Results 61 to 70 of about 2,361 (168)
Extreme ultraviolet emission lines of Ni xii in laboratory and solar spectra [PDF]
, 2004 A linear force-free field solution is presented in cylindrical coordinates, formulated in terms of trigonometric and Bessel functions. A numerical exploration has revealed that this solution describes magnetic field lines that meander in Cartesian space, as well as field lines that lie on toroidal flux surfaces.
Botha, Gert, Evangelidis, E. A.
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The Link between Nonthermal Velocity and Free Magnetic Energy in Solar Flares
The Astrophysical Journal LettersThe cause of excess spectral line broadening (nonthermal velocity) is not definitively known, but given its rise before and during flaring, the causal processes hold clues to understanding the triggers for the onset of reconnection and the release of ...
James McKevitt +7 more
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Modeling of the Extreme‐Ultraviolet and Soft X‐Ray Emission in a Solar Coronal Bright Point
The Astrophysical Journal, 2008 Previous studies have been able to reproduce both the observed intensities and the morphology of high-temperature solar plasma using steady state heating models. These models, however, have been unable to reproduce the lower temperature emission observed in active regions. Here we present results from numerical simulations of a coronal bright point. We
David H. Brooks, Harry P. Warren
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The Extreme-ultraviolet Precursors and Postcursors of Solar Flares
The Astrophysical JournalEUV brightenings are small-scale magnetic reconnection events that consistently appear before and after solar flares. However, it is not well understood how EUV precursors might foreshadow flares and what the physical connection is between the EUV ...
Larisza D. Krista
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Extreme‐Ultraviolet Emission Lines of S
The Astrophysical Journal, 2002 New -matrix calculations of electron impact excitation rates for transitions among the 2s22p, 2s2p2 and 2p3 levels of S XII are presented. These data are subsequently used to derive the theoretical electron density diagnostic emission line intensity ratios R1 = I(215.16 A)/I(299.50 A), R2 = I(218.19 A)/I(299.50 A), R3 = I(288.40 A)/I(299.50 A), and R4 =
Keenan, Francis +6 more
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Evolution of Flare Ribbon Bead-like Structures in a Solar Flare
The Astrophysical Journal LettersWe present fast-cadence and high-resolution observations of flare ribbons from the Solar Orbiter Extreme Ultraviolet Imager (EUI). Utilizing the short-exposure observations from the EUI High Resolution Imager in the extreme-ultraviolet, we find small ...
Ryan J. French +8 more
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The Astrophysical Journal LettersThe apparent slipping motion of flare loops is regarded as a key feature of the 3D magnetic reconnection in the solar flares. The slippage with a super-Alfvénic speed could be defined as slipping–running reconnection, while the slippage with a sub ...
Yining Zhang +5 more
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The Astrophysical JournalQuasiperiodic oscillations in solar-flaring emission have been observed over the past few decades. To date, the underpinning processes resulting in the quasiperiodic oscillations remain unknown.
Yining Zhang, Ting Li, Jing Ye
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Solar Atmospheric Oscillations as Measured by the GOES-R Series EXIS EUVS-C Instrument
The Astrophysical Journal LettersThis Letter presents first observations of distinct solar atmospheric oscillations from signals collected by the Extreme Ultraviolet and X-ray Irradiance Sensors EUVS-C instrument, which is part of each Geostationary Observational Environmental Satellite
Thomas D. Eden Jr. +6 more
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A Semiempirical Estimate of Solar Extreme-ultraviolet Evolution from 10 Myr to 10 Gyr
The Astronomical JournalThe extreme-ultraviolet (EUV; 100–911 Å) spectra of F, G, K, and M stars provide diagnostics of the stellar chromosphere through the corona, with line and continuum formation temperatures spanning roughly 10 ^4 –10 ^7 K.
Kevin France +11 more
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