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One prominent feature of solar cycle is its irregular variation in its cycle strength, making it challenging to predict the amplitude of the next cycle. Studies show that fluctuations and nonlinearity in generating poloidal field throughout…

Solar and Stellar Astrophysics · Physics 2025-11-10 Bidisha Dey , Anu Sreedevi , Bidya Binay Karak

Filaments and coronal holes, two principal features observed in the solar corona are sources of space weather variations. Filament formation is closely associated with polarity inversion lines (PIL) on the solar photosphere which separate…

Solar and Stellar Astrophysics · Physics 2018-11-28 Rakesh Mazumder , Prantika Bhowmik , Dibyendu Nandy

Context: Solar active regions (ARs) are key manifestations of the Sun's magnetic activity, displaying diverse spatial and temporal characteristics. Their formation and evolution play a crucial role in understanding the solar dynamo and…

Solar and Stellar Astrophysics · Physics 2025-08-06 M. Švanda , J. Jurčák , M. Schmassmann

Using the polar vector magnetic field data observed by Hinode from 2012 to 2021, we study the long-term variations of the magnetic flux, the flux proportion of different polarities, and the magnetic inclination with respect to the local…

Solar and Stellar Astrophysics · Physics 2025-09-25 Shuhong Yang , Chunlan Jin , Qiao Song , Yuzong Zhang , Yin Li , Yijun Hou , Ting Li , Guiping Zhou , Yuanyong Deng , Jingxiu Wang

A fraction of solar active regions are observed to have current helicity of a sign that contradicts the polarity law for magnetic helicity; this law corresponds to the well-known Hale polarity law for sunspots. A significant excess of…

Astrophysics · Physics 2009-11-11 D. Sokoloff , S. D. Bao , N. Kleeorin , K. Kuzanyan , D. Moss , I. Rogachevskii , D. Tomin , H. Zhang

Solar active regions show a wide variety of oscillatory phenomena. The presence of the magnetic field leads to the appearance of several wave modes, whose behavior is determined by the sunspot thermal and magnetic structure. We aim to study…

Solar and Stellar Astrophysics · Physics 2019-01-09 T. Felipe , C. Kuckein , E. Khomenko , I. Thaler

We present the first far infrared (FIR) dust emission polarization map covering the full extent Milky Way's Central molecular zone (CMZ). The data, obtained with the PILOT balloon-borne experiment, covers the Galactic Center region…

Although the Sun's polar magnetic fields are thought to provide important clues for understanding the 11-year sunspot cycle, including the observed variations of its amplitude and period, the current database of high-quality polar-field…

Solar and Stellar Astrophysics · Physics 2013-03-05 Andrés Muñoz-Jaramillo , Neil R. Sheeley, , Jie Zhang , Edward E. DeLuca

This research work is based on the study of the longitudinal distribution of the most active sunspot zones on the photosphere. Sunspot data has been analyzed for 12 solar cycles (cycles 12-23) separately for northern and southern…

Solar and Stellar Astrophysics · Physics 2009-09-17 Abdul Malik , Martin Bohm

Photospheric magnetic fields are studied using synoptic maps from 1976 to 2003 produced at the National Solar Observatory, Kitt Peak (NSO/KP). Synoptic maps were averaged over the time interval of nearly three solar cycles (Solar Cycles…

Solar and Stellar Astrophysics · Physics 2016-04-08 E. S. Vernova , M. I. Tyasto , D. G. Baranov

The umbral regions of sunspots and pores in the solar photosphere are generally dominated by $3$~mHz oscillations, which are due to $p$-modes penetrating the magnetic region. In these locations, wave power is also significantly reduced with…

In this paper we provide clear direct evidence of multiple concurrent higher order magnetohydrodynamic (MHD) modes in circular and elliptical sunspots by applying both Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition…

Solar and Stellar Astrophysics · Physics 2022-04-06 A. B. Albidah , V. Fedun , A. A. Aldhafeeri , I. Ballai , W. Brevis , D. B. Jess , J. Higham , M. Stangalini , S. S. A. Silva , G. Verth

A study of the unbalanced magnetic polarity distribution of 70 coronal holes was performed. Data from the Helioseismic and Magnetic Imager (HMI) were used to examine the photospheric line-of-sight magnetic field ($B_{\mathrm{LOS}}$) beneath…

Solar and Stellar Astrophysics · Physics 2026-02-12 Khagendra Katuwal , R. T. James McAteer

The distributions of sunspot longitude at first appearance and at disappearance display an east-west asymmetry that results from a reduction in visibility as one moves from disk centre to the limb. To first order, this is explicable in…

Solar and Stellar Astrophysics · Physics 2011-08-23 Fraser Watson , Lyndsay Fletcher , Silvia Dalla , Stephen Marshall

We study the magnetic flux carried by pores located outside active regions with sunspots and investigate their possible contribution to the reversal of the global magnetic field of the Sun. We find that they contain a total flux of…

Solar and Stellar Astrophysics · Physics 2016-02-10 M. Svanda , A. S. Brun , Th. Roudier , L. Jouve

Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim to understand the magnetic properties that govern such flares and eruptions, we systematically survey all flare…

Solar and Stellar Astrophysics · Physics 2017-01-11 Shin Toriumi , Carolus J. Schrijver , Louise K. Harra , Hugh Hudson , Kaori Nagashima

Sunspots are the most important indicator of the magnetic activity on the solar surface during a cycle. Every sunspot group is formed and shaped by the magnetic field of the Sun. Hence, the magnetic field intensity shows itself as the size…

Instrumentation and Methods for Astrophysics · Physics 2018-12-12 Hikmet Çakmak

Dust polarization observations from the Submillimeter Array (SMA) and the Caltech Submillimeter Observatory (CSO) are analyzed with the goal of providing a general tool to interpret the role of the magnetic field in molecular clouds.…

Astrophysics of Galaxies · Physics 2015-06-17 Patrick M. Koch , Ya-Wen Tang , Paul T. P. Ho

For groups of photospheric magnetic fields differing in strength the time averaged synoptic maps were obtained on the basis of the National Solar Observatory Kitt Peak data (1976-2003). The latitudinal profiles of magnetic field fluxes were…

Solar and Stellar Astrophysics · Physics 2018-03-21 Elena Vernova , Marta Tyasto , Dmitrii Baranov

We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated…

Solar and Stellar Astrophysics · Physics 2015-06-15 G. J. D. Petrie