TY - JOUR
T1 - Time resolved Thomson scattering measurements on a high pressure mercury lamp
AU - Vries, de, N.
AU - Zhu, Xiao-Yan
AU - Kieft, E.R.
AU - Mullen, van der, J.J.A.M.
PY - 2005
Y1 - 2005
N2 - Time resolved Thomson scattering (TS) measurements have been performed on an ac driven high pressure mercury lamp. For this high intensity discharge (HID) lamp, TS is coherent and a coherent fitting routine, including rotational Raman calibration, was used to determine ne and Te from the measured spectrum. The maximum electron density and electron temperature obtained in the centre of the discharge varied in a time period of 5 ms between 1 × 1021 m-3 <ne <5 × 1021 m-3 and 6500 K <Te <7100 K. In order to test the non-intrusive character of TS, we have derived a general expression for the heating of the electrons. By applying this to our mercury lamp and laser settings, we have confirmed the non-intrusiveness of our method. This is supported by the experimental findings. Furthermore, because the TS results were obtained directly, thus, without the local thermodynamic equilibrium (LTE) assumptions, they enabled us to follow the deviations from LTE as a function of time. Contrary to the generally made assumption that HID lamps are in LTE, we have found deviations from both the thermal and chemical equilibrium inside the high pressure mercury lamp at different phases of the applied current.
AB - Time resolved Thomson scattering (TS) measurements have been performed on an ac driven high pressure mercury lamp. For this high intensity discharge (HID) lamp, TS is coherent and a coherent fitting routine, including rotational Raman calibration, was used to determine ne and Te from the measured spectrum. The maximum electron density and electron temperature obtained in the centre of the discharge varied in a time period of 5 ms between 1 × 1021 m-3 <ne <5 × 1021 m-3 and 6500 K <Te <7100 K. In order to test the non-intrusive character of TS, we have derived a general expression for the heating of the electrons. By applying this to our mercury lamp and laser settings, we have confirmed the non-intrusiveness of our method. This is supported by the experimental findings. Furthermore, because the TS results were obtained directly, thus, without the local thermodynamic equilibrium (LTE) assumptions, they enabled us to follow the deviations from LTE as a function of time. Contrary to the generally made assumption that HID lamps are in LTE, we have found deviations from both the thermal and chemical equilibrium inside the high pressure mercury lamp at different phases of the applied current.
U2 - 10.1088/0022-3727/38/16/006
DO - 10.1088/0022-3727/38/16/006
M3 - Article
SN - 0022-3727
VL - 38
SP - 2778
EP - 2789
JO - Journal of Physics D: Applied Physics
JF - Journal of Physics D: Applied Physics
IS - 16
ER -