Plasma density measurements with atomic beams

Eubank, H. P.; Noll, P.; Tappert, F. D.

doi:10.1088/0029-5515/5/1/009

Cited by 29 publications

(11 citation statements)

References 11 publications

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“…By the late 1970s, various tokamaks were starting to employ auxiliary heating systems, primarily neutral beam injection (NBI). Experiments with NBI on PLT resulted in the achievement of the first thermonuclear class temperatures [81,98,99]. PLT at the time used tungsten limiters, and, at high NBI powers and relatively low plasma densities, very high edge plasma temperatures and power fluxes were generated, resulting in tungsten sputtering and high core radiation from partially stripped tungsten impurity ions.…”

Section: Plasma Facing Materialsmentioning

confidence: 99%

Plasma-material interactions in current tokamaks and their implications for next step fusion reactors

et al. 2001

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The major increase in discharge duration and plasma energy in a next step DT fusion reactor will give rise to important plasma-material effects that will critically influence its operation, safety and performance. Erosion will increase to a scale of several centimetres from being barely measurable at a micron scale in today's tokamaks. Tritium co-deposited with carbon will strongly affect the operation of machines with carbon plasma facing components. Controlling plasma-wall interactions is critical to achieving high performance in present day tokamaks, and this is likely to continue to be the case in the approach to practical fusion reactors. Recognition of the important consequences of these phenomena stimulated an internationally co-ordinated effort in the field of plasma-surface interactions supporting the Engineering Design Activities of the International Thermonuclear Experimental Reactor project (ITER), and significant progress has been made in better understanding these issues. The paper reviews the underlying physical processes and the existing experimental database of plasma-material interactions both in tokamaks and laboratory simulation facilities for conditions of direct relevance to next step fusion reactors. Two main topical groups of interaction are considered: (i) erosion/redeposition from plasma sputtering and disruptions, including dust and flake generation and (ii) tritium retention and removal. The use of modelling tools to interpret the experimental results and make projections for conditions expected in future devices is explained. Outstanding technical issues and specific recommendations on potential R&D avenues for their resolution are presented.

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Section: Plasma Facing Materialsmentioning

confidence: 99%

Plasma-material interactions in current tokamaks and their implications for next step fusion reactors

et al. 2001

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“…In general, atom beam methods can be used for densities between 10 10 and 10 14 cm~3, whereas Thompson scattering of photons has its advantages for densities above 10 13 -10 14 cm~3 (Dimock et al 1971). We note that neutral atom beams (Finlayson et al 1972;Osher 1965;Kikoin et al 1964;Krupnik & Shulika 1965;Eubank et al 1965;Kislyakov & Petrov 1971) have the advantage over charged-particle beams in that they are not perturbed by the strong constant or time varying electric and magnetic fields found in fusion machines. In its simplest mode of operation, the attenuation of the beam is caused by atomic interactions and is directly related to the •f Permanent address.…”

Section: Introductionmentioning

confidence: 82%

Analytical study of crossed atom-laser beam plasma diagnostics

Nygaard

1976

J. Plasma Phys.

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A new method using crossed laser and atom beams within a plasma is capable of determining the electron density with a spatial resolution of 1 mm and a time resolution of 2–5 nsec. The measurement is done in the forward direction of the atom beam and is to a first approximation independent of electric and magnetic fields inside and outside the plasma region. A calculation is carried out for a neutral cesium beam probing a fully ionized hydrogen plasma. It is pointed out that a laser beam can also be combined with available ion beam diagnostics.

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“…Electric fields, magnetic fields, density, electron and ion temperatures have all been characterized by one or more such system (EUBANK et al, 1965;JOBES and HICKOK, 1967;KADOTA et al, 1978;MCCORMICK et al, 1977;REINOVSKY et al, 1974). In all cases, injected ion or neutral beams collide with some constituent of the plasma; either light is emitted or the charge state of the particles is changed.…”

Section: Introductionmentioning

confidence: 99%