ODS+Hf and AISI 316L steel surface variations at high laser intensity, 1013 W/cm2, in air and vacuum: comparative study

The behavior of Oxide Dispersion Strengthened (ODS) steel with addition of hafnium, as well as AISI 316L steel, at high laser intensity of ~1013 W/cm2 in ambiences of air and vacuum, was studied. Irradiation source was Ti:Sapphire laser operating at 804 nm and pulse length of ~65 fs. Morphological and chemical studies were considered, thus that: (i) given laser intensity induced damages on both steels with the damage being more prominent on AISI 316L steel; (ii) various surface features were present, such as coral-like structure and Laser Induced Periodic Surface Structures (LIPSS), with LIPSS being dominant on the surface; (iii) the interaction was accompanied by generation of plasma above the target, and (iv) chemical analysis has shown that surface elemental content also depends on the ambience used.SPIG 2022 : 31st Summer School and International Symposium on the Physics of Ionized Gases : Contributed papers and abstracts of invited lectures, topical invited lectures and progress reports; September 5-9,2022, Belgrad

Innovative education and training in high power laser plasmas (PowerLaPs) for plasma physics, high power laser matter interactions and high energy density physics: experimental diagnostics and simulations

The second and final year of the Erasmus Plus programme "Innovative Education and Training in high power laser plasmas", otherwise known as PowerLaPs, is described. The PowerLaPs programme employs an innovative paradigm in that it is a multi-centre programme where teaching takes place in five separate institutes with a range of different aims and styles of delivery. The "in class" time is limited to four weeks a year, and the programme spans two years. PowerLaPs aims to train students from across Europe in theoretical, applied, and laboratory skills relevant to the pursuit of research in laser plasma interaction physics and inertial confinement fusion (ICF). Lectures are intermingled with laboratory sessions, and continuous assessment activities. The programme, which is led by workers from the Hellenic Mediterranean University, and supported by co-workers from Queens University Belfast, the University of Bordeaux, the Czech Technical University in Prague, Ecole Polytechnique, the University of Ioannina, the University of Salamanca, and the University of York, has just finished its second and final year. Six Learning Teaching Training (LTT) activities have been held, at the Queens University Belfast, the University of Bordeaux, the Czech Technical University, the University of Salamanca, and the Institute of Plasma Physics and Lasers (CPPL) of the Hellenic Mediterranean University. The last of these institute hosted two two-week long Intensive Programmes (IPs), whilst the activities at the other four universities were each five days in length. In addition to this a "Multiplier Event" was held at the University of Ioannina, which will be briefly described. In this second year the work has concentrated upon training in both experimental diagnostics and simulation techniques appropriate to the study of Plasma Physics, High Power Laser-Matter Interactions and High Energy Density Physics. The nature of the programme will be described in detail and some metrics relating to the activities carried out will be presented. In particular this paper will focus upon the overall assessment of the programme

Innovative Education and Training in high power laser plasmas (PowerLaPs) for plasma physics, high power laser-matter interactions and high energy density physics - Theory and experiments

The Erasmus Plus programme 'Innovative Education and Training in high power laser plasmas', otherwise known as PowerLaPs, is described. The PowerLaPs programme employs an innovative paradigm in that it is a multi-centre programme where teaching takes place in five separate institutes with a range of different aims and styles of delivery. The 'in class' time is limited to four weeks a year, and the programme spans two years. PowerLaPs aims to train students from across Europe in theoretical, applied and laboratory skills relevant to the pursuit of research in laser-plasma interaction physics and inertial confinement fusion (ICF). Lectures are intermingled with laboratory sessions and continuous assessment activities. The programme, which is led by workers from the Technological Educational Institute (TEI) of Crete, and supported by co-workers from the Queen's University Belfast, the University of Bordeaux, the Czech Technical University in Prague, Ecole Polytechnique, the University of Ioannina, the University of Salamanca and the University of York, has just completed its first year. Thus far three Learning Teaching Training (LTT) activities have been held, at the Queen's University Belfast, the University of Bordeaux and the Centre for Plasma Physics and Lasers (CPPL) of TEI Crete. The last of these was a two-week long Intensive Programme (IP), while the activities at the other two universities were each five days in length. Thus far work has concentrated upon training in both theoretical and experimental work in plasma physics, high power laser-matter interactions and high energy density physics. The nature of the programme will be described in detail and some metrics relating to the activities carried out to date will be presented

