M. Medrano

Overview of TJ-II flexible heliac results

The TJ-II is a four period, low magnetic shear stellarator, with high degree of configuration flexibility (rotational transform from 0.9 to 2.5) which has been operating in Madrid since 1998 (R = 1.5 m, a 0.22 m, B0 = 1T , PECRH600 kW, PNBI3 MW under installation). This paper reviews the main technical aspects of the TJ-II heliac as well as the principal physics results obtained in the most recent TJ-II experimental campaign carried out in 2000.

TJ-II neutral beam injectors control and data acquisition system

Abstract The Control and Data Acquisition System for the Neutral Beam Injectors of TJ-II are described in this paper. The DAQ and Control architecture is based on a distributed system including VME-OS9 real-time computers and personal computers (PCs) with Linux and Windows NT. One OS9-VME local computer located near each injector performs the timing, local signal processing, signal interlock, and operation of the injector mechanical and electrical components. A main OS9-VME interfaces and controls some peripheral systems, such as the high voltage power supplies, water cooling, safety and protection systems. Control is performed from the OS9-VME machines, in which the software elements are basically C/C++ programs performing real time processing and a web server enabling access to the HTML pages acting as user graphic interface.

Construction, commissioning and first results of the Spanish Stellarator TJ-II

The Spanish Stellarator TJ-II is a highly flexible medium-size fusion device of the heliac-type constructed at CIEMAT in Madrid, Spain from 1991 to 1997. The magnetic field mapping at low magnetic fields were conducted through in December 1996 and January 1997 with excellent results. From January 1997 up to now the commissioning of the device up to the design values is being done together with the assembly of the basic diagnostic equipment and the auxiliary heating systems. The first plasma is expected still for October 1997.

TECHNICAL ASPECTS AND STATUS OF THE SPANISH STELLARATOR TJ-II

Abstract TJ-II is a medium-size stellarator of the heliac-type being under construction in Madrid, Spain. The project was granted EURATOM preferential support phase II in November 89 and is expected to start operation in 95. This device allows the exploration of a wide range of magnetic configurations. The rotational transform can be varied from 0.9 to 2.5. Shear variation is possible up to 10%. Theory predicts maximum beta values as high as 6%. The average major plasma radius is 1.5 m. The minor dimensions of the bean-shaped plasma are approximately 0.4 m by 0.2 m. Toroidal field: 1T. Pulse length: 0.2 s to 1 s. Pulse break: 5 min. Auxiliary heating: 400 kW ECRH at 53.2 GHz in stage I; 2 MW NBI will be added in stage II. In stage III 4 MW NBI heating is planned to be applied. The paper gives an overview on the technical features of the experiment, describes the main aspects of the recent engineering work and presents the status of the device.

Transport Properties in the TJ‐II Flexible Heliac

TJ‐II flexibility is exploited to perform an investigation on the transport properties of this device. Rotational transform can be varied in a wide range, which allows one to introduce low order rationals and to study their effect on transport. On the other hand, confinement properties can be studied at very different rotational transform values and for different values of magnetic shear: Experiments on influence of the magnetic shear on confinement are reported. Plasma potential profiles have been recently measured in some configurations up to the plasma core with the Heavy Ion Beam Probe (HIBP) diagnostic and the electric field values measured in low‐density plasmas are consistent with neoclassical calculations near the plasma core. Plasma edge turbulent transport has been studied in configurations that are marginally stable due to decreased magnetic well. Results show a dynamical coupling between gradients and turbulent transport.

Vandellos: A European site for ITER

On April 17/sup th/ 2002, Spanish Government formally offered the Vandellos site as a possible European ITER site. In this work main technical site specific characteristics of the site are compared with generic requirements. It is shown that Vandellos site offers a number of technical advantages over the reference design mainly in relation with the geotechnical and seismic assumptions as well as in relation with heat sink, electrical supply and heavy transport topics.

Integration and user interface using WWW technologies for the control and DAQ of the neutral beam injectors of the TJ-II Heliac

This paper describes the software architecture being implemented in the Control and Data Acquisition System for the Neutral Beam Injectors of the TJ-II Heliac at CIEMAT (Madrid, SPAIN), devoted to fusion plasma studies. Also a brief review is given of the hardware components. The main issue of this paper is the assessment of the use of the World Wide Web concept and tools for the integration of the whole system and its user graphic interface. Previous experience with the user interface of the TJ-II timing system and gas puffing programming were fully satisfactory. Control is performed from OS9-VME machines, in which the software elements are basically C/C++ programs performing real time processing and a web server enabling access to the html pages providing control menus or panels. A console of the system could be any kind of computer with a web browser connected to the NBI ethernet LAN. Access to panels or menus of the whole system is obtained by just linking the corresponding html page addresses.