The Institute of Plasma Physics and Laser Microfusion's (IPPLM) Hall effect thruster (Krypton Large IMpulse Thruster, KLIMT) is a 500 W class plasma engine with a mean diameter of discharge channel of 42 mm. KLIMT was developed within ESA/PECS project aiming to provide relatively small thruster for satellites that would be able to effectively operate with krypton propellant. Being several times less expensive than xenon, which is regarded as a propellant of choice for electric propulsion of electrostatic type, krypton since years has been suggested as an attractive alternative. In this paper, a design as well as performance tests of the laboratory model of KLIMT are discussed. It is shown that precise adjustment of magnetic field topography results in the stable operation of the thruster in wide range of operating conditions providing similar thrust and specific impulse production for both propellants. Maximum thrust produced with the use of xenon and krypton reached about 16–17 mN for mass flow rate of 1.15–1.2 mg/s resulting in specific impulse in the range of 1300–1500 s (13–15 km/s). However, for krypton the anode efficiency drops by ~10% in comparison with xenon. For krypton plasma beam divergence as measured by an average half-angle with respect to the beam axis was found to remain within the range of 19–23° for the whole set of the examined operating conditions. The reported characteristics are reasonable for Hall thruster of the discussed size and power.

Krypton Large Impulse Thruster (KLIMT) project was aimed at incremental development and optimization of a 0.5 kW-class plasma Hall Effect Thruster in which, as a propellant, krypton could be used. The final thermally stable version of the thruster (the third one) was tested in the Plasma Propulsion Satellites (PlaNS) laboratory in the Institute of Plasma Physics and Laser Microfusion (IPPLM) in Warsaw as well as in the European Space Agency (ESA) propulsion laboratory in the European Space Research and Technology Centre (ESTEC).During final measurement campaign, a wide spectrum of parameters was tested. The plasma potential, electron temperature, electron concentration, and electron energy probability function in the far-field plume of the thruster were measured with a single cylindrical Langmuir probe. Faraday probes were used for recording local values of ion current. Using several collectors in different locations and moving them on the surface of a sphere, the angular distribution of the expelled particles was reconstructed which was a local measure of beam divergence. Angular distribution of ion flux as measured with a central Faraday probe was parameterized with krypton mass flow rate, voltage, coil current ratio, and the cathode mass flow rate. Beam divergence measurements with Faraday probes as well as plasma parameters derived from Langmuir probe seem to be consistent with our understanding of the operating envelope. Obtained results will serve as a baseline in the design of plasma beam structure diagnostics system for the PlaNS laboratory.

The magnetic circuit of a 500 W class Hall thruster, an electric propulsive device for spacecraft, was characterized experimentally and the results compared with simulation in order to verify the design. The commercial 3D gaussmeter, which was used in this work, was additionally recalibrated to compensate for translation and rotation of individual Hall sensors inside the probe. The Stokes stream function approach was applied to reconstruct the magnetic field topography in the thruster. The procedure, carried out on four different cases, yielded very good agreement between simulations and measurements, even for cusped configurations. Presented technique could be used as a robust method of verification of new magnetic circuit designs not only for Hall thrusters but also for a wide class of plasma devices for which detailed knowledge about actual distribution of magnetic field is crucial for optimization.