Plasma diagnostics in Hg free short arc lamps for automotive lighting

Kettlitz, M.; Krylova, O.; Wendt, Martin; Schneidenbach, H.; Gunther, K.

doi:10.1109/ias.2005.1518661

Cited by 3 publications

(4 citation statements)

References 5 publications

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“…The observed temperature profiles are similar to those distributions, Dakin et al [11] predicted by model calculations and Kettlitz and Pursch 2001 [4] which is significantly higher than our value of about 300 µm. Considering the very steep gradient of the plasma temperature towards the electrodes, it was not surprising, those their top values of nearly 7300 K also exceed our T p data, significantly (see figure 3 in [4]). However, in contrast to our findings, and the experimental results published by Work [10], they could not detect the marked temperature variation in dependence of the electrode polarity.…”

Section: Horizontal Operation-influence Of Convection Is Neglectedsupporting

confidence: 91%

“…To achieve these objectives, former progress has been made in a more empirical manner. Recent advances in experiment [1][2][3][4][5] and modelling [5][6][7] are so promising that a new quality in design of high-intensity discharge (HID) lamps should be achievable. Despite these advances, further efforts are necessary to improve the basic understanding of the manifold of physical and chemical processes especially in metal-halide (MH) lamps.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the connection between plasma temperature and electrode temperature in metal-halide lamps

Fromm

Lieder

Gleixner

2002

J. Phys. D: Appl. Phys.

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Spatial profiles of electrode temperatures and plasma temperatures have been measured on `real' HID lamps filled with a commercial metal-halide compound. The absolute accuracy of pyrometric determination of electrode tip temperatures was ±30 K, while the determination of plasma core temperatures, using a modified Bartels method, has an accuracy of ±100 K. We could deduce a close correlation between the plasma temperature in front of an electrode Tp and its tip temperature Tt due to the influence of the cataphoresis. If Tp is reduced at the cathode the Tt value has also lowered, whereas Tp at the anode is raised together with its Tt data. This correlation disappears at ballast frequencies above 100 Hz, whereas the cataphoresis influence on Tp continues up to 500 Hz. Based on the latter limit, a rough estimation of the cataphoresis velocity delivers 700 cm s-1. As a tentative interpretation, we suggest that the connection between Tp and Tt is caused by an increase of the ion part of the total current at the cathode due to Na accumulation before it. Thus, the cathode has to emit fewer electrons and works at a lower temperature. Further results are the temporal behaviour of Tt depends on the ballast type. For vertical operation the strong influence of convection on Tt has also to be taken into account. Above 100 Hz, where only convection plays a role, the upper electrode Tt exceeds the Tt value of the lower electrode by nearly 400 K. This discrepancy one may explain, tentatively, by convection heating of the upper electrode and convection cooling of the lower one.

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Section: Horizontal Operation-influence Of Convection Is Neglectedsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Investigation of the connection between plasma temperature and electrode temperature in metal-halide lamps

Fromm

Lieder

Gleixner

2002

J. Phys. D: Appl. Phys.

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“…For Stark broadening C 4 = 1.560 × 10 −22 and 1.557 × 10 −22 m 4 s −1 follow from Stark linewidths given by Griem [18] and applying equation (8). Van der Waals broadening constants of C 6 = 6.127 × 10 −43 m 6 s −1 and 7.629 × 10 −43 m 6 s −1 for the Na 589.0 nm and the 589.6 nm lines, respectively, follow from widths reported by Nieuwesteeg et al [19] and applying equation (9). Earlier values were reported by Allard and Kielkopf [20] and Jongerius [21].…”

Section: Theorysupporting

confidence: 70%

“…Besides an optimization of the lamp design with respect to the materials, it was necessary to perform plasma diagnostics to understand the processes inside the lamp and to find optimized operation conditions [9,10]. This paper concentrates on the plasma diagnostics in mercury-free discharge lamps.…”

Section: Introductionmentioning

confidence: 99%

Plasma diagnostics in Hg-free short-arc lamps for automotive lighting

Kettlitz¹,

Wendt²,

Schneidenbach³

et al. 2007

J. Phys. D: Appl. Phys.

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In the context of developing a mercury-free lamp for automotive lighting an optimization of lamp design and plasma radiation was performed. In contrast to existing quartz lamps, a new lamp design was chosen consisting of a sapphire capillary combined with ceramic parts and pure tungsten electrodes. The lamps consist of metal halides and between 1 and 20 bar of xenon. They were operated with an electronic ballast at input powers between 20 and 40 W. Besides an optimization of the tube materials, thermography and plasma diagnostics were performed to understand the processes inside the lamp and to find optimal operation conditions. In addition to experimental diagnostics, a simulation of self-reversed sodium spectral lines was performed to verify plasma parameters, particularly the xenon pressure which could not be determined from the experiment. Additionally, tendencies of the influence of single components could be estimated by modelling.

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