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Tomography of the solar corona can provide cruicial constraints for models of the low corona, unique information on changes in coronal structure and rotation rates, and a valuable boundary condition for models of the heliospheric solar…

Instrumentation and Methods for Astrophysics · Physics 2015-09-11 Huw Morgan

A differential emission measure (DEM) method is used to evaluate the relationship of the electron density and temperature before and after a coronal rain event during an active sun over the period from 20:10 UT on October 6 to 02:10 on…

Solar and Stellar Astrophysics · Physics 2021-10-05 Z. M. Vashalomidze , T. V. Zaqarashvili , V. D. Kukhianidze

Analysis of the solar coronal green line profiles reveals information regarding the physical conditions of the solar corona like temperature, density, Doppler velocity, non-thermal velocity etc. It provides insights to the unresolved…

Solar and Stellar Astrophysics · Physics 2013-07-02 Maya Prabhakar , K. P. Raju , T. Chandrasekhar

Understanding the physical processes responsible for accelerating the solar wind requires detailed measurements of the collisionless plasma in the extended solar corona. Some key clues about these processes have come from instruments that…

The critical need to study the magnetic field in the solar corona is highlighted by recent observational facilities, such as DKIST and Aditya-L1. A powerful tool for probing the magnetism of the solar corona is forward modeling of the…

Coronal loops serve as the fundamental building blocks of the solar corona. Therefore, comprehending their properties is essential in unraveling the dynamics of the Sun's upper atmosphere. In this study, we conduct a comparative analysis of…

The EUV (100-912 {\AA}) is a spectral region notoriously difficult to observe due to attenuation by neutral hydrogen gas in the interstellar medium. Despite this, hundreds to thousands of nearby stars of different spectral types and…

Solar corona is much hotter than lower layers of the solar atmosphere-photosphere and chromosphere. The coronal temperature is up to 1MK in quiet sun areas, while up to several MK in active regions, which implies a key role of magnetic…

Solar and Stellar Astrophysics · Physics 2025-06-24 Gregory D. Fleishman , Alexey A. Kuznetsov , Gelu M. Nita

Accurate forecasting of the solar wind has grown in importance as society becomes increasingly dependent on technology that is susceptible to space weather events. This work describes an inner boundary condition for ambient solar wind…

Space Physics · Physics 2022-07-22 Kaine A. Bunting , Huw Morgan

We present coronal density profiles derived from low-frequency (80-240 MHz) imaging of three type III solar radio bursts observed at the limb by the Murchison Widefield Array (MWA). Each event is associated with a white light streamer at…

Solar and Stellar Astrophysics · Physics 2018-10-17 Patrick I. McCauley , Iver H. Cairns , John Morgan

Extreme ultraviolet (EUV) coronal dimmings are often observed in response to solar eruptive events. These phenomena can be generated via several different physical processes. For space weather, the most important of these is the temporary…

Solar and Stellar Astrophysics · Physics 2016-10-12 James Paul Mason , Thomas N. Woods , David F. Webb , Barbara J. Thompson , Robin C. Colaninno , Angelos Vourlidas

Using Hinode EUV Imaging Spectrometer (EIS) spectra recorded daily at Sun center from the end of 2006 to early 2011, we studied the long-term evolution of the quiet corona. The light curves of the higher temperature emission lines exhibit…

Solar and Stellar Astrophysics · Physics 2012-07-17 S. Kamio , J. T. Mariska

We present a study of the differential emission measure (DEM) of a `quiet Sun' area observed in the extreme ultraviolet at normal incidence by the Coronal Diagnostic Spectrometer (CDS) on the SOHO spacecraft. The data used for this work…

Astrophysics · Physics 2009-11-10 A. C. Lanzafame , D. H. Brooks , J. Lang

We study extreme-ultraviolet emission line spectra derived from three-dimensional magnetohydrodynamic models of structures in the corona. In order to investigate the effects of increased magnetic activity at photospheric levels in a…

Solar and Stellar Astrophysics · Physics 2009-04-16 Pia Zacharias , Sven Bingert , Hardi Peter

We present a Differential Emission Measure (DEM) analysis of the quiet solar corona on disk using data obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on {\it Hinode}. We show that the expected quiet Sun DEM distribution can…

Solar and Stellar Astrophysics · Physics 2009-11-09 David H. Brooks , Harry P. Warren , David R. Williams , Tetsuya Watanabe

Both remote-sensing measurements using the interplanetary scintillation (IPS) technique and in situ measurements by the Ulysses spacecraft show a bimodal structure for the solar wind at solar minimum conditions. At present what makes the…

Solar and Stellar Astrophysics · Physics 2015-05-27 Bo Li , Li-Dong Xia , Yao Chen

Recent solar spectroscopic observations have shown that coronal spectral lines can exhibit asymmetric profiles, with enhanced emissions at their blue wings. These asymmetries correspond to rapidly upflowing plasmas at speeds exceeding ~ 50…

Solar and Stellar Astrophysics · Physics 2015-06-18 Spiros Patsourakos , James Klimchuk , Peter Young

The goal of this paper is to apply statistical methods to determine electrons densities and their errors from measurements of density-sensitive line intensities in the quiet Sun. Three methods are employed. The first is the use of…

Solar and Stellar Astrophysics · Physics 2020-06-17 Kenneth Dere

It was recently proposed that the intensity ratios of several extreme ultraviolet spectral lines from the Fe X ion can be used to measure the solar coronal magnetic field based on the magnetic-field-inducedtransition (MIT) theory. To verify…

Solar and Stellar Astrophysics · Physics 2021-10-27 Yajie Chen , Wenxian Li , Hui Tian , Feng Chen , Xianyong Bai , Yang Yang , Zihao Yang , Xianyu Liu , Yuanyong Deng

Properties of the Sun's interior can be determined accurately from helioseismological measurements of solar oscillations. These measurements, however, are in conflict with photospheric elemental abundances derived using 3-D hydrodynamic…

Solar and Stellar Astrophysics · Physics 2018-07-18 David H. Brooks , Deborah Baker , Lidia van Driel-Gesztelyi , Harry P. Warren