Fig. 4
From: Effects of applied magnetic fields on the performance of magnetoplasmadynamic thrusters
Normalized ion energy distribution functions (IEDFs) measured using a retarding potential analyzer (RPA) for the electromagnet configuration at various argon flow rates. Peak ion energy increased with both discharge current and coil current, and was highest at the lowest flow rate (500 sccm). At a coil current of 10 A, the peak ion energy ranged between 21 eV and 35 eV. At the coil current of 40 A, the peak ion energy reaches 63 eV at the flow rate of 500 sccm, which is 66% higher than that observed at the flow rate of 1000 sccm (38 eV). This result indicates that a higher potential difference at lower flow rates leads to stronger ion acceleration.
