Electron transport modeling in gas and liquid media for application in plasma medicine

Garland, Nathan Ashley (2018) Electron transport modeling in gas and liquid media for application in plasma medicine. PhD thesis, James Cook University.

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View at Publisher Website: https://doi.org/10.25903/5bf38aee6e2a4
 
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Abstract

Emerging plasma technologies, such as plasma medicine, rely on the transport of plasma species across gas-liquid interfaces to achieve their function. Recent studies have identified that, while poorly understood at present, electron transport through the interface is an important driver of plasma chemistry in plasma medicine. In order to understand this fundamental transport, so to facilitate understanding and future optimisation of plasma technologies, a modeling framework for electron transport simulations across gas-liquid interfaces has been developed. This modeling framework has been been applied to noble liquids, such as argon and xenon, and the first steps have been made towards application to a biomolecule system involving tetrahydrofuran.

This research has extended previous approaches to electron fluid modeling in the gas phase to propose a fluid model for electron transport in gas and liquid media based on four moments of the Boltzmann kinetic equation. The model was benchmarked against kinetic solutions of electron transport to validate the applicability of the model to describe non-local electron transport phenomena in both gas and liquids, given that appropriate and accurate input data is available. To assess the impact of employing steady-state collision and closure input data in electron fluid models, non-equilibrium velocity distribution functions, computed via multi-term solution of the Boltzmann equation for benchmark calculations, were studied.

The dependence of the proposed model's input transport data on the background medium density was examined in this research. By examining how electron momentum and energy transfer occurs due to collisions in gas and liquid extremes, an approximation method was proposed to generate input transport data at intermediate densities for which data is required, but not available, for modeling interfacial transport. The proposed approximation was benchmarked against analytic simple liquids and experimental data measured in cryogenic argon and xenon to verify the applicability of the proposed approach.

Simulations of electron transport between gas and liquid argon, and vice versa, was performed by applying both the proposed fluid model and input data approximation method. Comparisons of the abilities of modeling methods to resolve realistic non-local transport were studied, and the stark differences between using electron-liquid transport data compared to simply scaling up electron-gas transport data were discussed. Application of this modeling framework to dual-phase simple liquid particle detector apparatus was demonstrated.

Finally, application of the developed modeling framework was made to electron transport in tetrahydrofuran. To do so, a complete gas phase electron scattering cross section set was assembled and analysed using available experimental and theoretical data. Modifications of gas phase scattering to a simulated liquid phase were made using available experimental data. Comparison of streamer formation and propagation in both gaseous and simulated liquid tetrahydrofuran was studied to demonstrate applicability of the framework developed in this research to electron transport in biologically relevant soft-condensed matter.

Item ID: 56157
Item Type: Thesis (PhD)
Keywords: coherent scattering, common mean energy, electron transport, fluid model closure, fluid model, fluid modeling, gas and liquid discharges, interface, low temperature plasma, momentum transfer theory, non-local transport, plasma-liquid, structured media
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Copyright Information: Copyright © 2018 Nathan Ashley Garland
Additional Information:

Publications arising from this thesis are available from the Related URLs field. The publications are:

Chapter 2: Garland, N.A., Cocks, D.G., Boyle, G.J., Dujko, S., and White, R.D. (2017) Unified fluid model analysis and benchmark study for electron transport in gas and liquid analogues. Plasma Sources Science and Technology, 26 (7). pp. 1-16.

Chapter 3: Garland, Nathan, Boyle, Greg, Cocks, Daniel, and White, Ron (2018) Approximating the nonlinear density dependence of electron transport coefficients and scattering rates across the gas–liquid interface. Plasma Sources Science and Technology, 27.

Chapter 5: Garland, N.A., Brunger, M.J., Garcia, G., de Urquijo, J., and White, R.D. (2013) Transport properties of electron swarms in tetrahydrofuran under the influence of an applied electric field. Physical Review A (Atomic, Molecular and Optical Physics), 88. pp. 1-10.

Date Deposited: 20 Nov 2018 04:42
FoR Codes: 02 PHYSICAL SCIENCES > 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics > 020299 Atomic, Molecular, Nuclear, Particle and Plasma Physics not elsewhere classified @ 35%
02 PHYSICAL SCIENCES > 0204 Condensed Matter Physics > 020499 Condensed Matter Physics not elsewhere classified @ 30%
02 PHYSICAL SCIENCES > 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics > 020204 Plasma Physics; Fusion Plasmas; Electrical Discharges @ 35%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970102 Expanding Knowledge in the Physical Sciences @ 100%
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