scholarly journals Magnetic-field generation by the ablative nonlinear Rayleigh–Taylor instability

2014 ◽  
Vol 81 (2) ◽  
Author(s):  
Philip M. Nilson ◽  
L. Gao ◽  
I. V. Igumenshchev ◽  
G. Fiksel ◽  
R. Yan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Atmospheric Pressure ◽  
Large Scale ◽  
Taylor Instability ◽  
Magnetic Field Generation ◽  
Field Generation ◽  
Rayleigh Taylor Instability ◽  
Astrophysical Flows ◽  
Rt Instability

Experiments reporting magnetic-field generation by the ablative nonlinear Rayleigh–Taylor (RT) instability are reviewed. The experiments show how large-scale magnetic fields can, under certain circumstances, emerge and persist in strongly driven laboratory and astrophysical flows at drive pressures exceeding one million times atmospheric pressure.

scholarly journals Magnetic Field Generation by the Rayleigh-Taylor Instability in Laser-Driven Planar Plastic Targets

2012 ◽  
Vol 109 (11) ◽  
Author(s):  
L. Gao ◽  
P. M. Nilson ◽  
I. V. Igumenschev ◽  
S. X. Hu ◽  
J. R. Davies ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Taylor Instability ◽  
Magnetic Field Generation ◽  
Field Generation ◽  
Rayleigh Taylor Instability

scholarly journals Stationary Turbulent Dynamo as Spontaneous Symmetry Breaking

1993 ◽  
Vol 157 ◽  
pp. 237-241
Author(s):  
M. Hnatich
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Large Scale ◽  
Magnetic Field Generation ◽  
Field Generation ◽  
Motion Energy ◽  
Turbulent Dynamo ◽  
Large Scale Magnetic Field

The large-scale magnetic field generation by the turbulent motion energy, known as turbulent dynamo [1], is perspective candidate to explain the observed stationary magnetic fields of cosmic objects.

scholarly journals An 84-μG Magnetic Field in a Galaxy at Z=0.692?

2008 ◽  
Vol 4 (S254) ◽  
pp. 95-96
Author(s):  
Arthur M. Wolfe ◽  
Regina A. Jorgenson ◽  
Timothy Robishaw ◽  
Carl Heiles ◽  
Jason X. Prochaska
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Faraday Rotation ◽  
Large Scale ◽  
Dynamo Model ◽  
Magnetic Field Generation ◽  
Interstellar Gas ◽  
Splitting Technique ◽  
Average Value ◽  
The Magnetic Field

AbstractThe magnetic field pervading our Galaxy is a crucial constituent of the interstellar medium: it mediates the dynamics of interstellar clouds, the energy density of cosmic rays, and the formation of stars (Beck 2005). The field associated with ionized interstellar gas has been determined through observations of pulsars in our Galaxy. Radio-frequency measurements of pulse dispersion and the rotation of the plane of linear polarization, i.e., Faraday rotation, yield an average value B ≈ 3 μG (Han et al. 2006). The possible detection of Faraday rotation of linearly polarized photons emitted by high-redshift quasars (Kronberg et al. 2008) suggests similar magnetic fields are present in foreground galaxies with redshifts z > 1. As Faraday rotation alone, however, determines neither the magnitude nor the redshift of the magnetic field, the strength of galactic magnetic fields at redshifts z > 0 remains uncertain.Here we report a measurement of a magnetic field of B ≈ 84 μG in a galaxy at z =0.692, using the same Zeeman-splitting technique that revealed an average value of B = 6 μG in the neutral interstellar gas of our Galaxy (Heiles et al. 2004). This is unexpected, as the leading theory of magnetic field generation, the mean-field dynamo model, predicts large-scale magnetic fields to be weaker in the past, rather than stronger (Parker 1970).The full text of this paper was published in Nature (Wolfe et al. 2008).

A Turbulent Heliosheath Driven by Rayleigh Taylor Instability

2021 ◽  
Author(s):  
Merav Opher ◽  
James Drake ◽  
Gary Zank ◽  
Gabor Toth ◽  
Erick Powell ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Large Scale ◽  
Neutral Atom ◽  
Solar Magnetic Field ◽  
Characteristic Time Scale ◽  
Rayleigh Taylor Instability ◽  
Scale Turbulence ◽  
Magnetohydrodynamic Simulations ◽  
Rt Instability

