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Related papers: Temporal evolution of short-lived penumbral microj…

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Hot luminous stars show a variety of phenomena in their photospheres and winds which still lack clear physical explanation. Among these phenomena are photospheric turbulence, line profile variability (LPV), non-thermal emission, non-radial…

Solar and Stellar Astrophysics · Physics 2015-05-30 Matteo Cantiello , Jonathan Braithwaite

Multi-frequency (4.6, 5, 5.5, 8, 8.8, 13, 15, 22 & 43 GHz) polarization observations of 6 "blazars" were obtained on the American Very Long Baseline Array (VLBA) over a 24-hr period on 2 July 2006. Observing at several frequencies,…

Astrophysics · Physics 2009-11-13 Shane P. O'Sullivan , Denise C. Gabuzda

Context. Magnetic bright points (MBPs) are one of the smallest manifestations of the magnetic field in the solar atmosphere and are observed to extend from the photosphere up to the chromosphere. As such, they represent an excellent feature…

Solar and Stellar Astrophysics · Physics 2024-09-19 Arthur Berberyan , Peter H. Keys , David B. Jess , Damian J. Christian

Outflows driven by active galactic nuclei (AGN) are seen in numerous compact sources; however, it has remained unclear how to distinguish between the driving mechanisms, such as winds and jets. Therefore, our study aims to offer…

High Energy Astrophysical Phenomena · Physics 2024-08-02 Moun Meenakshi , Dipanjan Mukherjee , Gianluigi Bodo , Paola Rossi , Chris M. Harrison

Studies on small-scale jets' formation, propagation, evolution, and role, such as type I and II spicules, mottles, and fibrils in the lower solar atmosphere's energetic balance, have progressed tremendously thanks to the combination of…

A sunspot penumbra is observationally examined to reveal properties of small-scale flow structures and how they are related to the filamentary magnetic structures and the Evershed flow. We also study how the photospheric dynamics is related…

Solar and Stellar Astrophysics · Physics 2015-05-19 Y. Katsukawa , J. Jurcak

The fine-structure of magnetic field of a sunspot penumbra in the upper chromosphere is to be explored and compared to that in the photosphere. High spatial resolution spectropolarimetric observations were recorded with the 1.5-meter GREGOR…

We study the evolution of galactic magnetic fields using 3D smoothed particle magnetohydrodynamics (SPMHD) simulations of galaxies with an imposed spiral potential. We consider the appearance of reversals of the field, and amplification of…

Astrophysics of Galaxies · Physics 2016-09-07 C. L. Dobbs , D. J. Price , A. R. Pettitt , M. R. Bate , T. Tricco

During eruptive flares, vector magnetograms show increasing horizontal magnetic field and downward Lorentz force in the Sun's photosphere around the polarity-inversion line. Such behavior has often been associated with the implosion…

Solar and Stellar Astrophysics · Physics 2019-06-05 Krzysztof Barczynski , Guillaume Aulanier , Sophie Masson , Michael S. Wheatland

Gamma-ray bursts (GRBs) have been widely argued to originate from binary compact object mergers or core collapses of massive stars. Jets from these systems may have two components, an inner, narrow sub-jet and an outer, wider sub-jet. Such…

High Energy Astrophysical Phenomena · Physics 2018-06-27 Mi-Xiang Lan , Xue-Feng Wu , Zi-Gao Dai

We study the evolution of the field on the surface of proto-neutron stars in the immediate aftermath of stellar core collapse by analyzing the results of self-consistent, axisymmetric simulations of the cores of rapidly rotating high-mass…

High Energy Astrophysical Phenomena · Physics 2018-01-17 Martin Obergaulinger , Miguel-Ángel Aloy

Jets, whatever small (e.g. spicules) or large (e.g. macrospicules) their size, may play a key role in momentum and energy transport from photosphere to chromosphere and at least to the low corona. Here, we investigate the properties of…

Solar and Stellar Astrophysics · Physics 2017-06-02 T. S. Kiss , N. Gyenge , R. Erdelyi

Velocity oscillations in sunspot umbrae have been measured simultaneously in two spectral lines: the photospheric Silicon I 10827 A line and the chromospheric Helium I 10830 A multiplet. From the full Stokes inversion of temporal series of…

Astrophysics · Physics 2009-11-13 Rebecca Centeno , Manuel Collados , Javier Trujillo Bueno

Determination of solar magnetic fields with a spatial resolution set by the diffraction limit of a telescope is difficult because the time required to measure the Stokes vector with sufficient signal-to-noise is long compared to the solar…

Solar and Stellar Astrophysics · Physics 2024-05-08 Jaime de la Cruz Rodríguez , Jorrit Leenaarts

Sunspot umbrae show a change in the dominant period of their oscillations from five minutes in the photosphere to three minutes in the chromosphere. In this paper, we explore the two most popular models proposed to explain the three-minute…

Solar and Stellar Astrophysics · Physics 2019-07-24 T. Felipe

The evolution of the spectral energy distribution during flares constrains models of particle acceleration in blazar jets. The archetypical blazar BL Lac provided a unique opportunity to study spectral variations during an extended strong…

High Energy Astrophysical Phenomena · Physics 2023-03-15 S. Agarwal , B. Banerjee , A. Shukla , J. Roy , S. Acharya , B. Vaidya , V. R. Chitnis , S. M. Wagner , K. Mannheim , M. Branchesi

Magnetic fields on the order of 100 $\mu$G observed in young supernova remnants cannot be amplified by shock compression alone. To investigate the amplification caused by turbulent dynamo, we perform three-dimensional MHD simulations of the…

Astrophysics of Galaxies · Physics 2022-12-28 Yue Hu , Siyao Xu , James M. Stone , Alex Lazarian

We present a comprehensive statistical study of the radial evolution of solar wind turbulence near Mercury's orbit using long-term magnetic field measurements from the MESSENGER mission. Owing to Mercury's highly elliptical orbit and the…

Self-generated magnetic fields are commonly produced in high-power laser-plasma interactions. These fields can inhibit plasma heat-flow which makes them important in inertial fusion and controlled laboratory astrophysics experiments. In…

During solar flares, magnetic energy can be converted into electromagnetic radiation from radio waves to $\gamma$ rays. Enhancements in the continuum at visible wavelengths give rise to white-light flares, as well as continuum enhancements…