1. Light-Induced Magnetization at the NanoscaleJonas Wätzel, Primož Rebernik Ribič, Marcello Coreno, Miltcho Danailov, Christian David, Alexander Demidovich, Michele Di Fraia, Luca Giannessi, Klavs Hansen, Špela Krušič, Michele Manfredda, Michael Meyer, Andrej Mihelič, Najmeh Mirian, Oksana Plekan, Barbara Ressel, Benedikt Rösner, Alberto Simoncig, Simone Spampinati, Matija Stupar, Matjaž Žitnik, Marco Zangrando, Carlo Callegari, Jamal Berakdar, Giovanni De Ninno, 2022, izvirni znanstveni članek Ključne besede: FEL, orbital angular momentum, magnetisation
Objavljeno v RUNG: 16.01.2023; Ogledov: 893; Prenosov: 0
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3. Photoelectric effect with a twistGiovanni De Ninno, Jonas Wätzel, Primož Rebernik Ribič, Enrico Allaria, Marcello Coreno, Miltcho B. Danailov, Christian David, Alexander Demidovich, Michele Di Fraia, Luca Giannessi, Klaus Hansen, Špela Krušič, Michele Manfredda, Micheal Meyer, Andrej Mihelič, Najmeh Mirian, Oksana Plekan, Barbara Ressel, Benedikt Rösner, Alberto Simoncig, Simone Spampinati, Janez Štupar, Matjaž Žitnik, Marco Zangrando, Carlo Callegari, Jamal Berakdar, 2020, izvirni znanstveni članek Opis: Photons have fixed spin and unbounded orbital angular momentum (OAM). While the former is manifested in the polarization of light, the latter corresponds to the spatial phase distribution of its wavefront1. The distinctive way in which the photon spin dictates the electron motion upon light– matter interaction is the basis for numerous well-established spectroscopies. By contrast, imprinting OAM on a mat- ter wave, specifically on a propagating electron, is gener- ally considered very challenging and the anticipated effect undetectable2. In refs. 3,4, the authors provided evidence of OAM-dependent absorption of light by a bound electron. Here, we seek to observe an OAM-dependent dichroic photo- electric effect, using a sample of He atoms. Surprisingly, we find that the OAM of an optical field can be imprinted coher- ently onto a propagating electron wave. Our results reveal new aspects of light–matter interaction and point to a new kind of single-photon electron spectroscopy.
Ključne besede: FEL, OAM, Photoelectric effect
Objavljeno v RUNG: 09.09.2020; Ogledov: 2861; Prenosov: 0
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4. Lidar Observations of Mountain Waves During Bora EpisodesLonglong Wang, Marija Bervida, Samo Stanič, Klemen Bergant, William Eichinger, Benedikt Strajnar, 2020, objavljeni znanstveni prispevek na konferenci Opis: Airflows over mountain barriers in the Alpine region may give rise to strong, gusty downslope winds, called Bora. Oscillations, caused by the flow over an orographic barrier, lead to formation of mountain waves. These waves can only rarely be observed visually and can, in general, not be reliably reproduced by numerical models. Using aerosols as tracers for airmass motion, mountain waves were experimentally observed during Bora outbreak in the Vipava valley, Slovenia, on 24-25 January 2019 by two lidar systems: a vertical scanning lidar positioned just below the peak of the lee side of the mountain range and a fixed direction lidar at valley floor, which were set up to retrieve two-dimensional structure of the airflow over the orographic barrier into the valley. Based on the lidar data, we determined the thickness of airmass layer exhibiting downslope motion, observed hydraulic jump phenomena that gave rise to mountain waves and characterized their properties.
Ključne besede: Bora, mountain waves, lidar observations
Objavljeno v RUNG: 08.07.2020; Ogledov: 2710; Prenosov: 0
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5. High resolution beam profiling of X-ray free electron laser radiation by polymer imprint developmentBenedikt Rösner, Florian Döring, Primož Rebernik Ribič, David Gauthier, Emiliano Principi, Claudio Masciovecchio, Marco Zangrando, Joan Vila-Comamala, Giovanni De Ninno, Christian David, 2017, izvirni znanstveni članek Ključne besede: free-electron lasers, metrology, polymers, X-ray optics
Objavljeno v RUNG: 13.01.2020; Ogledov: 2992; Prenosov: 0 |
6. Near-Ground Profile of Bora Wind Speed at Razdrto, SloveniaMarija Bervida, Samo Stanič, Klemen Bergant, Benedikt Strajnar, 2019, izvirni znanstveni članek Opis: Southwest Slovenia is a region well-known for frequent episodes of strong and gusty Bora wind, which may damage structures, affect traffic, and poses threats to human safety in general. With the increased availability of computational power, the interest in high resolution modeling of Bora on local scales is growing. To model it adequately, the flow characteristics of Bora should be experimentally investigated and parameterized. This study presents the analysis of wind speed vertical profiles at Razdrto, Slovenia, a location strongly exposed to Bora during six Bora episodes of different duration, appearing between April 2010 and May 2011. The empirical power law and the logarithmic law for Bora wind, commonly used for the description of neutrally stratified atmosphere, were evaluated for 10-min averaged wind speed data measured at four different heights. Power law and logarithmic law wind speed profiles, which are commonly used in high resolution computational models, were found to approximate well the measured data. The obtained power law coefficient and logarithmic law parameters, which are for modeling purposes commonly taken to be constant for a specific site, were found to vary significantly between different Bora episodes, most notably due to different wind direction over complex terrain. To increase modeling precision, the effects of local topography on wind profile parameters needs to be experimentally assessed and implemented.
Ključne besede: Bora wind, logarithmic law, power law, roughness length, wind profile
Objavljeno v RUNG: 04.10.2019; Ogledov: 3434; Prenosov: 108
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7. Lidar measurements of Bora wind effects on aerosol loadingMaruška Mole, Longlong Wang, Samo Stanič, Klemen Bergant, William Eichinger, Francisco Ocaña, Benedikt Strajnar, Primož Škraba, Marko Vučković, William Willis, 2017, izvirni znanstveni članek Opis: The Vipava valley in Slovenia is well known for the appearance of strong, gusty North-East Bora winds, which occur as a result of air
flows over an adjacent orographic barrier. There are three revealing wind directions within the valley which were found to give rise to
specific types of atmospheric structures. These structures were investigated using a Mie scattering lidar operating at 1064 nm, which provided high temporal and spatial resolution backscatter data on aerosols, which were used as tracers for atmospheric flows. Wind
properties were monitored at the bottom of the valley and at the rim of the barrier using two ultrasonic anemometers. Twelve time periods between February and April 2015 were selected when lidar data was available. The periods were classified according to the wind speed and direction and investigated in terms of appearance of atmospheric structures. In two periods with strong or moderate Bora, periodic atmospheric structures in the lidar data were observed at heights above the mountain barrier and are believed to be Kelvin–Helmholtz waves, induced by wind shear. No temporal correlation was found between these structures and wind gusts at the ground level. The influence of the wind on the height of the planetary boundary layer was studied as well. In periods with low wind speeds, the vertical evolution of the planetary boundary layer was found to be governed
by solar radiation and clouds. In periods with strong or moderate Bora wind, convection within the planetary boundary layer was found to be much weaker due to strong turbulence close to the ground, which inhibited mixing through the entire layer.
Ključne besede: Downslope wind
Lidar observations
Kelvin–Helmholtz waves
Bora
Objavljeno v RUNG: 06.01.2017; Ogledov: 5313; Prenosov: 0
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