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Related papers: A Genetic Algorithm to model Solar Radio Active Re…

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In this article, we present the application of the weighted horizontal gradient of magnetic field (WGM) flare prediction method to 3-dimensional (3D) extrapolated magnetic configurations of 13 flaring solar active regions (ARs). The main…

Solar and Stellar Astrophysics · Physics 2020-06-24 M. B. Korsos , M. K. Georgoulis , N. Gyenge , S. K. Bisoi , S. Yu , S. Poedts , C. J. Nelson , J. Liu , Y. Yan , R. Erdelyi

The radio emission of the quiet Sun in the metric and decametric bands has not been well studied historically due to limitations of existing instruments. It is nominally dominated by thermal brehmsstrahlung of the solar corona, but may also…

Solar and Stellar Astrophysics · Physics 2025-05-05 Kamen Kozarev , Mohamed Nedal

Solar active regions contain a broad range of temperatures, with the thermal plasma distribution often observed to peak in the few millions of kelvin. Differential emission measure (DEM) analysis can allow instruments with diverse…

At subterahertz frequencies -- i.e., millimeter and submillimeter wavelengths -- there is a gap of measurements of the solar radius as well as other parameters of the solar atmosphere. As the observational wavelength changes, the radius…

Solar and Stellar Astrophysics · Physics 2021-04-07 Fabian Menezes , Caius L. Selhorst , Carlos Guillermo Giménez de Castro , Adriana Valio

Three-minute oscillations over sunspot's umbra in AR 11131 were observed simultaneously in UV/EUV emission by SDO/AIA and in radio emission by Nobeyama Radioheliograph (NoRH). We use 24-hours series of SDO and 8-hours series of NoRH…

Solar and Stellar Astrophysics · Physics 2015-05-30 V. E. Reznikova , K. Shibasaki , R. A. Sych , V. M. Nakariakov

The heating of the solar wind is a key to understand its dynamics and acceleration process. The observed radial decrease of proton temperature in the solar wind is slow compared to the adiabatic prediction and it is thought to be caused by…

Space Physics · Physics 2026-03-03 Victor Montagud-Camps , Roland Grappin , Andrea Verdini

(Abridged) We constrain simulated all-sky maps in total intensity, linear polarization, and rotation measure (RM) by observations. We test a number of large-scale magnetic field configurations and take the properties of the warm…

Astrophysics · Physics 2009-11-13 X. H. Sun , W. Reich , A. Waelkens , T. Enßlin

The solar transition region (TR), in which above the photosphere the tempera- ture increases rapidly and the density drops dramatically, is believed to play an important role in coronal heating and solar wind acceleration. Long-lasting…

Solar and Stellar Astrophysics · Physics 2017-08-02 H. Tian , W. Curdt , J. -S. He

We present a seismological method to probe the solar atmosphere above sunspot umbrae with three-minute oscillations. Our technique allows us to estimate both the vertical distance between atmospheric layers and the wave-propagation speed…

Solar and Stellar Astrophysics · Physics 2017-12-27 A. S. Deres , S. A. Anfinogentov

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

Due to their characteristic temperature and density, loop structures in active regions (ARs) can be seen bright in extreme ultraviolet (EUV) and soft X-ray images. The semiempirical determination of the three-dimensional (3D) distribution…

Solar and Stellar Astrophysics · Physics 2020-12-16 F. A. Nuevo , C. Mac Cormack , M. López Fuentes , A. M. Vásquez , C. H. Mandrini

A detailed study is presented of the decaying solar active region NOAA 10103 observed with the Coronal Diagnostic Spectrometer (CDS), the Michelson Doppler Imager (MDI) and the Extreme-ultraviolet Imaging Telescope (EIT) onboard the Solar…

Astrophysics · Physics 2007-05-23 R. O. Milligan , P. T. Gallagher , M. Mathioudakis , F. P. Keenan , D. S. Bloomfield

Seeking to establish whether active region upflow material contributes to the slow solar wind, we examine in detail the plasma upflows from Active Region (AR)10978, which crossed the Sun's disc in the interval 8 to 16 December, 2007 during…

Solar and Stellar Astrophysics · Physics 2015-06-19 J. L. Culhane , D. H. Brooks , L. van Driel-Gesztelyi , P. Demoulin , D. Baker , M. L. DeRosa , C. H. Mandrini , L. Zhao , T. H. Zurbuchen

A new dataset of atomic oxygen and molecular nitrogen number density profiles, along with thermospheric temperature profiles between 180 and 500 km, has been developed. These profiles are derived from solar occultation measurements made by…

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

Constraining the frequency of energy deposition in magnetically-closed active region cores requires sophisticated hydrodynamic simulations of the coronal plasma and detailed forward modeling of the optically-thin line-of-sight integrated…

Solar and Stellar Astrophysics · Physics 2021-10-13 W. T. Barnes , S. J. Bradshaw , N. M. Viall

The lower solar atmosphere is an intrinsically multi-component and collisional environment with electron and proton collision frequencies in the range $10^{8}-10^{10}$ Hz, which may be considerably higher than the gyro-frequencies for both…

Solar and Stellar Astrophysics · Physics 2013-06-04 J. Vranjes , P. S. Krstic

Observations of He-like and H-like Ar (Ar XVII and Ar XVIII) lines at 3.949 Angstroms and 3.733 Angstroms respectively with the RESIK X-ray spectrometer on the CORONAS-F spacecraft, together with temperatures and emission measures from the…

Solar and Stellar Astrophysics · Physics 2015-05-19 J. Sylwester , B. Sylwester , K. J. H. Phillips , V. D. Kuznetsov

The absolute brightness temperature of the Sun at millimeter wavelengths is an important diagnostic of the solar chromosphere. Because the Sun is so bright, measurement of this property usually involves the operation of telescopes under…

Solar and Stellar Astrophysics · Physics 2017-01-02 Kazumasa Iwai , Masumi Shimojo , Shinichiro Asayama , Tetsuhiro Minamidani , Stephen White , Timothy Bastian , Masao Saito

Recent three-dimensional radiation hydrodynamic simulations by Wedemeyer et al. (2004) suggest that the solar chromosphere is highly structured in space and time on scales of only 1000 km and 20-25 sec, resp.. The resulting pattern consists…

Astrophysics · Physics 2007-05-23 S. Wedemeyer-Boehm , H. -G. Ludwig , M. Steffen , B. Freytag , H. Holweger