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In situ low-energy electron microscopy was used to study interlayer mass transport kinetics during annealing of three-dimensional (3D) TiN(111) mounds, consisting of stacked 2D islands, at temperatures T between 1550 and 1700 K. At each T,…

Materials Science · Physics 2009-11-10 S. Kodambaka , Navot Israeli , J. Bareno , W. Swiech , Kenji Ohmori , I. Petrov , J. E. Greene

We characterise the thermal state of the intergalactic medium (IGM) in ten redshift bins in the redshift range $2 \leq z \leq 4$ with a sample of 103 high resolution, high S/N Ly$\alpha$ forest spectra using four different flux distribution…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-20 Prakash Gaikwad , Raghunathan Srianand , Martin G. Haehnelt , Tirthankar Roy Choudhury

We combine UV spectra obtained with the HST/GHRS echelle, IMAPS, and Copernicus to study the abundances and physical conditions in the predominantly ionized gas seen at high (-105 to -65 km/s) and intermediate velocities (-60 to -10 km/s)…

Astrophysics · Physics 2008-11-26 D. E. Welty , E. B. Jenkins , J. C. Raymond , C. Mallouris , D. G. York

The measurement of the electron energy distribution (EED) of electrons escaping axially from a minimum-B electron cyclotron resonance ion source (ECRIS) is reported. The experimental data were recorded with a room-temperature 14 GHz ECRIS…

Electron heating and ionization dynamics in capacitively coupled radio frequency (RF) atmospheric pressure microplasmas operated in helium are investigated by Particle in Cell simulations and semi-analytical modeling. A strong heating of…

Plasma Physics · Physics 2013-06-03 T. Hemke , D. Eremin , T. Mussenbrock , A. Derzsi , Z. Donkó , K. Dittmann , J. Meichsner , J. Schulze

We present a new measurement of the energy spectrum of iron nuclei in cosmic rays from 20 to 500 TeV. The measurement makes use of a template-based analysis method, which, for the first time, is applied to the energy reconstruction of…

A two-electron temperature plasma is produced by the method of diffusion of two different plasmas with distinct temperatures and densities. The method is simple and provides an adequate control over the plasma parameters. The study reveals…

Plasma Physics · Physics 2022-03-02 G. Sharma , K. Deka , R. Paul , S. Adhikari , R. Moulick , S. S. Kausik , B. K. Saikia

The hydrogen plasma is studied at temperatures T ~ 10^4 - 10^6 K using the free energy minimization method. A simple analytic free energy model is proposed which is accurate at densities up to 1 g/cc and yields convergent internal partition…

plasm-ph · Physics 2009-10-30 A. Y. Potekhin

Electron cooling as a method of creating intense ion beams has a practical upper limit when it comes to the peak phase space density of ion beams which can be achieved in practice. We describe a new experiment to study electron cooling of…

Accelerator Physics · Physics 2022-09-12 N. Banerjee , M. K. Bossard , J. Brandt , Y-K. Kim , B. Cathey , S. Nagaitsev , G. Stancari

The temperature of the low-density intergalactic medium is set by the balance between adiabatic cooling resulting from the expansion of the universe, and photo-heating by the UV-background. A sudden injection of entropy from the…

Astrophysics · Physics 2007-05-23 Tom Theuns , Saleem Zaroubi , Tae-Sun Kim

We characterise the performance of a surface-electrode ion "chip" trap fabricated using established semiconductor integrated circuit and micro-electro-mechanical-system (MEMS) microfabrication processes which are in principle scalable to…

Line ratio of O IV 1407.3 \AA/1401.1 \AA\- is calculated using mostly our own atomic and collisional data. Energy levels and oscillator strengths needed for this calculation have been calculated using a Hartree-Fock relativistic (HFR)…

Solar and Stellar Astrophysics · Physics 2015-06-17 Nabil Ben Nessib , Norah Alonizan , Rabia Qindeel , Sylvie Sahal-Bréchot , Milan S. Dimitrijević

The redshifted 21-cm signal from the epoch of reionization (EoR) directly probes the ionization and thermal states of the intergalactic medium during that period. In particular, the distribution of the ionized regions around the radiating…

We present a measurement of the low-energy (0--60$\,$keV) $\gamma$ ray spectrum produced in the $\alpha$-decay of $^{233}$U using a dedicated cryogenic magnetic micro-calorimeter. The energy resolution of $\sim$$10\,$eV, together with…

In the initial stages of ITER operation, ELM mitigation systems need to be commissioned. This requires controlled flat-top operation in type-I ELMy H-mode regimes. Hydrogen or helium plasma discharges are used exclusively in these stages to…

The fuelling of plasmas by shallow frozen pellets with simultaneous mitigation of edge localised modes (ELM) by external magnetic perturbation is demonstrated on the MAST tokamak. Post-pellet particle loss is dominated by ELMs and inter-ELM…

Plasma Physics · Physics 2015-10-29 M Valovic , L Garzotti , C Gurl , A Kirk , D Dunai , A R Field , I Lupelli , G Naylor , A Thornton

Time-resolved beam parameters measurement system can be achieve electron beam energy in LIA. In this paper introduce work principle and method of time-resolved beam parameters measurement system. Show the experiment layout of energy…

Accelerator Physics · Physics 2014-01-28 Yuan Wang

A new method is used to measure the physical conditions of the gas in damped Lyman-alpha systems (DLAs). Using high resolution absorption spectra of a sample of 80 DLAs, we are able to measure the ratio of the upper to lower fine-structure…

Astrophysics of Galaxies · Physics 2015-06-23 Marcel Neeleman , J. Xavier Prochaska , Arthur. M. Wolfe

We report on the experimental characterization of the RIT-2.5 radiofrequency ion thruster, complemented by particle-in-cell (PIC) simulations to establish correlations between plasma parameters and extracted beam properties. The thruster…

Accelerator Physics · Physics 2025-09-16 N. Joshi , O. Meusel

We compute robust lower limits on the spin temperature, $T_{\rm S}$, of the $z=8.4$ intergalactic medium (IGM), implied by the upper limits on the 21-cm power spectrum recently measured by PAPER-64. Unlike previous studies which used a…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-16 Bradley Greig , Andrei Mesinger , Jonathan C. Pober