北大核科学论坛第296期

报告题目:Transport experiments and modelling on JET and predictions for ITER scenarios

报告人:Dr.  Paola Mantica EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, UK; CNR – Istituto di Fisica del Plasma P. Caldirola, Milano, Italy

时间: 20161129日(星期二 )下午2:00-3:30

地点:北京大学物理楼南506

联系人:肖池阶(cjxiao@pku.edu.cn

樊铁栓(tsfan@pku.edu.cn

AbstractAfter an introduction to turbulent transport in tokamaks, the seminar will focus on recent results of heat and particle transport experiments in JET, and their use to validate theoretical models, in view of predicting ITER scenarios.

Core ion and electron heat transport has been studied in L-mode plasmas by means of ICRH heat flux scans and temperature modulation. These experiments have confirmed the importance of two transport mechanisms that are often neglected in modeling experimental results, but are crucial to reach agreement between theory and experiment and are bound to be significant in ITER. The first mechanism is the stabilizing effect that the gradient of the total pressure (including the fast ion component) has on ITG driven ion heat transport in non-linear electromagnetic gyro-kinetic simulations using GENE or GYRO. Such mechanism dominates over ExB flow shear in the core and needs to be included in quasi-linear models such as TGLF and QLK to increase their ability to capture the relevant physics. The second mechanism is the capability of small-scale ETG instabilities to carry a significant fraction of electron heat. Non-linear GENE single-scale simulations of ITG/TEMs show that the TEM flux is not enough to achieve good match with experiment. TEM stiffness is also much lower than the measured one. Multi-scale simulations using >10 million CPUh have confirmed the importance of ETG-driven electron heat flux in JET.

Measurements of impurity profiles have been compared with theory predictions. Light impurities, for which the turbulent transport component is dominant, exhibit a much larger variation of density gradients than predicted by gyro-kinetic theory. Heavy impurities instead are dominated by neo-classical transport and very good agreement between experiments and modeling is found when including poloidal asymmetries due to centrifugal effects in strongly rotating plasmas. W accumulation represents a problem, particularly in Hybrid scenarios that have peaked electron density and no sawtooth activity. The use of central ICRH helps controlling the W accumulation.

The ITER reference H-mode scenario (IP=15 MA, BT=5.3 T, NBI=33 MW, ICRH=20 MW – 2nd harmonic Tritium minority or ECRH=20 MW) has been simulated self-consistently using the advanced physics based models QLK ad TGLF. Peak temperatures ~ 20 keV and densities ~ 9 1019 m-3 are predicted, with a-power ~ 420 MW and Q~8. The time dynamics of density profiles evolution following pellet injection has been modeled in detail in order to optimize the fuelling capabilities.

报告人简介

After graduating at Università Statale di Milano (Milano, Italy), Paola Mantica carried out her research at the Institute of Plasma Physics of the National Research Council in Milano (IFP-CNR). Currently she is Senior Researcher at IFP-CNR.

The research activity carried out by P.Mantica lies within the frame of thermonuclear fusion research in tokamaks, focussing on the experimental investigation of core transport and numerical modelling of experimental results.  In particular, she has developed the use of perturbative techniques to study electron heat transport, and more recently applied these techniques also to toroidal momentum, particle and ion heat transport.  P.Mantica has worked in collaboration with several EU tokamaks, namely DITE (UK), RTP and TEXTOR (Netherlands), ASDEX-Upgrade (Germany), DIII-D (US). She has worked on the JET tokamak (UK) regularly since 1985, and with full time involvement since 2001. From 2001 to 2004 she has been the Deputy Task Force Leader of the EFDA JET Task Force T, and Task Force Leader from 2004 to 2007. She has been deeply involved in the EFDA-JET and then EUROfusion-JET experimental campaigns and has been Scientific Coordinator of several experimental sessions focussed on transport studies and Coordinator of modelling activities on JET data. She has been part of the EU Transport Task Force since the very beginning, and took part in the activity of the EFDA Transport Topical Group with various tasks. From 2010 to 2013 she has been Deputy Chair of the TTG and Responsible Officer of EFDA Area 4 (research on plasma rotation). From 2014 to 2016 she has been Chair of the EU Transport Task Force. She has also been Chair of the EFDA Remote Participation User Group. Since November 2014 she has been appointed for 3 years as Chair of the International Tokamak Physics Activity (ITPA) Transport & Confinement group, a worldwide collaboration addressing key issues for the construction and operation of ITER.

The scientific production by P.Mantica is documented in about 115 journal papers and 150 international conference proceedings. Her H-index is 31 according to ISI Web of knowledge. She had invited talks at EPS and APS Plasma Physics Conferences and oral presentations at IAEA FEC, besides invited talks at several transport workshops. She has chaired and organized several transport workshops and has chaired the EPS Plasmas Physics Conference in 2016.

P. Mantica has been supervisor of several Laurea and PhD theses on the topic of heat transport in plasmas.

 

Tel. +39-02-66173258      Fax +39-02-66173239

mailto:mantica@ifp.cnr.it http://www.ifp.cnr.it