TIME-OF-FLIGHT ANALYSIS OF A PLASMA-JET FROM A SPARK PLUG IN VACUUM

The composition of a plasma jet and the velocity distribution of the different ions from an arc plasma source are investigated by a double time-of-flight method. The plasma source consists of a marine spark plug in coaxial configuration driven from a capacitor bank. The analysis of the plasma jet is performed by pulsed acceleration of plasma ions and measurement of their time of flight to a distant electron multiplier tube. Mainly oxygen and aluminum ions from the insulator are detected. The velocity of the highly ionized ions extends to 14 cm/mus. The lower ionized particles have lower initial velocities. The hydrogen ion content increases with increased time between shots.