An electron cyclotron resonance (ECR) plasma reactor developed at the European Spallation Source Bilbao has been operated in pulsed mode at 50 Hz to study the breakdown-process dynamics by time-resolved diagnostics. Injected power, reflected power, electrical-biased probe saturation current, and light emission were measured simultaneously for three different magnetic fields: under ECR, ECR, and asymmetric over ECR profiles. Gas pressure, power, and duty cycle have been used in a parametric study obtaining information about microwave (MW) coupling and plasma formation stages during the breakdown process. The study is relevant for designers that need to extract short beam pulses from a 2.45 ECR ion source for any application because the total breakdown time measured is defined as corresponding to reach the steady-state plasma parameters. A simple model of residual electron density evolution between pulses is proposed to describe the MW coupling as a function of incoming power and duty cycles.
Palabras Clave: Electron cyclotron resonance (ECR) plasma source, plasma breakdown, pulsed ECR ion source.
Índice de impacto JCR y cuartil WoS: 0.868 - Q4 (2012); 1.222 - Q4 (2020)
Referencia DOI: 10.1109/TPS.2012.2222933
Publicado en papel: Diciembre 2012.
Publicado on-line: Octubre 2012.
O.D. Cortázar, A. Megia-Macías, A. Vizcaíno-de-Julián. Experimental study of breakdown time in a pulsed 2.45-GHz ECR hydrogen plasma reactor. IEEE Transactions on Plasma Science. Vol. 44, nº. 12, pp. 3409 - 3419, Diciembre 2012. [Online: Octubre 2012]