A method to generate kappa distributed random deviates for particle-in-cell simulations

The kappa distribution has been increasingly recognised as a versatile tool for the study and understanding of space plasmas. With its Maxwellian-like core and power-law tail it smoothly reproduces the velocity distribution of charged particles observed in space plasmas. Presented here is a simple and efficient method to generate pseudo-random deviates following the kappa distribution. This is presented within the context of modelling the initial particle velocity distributions in particle-in-cell (PIC) simulations. The Mathematical equivalence between the kappa distribution and the Student tt distribution is demonstrated. Using this equivalence, the well-known method of generating deviates for the Student tt distribution is tailored for the kappa distribution.