Characteristics of an E×B probe for extraction of H− ions from a magnetized sheet plasma source

An E×B probe is characterized by investigating its two parameters, namely extraction voltage (Vext) and lens voltage (Vlens). The effects of Vext and Vlens on the extracted H− ion current are examined. The investigation of Vext effects is done with a constant Vlens=0 V. The results show that the optimum value for negative ion extraction is Vext=190 V. With this optimum Vext, the Vlens parameter is examined. Findings show that the optimum Vlens is 0 V. Optimized parameters give the highest ion current and narrowest full width at half maximum. With these optimum settings, the E×B probe is used to study the variation of H− ions as a function of perpendicular distance (i.e., 1 cm to 4 cm) from the center of a magnetized sheet plasma with Bave=6.59 mT.