This paper presents an overview of the results obtained during the Joint Experiments organized in the framework of the IAEA Coordinated Research Project on ‘Joint Research Using Small Tokamaks’ that have been carried out on the tokamaks CASTOR at IPP Prague, Czech Republic (2005), T-10 at RRC ‘Kurchatov Institute’, Moscow, Russia (2006), and the most recent one at ISTTOK at IST, Lisbon, Portugal, in 2007. Experimental programmes were aimed at diagnosing and characterizing the core and the edge plasma turbulence in a tokamak in order to investigate correlations between the occurrence of transport barriers, improved confinement, electric fields and electrostatic turbulence using advanced diagnostics with high spatial and temporal resolution. On CASTOR and ISTTOK, electric fields were generated by biasing an electrode inserted into the edge plasma and an improvement of the global particle confinement induced by the electrode positive biasing has been observed. Geodesic acoustic modes were studied using heavy ion beam diagnostics on T-10 and ISTTOK and correlation reflectometry on T-10. ISTTOK is equipped with a gallium jet injector and the technical feasibility of gallium jets interacting with plasmas has been investigated in pulsed and ac operation. The first Joint Experiments have clearly demonstrated that small tokamaks are suitable for broad international cooperation to conduct dedicated joint research programmes. Other activities within the IAEA Coordinated Research Project on Joint Research Using Small Tokamaks are also overviewed.

Small tokamaks may significantly contribute to the better understanding of phenomena in a wide range of fields such as plasma confiement and energy transport; plasma stability in different magnetic configurations; plasma turbulence and its impact on local and global plasma parameters; processes at the plasma edge and plasma‐wall interaction; scenarios of additional heating and non‐inductive current drive; new methods of plasma profile and parameter control; development of novel plasma diagnostics; benchmarking of new numerical codes and so on. Furthermore, due to the compactness, flexibility, low operation costs and high skill of their personnel small tokamaks are very convenient to develop and test new materials and technologies. Small tokamaks are suitable and important for broad international cooperation, providing the necessary environment and manpower to conduct dedicated joint research programmes. In addition, the experimental work on small tokamaks is very appropriate for the education of students,...

The 1st Joint (Host Laboratory) Experiment on 'joint research using small tokamaks' was carried out using the IPP Prague experimental facility 'CASTOR tokamak'. The main experimental programme was aimed at characterizing the edge plasma in a tokamak by using different advanced diagnostic techniques. It is widely recognized that characterization of phenomena occurring at the plasma edge is essential for understanding the plasma confinement in a tokamak. The edge plasma in small and large scale experiments has many similar features, and the results obtained through detailed measurements in a small flexible device such as CASTOR are in many aspects still relevant to those in large tokamaks. Therefore, it is expected that the results of this joint experiment will have general validity. The radial and poloidal structure of electrostatic turbulence was characterized. The effects of edge biasing were analysed. Radiation fluctuations and profile measurements were performed using fast bolometry. Plasma position measurements were performed using novel Hall sensors.

The 1 Joint (Host Laboratory) Experiment on “Joint Research Using Small Tokamaks” has been carried out using the IPP Prague experimental facility "CASTOR Tokamak". The main experimental programme was aimed to characterize the edge plasma in a tokamak by using different advanced diagnostic techniques. It is widely recognized that characterization of phenomena occurring at the plasma edge is essential for understanding of the plasma confinement in a tokamak. The edge plasma in small and large scale experiments has many similar features, and the results obtained through detailed measurements in a small flexible device such as CASTOR are in many aspects still relevant to those in large tokamaks. Therefore, it is expected that results of this joint experiment will have a general validity.

A coupled numerical model of the atmospheric thermo-hydrodynamics and pollutant photochemical transport is described. This model can be used to study the complex relationships between the chemical and thermo-hydrodynamic processes in the atmosphere of urban areas with an emphasis on photochemical ozone formation. Preliminary numerical results of ozone and other key chemical atmospheric pollutant concentrations and distribution across the Houston-Galveston-Brazoria area using virtual emission data from area and mobile sources are presented.

The objective of this study, funded by DGXI (now DGEnv (Directorate General Environment) of the European Commission, was to evaluate the impact of radiological contamination in the environment, which has resulted from the operations at the nuclear establishments at Krasnoyarsk-26, and to determine whether any remedial actions are required. Environmental data has been obtained for a wide range of environmental media and for a number of years covering the period before and after the closure of the single pass reactors at Krasnoyarsk-26. These media include air (aerosols and deposition), water, sediments, soil, floodplain deposits, foodstuffs and vegetation. Information was also obtained on demography, meteorology and the general geological, geographical and hydrological characteristics of the regions. A GIS (Geographical Information System) system was established to contain all of this data and to display a number of themes. The sampling and analytical methodologies were evaluated and the data were examined to determine any trends with time or distance from the contamination sources. The data were compared with other global data available in the open literature. A methodology for the radiological assessment of the contamination was established and the calculations performed. The results of the radiological assessments showed that the most significant exposures resulted from the occupancy and use of the contaminated floodplains and from the potential exposure to hot particles. Doses of several millisieverts a year could result from some of the most contaminated sites and of tens to hundreds of millisieverts from hot particles. Criteria for remedial action and a number of remediation options were evaluated.

The problem of constructing (2+1)-dimensional tachyonless models of relativistic particles with an action depending on the world-trajectory curvature and torsion, is investigated. A special class of models, described by a maximal symmetric action and comprising only spin internal degrees of freedom, is found. Examples of systems from the special class are given, whose classical and quantum spectra contain only massive states.