Generation of negative potential pulses in a massive negative ion plasma

Massive negative ions (C60−) are locally produced in a collisionless magnetized-plasma (Q-machine plasma) column for the purpose of investigating a new aspect of negative ion plasma. It is experimentally found that time-averaged plasma profiles along the magnetic field are uniquely modified around the production region of massive negative ions, and a transition from stationary to dynamical plasma states takes place depending on a production rate of massive negative ions. In the dynamical state, solitary pulses with negative potential are spontaneously excited. An electrostatic PIC simulation which is based on Q-machine configuration is simultaneously performed in order to clarify effects of the local production of massive negative ions on the plasma structure. It is worth noting that in case of high production rate solitary pulses are intermittently excited and play a role in the rapid ejection of massive negative ions from the system.