Scaling Behavior of Quasi-One-Dimensional Vortex Avalanches in Superconducting Films

Scaling behaviour of dynamically driven vortex avalanches in superconducting YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ films deposited on tilted crystalline substrates has been observed using quantitative magneto-optical imaging. Two films with different tilt angles are characterized by the probability distributions of avalanche size in terms of the number of moving vortices. It is found in both samples that these distributions follow power-laws over up to three decades, and have exponents ranging between 1.0 and 1.4. The distributions also show clear finite-size scaling, when the system size is defined by the depth of the flux penetration front -- a signature of self-organized criticality. A scaling relation between the avalanche size exponent and the fractal dimension, previously derived theoretically from conservation of the number of magnetic vortices in the stationary state and shown in numerical simulations, is here shown to be satisfied also experimentally.Comment: 7 pages, 5 figure

Quasi-one-dimensional intermittent flux behavior in superconducting films

Intermittent filamentary dynamics of the vortex matter in superconductors is found in films of YBa2Cu3O7-δ deposited on tilted substrates. Deposition of this material on such substrates creates parallel channels of easy flux penetration when a magnetic field is applied perpendicular to the film. As the applied field is gradually increased, magneto-optical imaging reveals that flux penetrates via numerous quasi-one-dimensional jumps. The distribution of flux avalanche sizes follows a power law, and data collapse is obtained by finite-size scaling, with the depth of the flux front used as crossover length. The intermittent behavior shows no threshold value in the applied field, in contrast to conventional flux jumping. The results strongly suggest that the quasi-one-dimensional flux jumps are of a different nature than the thermomagnetic dendritic (branching) avalanches that are commonly found in superconducting films

Salmon lice (Lepeophtheirus salmonis) in the stomach contents of lumpfish (Cyclopterus lumpus) sampled from Norwegian fish farms: Relationship between lice grazing and operational conditions

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Energy of dendritic avalanches in thin-film superconductors

A method for calculating stored magnetic energy in a thin superconducting film based on quantitative magneto-optical imaging is developed. Energy and magnetic moment are determined with these calculations for full hysteresis loops in a thin film of the superconductor NbN. Huge losses in energy are observed when dendritic avalanches occur. Magnetic energy, magnetic moment, sheet current and magnetic flux distributions, all extracted from the same calibrated magneto-optical images, are analyzed and discussed. Dissipated energy and the loss in moment when dendritic avalanches occur are related to each other. Calculating these losses for specific spatially-resolved flux avalanches is a great advantage, because of their unpredictable and non-reproducible nature. The relative losses in energy are much higher than the relative losses in moment

Energy of dendritic avalanches in thin-film superconductors

A method for calculating stored magnetic energy in a thin superconducting film based on quantitative magneto-optical imaging is developed. Energy and magnetic moment are determined with these calculations for full hysteresis loops in a thin film of the superconductor NbN. Huge losses in energy are observed when dendritic avalanches occur. Magnetic energy, magnetic moment, sheet current and magnetic flux distributions, all extracted from the same calibrated magneto-optical images, are analyzed and discussed. Dissipated energy and the loss in moment when dendritic avalanches occur are related to each other. Calculating these losses for specific spatially-resolved flux avalanches is a great advantage, because of their unpredictable and non-reproducible nature. The relative losses in energy are much higher than the relative losses in moment

Rapidity and centrality dependence of particle production for identified hadrons in Cu+Cu collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

The BRAHMS collaboration has measured transverse momentum spectra of pions, kaons, protons and antiprotons at rapidities 0 and 3 for Cu+Cu collisions at $\sqrt{s_{NN}} = 200$ GeV. As the collisions become more central the collective radial flow increases while the temperature of kinetic freeze-out decreases. The temperature is lower and the radial flow weaker at forward rapidity. Pion and kaon yields with transverse momenta between 1.5 and 2.5 GeV/c are suppressed for central collisions relative to scaled $p+p$ collisions. This suppression, which increases as the collisions become more central is consistent with jet quenching models and is also present with comparable magnitude at forward rapidity. At such rapidities initial state effects may also be present and persistence of the meson suppression to high rapidity may reflect a combination of jet quenching and nuclear shadowing. The ratio of protons to mesons increases as the collisions become more central and is largest at forward rapidities.Comment: 19 pages, 11 figures and 6 table

Vurdering av heterogenitet i lakselusindusert villfiskdødelighet innen produksjonsområder i 2022. Oppdatert med nye modeller

Ekspertgruppen oppnevnt til å vurdere lakselusindusert villfiskdødelighet på utvandrende laksesmolt har fått i oppdrag å vurdere heterogeniteten i dødelighet mellom vassdrag, det vil si om det er stor forskjell i dødelighet av smolt fra forskjellige vassdrag innen samme produksjonsområde (PO). Dette er viktig ettersom heterogenitet kan føre til at noen bestander kan bli mer påvirket enn det gjennomsnittet for POet tilsier (Vollset mfl. 2022). Kort oppsummert vurderer vi først om smittepresset og dødelighetsestimater varierer innad i produksjonsområdet, og deretter om denne variasjonen fører til at grupper av spesielt sårbare og viktige bestander har høyere dødelighet enn den mest sannsynlige dødelighetskategorien for hele POet. Vi rapporterer også om det er enkeltbestander som påvirkes mer enn den mest sannsynlige dødelighetskategorien for det POet bestanden tilhører. Resultatene for 2022 viser at det i ett PO var grupper av sårbare og viktige bestander med sannsynlighetsovervekt for at lakselusindusert dødelighet var høyere enn den mest sannsynlige dødelighetskategorien for POet: • Bestander med dårlig eller svært dårlig tilstand etter delnormen “Gytebestandsmål og høstingspotensial” i kvalitetsnormen i PO10. I ytterligere fem POer tyder resultater fra én eller flere virtuelle postsmoltmodeller på at enkeltbestander hadde høyere lakselusindusert dødelighet enn den mest sannsynlige dødelighetskategorien for POet. Dette gjaldt også enkelte av bestandene innenfor de følgende kategoriene av sårbare og viktige bestander: • Nasjonale laksevassdrag, bestander med dårlig eller svært dårlig tilstand etter delnormen “Gytebestandsmål og høstingspotensial” i kvalitetsnormen, små og sårbare bestander og bestander under reetablering i PO6. • Små og sårbare bestander i PO7. • Bestander med dårlig eller svært dårlig tilstand etter delnormen “Gytebestandsmål og høstingspotensial” i kvalitetsnormen og små og sårbare bestander i PO9. • Nasjonale laksevassdrag i PO11. • Nasjonale laksevassdrag og små og sårbare bestander i PO12. I fem POer tilsa ikke resultatene at enkeltbestander hadde høyere dødelighet enn den mest sannsynlige dødelighetskategorien for POet. Dette gjaldt: • PO1, PO2, PO5, PO8 og PO13. I to POer var den mest sannsynlige dødelighetskategorien over 30 %, og heterogenitetsvurderinger ikke relevante. Dette gjaldt: • PO3 og PO4