Results 71 to 80 of about 112,475 (200)

Early Abnormal Temperature Structure of X-ray Looptop Source of Solar Flares [PDF]

, 2008
This Letter is to investigate the physics of a newly discovered phenomenon -- contracting flare loops in the early phase of solar flares. In classical flare models, which were constructed based on the phenomenon of expansion of flare loops, an energy releasing site is put above flare loops.
arxiv   +1 more source

The Magnetic Topology of AR13664 Leading to Its First Halo CME

Journal of Geophysical Research: Space Physics, Volume 130, Issue 4, April 2025.
Abstract In the first half of May 2024, the solar active region (AR) NOAA 13664 was responsible for generating the strongest geomagnetic storm in over 20 years through an enhanced production of coronal mass ejections (CMEs). A key factor in this production was the complex magnetic topology of AR13664.
D. MacTaggart, T. Williams, O. P. M. Aslam   +2 more
wiley   +1 more source

The Shape of M Dwarf Flares in Kepler Light Curves [PDF]

, 2015
Ultra-precise light curves from Kepler provide the best opportunity to determine rates and statistical properties of stellar flares. From 11 months of data on the active M4 dwarf, GJ 1243, we have built the largest catalog of flares for a single star: over 6100 events.
arxiv   +1 more source

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

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

A Joint Microwave and Hard X-Ray Study toward Understanding the Transport of Accelerated Electrons During an Eruptive Solar Flare

The Astrophysical Journal
The standard flare model, despite its success, is limited in comprehensively explaining the various processes involving nonthermal particles. One such missing ingredient is a detailed understanding of the various processes involved during the transport ...
Surajit Mondal, Andrea F. Battaglia, Bin Chen, Sijie Yu   +3 more
doaj   +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

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

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