1,720,988 research outputs found
An annual electricity market simulator: model description and application in a pan-European framework
Full text linkTarget Normal Sheath Acceleration at ultrahigh intensities: A theoretical parametric investigation
No full textIons can be effectively accelerated during the interaction of an ultra-intense ultra-short laser pulse irradiating a thin solid target via the so-called Target Normal Sheath Acceleration (TNSA) mechanism. One of the crucial issues at this stage of the research is how to predict the properties of the accelerated ions, both from a fundamental point of view and in the light of foreseen applications. Thus, it is desirable to have a simple but reliable description, to be used to extrapolate current results to regimes likely to be reached in the near future, thanks to developments in laser technology. In this work we theoretically investigated the maximum ion energy achieved in TNSA as a function of laser properties, with special focus to the ranges I_L (pulse intensity) 10^20 -10^22 W/cm^2 and E_L (pulse energy) 1-30 J, which appear to be the most interesting for future facilities. Particular attention will be devoted to elucidate the effective dependence of the maximum ion energy on the laser intensity for different combinations of laser parameters
Energetic ions from next generation ultraintense ultrashort lasers: Scaling laws for Target Normal Sheath Acceleration
No full textLaser-driven ion acceleration represents one of the most exciting topics related to the physics of laser-plasma interaction. Ions can be effectively accelerated up to multi-MeV energies via the so-called Target Normal Sheath Acceleration (TNSA) mechanism. The possibility of predicting the properties of the accelerated ions is definitely a crucial issue, both from a fundamental point of view and in the light of foreseen applications. In this work the problem of the dependence of the maximum ion energy achieved in TNSA on the laser properties is theoretically investigated. Particular attention is devoted to elucidate the role played by the various laser parameters, like power, intensity, energy and focal spot, in determining the maximum ion energy, with special focus to values relevant for the present and next generation of Ti:Sa laser systems
Can music be figurative? Exploring the possibility of crossmodal similarities between music and visual arts
Full text linkAccording to both experimental research and common sense, classical music is a better fit for figurative art than jazz. We hypothesize that similar fits may reflect underlying crossmodal structural similarities between music and painting genres. We present two preliminary studies aimed at addressing our hypothesis. Experiment 1 tested the goodness of the fit between two music genres (classical and jazz) and two painting genres (figurative and abstract). Participants were presented with twenty sets of six paintings (three figurative, three abstract) viewed in combination with three sound conditions: 1) silence, 2) classical music, or 3) jazz. While figurative paintings scored higher aesthetic appreciation than abstract ones, a gender effect was also found: the aesthetic appreciation of paintings in male participants was modulated by music genre, whilst music genre did not affect the aesthetic appreciation in female participants. Our results support only in part the notion that classical music enhances the aesthetic appreciation of figurative art. Experiment 2 aimed at testing whether the conceptual categories ‘figurative’ and ‘abstract’ can be extended also to music. In session 1, participants were first asked to classify 30 paintings (10 abstract, 10 figurative, 10 ambiguous that could fit either category) as abstract or figurative and then to rate them for pleasantness; in session 2 participants were asked to classify 40 excerpts of music (20 classical, 20 jazz) as abstract or figurative and to rate them for pleasantness. Paintings which were clearly abstract or figurative were all classified accordingly, while the majority of ambiguous paintings were classified as abstract. Results also show a gender effect for painting’s pleasantness: female participants rated higher ambiguous and abstract paintings. More interestingly, results show an effect of music genre on classification, showing that it is possible to classify music as figurative or abstract, thus supporting the hypothesis of cross-modal similarities between the two sensory-different artistic expressions
Ultra-low density carbon foams produced by pulsed laser deposition
No full textWe report on the manufacturing of ultra-lowdensity carbon foam produced by pulsed laser deposition. Mean mass density, morphology and structure were investigated within a broad range of process parameters.We have been able to obtain carbon foam layers having tun- able mean density and thickness in the range 1–1000 mg/cm^3 and 5–80 micron, respectively.
Surface uniformity has been achieved over 1 micron^2 areas with mean pore size around 10 nm. The morphological/structural properties have been investigated by means of quartz crystal microbalance, scanning electron microscopy and Raman spectroscopy. Based on these results, this work shows how pulsed laser deposition can be exploited as a versatile tool for the deposition of carbon foams with tunable and tailored density, thickness and uniformity
Energy dispersive x-ray spectroscopy for nanostructured thin film density evaluation
Full text linkIn this paper, we report on two fast and non-destructive methods for nanostructured film density evaluation based on a combination of energy dispersive x-ray spectroscopy for areal density measurement and scanning electron microscopy (SEM) for thickness evaluation. These techniques have been applied to films with density ranging from the density of a solid down to a few mg cm(-3), with different compositions and morphologies. The high resolution of an electron microprobe has been exploited to characterize non-uniform films both at the macroscopic scale and at the microscopic scale
Target normal sheath acceleration: theory, comparison with experiments and future perspectives
No full textIons can be effectively accelerated during the interaction of an ultraintense ultra-short laser pulse irradiating a thin solid target via the so-called target normal sheath acceleration (TNSA) mechanism. One of the pivotal questions at this stage of the research is how to predict the properties of the accelerated ions, both from a fundamental point of view and in the light of foreseen applications.
In this context, it is desirable to have a simple but reliable description to be used to extrapolate current results to future regimes, which will be made available in the near future, thanks to developments in laser technology. In this paper, the possible approaches for an analytical description of TNSA are discussed, and
a theoretical TNSA model is developed. This model is then used to investigate the maximum ion energy as a function of laser parameters. Detailed comparisons with available experimental data and scaling laws are presented. In particular, the relative role played by both the laser pulse energy and irradiance in determining
the ion features is investigated
Parametric investigations of target normal sheath acceleration experiments
No full textOne of the most important challenges related to laser-driven ion acceleration research is to actively control some important ion beam features. This is a peculiar topic in the light of future possible technological applications. In the present work we make use of one theoretical model for target normal sheath acceleration in order to reproduce recent experimental parametric studies about maximum ion energy dependencies on laser parameters. The key role played by pulse energy and intensity is enlightened. Finally the effective dependence of maximum ion energy on intensity is evaluated using a combined theoretical approach, obtained by means of an analytical and a particle-in-cell numerical investigation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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