This title appears in the Scientific Report :
2018
Please use the identifier:
http://hdl.handle.net/2128/18381 in citations.
The Dynamics of Electrons in Linear Plasma Devices and its Impact on Plasma Surface Interaction
The Dynamics of Electrons in Linear Plasma Devices and its Impact on Plasma Surface Interaction
For the viable operation of a thermonuclear fusion reactor, large pressure gradients are necessary in the edge of a magnetically conned plasma device. Turbulent cross-field transport across these gradients severely limits the durability of the current reactor designs by the erosion of plasma facing...
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Personal Name(s): | Hubeny, Michael (Corresponding author) |
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Contributing Institute: |
Plasmaphysik; IEK-4 |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2018
|
Physical Description: |
141 S. |
Dissertation Note: |
Universität Bochum, Diss., 2017 |
ISBN: |
978-3-95806-316-7 |
Document Type: |
Book Dissertation / PhD Thesis |
Research Program: |
Plasma-Wall-Interaction |
Series Title: |
Schriften des Forschungszentrums Jülich Reihe Energie & Umwelt / Energy & Environment
418 |
Link: |
OpenAccess |
Publikationsportal JuSER |
For the viable operation of a thermonuclear fusion reactor, large pressure gradients are necessary in the edge of a magnetically conned plasma device. Turbulent cross-field transport across these gradients severely limits the durability of the current reactor designs by the erosion of plasma facing components. The convective character of this transport is caused by intermittently occurring plasma laments, which are observed with similar characteristics in the edge of a wide range of plasma devices. Besides the ballistic plasma transport, laments lead to pressure fluctuation statistics with a positive skewness and kurtosis, i.e. short, local spikes in density and temperature time traces. Erosion predictions based on time-averaged measurements underestimate dynamic effects on erosion mechanisms, e.g. the sputtering yield, due to its non-linear temperature dependence. The aim of this thesis was the development of a time-resolved laser Thomson scattering diagnostic system to investigate plasma dynamics leading to and during intermittent transport events, which were identied at the linear plasma generator PSI-2 in high powered, steady state Deuterium discharges with fast visual imaging. To retain the temporal information in the Thomson scattering setup, the signal was recorded in a triple grating spectrometer on a shot-to-shot basis with a photon counting method. The synchronization of the Nd:YAG laser and spectrometer to a fast framing camera allowed the novel usage of conditional averaging to create Thomson spectra. The selection of a subset of laser pulses with conditions in time andspace was based on the plasma state characterized by 100 captured frames aroundeach laser pulse with a time resolution of 3 $\mu$s. |