Installation and characterization of an electron bombardment ion source for a Space Simulation Chamber (SSC)

Abstract

The primary focus of this thesis is the installation and characterization of an electron bombardment ion source for a Space Simulation Chamber (SSC). The goal is that the chamber can be used to test satellite and sounding rocket instrumentation, thus be capable of producing ionospheric plasma conditions, along with an ion beam that can simulate the velocity of a rocket or satellite relative to the atmosphere. The plasma also need to be reproductive.

First, the plasma source was prepared for operation after years in storage. This included changing the filaments and checking the conditions of the electrical connections and magnetic field. A new setup of power sources for the different components was also done.

Second, the source was installed and characterized in the Space Simulation Chamber. Some hang ups were encountered and solved.

Two different electrostatic probes were used to analyse the plasma. A basic Langmuir probe, useful for finding parameters like the plasma potential, electron temperature and plasma density, and a retarding field energy analyzer (RFEA) for finding the ion saturation current and ion energy distribution.

Some inconsistency was found in the plasma potential between the two probes, seemingly indicating the presence of an ion beam. The plasma density is in the order of $10^{11} ~cm^3$ and the electron temperature is in the range 3-5 eV and can be varied using the neutralizing filament.