Calculation and Measurement of the Neutron Emission Spectrum due to Thermonuclear and Higher-Order Reactions in Tokamak Plasmas

• A series of analytic and numerical models have been developed for the prediction and interpretation of the energy spectrum of the neutron emission from thermonuclear deuteriumtritium (DT) plasmas. The main component of the neutron emission, due to reactions between thermal fuel ions, has been modeled as well as minority components due to the presence of fast (supra-thermal) ions. In particular, the so-called alpha-particle knock-on neutron (AKN) emission has been analyzed and found to carry information on the con- finement of fast alpha particles inside the plasma. The alpha particles carry one fifth of the fusion power generated in the plasma and provide the plasma self-heating. This thesis is devoted to this central endeavor of fusion research and the possibilities for its study in today’s largest magnetic confinement devices, the tokamaks.The developed models have been used for the interpretation of experimental data taken during the first deuterium-tritium experiment (DTE1) at the Joint European Torus (JET) in 1997. The data were taken with a neutron spectrometer of the magnetic proton recoil (MPR) type developed at the Department of Neutron Research (INF) of Uppsala University. The MPR was used to measure the neutron emission from DT plasmas representing record high fusion power levels of up to 16 MW and correspondingly high quality in the neutron emission observations. These studies in DT plasmas were complemented with theoretical and empirical studies of the 14-MeV triton burn-up neutron (TBN) emission from deuterium plasmas.The predicted neutron energy spectra were found to be able to describe observations leading to positive identification of previously unobserved spectral features such as the very weak AKN and TBN signature in the neutron emission. In this summary, the developed models are presented as well as the experimental findings. Finally, a discussion is included of the possible application of the presented models and experimental techniques to next-step fusion experiments such as the proposed ITER tokamak.

Ämnesord

NATURVETENSKAP  -- Fysik -- Subatomär fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Subatomic Physics (hsv//eng)

Nyckelord

Nuclear physics

Kärnfysik

Nuclear physics

Kärnfysik

Applied Nuclear Physics

tillämpad kärnfysik

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