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It is customary to employ a semi-spherical scale model to describe the apparent path of the Sun across the sky, whether it be its diurnal motion or its variation throughout the year. A flat surface and three bent semi-rigid wires…

Popular Physics · Physics 2018-09-25 Alejandro Gangui , Roberto Casazza , Carlos Paez

Using high-resolution numerical simulations we investigate the plasma heating driven by periodic two-fluid acoustic waves that originate at the bottom of the photosphere and propagate into the gravitationally stratified and partially…

Solar and Stellar Astrophysics · Physics 2019-06-26 B. Kuźma , D. Wójcik , K. Murawski

We report the properties of electron distributions and turbulence during a Coronal Mass Ejection (CME) in April 2023 observed by Magnetospheric Multiscale (MMS). The CME exhibits a clear sheath and magnetic cloud (MC), and within the MC,…

Our knowledge of the low solar atmosphere, i.e., the photosphere and chromosphere, is based on the knowledge gained from the observations and the theoretical and numerical modeling of these layers. In this sense, the thermodynamical and…

Solar and Stellar Astrophysics · Physics 2024-03-12 Alberto Sainz Dalda , Aaryan Agrawal , Bart De Pontieu , M. Gosic

Two sequences of solar images obtained by the Transition Region and Coronal Explorer in three UV passbands are studied using wavelet and Fourier analysis and compared to the photospheric magnetic flux measured by the Michelson Doppler…

Solar flares observed in the 200-400 GHz radio domain may exhibit a slowly varying and time-extended component which follows a short (few minutes) impulsive phase and which lasts for a few tens of minutes to more than one hour. The few…

Solar and Stellar Astrophysics · Physics 2011-11-21 G. Trottet , J. -P. Raulin , G. Giménez de Castro , T. Lüthi , A. Caspi , C. H. Mandrini , M. L. Luoni , P. Kaufmann

Solar chromospheric observations of sunspot umbrae offer an exceptional view of magneto-hydrodynamic wave phenomena. In recent years, a wealth of wave signatures related to propagating magneto-acoustic modes have been presented, which…

New analysis confirms our earlier claim [1], [7] of circles of notably low temperature variance, often in concentric sets, in the cosmic microwave background (CMB), discernable in WMAP data. Their reality can be interpreted as evidence of…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-04 V. G. Gurzadyan , R. Penrose

Waves are an integral part of the solar atmosphere, and their characteristics (e.g., dominant period, range of periods, power, and phase angle) change on a diverse spatio-temporal scale. It is well well-established observationally that the…

Solar and Stellar Astrophysics · Physics 2025-06-10 Pradeep Kayshap , K. Murawski , Z. E. Musielak , Suresh Babu

The lack of long and reliable time series of solar spectral irradiance (SSI) measurements makes an accurate quantification of solar contributions to recent climate change difficult. Whereas earlier SSI observations and models provided a…

In this work we investigate the dynamic behavior of inter-network regions of the solar chromosphere. We observed the chromosphere of the quiet Sun using a narrow-band Lyot filter centered at the Ca II K 2v emission peak with a bandpass of…

Astrophysics · Physics 2009-11-11 F. Wöger , S. Wedemeyer-Böhm , W. Schmidt , O. von der Lühe

Cosmic Microwave Background (CMB) full-sky temperature data show a hemispherical asymmetry in power nearly aligned with the Ecliptic. In real space, this anomaly can be quantified by the temperature variance in the northern and southern…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-28 Marcio O'Dwyer , Craig J. Copi , Lloyd Knox , Glenn D. Starkman

A prominent manifestation of the solar dynamo is the 11-year activity cycle, evident in indicators of solar activity, including solar irradiance. Although a relationship between solar activity and the brightness of the Sun had long been…

Solar and Stellar Astrophysics · Physics 2015-07-07 K. L. Yeo

Analyses of the cosmic microwave background (CMB) radiation maps made by the Wilkinson Microwave Anisotropy Probe (WMAP) have revealed anomalies not predicted by the standard inflationary cosmology. In particular, the power of the…

Earth and Planetary Astrophysics · Physics 2014-11-20 V. Dikarev , O. Preuss , S. Solanki , H. Krueger , A. Krivov

The Sun is replete with magnetic fields, with sunspots, pores and plage regions being their most prominent representatives on the solar surface. But even far away from these active regions, magnetic fields are ubiquitous. To a large extent,…

Solar and Stellar Astrophysics · Physics 2015-11-05 Andreas Lagg , Bruce Lites , Jack Harvey , Sanjay Gosain , Rebecca Centeno

The solar atmosphere is permeated by various types of waves that originate from subsurface convection. As these waves propagate upward, they encounter they encounter a steep decrease in the density of the medium, leading to their steepening…

Solar and Stellar Astrophysics · Physics 2025-10-02 Ravi Chaurasiya , 1 Ankala Raja Bayanna , 1 Robertus Erdélyi

The brightness temperature of the radio free-free emission at millimeter range is an effective tool for characterizing the vertical structure of the solar chromosphere. In this paper, we report on the first single-dish observation of a…

Solar and Stellar Astrophysics · Physics 2015-06-24 Kazumasa Iwai , Masumi Shimojo

Identification of the mechanisms responsible for heating the solar chromosphere and corona remains an outstanding problem, one of great relevance to late-type stars as well. There has been tremendous progress in the past decade, largely…

Solar and Stellar Astrophysics · Physics 2019-04-12 Tim Bastian , Bin Chen , Dale Gary , Gregory Fleishman , Lindsay Glesener , Colin Lonsdale , Pascal Saint-Hilaire , Stephen White

A major goal in solar physics has during the last five decades been to find how energy flux generated in the solar convection zone is transported and dissipated in the outer solar layers. Progress in this field has been slow and…

Astrophysics · Physics 2007-05-23 Viggo H. Hansteen , Mats Carlsson , Boris Gudiksen

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