Studies of plasma potential with emissive probes in the low temperature plasma experiment NJORD
In this thesis, the concept of an emissive probe has been used to obtain the plasma potential in the low temperature plasma experiment NJORD. An emissive probe is a probe concept in which a wire is heated strong enough to emit a Richardson current. The probe is then swept through several voltage biases and thus, an I-V trace obtained. With the current from the emission and the collected current, this gives in principle very easy access to the plasma potential. NJORD is a plasma discharge driven by a radio frequency in what is called helicon range. This specifies a small frequency band of oscillations that connect well to the electrons. While having good heating properties, it induces a set of problems for the emissive probe due to the oscillations. Applying modelling and monitoring how the recorded traces deviate from the expected ideal traces, however, gives some insight into the physical processes taking place and made it possible to prove the existence of a second electron population. Observing two electron populations with this concept is a novelty and could help completing the theory behind the so called "helicon double layer thruster" concept.
ForlagUniversitetet i Tromsø
University of Tromsø
Følgende lisensfil er knyttet til denne innførselen:
Viser innførsler relatert til tittel, forfatter og emneord.
Tribulato, Giulio (Master thesis; Mastergradsoppgave, 2007-06)Njord is a novel plasma device in which a low-temperature plasma is produced by RF waves inductively coupled into a cylindrical, magnetized vacuum. The main part of this project is to carry out an experimental characterization of the plasma in this device. The plasma expansion and acceleration of the source plasma into the main chamber will be of specific interest. The ultimate aim will then be to ...
Schots, Pauke Carlijn (Master thesis; Mastergradsoppgave, 2015-05-15)Mariposia, voluntarily drinking seawater, has been studied for several decades in marine mammals. Although the ingestion of seawater has been studied in several marine mammal species, knowledge about water balance and water flux in hooded seals is still limited. The purpose of this study is to evaluate the importance of exogenous water intake (snow/seawater) for maintenance of body water in hooded ...
Osnes, Sindre (Master thesis; Mastergradsoppgave, 2017-06-06)We study the effect of changing the separation grid bias in a double plasma device from -50 V to the same bias as the anode in the source chamber, 115 V on the plasma and beam parameters downstream in the target chamber. Two different probes were used to analyze the downstream plasma. We used an RFEA-probe to obtain information about the ions, such as the ion energy distribution and we constructed ...