Three-dimensional modeling of magnetic field inflation by plasma injection

Three-dimensional simulations of the expansion of plasma injected into a dipole magnetic field are conducted with a kinetic ion, massless fluid electron (hybrid) electromagnetic code. Two different types of magnetic field expansions are considered, i.e., high-density plasma is injected into a dipole magnetic field with or without a background magnetic field. It is found that the existence of the background magnetic field not only changes the particle distribution, but also significantly changes the extent of magnetic field inflation. The effects of plasma injection velocity on magnetic field inflation are also studied in this paper. It is shown that the higher the injection velocity, the larger the size of the inflated magnetic bubble. For the lower injection velocity, the gyroradii of the injected particles to the dipole field scale length are small so that the particles are trapped in the dipole field.