Results 71 to 80 of about 109,561 (153)

Magnetically Quiet‐Time Traveling Ionospheric Disturbances Over Mid‐Latitude Eastern Europe Observed by the Kharkiv Incoherent Scatter Radar During the 24th Solar Cycle

Journal of Geophysical Research: Space Physics, Volume 130, Issue 4, April 2025.
Abstract We have detected and characterize traveling ionospheric disturbances (TIDs) in the mid‐latitude ionosphere over Europe using data from the Kharkiv incoherent scatter (IS) radar. The study focused on observations near solstices and equinoxes during solar cycle 24 under magnetically quiet conditions.
Kateryna D. Aksonova, Sergii V. Panasenko, Dalia Buresova, Larisa P. Goncharenko, Shun‐Rong Zhang, Igor F. Domnin   +5 more
wiley   +1 more source

A Peculiar Feature of the First Ionization Potential Effect Before a Solar Flare Impulsive Phase Observed by MSS-1B, CHASE, and SDO

The Astrophysical Journal
The impulsive phase of solar flares is often accompanied by the depletion of the elements with low first ionization potential (FIP), whose abundance decreases from the coronal level to the photospheric level, and then recovers back to the coronal level ...
Man-Hei Ng, Xiaoping Zhang, P. F. Chen
doaj   +1 more source

Observation of a reversal of rotation in a sunspot during a solar flare

Nature Communications, 2016
Back reaction of coronal magnetic fields on the solar surface may help to understand the coronal reconfiguration during a solar flare. Here the authors report observation of reversal of the rotation of a sunspot during a X1.6 flare with data from HMI.
Yi Bi, Yunchun Jiang, Jiayan Yang, Junchao Hong, Haidong Li, Bo Yang, Zhe Xu   +6 more
doaj   +1 more source

The Relationship Between EUV Nonthermal Line Broadening and High-energy Particle During Solar Flare [PDF]

, 2013
We have studied the relationship between the location of EUV nonthermal broadening and high-energy particles during the large flares by using EUV imaging spectrometer onboard {\it Hinode}, Nobeyama Radio Polarimeter, Nobeyama Radioheliograph, and Atmospheric Imaging Assembly onboard {\it Solar Dynamic Observatory}. We have analyzed the five large flare
arxiv   +1 more source

Ionospheric D Region: Characteristics Near Dawn and Dusk

Journal of Geophysical Research: Space Physics, Volume 130, Issue 4, April 2025.
Abstract The characteristics of very low frequency (VLF) radio wave propagation in the Earth‐ionosphere waveguide are determined particularly through dawn and dusk using phase and amplitude measurements of man‐made signals propagating below the ionospheric D region. For the first time variations of “Wait” height and sharpness parameters, H' and β, have
Neil R. Thomson, Mark A. Clilverd, Craig J. Rodger   +2 more
wiley   +1 more source

Initial Observations of Sunspot Oscillations Excited by Solar Flare [PDF]

, 2007
Observations of a large solar flare of December 13, 2006, using Solar Optical Telescope (SOT) on Hinode spacecraft revealed high-frequency oscillations excited by the flare in the sunspot chromosphere. These oscillations are observed in the region of strong magnetic field of the sunspot umbra, and may provide a new diagnostic tool for probing the ...
arxiv   +1 more source

Helium in Mercury's Extended Exosphere Determined by Pick‐Up Generated Ion Cyclotron Waves

Journal of Geophysical Research: Planets, Volume 130, Issue 4, April 2025.
Abstract Helium (He) was first detected by remote spectroscopic observations of the Ultraviolet Visible Spectrometers (UVVS) instrument in Mercury's exosphere during the three Mariner 10 flybys in 1974 and 1975. Here, we derive the first in situ radial density profile of He in Mercury's extended exosphere by analyzing magnetic field and plasma ...
F. Weichbold, H. Lammer, D. Schmid, M. Volwerk, J. Hener, A. Varsani, A. Vorburger, P. Wurz, C. Simon‐Wedlund   +8 more
wiley   +1 more source

Correlation Between the Delay and Rise Time of VLF/LF Amplitudes During 20 Solar X‐Ray Flares Observed in February 2014 at Mid‐Latitude

Radio Science, Volume 60, Issue 4, April 2025.
Abstract During daylight hours, the concentration of electrons in the ionosphere can be amplified by solar flares, which may subsequently influence the propagation of radio waves. Previous research on Very Low Frequency (VLF) signals focused on X‐class and M‐class flares.
Y. Liu, M. Füllekrug
wiley   +1 more source

Observations of Geomagnetic Crochet at High‐Latitudes Due To X1.5 Class Solar Flare on 3 July 2021

Space Weather
On 3 July 2021, an X1.5 solar flare from the National Oceanic and Atmospheric Administration solar Active Region AR12838 (24°N, 88°W) occurred at 14:18 UT, peaked at 14:29 UT, and decayed at 14:34 UT. The study of this X1.5 solar flare is significant due
S. S. Rao, Nandita Srivastava, Monti Chakraborty, Sandeep Kumar, D. Chakrabarty   +4 more
doaj   +1 more source

The Magnetosphere‐Ionosphere‐Ground Responses to the May 2024 Super Solar Storm

Space Weather, Volume 23, Issue 4, April 2025.
Abstract Earth suffered the attack of the strongest geomagnetic storm in the last 20 years (Kp = 9, Dst∼ ${\sim} $ −400 nT) occurred on 11 May 2024. Taking advantage of the LEO multi‐parameter CSES satellite (launched in 2018) with a large inclination angle 97° $97{}^{\circ}$, with the joint observations of NOAA and GOES, we present a comprehensive ...
Zhenxia Zhang, Fang Zhang, Lu Wang, Xinqiao Li, Zeren Zhima, Yongfu Wang, Yanyan Yang, Dehe Yang, Shujie Li, Wei Chu, Na Zhou, Dedong Wang, Dali Zhang, Roberto Battiston, Roberto Iuppa, Xuhui Shen   +15 more
wiley   +1 more source