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Digital archive of theses discussed at the University of Pisa

 

Thesis etd-08152010-211337


Thesis type
Tesi di dottorato di ricerca
Author
DI PRINZIO, MATTEO
URN
etd-08152010-211337
Thesis title
Monte Carlo and Molecular Dynamics Simulations of Plasma-Material Interactions
Academic discipline
ING-IND/22
Course of study
SICUREZZA NUCLEARE E INDUSTRIALE
Supervisors
tutor Prof. Aquaro, Donato
correlatore Prof. Cerullo, Nicola
correlatore Prof. Forasassi, Giuseppe
Keywords
  • Density Functional Theory
  • Molecular Dynamics
  • Monte Carlo
  • Nuclear Fusion
  • Plasma Facing Materials
Graduation session start date
26/10/2010
Availability
Withheld
Release date
26/10/2050
Summary
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.
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