"Control system-plasma synchronization and naturally occurring edge localized tokamak modes"
Sandra C Chapman
University of Warwick/Boston University/2017-18 Fulbright Lloyd’s of London Scholar
A ubiquitous aspect of strongly connected, many component systems is the potential for self- organisation to synchronous states, in the sense of nonlinear active feedback between global and local scales which leads to the emergence of global spatio-temporal coherent dynamics. Tokamak experiments for magnetically confined fusion (MCF) support large-scale plasmas with nonlinear coupling of plasma physics processes over several orders of magnitude in length and timescales. Emergent phenomenology is found in these large scale plasma systems: they self-organise to generate large scale structures and flows with enhanced high confinement, known as H-mode. Edge localized modes (ELMs) are intense, short duration relaxation events observed in tokamak H-mode regimes. Typically, in present day devices a few hundred ELMs occur naturally in the quasi-stationary phase of H-mode plasmas. Each ELM releases particles and energy which load the plasma facing components; scaled up to ITER, the largest such loads would be unacceptable.
