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Title: Non-linear instabilities in the edge of tokamak plasmas : characterization of edge localized modes and numerical simulation of blob dynamics using a hybrid model
Author: Calderon, F. A.
ISNI:       0000 0004 5915 7686
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2015
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Characterization of edge tokamak plasma instabilities by measuring emergent phenomena within a range of frequencies above the ion cyclotron frequency have been explored in two ways: using the inter-event waiting times of Edge Localized Modes (ELMs) occurrences in measured time series of JET plasmas and by performing 2D/3D simulations of filamentary structures dynamics using a hybrid model plasma description, i.e. kinetic ion particles and massless charge neutralizing electron fluid. The analysis of ELMs time series using characteristic emission lines Da of JET tokamak in otherwise similar plasmas was performed with only a minimal number of drivers such as the gas puffing rate. They have shown a key role in changing the underlying system mode cycle where a threshold value revealed its transition from single harmonic behaviour to a transitioning phase into a total lost of the state and born of a higher frequency resonant mode. Hybrid simulations of blobs/filaments are performed in 2D/3D to observe the kinetic evolution of these plasma structures over several ion gyroperiods. Novel 3D simulations represent the first kinetic simulations of these structures along the parallel direction using a kinetic description. We have investigated the evolution and the internal density currents which provide insight of the effects of finite Larmor radius in the blobs dynamics and evolution.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QC Physics