Simulations of the generation of partial nongyrotropy of newborn ions

The nongyrotropy of newborn ions in solar wind plasmas is studied by means of one-dimensional electromagnetic hybrid computer simulations of homogeneous plasmas. It is found that, contrary to the previous theory of nongyrotropy, the homogeneous injections of newborn ions can also produce the nongyrotropy of newborn ions (partial nongyrotropy). However, the inhomogeneous injections of newborn ions can make the ion nongyrotropy stronger. The newborn ion nongyrotropy is different within different perpendicular velocity range, and is strongest in the velocity range close to the injection velocity of newborn ions Vin.