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The observed solar photospheric magnetic fields and Doppler velocities are frequently used to quantify the Poynting flux and helicity flux. Multiple methods have been developed for this purpose, but their estimates of the Poynting flux and…

Solar and Stellar Astrophysics · Physics 2026-04-20 Jiayi Liu , Xudong Sun , Peter W. Schuck , Lars K. S. Daldorff

Magnetic helicity is a physical quantity that describes field topology. It is also a conserved quantity as Berger in 1984 demonstrated that the total magnetic helicity is still conserved in the corona even when there is a fast magnetic…

Solar and Stellar Astrophysics · Physics 2015-06-12 Mei Zhang

We demonstrate that the current helicity observed in solar active regions traces the magnetic helicity of the large-scale dynamo generated field. We use an advanced 2D mean-field dynamo model with dynamo saturation based on the evolution of…

Solar and Stellar Astrophysics · Physics 2015-05-30 H. Zhang , D. Moss , N. Kleeorin , K. Kuzanyan , I. Rogachevskii , D. Sokoloff , Y. Gao , H. Xu

The injection of magnetic helicity into the heliosphere during solar cycle 24 and the early phase of cycle 25 has been calculated based on the analysis of a series of synoptic magnetic charts. During the cycle, the injected magnetic…

Solar and Stellar Astrophysics · Physics 2025-07-28 H. Q. Zhang , S. B. Yang , K. M. Kuzanyan , Axel Brandenburg , H. Q. Xu , D. D. Sokoloff

With the development of new instrumentation providing measurements of solar photospheric vector magnetic fields, we need to develop our understanding of the effects of current density on coronal magnetic field configurations. The object is…

Astrophysics · Physics 2009-11-13 S. Regnier , E. R. Priest

Patsourakos et al. (Astrophys. J. 817, 14, 2016) and Patsourakos and Georgoulis (Astron. Astrophys. 595, A121, 2016) introduced a method to infer the axial magnetic field in flux-rope coronal mass ejections (CMEs) in the solar corona and…

Solar and Stellar Astrophysics · Physics 2017-07-19 S. Patsourakos , M. K. Georgoulis

Kinetic helicity is a fundamental characteristics of astrophysical turbulent flows. It is not only responsible for the generation of large-scale magnetic fields in the Sun, stars, and spiral galaxies, but it also affects turbulent diffusion…

Fluid Dynamics · Physics 2025-05-15 Igor Rogachevskii , Nathan Kleeorin , Axel Brandenburg

Magnetic helicity (MH) is a measure of twist and shear of magnetic field. MH is injected in the active region (AR) corona through photospheric footpoint motions causing twisted and sheared magnetic fields. From the conservation property of…

Solar and Stellar Astrophysics · Physics 2021-09-01 P. Vemareddy

Potential field extrapolations are widely used as minimum-energy models for the Sun's coronal magnetic field. As the reference to which other magnetic fields are compared, they have -- by any reasonable definition -- no global (signed)…

Solar and Stellar Astrophysics · Physics 2020-08-12 A. R. Yeates

Aims. Solar active regions (ARs), which are formed by flux emergence, serve as the primary sources of solar eruptions. However, the specific physical mechanism that governs the emergence process and its relationship with flare productivity…

Solar and Stellar Astrophysics · Physics 2024-03-28 Zheng Sun , Ting Li , Quan Wang , Shangbin Yang , Mei Zhang , Yajie Chen

Solar flares and coronal mass ejections are the largest energy release phenomena in the current solar system. They cause drastic enhancements of electromagnetic waves of various wavelengths and sometimes eject coronal material into the…

Solar and Stellar Astrophysics · Physics 2022-04-14 Shin Toriumi , Sung-Hong Park

Observation of solar-like stars show a clear relation between X-ray emission and their rotation. Higher stellar rotation can lead to a larger magnetic helicity production in stars. We aim to understand the relation between magnetic helicity…

Solar and Stellar Astrophysics · Physics 2019-10-17 Jörn Warnecke , Hardi Peter

Using time-sequence vector magnetic field and coronal observations from \textit{Solar Dynamics Observatory}, we report the observations of the magnetic field evolution and coronal activity in four emerging active regions (ARs). The ARs…

Solar and Stellar Astrophysics · Physics 2022-08-24 P. Vemareddy

We study the effect of turbulent drift of a large-scale magnetic field that results from the interaction of helical convective motions and differential rotation in the solar convection zone. The principal direction of the drift corresponds…

Solar and Stellar Astrophysics · Physics 2015-06-05 V. V. Pipin

We propose a novel approach to reconstruct the surface magnetic helicity density on the Sun or sun-like stars. The magnetic vector potential is determined via decomposition of vector magnetic field measurements into toroidal and poloidal…

Solar and Stellar Astrophysics · Physics 2019-06-12 Valery V. Pipin , Alexei A. Pevtsov , Yang Liu , Alexander G. Kosovichev

The structure of electric current and magnetic helicity in the solar corona is closely linked to solar activity over the 11-year cycle, yet is poorly understood. As an alternative to traditional current-free "potential field"…

Solar and Stellar Astrophysics · Physics 2015-05-18 A. R. Yeates , J. A. Constable , P. C. H. Martens

Using the 135-second cadence of the photospheric vector data provided by the Helioseismic and Magnetic Imager telescope on board the Solar Dynamic Observatory, we examined the time-evolution of magnetic helicity fluxes across the…

Solar and Stellar Astrophysics · Physics 2018-10-17 Yi Bi , Ying D Liu , Yanxiao Liu , Jiayan Yang , Zhe Xu , Kaifan JI

Our aim is to study the photospheric flux distribution of a twisted flux tube that emerges from the solar interior. We also report on the eruption of a new flux rope when the emerging tube rises into a pre-existing magnetic field in the…

Solar and Stellar Astrophysics · Physics 2010-03-12 V. Archontis , A. W. Hood

In this review many of the well known tools for the analysis of Complex systems are used in order to study the global coupling of the turbulent convection zone with the solar atmosphere where the magnetic energy is dissipated explosively.…

Solar and Stellar Astrophysics · Physics 2016-11-03 Loukas Vlahos , Heinz Isliker

This study identifies the solar origins of magnetic clouds that are observed at 1 AU and predicts the helical handedness of these clouds from the solar surface magnetic fields. We started with the magnetic clouds listed by the Magnetic…

Solar and Stellar Astrophysics · Physics 2018-11-09 Roger K. Ulrich , Pete Riley , T. Tran