External Discharge Hall Thruster Without Channel Walls
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Scaling down Hall thrusters to low power levels is challenging due to large surface area to volume ratios and physical limits to magnetic circuit miniaturization, leading to rapid erosion of thruster parts and reduced lifetime, with conventional designs suffering from power loss and efficiency issues due to plasma-wall interactions.
Innovation Solution
A Hall thruster design without discharge channel walls, magnetic core, or electromagnetic coils, utilizing permanent magnets to generate a strong radial magnetic field, allowing plasma discharge and acceleration to occur entirely in free space, reducing erosion and complexity while maintaining thrust efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional Hall thruster design with discharge channel walls and magnetic pole pieces is used, then magnetic field confinement and plasma generation are achieved, but rapid erosion of thruster parts occurs and lifetime is reduced
Solution Approach 1:
The patent removes the discharge channel walls and magnetic pole pieces from the thruster design, extracting the components that cause erosion. Plasma discharge occurs in free space rather than within a confined channel, eliminating the harmful plasma-wall interactions that lead to rapid erosion and reduced lifetime.
Solution Approach 2:
The invention converts the harmful effect of plasma-wall interactions into a beneficial configuration by allowing plasma to discharge externally. The erosion problem is transformed into a design advantage where the thruster components are protected from direct plasma exposure while maintaining effective thrust generation.
2Quantity of substance
If Hall thruster is scaled down to low power levels, then application to small/micro satellites is enabled, but surface area to volume ratio increases and magnetic circuit miniaturization reaches physical limits
Solution Approach 1:
The patent eliminates the complex magnetic circuit components including the magnetic core and pole pieces, replacing them with permanent magnets. This extraction of complex miniaturizable components enables scaling down to low power levels suitable for small/micro satellites without encountering the physical limits of magnetic circuit miniaturization.
Solution Approach 2:
The invention changes the magnetic field generation approach from electromagnetic coils requiring complex circuits to permanent magnets with fixed magnetic properties. This parameter change in the magnetic field source enables compact design at low power levels while maintaining adequate magnetic field strength for plasma confinement and acceleration.
3Force
If discharge channel walls and magnetic core are included, then magnetic field confinement is achieved, but dry mass and volume increase
Solution Approach 1:
The patent removes the heavy magnetic core and discharge channel walls, extracting the components that contribute significantly to dry mass. Magnetic field confinement is maintained through a simplified configuration using permanent magnets and external discharge geometry, reducing the weight of stationary components while preserving essential magnetic field functions.
4Force
If electromagnetic coils are used for magnetic field generation, then adjustable magnetic field strength is achieved, but device complexity and cost increase
Solution Approach 1:
The patent removes electromagnetic coils from the design, extracting the complex wound wire assemblies and associated power electronics. Permanent magnets provide the necessary magnetic field strength through their inherent magnetic properties, eliminating the need for complex electromagnetic coil systems while maintaining adequate field confinement and acceleration capabilities.
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
This design achieves a high lifetime with comparable thrust-to-power ratio and specific impulse, reduces dry mass and volume, and simplifies modeling and simulation, eliminating the need for costly lifetime tests and erosion research.
Implementation Method 1
utilizing permanent magnets to generate a strong radial magnetic field
Implementation Method 2
The invention uses permanent magnets enabling power reduction relative to thrusters with electromagnets
Implementation Method 3
Axial electric field crossed with the radial magnetic field forces the electrons to drift azimuthally enabling quasi-neutral plasma acceleration and thrust generation
Implementation Method 4
The entrapped electrons ionize the neutrals through collisions and gradually diffuse from the cathode to anode maintaining a strong axial electric field throughout the discharge channel
Data Source
AI summary
The invention is a Hall thruster that does not have any discharge channel, and magnetic pole piece. The Hall thruster utilizes permanent magnets to produce magnetic field with strong radial component in front of an annular anode, and expands propellant directly into vacuum through the anode acting also as a gas distributor. The invention reduces mass and complexity of conventional Hall thrusters, and offers a radical solution to discharge channel and magnetic pole piece erosion problem.