A5068719066- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Solar and Space Plasma Dynamics
- Fluid Dynamics and Turbulent Flows
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Spectroscopy and Laser Applications
- Atmospheric Ozone and Climate
- Nuclear reactor physics and engineering
- Fluid Dynamics and Vibration Analysis
- Geomagnetism and Paleomagnetism Studies
- Particle Dynamics in Fluid Flows
- Wind and Air Flow Studies
- Meteorological Phenomena and Simulations
- High-Energy Particle Collisions Research
- Nuclear Physics and Applications
- Inorganic Fluorides and Related Compounds
- Molecular Spectroscopy and Structure
- Scientific Research and Discoveries
- Physics of Superconductivity and Magnetism
- Oceanographic and Atmospheric Processes
- Geological formations and processes
Technical University of Denmark
2016-2025
Royal Military Academy
2020
Plasma Technology (United States)
2007-2018
Fusion Academy
2013-2018
Culham Science Centre
2018
Max Planck Society
2015
Max Planck Institute for Plasma Physics
2015
European Environment Agency
2013
Nordic Laboratory for Luminescence Dating
1994-2012
Centre for Sustainable Energy
1995-2011
By means of an infrared prism-grating spectrometer equipped with a multiple-path cell, seventeen vibration-rotation absorption bands SO2 have been observed and recorded. Seven exhibiting rotational structure were analyzed for the constants upper lower vibrational states. Harmonic anharmonic in energy expression calculated, suitable values force four-constant potential function obtained. No ascribable to S34O216 found.
Fluctuations and particle transport in the scrape-off layer of TCV plasmas have been investigated by probe measurements direct comparison with two-dimensional interchange turbulence simulations at outer midplane. The experiments demonstrate that increasing line-averaged core plasma density, radial density profile scale length becomes broader. flux statistics far exhibit a high degree statistical similarity respect to changes density. onto main chamber wall midplane scales linearly local...
This paper combines earlier preliminary reports on F2CO, FClCO and Cl2CO into a complete report the Raman infrared spectra of these molecules. Details measurement handling samples are given. The fundamental frequencies observed in both effect (liquid) (gas) large number overtone combination have been identified collected tables. band envelopes described compared with predicted basis molecular models. Resonance between ν2 2ν1 F2CO ν1+ν4 is discussed.
An electrostatic coherent mode near the electron diamagnetic frequency (20-90 kHz) is observed in steep-gradient pedestal region of long pulse H-mode plasmas Experimental Advanced Superconducting Tokamak, using a newly developed dual gas-puff-imaging system and diamond-coated reciprocating probes. The propagates direction plasma frame with poloidal wavelength ∼8 cm. drives significant outflow particles heat as measured directly probes, thus greatly facilitating sustainment. This shows nature...
The infrared and Raman spectra of SiF4 have been completely reexamined extended. spectrum yields four lines at 268 cm−1, 390 800 1010 which assigned ν2, ν4, ν1, ν3 respectively. In the measurements, both prism grating spectrometers were utilized. Several bands reported in earlier work ascribed to impurities nine new observed identified. long-wave ν4 391 cm−1 has with a KRS−5 its envelope determined. Bands involving appear PR spacing about 12 while those 20 cm−1.
Two-dimensional fluid simulations of interchange turbulence for geometry and parameters relevant the scrape-off layer magnetized plasmas are presented. The computations, which have distinct plasma production loss regions, reveal bursty ejection particles heat from bulk in form blobs. These structures propagate far into where they dissipated due to transport along open magnetic field lines. From single-point recordings it is shown that blobs asymmetric conditional wave forms lead positively...
Probe measurements of electrostatic plasma fluctuations in the scrape-off layer (SOL) TCV tokamak are compared with results from two-dimensional interchange turbulence simulations. Excellent agreement is found for both radial variation statistical moments and temporal correlations, clearly indicating that turbulent transport SOL due to advection blob-like filamentary structures. This offers an explanation basic mechanism driving anomalous particle now commonly observed broad density...
The first experimental evidence showing the connection between blob/hole formation and zonal-flow generation was obtained in edge plasma of JET tokamak. Holes as well blobs are observed to be born shear layer, where zonal-flows off meso-scale coherent structures, leading disconnection positive negative pressure perturbations. newly formed transport azimuthal momentum up gradient flow drive while moving outwards. During this process energy is transferred from structures zonal flows via...
The spectrometer and experimental methods described in a companion paper were used to measure the center frequencies of some absorption lines HF fundamental first-overtone bands pressure-broadened shapes fundamental. centers both calculated, strongly J-dependent, pressure-induced line shifts measured for A method correcting shape spectral effects instrumental broadening order obtain "true shape" is explained. It was possible true whose pressure broadened half-width as small (0.03 cm−1)...
This paper is a report of the complete investigation and interpretation Raman infrared spectra MoF6, WF6, UF6. The photographs MoF6 WF6 exhibit three intense lines in accord with earlier measurements on UF6 solution. exploration from 2–40μ yielded great many bands for each molecule. Two these were quite case identified as fundamentals while remaining weaker ones overtones combinations. spectrum was repeated 2–17μ substantially same results work. Extension this 17–40μ made new discovered....
