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We have used a combination of pico-to-nano temporal/spatial scale computational physics and chemistry modeling of plasma–material interfaces in the tokamak fusion plasma edges to unravel the evolving characteristics, not readily accessible by empirical means, of lithium-, oxygen-, and hydrogen-containing materials of plasma-facing components under irradiation by hydrogen and its isotopes. In the present calculation, amorphous lithium compound surfaces containing oxygen, Li2O, and LiOH were irradiated by 1–100 eV particles at incident angles on the surface ranging from perpendicular to almost grazing angles. Consequential surface processes, reflection, retention, and sputtering were studied at "the same footing" and compared to earlier results from amorphous Li and LiH surfaces. The critical role of charging dynamics of lithium, oxygen, and hydrogen atoms in the surface chemistry during hydrogen-fuel irradiation was found to drive the kinetics and dynamics of these surfaces in unexpected ways that ultimately could have profound effects on fusion plasma confinement behavior and surface erosion. [ABSTRACT FROM AUTHOR]

Detailed experimental and computational information on the response of lithium surfaces to irradiation by slow hydrogenic particles (ions, atoms, molecules) is sparse and mainly speculative. In this work, we present a computational study of the reflection and retention of deuterium (D) atoms at crystalline and amorphous lithium surfaces at 300 and 500 K, where the D atoms have an impact energy in the range of 0.025–5 eV and incident angles of 0° (perpendicular incidence) or 85° (near-grazing incidence). Classical molecular dynamics simulations are performed with the reactive bond-order force field (ReaxFF) potentials. This study provides quantitative information on the deuterium sticking probability and recycling coefficient for lithium surfaces. Our results support the ongoing work at the Lithium Tokamak eXperiment-β fusion experiment as well as relevant experiments in the laboratory setting. [ABSTRACT FROM AUTHOR]

The effect of the Fe doping and the [110] poling on the optical and the photorefractive properties of the PZN-PT is investigated. The photorefractive properties were investigated by two-beam coupling experiments at a wavelength of 488 nm.

Pd/Mg3.3Ni films were prepared by dc sputtering deposition on three different substrates of glass, diamondlike carbon/Si, and Si. Hydrogenation and dehydrogenation cycles were performed on these samples simultaneously. The optical switching property due to the hydrogenation and dehydrogenation was monitored by the transmission of laser light via the glass substrate. The switching ability was totally lost after 120 cycles. We made comparative study of the composition change between the new (as-deposited) and old (after 120 switching cycles) samples by Rutherford backscattering (RBS), elastic recoil detection analysis (ERDA), and nuclear reaction analysis (NRA). From the RBS results we found out the segregation of a Mg layer between the Pd cap layer and the rest of the Mg–Ni layer. At the Pd/Mg interface in the old sample, thin MgO layer formed probably during the dehydrogenation process with O2. ERDA showed that there is much hydrogen in the old sample. NRA displayed the depth profiles of hydrogen distribution in the old sample. It is revealed that much hydrogen is accumulated at the interface between the Pd cap layer and the segregated Mg layer. It can be concluded that the formations of oxide and hydride of the segregated Mg layer are the main reasons for the degradation of the Mg3.3Ni switchable mirror. [ABSTRACT FROM AUTHOR]

The photorefractive properties of the iron-doped Pb(Zn1/3Nb2/3)O3-PbTiO3 (PZN-PT) relaxor ferroelectric single crystals were investigated by two-beam coupling experiments. The Fe:0.01 wt %- and the Fe:0.1 wt %-doped 0.91PZN-0.09PT single crystals were grown with the flux solution method. The Extinction spectrum, the electro-opric coefficient, the light-induced absorption change, and the photoconductivity were measured in these samples. The maximum gain coefficient reached to 21 cm-1, which is about twice as large as that of undoped PZN-PT. The grating formation rate decreases with the Fe concentration. [ABSTRACT FROM AUTHOR]

The photorefractive properties of the iron-doped Pb(Zn1/3Nb2/3)O3-PbTiO3 (PZN-PT) relaxor ferroelectric single crystals were investigated by two-beam coupling experiments. The Fe:0.01 wt %- and the Fe:0.1 wt %-doped 0.91PZN-0.09PT single crystals were grown with the flux solution method. The Extinction spectrum, the electro-opric coefficient, the light-induced absorption change, and the photoconductivity were measured in these samples. The maximum gain coefficient reached to 21 cm-1, which is about twice as large as that of undoped PZN-PT. The grating formation rate decreases with the Fe concentration. [ABSTRACT FROM AUTHOR]

An experimental study of the complicated u(sub i)-T curve produced by whitelight study or HeNe-laser-light illumination of thick films of YIG at 77 K is presented. It is suggested that there is photoinduced structural distortion around oxygen vacancies due to a photoinduced change of charge imbalance.

Presents a study which investigated the structural and magnetic properties of (R,Zr)(Fe,Co)[sub10](R=Nd,Sm) prepared by the rapid-quenching method. Influence of the presence of zirconium; Information on the saturation magnetization of crystals; Details of the magnetic hardening of the nitrogenated materials.

Recently, in Cs-seeded H− ion sources for fusion applications, the experiments have shown that the surface produced H− ions are mainly extracted from the bulk plasma region, that is, 1–2 cm inside from the beam aperture. The purpose of this paper is to clarify the extraction mechanism of the surface produced H− ions from the bulk plasma region in Cs-seeded H− ion sources for fusion applications by our 3-Dimensional Particle in Cell model for the vicinity of the beam aperture. In the present model, Coulomb collisions between surface produced H− ions and H+ ions (CC H−-H+) are taken into account by the Binary Collision Model. By our model, the trajectories of extracted surface produced H− ions and beam profiles have been investigated for the case with and without CC H−-H+. From the results of trajectories for extracted surface produced H− ions, it has been shown that the surface produced H− ions extracted from the bulk plasma region are drastically increased due to CC H−-H+. Thus, our results have shown that the surface produced H− ions are extracted from the bulk plasma region due to Coulomb collision with H+ ions. Moreover, our results of the beam profiles have shown that CC H−-H+ causes the increase in the beam convergence component. From these results, Coulomb collisions between surface produced H− ions and H+ ions are shown to be very important for the modeling of the extraction mechanism and for the beam optics in Cs-seeded H− ion sources for fusion applications. [ABSTRACT FROM AUTHOR]