Ultrashort laser - fusion material interaction

Nuclear fusion (NF) as a source of clean energy is of interest to many governments, research groups, etc., nowadays. In order for NF to be applied in full capacity, certain problems related to plasma physics and reactor technology should be overcome [1]. In the main, there are two approaches at this moment, the first one based on magnetic confinement and the second one based on inertial confinement fusion, i.e. laser concept. Focusing only on the reactor technology, it is of high importance, among other, to apply the reactor materials (RM) possessing high resistance to thermal and radiation (including electromagnetic) flux [2]. In this context, the behavior of fusion RM, particularly potential plasma facing materials (PFM), will be observed. In nuclear reactor, the PFM are exposed to various fluxes such as the neutrons, alfa-particles, electromagnetic, thermal, hydrogen isotopes. These high thermal as well as electromagnetic fluxes can be, in one approximation, simulated by high-intensity laser radiation [3, 4]. Examples of high intensity femtosecond laser – material interaction will be presented in this work. The materials, i.e. candidates for PFM like tungsten, oxide dispersion strengthened (ODS) steel, will be investigated under the action of high laser intensity of the order of 1014 W/cm2 [5, 6]. Also, the presence of hydrogen isotopes in PFM will be analyzed.AMPL-2021 : 15th International conference Pulsed Lasers and Laser Applications : Book of abstracts; September 12–17, 2021, Tomsk, Russi

Femtosecond laser-assisted surface modification of tungsten with 1015 W/cm2 intensity in air and vacuum ambience

The present study deals with modification of tungsten surface with high-intensity (∼1015 W/cm2) femtosecond laser in air and vacuum surrounding. Specific findings include: (a) the applied intensities produce crater-like damages with depth ∼31.0 μm in vacuum and ∼7.2 μm in air; (b) peripheral region of the damages is diffuse in air atmosphere unlike vacuum where it is more sharply defined; (c) hydrodynamic features, while present in vacuum, are dramatically reduced in air; (d) characteristic chemical surface changes occur at the surface, and (e) plasma forms in front of the target in both surroundings. The obtained results imply that the employed intensities, in a certain sense, can be used for simulation of some processes in the fusion reactor and for highly precise material removal and tungsten surface processing (by fine tuning of given fs laser parameters). © 2018 Elsevier B.V

Effects of Laser Radiation at 10 13 W/cm2 Intensity on Ferritic ODS Steel With and Without Hf in Helium and Vacuum

Ferritic 16Cr3Al ODS steel, with and without the addition of hafnium, was exposed to high-intensity laser radiation of the order of 1013 W/cm2. Irradiation was conducted in the environments of helium and vacuum and the obtained surface effects were observed in the sense of morphology and chemical changes. This class of steels is being developed primarily for structural applications in nuclear reactors, which is why their behavior under harsh conditions, including high power densities, is of utmost importance. The obtained results show mostly superficial changes even at a high number of pulses, which points toward the successful implementation of these materials in a number of applications involving severe work conditions

Surface behavior of 16Cr3Al ODS steel—Effects of high laser intensity 1014 W/cm2 in ambiences of air, helium and vacuum

The behavior of 16Cr3Al ODS steel (oxide dispersion strengthened steel), widely employed structural fusion material, under high-intensity laser radiation with intensity up to 10(14)W/cm(2) was investigated in air, helium and vacuum surrounding. Employed system was 65 fs laser at 804 nm, with applied pulse energy up to 5.25 mJ. Morphological effects were studied - cracking, crater parameters (depth, cross-section), LIPSS (laser-induced periodic surface structures) formation at the crater periphery, hydrodynamic effects, as well as chemical variations on the surface. Ablation thresholds were also determined for all three ambiences (for 100 applied pulses), and they were 0.30 J/cm(2), 0.23 J/cm(2) and 0.39 J/cm(2) in air, helium and vacuum, respectively. Plasma occurred in all experiments and it was most prominent in vacuum due to strongest laser-material coupling

16Cr3Al-Hf ODS steel: Surface effects of high laser intensity of 1015 W/cm2 in ambiences of air, helium and vacuum

Behavior of ODS steel under high energy fluxes is important as it is one of the most promising fusion reactor materials. The addition of hafnium provides improved microstructure and therefore better mechanical properties at high temperatures, and the goal here was to investigate the effects induced on Hf-containing ODS steel by the action of high-intensity ∼1015 W/cm2 radiation obtained by ultrashort pulsed laser. Morphological and chemical parametric study of the surface was conducted at different work ambiences. New data were obtained on damage parameters, threshold fluences and chemical changes. Measured damage depths were ∼7.5 μm (air), ∼14 μm (helium), ∼48 μm (vacuum), which is somewhat lower compared to ODS steel without the addition of hafnium