Numerical Simulations of Gravitational Waves from Early-Universe Turbulence

Understand

We perform direct numerical simulations of magnetohydrodynamic turbulence in the early universe and numerically compute the resulting stochastic background of gravitational waves and relic magnetic fields.

• These simulations do not make the simplifying assumptions of earlier analytic work.
• If the turbulence is assumed to have an energy-carrying scale that is about a hundredth of the Hubble radius at the time of generation, as expected in a first-order phase transition, the peak of gravitational wave power will be in the mHz frequency range for a signal produced at the electroweak scale.
• The efficiency of gravitational wave (GW) production varies significantly with how the turbulence is driven.