F. Militello M. Ottaviani A. Wynn
Unstable electrostatic resistive modes, driven by density gradients, are identified in a bounded sheared slab. The boundary conditions play a crucial role and are shown to change the nature of the problem, which is related to so called “universal” mode. The dispersion relation and the structure of the eigenmodes of the instability are derived a…
PublishedF. Militello V. Naulin A.H. Nielsen
Numerical simulations of L-mode turbulence in the Scrape-Off Layer (SOL) are used to construct power scaling laws for the characteristic decay lengths of the temperature, density and heat flux at the outer midplane. Most of the results obtained are in qualitative agreement with the experimental observations despite the known limitation of the model…
PublishedF. Militello P. Tamain W. Fundamenski A. Kirk V. Naulin A.H. Nielsen The Mast Team
Numerical simulations of interchange turbulence in the Scrape-Off Layer are performed in a regime relevant for a specific L-mode MAST (Mega Ampere Spherical Tokamak) discharge. Such a discharge was diagnosed with a reciprocating arm equipped with a Gundestrup probe. A detailed comparison of the average and statistical properties of the simulated an…
PublishedG. Szepesi M. Romanelli F. Militello A.G. Peeters Y. Camenen F.J. Casson W.A. Hornsby A.P. Snodin D. Wagner The Ftu Team
The impact of lithium impurities on the microstability and turbulent transport characteristics in the core of a typical FTU Liquid Lithium Limiter (LLL) (Mazzitelli et al., Nucl. Fusion, 2011) discharge during the density ramp-up phase is studied. A non-linear gyrokinetic analysis performed with GKW (Peeters et al., Comp. Phys. Comm., 2009) accompa…
PublishedF. Militello W. Fundamenski V. Naulin A.H. Nielsen
Numerical simulations of L-mode plasma turbulence in the Scrape Off Layer of MAST are presented. Relevant features of the boundary plasma, such as the thickness of the density layer or the statistics of the fluctuations are related to the edge density and temperature, plasma current and parallel connection length. It is found that the density profi…
PublishedW. Fundamenski F. Militello D. Moulton D.C. Mcdonald
A new model of the L–H transition in tokamaks is proposed, based on the criterion that the transition occurs when plasma turbulence and shear Alfvén waves compete in the vicinity of the last-closed flux surface. The model is used to predict the scaling of the H-mode access power, PL–H, with magnetic and plasma variables. The predictio…
PublishedW.Fundamenski T.Eich D.Moulton F.Militello C.Lowry G.Maddison E.Havlickova D.Ward R.Kemp M.Wischmeier D.C.Mcdonald
Recent infra-red measurements of divertor power loads on JET and AUG [1], revealed that the inter-ELM power width at the outer mid-plane in attached ELMy H-modes does not exhibit any noticeable scaling with machine size [1]. Making use of these results to calculate the effective radial heat diffusivity, and then including this in parametrized expre…
PublishedF. Militello W.Fundamenski V. Naulin A.H. Nielsen
The L-mode interchange turbulence in the edge and Scrape Off Layer of the tight aspect ratio tokamak MAST is investigated numerically. The dynamics of the boundary plasma is studied using the 2D drift-fluid code ESEL, which has previously shown good agreement with large aspect ratio machines. In this context, a MAST-TCV comparison is presented in o…
PublishedF. Militello W. Fundamenski
The behaviour of the turbulence in magnetic fusion plasmas is discussed in the framework of dimensional analysis. Three main dimensionless parameters are identified, which directly affect the adiabatic response of the plasma and hence control the electron response. They were originally introduced by Scott [B. Scott, Plasma Phys Control. Fusion, 39,…
Published