A Turbulent Model of Gamma-Ray Burst Variability

A popular paradigm to explain the rapid temporal variability observed in gamma-ray burst (GRB) light curves is the internal shock model. We propose an alternative model in which the radiating fluid in the GRB shell is relativistically turbulent with a typical eddy Lorentz factor γ t. In this model, all pulses in the gamma-ray light curve are produced at roughly the same distance R from the centre of the explosion. The burst duration is ∼R/c 2, where is the bulk Lorentz factor of the expanding shell, and the duration of individual pulses in the light curve is ∼R/c 2γ 2 t . The model naturally produces highly variable light curves with ∼γ t individual pulses. Even though the model assumes highly inhomogeneous conditions, nevertheless the efficiency for converting jet energy to radiation is high.