Anagrafe della ricerca

The main objective of this Enabling Research proposal is to determine how plasma filaments separate from the well-confined region, and to understand the role that magnetic reconnection plays in the separation of a filament as well as the transport of its energy content towards the divertor target. This project will be addressing the issue of magnetic reconnection during filament separation from three complementary perspectives: analytical theory, numerical computation, and experimental observations. This strategy benefits from ensuring strong interactions between theoretical, numerical and experimental experts. Understanding the physics of the filament separation has important practical implications as it determines how energy transport occurs in the proximity of the separatrix, where parallel heat fluxes to the divertor are large [28]. This project would provide an original and rigorous theoretical basis to shed some light on the way ELM, inter-ELM and L-mode filaments interact with material surfaces and how reconnection might accelerate fast particles toward the divertor targets. This is an important issue for reactor relevant machines, where such filaments will be larger and will contain more kinetic and magnetic energy, possibly resulting in larger divertor heat fluxes. Additionally, this project could improve the interpretation of some recent experimental observations. For example, the measurements of steeper heat flux profiles on JET limiters that led to the redesign of the ITER limiter [29], or the non-exponential decay of density profiles which induces stronger interaction with unprotected first wall surfaces [30], and the parametric dependence of upstream heat flux decay length, particularly its dependence on the magnetic configuration and its lack of dependence on the major radius [6]. The connection to experiments is a key aspect of the project, and one of the final goals is the comparison of numerical simulations and analytical models with experimental observations.