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Recent spectroscopic observations have revealed the ubiquitous presence of blueward asymmetries of emission lines formed in the solar corona and transition region. These asymmetries are most prominent in loop footpoint regions, where a…

Solar and Stellar Astrophysics · Physics 2011-08-11 Hui Tian , Scott W. McIntosh , Bart De Pontieu , Juan Martinez-Sykora , Marybeth Sechler , Xin Wang

Coronal Bright Points (CBPs) are ubiquitous structures in the solar atmosphere composed of hot small-scale loops observed in EUV or X-Rays in the quiet Sun and coronal holes. They are key elements to understand the heating of the corona;…

Solar and Stellar Astrophysics · Physics 2022-08-24 D. Nóbrega-Siverio , F. Moreno-Insertis

Source imaging of solar radio bursts can be used to track energetic electrons and associated magnetic structures. Here we present a combined analysis of data at different wavelengths for an eruption associated with a moving type-IV (t-IVm)…

Solar and Stellar Astrophysics · Physics 2019-01-09 V. Vasanth , Yao Chen , Maoshui Lv , Hao Ning , Chuangyang Li , Shiwei Feng , Zhao Wu , Guohui Du

A forward model is described in which we synthesize spectra from an ab-initio 3D MHD simulation of an outer stellar atmosphere, where the coronal heating is based on braiding of magnetic flux due to photospheric footpoint motions. We…

Astrophysics · Physics 2009-11-10 H. Peter , B. V. Gudiksen , A. Nordlund

Global extreme ultraviolet (EUV) waves are spectacular traveling disturbances in the solar corona associated with energetic eruptions such as coronal mass ejections (CMEs) and flares. Over the past 15 years, observations from three…

Solar and Stellar Astrophysics · Physics 2014-05-07 Wei Liu , Leon Ofman

Observing the Sun at high time and spatial scales is a step towards understanding the finest and fundamental scales of heating events in the solar corona. The Hi-C instrument has provided the highest spatial and temporal resolution images…

Context: In this paper we present a validation scheme to investigate the quality of coronal magnetic field models, which is based upon comparisons with observational data from multiple sources. Aims: Many of these coronal models may use a…

Solar and Stellar Astrophysics · Physics 2022-02-09 A. Wagner , E. Asvestari , M. Temmer , S. G. Heinemann , J. Pomoell

Spatially averaged (> 50'') EUV spectral lines in the transition region of solar quiet regions are known to be redshifted. Because the mechanism underlying this phenomenon is unclear, we require additional physical information on the lower…

Solar and Stellar Astrophysics · Physics 2016-01-13 N. Kitagawa , H. Hara , T. Yokoyama

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.…

Understanding the density structure of the solar corona is important for modeling both coronal heating and the solar wind. Direct measurements are difficult because of line-of-sight integration and possible unresolved structures. We present…

Solar and Stellar Astrophysics · Physics 2016-09-28 Michael Hahn , Daniel Wolf Savin

Extracting CMB B-mode polarization from complicated foregrounds is a challenging task in searching for inflationary gravitational waves. We propose the ABS method as a blind and analytical solution to this problem. It applies to the…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-09 Pengjie Zhang , Jun Zhang , Le Zhang

High resolution spectra from the Hinode EUV Imaging Spectrometer (EIS) have revealed that coronal spectral line profiles are sometimes asymmetric, with a faint enhancement in the blue wing on the order of 100 km/s. These asymmetries could…

Solar and Stellar Astrophysics · Physics 2015-06-11 David H. Brooks , Harry P. Warren

This thesis strives to improve our understanding of solar activity, specifically the behaviour of solar flares and coronal mass ejections. An investigation into the hydrodynamic evolution of a confined solar flare was carried out using…

Solar and Stellar Astrophysics · Physics 2012-10-19 Claire L. Raftery

Many models for coronal loops have difficulty explaining the observed EUV brightness of the transition region, which is often significantly less than theoretical models predict. This discrepancy has been addressed by a variety of approaches…

Solar and Stellar Astrophysics · Physics 2009-08-24 Bart De Pontieu , Viggo H. Hansteen , Scott W. McIntosh , Spiros Patsourakos

Recently, it has been proposed that the magnetic-field-induced transition (MIT) in Fe X can be used to measure coronal magnetic field strengths. Several techniques, the direct line ratio technique and the weak and strong magnetic field…

Solar and Stellar Astrophysics · Physics 2023-03-08 Yajie Chen , Xianyong Bai , Hui Tian , Wenxian Li , Feng Chen , Zihao Yang , Yang Yang

SDO/EVE provides rich information of the thermodynamic processes of solar activities, particularly of solar flares. Here, we develop a method to construct thermodynamic spectrum (TDS) charts based on the EVE spectral lines. This tool could…

Solar and Stellar Astrophysics · Physics 2016-03-11 Yuming Wang , Zhenjun Zhou , Jie Zhang , Kai Liu , Rui Liu , Chenglong Shen , Phillip C. Chamberlin

We consider two areas of research that have been developing in parallel over the last decade: blind source separation (BSS) and electromagnetic source estimation (ESE). BSS deals with the recovery of source signals when only mixtures of…

Data Analysis, Statistics and Probability · Physics 2015-01-22 Kevin H. Knuth , Herbert G. Vaughan

One of the outstanding problems in all of space science is uncovering how the solar corona is heated to temperatures greater than 1 MK. Though studied for decades, one of the major difficulties in solving this problem has been unraveling…

Solar and Stellar Astrophysics · Physics 2015-06-15 Nicholeen M. Viall , James A. Klimchuk

The Solar Dynamics Observatory (SDO), a NASA multi-spectral decade-long mission that has been daily producing terabytes of observational data from the Sun, has been recently used as a use-case to demonstrate the potential of machine…

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