Magnetic field generation in a jet-sheath plasma via the kinetic Kelvin-Helmholtz instability

Abstract

We have investigated generation of magnetic fields associated with velocity shear between an unmagnetized relativistic jet and an unmagnetized sheath plasma. We have examined the strong magnetic fields generated by kinetic shear (Kelvin-Helmholtz) instabilities. Compared to the previous studies using counter-streaming performed by Alves et al. (2012), the structure of KKHI of our jet-sheath configuration is slightly different even for the global evolution of the strong transverse magnetic field. In our simulations the major components of growing modes are the electric field $E_{\mathrm{z}}$ and the magnetic field $B_{\mathrm{y}}$. After the $B_{\mathrm{y}}$ component is excited, an induced electric field $E_{\mathrm{x}}$ becomes significant. However, other field components remain small. We find that the structure and growth rate of KKHI with mass ratios $m_{\mathrm{i}}/m_{\mathrm{e}}=1836$ and $m_{\mathrm{i}}/m_{\mathrm{e}}=20$ are similar. In our simulations saturation in the nonlinear stage is not as clear as in counter-streaming cases. The growth rate for a mildly-relativistic jet case (${\gamma }_{\mathrm{j}}=1.5$) is larger than for a relativistic jet case (${\gamma }_{\mathrm{j}}=15$).

6 pages, 6 figures, presented at Dynamical processes in space plasmas II, Isradinamic 2012, in press, ANGEO. arXiv admin note: text overlap with arXiv:1303.2569

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Cited by in corpus (13)

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• PIC methods in astrophysics: Simulations of relativistic jets and kinetic physics in astrophysical systems
• Evolution of Global Relativistic Jets: Collimations and Expansion with kKHI and the Weibel Instability
• Magnetic Field Generation in Core-Sheath Jets via the Kinetic Kelvin-Helmholtz Instability
• Transverse electron-scale instability in relativistic shear flows
• Relativistic Positron-Electron-Ion Shear Flows and Application to Gamma-Ray Bursts
• Relativistic Shear Flow Between Electron-Ion and Electron-Positron Plasmas and Astrophysical Applications
• Microscopic Processes in Global Relativistic Jets Containing Helical Magnetic Fields
• 3D PIC Simulations for Relativistic Jets with a Toroidal Magnetic Field
• Scaling of Relativistic Shear Flows with Bulk Lorentz Factor
• Particle-in-Cell simulation of two-dimensional electron velocity shear driven instability in relativistic domain
• Particle-in-cell Simulations of Global Relativistic Jets with Helical Magnetic Fields
• The effect of external magnetic field on electron scale Kelvin-Helmholtz instability