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Solar rotational tomography (SRT) applied to white-light coronal images observed at multiple aspect angles has been the preferred approach for determining the three-dimensional (3D) electron density structure of the solar corona. However,…

Solar and Stellar Astrophysics · Physics 2016-10-04 Didier Vibert , Christelle Peillon , Philippe Lamy , Richard A. Frazin , Julien Wojak

We observed the coronally active eclipsing binary, AR Lac, with the High Energy Transmission Grating on Chandra for a total of 97 ks, spaced over five orbits, at quadratures and conjunctions. Contemporaneous and simultaneous EUV spectra and…

A major challenge in solar physics is to obtain empirical information on the magnetic field of the million-degree plasma of the solar corona. To this end, we need observables of the solar radiation sensitive to the coronal magnetic field.…

We report first results from an ongoing program of combining visibilities from the Giant Meterwave Radio Telescope (GMRT) and the Nancay Radio Heliograph (NRH) to produce composite snapshot images of the sun at meter wavelengths. We…

New and advanced space-based observing facilities continue to lower the resolution limit and detect solar coronal loops in greater detail. We continue to discover even finer sub-structures within coronal loop cross sections, in order to…

Solar and Stellar Astrophysics · Physics 2015-06-22 Eamon Scullion , Luc Rouppe van der Voort , Sven Wedemeyer , Patrick Antolin

Estimating the magnetic field strength in the solar corona is crucial for understanding different physical processes happening over diverse spatio-temporal scales. However, the high temperatures and low density of the solar corona make this…

Solar and Stellar Astrophysics · Physics 2024-03-07 Upasna Baweja , Vaibhav Pant , Iñigo Arregui

The Wide-field Imager for Solar Probe (WISPR) onboard Parker Solar Probe (PSP), observing in white light, has a fixed angular field of view, extending from 13.5 degree to 108 degree from the Sun and approximately 50 degree in the transverse…

Solar and Stellar Astrophysics · Physics 2022-10-12 P. C. Liewer , J. Qiu , F. Ark , P. Penteado , G. Stenborg , A. Vourlidas , J. R. Hall , P. Riley

Coronal density, temperature and heat flux distributions for the equatorial and polar corona have been deduced by Lemaire [2012] from Saito's model of averaged coronal white light (WL) brightness and polarization observations. They are…

Solar and Stellar Astrophysics · Physics 2015-06-05 V. Pierrard , K. Borremans , J. F. Lemaire

For the first time, we have used RHESSI's spatial and energy resolution to determine the combined chromospheric and coronal density profile of the flaring solar atmosphere in a statistical manner, using a dataset of 838 flares observable in…

Solar and Stellar Astrophysics · Physics 2015-06-03 Pascal Saint-Hilaire , Sam Krucker , Robert P. Lin

The Airborne Infrared Spectrometer (AIR-Spec) was commissioned during the 2017 total solar eclipse, when it observed five infrared coronal emission lines from a Gulfstream V (GV) research jet owned by the National Science Foundation (NSF)…

Solar and Stellar Astrophysics · Physics 2022-07-20 Jenna E. Samra , Chad A. Madsen , Peter Cheimets , Edward E. DeLuca , Leon Golub , Vanessa Marquez , Naylynn Tañón Reyes

SECIS observations of the June 2001 total solar eclipse were taken using an Fe xiv 5303 A filter. Existing software was modified and new code was developed for the reduction and analysis of these data. The observations, data reduction,…

A new source in solar corona scattering photospheric and chromospheric Fraunhofer spectral lines is detected below a height of one solar radius above solar limb, consisting of tenuous and cool neutral atoms and much fewer once ionized ions.…

Solar and Stellar Astrophysics · Physics 2025-12-24 Z. Q. Qu , R. Y. Zhou , H. Su , Y. Liang

Potential Field Source Surface (PFSS) models are widely used to simulate coronal magnetic fields. PFSS models use the observed photospheric magnetic field as the inner boundary condition and assume a perfectly radial field beyond a ``Source…

Solar and Stellar Astrophysics · Physics 2024-08-30 Luke Fushimi Benavitz , Benjamin Boe , Shadia Rifai Habbal

It is argued that depolarization of solar radio bursts requires reflection off boundary layers no thicker than about a wavelength (a few meters at most) between regions with large density ratios. The implied inhomogeneities suggest that the…

Astrophysics · Physics 2009-11-13 D. B Melrose

Based on energetic particle observations made at $\approx$1 AU, we present a catalogue of 46 wide-longitude (>45{\deg}) solar energetic particle (SEP) events detected at multiple locations during 2009-2016. The particle kinetic energies of…

The spectra of coronal mass ejections (CMEs) in the low corona play a crucial role in understanding their origins and physical mechanism, and enhancing space weather forecasting. However, capturing these spectra faces significant…

Solar and Stellar Astrophysics · Physics 2025-04-01 Lami Chan , Xianyong Bai , Hui Tian , Yufei Feng , Yu Xu , Tibor Török , Yuhang Gao , Tanmoy Samanta , Zheng Sun

One of the mechanisms proposed for heating the corona above solar active regions is the damping of magnetohydrodynamic (MHD) waves. Continuing on previous work, we provide observational evidence for the existence of high-frequency MHD waves…

We present results from the first solar full-disk F$_{10.7}$ (the radio flux at $10.7$ cm, $2.8$ GHz) image taken with the S-band receivers on the recently upgraded Karl G. Jansky Very Large Array (VLA) in order to assess the relationship…

Solar and Stellar Astrophysics · Physics 2015-08-05 S. J. Schonfeld , S. M. White , C. J. Henney , C. N. Arge , R. T. J. McAteer

Since the Lalpha rocket observations of (Gabriel, Solar Phys. 21, 392, 1971), it has been realized that the hydrogen (H) lines could be observed in the corona and offer an interesting diagnostic for the temperature, density, and radial…

Solar and Stellar Astrophysics · Physics 2016-11-15 Jean-Claude Vial , Martine Chane-Yook