A Spontaneous Generation of the Magnetic Field and Suppression of the Heat Conduction in Cold Fronts

Abstract

We have determined the physical mechanism responsible for the plasma instabilities, which was first found by Ramani and Laval (1978), associated with anisotropic velocity distributions induced by the temperature gradient in which there are growing low frequency transverse magnetic waves, even in the absence of background magnetic fields. We have shown that the physical mechanism responsible for the growth of one of the modes is identical to the Weibel instability. The nonlinear saturation level of the instability is also provided by considering the wave-particle interactions. The non-linear evolutions of the magnetic fields after the saturation are speculated. The results are applied to the cold fronts which is one of the newly discovered structures in clusters of galaxies by the Chandra X-ray observatory. We predict the existence of the magnetic field of $\sim 10\mu$G tangential to the surface over the entire region of the cold front surface and that the heat conduction is significantly suppressed by the trapping of the electrons by the generated magnetic fields. The instability may provide a new possibility on the origin of cosmic magnetic field.

arXiv comment18 pages, 4 figures. Accepted for publication in the Astrophysical Journal

References in corpus (6)

• Chandra Observation of Abell 2142: Survival of Dense Subcluster Cores in a Merger
• A moving cold front in the intergalactic medium of A3667
• Chandra estimate of the magnetic field strength near the cold front in A3667
• Chandra constraints on the thermal conduction in the intracluster plasma of A2142
• A Cold Front in A3667: Hydrodynamics and Magnetic Field in the Intracluster Medium
• A possible route to spontaneous reduction of the heat conductivity by a temperature gradient driven instability in electron-ion plasmas

Cited by in corpus (21)

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• Hard X-ray Properties of the Merging Cluster Abell 3667 as Observed with Suzaku
• Generic estimates for magnetic fields generated during inflation including Dirac-Born-Infeld theories
• The Off-Axis Galaxy Cluster Merger Abell 115
• PIC simulations of the Thermal Anisotropy-Driven Weibel Instability: Field growth and phase space evolution upon saturation
• Magnetohydrodynamic Simulations of the Formation of Cold Fronts in Clusters of Galaxies including Heat Conduction
• The interrelation between the generation of large-scale electric fields and that of large-scale magnetic fields during inflation
• Cosmic Magnetism in Centimeter and Meter Wavelength Radio Astronomy
• Property of the spectrum of large-scale magnetic fields from inflation
• A Possible Origin of Magnetic Fields in Galaxies and Clusters: Strong Magnetic fields at z~10?
• On the X-Ray and Mass Distribution in the Merging Galaxy Cluster 1E 0657-56: Ram Pressure-Stripping in Substructures with an NFW Density Profile
• Fast magnetization in counterstreaming plasmas with temperature anisotropies
• Whistler instability in a semi-relativistic bi-Maxwellian plasma
• Magnetic field generation by the Weibel instability at temperature gradients in collisionless plasmas
• A Direct Method for Measuring Heat Conductivity in Intracluster Medium
• The Generation of Magnetic Fields and X-ray Observations
• Gravitational Lens Systems to probe Extragalactic Magnetic Fields
• Theory of the Jitter radiation in a magnetized plasma accompanying temperature gradient