Citations Index >>>

Articles With Citations to Z. Abou-Assaleh

Theoretical Plasma Physics

Controlled Thermonuclear Fusion Energy

2022

Modelling of Kinetic E ects in Parallel Transport
in the Tokamak Scrape-O Layer
Stefan Mijin

Submitted in part ful lment of the requirements
for the degree of Doctor of Philosophy in Physics at
Imperial College London.
 

Department of Physics
The Blackett Laboratory
Imperial College London
SW7 2AZ

https://spiral.imperial.ac.uk/handle/10044/1/83170
....

...

Bibliography

...

[70]  Z. Abou-Assaleh, M. Petravic, R. Vesey, J. P. Matte, and T. W. Johnston, \Non-Local

Transport in a Tokamak Plasma Divertor with Recycling," Contributions to Plasma

Physics, vol. 34, no. 2-3, pp. 175{179, 1994.

[71]  R. J. Procassini and D. A. Knoll, \Kinetically motivated boundary conditions for uid

models of scrape-o
layer transport," Journal of Nuclear Materials, vol. 196-198, no. C,

pp. 363{368, 1992.

[72]  Z. Abou-Assaleh, J. P. Matte, T. W. Johnston, and R. Marchand, \Fokker-Planck

Modelling of Edge Plasma Near the Neutralizer Plate in a Tokamak," Contributions to

Plasma Physics, vol. 32, no. 3/4, pp. 268{272, 1992.

[73]  J. P. Matte and J. Virmont, \Electron heat transport in a steep temperature gradient,"

Physical Review Letters, vol. 49, no. 26, pp. 1936{1939, 1982.

...

Title: Modelling of kinetic effects in parallel transport in the tokamak scrape-off layer

Authors: Mijin, Stefan

Item Type: Ph.D. Thesis or dissertation

Abstract:

Heat flow onto divertor targets in the tokamak represents one of the main design problems in current fusion research. Excessive heat loads, especially during violent transient events, can significantly damage the plasma-facing components. In order to mitigate the heat load it is beneficial to run the tokamak in a detached regime. This involves formation of a neutral cloud in front of the divertor targets that protects the surface material. Thus interaction of the plasma with the detached neutrals becomes important.Energy, on its way to the divertor targets, travels through the boundary region of the tokamak, the Scrape-Off Layer. The main transport direction is parallel to the open magnetic field lines of the Scrape-Off Layer. Fluid models are routinely used to simulate particle and energy transport in the boundary region, but these fail to capture kinetic effects, which have been linked to discrepancies between said fluid model predictions and experimental data[1]. Kinetic/non-local effects have been observed in simulations of parallel transport, including heat flux suppression and enhancement[2], as well as effects on ionisation rates[3]. The plasma sheath at the divertor target is also affected by non-local phenomena[4,5]. Exploring how kinetic effects change facets of parallel transport, and especially how they cause departure from widely used fluid models, is important in furthering our understanding of heat load issues, which are critical to future machine design.In this thesis, a novel framework for studying electron kinetic effects in parallel transport is developed, with special focus on the proper treatment of the sheath boundary condition and inelastic collisions, and the capability of self-consistent comparison between a kinetic and fluid model. This framework is implemented in the new electron kinetic code SOL-KiT, and details on the model and numerics, as well as benchmarking, are presented.With the developed code, a systematic power scan study of non-local effects in both equilibria and transients has been conducted. Kinetic effects are found to be especially prominent in the interaction of transients with detachment, where heating due to fast particles, heat flux suppression, as well as modification of ionisation rates have been observed.

https://spiral.imperial.ac.uk/handle/10044/1/83170

Measurement of Mach probe on plasma flow velocity in highly collisional plasma jetIn Je Kang*, Hyonu Chang, Yong-Sup Choi, Soo Ouk Jang, Chang Hyun Cho, Ji Hun Kim, Hyun Jae Park

Institute of Plasma Technology, Korea Institute of Fusion Energy, Gunsan, 54004, South Korea

Current Applied Physics >>>

Abstract

A normalized plasma flow velocity in highly collisional plasma formed by a microwave plasma jet, which is dimensionless unit for plasma flow velocity/ion acoustic velocity, was measured by the parallel Mach probe. To deduce the normalized plasma flow velocity under highly collisional plasma conditions, the collisional model of a Mach probe was proposed. In addition, neutral gas flow velocity which assumed to be plasma flow velocity was calculated by the turbulent model. The results for the two different models were compared with those for the collsionless models of the Mach probe. The turbulent model produced 2–4 times reduced values than by measurements with collsionless models. The measured results with the collisional model were shown as approximately 100–250% lower than those for collsionless models. They were obtained to be in good agreement with difference rate of 10–30% when compared to those for the turbulent model.

Reference

....

[4]  S.L. Gulick, B.L. Stansfield, Z. Abou-Assaleh, C. Boucher, J.P. Matte, T.W. Johnston, R. Marchand, Measurement of pre-sheath flow velocities by laser-induced fluorescence, J. Nucl. Mater. 176 (1990) 1059, https://doi.org/10.1016/0022- 3115(90)90192-P.

....

Citations Index >>>