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Related papers: Density Fluctuations in a Polar Coronal Hole

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Linear RMS-flux relation has been well established in different spectral states of all accreting systems. In this work, we study the evolution of the frequency-dependent RMS-flux relation of MAXI J1820+070 during the initial decaying phase…

High Energy Astrophysical Phenomena · Physics 2024-01-04 Yanan Wang , Shuang-Nan Zhang

We study the height variations of the sizes of chromospheric and transition-region features in a small coronal hole and the adjacent quiet Sun, considering images of the intensity, Doppler shift, and non-thermal motion of ultraviolet…

Solar and Stellar Astrophysics · Physics 2011-08-31 H. Tian , E. Marsch , C. -Y. Tu , L. -D. Xia , J. -S. He

The third year of observations with the Python microwave background experiment densely sample a $5.5^o\times 22^o$ region of sky that includes the fields measured during the first two years of observations with this instrument. The sky is…

Astrophysics · Physics 2009-10-28 S. R. Platt , J. Kovac , M. Dragovan , J. B. Peterson , J. E. Ruhl

Fuzzy dark matter of ultra-light axions has gained attention, largely in light of the galactic scale problems associated with cold dark matter. But the large de Broglie wavelength, believed to possibly alleviate these problems, also leads…

Astrophysics of Galaxies · Physics 2020-01-08 Amr El-Zant , Jonathan Freundlich , Francoise Combes , Anaelle Halle

Comparison of appropriate theoretical derived line ratios with observational data can yield estimates of a plasma's physical parameters, such as electron density or temperature. The usual practice in the calculation of the line ratio is the…

Solar and Stellar Astrophysics · Physics 2014-11-20 J. G. Doyle , S. Chapman , P. Bryans , D. Perez-Suarez , A. Singh , H. Summers , D. W. Savin

We perform a statistical study on the frequency-dependent damping of slow waves propagating along polar plumes and interplumes in the solar corona. Analysis of a large sample of extreme ultraviolet (EUV) imaging data with high spatial and…

Solar and Stellar Astrophysics · Physics 2018-02-14 Sudip Mandal , S. Krishna Prasad , Dipankar Banerjee

We have explored the magnetic flux evolution and temperature variation in a coronal-hole region, using Big Bear Solar Observatory (BBSO) deep magnetograms and {\it SOHO}/EIT images observed from 2005 October 10 to 14. For comparison, we…

Astrophysics · Physics 2010-11-11 Jun Zhang , Guiping Zhou , Jingxiu Wang , Haimin Wang

We present a 2.5-dimensional magnetohydrodynamic simulation of a systematically rotating prominence inside its coronal cavity using the open-source \texttt{MPI-AMRVAC} code. Our simulation starts from a non-adiabatic, gravitationally…

Solar and Stellar Astrophysics · Physics 2023-07-28 Valeriia Liakh , Rony Keppens

Refractive Interstellar Scintillation (RISS) effects on pulsar signals are powerful techniques for discriminating between different models that have been proposed for the power spectrum of plasma density fluctuations in the Interstellar…

Astrophysics · Physics 2007-05-23 N. D. Ramesh Bhat , Yashwant Gupta , A. Pramesh Rao

Plasma loops or plumes rooted in sunspot umbrae often harbor downflows with speeds of 100 km/s. These downflows are supersonic at transition region temperatures of 0.1 MK. The source of these flows is not well understood. We aim to…

Solar and Stellar Astrophysics · Physics 2022-03-16 Hechao Chen , Hui Tian , Leping Li , Hardi Peter , Lakshmi Pradeep Chitta , Zhenyong Hou

Coronal heating through the explosive release of magnetic energy remains an open problem in solar physics. Recent hydrodynamical models attempt an investigation by placing swarms of 'nanoflares' at random sites and times in modeled…

Solar and Stellar Astrophysics · Physics 2016-11-30 K. Moraitis , A. Toutountzi , H. Isliker , M. Georgoulis , L. Vlahos , G. Chintzoglou

Compressive fluctuations are a minor yet significant component of astrophysical plasma turbulence. In the solar wind, long-wavelength compressive slow-mode fluctuations lead to changes in $\beta_{\parallel \mathrm p}\equiv 8\pi n_{\mathrm…

Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in EUV images over a decade, and are widely accepted to be slow magnetosonic waves. However, spectroscopic observations from Hinode/EIS revealed…

Solar and Stellar Astrophysics · Physics 2015-11-04 X. Fang , D. Yuan , T. Van Doorsselaere , R. Keppens , C. Xia

We combine observations of the Coronal Multi-channel Polarimeter (CoMP) and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) to study the characteristic properties of (propagating) Alfvenic motions and…

Solar and Stellar Astrophysics · Physics 2015-07-02 Jiajia Liu , Scott W. McIntosh , Ineke De Moortel , Yuming Wang

Heavy ions are markers of the physical processes responsible for the density and temperature distribution throughout the fine scale magnetic structures that define the shape of the solar corona. One of their properties, whose empirical…

Solar and Stellar Astrophysics · Physics 2018-06-27 Benjamin Boe , Shadia Habbal , Miloslav Druckmuller , Enrico Landi , Ehsan Kourkchi , Adalbert Ding , Pavel Starha , Joseph Hutton

It is now well established that the Alfv\'enic waves are ubiquitous in the solar corona. However, the Alfv\'enic wave energy estimated from the Doppler velocity measurements in the corona was found to be four orders of magnitude less than…

Solar and Stellar Astrophysics · Physics 2019-09-04 Vaibhav Pant , Norbert Magyar , Tom Van Doorsselaere , Richard J. Morton

Using long-duration observations in the He II 304 Angstrom passband of the Solar and Heliospheric Observatory (SOHO) Extreme-ultraviolet Imaging Telescope (EIT) we investigate the spatial and temporal appearance of impulsive intensity…

Astrophysics · Physics 2009-01-19 Scott W. McIntosh

The footprint of LoTSS-DR2 covers 309 PSZ2 galaxy clusters, 83 of which host a radio halo and 26 host a radio relic(s). It provides us an excellent opportunity to statistically study the properties of extended cluster radio sources,…

Recent observations have demonstrated that waves which are capable of carrying large amounts of energy are ubiquitous throughout the solar corona. However, the question of how this wave energy is dissipated (on which time and length scales)…

Solar and Stellar Astrophysics · Physics 2014-11-20 Jiajia Liu , Scott W. McIntosh , Ineke De Moortel , James Threlfall , Christian Bethge

Measurements of the temperature and density structure of the solar corona provide critical constraints on theories of coronal heating. Unfortunately, the complexity of the solar atmosphere, observational uncertainties, and the limitations…

Solar and Stellar Astrophysics · Physics 2009-07-22 Harry P. Warren , David H. Brooks
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