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High-coherence narrowband terahertz emission from a radially oscillating plasma oscillator

Physical Review E (Plasma physics) - Tue, 05/05/2026 - 10:00

Author(s): Manoj Kumar, Jaeho Lee, Dohyun Park, Inhyuk Nam, and Min Sup Hur

We present a method for generating a narrowband terahertz (THz) emission using a radially oscillating plasma oscillator formed in a plasma slab with a longitudinal paraboliclike density profile. Through quasi-three-dimensional particle-in-cell simulations, we observe more stable, longer-lived plasma…

[Phys. Rev. E 113, 055201] Published Tue May 05, 2026

Relamination: A mechanism that has been shaping continents for billions of years

Phys.org: Earth science - Tue, 05/05/2026 - 09:00

An international team led by researchers from the National Museum of Natural Sciences (MNCN-CSIC) has identified a key mechanism that has shaped Earth's continents over billions of years. This mechanism is the deep re-lamination of subducted continental crust, a process that explains the origin of certain magmas and offers a new perspective on continental evolution from the Archean (between 3.8 and 2.5 billion years ago) to recent times.

Near-Surface Imaging of Urban Environments Using Distributed Acoustic Sensing (DAS) and Finite Element Method (FEM) Model

Geophysical Journal International - Tue, 05/05/2026 - 00:00

SummaryShear-wave velocity imaging is key for near-surface geotechnical characterization of foundation soils, for subsurface anomaly detection, and for process monitoring in urban environments. In this study, we propose a workflow for characterizing metropolitan areas using ambient and anthropogenic noise records from distributed acoustic sensing (DAS) data collected on telecommunications fiber. We developed a finite-element model that computes shear-wave dispersion curves for fundamental and higher-order surface-wave modes from a layered velocity profile. The model parameters allow intralayer linear and power-law variations of velocity with depth to provide realistic near-surface soil behavior. The forward model is coupled with an inversion algorithm that minimizes the model’s misfit to dispersion curves derived from the DAS data. We demonstrate the workflow using DAS data collected on the University of Wisconsin-Madison’s campus network. The results are compared with the multichannel analysis of surface waves (MASW) method using a line of geophones co-located with one of the DAS sites and a nearby borehole log. Both solutions indicated a sharp change in shear-wave velocity at approximately 20 meters, corresponding to the depth of a sandstone formation at the site, and that a physically-based, power-law function better fits the velocity profiles of unconsolidated sediments. These results demonstrate that our method provides reliable near-surface imaging while suggesting likely soil types. The proposed measurements and modeling techniques can be extended to image the near surface wherever telecommunications fiber is available.

Want to predict wildfire severity? Research says look to the state of vegetation

Phys.org: Earth science - Mon, 05/04/2026 - 22:20

Urbanization, climate change, and fire suppression practices are contributing to increased wildfire risk at the densely populated wildland-urban interface. These factors make fires more unpredictable and harder to manage. In January 2025, this was made devastatingly clear in Los Angeles, when massive wildfires engulfed entire hillsides and canyons, destroying neighborhoods and damaging surrounding ecosystems.

Buried electrical pathways across the US reveal new clues about Earth's interior and power grid risks

Phys.org: Earth science - Mon, 05/04/2026 - 20:00

A solar storm like the one that caused a nine-hour blackout across Quebec in 1989 could have even more dramatic effects if it struck the eastern United States today. Now, scientists have developed new tools to detect these storms before they strike by mapping the hidden electrical structure beneath our feet, revealing how the ground itself could influence the impact on our power grid.

Looking Down: Where Terrestrial Weather May Help Space Weather

Recent articles in Advances in Space Research - Mon, 05/04/2026 - 19:11

Publication date: Available online 2 May 2026

Source: Advances in Space Research

Author(s): Edmund M. Henley, David R. Jackson, Mario M. Bisi, Maria M. Kuznetsova, Martin A. Reiss