A5048706071- Dust and Plasma Wave Phenomena
- Cold Atom Physics and Bose-Einstein Condensates
- Ionosphere and magnetosphere dynamics
- Semiconductor Quantum Structures and Devices
- High-pressure geophysics and materials
- Quantum and electron transport phenomena
- Atomic and Molecular Physics
- Advanced Chemical Physics Studies
- Magnetic confinement fusion research
- Mass Spectrometry Techniques and Applications
- Quantum, superfluid, helium dynamics
- Magnetic properties of thin films
- Mechanical and Optical Resonators
- Plasma Diagnostics and Applications
- Solid-state spectroscopy and crystallography
- Phase-change materials and chalcogenides
- Advanced Semiconductor Detectors and Materials
- Earthquake Detection and Analysis
- Organic and Molecular Conductors Research
- Laser-induced spectroscopy and plasma
- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
- Physics of Superconductivity and Magnetism
- Solar and Space Plasma Dynamics
- Superconducting and THz Device Technology
Kiel University
2014-2024
Interface (United States)
2024
Boston College
2013-2015
Heinrich Heine University Düsseldorf
2012
University of Kansas
2007
Ludwig Boltzmann Institute for Age Research
1969-2005
Ruhr University Bochum
1980-1985
University of Vienna
1969-1981
Ludwig Boltzmann Institute for Digital Health and Prevention
1969-1978
University of North Texas
1977-1978
Warm dense matter (WDM) -- an exotic state of highly compressed has attracted high interest in recent years astrophysics and for laboratory systems. At the same time, this is extremely difficult to treat theoretically. This due simultaneous appearance quantum degeneracy, Coulomb correlations thermal effects, as well overlap plasma condensed phases. Recent breakthroughs are successful application density functional theory (DFT) methods which, however, often lack necessary accuracy predictive...
The dependence of the mobility $n$-InAs on temperature and electric field was measured between 4.2 30 K 0.05 10 V/cm, respectively. Furthermore, variation nonoscillatory as well oscillatory part magnetoresistance (Shubnikov-de Haas effect) with applied studied experimentally. It found that decrease amplitudes Shubnikov-de (SdH) effect depends time after application allows a direct time-resolved observation increasing electron temperature. non-Ohmic transport is interpreted aid an...
The theoretical description of complex (dusty) plasmas requires multiscale concepts that adequately incorporate the correlated interplay streaming electrons and ions, neutrals dust grains. Knowing effective dust–dust interaction, problem can be effectively reduced to a one-component plasma model subsystem. goal this paper is systematic evaluation electrostatic potential distribution around grain in presence environment by means two complementary approaches: (i) high-precision computation...
Comparative studies of capacitively coupled radio-frequency discharges in helium and argon at pressures between 10 80 Pa are presented applying two different fluid modelling approaches as well independently developed particle-in-cell/Monte Carlo collision (PIC/MCC) codes. The focus is on the analysis range applicability a recently proposed model including an improved drift-diffusion approximation for electron component its comparison with results using classical benchmark obtained by PIC/MCC...
The structural properties of strongly coupled ions in dense plasmas with moderately to degenerate electrons are investigated the framework one-component plasma model interacting through a screened pair interaction potential. Special focus is put on description electronic screening Singwi-Tosi-Land-Sjölander (STLS) approximation. Different cross-checks and analyses using ion potentials obtained from ground-state quantum Monte Carlo data, random phase approximation (RPA), existing analytical...
Abstract The study of matter under extreme densities and temperatures as they occur, for example, in astrophysical objects nuclear fusion applications has emerged one the most active frontiers physics, material science, related disciplines. In this context, a key quantity is given by dynamic structure factor S ( q , ω ), which probed scattering experiments—the widely used method diagnostics at these conditions. addition to its importance warm dense matter, modelling such properties...
Accurate knowledge of the properties hydrogen at high compression is crucial for astrophysics (e.g., planetary and stellar interiors, brown dwarfs, atmosphere compact stars) laboratory experiments, including inertial confinement fusion. There exists experimental data equation state, conductivity, Thomson scattering spectra. However, analysis measurements extreme pressures temperatures typically involves additional model assumptions, which makes it difficult to assess accuracy rigorously. On...
Adopting the Kane model of nonparabolic conduction band InSb, calculations energy-loss rates electrons to acoustic modes via deformation potential and piezoelectric coupling polar optical are performed. Use is made matrix elements which take into account $p$-function admixture static screening electron-phonon interaction. The applicability this theoretical approach experiments at 4.2 K in strongly degenerate $n\ensuremath{-}\mathrm{I}\mathrm{n}\mathrm{S}\mathrm{b}$ examined. Measurements...
We propose and demonstrate a concept that mimics the magnetization of heavy dust particles in complex plasma while leaving properties light species practically unaffected. It makes use frictional coupling between neutral gas, which allows to transfer angular momentum from rotating gas column well-controlled rotation cloud. This induces Coriolis force acts exactly as Lorentz magnetic field. Experimental normal mode measurements for small cluster with four show excellent agreement theoretical...
The dynamical structure factor (DSF) of strongly coupled ions in dense plasmas with partially and degenerate electrons is investigated. main focus on the impact electronic correlations (nonideality) ionic DSF. latter computed by carrying out molecular dynamics (MD) simulations a screened ion-ion interaction potential. screening taken into account invoking Singwi-Tosi-Land-Sj\"olander approximation, it compared to MD simulation data obtained considering random phase approximation using Yukawa...
