Fusion Plasma Thermal Transport Radial and Poloidal Profile Modeling | Martin Olesen
| | Abstract | The present work constitutes a numerical study of the Critical Gradient Model (CGM) [21, 9, 22, 15, 24, 23] and the Turbulence Spreading Transport Model (TSTM) [28]. The CGM and TSTM are both heuristic models and are used for a much simplified description of plasma transport by turbulence. In particular, the propagation of thermal perturbations in two distinct types of experiments conducted in the Joint European Torus (shot 55809) are modeled: 1. Modulation of the off-axis localised ion cyclotron resonance heating source. 2. Cold pulse shock induction at the plasma edge via laser ablation. Until recently, no model that incorporates a self-consistent relation between the temperature gradients which drive fluctuations, and the turbulence intensity, has been able to describe both slow heat wave propagation from heat modulation and the fast propagation of a cold pulse, at the same plasma parameters. However, this has been successfully modeled with the TSTM [28].
After establishing a numerical scheme accommodating the special requirements of the CGM and TSTM dynamics, namely efficient handling of stiffness, the chosen scheme is verified. The CGM and TSTM are implemented numerically with Matlab using this scheme, and sought validated by comparing to experiment and results found in the literature [21, 28]. Through radial profile CGM investigations the 1-dimensional (1D) implementation is validated and thereby found fit for extension to include the poloidal cross-section of the modeled fusion plasma. The developed 2D poloidal plane implementation is verified against the 1D implementation. The impact on heat modulation and cold pulse simulation results due to the inclusion of the poloidal dynamics is investigated. A 2D scheme allowing for modeling arbitrary reactor geometries is presented. Reproduction of the TSTM results given in [28] is not achieved. | | Type | Master's thesis [Academic thesis] | | Year | 2011 | | Publisher | Technical University of Denmark, DTU Informatics, E-mail: reception@imm.dtu.dk | | Address | Asmussens Alle, Building 305, DK-2800 Kgs. Lyngby, Denmark | | Series | IMM-M.Sc.-2011-36 | | Note | | | Electronic version(s) | [pdf] | | BibTeX data | [bibtex] | | IMM Group(s) | Scientific Computing |
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