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Related papers: Inferring the Coronal Density Irregularity from EU…

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An admittedly pedantic but hopefully useful and informative analysis is presented of the EUVE 70--180 Angstrom spectra of nine polars. These spectra are fit with three different models---a blackbody, a pure-H stellar atmosphere, and a solar…

Astrophysics · Physics 2007-05-23 Christopher W. Mauche

Following previous investigations by Giordano and Mancuso [1] and Mancuso and Giordano [2, 3] on the differential rotation of the solar corona as obtained through the analysis of the intensity time series of the O VI 1032 Ang. spectral line…

Solar and Stellar Astrophysics · Physics 2012-11-16 Salvatore Mancuso , Silvio Giordano

Treatments of the radio scattering due to density turbulence in the solar wind typically employ asymptotic approximations to the phase structure function. We use a general structure function (GSF) that straddles the asymptotic limits and…

Solar and Stellar Astrophysics · Physics 2015-09-28 Madhusudan Ingale

Spectroscopic diagnostics of solar coronal plasmas critically depends on the uncertainty in the measured line intensities. One of the main sources of uncertainty is instrumental scattered light, which is potentially most important in…

Solar and Stellar Astrophysics · Physics 2018-04-04 Carolyn Wendeln , Enrico Landi

The variability of helium abundance in the solar corona and the solar wind is an important signature of solar activity, solar cycle, solar wind sources, as well as coronal heating processes. Motivated by recently reported remote sensing UV…

Solar and Stellar Astrophysics · Physics 2024-06-24 Leon Ofman , Yogesh , Silvio Giordano

A comparison between a Coronal Hole (CH) and the adjacent Quiet-Sun (QS) has been performed using spectroscopic diagnostics of Hinode/ the EUV Imaging Spectrometer (EIS). Coronal funnels play an important role in the formation and…

Solar and Stellar Astrophysics · Physics 2015-11-04 P. Kayshap , D. Banerjee , A. K. Srivastava

We present an analysis of small-scale, periodic, solar-wind density enhancements (length-scales as small as \approx 1000 Mm) observed in images from the Heliospheric Imager (HI) aboard STEREO A. We discuss their possible relationship to…

Solar and Stellar Astrophysics · Physics 2010-09-30 Nicholeen M. Viall , Harlan E. Spence , Angelos Vourlidas , Russell Howard

We develop a reliable, fully automatic method for the detection of coronal holes, that provides consistent full-disk segmentation maps over the full solar cycle and can perform in real-time. We use a convolutional neural network to identify…

Solar and Stellar Astrophysics · Physics 2021-08-09 R. Jarolim , A. M. Veronig , S. Hofmeister , S. G. Heinemann , M. Temmer , T. Podladchikova , K. Dissauer

A new dataset of summed neutral N2 and O number density profiles, spanning altitudes between 150 and 400 km, and observed during Northern Winter from 2010 through 2016 is presented. The neutral density profiles are derived from solar…

Earth and Planetary Astrophysics · Physics 2018-02-14 E. M. B. Thiemann , M. Dominique , M. D. Pilinski , F. G. Eparvier

We estimate the coronal density of Capella using the O VII and Fe XVII line systems in the soft X-ray regime that have been observed over the course of the Chandra mission. Our analysis combines measures of error due to uncertainty in the…

Solar and Stellar Astrophysics · Physics 2024-06-21 Xixi Yu , Vinay L. Kashyap , Giulio Del Zanna , David A. van Dyk , David C. Stenning , Connor P. Ballance , Harry P. Warren

We present spectral synthesis calculations of the solar extreme UV (EUV) in spherical symmetry carried out with the 'Solar Modeling in 3D' code. The calculations are based on one-dimensional atmospheric structures that represent a temporal…

Solar and Stellar Astrophysics · Physics 2015-05-27 Margit Haberreiter

We aim to reproduce the structure of the corona above a solar active region as seen in the extreme ultraviolet (EUV) using a three-dimensional magnetohydrodynamic (3D MHD) model. The 3D MHD data-driven model solves the induction equation…

Solar and Stellar Astrophysics · Physics 2019-04-30 Jörn Warnecke , Hardi Peter

The quiet-Sun coronal electron-temperature ratio $R \equiv T_\mathrm{EUV}/T_B \approx 2.4$, stable across an eight-year solar cycle, is read here as a measurement of relative entropy between two diagnostic projections of the coronal…

Solar and Stellar Astrophysics · Physics 2026-04-28 V. Edmonds

Solar flare electron acceleration is an efficient process, but its properties (mechanism, location) are not well constrained. Via hard X-ray (HXR) emission, we routinely observe energetic electrons at the Sun, and sometimes we detect…

Solar and Stellar Astrophysics · Physics 2023-10-09 Ross Pallister , Natasha L. S. Jeffrey

Using 12CO and 13CO observations we present column density maps of the molecular cloud (V = -135 km/s) in the direction of 1E1740.7-2942. Hydrogen column densities of the cloud scatter between (3.5 - 11) 10**22 cm-2, depending on the method…

Astrophysics · Physics 2007-05-23 O. Vilhu , D. Hannikainen , P. Muhli , J. Huovelin , J. Poutanen , Ph. Durouchoux , P. Wallyn

Using wavelet analysis approach, we can derive a measure of the disorder content of solar activity, following the temporal evolution of the so-called wavelet entropy. The interesting feature of this parameter is its ability to extract a…

Astrophysics · Physics 2015-06-24 Stefano Sello

The solar corona is full of dynamic phenomena, e.g., solar flares, micro flares in active regions, jets in coronal holes and in the polar regions, X-ray bright points in quiet regions, etc. They are accompanied by interesting physical…

Solar and Stellar Astrophysics · Physics 2017-06-15 Noriyuki Narukage , Shin-nosuke Ishikawa , Tomoko Kawate , Shinsuke Imada , Taro Sakao

On 2008 January 10, the twin Solar Terrestrial Relations Observatory (STEREO) A and B spacecraft conducted a high time cadence study of the solar corona with the Extreme UltraViolet Imager (EUVI) instruments with the aim of investigating…

Solar and Stellar Astrophysics · Physics 2010-01-15 M. S. Marsh , R. W. Walsh , S. Plunkett

The spatial-temporal evolution of coronal plasma parameters of the solar outer atmosphere at global scales, derived from solar full-disk imaging spectroscopic observation in the extreme-ultraviolet band, is critical for understanding and…

Solar and Stellar Astrophysics · Physics 2024-10-23 Yufei Feng , Xianyong Bai , Sifan Guo , Hui Tian , Lami Chan , Yuanyong Deng , Qi Yang , Wei Duan , Xiaoming Zhu , Xiao Yang , Zhiwei Feng , Zhiyong Zhang

We review novel data analysis techniques developed or adapted for the field of coronal seismology. We focus on methods from the last ten years that were developed for extreme ultraviolet (EUV) imaging observations of the solar corona, as…

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