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We show that oppositely directed fluxes of energy and magnetic helicity coexist in the inertial range in fully developed magnetohydrodynamic (MHD) turbulence with small-scale sources of magnetic helicity. Using a helical shell model of MHD…

Plasma Physics · Physics 2015-06-23 Rodion Stepanov , Peter Frick , Irina Mizeva

In the study of relativistic jets one of the key open questions is their interaction with the environment on the microscopic level. Here, we study the initial evolution of both electron$-$proton ($e^{-}-p^{+}$) and electron$-$positron…

By defining an appropriate field line helicity, we apply the powerful concept of magnetic helicity to the problem of global magnetic field evolution in the Sun's corona. As an ideal-magnetohydrodynamic invariant, the field line helicity is…

Solar and Stellar Astrophysics · Physics 2017-07-05 A. R. Yeates , G. Hornig

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

We study the magnetic helicity evolution in neutron stars (NSs). First, we analyze how the surface terms affect the conservation law for the sum of the chiral imbalance of the charged particle densities and the density of the magnetic…

High Energy Astrophysical Phenomena · Physics 2024-01-29 Maxim Dvornikov

We studied 101 flux emergence events ranging from small ephemeral regions to large emerging flux regions which were observed with Hinode Solar Optical Telescope filtergram. We investigated how the total magnetic flux of the emergence event…

Solar and Stellar Astrophysics · Physics 2015-05-28 Kenichi Otsuji , Reizaburo Kitai , Kiyoshi Ichimoto , Kazunari Shibata

We examine a simulation of flux emergence and cancellation, which shows a complex sequence of processes that accumulate free magnetic energy in the solar corona essential for the eruptive events such as coronal mass ejections (CMEs),…

Solar and Stellar Astrophysics · Physics 2015-06-05 Fang Fang , Ward Manchester , William P. Abbett , Bart van der Holst

We carried out a parameter study of interacting disk galaxies with impact parameters ranging from central collisions to weakly interacting scenarios. The orientations of the disks were also varied. In particular, we investigated how…

Astrophysics of Galaxies · Physics 2024-09-18 Simon Selg , Wolfram Schmidt

We analyze the complete chain of effects caused by a solar eruptive event in order to better understand the dynamic evolution of magnetic-field related quantities in interplanetary space, in particular that of magnetic flux and helicity. We…

Solar and Stellar Astrophysics · Physics 2023-01-11 J. K. Thalmann , M. Dumbovic , K. Dissauer , T. Podladchikova , G. Chikunova , M. Temmer , E. Dickson , A. M. Veronig

Using vector magnetograms from the HMI/SDO and a magnetic connectivity-based method, we calculate the instantaneous relative magnetic helicity and free magnetic energy budgets for several days in two solar active regions (ARs), AR11890 and…

Solar and Stellar Astrophysics · Physics 2023-03-29 E. Liokati , A. Nindos , M. K. Georgoulis

Some common properties of helical magnetic fields in decaying and driven turbulence are discussed. These include mainly the inverse cascade that produces fields on progressively larger scales. Magnetic helicity also restricts the evolution…

Astrophysics · Physics 2007-05-23 Axel Brandenburg

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

We consider a scale-invariant helical magnetic field generated during inflation. We show that, if the mean magnetic helicity density of such a field is measured, it can be used to determine a lower bound on the duration of inflation. Upper…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-13 Tina Kahniashvili , Axel Brandenburg , Ruth Durrer , Alexander G. Tevzadze , Winston Yin

Using simulated data-driven three-dimensional resistive MHD simulations of the solar atmosphere, we show that magnetic reconnection can be responsible of the formation of jets with characteristic of Type II spicules. For this, we…

Solar and Stellar Astrophysics · Physics 2018-04-06 J. J. González-Avilés , F. S. Guzmán , V. Fedun , G. Verth , S. Shelyag , S. Regnier

We present the study of SOL2015-03-15 M1.2 flare, revealing acceleration of electrons and plasma heating in the sheared twisted magnetic structure in the polarity inversion line (PIL). The scope is to make the analysis of nonthermal…

Solar and Stellar Astrophysics · Physics 2018-09-19 I. N. Sharykin , I. V. Zimovets , I. I. Myshyakov , N. S. Meshalkina

The kinematic and radiative power of molecular jets is expected to change as a protostar undergoes permanent or episodal changes in the rate at which it accretes. We study here the consequences of evolving jet power on the spatial and…

Astrophysics · Physics 2009-11-07 Alexander Rosen , Michael D. Smith

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

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 extend our recent derivation of the time evolution equations for the energy content of magnetic fields and turbulent motions for incompressible, homogeneous, and isotropic turbulence to include the case of nonvanishing helicity. These…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-14 Andrey Saveliev , Karsten Jedamzik , Guenter Sigl

Magnetic helicity is approximately conserved in resistive MHD models. It quantifies the entanglement of the magnetic field within the plasma. The transport and removal of helicity is crucial in both the dynamo in the solar interior and…

Solar and Stellar Astrophysics · Physics 2020-03-25 Christopher Prior , Gareth Hawkes , Mitch Berger