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Related papers: Density Fluctuations in a Polar Coronal Hole

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The solar corona is much hotter than the photosphere and chromosphere, but the physical mechanism responsible for heating the coronal plasma remains unidentified yet. The thermal microwave emission, which is produced in strong magnetic…

Solar and Stellar Astrophysics · Physics 2025-08-27 Alexey A. Kuznetsov , Gregory D. Fleishman , Gelu M. Nita , Sergey A. Anfinogentov

We study intensity disturbances above a solar polar coronal hole seen in the AIA 171 \AA\ and 193 \AA\ passbands, aiming to provide more insights into their physical nature. The damping and power spectra of the intensity disturbances with…

Solar and Stellar Astrophysics · Physics 2016-06-08 Fangran Jiao , Lidong Xia , Zhenghua Huang , Bo Li , Hui Fu , Ding Yuan , Kalugodu Chandrashekhar

It was recently suggested by Boldyrev & Gwinn that the characteristics of radio scintillations from distant pulsars are best understood if the interstellar electron-density fluctuations that cause the time broadening of the radio pulses…

Astrophysics · Physics 2010-11-11 Stanislav Boldyrev , Arieh Konigl

Coronal Holes (CHs) have subdued intensity and net blueshifts when compared to Quiet Sun (QS) at coronal temperatures. At transition region temperatures, such differences are obtained for regions with identical photospheric absolute…

Solar and Stellar Astrophysics · Physics 2021-11-30 Vishal Upendran , Durgesh Tripathi

We have studied the fluctuations of the soft (0.9-2 keV) X-ray background intensity for ~10 arcmin and ~2 arcmin beam sizes, using 80 high galactic latitude medium-deep images from the ROSAT position sensitive proportional counter (PSPC).…

Astrophysics · Physics 2015-06-24 F. J. Carrera , A. C. Fabian , X. Barcons

We first study the solar flare time sequence based on the GOES16 data. We find that the power spectrum density of the low-energy (E\leq E_{mean}) flare shows 1/f fluctuations, but the high-energy (E>E_{mean}) flare shows a flat spectrum.…

Solar and Stellar Astrophysics · Physics 2023-10-12 Masahiro Morikawa , Akika Nakamichi

We investigate the turbulent properties of 12 interplanetary coronal mass ejections (ICMEs) observed by Solar Orbiter between 0.29 and 1.0 AU. We analyze fluctuation power, spectral indices, break scales, and correlations between magnetic…

Solar and Stellar Astrophysics · Physics 2026-01-13 Jyoti Sheoran , Supratik Banerjee , Vaibhav Pant , Dipankar Banerjee , M. Saleem Khan

We investigate the clustering of galaxies in the QDOT redshift survey of IRAS galaxies. We find that the redshift space two-point correlation function is well approximated by a power-law of slope -1.11+\-0.09, with clustering length…

Astrophysics · Physics 2015-06-24 Ben Moore , Carlos Frenk , George Efstathiou , Will Saunders

Pulsar dispersion measures (DMs) have been used to model the electron density of the interstellar medium (ISM) in the Galactic disk as a plane-parallel medium, despite significant scatter in the DM-distance distribution and strong evidence…

Astrophysics of Galaxies · Physics 2020-07-10 Stella Koch Ocker , James M. Cordes , Shami Chatterjee

We present multi-frequency polarization observations of the diffuse radio synchrotron background modulated by Faraday rotation, in two directions of positive latitude. No extended total intensity I is observed, which implies that total…

Astrophysics · Physics 2014-10-13 M. Haverkorn , P. Katgert , A. G. de Bruyn

Using magnetohydrodynamic simulations of fluctuation dynamos, we perform broad-bandwidth synthetic observations to investigate the properties of polarized synchrotron emission and the role that Faraday rotation plays in inferring the…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-25 Sharanya Sur , Aritra Basu , Kandaswamy Subramanian

The aim of this paper is to demonstrate the effect of turbulent background density fluctuations on flare-accelerated electron transport in the solar corona. Using the quasi-linear approximation, we numerically simulated the propagation of a…

Solar and Stellar Astrophysics · Physics 2015-06-12 I. G. Hannah , E. P. Kontar , H. A. S. Reid

The real-space optical depth distribution along the line of sight to the QSO Q1422+231 is recovered from two HIRES spectra. The first two moments of the truncated optical depth distribution are used to constrain the density fluctuation…

Astrophysics · Physics 2009-10-31 Adi Nusser , Martin Haehnelt

Galaxy clusters form through hierarchical assembly, where smaller substructures merge to build the largest gravitationally bound objects in the universe. These mergers, combined with feedback from AGN, filamentary accretion, and other…

The instrumental advances made in this new era of 4-meter class solar telescopes with unmatched spectropolarimetric accuracy and sensitivity, will enable the study of chromospheric magnetic fields and their dynamics with unprecedented…

Solar and Stellar Astrophysics · Physics 2021-01-20 M. Stangalini , D. Baker , G. Valori , D. B. Jess , S. Jafarzadeh , M. Murabito , A. S. H. To , D. H. Brooks , I. Ermolli , F. Giorgi , C. D. MacBride

Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed…

Solar and Stellar Astrophysics · Physics 2015-05-14 Steven R. Cranmer

The temperatures of the heavy ions ($T_i$) in the solar corona provide critical information about the heating mechanism of the million-degree corona. However, the measurement of $T_i$ is usually challenging due to the nonthermal motion,…

Solar and Stellar Astrophysics · Physics 2023-05-17 Yingjie Zhu , Judit Szente , Enrico Landi

Within the quiet Sun corona imaged at 1 MK, much of the field of view consists of diffuse emission that appears to lack the spatial structuring that is so evident in coronal loops or bright points. We seek to determine if these diffuse…

Recent SECCHI COR2 observations on board STEREO-A spacecraft have detected density structures at a distance of 2.5--15~R propagating with periodicity of about 90~minutes. The observations show that the density structures probably formed in…

Solar and Stellar Astrophysics · Physics 2017-04-26 O. S. Pylaev , T. V. Zaqarashvili , A. I. Brazhenko , V. N. Melnik , A. Hanslmeier , M. Panchenko
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