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Relativistic multistage resonant and trailing-field acceleration induced by large-amplitude Alfvén waves in a strong magnetic field

Physical Review E (Plasma physics) - Tue, 11/04/2025 - 10:00

Author(s): S. Isayama, S. Matsukiyo, T. Sano, and S. H. Chen

This study addresses particle acceleration up to relativistic energies via a nonlinear evolution of a large-amplitude Alfvén wave. A multistage process is observed in numerical particle-in-cell simulations. The results provide insights into coherent wave-particle interactions in collisionless plasmas with potential implications for the understanding of high-energy cosmic-ray generation in astrophysical environments such as pulsar magnetospheres, accretion disks, and relativistic jets.

#AdvancingField


[Phys. Rev. E 112, 055201] Published Tue Nov 04, 2025

Strong-field ionization in particle-in-cell simulations

Physical Review E (Plasma physics) - Tue, 11/04/2025 - 10:00

Author(s): A. A. Mironov, E. G. Gelfer, I. I. Tupitsyn, A. Beck, M. Jirka, O. Klimo, S. Meuren, G. Oberreit, T. Smorodnikova, R. Taïeb, S. Weber, C. Riconda, M. Grech, and S. V. Popruzhenko

The inclusion of the process of multiple ionization of atoms in high-intensity electromagnetic fields into particle-in-cell (PIC) codes applied to the simulation of laser-plasma interactions is a challenging task. In this paper, we first revisit ionization rates as given by the Smirnov-Chibisov and …


[Phys. Rev. E 112, 055202] Published Tue Nov 04, 2025

The 31 October 2025 fatal landslides in Chesongoch, Kenya

EOS - Tue, 11/04/2025 - 08:05

It is reported that 51 people have been killed by a series of debris flows in Kenya, triggered by heavy rainfall.

On 31 October 2025, heavy rainfall triggered a series of large landslides in the vicinity of Chesongoch in Elgeyo Marakwet County, Kenya. To date, 26 people are known to have been killed and it is believed that a further 25 are missing, although continued heavy rainfall has led to a suspension of the rescue efforts.

Chesongoch is located at [1.12864, 35.64426]. Immediately to the west lies the Elgeyo Escarpment, a part of the Great Rift Valley.

This is a Planet satellite image of the area captured on the day of the landslides, but before the rainfall arrived:-

The site of the 31 October 2025 landslides at Chesongoch, in Elgeyo Marakwet county, Kenya. Image copyright Planet, used with permission, dated 31 October 2025.

And here is the same area on 3 November 2025, after the disaster:-

The aftermath of the 31 October 2025 landslides at Chesongoch, in Elgeyo Marakwet county, Kenya. Image copyright Planet, used with permission, dated 3 November 2025.

And here is a slider to allow comparison:-

Images copyright Planet.

Note that the post-disaster image is a composite of two images taken at different times on 3 November, which is why there is a cloud with an apparently strange linear edge in the centre of the image.

The post-event image shows a series of large channelised debris flows that have started on the Elgeyo Escarpment and travelled towards the east. The precise number is unclear (there are further examples to the north of the area covered by the image) because of the cloud, but there are at least five complexes in the area. These are likely to have started as shallow failures on the higher slopes, and there is considerable evidence of them eroding their channels. This is the area around Chesongoch itself, for example:-

The aftermath of the 31 October 2025 landslides at Chesongoch, in Elgeyo Marakwet county, Kenya. Image copyright Planet, used with permission, dated 3 November 2025.

Note that on the lower slopes, some of the debris flows have escaped from the channel to flow across the open hillslopes. It is likely that this accounts for some of the fatalities.

We will need to await better imagery to understand fully the initiation of these landslides, but this is a very cloudy area.

On Sunday, a further landslide hit the area, striking the town of Kipkenda [0.76202, 35.54115] to the south of Chesongoch. It is reported that two people were killed.

In April 2020, this area was affected by another series of debris flows, killing 15 people.

Reference

Planet Team 2024. Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/

Return to The Landslide Blog homepage Text © 2023. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Crustal S-wave velocity structure beneath Gangwon Province, the Korean Peninsula, inferred from Helmholtz tomography

Geophysical Journal International - Tue, 11/04/2025 - 00:00
SummaryGangwon Province, located in the central part of the Korean Peninsula, features northeast–southwest faults and tectonic structures formed by plutonic intrusions. Despite decades of geological investigations from near-surface to the upper crust in Gangwon Province, the lithospheric structure of this region remains poorly understood. The primary objective of this study is to identify velocity anomalies potentially associated with plutonic intrusions and to elucidate the formation processes and mechanisms governing the crustal and upper mantle structures in this region. We employed Helmholtz tomography to generate phase-velocity maps for periods of 10–40 s using a dense seismic network of 101 stations. These maps were subsequently inverted to obtain an S-wave velocity model from the upper crust to the uppermost mantle. Our results reveal northeast–southwest-trending low-velocity anomalies along major faults in central to northern Gangwon Province (i.e. eastern Gyeonggi Massif), extending to depths of approximately 25–30 km. These low-velocity anomalies align with the orientations of Jurassic granitoid intrusions formed through partial melting processes. Additionally, we identified other low-velocity anomalies, likely formed by Late Cretaceous intrusions, which are oriented perpendicular to the major faults. In contrast, the southeastern Gangwon Province (i.e. Taebaeksan Basin) exhibits a distinctly different velocity structure, lacking features indicative of granitic intrusions and showing low-velocity anomalies confined to shallow depths. The pronounced low-velocity anomalies observed at depths of 5–10 km in Taebaeksan Basin are attributed to a complex fault zone influenced by Permo-Triassic collisional orogeny.

