INSTITUTO DE PLASMAS E FUSÃO NUCLEAR

WORK-PROGRAMME FOR 2008

IPFN, January 2008

1

1. INTRODUCTION

The 2008 scientific and technical activities of “Instituto de Plasmas e Fusão Nuclear” (IPFN) will be mainly focussed in the following projects:

  • Tokamak ISTTOK;
  • Participation in the collective use of the JET facilities by the EFDA Associates;
  • Participation in the ASDEX Upgrade programme;
  • Participation in the TJ-II programme;
  • Participation in the TCV programme;
  • Collaboration with the Association EURATOM/CEA;
  • Participation in the COMPASS-D programme;
  • Other studies on theory and modelling;
  • Other activities on data acquisition and real-time plasma control;
  • Participation in the Fusion Technology Programme;
  • Participation in the ITER construction;
  • Keep-in-touch activities on inertial fusion energy;
  • Other Fusion-related activities;
  • Plasma Simulation and Theory;
  • High Intensity Photonics and Laser-Plasma Experiments;
  • Fundamental Physics in Space;
  • Mathematical Physics and Quantum Computing;
  • Environmental Engineering Plasma Laboratory;
  • Nonequilibrium Kinetics and Simulations of Plasmas and Afterglow Plasmas;
  • Modelling of Plasma Sources;
  • Plasma and Electromagnetic Propulsion;
  • Quantum Plasmas,

carried out in the frame of the Contract of Associated Laboratory signed between “Fundação para a Ciência e a Tecnologia” (FCT) and “Instituto Superior Técnico” (IST). The first thirteen projects are also funded by the Contract of Association between the European Atomic Energy Community (EURATOM) and IST as well as by the European Fusion Development Agreement (EFDA).

The above mentioned projects are performed by staff (70 Ph.D. Researchers and 75 Researchers, Engineers and Fellows) with Ph.D belonging to six Scientific Groups:

  • Experimental Physics on Magnetic Confinement (Head: Horácio Fernandes);
  • Microwave Diagnostics for Fusion Plasmas (Head: Maria Emília Manso);
  • Theory and Modelling of Magnetic Confinement Fusion Plasmas (Head: Fernando Serra);
  • Control and Data Acquisition (Head: Jorge Sousa);
  • Lasers and Plasmas (Head: Luis Oliveira e Silva);
  • Electronics and Gas Discharges (Head: Carlos Matos Ferreira).

2. TOKAMAK ISTTOK[1],[2]

This project will include activities in the areas of study of fusion relevant materials, diagnostics, control and data acquisition, and plasma physics studies.

2.1. Study of fusion relevant materials

The following tasks are planned: (i) Installation of a multi-jet gallium system to generate a 1 cm width gallium limiter aiming at a more efficient heat removal[3]; (ii) Modelling of the interaction of a gallium jet with the plasma SOL (for application in FTU); (iii) Installation, testing and calibration of a multi-channel infra-red sensor to measure the increase of gallium surface temperature due to the interaction with the ISTTOK plasma; (iv) Improvement of the consolidation of W-nD nanocomposided to achieve higher densities; and (v) Detailed characterization of W-nD samples exposed to the plasma using electron microscopy and atomic force microscopy techniques (also at FTU).

2.2. Diagnostics

The following activities are foreseen: (i) Upgrade of the time of flight energy analyser of the heavy ion beam diagnostic by shielding the channeltrons from the plasma radiation, which will allow an increase of the signal-to-noise ratio; (ii) Further studies on the ISTTOK plasma emissivity reconstruction using analytical and neural networks methods with the aim of performing fast tomographic reconstructions methods; (iii) Measurement of the fluctuations from the HIBD and tomography diagnostics; and (iv) Test of a heat flux sensitive detector for power deposition studies on ISTTOK.

2.3. Control and data acquisition

The following tasks are envisaged: (i) Development of a new version of the SDAS software to allow dynamic sample rates, according to the specifications agreed with CIEMAT; (ii) Installation of a 64 input channels control system (based on the ATCA standard) on the plasma position controller to provide better than 16-bit ENOB digitalization resolution and to allow the integration of the tomography with the MHD current profile reconstructions, for a better plasma control during AC inversion experiments; (iii) Migration of the plasma position node of the new ATCA system that will allow the test of new concepts for the COMPASS control and data acquisition system; (iv) Development of a new unit, based on a low-cost dsPIC microcontroller, to allow real-time density measurements and (vi) Development of a module for low-speed event propagation that will allow the communication between the fast timing/synchronization/event system and the slow control systems such as the vacuum and gas injection controllers.

