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Problems of plasma-wall interaction in TOKAMAKS
Vacuum~volume 33/number 1/2/pages 129 to 13411983
0042-207X/83/010129-06S03.00/0 1983 Pergamon Press Ltd
Printed in Great Britain
Abstracts Vl Problems of plasma-wall interaction in TOKAMAKS E. Hints., lnst f Plasmaphysik, KFA Jiilich, FRG For the generation and confinement of a thermonuclear plasma, the interaction of the plasma with the surrounding walls is of critical importance. The consequences of this interaction are: 1. Erosion and damage of the first wall; 2. Degassing of contaminants out of the first wall; 3. Recycling of hydrogen hitting the first wall The understanding of the basic process of the plasma-wall interaction is not satisfactory at presem. It is not yet possible to predict the size of the expected effects or to compare the si~mificance of the most important processes. The reason for this unsatisfactory situation is: ---the non uniform distribution of the particle and energy fluxes impinging on the wall ---the appearance of synergetic effects ---complex chemical processes at the surface. Mastering the plasma-wall interaction requires not only a sufficient control of the behaviour of the plasma boundary-possibly using divertors---but also a proper choice of the parameters of the wall, e.& material, shape and temperature. To achieve this proper choice appropriate diagnostic methods for the wall surface and for the plasma close to the wall are mandatory. V2 Research on atomic collision processes and its importance for future energy sources
D Ber~nyi, Institute of Nuclear Research of the Hungarian Academy of Sciences (A TOM KI), Debrecen, Hungary First the energy demands and resources of society are briefly surveyed, including one of the most important sources: controlled nuclear fusion. Then the importance of atomic collision data for solving the different problems in the realization of the controlled fusion processes are outlined. Finally some results obtained in this field in ATOMKI (Debrecen), Hungary are summarized. V3 Limiters for TOKAMAICS of the next (the JET-) generation
order to withstand the high energy fluxes large area iimiters have to be applied. Factors that influence the energy transfer between plasma and limiter will be sketched. The selection of limiter material is discussed with regard to impurity production and resistance to large thermal loads. The design of the fimiters for large TOKAMAKS is compared. V4
Appfication of superconductivity in energy research H Haslacher, VM W Ranshofen-Berndorf, Wien, Austria Superconductivity--discovered in 1911--is simply described by the disappearance of the electrical resistance of certain materials in the vicinity of the absolute zero. The first superconductors discovered were pure metals, which are not suitable for high power application because at small magnetic fields (< 0.1 T) a transition to the normal state results. In the 1960s the discovery of the socalled high field superconductors, especially NbTi and Nb3Sn effected an interest in superconductivity for energy research because fields of 8T to 13T--dependent on temperature and current density--are realizeable. Fields of application of superconductors are where high magnetic fields at low energy demand are maintained for long periods of time. Starting points are superconducting laboratory magnets and magnets for high energy physics. Especially in nuclear fusion using magnetic confinement, the application of superconductivity is crucial for a positive energy balance. In practically all fields of energy technology, except fusion, superconductivity is in competition with conventional technologies. Of electric generators, there exist superconducting laboratory and prototype machines only. MHD generators and rotating DC machines using stationary magnetic fields, three-phase ACsynchronous generators with superconducting excitation coils working with rotating fields are of interest for industry world wide. Further applications of superconductivity are in magnetic separation (coal desulfurization), the magnetic suspension railway and in superfast computers using the Josephson effect. V5 Research and development of electronic devices in submicron
H Vernickel, Max-Pianck-lnstitut fdr Plasmaphysik, EURATOM Association, D-8046 Garching, Germany In TOKAMAKS without divertors a large fraction of the heating power ends up at the limiters where therefore plasma-wall interaction is especially severe. Depending on the properties of the boundary plasma and the impurity content of the main plasma between a few per cent and 70% of the heating power has to be taken by the limiter. In the next generation of TOKAMAKS plasma current, energy content of the plasma and energy throughput will be a factor of 5 to 10 larger than at present. In
technology W G6pel, Phys Dept, Montana State University, Bozeman, Montana 59717, USA (on leave of absence from Inst Phys Chemie der Univ, Hannover) The design of very large-scale integrated circuits (VLSI), which is of great technological importance, requires a new generation of instruments and a new array of techniques adequate to give spatial resolution below 1 p. Because of the large wavelength of photons in the visible range, beams of electrons, ions or x-rays 129
