Fys-3017 Sheaths and probes in low-temperature plasmas is offered spring 2020.
If you are interested, please contact me by email.
Plasma interaction with walls, e.g. a probe surface, spacecraft or a dust particle in space, leads to he formation of sheaths between the plasma and the wall. Such sheaths can sustain large potential drops over a distance of a few Debye lengths, caused either by applied bias, charging of satellites in space or charged dust particles. Charging of spaceraft can lead to unwanted arcing and damaging of instruments, and hence this mechanism need to be understood in order optimize spacecraft and diagnostic design in space. Most important, to obtain plasma parameters from probes it is crucial to understand how sheaths forms and how the plasma interacts with walls through a sheath.
The course starts with introducing collisions and collisional cross sections and go on to study plasma flux towards walls in plasmas and formation of various types of sheaths. Particle and energy confinement of laboratory plasmas will be discussed, and charging effects on objects in space will be covered.
In particular, the course provides insight in theory and practical applications of probe techniques for low-temperature plasmas in laboratory and space. The theory to obtain plasma parameters from Langmuir diagnostics, ion-energy analysers, emissive probes, Mach probes, and mass spectrometry will be covered in some detail. In addition, the dust detection by antennas and dust instruments developed and implemented at UIT for mesospheric rockets, will be introduced.
Laboratory exercises are central in understanding the various probe methods. Five to six laboratory exercises will be performed, of which a minimum of three laboratory reports with full characterization of a plasma by means of at least three different probe methods needs to be approved prior to final examination, of which one report will count 20% at the final examination.
Prior to the laboratory experiments, necessary safety instructinos are given.