Gianpiero Colonna - Plasma Modeling Methods and Applications

Methods and Applications

Gianpiero Colonna

Consiglio Nazionale delle Ricerche (CNR), PLASMI Lab at NANOTEC, Bari, Italy

Antonio DAngola

Scuola di Ingegneria, Universit della Basilicata, Potenza, Italy and
Consiglio Nazionale delle Ricerche (CNR), PLASMI Lab at NANOTEC, Bari, Italy

IOP Publishing, Bristol, UK

IOP Publishing Ltd 2016

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Gianpiero Colonna and Antonio DAngola have asserted his right to be identified as the author of this work in accordance with sections 77 and 78 of the Copyright, Designs and Patents Act 1988.

ISBN 978-0-7503-1200-4 (ebook)
ISBN 978-0-7503-1201-1 (print)
ISBN 978-0-7503-1202-8 (mobi)

DOI 10.1088/978-0-7503-1200-4

Version: 20161201

IOP Expanding Physics
ISSN 2053-2563 (online)
ISSN 2054-7315 (print)

British Library Cataloguing-in-Publication Data: A catalogue record for this book is available from the British Library.

Published by IOP Publishing, wholly owned by The Institute of Physics, London

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IOP Plasma Physics Series

Richard Dendy

Culham Centre for Fusion Energy and the University of Warwick, UK

Uwe Czarnetzki

Ruhr-University Bochum, Germany

About the Series

The IOP Plasma Physics ebook series aims at comprehensive coverage of the physics and applications of natural and laboratory plasmas, across all temperature regimes. Books in the series range from graduate and upper-level undergraduate textbooks, research monographs and reviews.

The conceptual areas of plasma physics addressed in the series include:

• Equilibrium, stability and control
• Waves: fundamental properties, emission, and absorption
• Nonlinear phenomena and turbulence
• Transport theory and phenomenology
• Laser-plasma interactions
• Non-thermal and suprathermal particle populations
• Beams and non-neutral plasmas
• High energy density physics
• Plasma-solid interactions, dusty, complex and non-ideal plasmas
• Diagnostic measurements and techniques for data analysis

The fields of application include:

• Nuclear fusion through magnetic and inertial confinement
• Solar-terrestrial and astrophysical plasma environments and phenomena
• Advanced radiation sources
• Materials processing and functionalisation
• Propulsion, combustion and bulk materials management
• Interaction of plasma with living matter and liquids
• Biological, medical and environmental systems
• Low temperature plasmas, glow discharges and vacuum arcs
• Plasma chemistry and reaction mechanisms
• Plasma production by novel means

To Mariachiara, Gerardina, Michelangelo and Maria Teresa, our future.

In the last few years, research activity in the fields of plasma physics and chemistry has grown exponentially, not only focusing on fundamental aspects, but also on industrial applications. Due to its inherent complexity, both experiments and numerical modeling are necessary to fully characterize plasma systems. The most commonly used numerical simulation techniques for plasma modeling include fluid dynamics, kinetic, and hybrid models. These simulation models differ significantly in terms of their principles, strengths, and limitations. Kinetic models, such as particle-in-cell with Monte Carlo collisions, are used for non-equilibrium systems, and fluid models are employed for faster computations, reducing the accuracy. Hybrid models provide balance between precision and efficiency.

The golden age of plasma modeling occurred in the 1980s90s, when several research groups across the world developed theoretical and numerical approaches to investigate plasma behaviors. Currently, plasma modeling mainly addresses technological applications and, due to the complexity of systems, commercial multi-purpose codes are often used. These numerical codes are based on the fluid dynamics approach, describing realistic discharge geometries. COMSOL Multiphysics and ANSYS Fluent are examples of very popular commercial general-purpose software platforms, based on advanced numerical methods, for modeling and simulating physics-based problems. They are suitable for the design and development of optimized products by researchers and engineers working for leading technical enterprises, research laboratories, and universities. In strong non-equilibrium cases it is necessary to calculate the energy distribution function of particles. Kinetic modeling is recurrent in gas discharge investigations due to the non-equilibrium energy distribution of charged particles, which are not representable by the Maxwell distribution function, with abrupt changes in the slope, dumps and bumps, affecting the macroscopic properties of the plasma. In this context, a critical aspect is to determine the actual distribution function of free electrons, solving the Boltzmann equation. The electron energy distribution directly affects the plasma composition, also inducing non-equilibrium in internal states which, in turn, influences the electron gas, creating a strong synergy between the different plasma components. BOLSIG+, originally developed in the LAPLACE laboratory in Toulouse, is an example a freeware non-commercial code for the numerical solution of the Boltzmann equation for free electrons in weakly ionized gases in the framework of the two-term approximation.

Several non-commercial codes have been developed by research groups to simulate one- or two-dimensional problems and suitable plasma applications. It is worth mentioning nonPDPSIM, developed by the Kushner research group, which is is a two-dimensional computational platform that solves, using the hybrid approach, transport equations for charged and neutral species, Poissons equation for the electric potential, the electron energy conservation equation for the electron temperature, radiation transport and NavierStokes equations for the neutral gas flow, coupled with a Monte Carlo solver for the electron energy distribution function. The two-dimensional platform has three major modules addressing plasma dynamics, fluid dynamics, and surface kinetics, and is implemented on an unstructured mesh to enable resolution of a large dynamic range in space.

The aim of this book is to present a review of the different approaches that can be adopted to model a plasma, giving a comprehensive bibliography for students and researchers who want to start a project in plasma modeling, orienting the reader toward the choice of a suitable numerical method. The chapters in this book have been written by experienced researchers in the field, who have developed advanced theoretical models and high-performance numerical codes. The theoretical models used in commercial or freeware codes are described throughout this book, guiding students, researchers, and engineers in choosing the proper approach for the problem under investigation. This book describes the theoretical and numerical approaches that the plasma community currently uses to investigate plasmas, and thus can help the reader in creating a customized in-house code, particularly when commercial or freeware codes cannot be used.