Skapa referens, olika format (klipp och klistra)
Harvard
Hoppe, M. (2017) Synthetic synchrotron diagnostics for runaways in tokamaks. Göteborg : Chalmers University of Technology
BibTeX
@mastersthesis{
Hoppe2017,
author={Hoppe, Mathias},
title={Synthetic synchrotron diagnostics for runaways in tokamaks},
abstract={In tokamaks, highly relativistic electrons known as runaway electrons may be created,
for example during disruptions when instabilities rapidly grow and cause operation
to abruptly terminate. If control of the runaway beam is lost, the electrons
can collide with the device wall and inflict severe damage. Therefore, it is of great
importance to understand the processes that give rise to and govern the behaviour
of these particles. One of the best ways to learn about the phase-space distribution
of runaway electrons in experiments is to measure the synchrotron radiation emitted
by them, often in the visible or infrared wavelength ranges, by making camera
images or measuring the spectrum. Synchrotron radiation is emitted almost entirely
in the forward direction of the electron, contrary to how light is usually emitted by
most other light sources, and because of this electrons must be moving towards the
observer in order to be seen. As a result, most electrons are invisible to the observer
most of the time, and the synchrotron image does not reveal the full runaway beam,
rather showing an abstract spot of light that can take on many different shapes. The
sharp beaming in the forward direction of synchrotron radiation however puts an
extra constraint on the image which allows the full velocity vector of the runaways
to be inferred from the image.
In this thesis the numerical tool SOFT (for Synchrotron-detecting Orbit Following
Toolkit), along with the theory on which it builds, is presented. With SOFT,
synchrotron images from runaway populations that are arbitrarily distributed in
phase-space can be simulated, taking various kinds of geometric effects (magnetic
field geometry, camera placement, viewing direction etc.) into account. The effects
on the image due to isolated variations in energy, pitch angle, minor radius
and camera location are investigated and analysed. Synchrotron images simulated
with analytical avalanche distributions of runaways are interpreted in relation to,
and compared with, synchrotron images from mono-energetic runaway populations.
All parameters are found to have distinct effects on the synchrotron spot, and it is
shown that the synchrotron images due to full distributions of runaway electrons
can partly be understood as dominated by particles of a particular energy and pitch
angle},
publisher={Institutionen för fysik (Chalmers), Chalmers tekniska högskola},
place={Göteborg},
year={2017},
keywords={fusion, runaway, synchrotron, guiding-center, SOFT},
note={80},
}
RefWorks
RT Generic
SR Electronic
ID 249436
A1 Hoppe, Mathias
T1 Synthetic synchrotron diagnostics for runaways in tokamaks
YR 2017
AB In tokamaks, highly relativistic electrons known as runaway electrons may be created,
for example during disruptions when instabilities rapidly grow and cause operation
to abruptly terminate. If control of the runaway beam is lost, the electrons
can collide with the device wall and inflict severe damage. Therefore, it is of great
importance to understand the processes that give rise to and govern the behaviour
of these particles. One of the best ways to learn about the phase-space distribution
of runaway electrons in experiments is to measure the synchrotron radiation emitted
by them, often in the visible or infrared wavelength ranges, by making camera
images or measuring the spectrum. Synchrotron radiation is emitted almost entirely
in the forward direction of the electron, contrary to how light is usually emitted by
most other light sources, and because of this electrons must be moving towards the
observer in order to be seen. As a result, most electrons are invisible to the observer
most of the time, and the synchrotron image does not reveal the full runaway beam,
rather showing an abstract spot of light that can take on many different shapes. The
sharp beaming in the forward direction of synchrotron radiation however puts an
extra constraint on the image which allows the full velocity vector of the runaways
to be inferred from the image.
In this thesis the numerical tool SOFT (for Synchrotron-detecting Orbit Following
Toolkit), along with the theory on which it builds, is presented. With SOFT,
synchrotron images from runaway populations that are arbitrarily distributed in
phase-space can be simulated, taking various kinds of geometric effects (magnetic
field geometry, camera placement, viewing direction etc.) into account. The effects
on the image due to isolated variations in energy, pitch angle, minor radius
and camera location are investigated and analysed. Synchrotron images simulated
with analytical avalanche distributions of runaways are interpreted in relation to,
and compared with, synchrotron images from mono-energetic runaway populations.
All parameters are found to have distinct effects on the synchrotron spot, and it is
shown that the synchrotron images due to full distributions of runaway electrons
can partly be understood as dominated by particles of a particular energy and pitch
angle
PB Institutionen för fysik (Chalmers), Chalmers tekniska högskola,
LA eng
LK http://publications.lib.chalmers.se/records/fulltext/249436/249436.pdf
OL 30
