Gridded Ion Thruster - Plume Study
Problem
The understanding of plasma properties in the plume is critical for spacecraft performance. Plume interaction with the spacecraft can cause significant challenges, including:
- Surface erosion, charging and contamination
- Interference with electronics
- Sensor performance degradation
Current experimental approaches to measure plume properties of a gridded ion thruster reveal significant limitations.
- No plume flow field scaling laws exist for translating ground test results to orbital conditions
- Test facilites constrained by size, mass flow rates, and power specifications
- Disturbance of the plume due to invasive mechanical plasma diagnostic probes
Attempting to simulate the plume with standard tools proves to be difficult as the required inflow conditions that need to be provided are usually hard or even impossible to get with desired quality and reliability.
Solution
VSTRAP enables comprehensive ab-initio plume modelling without experimental dependencies.
Advanced simulation capabilities
- Models complete plume characteristics from thruster design parameters
- Accounts for grid curvature and non-uniform particle and energy distribution
- Simulates both high-energy primary ions and low-energy CEX ion populations
- Predicts plume behavior in both vacuum chamber and space environments
- Validated against RIT-22 thruster data in ESA project
Practical benefits:
- De-risk test campaigns through predictive analysis
- Evaluate thruster designs without physical prototyping
- Accurate assessment of spacecraft interaction effects
By following this workflow, the overall simulation domain gets extended upstream, and the inflow condition for the plume solver is constructed on basis of upstream phenomena and under consideration of gridded ion optic specific particle and energy profiles.
VSTRAP-GIT is designed to automatically import the configuration and the results of a previously configured gridded ion optics simulation into the plume simulation!
Results
The end-to-end simulation yields very good comparison with experimentally obtained radial profiles if facility effects remain within bounds – as well as the plasma disturbances caused by the mechanical probes. The following example demonstrates the power of predictivity increase by simulation domain extension via upstream coupling.
Visualization of the ion densities and current densities extruded by a RIT-22 thruster
Summary
VSTRAP-GIT QN Plume extends the single aperture ion optics simulation of the near field to the far field with an easy to use and validated plume configurator.
- Measure plume properties without the interference from mechanical plasma diagnostics tools
- Easy-to-configure beam construction based on thruster design parameters
- Automated import of the configuration from a single aperture ion optic simulation
