This paper documents the public release PR08 of the International Tokamak Physics Activity (ITPA) profile database, which should be of particular interest to the magnetic confinement fusion community. Data from a wide variety of interesting discharges from many of the world's leading tokamak experiments are now made available in PR08, which also includes predictive simulations of an initial set of operating scenarios for ITER. In this paper we describe the discharges that have been included and the tools that are available to the reader who is interested in accessing and working with the data. Most discharge descriptions refer to more detailed previous publications. In addition, we review physics analyses that have already made use of the profile database discharges. Public access to PR08 data is unconditional, but this paper should be cited by any publication that makes use of PR08 data.

The JET experimental campaign has focused on studies in support of the ITER physics basis. An overview of the results obtained is given for the reference ELMy H mode and advanced scenarios, which in JET are based on internal transport barriers. JET studies for ELMy H mode have been instrumental in the definition of ITER FEAT. Positive elongation and current scaling in the ITER scaling law have been confirmed, but the observed density scaling fits a two term (core and edge) model better. Significant progress in neoclassical tearing mode limits has been made showing that ITER operation with q(95) around 3.3 seems to be optimized. Effective helium pumping and divertor enrichment is found to be well within ITER requirements. Target asymmetries and hydrogen isotope retention are well simulated by modelling codes taking into account drift flows in the scrape-off plasmas. Striking improvements in fuelling effectiveness have been made with the new high field pellet launch facility. Good progress has been made on scenarios for achieving good confinement at high densities, both with radiation improved modes and with high field side pellets. Significant development of advanced scenarios, in view of their application to ITER, has been achieved. Progress towards integrated advanced scenarios is well developed with edge pressure control (impurity radiation). An access domain has been explored showing, in particular, that the power threshold increases with magnetic field but can be significantly reduced when lower hybrid current drive is used to produce target plasmas with negative shear. The role of ion pressure peaking on MHD has been well documented. Lack of sufficient additional heating power and interaction with the septum at high beta prevents assessment of the beta limits (steady plasmas achieved with beta (N) up to 2.6). Plasmas with a non-inductive current (I(NI)/I(p) = 60%), well aligned with the plasma current, high beta and good confinement have also been obtained.

Equilibrium reconstruction is the essential tool for determining the field configuration and current density in a tokamak discharge. Most equilibrium reconstruction codes use the Grad-Shafranov equation, which relies on the assumption of isotropic pressure. This property is often violated for additionally heated discharges. We report on the implementation of an anisotropic pressure model for the equilibrium reconstruction code EFIT. The anisotropy model exhibits more degrees of freedom and makes the reconstruction more sensitive to experimental errors. We use a regularization technique (L-curve) that attempts to generate an optimal equilibrium. The algorithm is applied to selected high-performance discharges of the tokamaks JET and Tore Supra.

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.

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.

Plasmas with the energy confinement time enhanced by a factor 1.4 to 2.1 over the ITER93H-P H-mode scaling expression have been obtained in 3 different H-mode regimes (excluding pellet injection) in JET. The phase of enhanced confinement has strong similarities with the VH-mode observed in DIII-D in all 3 cases. The JET data clearly show VH-mode confinement increasing with plasma current and degrading with loss power.

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.

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

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.