Electro-Hydrodynamics of Micro-Discharges in Gases at Atmospheric Pressure

Eichwald, Olivier; Yousfi, Mohammed; Ducasse, Olivier; Merbahi, Nofel; Sarrette, Jean‐Philippe; Meziane, M.; Benhenni, Malika

doi:10.5772/28929

Cited by 8 publications

(10 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Simulations by Marode et al [42] have shown that streamer discharges heat air and initiate a radial air flow lowering the air density close to the streamer by up to approximately 50% within some tens of ns. Such air perturbations have been confirmed by more recent simulations and experiments showing that streamer and spark discharges perturb proximate air up to 80% [43,44,45,46,47]. In previous work, we have examined streamer properties and modelled the production of runaway electrons and the emission of X-rays from streamers in perturbed air [48,49].…”

Section: Introductionsupporting

confidence: 62%

The emission of energetic electrons from the complex streamer corona adjacent to leader stepping

Köhn

Chanrion

Nishikawa

et al. 2020

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

We here propose a model to capture the complexity of the streamer corona adjacent to leader stepping and relate it to the production of energetic electrons serving as a source of X-rays and γ-rays, manifesting in terrestrial gamma-ray flashes (TGFs). During its stepping, the leader tip is accompanied by a corona consisting of multitudinous streamers perturbing the air in its vicinity and leaving residual charge behind. We explore the relative importance of air perturbations and preionization on the production of energetic run-away electrons by 2.5D cylindrical Monte Carlo particle simulations of streamers in ambient fields of 16 kV cm −1 and 50 kV cm −1 at ground pressure. We explore preionization levels between 10 10 m −3 and 10 13 m −3 , channel widths between 0.5 and 1.5 times the original streamer widths and air perturbation levels between 0% and 50% of ambient air. We observe that streamers in preionized and perturbed air accelerate more efficiently than in non-ionized and uniform air with air perturbation dominating the streamer acceleration. We find that in unperturbed air preionization levels of 10 11 m −3 are sufficient to explain run-away electron rates measured in conjunction with terrestrial gamma-ray flashes.

show abstract

Section: Introductionsupporting

confidence: 62%

The emission of energetic electrons from the complex streamer corona adjacent to leader stepping

Köhn

Chanrion

Nishikawa

et al. 2020

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…We used the constant in ref [1] , A=7.04 (cm-1 Torr-1 ), B=11.2(V/cm Torr)0.4 ,and p is the pressure.…”

Section: Physical Constantsmentioning

confidence: 99%

“…For electric field and density distribution, the basic numbers are given in [1,2,3]. We used the max AC voltage where n e and n i are electron and ion densities, and E i is the electric field and ε is the permittivity.…”

Section: Physical Constantsmentioning

confidence: 99%

“…The original form of the enthalpy equation is given in [1]. We dropped the viscous and conductivity terms and assumed a perfect gas, to obtain a form along the streamline as Following Bolonkin's energy model [3], we assumed the portion of total energy to 50% and 50% for the thermal and electron energy productions.…”

Section: Modeling On the Energy Equationmentioning

confidence: 99%

“…However, some successful computation models [1,2] have been presented for simple cases by conducting fundamental experiments.Specifically, in fluid mechanics, the experiments showed the occurrence of: 1) two regions of ionic and neutral gas, 2) a shock wave, 3) heat generation with high temperature in nanoseconds, and 4) jet generation. The velocity of the jet is about 5 to 10m/sec and the thickness of the jet is a few mm.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling of the Heat Interface of a Plasma Actuator

Obikane¹,

Lochin²

2015

Procedia Engineering

View full text Add to dashboard Cite

We simulated a one-dimensional plasma actuator (PA) with a dielectric layer by using the electric potential equation, the electron and ion density conservation equations, and the enthalpy equation. We then derived the correlation of electron and ion density using the Navier Stokes equation and the enthalpy equation and modeled it using the Reynolds decomposition. We also made an energy model interpretation of the differential system at the initial state. The computation results show that the gradient of the correlation of the electron density and electric field was nearly constant in space; therefore, gradient transport modeling can be applied. An experiment conducted to confirm the existence of the phenomena successfully revealed the intermittent jets. We used our experimental configuration to compute two-dimensional flows, and we obtained an induced periodic jet flow. We also observed cylindrical waves emitted from the trailing edge of the anode. We have successfully extracted fine structures of the PA, including its aero-acoustic property

show abstract

High‐Energy Emissions Induced by Air Density Fluctuations of Discharges

Köhn

Chanrion

Neubert

2018

Geophysical Research Letters

View full text Add to dashboard Cite

Bursts of X‐rays and γ‐rays are observed from lightning and laboratory sparks. They are bremsstrahlung from energetic electrons interacting with neutral air molecules, but it is still unclear how the electrons achieve the required energies. It has been proposed that the enhanced electric field of streamers, found in the corona of leader tips, may account for the acceleration; however, their efficiency is questioned because of the relatively low production rate found in simulations. Here we emphasize that streamers usually are simulated with the assumption of homogeneous gas, which may not be the case on the small temporal and spatial scales of discharges. Since the streamer properties strongly depend on the reduced electric field E/n, where n is the neutral number density, fluctuations may potentially have a significant effect. To explore what might be expected if the assumption of homogeneity is relaxed, we conducted simple numerical experiments based on simulations of streamers in a neutral gas with a radial gradient in the neutral density, assumed to be created, for instance, by a previous spark. We also studied the effects of background electron density from previous discharges. We find that X‐radiation and γ‐radiation are enhanced when the on‐axis air density is reduced by more than ∼25%. Pre‐ionization tends to reduce the streamer field and thereby the production rate of high‐energy electrons; however, the reduction is modest. The simulations suggest that fluctuations in the neutral densities, on the temporal and spacial scales of streamers, may be important for electron acceleration and bremsstrahlung radiation.

show abstract

Electro-Hydrodynamics of Micro-Discharges in Gases at Atmospheric Pressure

Cited by 8 publications

References 36 publications

The emission of energetic electrons from the complex streamer corona adjacent to leader stepping

The emission of energetic electrons from the complex streamer corona adjacent to leader stepping

Modeling of the Heat Interface of a Plasma Actuator

High‐Energy Emissions Induced by Air Density Fluctuations of Discharges

Contact Info

Product

Resources

About