dc.contributor.author | Ropponen, Tommi | |
dc.date.accessioned | 2010-03-02T09:41:16Z | |
dc.date.available | 2010-03-02T09:41:16Z | |
dc.date.issued | 2010 | |
dc.identifier.isbn | 978-951-39-3784-3 | |
dc.identifier.other | oai:jykdok.linneanet.fi:1124188 | |
dc.identifier.uri | https://jyx.jyu.fi/handle/123456789/23007 | |
dc.description.abstract | This thesis is a study of Electron Cyclotron Resonance Ion Source (ECRIS) plasmas
and their properties. The focus has been on time evolution studies of bremsstrahlung
emission, ion beam current production and numerical studies of electron heating in
ECRIS plasmas. The time scales for reaching steady state bremsstrahlung production
at electron energies greater than 30 keV is shown to be on the order of several
hundreds of milliseconds. The ion beam currents of different elements are shown to
reach steady state before the bremsstrahlung production. It is also demonstrated that
by tuning the RF pulse patterns, the so-called preglow transient ion beam currents
can be utilized while the amount of bremsstrahlung radiation can be significantly
reduced. In numerical work it has been found, for example, that the number of
high energy electrons decreases when the microwave power absorption has been
modeled.
The thesis is divided in the following way: Chapter 1 is a short introduction to
the ECR ion source field including motivation to electron heating studies; Chapter
2 contains basic properties of plasma physics that are needed to understand the
behaviour of plasmas; Chapter 3 introduces the reader to ECR ion sources, operational
principles and mechanisms dictating the production of highly-charged ions;
Chapter 4 concentrates on electron heating via microwaves, describing limitations in
the heating processes. The model for the electromagnetic (EM) wave absorption and
the description of the simulation code developed in this thesis work are presented.
In addition, properties of some of the existing electron heating / ECRIS codes are
discussed. Chapter 5 deals with the bremsstrahlung production, discusses some of
the previous bremsstrahlung measurements and presents the experimental apparatus.
Chapter 6 contains the summary of the numerical and experimental results, and Chapter 7 concludes the thesis. | en |
dc.format.extent | 77, [60] sivua | |
dc.language.iso | eng | |
dc.publisher | University of Jyväskylä | |
dc.relation.ispartofseries | Research report / Department of Physics, University of Jyväskylä | |
dc.relation.isversionof | ISBN 978-951-39-3783-6 | |
dc.subject.other | ECRIS | |
dc.subject.other | bremsstrahlung time evolution | |
dc.subject.other | microwave power absorption | |
dc.title | Electron heating, time evolution of bremsstrahlung and ion beam current in electron cyclotron resonance ion sources | |
dc.type | Diss. | |
dc.identifier.urn | URN:ISBN:978-951-39-3784-8 | |
dc.type.dcmitype | Text | en |
dc.type.ontasot | Väitöskirja | fi |
dc.type.ontasot | Doctoral dissertation | en |
dc.contributor.tiedekunta | Matemaattis-luonnontieteellinen tiedekunta | fi |
dc.contributor.tiedekunta | Faculty of Mathematics and Science | en |
dc.contributor.yliopisto | University of Jyväskylä | en |
dc.contributor.yliopisto | Jyväskylän yliopisto | fi |
dc.contributor.oppiaine | Fysiikka | fi |
dc.relation.issn | 0075-465X | |
dc.relation.numberinseries | no. 1/2010 | |
dc.rights.accesslevel | openAccess | fi |