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A proxy for horizontal electric currents in the solar photosphere was suggested. For a set of evolving active regions (ARs) observed with {\it Solar and Heliospheric Observatory (SOHO)} Michelson Doppler Imager (MDI) in the high resolution…

Astrophysics · Physics 2008-06-11 Valentyna Abramenko

The distribution and evolution of photospheric magnetic field in sunspots, plages and network, and variations in their relative flux content, play key roles in radial velocity (RV) fluctuations observed in Sun-as-a-star spectra.…

Solar and Stellar Astrophysics · Physics 2023-09-12 Anisha Sen , S. P. Rajaguru

Magnetic-field sensing has contributed to the formulation of the plate-tectonics theory, the discovery and mapping of underground structures on Earth, and the study of magnetism in other planets. Filling the gap between space-based and…

Strong, globally-organized magnetic fields are found for a small fraction of O, B, and A stars. At the same time, many theoretical and indirect observational studies suggested ubiquitous presence of weak localized magnetic fields at the…

Solar and Stellar Astrophysics · Physics 2015-06-15 O. Kochukhov , N. Sudnik

With the advent of next generation high resolution telescopes, our understanding of how the magnetic field is organized in the internetwork (IN) photosphere is likely to advance.We aim to evaluate the extent to which we can retrieve…

Solar and Stellar Astrophysics · Physics 2021-10-04 R. J. Campbell , S. Shelyag , C. Quintero Noda , M. Mathioudakis , P. H. Keys , A. Reid

We present high-resolution and multi-line observations of a C2-class solar flare, occurred in NOAA AR 12740 on May 6, 2019. The rise, peak and decay phases of the flare were recorded continuously and quasi-simultaneously in the Ca II K line…

Solar and Stellar Astrophysics · Physics 2021-05-26 Rahul Yadav , C. J. D. Baso , J. de la Cruz Rodr'iguez , F. Calvo , R. Morosin

We investigate the linear correlation coefficient between the intensities at different wavelengths in photospheric and chromospheric spectral lines. Waves that propagate vertically through the stratified solar atmosphere affect different…

Solar and Stellar Astrophysics · Physics 2015-05-14 C. Beck , W. Rammacher

Aims: Changes of the magnetic field and the line-of-sight velocities in the photosphere are being reported for an M-class flare that originated at a $\delta$-spot belonging to active region NOAA 11865. Methods: High-resolution ground-based…

We use coordinated Hinode SOT/EIS observations that include high-resolution magnetograms, chromospheric and TR imaging and TR/coronal spectra in a first test to study how the dynamics of the TR are driven by the highly dynamic photospheric…

The role of magnetic fields in the chromospheric heating problem remains greatly unconstrained. Most theoretical predictions from numerical models rely on a magnetic configuration, field strength and connectivity whose details have not been…

Solar and Stellar Astrophysics · Physics 2020-10-28 R. Morosin , J. de la Cruz Rodriguez , G. J. M. Vissers , R. Yadav

High spatial resolution spectro-polarimetric observation of a decaying spot was observed with the Diffraction Limited Spectro-Polarimeter. The spatial resolution achieved was close to the diffraction limit (0."18) of the Dunn Solar…

Astrophysics · Physics 2008-01-21 K. Sankarasubramanian , H. Hagenaar

The magnetic topology of the solar photosphere in its quietest regions is hidden by the difficulties to disentangle magnetic flux through the resolution element from the field strength of unresolved structures. The observation of spectral…

Astrophysics · Physics 2015-05-13 J. C. Ramirez Velez , A. Lopez Ariste , M. Semel

From previous studies of the effect of primordial magnetic fields on early structure formation, we know that the presence of primordial magnetic fields during early structure formation could induce more perturbations at small scales (at…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Kanhaiya L. Pandey , Shiv K. Sethi

Line intensity mapping (LIM) proposes to efficiently observe distant faint galaxies and map the matter density field at high redshift. Building upon the formalism in the companion paper, we first highlight the degeneracies between cosmology…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-29 Emmanuel Schaan , Martin White

We use SDO/HMI and SOLIS/VSM photospheric magnetic field measurements to model the force-free coronal field above a solar active region, assuming magnetic forces to dominate. We take measurement uncertainties caused by, e.g., noise and the…

Solar and Stellar Astrophysics · Physics 2015-06-05 J. K. Thalmann , A. Pietarila , X. Sun , T. Wiegelmann

Until now, how the magnetic fields in M/X-class flaring active regions (ARs) differ from C-class flaring ARs remains unclear. Here, we calculate the key magnetic field parameters within the area of high photospheric free energy density (HED…

Solar and Stellar Astrophysics · Physics 2024-03-01 Ting Li , Yanfang Zheng , Xuefeng Li , Yijun Hou , Xuebao Li , Yining Zhang , Anqin Chen

Measurement of magnetic fields on the few-hundred-kilometer length scale is significant for a variety of geophysical applications including mapping of crustal magnetism and ocean-circulation measurements, yet available techniques for such…

Atomic Physics · Physics 2009-12-23 J. M. Higbie , S. M. Rochester , B. Patton , R. Holzlöhner , D. Bonaccini Calia , D. Budker

The atomic interstellar medium (ISM) is observed to be full of linear structures that are referred to as "fibers". Fibers exhibit similar properties to linear structures found in molecular clouds known as striations. Suggestive of a similar…

Astrophysics of Galaxies · Physics 2019-03-19 Aris Tritsis , Christoph Federrath , Vasiliki Pavlidou

The observed interaction product of Cosmic Rays (CRs) and Galactic magnetic fields (GMF) is the Galactic synchrotron emission integrated over the line-of-sight (LOS). The GMF strength and morphology and the CR density can be probed by…

Astrophysics of Galaxies · Physics 2020-04-08 I. M. Polderman , M. Haverkorn , T. R. Jaffe

Several studies have correlated observations of impulsive solar activity -- flares and coronal mass ejections (CMEs) -- with the amount of magnetic flux near strong-field polarity inversion lines (PILs) in active regions' photospheric…

Astrophysics · Physics 2007-10-03 B. T. Welsch , Y. Li