Summary:
Temporal evolution of microwave-plasma coupling, vacuum ultraviolet (VUV) light emission and plasma electron temperature and density is reported for a 2.45 GHz microwave hydrogen discharge pulsed at 50 Hz. Directional couplers, a VUV spectrometer and a Langmuir probe are used for the diagnostics of the plasma breakdown. A 5–10 µs transient peak of light emission exceeding the steady-state intensity by a factor of 3.3 is observed in coincidence with an abrupt drop in the microwave electric field. Observed light emission intensities combined with cross section data indicate that the electron temperature during the breakdown transient exceeds the steady-state value of 4–6 eV by a factor ⩾3, which is in good agreement with the Langmuir probe data. The estimated magnitude of the electron temperature transient corresponds well with the microwave-plasma coupling characteristics, indicating a drop of 30–40% in the electric field strength due to plasma damping.
JCR Impact Factor and WoS quartile: 3,056 - Q1 (2013); 3,300 - Q1 (2023)
DOI reference:
https://doi.org/10.1088/0963-0252/22/1/015026
Published on paper: February 2013.
Published on-line: February 2013.
Citation:
O.D. Cortázar, J. Komppula, O. Tarvainen, A. Megia-Macías, A. Vizcaíno-de-Julián, H. Koivisto, Experimental study of hydrogen plasma breakdown in a 2.45 GHz microwave discharge. Plasma Sources Science and Technology. Vol. 22, nº. 1, pp. 015026-1 - 015026-9, February 2013. [Online: February 2013]
