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Randomization of a laser wave front by the turbulent gas-puff $Z$-pinch plasma column

Physical Review E (Plasma physics) - Tue, 04/08/2025 - 10:00

Author(s): A. Rososhek, E. S. Lavine, B. R. Kusse, W. M. Potter, and D. A. Hammer

In this paper, we present the first direct experimental evidence supported by numerical modeling of a turbulent plasma column formed during a gas-puff z-pinch implosion generated by the cobra current. Utilizing an imaging refractometer, we showed a significant decrease in spatial autocorrelation of …

[Phys. Rev. E 111, 045202] Published Tue Apr 08, 2025

Coherent puff and slugs in transitional drift-wave turbulence

Physical Review E (Plasma physics) - Tue, 04/08/2025 - 10:00

Author(s): P. Manz, S. Knauer, C. Moon, N. Fahrenkamp, D. Di Matteo, and A. Fujisawa

The long-term development of the transitional regime of drift-wave turbulence is studied in a magnetized plasma column by means of the conditional-average technique. In the transitional regime, small changes in the magnetic-field strength as control parameter lead to large changes in the correlation…

[Phys. Rev. E 111, 045203] Published Tue Apr 08, 2025

Mercury concentrations in tree rings may enable trees to be 'witnesses' of illegal gold mining activities in the Amazon

Phys.org: Earth science - Tue, 04/08/2025 - 04:00

For hundreds of years, the Amazon has been exploited for its gold. Today, the precious metal is just as sought after, but the remaining tiny gold particles are much harder to find. Mining often happens in artisanal and small-scale mining operations that release mercury (Hg) into the air, polluting the environment and harming human health.

Fault identification, complexity and evolution of the 2021, Atarfe-Santa Fe earthquake swarm (Granada basin, Spain)

Geophysical Journal International - Tue, 04/08/2025 - 00:00

SummarySeismic swarms are known to occur in regions with complex deformation and multiple fault systems. The identification of the affected faults, the evolution of the seismicity and the rupture characteristics are key to understand seismotectonics and seismic hazard of such areas. We here address the Atarfe-Santa Fe earthquake swarm with > 5000 events, including six magnitude 4+ earthquakes, recorded in 2021 in the Granada Basin area (S-Spain). We use continuous data from a dense local recording network and apply deep learning models to pick and associate seismic phase arrivals and construct an automatic event catalogue. A double difference relocation of 3196 earthquakes reveals the seismotectonic fine-structure of the swarm. We identify planar, southwest-dipping structures among the relocated hypocentres, consistent with the NW-SE trending, high-angle normal faults present in this sector of the Granada basin. Earthquakes concentrate between 4-7 km depth along three different lineaments. The distinctive pattern of three equidistant, parallel segments allows an association of the swarm with the Ermita los Tres Juanes, Atarfe and Pinos Puente normal faults. These faults outcrop at the upward extrapolation of the swarm, forming an arrangement of three structures that mimic the geometry of the relocated seismicity at depth. In the course of the swarm, the seismicity jumped from the Ermita los Tres Juanes to the Atarfe fault, in midst of a rapid succession of three magnitude 4 earthquakes within 20 minutes, then migrated laterally along both faults, and later migrated basinwards to the Pinos Puente fault, which produced fewer and smaller events. We estimate apparent source time functions for five earthquakes (Mw 4.1 to 4.4) through the deconvolution of empirical Green's functions from the records, suggesting rupture propagation towards NW, N and E directions. An isochrone back projection of apparent source time functions suggests km-scale ruptures with simple slip distributions, showing lateral and updip components of rupture. Our results shed light on the complexity of this seismic swarm in terms of the fault network involved, the propagation of seismicity across the faults and the variable directions of individual ruptures.