Propagation of ionization waves during ignition of fluorescent lamps

Langer, Reinhard; Garner, R.C.; Hilscher, A.; Tidecks, R.; Horn, S.

doi:10.1088/0022-3727/41/14/144011

Cited by 22 publications

(31 citation statements)

References 15 publications

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“…Research was conducted in the universities of Eindhoven (Holland) and Augsburg (Germany) and in the laboratories of the leading CFL manufacturers: Phillips and OSRAM. The main results are presented in [35,36,[55][56][57][58][59][60], of which [56,57,59] are purely experimental, [35,36,58] are computational, and the results of both experiments and modeling are presented in [55,60]. The gases under study were the v w v w v w components of the mixtures used in the lamps: argon [35,56,57,60] or argon with mercury vapor [36,55,58,59]; in [59], there were also neon or krypton additives.…”

Section: Work Of the 1990s And Latermentioning

confidence: 99%

“…In [35,36,56,57], the polarity of the pulses was negative; in other works, pulses of both polarities were studied. The pulse duration in [55] was 10 ms and, in the rest of the papers, ~100 μs; the repetition period was 200 ms (400 ms in [55] and 10 s in [59]). With the exception of the latter, in other works, in the intervals between the main pulses, short resetting pulses with an amplitude obviously exceeding the breakdown voltage were applied to the electrodes.…”

Section: Work Of the 1990s And Latermentioning

confidence: 99%

“…It did not lead to a breakdown, but preionized the gas in the anode region and thereby eliminated the statistical delay of the breakdown. With the exception of [59], the discharge tube was surrounded with an electrostatic shield: a grounded metal pipe with a diameter of about 5 cm (3.5 cm in [55]). The purpose of the shield was to eliminate electrical interactions between the discharge and the remaining elements of the equipment, and, in the modeling, impose the boundary conditions for the IW.…”

Section: Work Of the 1990s And Latermentioning

confidence: 99%

“…As a rule, two ionization waves were observed: the first (forward) and return. However, the authors of [59] report about only one wave and the authors of [55] about three.…”

Section: Work Of the 1990s And Latermentioning

confidence: 99%

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Electric Breakdown in Long Discharge Tubes at Low Pressure (Review)

Ionikh

2020

Plasma Phys. Rep.

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The review is devoted to studies of the processes and mechanisms of ignition of a glow discharge in tubes whose length significantly exceeds their diameter (long discharge tubes) at low pressures (~10 Torr and lower) and moderate voltage rise rates (~1 kV/μs and lower). The electric field in such tubes before a breakdown is substantially nonuniform. Therefore, a breakdown occurs after an ionization wave (or waves) passes through the discharge gap at a speed of ~105–107 cm/s. This makes the characteristics of the breakdown in long tubes significantly different from the breakdown between large and closely spaced electrodes, where the electric field is uniform before the breakdown and where the Townsend or, under strong overvoltage, streamer mechanism is realized. On the other hand, the nature of these processes is very different from those occurring in nanosecond discharges, which arise at voltages with a steepness of ~1 kV/ns and higher and are associated with high-speed (~109 cm/s) ionization waves. The review is based on the materials of experimental and computational works published from 1938 to 2020. Breakdown processes, optical and electrical characteristics of the discharge gap during breakdown, and the influence of the external circuit parameters and external actions (shielding and illumination by external sources of visible radiation) are analyzed.

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Section: Work Of the 1990s And Latermentioning

confidence: 99%

Section: Work Of the 1990s And Latermentioning

confidence: 99%

Section: Work Of the 1990s And Latermentioning

confidence: 99%

“…As a rule, two ionization waves were observed: the first (forward) and return. However, the authors of [59] report about only one wave and the authors of [55] about three.…”

Section: Work Of the 1990s And Latermentioning

confidence: 99%

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Electric Breakdown in Long Discharge Tubes at Low Pressure (Review)

Ionikh

2020

Plasma Phys. Rep.

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“…The expression of the wave front velocity as a function of n e0 is thus obtained by combining (20) with (30), giving:…”

Section: Modelling Of the Pre-breakdown Wavementioning

confidence: 99%

Optical and electrostatic potential investigations of electrical breakdown phenomena in a low-pressure gas discharge lamp

Gendre¹,

Haverlag²,

Kroesen³

2010

J. Phys. D: Appl. Phys.

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The ignition phase is a critical stage in the operation of gas discharge lamps where the neutral gas enclosed between the electrodes undergoes a transformation from the dielectric state to a conducting phase, eventually enabling the production of light. The phenomena occurring during this phase transition are not fully understood and the related experimental studies are often limited to local optical measurements in environments prone to influencing these transient phenomena. In this work unipolar ignition phenomena at sub-kilovolt levels are investigated in a 3 Torr argon discharge tube. The lamp is placed in a highly controlled environment so as to prevent any bias on the measurements. A fast intensified CCD camera and a specially-designed novel electrostatic probe are used simultaneously so as to provide with a broad array of measured and computed parameters which are displayed in space-time diagrams for cross comparisons. Experiments show that three distinct phases exist during successful ignitions: Upon the application of voltage a first ionization wave starts from the active electrode and propagates in the neutral gas toward the opposite electrode. A local front of high axial E field strength is associated with this process and causes a local ionisation to occur, leading to the electrostatic charging of the lamp. Next, a second wave propagates from the ground electrode back toward the active electrode with a higher velocity, and in this process leads to a partial discharging of the lamp. This return stroke draws a homogeneous plasma column which eventually bridges both electrodes at the end of the wave propagation. At this point both electrode sheaths are formed and the common features of a glow discharge are observed. The third phase is an increase of the light intensity of the plasma column until the lamp reaches a steady state operation. Failed ignitions present only the first phase where the first wave starts its propagation but extinguishes in the lamp, leading to a charge memory effect. It is found that the full propagation of this first wave is a requirement for a successful lamp ignition. Differences in the properties of the waves were observed depending on the voltage polarity, and it was estimated that a photoelectric effect at the wall is the most likely source of electron for the ionisation wave of positive polarity. Finally a simple model of the first ionization wave is developed and used to analyse the fundamental differences between processes occurring at negative and at positive polarity. From this study three conditions are developed for the successful unipolar ignition of lamps and the relations between them are derived.

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