Dynamics of metallic dust particles in tokamak edge plasmas
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
The study of dust dynamics in tokamaks has been carried out by means of the DDFTU numericalcode solving the coupled equations of motion, charging and heat balance for a dust grainimmersed in plasmas with given profiles. The code has been updated to include (i) a non-steadystate heat balance model and phase transitions, (ii) geometrical properties of the vessel suchas gaps, (iii) realistic boundary conditions for dust-wall collisions. The models for secondaryelectron emission (SEE), thermionic emission and black body radiation have also been refined,and sensitivity of the results to the SEE strength is demonstrated.
The DDFTU code has been used for the first time to explore a large range of initial conditions(position, velocity and radius) for dust grains of various tokamak-relevant materials. This studyconfirmed the impact of the drag force as one of the main factors in dust dynamics and allowedto estimate average lifetimes, to locate preferred sites for dust deposition and to judge thesensitivity to initial conditions. This is a first step towards the use of the code as a predictivetool for devices of importance, such as JET and ITER.
Preliminary simulations of scenarios relevant for dust injection experiments in TEXTOR haveyielded results in remarkable agreement with experimental data.
These preliminary studies allowed to identify the most crucial issues affecting dust dynamics,lifetime, deposition rate and contribution to impurities, which are to be pursued in futurestudies.
Place, publisher, year, edition, pages
2013. , 93 p.
Plasma physics, dust, tokamak edge plasma
Fusion, Plasma and Space Physics Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-118454OAI: oai:DiVA.org:kth-118454DiVA: diva2:606245
Subject / course
Master of Science in Engineering - Electrical Engineering
UppsokPhysics, Chemistry, Mathematics