Advanced mesoscale devices require tight tolerances of very fine features. Laser ablation is widely used for this purpose, and extreme-ultraviolet (EUV) lasers in particular allow for a tighter focus and lower-temperature machining than traditional lasers. The authors perform simulations and experiments of laser ablation using an EUV laser, producing high-aspect-ratio mesoscale (100 nm---1\textmu{}m) features with a high level of control over the ablation profile. This work provides an effective technique to investigate and promote capillary-discharge laser technology for industrial processes.
Abstract The JET 2019–2020 scientific and technological programme exploited the results of years of concerted scientific and engineering work, including the ITER-like wall (ILW: Be wall and W divertor) installed in 2010, improved diagnostic capabilities now fully available, a major neutral beam injection upgrade providing record power in 2019–2020, and tested the technical and procedural preparation for safe operation with tritium. Research along three complementary axes yielded a wealth of new results. Firstly, the JET plasma programme delivered scenarios suitable for high fusion power and alpha particle ( α ) physics in the coming D–T campaign (DTE2), with record sustained neutron rates, as well as plasmas for clarifying the impact of isotope mass on plasma core, edge and plasma-wall interactions, and for ITER pre-fusion power operation. The efficacy of the newly installed shattered pellet injector for mitigating disruption forces and runaway electrons was demonstrated. Secondly, research on the consequences of long-term exposure to JET-ILW plasma was completed, with emphasis on wall damage and fuel retention, and with analyses of wall materials and dust particles that will help validate assumptions and codes for design and operation of ITER and DEMO. Thirdly, the nuclear technology programme aiming to deliver maximum technological return from operations in D, T and D–T benefited from the highest D–D neutron yield in years, securing results for validating radiation transport and activation codes, and nuclear data for ITER.
The situations leading to the emergence of Moiré patterns in X-ray interferometers and the dependence of the period of these Moiré patterns on the wavelength and the order of reflection are investigated. The definite conditions of the emergence of Moiré patterns are elaborated. It is demonstrated, that not all the rotations of the reflecting planes and not all the differences in interplanar spacings in interferometers lead to the formation of Moiré patterns. It is shown also, that the period of Moiré patterns inside the crystal does not depend on the wavelength, whereas outside the crystal, this dependence is of a periodic character. The period is reduced along with an increase in the order. [Russian Text Ignored].
In DT plasmas, toroidal Alfvén eigenmodes (TAEs) can be made unstable by the alpha particles resulting from fusion reactions, and may induce a significant redistribution of fast ions. Recent experiments have been conducted in JET deuterium plasmas in order to prepare scenarios aimed at observing alpha-driven TAEs in a future JET DT campaign. Discharges at low density, large core temperatures associated with the presence of internal transport barriers and characterised by good energetic ion confinement have been performed. ICRH has been used in the hydrogen minority heating regime to probe the TAE stability. The consequent presence of MeV ions has resulted in the observation of TAEs in many instances. The impact of several key parameters on TAE stability could therefore be studied experimentally. Modeling taking into account NBI and ICRH fast ions shows good agreement with the measured neutron rates, and has allowed predictions for DT plasmas to be performed.
The influence of the surface and of the bulk defects upon the intensity of X-ray scattering is considered. It is shown that in particular cases the deformation of the crystal leads to a more efficient increase of diffracted waves than the attenuation of the waves propagating at an angle different from the strict Bragg angle. Der Einfluß der Oberfläche und von Volumendefekten auf die Intensität der Röntgenstreuung wird untersucht. Es wird gezeigt, daß in speziellen Fällen die Kristalldeformation zu einem wirksamerem Anwachsen der Beugungswellen als zu einer Dämpfung der Wellen führt, die sich unter einem vom exakten Bragg-Winkel verschiedenem Winkel ausbreiten.
This paper develops a global model based on non-local properties of fractional derivatives for fusion plasmas. The results confirm that transport in the largest fusion device i.e. JET, is better predicted. The model is expected to provide an insight to the proper kinetic description for the fusion plasmas, and to improve the accuracy of the transport predictions.
Abstract We present a new code for the tracing of magnetic field lines and calculation of related quantities such as the squashing factor in the solar corona. The Universal Fieldline Tracer ( UFiT ) is an open-source package that can currently take inputs directly from four well-established coronal models, with additional models planned to be made directly accessible in the future. This package contains tools to make use of large-scale three-dimensional field line maps to calculate volumetric quantities, such as the total volume of the open corona, or the fraction that maps to regions on the solar surface within some distance of a coronal hole boundary, which may be relevant to phenomenological models of solar wind speed such as the Wang–Sheeley–Arge model. Synthetic coronagraphs can also be produced rapidly by this package. We have postprocessed long-term magnetofrictional simulations to demonstrate that the separatrix web occupies a larger fraction of the corona during solar maximum than solar minimum.
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)
