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Solar extreme-ultraviolet (EUV) lines emitted by highly charged ions have been extensively studied to discuss the issue of coronal heating and solar wind acceleration. Based on observations of the polar corona by the SUMER/SOHO…

Solar and Stellar Astrophysics · Physics 2015-06-22 G. Q. Zhao , D. J. Wu , C. B. Wang

We use 3D radiation magnetohydrodynamic models to investigate how the thermodynamic quantities in the simulation are encoded in observable quantities, thus exploring the diagnostic potential of the 133.5 nm lines. We find that the line core…

Solar and Stellar Astrophysics · Physics 2015-09-30 Bhavna Rathore , Mats Carlsson , Jorrit Leenaarts , Bart De Pontieu

From 1979--1996 the Green Bank Interferometer was used by the Naval Research Laboratory to monitor the flux density from 146 compact radio sources at frequencies near 2 and 8 GHz. We filter the ``light curves'' to separate intrinsic…

Astrophysics · Physics 2009-11-11 B. Rickett , T. J. W. Lazio , F. D. Ghigo

We investigate the plasma dynamics (outflow speed and turbulence) inside polar plumes. We compare line profiles (mainly of \ion{O}{6}) observed by the UVCS instrument on SOHO at the minimum of solar cycle 22-23 with model calculations. We…

Astrophysics · Physics 2010-11-11 N. -E. Raouafi , J. W. Harvey , S. K. Solanki

The excess broadening of high-temperature spectral lines, long observed near the tops of flare arcades, is widely considered to result from magnetohydrodynamic (MHD) turbulence. According to different theories, plasma turbulence is also…

Solar and Stellar Astrophysics · Physics 2024-07-18 William Ashfield , Vanessa Polito , Sijie Yu , Hannah Collier , Laura Hayes

Collisional absorption of laser light in a homogeneous, under-dense plasma is studied by a new particle-in-cell (PIC) simulation code considering one-dimensional slab-plasma geometry. Coulomb collisions between charge particles in plasma…

Plasma Physics · Physics 2017-03-06 M. Kundu

We report on a systematic center-to-limb variation in measured helioseismic travel times, which must be taken into account for an accurate determination of solar interior meridional flows. The systematic variation, found in time-distance…

Solar and Stellar Astrophysics · Physics 2015-06-04 Junwei Zhao , Kaori Nagashima , R. S. Bogart , A. G. Kosovichev , T. L. Duvall

The Very Local Interstellar Medium (VLISM) contains clouds which consist of partially-ionized plasma. These clouds can be effectively diagnosed via high resolution optical and ultraviolet spectroscopy of the absorption lines they form in…

Astrophysics of Galaxies · Physics 2015-05-19 Steven R. Spangler , Allison H. Savage , Seth Redfield

The solar surface magnetic field is connected with and even controls most of the solar activity phenomena. Zeeman effect diagnostics allow for measuring only a small fraction of the fractal-like structured magnetic field. The remaining…

Solar and Stellar Astrophysics · Physics 2015-05-27 A. I. Shapiro , D. M. Fluri , S. V. Berdyugina , M. Bianda , R. Ramelli

Surges have regularly been observed mostly in H$_{\alpha}$ 6563~{\AA} and Ca~{\sc ii} 8542~{\AA}. However, surge$'$s response to other prominent lines of the interface-region (Mg~{\sc ii} k 2796.35~{\AA} $\&$ h 2803.52~{\AA}, O~{\sc iv}…

Solar and Stellar Astrophysics · Physics 2021-07-07 Pradeep Kayshap , Rajdeep Singh Payal , Sharad C. Tripathi , Harihara Padhy

Dynamics of hot chromospheric plasma of solar flares is a key to understanding of mechanisms of flare energy release and particle acceleration. A moderate M1.0 class flare of 12 June, 2014 (SOL2014-06-12T21:12) was simultaneously observed…

Eclipses are very favourable for the photosphere- chromosphere and corona interface observation as the occultation takes place in space, free of parasitic light coming from the occulting disk (the Moon). Independently, EUV filtergrams of…

Solar and Stellar Astrophysics · Physics 2013-12-18 Cyrille Bazin

This study analyzed the Doppler shift in the solar spectrum using the Interface Region Imaging Spectrograph (IRIS). Two types of oscillations were investigated: long period damp and short period damp. The researchers observed periodic…

Solar and Stellar Astrophysics · Physics 2024-12-25 E. Tavabi , R. Sadeghi

We investigate the statistics of the intensity distributions as function of the wavelength for Ca II H and the CA II IR line at 854.2 nm to estimate the energy content. We derived the intensity variations at different heights of the solar…

Solar and Stellar Astrophysics · Physics 2013-03-14 C. Beck , R. Rezaei , K. G. Puschmann

We use the three-dimensional hydrodynamic code of Stein and Nordlund to realistically simulate the upper layers of the solar convection zone in order to study physical characteristics of solar oscillations. Our first result is that the…

Astrophysics · Physics 2009-10-31 D. Georgobiani , A. G. Kosovichev , R. Nigam , A. Nordlund , R. F. Stein

Context. In the upper atmosphere of the Sun observations show convincing evidence for crossing and twisted structures, which are interpreted as mutual helicity and self-helicity. Aims. We use observations with the new Interface Region…

Solar and Stellar Astrophysics · Physics 2014-10-29 Leping Li , Hardi Peter , Feng Chen , Jun Zhang

Context. Understanding the close relationship between the plasma and the magnetic field is important to describe and explain the observed complex dynamics of solar prominences. Aims. We determine if a close relationship between plasma and…

Solar and Stellar Astrophysics · Physics 2017-11-01 P. J. Levens , N. Labrosse , B. Schmieder , A. López Ariste , L. Fletcher

Solar surface magneto-convection appears as granulation pattern that impacts spectral lines in terms of both shape and wavelength. Such induced effects also tend to vary over the observed solar disc because of the changing observation angle…

Solar and Stellar Astrophysics · Physics 2023-05-03 M. Ellwarth , S. Schäfer , A. Reiners , M. Zechmeister

Aims: We investigate a new method to for obtaining the plasma parameters of solar prominences observed in the Mgii h&k spectral lines by comparing line profiles from the IRIS satellite to a bank of profiles computed with a one-dimensional…

Solar and Stellar Astrophysics · Physics 2021-09-01 Aaron W. Peat , Nicolas Labrosse , Brigitte Schmieder , Krzysztof Barczynski

Semi-empirical models of the solar Chromosphere show in their emission spectrum, tomography property at millimeter, sub-millimeter, and infrared wavelengths for the center of the solar disk. In this work, we studied this property in the…

Solar and Stellar Astrophysics · Physics 2017-03-22 Victor De la Luz , J. A. Gonzalez-Esparza , P. Corona-Romero , J. Mejia-Ambriz
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