Multiple breakdown in helium generated by hybrid 10 ?m Co2 laser pulses

Kopiczynski, T.; Bogdan, M.; Kälin, A. W.; Schötzau, H. J.; Kneubühl, Fritz Kurt

doi:10.1007/bf00325520

Cited by 8 publications

(3 citation statements)

References 12 publications

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“…In our experiments, a minimum in the threshold power density versus pressure curve ( figure 3) is observed. The electron cascade process can also starts with an initial number of electrons in the focal volume that are produced by natural ionization due to cosmic radiation [49]. In air at atmospheric pressure, the natural electron density is ∼10 3 cm −3 .…”

Section: Laser-induced Breakdown Mechanism In Nitrogenmentioning

confidence: 99%

Optical emission studies of nitrogen plasma generated by IR CO₂laser pulses

Camacho

Poyato

Díaz

et al. 2007

J. Phys. B: At. Mol. Opt. Phys.

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Large-scale plasma produced in nitrogen gas at room temperature and pressures ranging from 4 × 10 3 to 1.2 × 10 5 Pa by high-power laserinduced dielectric breakdown (LIDB) has been investigated. Time-integrated optical nitrogen gas spectra excited from a CO 2 laser have been measured and analysed. The spectrum of the generated plasma is dominated by the emission of strong N + and N and very weak N 2+ atomic lines and molecular features of N (B-X) systems are very weak as compared with the chemiluminescence spectrum of nitrogen formed in a glow discharge. An excitation temperature T exc = 21 000 ± 1300 K was calculated by means of the relative intensity of ionized nitrogen atomic lines assuming local thermodynamic equilibrium. Optical breakdown threshold intensities in N 2 at 9.621 µm have been determined. The physical processes leading to the LIDB of nitrogen in the power density range 0.4 < J < 4.5 GW cm −2 have been analysed. From our experimental observations we can suggest that, although the first electrons must appear via multiphoton ionization or natural ionization, electron cascade is the main mechanism responsible for the LIDB in nitrogen.

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Section: Laser-induced Breakdown Mechanism In Nitrogenmentioning

confidence: 99%

Optical emission studies of nitrogen plasma generated by IR CO₂laser pulses

Camacho

Poyato

Díaz

et al. 2007

J. Phys. B: At. Mol. Opt. Phys.

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“…These free or quasifree electrons can be produced by the effect of cosmic ray ionization (natural ionization), by MPI, or a breakdown induced in some gas impurity. The natural electron density is ≈10 3 cm −3 [22].…”

Section: Optical Breakdown Threshold Intensities For Heliummentioning

confidence: 99%

Time-resolved optical emission spectroscopic measurements of He plasma induced by a high-power CO2 pulsed laser

Camacho

Díaz

Santos

et al. 2011

Spectrochimica Acta Part B: Atomic Spectroscopy

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“…Firstly, we calculate the continuous microwave propagation in argon with ω = 1.7593 × 10 10 s −1 , n e (0, z) = 1 × 10 9 m −3 , [26] E rms (t, 0) = 2 × 10 3 V/cm, p = 10 torr, and the propagation length z d = 60 mm. In the numerical calculation of the theoretical model, equations (3), (6), and (7) are taken.…”

Section: Continuous Microwave Attenuationmentioning

confidence: 99%

Microwave propagation with the gas breakdown

Liu¹,

Liu²,

Meng³

2014

Chinese Phys. B

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By combining the microwave propagation theory and the gas breakdown theory, the microwave propagation with the gas breakdown is analyzed theoretically. Particle-in-cell/Monte Carlo collision (PIC/MCC) simulations are carried out to verify the theoretical results. Based on this theoretical method, the breakdown phenomenon of the pulse microwave is analyzed. The results show that the product values of the initial electron density and the propagation length are the criterion to distinguish the pulse peak decline breakdown and the pulse width reduction breakdown. Furthermore, the energy transmission is also studied, which shows that the total output energy is approximately independent of the input electric field if the electric field is not extremely large.

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Multiple breakdown in helium generated by hybrid 10 ?m Co2 laser pulses

Cited by 8 publications

References 12 publications

Optical emission studies of nitrogen plasma generated by IR CO₂laser pulses

Optical emission studies of nitrogen plasma generated by IR CO₂laser pulses

Time-resolved optical emission spectroscopic measurements of He plasma induced by a high-power CO2 pulsed laser

Microwave propagation with the gas breakdown

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Multiple breakdown in helium generated by hybrid 10 ?m Co2 laser pulses

Cited by 8 publications

References 12 publications

Optical emission studies of nitrogen plasma generated by IR CO2laser pulses

Optical emission studies of nitrogen plasma generated by IR CO2laser pulses

Time-resolved optical emission spectroscopic measurements of He plasma induced by a high-power CO2 pulsed laser

Microwave propagation with the gas breakdown

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Product

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Optical emission studies of nitrogen plasma generated by IR CO₂laser pulses

Optical emission studies of nitrogen plasma generated by IR CO₂laser pulses