Characterization of E- to H-mode transition in inductively coupled argon-hydrogen plasma

Kurzfassung

Hydrogen-containing plasma is a promising alternative for CO_2 emission-free iron ore reduction [1]. In many applications, operation of inductively coupled plasma in the H-mode is favorable for higher process rates [2]. A low-temperature inductively coupled argon- hydrogen plasma is characterized at the transition from E- to H-mode to determine plasma parameters for iron ore reduction processes. A modified Gaseous Electronics Conference reference cell with a radio-frequency antenna powered at 13.56 Hz serves as plasma reactor [3]. Operating pressures are in the range of 5 Pa to 50 Pa in an argon- hydrogen (9:1) gas mixture. The plasma is monitored during the mode transition by an inline voltage, current and phase measurement, optical emission spectroscopy and microwave interferometry. Consequently, transition threshold powers, plasma densities, hydrogen dissociation degrees and electron temperatures are evaluated. [1] Sabat, K.; Murphy, A. doi: 10.1007/s11663-017-0957-1 (2017) [2] Ahr, P. et al. doi: 10.1088/0963-0252/24/4/044006 (2015) [3] Miller, P. et al. doi: 10.6028/jres.100.032 (1995)