We have developed a 2½-dimensional open boundary particle simulation model and
have studied the current-driven electrostatic ion-cyclotron instability and related
d.c. potential difference. Fresh streaming electrons are injected smoothly from the
boundaries at each time step, avoiding unphysical accumulation of charged particles
in front of the boundaries. As a current-driven electrostatic ion cyclotron instability
grows, a d.c. potential difference along the magnetic field lines is created.