The PhD defence and trial lecture will be streamed. The chair of the defence will moderate the disputation.
Ex auditorio questions: the chair of the defence will invite the audience physically present in the auditorium to ask ex auditorio questions.
→ Live streaming of trial lecture and disputation
→ Request for thesis copy (available until the disputation starts)
Trial lecture
Time and place: April 19, 2024; 10:15 AM, Lille Fysiske Auditorium (V232) - Fysikkbygningen
Title: “Comparing lunar surface charging, lunar regolith charging, and spacecraft charging on lunar surface - plasma interactions at three different length scales ”
Main research findings
Did you know that in the vacuum of space, there is no vacuum? In fact, most of space is filled with charged particles in a plasma state. Close to Earth, Geomagnetic phenomena, space weather, and radio interference such as GPS scintillation are all explained with plasma dynamics. Space is also the largest laboratory we have for plasma physics. It is, therefore, no surprise that accurate measurements of the surrounding plasma of a spacecraft are a part of the foundation for understanding our own ionosphere. A common approach to probing a plasma is with Langmuir probes, which are conducting objects that collect an electrical current, from which we can infer plasma parameters, usually using orbital-motion-limited (OML) theory. It is known that OML will be erroneous under certain conditions. However, due to the complexity and scales of the problem, several sources of error have not been adequately studied and are therefore not well understood or accounted for. In this dissertation, we use Particle-in-Cell simulations to further our understanding by uncovering limits to the idealized OML theory and building models to correct several such error sources. The thesis focuses on charged-neutral collisional effects, the effects of imperfect geometries, and probes in magnetized plasmas.
Adjudication Committee
- Professor Joseph J. Wang, University of Southern California
- Professor Em. Åshild Fredriksen, UiT The Arctic University of Norway
- Professor Anders Malthe-Sørenssen, University of Oslo
Supervisors
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Professor Wojciech Jacek Miloch, Department of Physics, University of Oslo, Norway
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Professor Hideyuki Usui, Graduate School of System Informatics, Kobe University, Japan
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Professor Yohei Miyake, Graduate School of System Informatics, Kobe University; Japan
Chair of defence
Professor Andreas Görgen, Department of Physics, University of Oslo, Norway
Candidate contact info
Phone number: 90676098
E-mail: steffen_brask@hotmail.com
Contact information to Department: Line Trosterud Resvold