Summary on transport IAEA Technical Meeting, Trieste Italy Presented by A.G. Peeters Contents Toroidal momentum transport (S. Newton, A.G. Peeters, G. Falchetto [other session]) Gyro-kinetic calculations (Y.A. Sarazin, V. Grandgirard, G. Rewoldt, B. Scott) The Edge (M. Tokar, N. Kasuya, N. Bisai, J.J. Ramussen, V.I. Maslov, S. H. Mueller) Stabilization of turbulence P.K. Kaw S. Newton Redistribution of impurities changes toroidal momentum tranport Restricted to subsonic rotation to calculate neoclassical terms Z eff = 1 - recover Braginskii, Hinton & Wong results Most experimentally relevant limit: conventional aspect ratio, 2) lternative closure motivated by entropy production rates Works well in the linear regime (nonlinear ??) V. Grandgirard Interplay of density profile and zonal flow in slab ITG turbulence Semi Lagrangian method (Good energy conserv.) Currently 4D slab ITG Zonal flows are strongly connected with the background density gradient Density gradient both linearly as well as non- linearly stabilizing Extremely nice picture G. Rewoldt Progress in the development of the GTC code ETG studies (reviewed by T.S. Hahm?) General geometry Parallel velocity nonlinearity Electromagnetic effects Neoclassical studies B.D. Scott, Edge turbulence The Edge M. Tokar Density limits in tokamaks Alternative Mechanism for MARFE Formation: instability of plasma recycling on inner wall Plasma Flows B Plasma flows ||B Heat flux to the edge Charged particle losses to wall: Energy losses with particles: Neutrals Model for edge anomalous transport Linearized parallel Ohms, Faradays and Amperes law, ion momentum balance, quasi-neutrality, ion continuity equation Eigen function equation for electric potential perturbation of Mathieus type: DADRB MARFE at HFS: result of recycling instability at high heating when Shafranov shift dominates poloidal asymmetry Detachment at LFS: develops at lower heating power because of transition to anomalous transport driven by DRB- modes N. Kasuya Poloidal shock formation And particle transport in the H-mode N. Bisai and J.J. Rasmussen (2 independent papers) 2D SOL turbulence Formation of density blob Fig. From Bisai (2D cold ions, edge and SOL) Density blob forms near edge-to-SOL regions by the detachment from density streamer. In the SOL structures move mostly radially and eventually die out (small structures live shorter, not all move) From J.J.Rasmussen (2D SOL turbulence warm ions) V.I. Maslov Density transport due to convection and diffusion Equation for density evolution due to convective cells (finite lifetime) combined with diffusive regions Also propagation of the cells due to electric field was studied S. H. Mueller Experiments on TORPEX Important Parameter: The Vertical Magnetic Field B z B BB v B,e v B,i E Toroidicity drifts lead to charge separation and electric fields F = -eE || Generation of Parallel flows Short circuiting of electric field Collisions inhibit parallel motion Equilibrium B cscs Sheath parallel loss sin E ExB loss 1/sin 2 Competition between two basic loss channels: Implications for confinement Important mechanism Theory and measurement of confinement time: S. H. Mller et al, PRL 2004 Important role of B z for basic confinement Profiles as a Function of B z 1 Shot = 1 Profile = 1 Movie Frame P.K. Kaw Stabilization of turbulence with RF waves Use of the ponderomotive force of the wave field to compensate the unfavourable curvature force Stabilization of turbulence (over a region of the size of the skin depth) for ITER like parameters is possible using 10 MW RF Reduction due to the change of chaotic behaviour through the introduction of small perturbations in the electric field