Abstract The heliosphere is the bubble formed by the solar wind as it interacts with the interstellar medium (ISM). Studies show that the solar magnetic field funnels the heliosheath solar wind (the shocked solar wind at the edge of the heliosphere) into two jet-like structures1-2. Magnetohydrodynamic simulations show that these heliospheric jets become unstable as they move down the heliotail1,3 and drive large-scale turbulence. However, the mechanism that produces of this turbulence had not been identified. Here we show that the driver of the turbulence is the Rayleigh-Taylor (RT) instability caused by the interaction of neutral H atoms streaming from the ISM with the ionized matter in the heliosheath (HS). The drag between the neutral and ionized matter acts as an effective gravity which causes a RT instability to develop along the axis of the HS magnetic field. A density gradient exists perpendicular to this axis due to the confinement of the solar wind by the solar magnetic field. The characteristic time scale of the instability depends on the neutral H density in the ISM and for typical values the growth rate is ~ 3 years. The instability destroys the coherence of the heliospheric jets and magnetic reconnection ensues, allowing ISM material to penetrate the heliospheric tail. Signatures of this instability should be observable in Energetic Neutral Atom (ENA) maps from future missions such as IMAP4. The turbulence driven by the instability is macroscopic and potentially has important implications for particle acceleration.

scholarly journals Sun-like Stars: magnetic fields, cycles and exoplanets

2015 ◽  
Vol 11 (A29A) ◽  
pp. 360-364
Author(s):  
Rim Fares
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Large Scale ◽  
Observational Constraints ◽  
The Sun ◽  
Field Generation ◽  
Large Scale Magnetic Field ◽  
Planetary Orbits ◽  
Activity Cycles ◽  
Magnetic Cycles

AbstractIn Sun-like stars, magnetic fields are generated in the outer convective layers. They shape the stellar environment, from the photosphere to planetary orbits. Studying the large-scale magnetic field of those stars enlightens our understanding of the field properties and gives us observational constraints for field generation dynamo models. It also sheds light on how “normal” the Sun is among Sun-like stars. In this contribution, I will review the field properties of Sun-like stars, focusing on solar twins and planet hosting stars. I will discuss the observed large-scale magnetic cycles, compare them to stellar activity cycles, and link that to what we know about the Sun. I will also discuss the effect of large-scale stellar fields on exoplanets, exoplanetary emissions (e.g. radio), and habitability.

scholarly journals Generation of strong magnetic fields with a laser-driven coil

2018 ◽  
Vol 6 ◽  
Author(s):  
Zhe Zhang ◽  
Baojun Zhu ◽  
Yutong Li ◽  
Weiman Jiang ◽  
Dawei Yuan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Experimental Studies ◽  
Diagnostic Techniques ◽  
Magnetic Field Generation ◽  
Field Generation ◽  
Research Fields ◽  
Laser Facility ◽  
Spatio Temporal ◽  
The Magnetic Field

As a promising new way to generate a controllable strong magnetic field, laser-driven magnetic coils have attracted interest in many research fields. In 2013, a kilotesla level magnetic field was achieved at the Gekko XII laser facility with a capacitor–coil target. A similar approach has been adopted in a number of laboratories, with a variety of targets of different shapes. The peak strength of the magnetic field varies from a few tesla to kilotesla, with different spatio-temporal ranges. The differences are determined by the target geometry and the parameters of the incident laser. Here we present a review of the results of recent experimental studies of laser-driven magnetic field generation, as well as a discussion of the diagnostic techniques required for such rapidly changing magnetic fields. As an extension of the magnetic field generation, some applications are discussed.

scholarly journals Magneto-Rayleigh–Taylor instability in an elastic finite-width medium overlying an ideal fluid

2019 ◽  
Vol 867 ◽  
pp. 1012-1042 ◽  
Author(s):  
S. A. Piriz ◽  
A. R. Piriz ◽  
N. A. Tahir
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Ideal Fluid ◽  
Taylor Instability ◽  
Finite Width ◽  
Unexpected Result ◽  
Magnetic Field Effects ◽  
Linear Elastic ◽  
Rayleigh Taylor Instability ◽  
The Stability

We present the linear theory of two-dimensional incompressible magneto-Rayleigh–Taylor instability in a system composed of a linear elastic (Hookean) layer above a lighter semi-infinite ideal fluid with magnetic fields present, above and below the layer. As expected, magnetic field effects and elasticity effects together enhance the stability of thick layers. However, the situation becomes more complicated for relatively thin slabs, and a number of new and unexpected phenomena are observed. In particular, when the magnetic field beneath the layer dominates, its effects compete with effects due to elasticity, and counteract the stabilising effects of the elasticity. As a consequence, the layer can become more unstable than when only one of these stabilising mechanisms is acting. This somewhat unexpected result is explained by the different physical mechanisms for which elasticity and magnetic fields stabilise the system. Implications for experiments on magnetically driven accelerated plates and implosions are discussed. Moreover, the relevance for triggering of crust-quakes in strongly magnetised neutron stars is also pointed out.

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