Unit:
Department of PhysicsLibrary of the School of Science
Dissertation committee:
1) Ιωάννης Τίγκελης, Καθηγητής, Φυσικής, ΕΚΠΑ
2) Δημήτριος Φραντζεσκάκης, Καθηγητής, Φυσικής, ΕΚΠΑ
3) Έκτορας Νισταζάκης, Αναπληρωτής Καθηγητής,Φυσικής, ΕΚΠΑ
4) Ευγενία Ροδίτη, Επίκουρη Καθηγήτρια, Φυσικής, ΕΚΠΑ
5) Ιωάννης Κομίνης, Επίκουρος Καθηγητής, ΗΜΜΥ, ΕΜΠ
6) Ηλίας Γλύτσης,Καθηγητής, ΗΜΜΥ, ΕΜΠ
7) Παναγιώτης Φράγκος,Καθηγητής, ΗΜΜΥ, ΕΜΠ
Original Title:
Φαινόμενα Σκέδασης σε Μέσα με Ανισοτροπία και Ανομοιογένεια με Εφαρμογές στην Ελεγχόμενη Θερμοπυρηνική Σύντηξη
Translated title:
Scattering Phenomena in Anisotropic and Non-Uniform media with Application to Controlled Thermonuclear Fusion
Summary:
Controlled thermonuclear fusion is developed in order to replace the sources used up today for electrical power, since it is less environmentally effective. Fusion reactors are constructed by synthesizing complex in design subsystems. The gyrotron is one of the reactor’s subsystems which provides the power for the heating of the plasma core. Parasitic oscillations are developed in the gyrotron’s beam tunnel and its efficiency is decreased. The effect of the parasitic oscillations is studied for design which contain addition of lossy materials the beam tunnel. The propagation of the radiation form the gyrotron to the plasma core may be affected by the presence of density fluctuations.
Two commercially available simulation software were used for all the simulations. Specifically, the beam tunnel structure of continuous radius was simulated. The dielectric properties of the lossy inserts were considered to be lower than those of SiC. The quality factor and the parameter R/Q were calculated. The R/Q parameter was used as characterization factor for the beam-wave interaction. The simulations considered modes that are propagated in the opposite direction of the electrons from the source. The plasma dielectric properties were calculated based on the time dependency of the simulation software. Cases with circular design step and Gaussian density distributions were simulated as well as scattering from a sinusoidally modulated interface. Electron Cyclotron and Lower Hybrid modes were considered for cases with and without collisions in the calculations of the dielectric tensor.
Main subject category:
Science
Keywords:
Thermonuclear Fusion, Scattering, Plasma, Gyrotron, Numerical Simulations
File:
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AZisis_PhD.pdf
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