives rise and absorption processes not observed in local media. Furthermore, non-local alters propagation properties plasma. In this work, iterative method that accounts for parallel effects 2D axisymmetric tokamak plasmas developed, implemented, verified. based on finite element Fourier decomposition,...
Abstract In this work, we use reduced and perturbative models to examine the stability of toroidal Alfvén eigenmodes (TAEs) during internal transport barrier (ITB) afterglow in JET experiments designed for observation alpha driven TAEs. We demonstrate that JET-like conditions, it is sufficient an incompressible cold plasma model TAE reproduce experimental adiabatic features such as frequency position. When ion cyclotron resonant heating (ICRH) used destabilize TAEs, core-localised modes are...
Two ion cyclotron resonance heating (ICRH) systems are planned for ITER, each system containing 24 antennas distributed as a two by four array of poloidal triplets. The ITER designed to operate at phase difference between the upper and lower triplet in antenna currents. Since current tokamak experiments normally , experience from ICRH schemes with is lacking. In this paper, effects phasing on power absorption coupling studied using novel code FEMIC, which described here. Simulations JET...
Abstract This paper outlines the results of particle-in-cell simulations a relativistic magnetron with six cavities and transparent cathode configuration. Excitation π mode in interaction region was attained, which turn led to $\textrm{TE}_{11}$ emission microwaves waveguide. transformation achieved non-symmetric diffraction output, consisting four large two small tapered cavities. Simulations were performed voltage across anode-cathode gap varying from 164 356 kV, axial magnetic field...
Modeling of Ion Cyclotron Resonance Heating (ICRH) is difficult because spatial dispersion. Numerical methods based on finite element or difference have difficulties in handling dispersive effects, the response non-local. Fourier spectral can handle dispersion, however, these complex geometries outside plasma domain and tend to produce dense matrices that are time consuming invert.
The wave equation for a spatially dispersive inhomogeneous magnetized plasma is given by an integro-differential equation. effects caused spatial dispersion in the directions perpendicular and parallel to magnetic field are quite different. In this study, we show how solve using newly developed iterative wavelet spectral method two cases. first case, applied propagating kinetic Alfvén direction solved all orders FLR. To conserve energy flux, order corrections equilibrium gradients used...
A novel method for solving wave equations with spatial dispersion is presented, suitable applications to ion cyclotron resonance heating. The splits the operator into a dispersive and non-dispersive part. latter can be inverted e.g. finite element methods. evaluated using wavelet representation of dielectric kernel added by means iteration. has been successfully tested on low frequency kinetic Alfven second order Larmor radius effects in nonuniform plasma slab.
Modelling the propagation and dissipation of RF waves in ion cyclotron range frequencies is challenging due to presence spatial dispersion.In this work, we are presenting an iterative scheme that includes dispersive effects all tensor elements 2D axisymmetry.The proposed method implemented existing full wave solver FEMIC applied two fast heating scenarios, one with ITER-like plasma other AUG-like plasma, order evaluate importance parallel dispersion different cases.It was found marginal ITER...
Abstract Modeling the propagation and damping of electromagnetic waves in a hot magnetized plasma is difficult due to spatial dispersion. In such media, dielectric response becomes non-local wave equation an integro-differential equation. application RF heating current drive tokamak plasmas, finite Larmor radius (FLR) causes dispersion, which gives rise physical phenomena as higher harmonic ion cyclotron mode conversion electrostatic waves. this paper, new numerical method based on iterative...
A method for calculating the wave field spatial dispersive media is proposed suitable FEM. The based on operator splitting by separating induced current and calculations, solving system means of iterations. In order to take into account several coexisting waves with different poloidal mode numbers when decomposed wavelets, which calculated assuming plasma be weakly non-uniform.
A relativistic magnetron with a novel diffraction output has been analyzed 3D particle-in-cell simulations. Using six-cavity cylindrical cathode, the generated microwaves are propagated through tapered four radially opposite cavities, to produce TE11-mode in waveguide at output. The performance evaluated for different input coaxial line radii, voltages ranging from 185 kV 330 anode-cathode gap and applied magnetic fields by Helmholtz pair 0.26 T 0.32 T. Results show successful efficient TE11...
The increasing threat from high power electromagnetic weapons necessitates further research in pulsed level testing order to accurately assess the potential damage it can cause. This study is part of an ongoing collaboration where a reference test setup has previously been developed facilitate exchange results between different laboratories. purpose examine tests that have conducted reverberation chamber with time constants for pulse widths 600 ns. We find there some discrepancy two...