The RAIJIN project aims at the development of high-power electric propulsion systems for application on allelectric satellite buses, future orbit transfer vehicles, and deep-space exploration missions. The concept of thruster with anode layer was chosen for this project, and a 2 kW-class UT-58 engineering model designed and tested in this study. A special focus is put on the feasibility of economical usage of argon as an alternative propellant. Thrust performance and discharge oscillations are evaluated. Experimental results show that an anode efficiency of up to 24% can be achieved with argon at small oscillation amplitude for a power input of 2 kW and an argon mass flow of 2.9 mg/s.