Suppression of the turbulent decay of an afterspark channel with residual current

Леонов, С.В.; Isaenkov, Yuri I.; Shneider, Mikhail N.

doi:10.1063/1.2825004

Cited by 20 publications

(7 citation statements)

References 14 publications

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“…The authors observed that the hot gas produced by a single spark propagated over a few millimeters within tens of microseconds. In further developments, Leonov et al [26] investigated high current (~1.5 kA) sparks of 50-ns duration across long interelectrode gaps (50-60 mm) in air, and observed the onset of strong turbulence attributed to Rayleigh-Taylor instabilities, with a radial expansion of the hot gas core to distances up to 50 times the radius of the initial spark channel. More recently, this effect was also observed in nanosecond sparks with lower current (~100 A) [27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Large-volume excitation of air, argon, nitrogen and combustible mixtures by thermal jets produced by nanosecond spark discharges

Stepanyan

Hayashi

Salmon

et al. 2017

Plasma Sources Sci. Technol.

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This work presents experimental observations of strong expanding thermal jets following the application of nanosecond spark discharges. These jets propagate in a toroidal shape perpendicular to the interelectrode axis, with high velocities of up to 30 m/s and over distances of centimeter scale. Their propagation length is much larger than the thermal expansion region produced by the conventional millisecond sparks used in car engine ignition, thus greatly improving the volumetric excitation of gas mixtures. The shape and velocity of the jets is found to be fairly insensitive to the shape of the electrodes. In addition, their spatial extent is found to increase with the number of nanosecond sparks and with the discharge voltage, and to decrease slightly with the pressure between 1 and 7 atm at constant applied voltage. Finally, this thermal jet phenomenon is observed in experiments conducted with many types of gas mixtures, including air, nitrogen, argon, and combustible CH 4 /air mixtures. This makes Nanosecond Repetitively Pulsed (NRP) discharges particularly attractive for aerodynamic flow control or plasma-assisted combustion because of their ability to excite very large volumes of gas.

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Section: Introductionmentioning

confidence: 99%

Large-volume excitation of air, argon, nitrogen and combustible mixtures by thermal jets produced by nanosecond spark discharges

Stepanyan

Hayashi

Salmon

et al. 2017

Plasma Sources Sci. Technol.

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“…It means that the global hydrodynamic flux is still directed towards the outside of the channel at this time, driven by the continuous energy deposition from the Joule heating in the plasma. As long as this heating remains sufficient to displace neutrals outside of the discharge channel, hydrodynamic instabilities at the boundary are prevented from forming 40 . The discharge is therefore inherently stable.…”

Section: Resultsmentioning

confidence: 99%

Long-lived laser-induced arc discharges for energy channeling applications

Point

Arantchouk

Thouin

et al. 2017

Sci Rep

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Laser filamentation offers a promising way for the remote handling of large electrical power in the form of guided arc discharges. We here report that it is possible to increase by several orders of magnitude the lifetime of straight plasma channels from filamentation-guided sparks in atmospheric air. A 30 ms lifetime can be reached using a low-intensity, 100 mA current pulse. Stability of the plasma shape is maintained over such a timescale through a continuous Joule heating from the current. This paves the way for applications based on the generation of straight, long duration plasma channels, like virtual plasma antennas or contactless transfer of electric energy.

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“…Analysis of the experimental data shows that the size of the perturbed region is several times larger than it has to be appeared if only conventional laminar or turbulent diffusion mechanisms were at play. Comparison of the measured channel radius and the channel radius calculated using the conventional model, 14,19,22 which does not account for jet formation, is shown in Fig. 6͑a͒.…”

Section: B Initial Afterspark Expansionmentioning

confidence: 98%