Results 51 to 60 of about 1,202,560 (191)

The propagation and damping of slow magnetoacoustic waves in the solar atmosphere [PDF]

open access: yes, 2012
The propagation and damping of slow magnetoacoustic waves in the solar atmosphere is investigated, with particular emphasis placed on waves with periodicities of five minutes. The basic model of a uniform temperature loop is extended by the addition of
Owen, Nicholas Robert
core   +2 more sources

Hinode/EIS Observation of the Alfvénic Fluctuations in the Quiet Sun

open access: yesThe Astrophysical Journal
Alfvénic fluctuations in the corona are regularly observed in EUV imaging and infrared spectroscopic data. We report here on the Doppler velocity fluctuations within the data from the Extreme-Ultraviolet Imaging Spectrometer (EIS) on board Hinode.
Edris Tajfirouze   +2 more
doaj   +1 more source

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

open access: yesSpace 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   +2 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

open access: yesThe 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   +3 more
doaj   +1 more source

Automated coronal hole identification via multi-thermal intensity segmentation

open access: yesJournal 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.   +2 more
doaj   +1 more source

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

open access: yesGeophysical 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   +3 more
wiley   +1 more source

The investigation of quasi-separatrix layers in solar magnetic fields [PDF]

open access: yes, 2011
The structure of the magnetic field is often an important factor in many energetic processes in the solar corona. To determine the topology of the magnetic field features such as null points, separatrix surfaces, and separators must be found.
Restante, Anna Lisa
core   +2 more sources

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

open access: yesThe 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

Terrestrial Gamma‐Ray Flash Following Intense Negative Return Stroke Observed With BIMAP‐3D

open access: yesJournal of Geophysical Research: Atmospheres, Volume 131, Issue 13, 16 July 2026.
Abstract We report ground‐based observations of a terrestrial gamma‐ray flash (TGF) associated with a strong negative cloud‐to‐ground lightning strike (‐CG) which occurred near Los Alamos National Laboratory (LANL) in New Mexico, USA. Gamma photons were detected by the Terrestrial High‐energy Observations of Radiation (THOR) instrument, developed at ...
Daniel P. Jensen   +4 more
wiley   +1 more source

Estimating Electron Densities in the Middle Solar Corona Using White-light and Radio Observations

open access: yesThe Astrophysical Journal
The electron density of the solar corona is a fundamental parameter in many areas of solar physics. Traditionally, routine estimates of coronal density have relied exclusively on white-light observations.
Surajit Mondal   +48 more
doaj   +1 more source

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