ETD system

Electronic theses and dissertations repository


Tesi etd-08152010-211337

Thesis type
Tesi di dottorato di ricerca
Monte Carlo and Molecular Dynamics Simulations of Plasma-Material Interactions
Settore scientifico disciplinare
Corso di studi
tutor Prof. Aquaro, Donato
correlatore Prof. Cerullo, Nicola
correlatore Prof. Forasassi, Giuseppe
Parole chiave
  • Monte Carlo
  • Nuclear Fusion
  • Molecular Dynamics
  • Plasma Facing Materials
  • Density Functional Theory
Data inizio appello
Data di rilascio
Riassunto analitico
The design of a suitable interface between plasma heated at millions of kelvin
and the environment is one of the most critical areas within nuclear fusion research.
The surface of interface components should sustain the energy delivered
by plasma as electromagnetic radiation and transported through charge carriers
such as ions and electrons.
The ratio between available plasma energy and heated surface increases with
device dimension, so that for ITER and future fusion reactors the energy density
striking the tokamak walls will be order of magnitude higher compared to what
happens in current facilities.
Several plasma material interaction phenomena are relevant for PFCs design.
The high energy heavy particles striking the chamber walls produce sputtering.
The magnetic con nement su er from frequent plasma instabilities, which result
in a fast release of plasma energy on Plasma Facing Components. The ensuing
thermal and mechanical actions produce material damage, erosion, thermal
ablation and melting. Components lifetime is strongly limited by such extreme
phenomena and require careful design and material selection to avoid unwanted
maintenance stops and replacements.
The main aim of this research activity is to evaluate the PFMs erosion due to
thermal ablation, to understand how material properties are a ected by plasma
interactions and how correctly select PFMs, without relying simply on empiric
correlations with limited validity.
The main part of the performed work consist in the development of Molecular
Dynamics and Monte Carlo Simulation aimed to evaluate the thermal properties
of PFMs and to investigate how high energy electrons produced within the
plasma carry energy towards tokamak chamber walls.
The analysis of Plasma Material Interactions has been historically carried
out by putting together experimental activity and empiric relationships accounting
for complex physical e ects in an approximate fashion. The current research
activity wants to investigate such phenomena starting from the underlying physical
basic principles and through a comparison with experimental data with
minimum employ of empiric relationship.