A large laser spark was produced in a homogeneous sulphur hexafluoride gas(pressures ranged from 10.7 to 101.3 kPa)by a focused high-power laser pulse(350 ps,125 J,1315.2 nm).Magnetic fields,electromagnetic pulses(EMP...A large laser spark was produced in a homogeneous sulphur hexafluoride gas(pressures ranged from 10.7 to 101.3 kPa)by a focused high-power laser pulse(350 ps,125 J,1315.2 nm).Magnetic fields,electromagnetic pulses(EMPs),optical emission spectra(OES)and chemical changes associated with the laser-induced dielectric breakdown(LIDB)in the SF6 gas were investigated.During the laser interaction,hot electrons escaping the plasma kernel produced EMPs and spontaneous magnetic fields,the frequency spectrum of which contains three bands around 1.15,2.1 and 3 GHz,while the EMP frequency band appeared around 1.1 GHz.The EMP emission from a laser spark was very weak in comparison to those generated at a solid target.Gas chromatography revealed the formation of only a limited number of products and a low degree of sulphur hexafluoride(SF_(6))conversion.OES diagnosed the LIDB plasma in the phase of its formation as well as during its recombination.展开更多
基金the Czech Ministry of Education,Youth and Sports(CMEYS)for the financial support of the project No.LM2023068(PALS RI)the Grant Agency of the Czech Republic(Project No.GM23-05027M)。
文摘A large laser spark was produced in a homogeneous sulphur hexafluoride gas(pressures ranged from 10.7 to 101.3 kPa)by a focused high-power laser pulse(350 ps,125 J,1315.2 nm).Magnetic fields,electromagnetic pulses(EMPs),optical emission spectra(OES)and chemical changes associated with the laser-induced dielectric breakdown(LIDB)in the SF6 gas were investigated.During the laser interaction,hot electrons escaping the plasma kernel produced EMPs and spontaneous magnetic fields,the frequency spectrum of which contains three bands around 1.15,2.1 and 3 GHz,while the EMP frequency band appeared around 1.1 GHz.The EMP emission from a laser spark was very weak in comparison to those generated at a solid target.Gas chromatography revealed the formation of only a limited number of products and a low degree of sulphur hexafluoride(SF_(6))conversion.OES diagnosed the LIDB plasma in the phase of its formation as well as during its recombination.