0042-207X/83/010129-06S03.00/0 1983 Pergamon Press Ltd
Printed in Great Britain
Abstracts Vl Problems of plasma-wall interaction in TOKAMAKS E. Hints., lnst f Plasmaphysik, KFA Jiilich, FRG For the generation and confinement of a thermonuclear plasma, the interaction of the plasma with the surrounding walls is of critical importance. The consequences of this interaction are: 1. Erosion and damage of the first wall; 2. Degassing of contaminants out of the first wall; 3. Recycling of hydrogen hitting the first wall The understanding of the basic process of the plasma-wall interaction is not satisfactory at presem. It is not yet possible to predict the size of the expected effects or to compare the si~mificance of the most important processes. The reason for this unsatisfactory situation is: ---the non uniform distribution of the particle and energy fluxes impinging on the wall ---the appearance of synergetic effects ---complex chemical processes at the surface. Mastering the plasma-wall interaction requires not only a sufficient control of the behaviour of the plasma boundary-possibly using divertors---but also a proper choice of the parameters of the wall, e.& material, shape and temperature. To achieve this proper choice appropriate diagnostic methods for the wall surface and for the plasma close to the wall are mandatory. V2 Research on atomic collision processes and its importance for future energy sources
D Ber~nyi, Institute of Nuclear Research of the Hungarian Academy of Sciences (A TOM KI), Debrecen, Hungary First the energy demands and resources of society are briefly surveyed, including one of the most important sources: controlled nuclear fusion. Then the importance of atomic collision data for solving the different problems in the realization of the controlled fusion processes are outlined. Finally some results obtained in this field in ATOMKI (Debrecen), Hungary are summarized. V3 Limiters for TOKAMAICS of the next (the JET-) generation
order to withstand the high energy fluxes large area iimiters have to be applied. Factors that influence the energy transfer between plasma and limiter will be sketched. The selection of limiter material is discussed with regard to impurity production and resistance to large thermal loads. The design of the fimiters for large TOKAMAKS is compared. V4
Appfication of superconductivity in energy research H Haslacher, VM W Ranshofen-Berndorf, Wien, Austria Superconductivity--discovered in 1911--is simply described by the disappearance of the electrical resistance of certain materials in the vicinity of the absolute zero. The first superconductors discovered were pure metals, which are not suitable for high power application because at small magnetic fields (< 0.1 T) a transition to the normal state results. In the 1960s the discovery of the socalled high field superconductors, especially NbTi and Nb3Sn effected an interest in superconductivity for energy research because fields of 8T to 13T--dependent on temperature and current density--are realizeable. Fields of application of superconductors are where high magnetic fields at low energy demand are maintained for long periods of time. Starting points are superconducting laboratory magnets and magnets for high energy physics. Especially in nuclear fusion using magnetic confinement, the application of superconductivity is crucial for a positive energy balance. In practically all fields of energy technology, except fusion, superconductivity is in competition with conventional technologies. Of electric generators, there exist superconducting laboratory and prototype machines only. MHD generators and rotating DC machines using stationary magnetic fields, three-phase ACsynchronous generators with superconducting excitation coils working with rotating fields are of interest for industry world wide. Further applications of superconductivity are in magnetic separation (coal desulfurization), the magnetic suspension railway and in superfast computers using the Josephson effect. V5 Research and development of electronic devices in submicron
H Vernickel, Max-Pianck-lnstitut fdr Plasmaphysik, EURATOM Association, D-8046 Garching, Germany In TOKAMAKS without divertors a large fraction of the heating power ends up at the limiters where therefore plasma-wall interaction is especially severe. Depending on the properties of the boundary plasma and the impurity content of the main plasma between a few per cent and 70% of the heating power has to be taken by the limiter. In the next generation of TOKAMAKS plasma current, energy content of the plasma and energy throughput will be a factor of 5 to 10 larger than at present. In
technology W G6pel, Phys Dept, Montana State University, Bozeman, Montana 59717, USA (on leave of absence from Inst Phys Chemie der Univ, Hannover) The design of very large-scale integrated circuits (VLSI), which is of great technological importance, requires a new generation of instruments and a new array of techniques adequate to give spatial resolution below 1 p. Because of the large wavelength of photons in the visible range, beams of electrons, ions or x-rays 129