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Related papers: The Solar Radius in the EUV during the Cycle XXIII

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The plasma parameters such as the electron density and temperature plays a key role in the dynamics of the solar atmosphere. These characteristics are important in solar physics, because they can help to understand the physics in the solar…

Solar and Stellar Astrophysics · Physics 2018-04-12 J. M Rodríguez Gómez , L. Vieira , A. Dal Lago , J. Palacios

We use The Sun Watcher with Active Pixel System detector and Image Processing (SWAP) imager onboard the Project for Onboard Autonomy 2 (PROBA2) mission to study the evolution of large-scale EUV structures in the solar corona observed…

The correlation between solar Extreme Ultra-Violet (EUV) radiation above 8.8 eV and the release of sodium from the lunar surface via photon-stimulated desorption (PSD) is investigated. We use simultaneous measurements of EUV photon flux and…

Earth and Planetary Astrophysics · Physics 2025-09-09 A Devaraj , S Narendranath , Sreeja S Kartha , M Sarantos , Akhil Krishna R , Blesson Mathew , T Sivarani , S Nidhi , P Anbazhagan , G Selvakumar

Solar activity during 2007--2009 was very low, causing anomalously low thermospheric density. A comparison of solar extreme ultraviolet (EUV) irradiance in the He II spectral band (26 to 34 nm) from the Solar Extreme ultraviolet Monitor…

Solar and Stellar Astrophysics · Physics 2015-06-15 Leonid Didkovsky , Joseph B. Gurman

Verified and updated calibrated absolute solar flux in the He II 30.4 nm spectral band-pass as measured by the Solar EUV Monitor (SEM) allows us to study variations of the solar EUV irradiance near the minima of Solar Cycles 22/23 and…

Solar and Stellar Astrophysics · Physics 2009-11-05 Leonid Didkovsky , Darrell Judge , Seth Wieman , Don McMullin

The Solar Diameter Monitor measured the duration of solar meridian transits during the 6 years 1981 to 1987, spanning the declining half of solar cycle 21. We have combined these photoelectric measurements with models of the solar…

Astrophysics · Physics 2008-11-26 T. M. Brown , J. Christensen-Dalsgaard

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

The extreme-ultraviolet (EUV; 100 -- 911 \AA) spectra of F, G, K, and M stars provide diagnostics of the stellar chromosphere through the corona, with line and continuum formation temperatures spanning roughly 10$^{4}$ - 10$^{7}$ K. The EUV…

The solar transition region (TR) is a narrow interface between the chromosphere and corona, where emitted radiation contains critical information pertinent to coronal heating processes. We conducted 2-dimensional radiation…

Solar and Stellar Astrophysics · Physics 2025-01-22 Takuma Matsumoto

Understanding the solar corona requires knowledge of its dynamics through its various layers and subsequent connectivity to the heliosphere. This requires understanding the nature of the outflows and the physical transitions through the…

Solar and Stellar Astrophysics · Physics 2023-03-29 Nathalia Alzate , Huw Morgan , Simone Di Matteo

A new method for automated detection of polar coronal holes is presented. This method, called perimeter tracing, uses a series of 171, 195, and 304 \AA\ full disk images from the Extreme ultraviolet Imaging Telescope (EIT) on SOHO over…

Solar and Stellar Astrophysics · Physics 2015-05-13 Michael S. Kirk , W. Dean Pesnell , C. Alex Young , Shea A. Hess Webber

The Sun Watcher with Active Pixels and Image Processing (SWAP) EUV solar telescope on board the Project for On-Board Autonomy 2 (PROBA2) spacecraft has been regularly observing the solar corona in a bandpass near 17.4 nm since February…

Solar and Stellar Astrophysics · Physics 2015-06-17 Daniel B. Seaton , Anik De Groof , Paul Shearer , David Berghmans , Bogdan Nicula

The Sun is an extraordinary workbench, from which several fundamental astronomical parameters can be measured with high precision. Among these parameters, the solar radius $R_{\odot}$ plays an important role in several aspects, such as in…

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

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

The Sun emits radiation at several wavelengths of the electromagnetic spectrum. In the optical band, the solar radius is 695,700 km and this is what defines the photosphere, the visible surface of the Sun. However, as the altitude…

Solar and Stellar Astrophysics · Physics 2017-12-20 Fabian Menezes , Adriana Valio

In addition to X-rays, extreme ultraviolet (EUV) rays radiated from solar flares can cause serious problems, such as communication failures and satellite drag. Therefore, methods for forecasting EUV dynamic spectra during flares are…

Solar and Stellar Astrophysics · Physics 2020-05-14 Toshiki Kawai , Shinsuke Imada , Shohei Nishimoto , Kyoko Watanabe , Tomoko Kawate

Recent progress in obtaining high spatial resolution images of the solar corona in the extreme-ultraviolet (EUV) with Hinode, TRACE, SDO and recent Hi-C missions and soft X-ray (SXR) bands opened a new avenue in understanding the solar…

Solar and Stellar Astrophysics · Physics 2014-09-16 V. S. Airapetian , J. Allred

Coronal loops are plasma structures in the solar atmosphere with temperatures reaching millions of Kelvin, shaped and sustained by the magnetic field. However, their morphology and fundamental nature remain subjects of debate. By studying…

Solar and Stellar Astrophysics · Physics 2026-01-14 N. Vasantharaju , H. Peter , L. P. Chitta , S. Mandal

Extracting the temperature of coronal loops is effective in the analysis of solar active region's loops and helps in better understanding of coronal events. To this end, various methods have already been developed like the method developed…

Solar and Stellar Astrophysics · Physics 2019-08-30 Narges Fathalian