Device for mapping ion beam diagnostics helps optimize electric propulsion systems

Electric propulsion systems for small spacecraft require thrusters that generate high-quality ion beams. These beams must be collimated and symmetrical to prevent off-axis thrust, which can increase power and propellant use. Habl et al. created an automated plume diagnostic for mapping ion beam generation of miniaturized electric propulsion devices.

This miniaturized device helps optimize beam generation by producing 2D mapping of the ion beam cross section. These maps can be used to calculate performance estimates such as total ion current and effective divergence angle.

Beam intensities can be typically described by a gaussian distribution function. By installing probes that follow such a configuration on their instrument, the authors found they were able to improve mapping resolution and quality.

“Since the array measures the current density distribution in the downstream region of the plasma expansion, its applicability is not limited to one specific type of plasma source. This way, as long as the ion beam meets certain criteria, the instrument can be employed for its characterization,” said author Lui Habl.

The authors intend on improving aspects of the design, such as the resistance of the corrosive action of the iodine, optimization of the probe design, and a measurement system for the angular position of the instrument.

“We discovered that there is no available data about the secondary electron emission caused by the iodine ion impact on metals and are currently expanding on the first measurements presented in this article to determine this property for different target materials,” said Habl. “This is crucial for the space propulsion community, since iodine has proven to be a very promising alternative propellant for electric thrusters, due to its mass and the possibility of storing it in solid state.”

Source: “Ion beam diagnostic for the assessment of miniaturized electric propulsion systems,” by L. Habl, D. Rafalskyi, and T. Lafleur, Review of Scientific Instruments (2020). The article can be accessed at https://doi.org/10.1063/5.0010589 .