Cusp width and power flow study at a high power magnetic multipole ion source

Publisher Website
Google Scholar
Abstract
Power flow of the arc discharge on a high power magnetic multipole ion source is studied experimentally. Power flux distribution across line cusps is obtained using a probe made of a thermocouple. This confirms the fact that the full‐width leakage is almost twice the size of the ion Larmor radius. It is shown that the arc discharge had strong spatial distribution in the arc chamber. The absolute value of the power flux is determined by comparing the integrated values of the distribution with heat loading measured by the coolant temperature rise. The result revealed that a very high power flux of more than 500 W/cm2 is concentrated on the anode wall at the line cusp position for a moderate arc discharge condition. It is also shown that a large portion of arc power is carried by the neutral particles. The composition of the source plasma near the grid is estimated from the power flux on the extraction grid.