Results are presented of a first study of collisionless magnetic reconnection starting from a recently found exact nonlinear force-free Vlasov–Maxwell equilibrium. The initial state has a Harris sheet magnetic field profile in one direction and a non-uniform guide field in a second direction, resulting in a spatially constant magnetic field strength as well as a constant initial plasma density and plasma pressure. It is found that the reconnection process initially resembles guide field reconnection, but that a gradual transition to anti-parallel reconnection happens as the system evolves. The time evolution of a number of plasma parameters is investigated, and the results are compared with simulations starting from a Harris sheet equilibrium and a Harris sheet plus constant guide field equilibrium.
Wilson, F., Neukirch, T., Hesse, M., Harrison, M. G., & Stark, C. R. (2016). Particle-in-cell simulations of collisionless magnetic reconnection with a non-uniform guide field. Physics of Plasma, 23(3), . https://doi.org/10.1063/1.4942939