Magnetohydrodynamics in the Early Universe and the Damping of Non-linear Alfven Waves Export

@article{Subramanian:1997gi, abstract = {The evolution and viscous damping of cosmic magnetic fields in the early universe, is analysed. Using the fact that the fluid, electromagnetic, and shear viscous energy-momentum tensors are all conformally invariant, the evolution is transformed from the expanding universe setting into that in flat spacetime. Particular attention is paid to the evolution of nonlinear Alfven modes. For a small enough magnetic field, which satisfies our observational constraints, these wave modes either oscillate negligibly or, when they do oscillate, become overdamped. Hence they do not suffer Silk damping on galactic and subgalactic scales. The smallest scale which survives damping depends on the field strength and is of order a dimensionless Alfven velocity times the usual baryon-photon Silk damping scale. After recombination, nonlinear effects can convert the Alfven mode into compressional, gravitationally unstable waves and seed cosmic structures if the cosmic magnetic field is sufficiently strong.}, archivePrefix = {arXiv}, author = {Subramanian, Kandaswamy and Barrow, John D.}, citeulike-article-id = {5032251}, citeulike-linkout-0 = {http://arxiv.org/abs/astro-ph/9712083}, citeulike-linkout-1 = {http://arxiv.org/pdf/astro-ph/9712083}, day = {5}, eprint = {astro-ph/9712083}, keywords = {alfven-waves, early-universe, magnetic-fields, nonlinear}, month = {Dec}, posted-at = {2009-07-01 13:47:38}, priority = {2}, title = {Magnetohydrodynamics in the Early Universe and the Damping of Non-linear Alfven Waves}, url = {http://arxiv.org/abs/astro-ph/9712083}, year = {1997} }

TY - JOUR ID - Subramanian:1997gi L3 - citeulike-article-id:5032251 N2 - The evolution and viscous damping of cosmic magnetic fields in the early universe, is analysed. Using the fact that the fluid, electromagnetic, and shear viscous energy-momentum tensors are all conformally invariant, the evolution is transformed from the expanding universe setting into that in flat spacetime. Particular attention is paid to the evolution of nonlinear Alfven modes. For a small enough magnetic field, which satisfies our observational constraints, these wave modes either oscillate negligibly or, when they do oscillate, become overdamped. Hence they do not suffer Silk damping on galactic and subgalactic scales. The smallest scale which survives damping depends on the field strength and is of order a dimensionless Alfven velocity times the usual baryon-photon Silk damping scale. After recombination, nonlinear effects can convert the Alfven mode into compressional, gravitationally unstable waves and seed cosmic structures if the cosmic magnetic field is sufficiently strong. TI - Magnetohydrodynamics in the Early Universe and the Damping of Non-linear Alfven Waves KW - alfven-waves KW - early-universe KW - magnetic-fields KW - nonlinear AU - Subramanian, Kandaswamy AU - Barrow, John PY - 1997/Dec/05/ UR - http://arxiv.org/abs/astro-ph/9712083 ER -