RT Dissertation/Thesis
T1 Electromagnetic properties of edge turbulence in fusion plasma devices
A1 Liu, Bing
AB This thesis work consists of three pillars. First, the isotope dependence of long-range correlation (due to, e.g. zonal flow and GAMs) has been studied in the TJ-II stellarator and ISTTOK tokamak with dual Langmuir probes. In TJ-II, it has been found that LRC slightly decreases with isotope mass, in contrast to tokamak results. In ISTTOK, GAM amplitude has been found to be higher in D than H dominated plasmas, in agreement with other tokamak results.Using biorthogonal decomposition (BOD), GAM and low frequency coherent modes were separated; their spectral and spatial structure properties were studied. In addition, measurements of Reynolds stress and Maxwell stress have been made using an electromagnetic probe during L-H transition in TJ-II. Second, macroscale flows and non-diffusive behavior of particle dynamics have been found around magnetic islands in TJ-II and RFX-mod with the analysis of long-range spatial and temporal correlation (Hurst exponent). In TJ-II, during dynamic configuration scan experiments, rational surfaces have been found to affect the development of long-range spatial and temporal correlation. In RFX-mod, LRC has been detected at both sides of the m=0 island. The possible relation between long-range temporal correlation (Hurst exponent) and the phase angle of magnetic perturbation was also studied.Third, a new strategy for studying plasma potential asymmetries in magnetic flux surface has been developed based on edge electrode biasing and probe measurements in TJ-II.
YR 2016
FD 2016-11
LK https://hdl.handle.net/10016/24426
UL https://hdl.handle.net/10016/24426
LA eng
NO Joint European Doctorate and Network in Fusion Science andEngineering (Università degli Studi di Padova)
NO To acknowledge that this work was supported by the European Commissionin the framework of the Erasmus Mundus International Doctoral College in Fusion Scienceand Engineering (FUSION-DC) and also supported in part by the Ministerio de Economiay Competitividad of Spain under project ENE2012-38620-C02-01.
DS e-Archivo
RD 5 may. 2024