Results 1 to 10 of about 12,497 (208)

Primordial helical magnetic fields from inflation? [PDF]

Physical Review D, 2022
24+15 pages, 6 figures, 5 appendices,new references added, match the published ...
Alireza Talebian, Amin Nassiri-Rad, Hassan Firouzjahi   +2 more
openalex   +4 more sources

Field linkage and magnetic helicity density

Monthly Notices of the Royal Astronomical Society, 2021
ABSTRACT The helicity of a magnetic field is a fundamental property that is conserved in ideal MHD. It can be explored in the stellar context by mapping large-scale magnetic fields across stellar surfaces using Zeeman–Doppler imaging. A recent study of 51 stars in the mass range 0.1–1.34 M⊙ showed that the photospheric magnetic helicity ...
M. Jardine, Kristin Lund, A. J. B. Russell, J.‐F. Donati, R. Farès, C. P. Folsom, S. V. Jeffers, S. C. Marsden, J. Morin, Petit Pascal, Victor See   +10 more
openalex   +6 more sources

Magnetic helicity generation from the cosmic axion field [PDF]

Physical Review D, 2005
The coupling between a primordial magnetic field and the cosmic axion field generates a helical component of the magnetic field around the time in which the axion starts to oscillate. If the energy density of the seed magnetic field is comparable to the energy density of the universe at that time, then the resulting magnetic helicity is about |H_B ...
Leonardo Campanelli, Maurizio Giannotti
openalex   +3 more sources

Evidence for Helical Magnetic Fields Associated with AGN Jets and the Action of a Cosmic Battery [PDF]

Galaxies, 2018
Theoretical models for the electromagnetic launching of astrophysical jets have long indicated that this process should generate helical magnetic fields, which should then propagate outward with the jet plasma.
Denise Gabuzda
doaj   +2 more sources

Relative magnetic field line helicity [PDF]

Astronomy & Astrophysics, 2019
Context. Magnetic helicity is an important quantity in studies of magnetized plasmas as it provides a measure of the geometrical complexity of the magnetic field in a given volume. A more detailed description of the spatial distribution of magnetic helicity is given by the field line helicity, which expresses the amount of helicity associated to ...
K. Moraitis, E. Pariat, G. Valori, K. Dalmasse   +3 more
openalex   +6 more sources

Observational Properties of Helical Magnetic Fields [PDF]

Symposium - International Astronomical Union, 1993
The model of the polarized emission from a spiral galaxy similar to M31, containing helically twisted magnetic field has been constructed. Helical magnetic field was found to cause a specific asymmetry of the distribution of the polarized brightness of the galactic disk.
M. Urbaník, K. Otmianowska‐Mazur
openalex   +2 more sources

Fabrication of anisotropic magnetic helical microswimmers utilizing Spirulina platensis templates and their integration with Janus PCL/Chitosan nanoparticles [PDF]

Scientific Reports
Magnetically-actuated microswimmers are promising candidates for controlled cargo transport and microscale manipulation; however, achieving efficient, fuel-free propulsion with precisely defined anisotropic structures remains a significant fabrication ...
Mahdieh Jahani, Sepideh Khoee, Masoud Mirmasoumi   +2 more
doaj   +2 more sources

Microscopic Processes in Global Relativistic Jets Containing Helical Magnetic Fields: Dependence on Jet Radius

Galaxies, 2017
In this study, we investigate the interaction of jets with their environment at a microscopic level, which is a key open question in the study of relativistic jets.
Ken-Ichi Nishikawa, Yosuke Mizuno, Jose L. Gómez, Ioana Duţan, Athina Meli, Charley White, Jacek Niemiec, Oleh Kobzar, Martin Pohl, Asaf Pe’er, Jacob Trier Frederiksen, Åke Nordlund, Helene Sol, Philip E. Hardee, Dieter H. Hartmann   +14 more
doaj   +2 more sources

Magnetized relativistic jets and helical magnetic fields

Astronomy & Astrophysics, 2021
This is the second of a series of two papers that deepen our understanding of the transversal structure and the properties of recollimation shocks of axisymmetric, relativistic, superfast magnetosonic, overpressured jets. They extend previous work that characterized these properties in connection with the dominant type of energy (internal, kinetic, or ...
Fuentes, A., Torregrosa, I., Martí, J. M., Gómez Fernández, J. L., Perucho, M.   +4 more
openaire   +4 more sources

Helical magnetic fields from Riemann coupling [PDF]

Physical Review D, 2020
We study the inflationary generation of helical magnetic fields from the Riemann coupling with the electromagnetic field. Most models in the literature introduce non-minimal coupling to the electromagnetic fields with a scalar field, hence, breaking the conformal invariance.
Ashu Kushwaha, S. Shankaranarayanan
openaire   +2 more sources