2.4. Plasma physics studies

The following activities will be carried out: (i) Operation of the tokamak ISTTOK in multi-cycle alternating plasma current regime; (ii) Detailed study of the plasma parameters during the current reversal. In particular, study how profiles evolve during the plasma current reversalowHow the Ho; (iii) Edge physics studies (recycling and power exhaust) in long-time AC discharges in ISTTOK; (iv) Detailed characterization of the space-time structure of the edge fluctuation using Langmuir probe arrays; (v) study of long-distance toroidal correlation using data from different electrical probes and the HIBD; and (vi) Cross-correlation analysis of MHD fluctuations using ISTTOK diagnostics, with special emphasises on magnetic probe, tomography and heavy ion beam probe data.; (vii) Data analysis from the Joint Experiment 2007 and participation in JE-2008[4].

3. PARTICIPATION IN THE COLLECTIVE USE OF THE JET FACILITIES BY THE EFDA ASSOCIATES[5],[6],[7]

This project will include activities in the areas of operation, scientific exploitation and performance enhancements.

3.1. Operation

Two members of our staff will have JOC positions. One will work in the LIDAR and Microwave Diagnostics Group, being his activity mainly focussed on: (i) Operation and maintenance of the KG3, KG8b reflectometry diagnostics; (ii) Data validation and analysis of the reflectometry systems and KK3 (ECE) diagnostic; and (iii) Collaboration in the upgrade of the X-mode swept frequency KG8a reflectometer. The other will work in the Plasma Operation Team, in the planning of the experiments and as Session Leader during the campaigns.

3.2. Scientific exploitation

IST will proceed with an important contribution to the JET scientific exploitation mainly through an active participation in the experimental campaigns and in analysis/interpretation and modelling of the experimental data, with particular emphasis in the integration of transport and MHD codes.

3.2.1. Experimental campaigns and related physics studies

IST plans the participation of twenty members of its staff in the experimental campaigns C20/C25 (four of them as session leaders). The work will be mainly focussed on developments and physics studies related with Task Forces M, S1, T, D, E and H.

The following main activities are foreseen in Task Force M:(i) Participation in experiments to compare fast ion losses from core Alfven eigenmodes in several operating scenarios; (ii) Study of sawtooth characterization at high ICRH power; (iii) Further studies of the sawteeth instability, and analysis of the interplay between different instabilities:sawteeth, fushbones and TAEs interacting with the same population of fast ions; (iv) Study of the changes in the fast particles distribution caused by fishbone bursts and TAEs, using the Lost Alfa Particles diagnostics;identification of the unperturbed orbits of lost ions (i.e. the orbits before they interact with MHD modes) using numerical codes; (v) Study of ICRH-accelerated He3 redistribution by Fishbones; use of numerical codes (MISHKA and CASTOR-K) to identify the particles in resonance with these modes; (vi) Study of ICHR-driven fast ion effects on sawteeth when the heating resonance is located near the q = 1 surface;(vii) Participation in the Momentum Brakingexperiments, to perform a parametric scan on plasma collisionality (both the collisional and collisionless regimes) where the neoclassical toroidal viscous force is shown to play a role in the toroidal momentum braking; (viii) Neoclassical tearing mode studies, to probe the intrinsic stabilizing/destabilizing character of the ion polarisation current on the stability of NTMs; (ix) Development of improved mode analysis and correlation analysis techniques, namely using the Wigner distribution for MHD mode analysis, and for correlation/coherence calculations with possible application to correlation reflectometry.

Concerning Task Force S1 the following tasks are foreseen: (i) Participation in experiments on pedestal identity and * scan (with AUG and DIII-D), with emphasis on the study of pedestal characterization and MHD stability at low collisionalities at different values of the toroidal field ripple; (ii) Participation in experiments on Hot-ion H-modes and in the use of the Pellet Pacing technique for control of ELMs in these high temperature pedestal plasmas.

