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The evolution of nonpotential characteristics of magnetic fields in AR 5747 is presented using Mees Solar Observatory magnetograms taken on Oct. 20, 1989 to Oct. 22, 1989. The active region showed such violent flaring activities during the…

Astrophysics · Physics 2007-05-23 Y. -J. Moon , H. S. Yun , G. S. Choe , Y. D. Park , D. L. Mickey

The extreme space weather conditions resulting from high energetic events likes solar flares and Coronal Mass Ejections (CMEs) demand for reliable space weather forecasting. The magnetic flux tubes while rising through the convection zone…

Solar and Stellar Astrophysics · Physics 2022-10-19 B Lekshmi , Kiran Jain , Rudolf W. Komm , Dibyendu Nandy

We analyse the asymptotic growth of the error for Hamiltonian flows due to small random perturbations. We compare the forward error with the reversibility error, showing their equivalence for linear flows on a compact phase space. The…

Here, we analyzed magnetic elements of the solar active regions (ARs) observed in the line-of-sight magnetograms (the 6173 \AA~Fe \small{I} line) recorded with the Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager (HMI). The…

Solar and Stellar Astrophysics · Physics 2021-09-28 M. A. Moradhaseli , M. Javaherian , N. Fathalian , H. Safari

We present an experimental study of the statistical properties of millimeter-size spheres floating on the surface of a turbulent flow. The flow is generated in a layer of liquid metal by an electromagnetic forcing. By using two magnet…

Fluid Dynamics · Physics 2016-07-04 Pablo Gutiérrez , Sébastien Aumaître

Context: Giant-cell convection is believed to be an important component of solar dynamics. For example, it is expected to play a crucial role in maintaining the Sun's differential rotation. Aims: We re-examine early reports of giant…

Solar and Stellar Astrophysics · Physics 2021-01-04 Chris S. Hanson , Thomas L. Duvall , Aaron C. Birch , Laurent Gizon , Katepalli R. Sreenivasan

We investigate how the magnetic loop length of solar flares relates to the timing between their thermal and nonthermal emission signatures. Our study analyzes a sample of 96 C-, M-, and X-class flares observed between 2013 and 2015 with…

Solar and Stellar Astrophysics · Physics 2026-02-24 S. M. Perriyil , S. S. Sadangaya , C. G. Giménez de Castro , P. J. A. Simões

Understanding the nature and evolution of the photospheric helicity flux transfer is a key to reveal the role of magnetic helicity in coronal dynamics of solar active regions. Using SDO/HMI photospheric vector magnetograms and the derived…

Solar and Stellar Astrophysics · Physics 2017-01-11 P. Vemareddy , P. Démoulin

Robust velocity and position estimation is crucial for autonomous robot navigation. The optical flow based methods for autonomous navigation have been receiving increasing attentions in tandem with the development of micro unmanned aerial…

Robotics · Computer Science 2018-12-06 Chen Wang , Tete Ji , Thien-Minh Nguyen , Lihua Xie

For a freely evolving granular fluid, the buildup of spatial correlations in density and flow field is described using fluctuating hydrodynamics. The theory for incompressible flows is extended to the general, compressible case, including…

Statistical Mechanics · Physics 2009-10-30 T. P. C. van Noije , M. H. Ernst , R. Brito

The motions of small-scale magnetic flux elements in the solar photosphere can provide some measure of the Lagrangian properties of the convective flow. Measurements of these motions have been critical in estimating the turbulent diffusion…

Solar and Stellar Astrophysics · Physics 2018-02-27 Piyush Agrawal , Mark P. Rast , Milan Gosic , Luis R. Bellot Rubio , Matthias Rempel

The absence of self averaging in mesoscopic systems is a consequence of long-range intensity correlation. Microwave measurements suggest and diagrammatic calculations confirm that the correlation function of the normalized intensity with…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 P. Sebbah , B. Hu , A. Z. Genack , R. Pnini , B. Shapiro

The magnetic non-potentiality is important for understanding flares and other solar activities in active regions (ARs). Five non-potential parameters, i.e., electric current, current helicity, source field, photospheric free energy, and…

Solar and Stellar Astrophysics · Physics 2015-06-11 Qiao Song , Jun Zhang , Shuhong Yang , Yang Liu

We investigate the time autocorrelation of the molecular magnetization $M(t)$ for three classes of magnetic molecules (antiferromagnetic rings, grids and nanomagnets), in contact with the phonon heat bath. For all three classes, we find…

Materials Science · Physics 2009-11-10 P. Santini , S. Carretta , E. Liviotti , G. Amoretti , P. Carretta , M. Filibian , A. Lascialfari , E. Micotti

This chapter is build from three 1.5 hours lectures given in Udine in april 2018 on various aspects of Earth's core dynamics. The chapter starts with a short historical note on the discovery of Earth's magnetic field and core (section 1).…

Geophysics · Physics 2019-05-28 Renaud Deguen , Marine Lasbleis

Fast radio bursts (FRBs) are energetic millisecond phenomena in radio band. Polarimetric studies of repeating FRBs indicate that many of these sources occupy extreme and complex magneto-ionized environments. Recently, a frequency-dependent…

High Energy Astrophysical Phenomena · Physics 2023-09-14 Wan-Jin Lu , Zhen-Yin Zhao , F. Y. Wang , Z. G. Dai

In the standard model of solar flares, a large-scale reconnection current sheet is postulated as the central engine for powering the flare energy release and accelerating particles. However, where and how the energy release and particle…

We study coherent structures in solar photospheric flows in a plage in the vicinity of the active region AR 10930 using the horizontal velocity data derived from Hinode/SOT magnetograms. Eulerian and Lagrangian coherent structures are…

We present a study of wave processes occurring in solar active region NOAA 11131 on 2010 December 10, captured by the Solar Dynamics Observatory in the 1600A, 304A, and 171A channels. For spectral analysis we employed pixelised wavelet…

Solar and Stellar Astrophysics · Physics 2021-01-20 Robert Sych , David B. Jess , Jiangtao Su

Aims: We investigate the temporal evolution of magnetic flux emergence in the quiet Sun atmosphere close to disk center. Methods: We combine high-resolution SoHO/MDI magnetograms with TRACE observations taken in the 1216 {\AA} channel in…

Solar and Stellar Astrophysics · Physics 2015-06-16 P. Gömöry , H. Balthasar , K. G. Puschmann