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Equilibrium properties of hydrogen-helium mixtures under thermodynamic conditions found in the interior of giant gas planets are studied by means of density functional theory molecular dynamics simulations. Special emphasis is placed on the…

Materials Science · Physics 2009-09-29 Jan Vorberger , Isaac Tamblyn , Stanimir A. Bonev , Burkhard Militzer

The observation is presented of naturally occurring pairing of particles and their cooperative drift in a two-dimensional plasma crystal. A single layer of plastic microspheres was suspended in the plasma sheath of a capacitively coupled rf…

Plasma Physics · Physics 2015-06-16 S. K. Zhdanov , L. Couëdel , V. Nosenko , H. M. Thomas , G. E. Morfill

Micro hollow cathode discharges (MHCD) were produced using 250 m thick dielectric layer of alumina sandwiched between two nickel electrodes of 8 m thickness. A through cavity at the center of the chip was formed by laser drilling technique.…

This short article describes flow parameters, numerical method, and animations of the fluid dynamics video "LES of an Inclined Jet into a Supersonic Turbulent Crossflow"…

Structure and lattice dynamics of the (001) surface of Sr$_2$CuO$_2$Cl$_2$ have been studied by helium atom scattering (HAS). Analysis of diffraction patterns obtained by elastic HAS revealed a surface periodicity consistent with bulk…

Other Condensed Matter · Physics 2009-11-11 M. Farzaneh , XF. Liu , M. El-Batanouny , F. C. Chou

Helium atom scattering (HAS) studies of the H-covered Mo(110) and W(110) surfaces reveal a twofold anomaly in the respective dispersion curves. In order to explain this unusual behavior we performed density functional theory calculations of…

mtrl-th · Physics 2009-10-30 Bernd Kohler , Paolo Ruggerone , Matthias Scheffler

We report the controlled injection of near-isolated micron-sized liquid droplets into a low temperature He-Ne steady-state rf plasma at atmospheric pressure. The H2O droplet stream is constrained within a 2 mm diameter quartz tube. Imaging…

In this manuscript, a fluid model is utilized to calculate the density of plasma species assuming geometrically symmetric Ar/CF4 Radiofrequency Capacitively Coupled Plasmas. The electrodes are driven by a sinusoidal waefront with an…

Plasma Physics · Physics 2023-03-28 M. G. Elsheikh , Y. Abdella , T. El-Ashram , W. M. Moslem , M. Shihab

A two-dimensional dust crystal levitated in the sheath of a modified Gaseous Electronics Conference (GEC) reference cell is manipulated by heating or cooling the lower electrode. The dust charge is obtained from top-view pictures of the…

Plasma Physics · Physics 2010-10-20 Victor Land , Bernard Smith , Lorin Matthews , Truell Hyde

Helium (He) is the ideal atom to perform tests of ab-initio calculations in two-electron systems that consider all known effects, including quantum-electrodynamics and nuclear-size contributions. Recent state-of-the-art calculations and…

Atomic Physics · Physics 2025-01-07 Gloria Clausen , Kai Gamlin , Josef A. Agner , Hansjürg Schmutz , Frédéric Merkt

Resonant scattering of He I 1.0833$\mu$m triplet photons by metastable He 2 $^3$S$_1$ is studied for optical depths characteristic of H II regions. Regions with large He 2 $^3$S$_1$ column densities are predicted to have unusually broad,…

Astrophysics of Galaxies · Physics 2026-01-23 B. T. Draine

We examine the conditions of the plasma along a sample of 'classical' Herbig-Haro jets located in the Orion and Vela star forming regions, through combined optical-infrared spectral diagnostics. Our sample includes HH 111, HH 34, HH 83, HH…

The low density hydrogen and helium in the IGM probed by QSO absorption lines is sensitive to the amplitude and spectral shape of the metagalactic UV background. We use realistic HI and HeII Ly-alpha forest spectra, constructed from…

Astrophysics · Physics 2009-11-13 James S. Bolton , Martin G. Haehnelt , Matteo Viel , Robert F. Carswell

The 2D flow of a foam confined in a Hele-Shaw cell through a contraction is investigated. Its rheological features are quantified using image analysis, with measurements of the elastic stress, rate of plasticity, and velocity. The behavior…

Soft Condensed Matter · Physics 2015-05-13 Benjamin Dollet

The ionization rate of interstellar material by cosmic rays has been a major source of controversy, with different estimates varying by three orders of magnitude. Observational constraints of this rate have all depended on analyzing the…

Solar and Stellar Astrophysics · Physics 2015-05-14 Nick Indriolo , L. M. Hobbs , K. H. Hinkle , Benjamin J. McCall

Using X-ray micro-diffraction and surface acoustic wave spectroscopy, we measure lattice swelling and elastic modulus changes in a W-1%Re alloy after implantation with 3110 appm of helium. A fraction of a percent observed lattice expansion…

This article presents a new experiment aiming at BEC of metastable helium atoms. It describes the design of a high flux discharge source of atoms and a robust laser system using a DBR diode coupled with a high power Yb doped fiber amplifier…

Collisions of metastable antiprotonic helium with medium atoms induce transitions between hyperfine structure sublevels as well as shift and broadening of the microwave M1 spectral lines. We consider these effects in the framework of a…

Nuclear Theory · Physics 2009-11-10 G. Ya. Korenman , N. P. Yudin , S. N. Yudin

Electrons on the liquid helium surface form an extremely clean two dimensional system where different plasmon-excitations can coexist. Under a magnetic field time reversal symmetry is broken and all the bulk magneto-plasmons become gaped at…

Mesoscale and Nanoscale Physics · Physics 2021-02-17 A. D. Chepelianskii , D. Papoular , H. Bouchiat , K. Kono

The relaxation of photoexcited nanosystems is a fundamental process of light-matter interaction. Depending on the couplings of the internal degrees of freedom, relaxation can be ultrafast, converting electronic energy in a few fs, or slow,…