Gravitational wave produ tion: A strong onstraint on primordial magneti elds

Gravitational wave production A strong constraint on primordial magnetic fields CAPRINI, Chiara, DURRER, Ruth We compute the gravity waves induced by anisotropic stresses of stochastic primordial magnetic fields. The nucleosynthesis bound on gravity waves is then used to derive a limit on the magnetic field amplitude as function of the spectral index. The obtained limits are extraordinarily strong: If the primordial magnetic field is produced by a causal process, leading to a spectral index CAPRINI, Chiara, DURRER, Ruth. Gravitational wave production A strong constraint on primordial magnetic fields. Physical Review. D, 2002, vol. 65, no. 023517 DOI: 10.1103/PhysRevD.65.023517 arxiv: astro-ph/010624