Results 41 to 50 of about 1,272,533 (187)

Propagation Dynamics of Fast Electron Beam and Its Electron Cyclotron Maser Emission

Journal of Geophysical Research: Space Physics, Volume 131, Issue 10, October 2026.
Abstract Fast electron beams (FEBs) and coherent radio bursts both are very common plasma activity phenomena in the cosmos. The electron cyclotron maser (ECM) instability driven by FEBs trapped in magnetic fields can directly amplify radio wave radiations.
Ling Chen, Dejin Wu, Jianfei Tang, Guoqing Zhao   +3 more
wiley   +1 more source

New Insights into Type-I Solar Noise Storms from High Angular Resolution Spectroscopic Imaging with the Upgraded Giant Metrewave Radio Telescope

The Astrophysical Journal
Type-I solar noise storms are perhaps the most commonly observed active radio emissions from the Sun at meter-wavelengths. Noise storms have a long-lived and wideband continuum background with superposed islands of much brighter narrowband and short ...
Surajit Mondal, Devojyoti Kansabanik, Divya Oberoi, Soham Dey   +3 more
doaj   +1 more source

Modeling the Daily Variations of the Coronal X-ray Spectral Irradiance with Two Temperatures and Two Emission Measures

The Astrophysical Journal, 2023
The Miniature X-ray Solar Spectrometer (MinXSS-1) CubeSat observed solar X-rays between 0.5 and 10 keV. A two-temperature, two-emission-measure model is fit to each daily averaged spectrum.
Bennet D. Schwab, Thomas N. Woods, James Paul Mason   +2 more
doaj   +1 more source

An Operational Daily‐Filtered Dominion Radio Astrophysical Observatory F10.7 cm Solar Radio Flux Product

Earth and Space Science, Volume 13, Issue 9, September 2026.
Abstract The F10.7 solar radio flux density, or F10.7, is a disk‐integrated measure of the Sun's total emission at 10.7 cm (2.8 GHz) and is a widely‐used proxy of solar activity. F10.7 emissions primarily originate from the Sun's upper chromosphere and lower corona. High‐frequency, transient “radio bursts” can dramatically increase the magnitude of F10.
C. Kuester, O. M. Coddington, C. Lindholm, C. L. Peck   +3 more
wiley   +1 more source

A Statistical Survey of Faint Solar X-Ray Transients Observed by NuSTAR

The Astrophysical Journal
In this paper, we use a highly sensitive telescope to characterize solar X-ray transients ranging from microflares in active regions down to weakly energetic brightenings in the quiet Sun.
Reed B. Masek, Lindsay Glesener, Jessie Duncan, Kekoa Lasko, Natália Bajnoková, Mary Davenport, Marianne Peterson, Ian Markano, Zasha Avery, Kristopher Cooper, Iain G. Hannah, Brian W. Grefenstette, Stephen M. White, Hugh Hudson, Säm Krucker, David M. Smith, Sarah Paterson   +16 more
doaj   +1 more source

Automated coronal hole identification via multi-thermal intensity segmentation

Journal of Space Weather and Space Climate, 2018
Coronal holes (CH) are regions of open magnetic fields that appear as dark areas in the solar corona due to their low density and temperature compared to the surrounding quiet corona.
Garton Tadhg M., Gallagher Peter T., Murray Sophie A.   +2 more
doaj   +1 more source

Is There a High‐Energy Particle Population in the Quiet Solar Corona?

The Astrophysical Journal, 2007
A study of spectra emitted by the quiet solar corona indicates that the majority of line intensities originating in low-lying levels are consistent with isothermal plasma of ~1.3 × 106 K. Nevertheless, a number of line intensities and, in particular, those belonging to ions that are typical of higher temperatures are brighter than expected.
Yu. Ralchenko, U. Feldman, G. A. Doschek
openaire   +1 more source

Predicting Geomagnetic Activity in the Ascending and Declining Phases of the Solar Cycle

Space Weather, Volume 24, Issue 8, August 2026.
Abstract Most predictions of space climate, that is, the long‐term behavior of the solar‐terrestrial environment, have focused on forecasting the 11‐year sunspot cycle. Geomagnetic activity, on the other hand, has mainly been predicted in shorter, space weather timescales of up to days to weeks.
Timo Qvick, Timo Asikainen, Kalevi Mursula   +2 more
wiley   +1 more source

Unraveling the Fine‐Scale Tapestry of Solar Wind at 1AU

Geophysical Research Letters, Volume 53, Issue 13, 16 July 2026.
Abstract Solar wind is a complex network of distinct magnetic flux tubes, each contained and separated by a current sheet. In this study, more than 50,000 current sheets in the solar wind are identified and characterized for the first time, using multi‐point Cluster observations during solar minimum and maximum intervals.
M. Akhavan‐Tafti, S. Kumar, A. Szabo, B. Grison   +3 more
wiley   +1 more source

Low‐Frequency Radio Observations of the “Quiet” Corona During the Descending Phase of Sunspot Cycle 24 [PDF]

, 2020
We carried out a statistical study of the "quiet" solar corona during the descending phase of the Sunspot Cycle 24 (i.e., January 2015 to May 2019) using data obtained with the Gauribidanur RAdioheliograPH (GRAPH) at 53 and 80 MHz simultaneously.
R. Ramesh, D. Ketaki, M. Vrunda, A. Kumari, Rajesh, M., M. Rajesh, Ketaki, D., Ramesh, R., C. Kathiravan, Kumari, A., Vrunda, M., Kathiravan, C.   +11 more
core   +1 more source