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We present an update to the in-flight radiometric calibration of the Hinode EUV Imaging Spectrometer (EIS), revising and extending our previous studies. We analyze full-spectral EIS observations of quiet Sun and active regions from 2007…

Solar and Stellar Astrophysics · Physics 2024-12-02 G. Del Zanna , M. Weberg , H. P. Warren

Quiet Sun and active region spectra from the Hinode/EIS instrument are presented, and the strongest lines from different temperature regions discussed. A list of emission lines recommended to be included in EIS observation studies is…

One of the most important features in the solar atmosphere is magnetic network and its rela- tionship with the transition region (TR), and coronal brightness. It is important to understand how energy is transported into the corona and how…

Solar and Stellar Astrophysics · Physics 2018-03-21 Ehsan Tavabi

The magnetic field plays a pivotal role in many fields of Astrophysics. This is especially true for the physics of the solar atmosphere. Measuring the magnetic field in the upper solar atmosphere is crucial to understand the nature of the…

In previous studies a very hot plasma component has been diagnosed in solar active regions through the images in three different narrow-band channels of SDO/AIA. This diagnostic from EUV imaging data has also been supported by the matching…

Solar and Stellar Astrophysics · Physics 2015-06-18 A. Petralia , F. Reale , P. Testa , G. Del Zanna

Transition region lines in active regions can become strongly enhanced in coronal footpoints and active region blinkers. The weak transition region lines found in the Solar-B/EIS wavebands will thus become useful for diagnostic studies of…

Astrophysics · Physics 2007-08-14 P. R. Young

Magnetic field extrapolation is an important tool to study the three-dimensional (3D) solar coronal magnetic field which is difficult to directly measure. Various analytic models and numerical codes exist but their results often drastically…

Solar and Stellar Astrophysics · Physics 2017-06-28 Aiying Duan , Chaowei Jiang , Qiang Hu , Huai Zhang , G. Allen Gary , S. T. Wu , Jinbin Cao

Magnetism defines the complex and dynamic solar corona. Coronal mass ejections (CMEs) are thought to be caused by stresses, twists, and tangles in coronal magnetic fields that build up energy and ultimately erupt, hurling plasma into…

At the Sun, the strongest magnetic fields are routinely detected at dark sunspots. The magnitude of the field is typically about 3000 G, with only a few exceptions that reported the magnetic field in excess of 5000 G. Given that the…

Solar and Stellar Astrophysics · Physics 2019-08-07 Sergey A. Anfinogentov , Alexey G. Stupishin , Ivan I. Mysh'yakov , Gregory D. Fleishman

We determine magnetic fields from the photosphere to the upper chromosphere combining data from the Hinode satellite and the CLASP2.1 sounding rocket experiment. CLASP2.1 provided polarization profiles of the Mg~{|sc ii} $h$ and $k$ lines,…

We review methods to measure magnetic fields within the corona using the polarized light in magnetic-dipole (M1) lines. We are particularly interested in both the global magnetic-field evolution over a solar cycle, and the local storage of…

Solar and Stellar Astrophysics · Physics 2015-06-15 Philip G. Judge , Shadia Habbal , Enrico Landi

Aims. The magnetic field of coronal mass ejections (CMEs) determines their structure, evolution, and energetics, as well as their geoeffectiveness. However, we currently lack routine diagnostics of the near-Sun CME magnetic field, which is…

Solar and Stellar Astrophysics · Physics 2016-09-02 S. Patsourakos , M. K. Georgoulis

Coronal holes are the observational manifestation of the solar magnetic field open to the heliosphere and are of pivotal importance for our understanding of the origin and acceleration of the solar wind. Observations from space missions…

The magnetic fields in the solar atmosphere structure the plasma, store free magnetic energy and produce a wide variety of active solar phenomena, like flare and coronal mass ejections(CMEs). The distribution and strength of magnetic fields…

Solar and Stellar Astrophysics · Physics 2015-06-12 Tilaye Tadesse , T. Wiegelmann , K. Olson , P. J. MacNeice

An application of active contours without edges is presented as an efficient and effective means of extracting and characterizing coronal holes. Coronal holes are regions of low-density plasma on the Sun with open magnetic field lines. As…

Solar and Stellar Astrophysics · Physics 2016-10-05 L. E. Boucheron , M. Valluri , R. T. J. McAteer

Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal phenomena at all scales. We employed STEREO/COR1 data obtained during a deep minimum of solar activity in February 2008…

Solar and Stellar Astrophysics · Physics 2014-05-06 M. Kramar , V. Airapetian , Z. Mikić , J. Davila

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

Plasma composition in the solar atmosphere differs between the photosphere and corona, producing an observable difference in elemental abundance known as the FIP effect. The FIP effect is characterised by the ratio of low to high FIP…

Solar and Stellar Astrophysics · Physics 2026-03-06 Kristena D. Spruksta , David M. Long , Andy S. H. To

Seismic maps of the Sun's far hemisphere, computed from Doppler data from the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) are now being used routinely to detect strong magnetic regions on the far…

Solar and Stellar Astrophysics · Physics 2017-10-11 P. C. Liewer , J. Qiu , C. Lindsey

Sunspots on the surface of the Sun are the observational signatures of intense manifestations of tightly packed magnetic field lines, with near-vertical field strengths exceeding 6,000 G in extreme cases. It is well accepted that both the…