Effects of magnetic perturbations and radiation on the runaway avalanche
Typ
Examensarbete för masterexamen
Program
Physics and astronomy (MPPAS), MSc
Publicerad
2020
Författare
Svensson, Pontus
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Electron runaway is seen as one of the main threats to reliable operation of magnetic
confinement fusion reactors, and is an issue only predicted to worsen as reactors are
scaled up. The runaway phenomenon depends fundamentally on momentum space
dynamics, but to simulate large scale systems effective theories which depend only
on spatial quantities are often employed. In this thesis, we will address how a momentum
space dependent diffusive transport, which appears as a consequence of
imperfect confining magnetic fields, can be incorporated into this type of model. A
scheme to correct the generation of runaway electrons due to this transport, which
incorporates the effect of radiation reaction forces, is proposed. The corrected generation
of runaway electrons is formulated as a solution to an integral equation, for
which a numerical solver is implemented. The effect of the model is investigated for
diffusion coefficients inspired by electron diffusion in stochastic magnetic fields where
a reduced generation and a larger critical electric field for the runaway generation
is observed.
Beskrivning
Ämne/nyckelord
fusion , runaway electrons , radial diffusion , radiation reaction force