Concerning Task Force T the following tasks will be performed: (i) Preparation of integrated transport and MHD tools for modelling of experiments planned to study plasmas with high temperatures pedestals, using MISHKA and CASTOR for the edge MHD stability and JETTO for transport modelling; (ii) Continuation of modelling of Quiescent H-mode (QHM)discharges, to understand the differences between the edge stability in JET and the QHMs in ASDEX Upgrade and DIII-D; (iii) Simulations of impurity transport using the JETTO/SANCO transport model (with Bohm/GyroBohm transport) , including the effects of different heating schemes, for comparison with experimental results and theoretical models like the one included in GLF23 ; (iv) Benchmark of the results from Argon using JETTO/SANCO code with and without the bundled states from the new ADAS database in order to use this reference for the Tungsten; (v) Continuation of transport modelling for ITER scenarios, including the effects of the Helium ash accumulation in the plasma core on the fusion performance; (vi) Modelling of ITB behaviour in advanced tokamak scenarios using JETTO and trying to match the results with GLF23; and (vii) Support to the analysis and transport modelling of experiments on momentum transport using perturbative methods;

The following activities in Task Force D are planned: (i) Test/Calibration of the X-mode broadband system (KG8a) with hardware improvements aiming to minimize spurious effects on the density profiles and development of data interface for the new data acquisition system; experiments with the diagnostic aiming to obtain edge density profiles in a wide range of plasma scenarios. (ii) Possible operation (by the end 2008) of the advanced system (KG10) in fast sweeping time (10 s); (iii) Scientific exploitation of data from KG8a and KG8b (correlation) systems:characterization of Alfvén cascades, namely radial localization of different types of AE modes; study of fishbone and bi-directional TAEs based on turbulence analysis; analysis of the correlation length of turbulence and turbulence changes due to ITB formation; investigation of density fluctuations at both high- and low- magnetic field sides;study of MHD and turbulence signatures of transient phenomena namely ELM and sawtooth instability; (iv) MSE data processing : Installation in the real-time Network (if approved) of the novel real-time APD amplitude estimation technique, based on Kalman filtering; and integration of the real-time magnetic pitch angle estimates in a real-time plasma equilibrium reconstruction code;(v) collaboration in the exploitation of the high resolution Thomson scattering diagnostic.

Regarding Task Force E it is envisaged: (i) Detailed characterization of the SOL in ICRH heated plasmas with the reciprocating probe head;(ii) Analysis of the data from the boundary plasma to characterize the properties of the intermittent events and to obtain quantitative information on the size, duration and velocity associated with plasma structures for different confinement regimes.

Finally, in Task Force H it is expected the participation in experiments on intrinsic rotation in Ohmic and ICRF heated plasmas without and with enhanced toroidal field ripple.

3.2.2 Integration of transport and MHD codes

The following activities are foreseen: (i) Further improvement of the edge stability physics in JETTO, in particular to continue to benchmark the stability criteria for peeling modes against MISHKA and CASTOR stability, for a wide range of edge pressure and current density profiles; (ii) Preparation of a series of standard tests for sawtooth and ELM models in JETTO, which should be run before an official release of JAMS upgrade;(iii) Adapting the graphical interface codes EPROC_GUI and JAMS-UTC in order to use the new ADAS database for the super charge states of Tungsten and Argon.

3.3. Enhancements

Concerning the JET-EP project, the Association EURATOM/IST will be in charge of the following contracts:

  • Enhancement of the sweeping reflectometer (KG8a);
  • Data acquisition for the neutron camera diagnostics enhancements (DNGG);
  • Data acquisition for the gamma ray spectroscopy (GRS);
  • ATCA hardware platform for the Plasma Control Upgrade project (PCU-VS);
  • Development of a Digital Link for the Vertical Stabilization controller (PCU2-VS);
  • Real-Time Measurement & Control Diagnostics & Infrastructure,

and will maintain an engineer in the Diagnostics Engineering Team.

