Causality, intermittence, and crossphase evolution during confinement transitions in the TJ-II stellarator

In this work, we study spontaneous electron to ion root transitions in TJ-II using Langmuir probes. By scanning the probe position on a shot to shot basis, we reconstruct a spatiotemporal map of the evolution of important turbulent quantities in the plasma edge region. We pay particular attention to...

Descripción completa

Detalles Bibliográficos
Autores: van Milligen, Boudewijn, Carreras, Benjamin, Voldiner, Igor, Losada, Ulises, Hidalgo, Carlos
Tipo de recurso: artículo
Fecha de publicación:2024
País:España
Institución:Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT)
Repositorio:Docu-menta. Repositorio Institucional del CIEMAT
Idioma:inglés
OAI Identifier:oai:dnet:documenta___::e457a2074a48a6b6a3b829dac49c16d3
Acceso en línea:https://hdl.handle.net/20.500.14855/2289
Access Level:acceso abierto
Descripción
Sumario:In this work, we study spontaneous electron to ion root transitions in TJ-II using Langmuir probes. By scanning the probe position on a shot to shot basis, we reconstruct a spatiotemporal map of the evolution of important turbulent quantities in the plasma edge region. We pay particular attention to the evolution of the cross phase between transport-relevant variables, showing the spatiotemporal evolution of this quantity for the first time, revealing the outward propagation of the changes associated with the transition. We also compute the intermittence parameter, which allows us to conclude that the turbulence, although its amplitude increases, condenses in a reduced number of dominant modes and becomes less bursty. The causal relationship between variables is studied using the transfer entropy, clarifying the interactions between the main variables and offering a rather complete picture of the complex evolution of the plasma across the confinement transition.