Ignition Concepts for High Frequency Operated HID Lamps

Ac breakdown in near-atmospheric pressure noble gases: I. Experiment

“…Later observations of the lowering of the threshold voltage when switching to highfrequency AC voltage [1][2][3][4][5][6][7], and also as the frequency was increased, brought on again the same theories and possible explanations afore proposed by Meek and Craggs [8]. For high frequencies it was argued that the electron drift losses were lowered, which caused a more favourable ratio between electron production and loss [2,4].…”

“…We have shown results that call attention to the influence of the driving frequency, the gas type and the two ignition helpers -UV irradiation and radioactive material. In previous work concerning breakdown in the frequency ranging from 100 kHz to about 50 MHz [1][2][3][4][5][6][7][8], there were two ideas about which processes are important in discharge development and why AC breakdown is possible at lower voltages than for the pulsed breakdown. The first explanation concerns limited drift of electrons within the electrode gap between the electrodes at high enough frequencies, limiting drift losses and effectively increasing the ratio of electron source and sink in a single voltage cycle.…”

“…Also, both volume and surface AC discharges that occur in partial vacuum are of particular interest for aerospace insulating technology and power devices operating in space [5]. The lighting industry focuses on AC discharges in near-atmospheric pressure noble gasses with an admixture of mercury when trying to achieve two important goals: one, to design ignition concepts for high-frequency operated lamps [6], and two, to lower the ignition voltage of lamps [7].…”

Ac breakdown in near-atmospheric pressure noble gases: II. Simulations

“…On the other hand, AC discharges found their use in the science of material processing, where the glow discharges created in atmospheric pressure possess the uniformity that is not present in filamentary discharges obtained in pulsed mode [3][4][5]. Also, some research on ACdriven discharges has been done for the lighting industry when trying to design ignition concepts for high-frequency operated lamps [6] or lower their ignition voltage [7].…”

Transition between breakdown regimes in a temperature-dependent mixture of argon and mercury using 100 kHz excitation

“…6 Applied in material processing, [7][8][9] high-frequency induced glow discharges created in atmospheric pressure possess the sought-for uniformity that is not present in filamentary discharges obtained in pulsed mode. The temperature, gas mixture, and the driving frequency are factors that influence the behaviour of plasma-driven lamps, 10 they affect their ignition voltage, 11 and they are important in understanding the breakdown process. 12,13 This study examines the electrical breakdown of a gaseous mixture at elevated pressures and temperatures and the associated transitions between breakdown regimes.…”