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One of the most interesting discoveries of the X-ray Telescope and EUV Imaging Spectrometer (EIS) on board the Hinode solar observatory is the presence of persistent high temperature high speed outflows from the edges of active regions.…

Solar and Stellar Astrophysics · Physics 2015-05-20 David H. Brooks , Harry P. Warren

The EUV Imaging Spectrometer (EIS) instrument on board the Hinode satellite has access to some of the best coronal density diagnostics and the high sensitivity of the instrument now allows electron number density, N_e, measurements to an…

Astrophysics · Physics 2009-11-13 P. R. Young , T. Watanabe , H. Hara , J. T. Mariska

The characteristic electron densities, temperatures, and thermal distributions of 1MK active region loops are now fairly well established, but their coronal magnetic field strengths remain undetermined. Here we present measurements from a…

Solar and Stellar Astrophysics · Physics 2021-07-14 David H. Brooks , Harry P. Warren , Enrico Landi

The \textit{High resolution Coronal Imager (Hi-C)} has provided the sharpest view of the EUV corona to date. In this paper we exploit its impressive resolving power to provide the first analysis of the fine-scale structure of moss in an…

Solar and Stellar Astrophysics · Physics 2015-06-19 R. J. Morton , J. A. McLaughlin

The term `solar tornadoes' has been used to describe apparently rotating magnetic structures above the solar limb, as seen in high resolution images and movies from the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics…

Solar and Stellar Astrophysics · Physics 2015-09-30 Peter Levens , Nicolas Labrosse , Lyndsay Fletcher , Brigitte Schmieder

We present observations of transient active region heating events observed with the Extreme Ultraviolet Imaging Spectrometer (EIS) and X-ray Telescope (XRT) on Hinode. This initial investigation focuses on NOAA active region 10940 as…

In order to better understand the possibility of coronal heating by MHD waves, we analyze Fe xii 195.12{\AA} data observed with EUV Imaging Spectrometer (EIS) onboard Hinode. We performed a Fourier analysis of EUV intensity and Doppler…

Solar and Stellar Astrophysics · Physics 2015-05-19 Naomasa Kitagawa , Takaaki Yokoyama , Shinsuke Imada , Hirohisa Hara

Using a full spectral scan of an active region from the Extreme-Ultraviolet Imaging Spectrometer (EIS) we have obtained Emission Measure EM$(T)$ distributions in two different moss regions within the same active region. We have compared…

Solar and Stellar Astrophysics · Physics 2015-05-19 Durgesh Tripathi , Helen E. Mason , James A. Klimchuk

The relationships among coronal loop structures at different temperatures is not settled. Previous studies have suggested that coronal loops in the core of an active region are not seen cooling through lower temperatures and therefore are…

Solar and Stellar Astrophysics · Physics 2011-02-11 Ignacio Ugarte-Urra , Harry P. Warren , David H. Brooks

Coronal active regions are studied using Hinode/EIS observations in the EUV line Fe XII {\lambda}195.12 by analyzing their line profiles from 2006 December to 2019 December. The period covers the last 2 yr of solar cycle 23 and solar cycle…

Solar and Stellar Astrophysics · Physics 2022-05-24 Maya Prabhakar , K. P Raju

We analyze a solar active region observed by the Hinode CaII H line using the time-distance helioseismology technique, and infer wave-speed perturbation structures and flow fields beneath the active region with a high spatial resolution.…

Solar and Stellar Astrophysics · Physics 2014-11-20 Junwei Zhao , Alexander G. Kosovichev , Takashi Sekii

Previous observations have not been able to exclude the possibility that high temperature active region loops are actually composed of many small scale threads that are in various stages of heating and cooling and only appear to be in…

Solar and Stellar Astrophysics · Physics 2014-11-20 Harry P. Warren , Amy R. Winebarger , David H. Brooks

Understanding the relationship between the magnetic field and coronal heating is one of the central problems of solar physics. However, studies of the magnetic properties of impulsively heated loops have been rare. We present results from a…

Solar and Stellar Astrophysics · Physics 2019-06-12 Ignacio Ugarte-Urra , Nicholas A. Crump , Harry P. Warren , Thomas Wiegelmann

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

The Soft X-ray intensity of loops in active region cores and corresponding footpoint, or moss, intensity observed in the EUV remain steady for several hours of observation. The steadiness of the emission has prompted many to suggest that…

Astrophysics · Physics 2009-11-13 A. R Winebarger , H. P. Warren , D. A. Falconer

A comprehensive study of the physical parameters of active region fan loops is presented using the observations recorded with the Interface Region Imaging Spectrometer (IRIS), the EUV Imaging Spectrometer (EIS) on-board Hinode and the…

Solar and Stellar Astrophysics · Physics 2017-02-08 Avyarthana Ghosh , Durgesh Tripathi , G. R. Gupta , Vanessa Polito , Helen E. Mason , Sami K. Solanki

A key goal of the Solar Orbiter mission is to connect elemental abundance measurements of the solar wind enveloping the spacecraft with EUV spectroscopic observations of their solar sources, but this is not an easy exercise. Observations…

The Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft obtains high resolution spectra of the solar atmosphere in two wavelength ranges: 170 - 210 and 250 - 290 angstroms. These wavelength regions contain a wealth of…

Solar and Stellar Astrophysics · Physics 2014-11-18 Yuan-Kuen Ko , George A. Doschek , Harry P. Warren , Peter R. Young

Variations in the propagation of globally-propagating disturbances (commonly called "EIT waves") through the low solar corona offer a unique opportunity to probe the plasma parameters of the solar atmosphere. Here, high-cadence observations…

Solar and Stellar Astrophysics · Physics 2015-06-16 David M. Long , David R. Williams , Stéphane Régnier , Louise K. Harra

Many studies of the solar corona have shown that the observed X-ray luminosity is well correlated with the total unsigned magnetic flux. In this paper we present results from the extensive numerical modeling of active regions observed with…

Astrophysics · Physics 2016-08-30 Harry P. Warren , Amy R. Winebarger