Investigation of triggering mechanism of internal transport barriers on the Alcator C-Mod tokamak using Thomson scattering diagnostic
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2007.
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | eng |
| Published: |
Massachusetts Institute of Technology
2009
|
| Subjects: | |
| Online Access: | http://hdl.handle.net/1721.1/44790 |
| _version_ | 1826214534067519488 |
|---|---|
| author | Zhurovich, Kirill |
| author2 | Catherine Fiore. |
| author_facet | Catherine Fiore. Zhurovich, Kirill |
| author_sort | Zhurovich, Kirill |
| collection | MIT |
| description | Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2007. |
| first_indexed | 2024-09-23T16:07:16Z |
| format | Thesis |
| id | mit-1721.1/44790 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T16:07:16Z |
| publishDate | 2009 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/447902019-04-12T20:24:51Z Investigation of triggering mechanism of internal transport barriers on the Alcator C-Mod tokamak using Thomson scattering diagnostic Zhurovich, Kirill Catherine Fiore. Massachusetts Institute of Technology. Dept. of Nuclear Science and Engineering. Massachusetts Institute of Technology. Dept. of Nuclear Science and Engineering. Nuclear Science and Engineering. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2007. Includes bibliographical references. Internal transport barriers (ITBs) in tokamak plasmas are characterized by the reduction of transport in one or more of the particle, momentum, or energy channels in the core plasma region. On Alcator C-Mod, significant contributions to ITB studies were made possible with the core Thomson scattering (TS) diagnostic, which measures profiles of electron temperature (0.03 </= Te[keV] </= 10) and density (0.05 </= ne[1020m-3] </= 5) with ~1 cm resolution in the ITB region. For the transport analysis purposes, TS profiles are complemented by measurements from other diagnostics and fitted with smooth curves. This thesis research examines the plasma conditions necessary to trigger ITBs on C-Mod. ITBs can be routinely produced in C-Mod steady enhanced D[alpha] (EDA) high-confinement (H-mode) plasmas by applying off-axis ion cyclotron range of frequencies (ICRF) heating (Ir/al </= 0.5). They are observed primarily in the electron particle channel and are marked by the steepening of the density and pressure profiles. ITB formation in C-Mod appears to be the result of competition between an inward particle pinch and the outward diffusion caused by various fine scale plasma instabilities. Several experiments were performed on C-Mod to verify whether ITB formation can be explained within a paradigm of marginal stability. Analyses of the temperature profiles reveal that the Ti profile widens and the Te profile exhibits flattening in the ITB region when the ICRF resonance is moved off-axis. Transport and gyrokinetic stability analyses demonstrate that reduction of the temperature gradient suppresses the temperature gradient driven instabilities. Nonlinear gyrokinetic simulations of plasma microturbulence show that this results in a significant reduction of the outward diffusion, and allows the inward particle pinch to dominate, peaking the density profile. by Kirill Zhurovich. Ph.D. 2009-03-16T19:43:20Z 2009-03-16T19:43:20Z 2007 2007 Thesis http://hdl.handle.net/1721.1/44790 300308328 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 185 p. application/pdf Massachusetts Institute of Technology |
| spellingShingle | Nuclear Science and Engineering. Zhurovich, Kirill Investigation of triggering mechanism of internal transport barriers on the Alcator C-Mod tokamak using Thomson scattering diagnostic |
| title | Investigation of triggering mechanism of internal transport barriers on the Alcator C-Mod tokamak using Thomson scattering diagnostic |
| title_full | Investigation of triggering mechanism of internal transport barriers on the Alcator C-Mod tokamak using Thomson scattering diagnostic |
| title_fullStr | Investigation of triggering mechanism of internal transport barriers on the Alcator C-Mod tokamak using Thomson scattering diagnostic |
| title_full_unstemmed | Investigation of triggering mechanism of internal transport barriers on the Alcator C-Mod tokamak using Thomson scattering diagnostic |
| title_short | Investigation of triggering mechanism of internal transport barriers on the Alcator C-Mod tokamak using Thomson scattering diagnostic |
| title_sort | investigation of triggering mechanism of internal transport barriers on the alcator c mod tokamak using thomson scattering diagnostic |
| topic | Nuclear Science and Engineering. |
| url | http://hdl.handle.net/1721.1/44790 |
| work_keys_str_mv | AT zhurovichkirill investigationoftriggeringmechanismofinternaltransportbarriersonthealcatorcmodtokamakusingthomsonscatteringdiagnostic |