Miniaturized Plasma Thruster Using Permanent Magnets
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Solution Overview
Problem
Current plasma thrusters face challenges such as unreliable ignition, incomplete ionization, parasitic plasma jets, large size, high weight, and limited service life due to ion bombardment and propellant deposition, especially at low propellant gas pressures and flow rates, and require significant energy and complex electromagnetic coils.
Innovation Solution
A compact plasma thruster design using a magnetic field with specific intensity profiles and a microhollow cathode discharge for reliable ignition, combined with electromagnetic wave emission through the same injection nozzle to maximize ionization and energy absorption, reducing the discharge chamber length and utilizing permanent magnets for a more efficient and reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic coils are used to generate magnetic field for plasma ignition, then plasma ignition is achieved, but weight and space requirements increase significantly
Solution Approach 1:
The patent replaces electromagnetic coils with permanent magnets to generate the magnetic field required for plasma ignition. This substitution eliminates the need for powered electromagnetic coils, significantly reducing weight and power consumption while maintaining the magnetic field generation capability essential for ECR plasma ignition.
Solution Approach 2:
The permanent magnets provide a passive, self-sustaining magnetic field without requiring external power input. The magnetic field is generated inherently by the permanent magnets themselves, eliminating the need for powered coil systems and reducing overall system complexity and weight.
2Reliability
If discharge chamber length is increased to accommodate ECR resonance, then complete ionization is achieved, but thruster size increases
Solution Approach 1:
The patent changes the operating parameters by using permanent magnets to generate a stronger magnetic field, which allows ECR plasma ignition and complete ionization to occur in a much shorter discharge chamber. The parameter change in magnetic field generation method enables miniaturization while maintaining ionization effectiveness.
Solution Approach 2:
The patent concentrates the plasma ignition and ionization process in a localized region near the injection nozzle outlet by using permanent magnets to create a focused magnetic field. This dimensional concentration allows complete ionization to occur in a compact volume rather than requiring a long discharge chamber.
3Quantity of substance
If propellant gas pressure is reduced to minimize mass, then propellant consumption decreases, but plasma ignition reliability deteriorates
Solution Approach 1:
The use of permanent magnets instead of electromagnetic coils creates a more stable and intense magnetic field that enables reliable ECR plasma ignition even at low propellant gas pressures. This substitution maintains ignition reliability while allowing operation with minimal propellant mass.
4Productivity
If electromagnetic wave power is increased to improve energy yield, then ionization efficiency increases, but energy losses increase
Solution Approach 1:
The permanent magnet system reduces energy losses by eliminating the need for powered electromagnetic coils, which are subject to Joule heating losses. The passive permanent magnets generate the magnetic field without power consumption, improving overall energy yield while maintaining ionization efficiency.
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 solution achieves systematic and instantaneous ignition, complete ionization, reduced size, low weight, and high energy yield, with controlled thrust and specific impulse variation, and eliminates parasitic plasma jets and propellant deposition issues, enhancing the thruster's reliability and efficiency.
Implementation Method 1
a magnetic field generator capable of setting electrons of the propellant gas present in the discharge chamber in gyromagnetic rotation
Implementation Method 2
an electromagnetic wave generator capable of irradiating the propellant gas present in the discharge chamber by generating at least one electromagnetic wave the electric field of which has a right-hand circular polarization and a frequency equal to the frequency, fECR, of gyromagnetic resonance of the electrons of the propellant gas magnetized by said magnetic field generator
Implementation Method 3
a frequency equal to the frequency, fECR, of gyromagnetic resonance of the electrons of the propellant gas
Implementation Method 4
said injection means being produced from an electrically conductive material and electrically connected to the electromagnetic wave generator in order to emit the electromagnetic wave into the propellant gas at the outlet of the gas from said injection nozzle
Implementation Method 5
A compact plasma thruster design using a magnetic field with specific intensity profiles and a microhollow cathode discharge for reliable ignition
Data Source
AI summary
The invention, which relates to a miniaturizable plasma thruster, consists of: —igniting the plasma by microhollow cathode discharge close to the outlet and inside the means for injecting the propellant gas, said injection means being magnetic and comprising a tip at the downstream end thereof; —bringing the electrons of the magnetized plasma into gyromagnetic rotation, at the outlet end of said injection means; —sustaining the plasma by means of Electron Cyclotron Resonance (ECR), said injection means being metal and being used as an antenna for electromagnetic (EM) emission, the volume of ECR plasma at the outlet of said injection means being used as a resonant cavity of the EM wave; —accelerating the plasma in a magnetic nozzle by diamagnetic force, the ejected plasma being electrically neutral.