Triggering, guiding and deviation of long air spark discharges with femtosecond laser filament

Abstract

In the perspective of the laser lightning rod, the ability of femtosecond filaments to trigger and to guide large scale discharges has been studied for several years. The present paper reports recent experimental results showing for the first time that filaments are able not only to trigger and guide but also to divert an electric discharge from its normal path. Laser filaments are also able to divert the spark without contact between laser and electrodes at large distance from the laser. A comparison between negative and positive discharge polarities also reveals important discrepancies in the guiding mechanism

Prolongation of the lifetime of guided discharges triggered in atmospheric air by femtosecond laser filaments up to 130 μs

“…The weakly ionized plasma column and subsequent low density channel generated by laser filaments allow the precise triggering and guiding of electric discharges between two electrodes with a significant reduction of the breakdown voltage [7][8][9] . This effect is potentially useful for the development of laser lightning rod 4,[10][11] , high-voltage, high-current switches 12 , or virtual plasma antennas [13][14] .…”

“…In the last decade femtosecond laser filaments has proved to be a powerful tool to trigger and guide electric discharges in atmospheric air 1 with gap length of a few meters [2][3][4][5][6] . The weakly ionized plasma column and subsequent low density channel generated by laser filaments allow the precise triggering and guiding of electric discharges between two electrodes with a significant reduction of the breakdown voltage [7][8][9] .…”

“…Injection of electric current through guided discharges appears to be a more promising way. The duration of the guided discharge mostly depends on the high voltage (HV) source, with a typical duration on the order of 100 ns [2][3][4]14 . In several publications, a Marx generator was used as the HV source to produce meter scale guided discharges.…”

Spectroscopic analysis of high electric field enhanced ionization in laser filaments in air for corona guiding

“…The possibility of using a laser filament to couple the external electromagnetic fields and initiate the high-voltage discharge [32] has been successfully demonstrated [33] . Although there are many experimental contributions on filament-guided discharges [19][20][21][22][23][32][33][34][35][36] , investigations on how a laser filament guides the external high-voltage corona discharge (CD) had not been fully explored yet until recently, when we reported on a direct observation of laser-filament-guided CDs [37] . When a laser filament was generated at ∼1 mm from the tip of a copper electrode, as shown in Figure 1(a), a high DC voltage of 50 kV could be guided along the laser filament, forming blue CDs on both ends of the filament.…”

“…During femtosecond laser FIL in air, many nonlinear effects occur simultaneously, such as intensity clamping, molecular alignment, harmonic generation, self-phase modulation and so on [3][4][5] . These complex and interesting nonlinear phenomena accompanying femtosecond laser FIL lead to promising applications in different fields, such as remote sensing [6,7] , few-cycle pulse compression [8] , atmospheric condensation and precipitation [9][10][11] , secondary light source generation ranging from air lasing to terahertz emission [12][13][14][15][16][17][18] , and triggering and guiding high-voltage discharge with possible applications in lightning control [19][20][21][22][23][24] .…”