ORCID Profile
0000-0003-0749-9273
Current Organisations
Physique des interactions ioniques et moléculaires
,
University of Saskatchewan
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Publisher: IOP Publishing
Date: 17-04-2020
Publisher: IOP Publishing
Date: 2021
Abstract: This article deals with surface loss on quartz of atomic hydrogen (H) and its isotope deuterium (D) in a low-pressure (10 Pa) pulsed inductively coupled plasma. The atomic temporal decay in the post discharge is measured by two-photon absorption laser-induced fluorescence (TALIF). From the loss rate, the atomic surface loss probability is determined. In pure hydrogen or pure deuterium gas, no isotopic effect on surface kinetics has been observed and the surface loss probabilities of H and D were found to be almost identical and equal to ∼1.8%. However, despite the lack of difference in surface loss probability, a net isotopic effect on surface loss rate due to the mass difference between the isotopes is measured. Hydrogen atoms diffuse faster and have higher flux to the plasma chamber walls than deuterium atoms. Hydrogen atoms are therefore lost at higher rate than deuterium atoms. Based on the observed isotopic difference and on the comparison between H and D TALIF signals, the isotopic effects on H and D atom production are discussed.
Publisher: Informa UK Limited
Date: 02-2022
Publisher: IOP Publishing
Date: 06-04-2018
Publisher: IOP Publishing
Date: 16-03-2023
Abstract: Two-dimensional microparticle crystals can be formed in the sheath of a gas discharge plasma. Ions from the bulk plasma are accelerated in the sheath electric field, flowing past the grains to create a positive ion wake downstream from the grains. Interaction between the ion wake and neighboring grains creates additional coupling between oscillation modes and can trigger mode-coupling instability (MCI). In order to better understand MCIs, the interaction between dust grains and ion wakes must be understood however, the relationship between the discharge parameters and ion wake characteristics is unknown. A molecular dynamics simulation of ion dynamics and dust charging is used to self-consistently determine the dust charge and ion wake characteristics for different synthetic experimental conditions. It is found that the ion wake is strongly dependent on the background gas pressure but not affected much by the discharge power.
Publisher: AIP Publishing
Date: 12-2021
DOI: 10.1063/5.0063610
Abstract: The origin and nature of perturbations induced by a high-voltage pulse on plasma parameters and their relationship to operating conditions (power and pressure) in an argon inductively coupled radio frequency plasma device is explored. The plasma parameters are measured with two radio frequency compensated Langmuir probes positioned either vertically above the pulsing target or horizontally along the diameter of the chamber, in the same axial plane as the target and same distance from the RF antenna. Fluctuations are observed in electron density ne, temperature Te, and plasma potential Vpl following negative polarity high voltage pulses and propagate deep in the plasma and well after the end of the pulse. Time-resolved data results indicate that the perturbations are significantly d ened at higher power as well as when closer to the plasma RF coil. The perturbation litudes depart significantly from steady state values when the pulse litude exceeds 2.0 kV and increase with the increasing pulse litude. Perturbation litudes are also higher for target materials having larger secondary electron yield. Our experimental results suggest that the underlying mechanism of this perturbation could be plasma heating driven by d ing of a beam-plasma instability as a result of a beam of secondary electrons emitted by the target streaming into the plasma.
Publisher: IOP Publishing
Date: 15-11-2022
Abstract: Complex plasma is a state of soft matter where micrometer-sized particles are immersed in a weakly ionized gas. The particles acquire negative charges of the order of several thousand elementary charges in the plasma, and they can form gaseous, liquid and crystalline states. Direct optical observation of in idual particles allows to study their dynamics on the kinetic level even in large many-particle systems. Gravity is the dominant force in ground-based experiments, restricting the research to vertically compressed, inhomogeneous clouds, or two-dimensional systems, and masking dynamical processes mediated by weaker forces. An environment with reduced gravity, such as provided on the International Space Station (ISS), is therefore essential to overcome this limitations. We will present the research goals for the next generation complex plasma facility COMPACT to be operated onboard the ISS. COMPACT is envisaged as an international multi-purpose and multi-user facility that gives access to the full three-dimensional kinetic properties of the particles.
Publisher: IOP Publishing
Date: 06-07-2020
Publisher: American Physical Society (APS)
Date: 28-01-2022
Publisher: IOP Publishing
Date: 12-02-2019
Publisher: IOP Publishing
Date: 26-08-2020
Publisher: AIP Publishing
Date: 07-2022
DOI: 10.1063/5.0095103
Abstract: Two-dimensional measurements of magnetron discharge plasma parameters are used to calculate the forces applied to an isolated nanoparticle in conditions where nanoparticles are produced from cathode sputtering. Plasma spatial inhomogeneities, which are specific to magnetron discharges, also induce inhomogeneities in the charging mechanism and applied forces. It is shown that the nanoparticle transport is due to electric, thermophoretic and ion drag forces, and that the dominant one proportional to the nanoparticle size varies according to position. For a given plasma, these spatial differences explain the segregation of size in the nanoparticle deposits, which are observed inside the device.
No related grants have been discovered for Lenaic Couedel.