Renewables and energy efficiency measures represent an important way to improve the security of energy supply and to bring to Europe the other important advantages of environmental benefits together with technological development. The EU has put in place a new regulatory framework, with a view to accelerating the growth of EU markets for renewable electricity. In this context, an important instrument is the Directive on electricity produced from renewable energy sources. The future development of photovoltaics is supported through the EU Framework Programme, for both research and demonstration activities and through the Intelligent Energy - Europe Programme for non-technological actions. Research focuses on the next generation of PV technologies while the aim of the demonstration activities is to accelerate the market penetration of more cost-effective PV technologies. To stimulate public-private partnerships between the research community, industry and policy makers with the aim of mobilising greater research and innovation effort the Commission has supported the launching of a Technology Platform on Photovoltaics. To accelerate the development, demonstration and market introduction of a new generation of PV systems, the European Commission is combining an intense legislative initiative with a strong research and demonstration effort.

In view of the EU's policy commitments to expanding the contribution of renewable energy sources (notably renewable electricity) to final EU energy consumption and to supporting is use in third countries, the future development of PV in the European Union will be supported through both research and demonstration actions. Research will focus on the next generation of PV technologies, including thin film PV, processing and automated manufacturing, cost reductions for components and systems as well as research for innovative applications of PV in the built environment. The aim of the demonstration activities will be to accelerate the market penetration of more cost-effective PV technologies. The priorities are to demonstrate innovative production concepts for high efficiency modules (including integrated inverter solutions), and to transfer a new generation of PV products to industrial scale, as well as to promote the markets for building integration and autonomous generation systems. Special attention will be given to facilitating access to new PV technologies for developing countries.

The vertical position of the JET plasma is normally unstable and feedback stabilisation is therefore needed. A new power amplifier (fast radial field amplifier-FRFA) based on GTO inverters has been procured to cope with configurations characterized by plasma having a high degree of vertical instability, beyond the stabilising capability of the phase controlled thyristor power converter used so far. The new power amplifier is composed of four identical subunits which can be connected in two different configurations to achieve output voltages up to 10 kV (at 2.5 kA) and output currents up to 5 kA (at 5 kV). The amplifier is characterised by a peak output power of 25 MW and by switching frequencies of the individual GTOs of 1 kHz. The series connection of more inverters allows more voltage levels (up to nine) to be made available on the load. The paper presents the results of the extensive series of tests on a dummy load performed on the amplifier both at factory, where a complete subunit was assembled, and at the JET sites. The tests included the achievement of the full performances and the assessment of the correct operation of all the required control modes

Recent experiments in D-T plasmas on the JET and TFTR tokamaks have evaluated a wide range of ITER relevant ion cyclotron heating scenarios. Absorption of fast waves at the second-harmonic tritium resonance has provided bulk ion heating in TFTR supershots and electron heating in JET H-mode discharges. In JET, deuterium minority heating has generated 1.7 MW of fusion power with 6 MW of radio frequency power giving a record steady-state Q-value of 0.22. Strong bulk ion heating has been achieved with He-3 minority heating with central ion temperatures up to 13 keV being produced in H-modes with a density of 3.6 x 10(19) m(-3) Hydrogen, deuterium and He-3 minority heating methods have produced plasmas with normalized confinement times greater than or equal to that required by ITER for ignition. These H-modes are characterized by small-amplitude, high-frequency ELMs, each of which transports less than 1.5% of the plasma energy content to the limiters. The heavy minority scheme of tritium in a deuterium plasma has been demonstrated both as a heating scheme and a generator of suprathermal neutrons. On TFTR mode conversion to an ion Bernstein wave has achieved central bulk ion heating in supershots with target ion temperatures greater than 20 keV.

Two pumped diverters have been installed and tested in JET under ITER relevant conditions. A closed divertor is found to increase the particle and impurity exhaust rate in agreement with code modelling. Excellent power handling is demonstrated, allowing high current discharges with record stored energy (15 MJ) and quasi-steady-state discharges with high fusion triple product (4 x 10(20) m(-3) s keV). The ITERH93-P confinement scaling law is confirmed over abroad range and a more favourable beta scaling is found. No hysteresis is found in the II-mode power threshold. A data base of highly radiating discharges including impurity seeding describes the relationship between radiated power, impurity concentration and density. First results of high performance with optimised magnetic shear are presented. Strong internal confinement barriers develop despite the relatively small input of toroidal momentum and particle fuelling from ICRH and NBI.

