3D Sweep Faraday Probe for Hall Thruster Plume Mapping
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Solution Overview
Problem
Existing technologies for measuring ion beam current densities in Hall Effect Thrusters (HETs) face challenges such as non-uniformities due to manufacturing defects, which can lead to variations in plasma properties and thrust vector deviations, and are often costly and complex.
Innovation Solution
A hemispherical sweep probe apparatus that sweeps a Faraday probe vertically across the plasma plume while radially spanning to gather three-dimensional ion currents, providing a cost-effective and modular solution for measuring ion beam current densities and characterizing plasma non-uniformities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional multi-probe measurement systems are used to measure ion beam current densities, then measurement coverage and data completeness are improved, but device complexity and cost increase significantly
Solution Approach 1:
The measurement process is segmented into multiple sequential sweeps along different spatial paths (radial and azimuthal directions). A single probe collects data in stages by moving through different positions, replacing the need for multiple simultaneous probes. This segmentation transforms a complex multi-probe system into a simpler single-probe system that achieves equivalent measurement coverage through temporal rather than spatial parallelism.
Solution Approach 2:
The invention adds the time dimension to the measurement process by performing sequential sweeps at different angular positions and radial distances. Instead of capturing all spatial information simultaneously in three dimensions, the system measures two-dimensional cross-sections at multiple time points and angles, reconstructing the full three-dimensional ion beam characteristics through temporal sequencing of spatial measurements.
2Reliability
If acceptance testing is conducted on all HETs to ensure performance requirements, then reliability is improved, but productivity decreases due to the time-consuming nature of testing
Solution Approach 1:
The measurement system performs targeted partial sweeps rather than complete exhaustive mapping for routine acceptance testing. By measuring only critical regions or performing reduced angular sweeps, the system obtains sufficient data to assess thruster performance and detect manufacturing defects without requiring full three-dimensional characterization, thereby reducing test time while maintaining reliability.
3Ease of manufacture
If computational methods are used to characterize azimuthal non-uniformities, then measurement cost is reduced, but measurement precision and direct observation capability deteriorate
Solution Approach 1:
The single physically-swept probe acts as an intermediary between the complex multi-probe measurement systems and simple stationary single-point measurements. By mechanically sweeping the probe through multiple positions and using computational reconstruction algorithms, the system achieves direct physical measurement of ion beam characteristics with accuracy comparable to multi-probe systems, while maintaining the cost and simplicity of a single probe design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The sweep probe apparatus achieves precise and repeatable measurements of ion beam current densities with minimal deviations, enabling comprehensive three-dimensional mapping of the plasma plume and quantification of the thrust vector's position, thereby addressing the challenges of non-uniformities and cost-effectiveness.
Implementation Method 1
A hemispherical sweep probe apparatus that sweeps a Faraday probe vertically across the plasma plume while spanning radially to gather three-dimensional ion currents
Data Source
AI summary
A system is described comprising a first controller configured to control a radial arm. The system further comprises a second controller configured to control a probe apparatus motor. The radial arm is configured to move a probe apparatus in a horizontal direction across a horizontal cross-section of a plasma plume generated by a thruster, in response to receiving a first control signal from the first controller. The probe apparatus motor is configured to move a probe, coupled to the probe apparatus, in a vertical direction across a vertical cross-section of the plasm plume, in response to receiving a second control signal from the second controller. And the probe is configured to detect an ion beam current density corresponding to the thruster, based at least in part on a movement of the probe apparatus in the horizontal direction and a movement of the probe in the vertical direction.