The infrared spectrum of CF4 has been remeasured from 2–19μ and extended to about 33μ, the GeF4 observed 2–38μ. Through use purer samples more gas than in previous investigations, a large number new overtones combination bands were CF4, several eliminated as impurities. Identifications these are given. infrared-inactive ν2 was observed, probably because interaction with ν4, at 435 cm−1 agreement Raman line 437 cm−1. In two active fundamentals ν3 ν4 800 260 cm−1, respectively. Eight overtone...
This paper presents simulations of isolated 3D filaments in a slab geometry obtained using newly developed reduced fluid code, written the BOUT++ framework. First, systematic scans were performed to investigate how dynamics filament are affected by its amplitude, perpendicular size, and parallel extent. The size was found have strong influence on motions, as it determined relative importance currents polarization viscous currents, whilst drift-wave instabilities observed if initial amplitude...
A detailed cross-device investigation on the role of filamentary dynamics in high-density regimes has been performed within EUROfusion framework, comparing ASDEX Upgrade (AUG) and TCV tokamaks. Both devices run density ramp experiments at different levels plasma current, keeping toroidal field or q95 constant order to disentangle parallel connection length current. During scan a field, both scrape-off layer (SOL) profiles tend develop clear SOL shoulder lower edge whenever current is...
We report observations of nonlinear two-plasmon decay instabilities (TPDIs) a high-power microwave beam, process similar to half-harmonic generation in optics, during electron cyclotron resonance heating tokamak. TPDIs are found occur regularly the plasma edge due wave trapping density fluctuations for various confinement modes, and frequencies both observed daughter waves agree with modeling. Emissions from cascade subsequent decays, which indicate ion Bernstein waves, correlated fast-ion...
Numerical fluid simulations of interchange turbulence for geometry and parameters relevant to the boundary region magnetically confined plasmas are shown result in intermittent transport qualitatively similar recent experimental measurements. The two-dimensional simulation domain features a forcing with spatially localized sources particles heat outside which losses due motion along open magnetic-field lines dominate, corresponding edge scrape-off layer, respectively. Turbulent states reveal...
Large-scale radial advection of isolated structures in nonuniformly magnetized plasmas is investigated. The underlying mechanism considered due to the nonlinear evolution interchange motions, without any presumption plasma sheaths. Theoretical arguments supported by numerical simulations reveal an inertial scaling for velocity ideal limit. This increases as square root structure size relative length scale magnetic field. magnitude velocity, well dynamical structures, compares favorably with...
Low-frequency, flute-type electrostatic fluctuations propagating across a strong, homogeneous magnetic field are studied experimentally. The generated by the Kelvin–Helmholtz instability. presence of relatively long-lived vortexlike structures in background wide-band turbulent is demonstrated conditional sampling technique. Depending on plasma parameters, dominant can appear as monopole or multipole vortices, dipole vortices particular. importance large for diffusion discussed. A statistical...
First principles expressions are given for the parameters governing collisional diffusion and parallel losses of mass, momentum energy in tokamak scrape-off layer (SOL) plasmas. These dissipative, or damping, coefficients based on neoclassical perpendicular transport (Pfirsch-Schluter diffusion) classical (sub-sonic advection Spitzer-Harm diffusion). When numerical values derived from these used to compute damping edge-SOL electrostatic (ESEL) turbulence code, simulations correctly reproduce...
Results are presented from probe measurements in the low field side scrape-off layer (SOL) region of TCV during plasma current scan experiments. It is shown that with decreasing radial particle density profile becomes broader and fluctuation levels turbulence driven flux increase. In far SOL fluctuations exhibit a high degree statistical similarity at wall radius scale inversely current. Together previous experiments, this indicates transport increase collisionality. Such collisionality...
The low temperature boundary layer plasma (scrape-off or SOL) between the hot core and surrounding vessel determines level of power loading, erosion implantation material surfaces, thus viability tokamak-based fusion as an energy source. This study explores mechanisms affecting formation flattened density profiles, so-called 'density shoulders', in low-field side (LFS) SOL, which modify ion neutral fluxes to surfaces—and subsequent erosion. There is evidence against local enhancement...
The prism spectrum of NOF is reported from 2–38μ. Twelve absorption bands were observed and identified in terms the fundamental frequencies ν1(N–O)=1844.03 cm−1, ν2(bending)=521 ν1(N–F)=765.85 cm−1. Comparison with companion molecules NOCl NOBr made.
The infrared vibration-rotation spectrum of HF has been re-examined out through J=11 for the fundamental, and J=8 first overtone. Five lines pure rotational (J=10, 11, 12, 14, 15) have observed in absorption emission between 15 24 μ. Extension measurement to larger J values makes it possible observe effect term HvJ3(J+1)3 energy, obtain Hv. With new data molecular constants re-evaluated by IBM machine. These when used with energy expression permit accurate prediction levels.
Abstract We present an overview of results from a series L–H transition experiments undertaken at JET since the installation ITER-like-wall (JET-ILW), with beryllium wall tiles and tungsten divertor. Tritium, helium deuterium plasmas have been investigated. Initial in tritium show ohmic transitions low density power threshold for ( P LH ) is lower than ones densities, while we still lack contrasted data to provide scaling high densities. In there notable shift which minimum <?CDATA...