JET is equipped with a set of in-vessel Saddle Coils which have been used for experiments on the stabilisation of tearing modes by magnetic feedback, for studies on the error fields modes, and for the excitation of Alfven Eigenmodes. The system comprising the coils, the power supplies and the respective controllers, has been extensively operated since 1994. The strong interactions with plasma and the arcing during plasma vertically displaced disruptions have produced currents through the upper coils in excess of their mechanical capabilities.

All major JET systems have been fully commissioned for D-T and the DTE1 series of experiments has started with the D-T fuel mixture and operating conditions foreseen for ITER. In the area of ITER physics, significant results have been produced in both D-D and D-T. In D-D, the LH threshold power database has been extended, the bounds on edge-electron temperature and density in ELMy H-modes have been defined and the advantages of Types I and III ELMy discharges have been compared. In D-T plasmas, the isotope effect on H-mode threshold power and transport has been determined so that a more accurate assessment can be made of the ignition margin and heating requirements for ITER. Trace tritium experiments have provided first particle transport measurements and an assessment of the ITER reference ion-cyclotron resonance-frequency heating scenarios has been started, In the area of fusion performance, record D-D neutron yields have been obtained by controlling the plasma and current profiles in hot ion ELM-free H-modes and optimized shear modes. In D-T, internal transport barriers have been readily established in optimized shear discharges and Alfven eigenmodes have been observed.

This paper presents an overview of results of the 1994/95 experimental campaign on JET with the new pumped divertor and draws implications for ITER in the areas of detached and radiative divertor plasmas, the use of beryllium as a divertor target the material, the confinement properties of discharges with the same dimensionless parameters (except for the dimensionless Larmor radius) as ITER and the effect of varying the toroidal magnetic field ripple in the ITER relevant range. Discharges with high fusion performance at high current, in steady-state with ELMs and in the ELM-free hot-ion H-mode, are also reported. Limits to operations are discussed and projections to D-T performance are made.

The JET neutral beam injection system has proved to be both effective and reliable as a plasma heating device. The ion heating and plasma fuelling characteristics of the system are ideally suited to the production of high fusion performance plasmas while the flexibility in the choice of beam species (H, D, T, 3He or 4He) and the ability to inject into almost any JET plasma configuration allows a wide variety of related physics experiments to be carried out. The capability to inject (for the first time) tritium beams was essential to the successful execution of the first tritium experiments in which 1.7 MW of power from DT fusion reactions was generated.

JET was extensively modified in the 1992/93 shutdown. The new pumped divertor and many new systems were brought into operation early in 1994. Operations have progressed to 4 MA plasma current and, with substantial additional heating, H-mode confinement results confirm the expected scaling. The high power handling capability of the pumped divertor with sweeping is estimated at 20 MW for 20 s. H-mode plasmas have large Type I ELMs. With lower hybrid heating alone, 2 MA full current drive has been achieved with good efficiency, and with ICRF power, effective heating and direct electron heating have been demonstrated.

A fast power amplifier has been designed and built to control the plasma vertical position even with the more demanding configurations that will be produced in JET in the future. Switched inverters with gate turn-off thyristors, allow a fast response time (200 μs) to be reached at high performance (10 kV, 2.5 kA); a new concept of control, based on a multilevel hysteresis cycle improves the performance compared with pulse width modulation. The equipment has been designed and built; factory tests are in progress.

