Kink instability as a particle acceleration mechanism in X-ray binaries and the connection to the outburst cycle

Abstract: We consider whether the kink instability can explain particle acceleration in hard state 'compact' X-ray binary jets. We apply a 1D model to assess the expected growth rate of the instability for a variety of jet models, then scale results from simulations to estimate a dissipation rate for the magnetic energy in the jet. We then consider the effects of radiative cooling on the system. We find that hard state 'compact' X-ray binary jets are likely to be unstable to the kink instability within their acceleration zones across a plausible parameter space. We further find that depending on the parameters of the model, the jets may radiate over a variety of length scales ranging from length scales attributable to a 'failed' jet scenario, to those in keeping with resolved radio observations of 'compact' jets. We discuss the expected evolution of this model through the outburst cycle.