1 EXC/P8-08 Transport and Turbulence with Innovative Plasma Shapes in the TCV Tokamak B. Labit 1), A. Pochelon 1), M. Rancic 1), F. Piras 1), A. Bencze 1), A. Bottino 2), S. Brunner 1), Y. Camenen 3), P.K. Chattopadhyay 4), S. Coda 1), E. Fable 2), T.P. Goodman 1), S. Jolliet 5), A. Marinoni 1), L. Porte 1), B.F. McMillan 1), S. Yu. Medvedev 6), O. Sauter 1), V. S. Udintsev 7), L. Villard 1), and the TCV Team 1) Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association EURATOM-Confédération Suisse, CH-1015 Lausanne, Switzerland 1) Max-Planck-Institut für Plasmaphysik (IPP) Boltzmannstraße 2, Garching, Germany 2) CSFA, Dpt. of Physics, University of Warwick, Coventry, UK 3) Institute for Plasma Research, Bhat, Gandhinagar, Gujarat, India 4) Japan Atomic Energy Agency, Higashi-Ueno 6-9-3, Taitou, Tokyo 110-0015, Japan 5) Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Moscow, Russia 6) ITER Organization,13108 Saint-Paul-Lez-Durance CEDEX, France email contact of main author: benoit.labit@epfl.ch Abstract: We present recent results on turbulence measurements in TCV L-mode plasmas. It has been shown that the heat transport is reduced by a factor of two for a plasma at negative triangularity compared with a plasma at positive triangularity. This transport reduction is reflected in the reduction of the temperature fluctuation level, in the low frequency part of the spectrum (20-150 kHz), measured by correlation ECE in the outer equatorial plane. Moreover, the radial correlation length of the turbulence is typically reduced by a factor of two at negative triangularity compared with positive triangularity. Nonlinear gyrokinetic simulations predict that the TEM turbulence might be dominant for these TCV plasmas. The TEM induced transport is shown to decrease with decreasing triangularity and increasing collisionality. Both dependences are in fairly good agreement with experimental observations. We also report on an innovative divertor magnetic configuration: the snowflake (SF) divertor whose properties are expected to affect the local heat load to the divertor plates in particular during ELMs when compared with the classical single-null (SN) divertor. In L-mode plasmas, the intermittent particle and heat transport in the SOL is associated with the presence of "blobs" propagating in the radial direction. Intermittency is compared between SN and SF configurations by looking at the statistical properties of the ion saturation current J sat measured with Langmuir probes (LPs) in the LFS scrape-off layer. For ELMy H-mode SF plasmas, the time evolution of J sat during ELMs is estimated with LPs covering the strike- points target zones. 1. Introduction In a fusion reactor based on magnetic confinement, the energy transport in the plasma core has to be minimized in order to increase the energy confinement time to values that will satisfy the Lawson criterion. At present, the core transport exceeds the transport due to collisions by at least one order of magnitude and the excess is attributed to turbulence. Therefore it is crucial to know which instabilities create this turbulent state and to find ways to control them and to reduce the induced transport. In L-mode plasmas obtained in the Tokamak à Configuration Variable (TCV, R/a = 3.5, B t < 1.54 T), the energy confinement time increases when the plasma triangularity δ is decreased [1]. Dedicated experiments [2] have shown that the mid-radius electron heat diffusivity significantly decreases with decreasing triangularity and, for similar plasma conditions, only half of the ECRH power is required at δ = -0.4 compared with δ = +0.4 to obtain the same temperature profile. The electron heat transport level exhibits a continuous decrease with decreasing triangularity and increasing collisionality. These experimental results have motivated global linear gyrokinetic simulations [2]. For all plasma triangularities and toroidal wave numbers, local and global linear simulations indicate that the so-called trapped electron mode (TEM) is the dominant instability and the electron contribution to the total growth rate γ is more than 90%. The maximum transport level, estimated from the mixing length heat diffusivity is obtained for a toroidal mode number n ≈ 10 and the heat diffusivity decreases significantly towards negative