Results 51 to 60 of about 91,577 (233)

Magnetic location of a possible earthquake epicentre area: a mathematical model

Geomatics, Natural Hazards & Risk, 2016
We study one of the problems of the theory of seismo-electromagnetic methods of earthquake prediction, namely, the physical nature of magnetic location of a future epicentre.
O.B. Novik, S.V. Ershov, M.N. Volgin, A.O. Novik   +3 more
doaj   +1 more source

Magnetic Flux Ropes at Mars and Their Impacts on Heavy Ion Escape

Geophysical Research Letters, Volume 52, Issue 20, 28 October 2025.
Abstract Flux ropes (FRs), ubiquitous helical magnetic structures in solar system plasmas, are important to energy and particle transport. At Mars, where global intrinsic magnetic fields are absent, FRs form through magnetic reconnection (MR) and magnetospheric or ionospheric boundary wave instabilities (BWIs), but their role in ion escape remains ...
Jinqiao Fan, Yasong S. Ge, Can Huang, Aimin Du, Xiaohua Fang, Tielong Zhang, Yingjuan Ma, Lei Wang, Ziyong Liu   +8 more
wiley   +1 more source

Continental‐Scale Lightning Observations at High Frequency

Geophysical Research Letters, Volume 52, Issue 20, 28 October 2025.
Abstract We initiated high‐frequency (HF, 3–30 MHz) lightning observations to remotely study lightning processes using skywave propagation. HF lightning skywaves were detected at distances up to 3,300 km (potentially farther) during both day and night, with over 64% of events having peak currents below 50 kA.
Yunjiao Pu, Steven A. Cummer, Yongze Jia
wiley   +1 more source

Enhancing Geomagnetic Disturbance Predictions with Neural Networks: A Case Study on K-Index Classification

Atmosphere
To explore the application of neural networks for estimating geomagnetic field disturbances, this study pays particular attention to K-index classification.
Aizhan Altaibek, Beibit Zhumabayev, Aiganym Sarsembayeva, Marat Nurtas, Diana Zakir   +4 more
doaj   +1 more source

VARIATIONS OF IONOSPHERIC PARAMETERS OVER ALMATY (KAZAKHSTAN) IN 1999–2013

Solar-Terrestrial Physics, 2019
The paper presents the results of a study of the behavior of ionospheric parameters of the total electron content, I(t), and electron density in the maximum F2 layer, Nm, over Almaty (Kazakhstan) [43.25° N; 76.92° E] in 1999–2013. The time interval under
Mukasheva S.N., Kapytin V.I., Malimbayev A.M.   +2 more
doaj   +1 more source

Synchronous NmF2 and NmE daytime variations as a key to the mechanism of quiet-time F2-layer disturbances [PDF]

Annales Geophysicae, 2007
The observed NmF2 and NmE variations were analyzed for the periods of positive and negative quiet-time F2-layer disturbances (Q-disturbances) observed in the midlatitude daytime F2-layer to specify the mechanism of their origin. The noontime δNmF2 and
A. V. Mikhailov, V. H. Depuev, A. H. Depueva   +2 more
doaj   +1 more source

Quantifying Electron Precipitation Driven by Chorus Waves Using Self‐Consistent Particle‐In‐Cell Simulations

Geophysical Research Letters, Volume 52, Issue 20, 28 October 2025.
Abstract The precipitation of tens to hundreds of keV electrons from Earth's magnetosphere plays a crucial role in magnetosphere‐ionosphere coupling, primarily driven by chorus wave scattering. Most existing simulations of electron precipitation rely on test particle models that neglect particle feedback on waves.
Huayue Chen, Xueyi Wang, Xiaolei Li, Rui Chen, Lunjin Chen, Yoshiharu Omura, Yi‐Kai Hsieh, Yu Lin, M. L. Adrian   +8 more
wiley   +1 more source

The Substorms of 26 February 2008: A Data‐Mining Perspective

Geophysical Research Letters, Volume 52, Issue 20, 28 October 2025.
Abstract Reconstruction of the magnetospheric magnetic field using swarms of virtual spacecraft provided by data mining confirms seminal in situ evidence (Angelopoulos et al., 2008, https://doi.org/10.1126/science.1160495) that on 26 February 2008 an X‐line emerged in the region between two distant Time History of Events and Macroscale Interactions ...
M. I. Sitnov, G. K. Stephens, T. Motoba, N. A. Tsyganenko   +3 more
wiley   +1 more source

Dependence of the F2-layer critical frequency median at midlatitudes on geomagnetic activity

Solar-Terrestrial Physics, 2017
We put forward a method of separating the geomagnetic activity contribution to the F2-layer critical frequency median, foF2med, at middle latitudes. It is based on the analysis of foF2, which is the ratio foF2med/foF2q in percent, where foF2q is the F2 ...
Deminov M.G., Deminova G.F., Depuev V.Kh., Depueva A.Kh.   +3 more
doaj   +1 more source

KHI Development Between Inner LLBL and Magnetosphere on the Far Flanks as Observed by the MMS Mission

Geophysical Research Letters, Volume 52, Issue 20, 28 October 2025.
Abstract A boundary layer of finite thickness separates the magnetosheath and the magnetosphere. Within this boundary, we have the outer low‐latitude boundary layer (LLBL), the magnetopause current layer, and the inner LLBL. Earlier works point out that the interface on which Kelvin‐Helmholtz Instability (KHI) develops has implications for how ...
Dinesh K. V. Radhakrishnan, Stephen A. Fuselier, Katariina Nykyri, K.‐J. Hwang, Steven M. Petrinec, Daniel J. Gershman, James L. Burch   +6 more
wiley   +1 more source