DYNAMIC TRAPPING - NEUTRALIZATION OF POSITIVE SPACE-CHARGE IN A COLLISIONLESS MAGNETIZED PLASMA

It is shown by numerical simulations that in a collisionless plasma electron inertia leads to inefficient neutralization of positive space charge and allows large positive potentials (kTe/e) to be established and maintained on the time scale of ion motion. This is true even if the buildup of positive space charge is so slow that it corresponds to a small fraction of the random electron current of the surrounding plasma. A simple physical model clarifies the physics of the process and provides an analytical expression for the potential. © 1990 The American Physical Society.