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The role of magnetic helicity in astrophysical large-scale dynamos is reviewed and compared with cases where there is no energy supply and an initial magnetic field can only decay. In both cases magnetic energy tends to get redistributed to…

Solar and Stellar Astrophysics · Physics 2009-11-13 Axel Brandenburg

Energetic particle transport in the interplanetary medium is known to be affected by magnetic structures. It has been demonstrated for solar energetic particles in near-Earth orbit studies, and also for the more energetic cosmic rays. In…

This white paper advocates the importance of multi-height measurements of the vector magnetic field in the solar atmosphere. As briefly described in this document, these measurements are critical for addressing some of the most fundamental…

Instrumentation and Methods for Astrophysics · Physics 2022-09-13 L. Bertello , N. Arge , A. G. De Wijn , S. Gosain , C. Henney , K. D. Leka , J. Linker , Y. Liu , J. Luhmann , P. J. Macniece , G. Petrie , A. Pevtsov , A. A. Pevtsov

Modern observatories have revealed the ubiquitous presence of magnetohydrodynamic waves in the solar corona. The propagating waves (in contrast to the standing waves) are usually originated in the lower solar atmosphere which makes them…

Solar and Stellar Astrophysics · Physics 2021-11-24 D. Banerjee , S. Krishna Prasad , V. Pant , J. A. McLaughlin , P. Antolin , N. Magyar , L. Ofman , H. Tian , T. Van Doorsselaere , I. De Moortel , T. Wang

Helioseismology revealed an increase in the rotation rate with depth just beneath the solar surface. The relative magnitude of the radial shear is almost constant with latitude. This rotational state can be interpreted as a consequence of…

Solar and Stellar Astrophysics · Physics 2016-06-01 Leonid Kitchatinov

The role of the different helical components of the magnetic and velocity fields in the inverse spectral transfer of magnetic helicity is investigated through Fourier shell-to-shell transfer analysis. Both magnetic helicity and energetic…

Plasma Physics · Physics 2021-07-07 Jean-Mathieu Teissier , Wolf-Christian Müller

Oscillations detected on the solar surface provide a unique possibility for investigations of the interior properties of a star. Through major observational efforts, including extensive observations from space, as well as development of…

Astrophysics · Physics 2008-11-26 J. Christensen-Dalsgaard

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

Using a recently proposed nonlinear force-free method designed for single vector magnetograms of solar active regions we calculate the instantaneous free magnetic energy and relative magnetic helicity budgets in 162 vector magnetograms…

Solar and Stellar Astrophysics · Physics 2015-06-11 Kostas Tziotziou , Manolis K. Georgoulis , Nour-Eddine Raouafi

Coronal mass ejections (CMEs) are magnetized plasma systems with highly complex magnetic topology and evolution. Methods developed to assess their magnetic configuration have primarily focused on reconstructing three-dimensional…

Space Physics · Physics 2024-08-09 Nada Al-Haddad , Mitchell Berger

The magnetic field within a few hundred parsecs of the center of the Galaxy is an essential component of any description of that region. The field has several pronounced observational manifestations: 1) morphological structures such as…

Astrophysics · Physics 2007-05-23 Mark Morris

The most geoeffective solar drivers are magnetic clouds - a subclass of coronal mass ejections (CME's) distinguished by the smooth rotation of the magnetic field inside the structure. The portion of CME's that are magnetic clouds is maximum…

Astrophysics · Physics 2007-05-23 K. Georgieva , B. Kirov , E. Gavruseva , J. Javaraiah

Aims. The main aim of this work is to study the evolution of the recently introduced relative helicity of the magnetic polarity inversion line (PIL) in a magnetohydrodynamics simulation. Methods. The simulation used is a typical flux…

Solar and Stellar Astrophysics · Physics 2024-09-05 K. Moraitis , V. Archontis , G. Chouliaras

The relative magnetic helicity is a quantity that is often used to describe the level of entanglement of non-isolated magnetic fields, such as the magnetic field of solar active regions.The aim of this paper is to investigate how different…

Solar and Stellar Astrophysics · Physics 2018-08-15 Francesco P. Zuccarello , Etienne Pariat , Gherardo Valori , Luis Linan

We explore the impact of magnetic helicity conservation on the mean-field solar dynamo using the axisymmetric dynamo model which includes the subsurface shear. Our results support the recent findings by Hubbard & Brandenburg (2012), who…

Solar and Stellar Astrophysics · Physics 2015-06-12 V. V. Pipin , D. D. Sokoloff , H. Zhang , K. M. Kuzanyan

Magnetic flux ropes are characterized by coherently twisted magnetic field lines, which are ubiquitous in magnetized plasmas. As the core structure of various eruptive phenomena in the solar atmosphere, flux ropes hold the key to…

Solar and Stellar Astrophysics · Physics 2021-06-10 Rui Liu

Magnetic fields are usually observed in the quiet Sun as small-scale elements that cover the entire solar surface (the `salt and pepper' patterns in line-of-sight magnetograms). By using 3D radiative MHD numerical simulations we find that…

Solar and Stellar Astrophysics · Physics 2015-08-19 I. N. Kitiashvili , A. G. Kosovichev , N. N. Mansour , A. A. Wray

Magnetic flux fills the heliosphere, expands outward from the solar corona, and is fundamentally related to the structure and dynamics of the solar corona and solar wind. Open magnetic flux and the fast wind are thought to originate from…

Solar and Stellar Astrophysics · Physics 2026-04-13 Roberto Lionello , Cooper Downs , Emily I. Mason , Jon A. Linker , Pete Riley , Mathew J. Owens

The relative importance of the helicity and cross-helicity electromotive dynamo effects for self-sustained magnetic field generation by chaotic thermal convection in rotating spherical shells is investigated as a function of shell…

Fluid Dynamics · Physics 2020-12-18 Luis Silva , Parag Gupta , David MacTaggart , Radostin D. Simitev

The coupling between small and large scale structures and processes on the Sun and in the heliosphere is important in the relation to the global magnetic configuration. Thin heliospheric current sheets play the leading role in this respect.…

Solar and Stellar Astrophysics · Physics 2012-12-24 Igor Veselovsky , Olga Panasenco
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