Triggering and guiding high-voltage large-scale leader discharges with sub-joule ultrashort laser pulses

Abstract

The triggering and guiding of leader discharges using a plasma channel created by a sub-joule ultrashort laser pulse have been studied in a megavolt large-scale electrode configuration ͑3-7 m rod-plane air gap͒. By focusing the laser close to the positive rod electrode it has been possible, with a 400 mJ pulse, to trigger and guide leaders over distances of 3 m, to lower the leader inception voltage by 50%, and to increase the leader velocity by a factor of 10. The dynamics of the breakdown discharges with and without the laser pulse have been analyzed by means of a streak camera and of electric field and current probes. Numerical simulations have successfully reproduced many of the experimental results obtained with and without the presence of the laser plasma channel.

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

“…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 strong electric fields at the two sharp extremities of the filament would then induce local CDs linking the filament with the two electrodes, as shown in Figure 3(d). Such CDs of the filament zone would be the precursor to induce a full discharge between two electrodes set at a high voltage difference [19][20][21][22][23][32][33][34][35][36] .…”

“…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] .…”

“…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.…”