Describes a series of experiments in the Joint European Torus (JET), culminating in the first tokamak discharges in deuterium-tritium fuelled mixture. The experiments were undertaken within limits imposed by restrictions on vessel activation and tritium usage. The objectives were: (i) to produce more than one megawatt of fusion power in a controlled way; (ii) to validate transport codes and provide a basis for accurately predicting the performance of deuterium-tritium plasmas from measurements made in deuterium plasmas; (iii) to determine tritium retention in the torus systems and to establish the effectiveness of discharge cleaning techniques for tritium removal; (iv) to demonstrate the technology related to tritium usage; and (v) to establish safe procedures for handling tritium in compliance with the regulatory requirements. A single-null X-point magnetic configuration, diverted onto the upper carbon target, with reversed toroidal magnetic field was chosen. Deuterium plasmas were heated by high power, long duration deuterium neutral beams from fourteen sources and fuelled also by up to two neutral beam sources injecting tritium. The results from three of these high performance hot ion H-mode discharges are described: a high performance pure deuterium discharge; a deuterium-tritium discharge with a 1% mixture of tritium fed to one neutral beam source; and a deuterium-tritium discharge with 100% tritium fed to two neutral beam sources. The TRANSP code was used to check the internal consistency of the measured data and to determine the origin of the measured neutron fluxes. In the best deuterium-tritium discharge, the tritium concentration was about 11% at the time of peak performance, when the total neutron emission rate was 6.0 × 1017 neutrons/s. The integrated total neutron yield over the high power phase, which lasted about 2 s, was 7.2 × 1017 neutrons, with an accuracy of ±7%. The actual fusion amplification factor, QDT was about 0.15

The first tokamak discharges with deuterium-tritium mixtures have been carried out in the Joint European Torus (JET). The main objectives were to produce more than IMW of fusion power in a controlled way, to determine tritium retention in torus systems and to establish effective means of tritium removal. The experiments were undertaken within limits imposed by restrictions on vessel activation and tritium usage. Deuterium plasmas were heated by high power deuterium neutral beams from fourteen sources and fuelled by two neural beam sources injecting tritium. In the best (D-T discharge), the tritium concentration was about 11% at peak performance, when total neutron emission rate was 6.0*1017 s-1, with 1.7 MW of fusion power. The fusion amplification factor QDT was 0.15. With optimum tritium concentration, this pulse would have produced a fusion power approximately=5 MW and nominal QDT=0.46. The same extrapolation for the best pure deuterium discharge gives about 11 MW and a nominal QDT=1.14. Techniques for introducing, tracking, monitoring and recovering tritium were highly effective.

In 1990 JET operated with a number of technical improvements which led to advances in performance and permitted the carrying out of experiments specifically aimed at improving physics understanding of selected topics relevant to the "NEXT STEP". The new facilities include beryllium antenna screens, a prototype lower hybrid current drive system, and modification of the NI system to enable the injection of He-3 and He-4. Continued investigation of the hot-ion H-mode produced a value of n(D)(0)tau-E(T)(i)(0) = 9 x 10(20)m-3s keV, which is near conditions required for Q(DT) = 1, while a new peaked density profile H-mode was developed with only slightly lower performance. Progress towards steady state operation has been made by achieving ELMy H-modes under certain operating conditions, while maintaining good tau-E values. Experimental simulation of He ash transport indicates effective removal of alpha-particles from the plasma core for both L and H mode plasmas. Detailed analyses of particle and energy transport have helped establish a firmer link between particle and energy transport, and have suggested a connection between reduced energy transport and reversed shear. Numerical and analytic studies of divertor physics carried out for the pumped divertor phase of JET have helped clarify the key parameters governing impurity retention, and an intensive model validation effort has begun. Experimental simulation of alpha-particle effects with beta-fast up to 8% have shown that the slowing down processes are classical, and have given no evidence of deleterious collective effects.

During its 1990 operation, 2 large RF systems were available on JET. The ion cyclotron resonance heating (ICRH) system was equipped with new beryllium screens and with feedback matching systems. Specific impurities generated by ICRH were reduced to negligible levels even in the most stringent H-mode conditions. A maximum power of 22 MW was coupled to L-mode plasmas. A new high confinement mode was discovered. Experiments were performed with the prototype launcher of the lower hybrid current drive (LHCD) systems with coupled power up to 1.6 MW with current drive efficiencies up to R ICD/P=0.4*1020 m-2 A/W. The authors present the first observations of the synergistic acceleration of fast electrons by transit time magnetic pumping (TTMP) (from ICRH) and electron Landau damping (ELD) (from LHCD). The synergism generates TTMP current drive even without phasing the ICRH antennae.