Measured spectral radiance of the red wing Hg 253.7 nm resonance line emitted at the discharge surface across a diameter at (a) the maximum current phase (5 ms) and (b) at the minimum current phase (0 ms) within the ac-cycle. The solid line represents the simulated spectral radiance.
Line-of-sight measurements of the radiance at the red self-reversal peak of the Hg 253.7 nm resonance line at the maximum (5 ms) and the minimum (0 ms) current phases vis-à-vis the lateral distance y of the line-of-sight to the arc axis.
Impact of the variation of the atomic temperature profile on the determination of the excitation temperature at the discharge center at the maximum (5 ms) and the minimum (0 ms) current phases. Calculations performed with a parabolic temperature profile with β = 2.5 (a), and with Tg (0) = 5460 K (b).
Radial distribution of the gas temperature (solid line) at (a) the maximum current phase (5 ms) and (b) the minimum (0 ms) current phase. The excitation temperature (dotted line) at the two moments is also shown.
Sensitivity of the method to the fitted parameters at 5 ms (solid lines). (a) p = 5.0 bars (red-dashed line), 5.4 bars (solid line), and 6.0 bars (blue-dashed-dotted line); (b) Tg (0) = 5160 K (red-dashed line), 5460 K (solid line), and 5760 K (blue-dashed-dotted line); (c) β = 2.0 (red-dashed line), 2.5 (solid line), and 3.0 (blue-dashed-dotted line).
Values of the parameters pressure, p, atomic temperature at the arc core, Tg (0), and exponent β in Eq. (7) obtained through the fitting process. For comparison the excitation temperature at the arc core, , as well as the electron temperature at the arc core Tel (0) which is previously obtained in Ref. 4, are also given in K.
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