High-resolution CMIP6 models shown to better capture long-term precipitation trends in high mountain Asia

Phys.org: Earth science - Mon, 11/03/2025 - 21:57
High Mountain Asia (HMA), the source region of major Asian rivers, plays a vital role in sustaining downstream water and ecosystem security. Over the past 50 years, summer precipitation in HMA has exhibited a dipole pattern—drying in the south and moistening in the north.

Metal contamination reaches 'critical' level in Peruvian highlands, researchers warn

Phys.org: Earth science - Mon, 11/03/2025 - 21:54
One of the most iconic ecosystems of the Peruvian plateau, the Junín Lake basin, suffers from "critical" levels of arsenic, lead and cadmium contamination, leading to health risks including cancer, according to new analysis.

Radiocarbon analysis of turfgrasses can help cities measure greenhouse gas emissions

Phys.org: Earth science - Mon, 11/03/2025 - 21:51
Cities around the world are working to limit emissions of climate-warming greenhouse gases, but there have been few ways of measuring whether those gases are actually decreasing in any given municipality. In new research, University of California, Irvine scientists have created an effective method to measure greenhouse gas emissions around cities—something that can help local governments gauge the effectiveness of their emission-curbing programs.

Q&A: Rainfall tipping point predicts drought risk for crops

Phys.org: Earth science - Mon, 11/03/2025 - 21:40
It matters where the rain that irrigates your food comes from.

Corrigendum to “Examining the altitude dependence of meteor head echo plasma distributions with EISCAT and MAARSY”. [Adv. Space Res. 76(4) (2025) 2280–2294]

Publication date: Available online 30 October 2025

Source: Advances in Space Research

Author(s): Devin Huyghebaert, Juha Vierinen, Johan Kero, Ingrid Mann, Ralph Latteck, Daniel Kastinen, Sara Våden, Jorge L. Chau

Observing Disc’s Impact in the Modified Robe’s Problem

Publication date: Available online 30 October 2025

Source: Advances in Space Research

Author(s): Suman, Raj Mal Jat, Ram Kishor

GRACE-FO gravity field recovery from integer ambiguity resolved kinematic orbits and decorrelated stochastic model

Publication date: Available online 30 October 2025

Source: Advances in Space Research

Author(s): Geng Gao, Wei Zheng, Yongjin Sun, Jiankang Du, Yongqi Zhao, Minxing Zhao

Evaluating the Effectiveness of Remote Sensing Data for Assessing the Impact of El Niño–Southern Oscillation (ENSO) on Air Temperature in a Tropical Urban Environment

Publication date: Available online 30 October 2025

Source: Advances in Space Research

Author(s): Ricky Anak Kemarau, Oliver Valentine Eboy, Zaini Sakawi, Stanley Anak Suab

Comprehensive time-space-frequency domain assessment of multi-GNSS code and phase observable-specific biases from IGS analysis centers

Publication date: Available online 30 October 2025

Source: Advances in Space Research

Author(s): Ge Ge, Zhetao Zhang, Haijun Yuan, Huaqing Xu

Bifurcated Periodic Orbit Families Around Enceladus and Their Potential as Science Orbits

Publication date: Available online 30 October 2025

Source: Advances in Space Research

Author(s): Pengfei Lu, Yue Wang

Error analysis of a simulated Fe resonance wind temperature lidar using Frequency-scanning method and Three-frequency ratio method

Publication date: Available online 28 October 2025

Source: Advances in Space Research

Author(s): Duanchao Liu, Hanxian Fang, Jintai Li, Die Duan, Chao Xiao, Hongtao Huang, Ganming Ren

Temporal-Enhanced Transformer for Anomaly Detection in Spacecraft Irregular-Interval Telemetry

Publication date: Available online 28 October 2025

Source: Advances in Space Research

Author(s): Aixin Dai, Yancai Xiao, Fangyi Ren, Haikuo Shen, Shaodan Zhi, Biao Ma

The improved Taiwan Ionospheric Model (TWIM2) and its applications on equatorial ionospheric anomaly specifications

Publication date: Available online 28 October 2025

Source: Advances in Space Research

Author(s): Lung-Chih Tsai, Shin-Yi Su, Harald Schuh, Mohamad Mahdi Alizadeh, Jens Wickert

Integrated framework to K’sob Wadi watershed prioritization for soil and water conservation using morphometric analysis, LULC, and weighted sum approach

Publication date: Available online 28 October 2025

Source: Advances in Space Research

Author(s): Blissag Bilal, Kessar Cherif, Ayada Noureddine Larbi, Haddad Moussa, Yebdri Djilali

Life after death: How earthworms keep facilitating carbon capture

Phys.org: Earth science - Mon, 11/03/2025 - 18:24
Earthworms don't stop shaping soil processes when they die. A new study shows they can still help store carbon in the soil, even after death. "This is quite surprising," says lead author Tullia Calogiuri. "Most of our knowledge about earthworms comes from their activity while alive, such as burrowing, feeding, and producing feces. Finding that they also play a role after death is exciting."

Refined radar technique improves accuracy of hurricane wind estimates after landfall

Phys.org: Earth science - Mon, 11/03/2025 - 18:07
A paper authored by University of Alabama in Huntsville (UAH) graduate student Zeb Leffler has been published in the Geophysical Research Letters. The student's master's research addresses a long-standing challenge in meteorology: improving the accuracy of hurricane wind estimates after landfall. Knowing the exact strength of surface winds is crucial for effective risk communication and post-storm recovery efforts.

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