3.3.1. Enhancement of the sweeping reflectometer

The following milestones are foreseen (in collaboration with CEA, the detailed splitting of tasks depending on JET decision): enhancement of the KG8a reflectometer into a multi band system (KG10); this advanced swept system will include three frequency bands and X mode operation in fast sweeping time (10 s), compatible with long transmission lines;

3.3.2. Data acquisition for the neutron camera diagnostics and for the gamma ray spectroscopy

The following tasks will be performed: (i) implementation of an improved prototype of a 8-channel transient recorder board with 400 MSPS, 14-bit resolution; (ii) Implementation of the codes for the acquisition boards (final FPGA code and FireSignal drivers); (iii) Production of the required boards,

assembling and test of the a 24-channel@250MSPS system for DNGG and 4-channels@800MSPS for GRS; (iv) Implementation and simulation of the real-time pulse analysis algorithms for PHA, PSD, pile-up detection/recover/rejection and for PMT correction, as well as its comparison with previous systems; (v) Preliminary tests of the real-time pulse analysis algorithms on the DNGG diagnostic; (vi) Tests of the full data acquisition system in conjunction with the PMT on an accelerator facility in Romenia; (vii) Implementation and test of the FireSignal to CODAS interface and (viii) commissioning at JET.

IST also provides the Project Leader for the data acquisition for the neutron camera diagnostics project.

3.3.3. ATCA hardware platform for the Plasma Control Upgrade

The following tasks will be performed: (i) Production and test of the complete control system hardware which will provide 192 ADC channels sampling at 2 MSPS@18-bit (1 kV galvanic isolation), 24 channel DAC and 48 digital I/O channels; (ii) Development of the FPGA codes including the PCIe interface, ADC interface, DDR2 memory controller and decimation IIR filters; (iii) Development and test of codes for the host computer PCIe device drivers, hardware/data acquisition test program and multiprocessor support; (iv) Implementation and test (latency and jitter measurements with heavy-load processing, reliability of operation over several-day without rebooting and ability of remote diagnose of software faults) of an RTAI-LINUX real-time operating system platform including the multi-platform libraries BaseLib2 and MARTe; (v) Test system performance including noise, cross-talk and linearity, through the comparison with the existing KC1/KC1D/KC1E systems and (vi) Integration with CODAS and commissioning at JET.

3.3.4. Digital Link for the Vertical Stabilization controller

The following tasks will be performed: (i) Specification of the Digital Link hardware and communications protocol (T3P); (ii) Implementation of a test-bench unit and (iii) implementation of a specification/manufacturing package for the Vertical Stabilization power supply designers.

3.3.5. Real-Time Measurement & Control Diagnostics & Infrastructure

This project will continue to expand the JET real-time diagnostics and control capabilities required to fulfill the programmed objectives of JET in the proposed FP7 phase of operation dedicated to the preparation of ITER. The following subtasks are still being developed: (i) Improvement of the real-time measurement capabilities of FIR Interferometry (KG1); (ii) Improvement of the real-time measurement capabilities of some of the Neutron Diagnostics (Total Neutron rate KN1, Hard X-ray rate KH1, 14 MeV neutron rate-KM7); (iii) Expansion of the real-time JET Network Infrastructure to accommodate the extra real-time Diagnostics required for FP7 either by exploiting recent network technologies or by extending existing ATM, including the development and implementation of a Real-Time Network prototype.

IST will also provide the Project Leader.

4. PARTICIPATION IN THE ASDEX-UPGRADE PROGRAMME[8],[9],[10]

This project has two research lines: microwave reflectometry; plasma physics studies on transport, MHD and turbulence.

4.1 Microwave reflectometry

This research line includes activities on hardware developments, data processing and modelling, diagnostic developments, control and data acquisition.

The following activities related with hardware developments will be carried out: (i) Design of a new FM-CW broadband system at the Low Field Side with a bi-static configuration including: support to the implementation by IPP of the new system at a location away from the EC beam to allow operation during ECRH experiments; design and prototype multi-access bi-static antennas, waveguide transmission lines and systems for profile reflectometers; development of advanced electronics for emission and detection sections of the diagnostic; (ii) study of an FM-CW system with inboard launch (HFS) to access the plasma core with lower cutoff – X mode.

On data processing for density profile analysis it is planned: (i) testing of the algorithms developed for the automatic analysis of edge pedestal characteristics and integration of resulting data in the level-1 AUG shotfile; (ii) integration of burst mode profiles providing data with higher quality in level-2 density profiles on a routine basis; (iii) assessment/development of a robust ELM detection technique in order to prevent data measured during ELMS from corrupting the reflectometry burst mode profiles; (iv) investigation of sensitivity of density profiles to initialization and study of density profile behavior in edge gradient and SOL regions; (v) study of a new density profile inversion technique using algorithms based on Bayesian analysis (depending on the availability of the expert Dr. Rainer Fisher, from IPP).