Electron inertia and small-scale magnetic structures in a nonuniform collisionless plasma

In collisionless plasmas, electron inertia has a strong influence on the formation of magnetic islands, through magnetic field line reconnection, and on the dynamics of coherent nonlinear structures such as magnetic vortices. We present a physical model for the nonlinear dynamics of such magnetic structures in configurations with a strong magnetic field. This model includes diamagnetic velocities and ion gyro-radius and electron inertia effects and yields the so-called Reduced MagnetoHydroDynamic (RMHD) equations in the appropriate limit.