Zobrazeno 1 - 10
of 129
pro vyhledávání: '"Field, George B."'
Autor:
Field, George B., Carroll, Sean M.
We argue that if axions are the dark matter, their coupling to electromagnetism results in exponential growth of a helical magnetic field when the axion field first rolls down its potential. After an inverse cascade, the relevant length scales to day
Externí odkaz:
http://arxiv.org/abs/2307.05425
The kinetic energy of supersonic turbulence within interstellar clouds is subject to cooling by dissipation in shocks and subsequent line radiation. The clouds are therefore susceptible to a condensation process controlled by the specific entropy. In
Externí odkaz:
http://arxiv.org/abs/2001.02678
Autor:
Blackman, Eric G., Field, George B.
The magnetic Reynolds number R_M, is defined as the product of a characteristic scale and associated flow speed divided by the microphysical magnetic diffusivity. For laminar flows, R_M also approximates the ratio of advective to dissipative terms in
Externí odkaz:
http://arxiv.org/abs/0801.0112
We present a model in which the supersonic motions observed in molecular clouds are driven by gravitational energy released as large structures fragment into smaller ones. The fragmentation process begins in large molecular clouds, and continues down
Externí odkaz:
http://arxiv.org/abs/astro-ph/0601574
Autor:
Blackman, Eric G., Field, George B.
Considering a plasma with an initially weak large scale field subject to nonhelical turbulent stirring, Zeldovich (1957), for two-dimensions, followed by others for three dimensions, and Zeldovich et al. (1983) have presented formulae of the form $
Externí odkaz:
http://arxiv.org/abs/astro-ph/0504507
Autor:
Blackman, Eric G., Field, George B.
Publikováno v:
Phys.Plasmas 11 (2004) 3264
A non-linear, time-dependent, magnetically driven dynamo theory which shows how magnetically dominated configurations can relax to become helical on the largest scale available is presented. Coupled time-dependent differential equations for large sca
Externí odkaz:
http://arxiv.org/abs/astro-ph/0303354
Autor:
Blackman, Eric G., Field, George B.
Publikováno v:
Phys.Fluids 15 (2003) L73
We develop a simple mean field approach to the transport of a passive scalar for which the fundamental equation is a second order differential equation in the transported quantity, not a first order equation. Triple correlations are included, as they
Externí odkaz:
http://arxiv.org/abs/astro-ph/0302013
Autor:
Blackman, Eric G., Field, George B.
Publikováno v:
Phys. Rev. Lett. 89 265007 (2002)
We develop a new nonlinear mean field dynamo theory that couples field growth to the time evolution of the magnetic helicity and the turbulent electromotive force, $\emfb$. We show that the difference between kinetic and current helicities emerges na
Externí odkaz:
http://arxiv.org/abs/astro-ph/0207435
Autor:
Field, George B., Blackman, Eric G.
Publikováno v:
Astrophys.J. 572 (2002) 685
We present a two-scale approximation for the dynamics of a nonlinear $\alpha^2$ dynamo. Solutions of the resulting nonlinear equations agree with the numerical simulations of Brandenburg (2001), and show that $\alpha$ is quenched by the buildup of ma
Externí odkaz:
http://arxiv.org/abs/astro-ph/0111470