A rotating dusty plasma apparatus was constructed to provide the possibility of experimental emulation extremely high magnetic fields by means Coriolis force, observable in a corotating measurement frame. We present collective excitation spectra for different rotation rates with induction equivalent up 3200 T. identify onset magnetoplasmon-equivalent mode dispersion macroscopic two-dimensional single-layer plasma. The results are supported molecular dynamics simulations 2D magnetized Yukawa systems.
Laser manipulation allows to control the kinetic particle temperature in dusty plasmas. Different methods of laser heating for plasma crystals are benchmarked experimentally. The analyzed with respect homogeneity and isotropy a spatial, temporal, statistical sense. It is shown that it possible achieve dynamics very close thermal equilibrium allow detailed study phase transitions finite size systems.
The self-diffusion phenomenon in a two-dimensional dusty plasma at extremely strong (effective) magnetic fields is studied experimentally and by means of molecular dynamics simulations. In the experiment high field introduced rotating particle cloud observing trajectories corotating frame, which allows reaching effective up to 3000 T. experimental results confirm predictions simulations: (i) superdiffusive behavior found intermediate timescales (ii) dependence coefficient on well reproduced.
The existence of plasma oscillations at multiples the magnetoplasmon frequency in a strongly coupled two-dimensional magnetized Yukawa is reported, based on extensive molecular dynamics simulations. These modes are analogues Bernstein which renormalized by strong interparticle correlations. Their properties theoretically explained dielectric function incorporating combined effect magnetic field, correlations and finite temperature.
Strongly coupled plasmas in which the interaction energy exceeds kinetic play an important role many astrophysical and laboratory systems including compact stars, laser dusty plasmas. They exhibit unusual collective properties, such as liquid or crystalline behaviour, peculiar oscillation spectra transport properties. Recently, strongly were studied presence of a strong magnetic field by computer simulations, modifications their properties observed. While magnetization is common stellar it...
The electrostatic potential of a moving dust grain in complex plasma with magnetized ions is computed using linear response theory, thereby extending our previous work for unmagnetized plasmas [P. Ludwig et al., New J. Phys. 14, 053016 (2012)]. In addition to the magnetic field, approach accounts finite ion temperature as well ion-neutral collisions. Our recently introduced code \texttt{Kielstream} used an efficient calculation potential. Increasing magnetization ions, we find that shape...
Abstract The effect of an electric field on the amplitudes Shubnikov‐de Haas (SdH) oscillations Te‐doped n‐type gallium antimonide has been studied in samples with Fermi energies well below 〈111〉 satellite minima. Therefore transport effects were due to carriers Γ 1 ‐minimum alone. From decrease SdH‐amplitudes variation electron temperature up 15 V/cm calculated. measured energy loss rate electrons lattice is compared calculated values assuming scattering by acoustic phonons. With a...
Dust dynamics simulations utilizing a dynamical screening approach are performed to study the effect of ion-streaming on self-organized structures in three-dimensional spherically confined complex (dusty) plasma. Varying Mach number M, ratio ion drift velocity sound velocity, reproduce experimentally observed cluster configurations two limiting cases: at M = 0 strongly correlated crystalline consisting nested spherical shells (Yukawa balls) and, for ⩾ 1, flow-aligned dust chains,...
A first-principle study of the collective oscillation spectrum a strongly correlated one-component plasma in strong magnetic field is presented. The consists six fundamental modes which are found to be good agreement with results from Quasi-Localized Charge approximation. At high frequencies additional observed that include Bernstein-type oscillations and their transverse counterparts importance for high-frequency optical transport properties these plasmas.
The influence of non-Maxwellian ions on the ion-dust streaming instability in a complex plasma is investigated. ion susceptibility employed for calculations self-consistently accounts acceleration by homogeneous background electric field and their collisions with neutral gas particles via Bhatnagar-Gross-Krook collision term [e.g., A. V. Ivlev et al., Phys. Rev. E 71, 016405 (2005)], leading to significant deviations from shifted Maxwellian distribution. dispersion relation properties most...
The composition of a primary Ar2+ ion beam is analysed with respect to 3P, 1D and 1S states by aid the translational attenuation method (TAM). corresponding fractions are found be 0.48, 0.37 0.15, respectively. Measurements show that electron capture slow ions depend sensitively on initial projectile state population. Whereas in Ne target Ar2+(3P) give main contribution reaction, He metastable 1D2 more effective factor about 19. Finally, krypton spectrum dominated reactions Ar2+(1S0).
Abstract Spherical crystals continue to attract increasing interest in many fields, including trapped ions and dusty plasmas. These strongly coupled systems are excellent objects study fundamental interactions interesting correlation phenomena while they relatively easy realize observe. Experiments simulations show a spherical arrangement nested shells. This work discusses new experimental simulation results for small ( N ≤ 54) as well the influence of temperature charge fluctuations on...
The correlation buildup and the formation dynamics of shell structure in a spherically confined one-component plasma are studied. Using Langevin simulations relaxation processes characteristic time scales their dependence on pair interaction dissipation investigated. While systems with Coulomb (e.g., trapped ions) harmonic confinement starts at edge proceeds inward, this trend is significantly weakened for dusty plasmas Yukawa interaction. With suitable change conditions crystallization...
Two different approaches to the calculation of wave spectra magnetized strongly coupled liquid one-component plasmas are analzyed: semianalytical quasilocalized charge approximation (QLCA) and angle-averaged harmonic lattice (AAHL) theory. Both theories benchmarked against numerical evidence obtained from molecular dynamics simulations. It is found that not too far melting transition ($\ensuremath{\Gamma}\ensuremath{\gtrsim}100$), AAHL theory superior QLCA, while further away transition,...