Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-08-01
Astronomy and Astrophysics
Astrophysics
revised version, 10 pages, including 3 figs., in press, Physics of Plasmas
Scientific paper
10.1063/1.2409606
The linear growth rate and saturation level of magnetic fields for Weibel instabilities driven by ion temperature anisotropy, defined as $\alpha=(T_\perp/T_\parallel)-1$ where $T_\perp$ and $T_\parallel$ are ion temperatures perpendicular and parallel to the wave vector, are derived in the small $\alpha$-limit. It is shown that the ratio of the saturated magnetic energy to the initial ion energy scales as the fourth power of the electron to ion mass ratio, $m/M$, for an initially unmagnetized plasma with $\alpha\leq M/m$. Particle-in-cell simulations confirm the mass scaling and also show that the electron energy gain is of the same order of magnitude as the magnetic field energy. This implies that the Weibel instabilities cannot provide a faster-than-Coulomb collisionless mechanism to equilibrate ion-electron plasmas with ions initially much hotter than electrons, a key component in low-luminosity astrophysical accretion flows. The results here also show that the large $\alpha$-limit formulae used in the study of magnetic field generation in collisionless shocks are only valid if $\alpha\geq M/m$.
Blackman Eric G.
Fong Wen-fai
Ren Chuang
No associations
LandOfFree
Understanding the saturation of proton-driven Weibel instabilities and implications for astrophysics does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Understanding the saturation of proton-driven Weibel instabilities and implications for astrophysics, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Understanding the saturation of proton-driven Weibel instabilities and implications for astrophysics will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-265211