/spl delta/f simulation of tearing mode instability

Summary form only given. The evolution of the collisionless and collisional tearing mode is studied using a three-dimensional particle-in-cell simulation model that uses the /spl delta/f-method with the split-weight scheme to enhance the time step, and a novel algorithm to accurately solve the Ampere´s equation for experimentally relevant /spl beta/ values, /spl beta/ m/sub i//m/sub e//spl Gt/1. We use the model of drift-kinetic electrons and gyrokinetic/adiabatic ions. Linear simulation results are benchmarked with eigenmode analysis for the case of fixed ions, as can be shown that in small box simulations the ions response can be neglected. The nonlinear dynamics of magnetic islands are studied and the results are compared with previous theoretical studies. For large box simulations we have found instabilities like drift kink mode for which ions motion is more important compared to tearing modes. A collision operator is included in the electron drift kinetic equation to study the simulation in the semi-collisional and collisional regimes.