Plasma Accelerator Coil Winding for Mutual Inductance Reduction
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Solution Overview
Problem
Conventional plasma accelerators experience unstable current application and phase differences due to significant mutual inductance between coils, leading to inefficient plasma acceleration and operation instability.
Innovation Solution
The coils are wound in opposite directions and connected to each other, reducing mutual inductance and allowing for precise adjustment of current levels and phase differences, thereby simplifying the driving circuit and stabilizing the plasma acceleration process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coils are wound independently without connection, then each coil can be controlled individually, but mutual inductance between coils causes unstable current application and phase differences
Solution Approach 1:
The patent connects adjacent coils in series to form coil groups, merging multiple independent coils into unified operational units. This reduces the number of independent control channels from 6 to 3, minimizing mutual inductance effects while maintaining individual coil functionality through the series connection structure.
Solution Approach 2:
The patent segments the 6 coils into 3 coil groups (S1-S2, S3-S4, S5-T), where each group contains 2 adjacent coils connected in series. This segmentation reduces the total number of controlled entities and minimizes mutual inductance between groups while preserving the essential function of each coil.
2Measurement precision
If multiple independent currents are applied to each coil, then plasma generation is achieved, but current level and phase difference control becomes inaccurate
Solution Approach 1:
The patent combines the control of adjacent coils by connecting them in series, reducing the number of independent current sources from 6 to 3. This merging simplifies the driving circuit while improving current control precision by eliminating mutual inductance interference between independently controlled coils.
Solution Approach 2:
Each coil group functions as a unified control unit that can generate the required magnetic field while simplifying the overall system. The series-connected coil groups serve multiple purposes: reducing mutual inductance, simplifying control circuitry, and maintaining the ability to generate plasma through coordinated current application.
3Reliability
If coils are connected in series and wound in opposite directions, then mutual inductance is reduced and current control is improved, but coil winding complexity increases
Solution Approach 1:
The patent merges adjacent coils into series-connected groups wound in opposite directions. This approach reduces mutual inductance between groups while the opposite winding directions cancel out some magnetic field interactions, improving operational stability despite increased winding complexity.
Solution Approach 2:
The patent introduces asymmetry in the winding directions of adjacent coils within each series group. By winding coils in opposite directions, the magnetic fields partially cancel each other, reducing mutual inductance effects and improving current control stability, though requiring more complex winding procedures.
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 approach reduces mutual inductance between coils, enabling accurate current control and phase adjustment, which enhances plasma acceleration efficiency and stability, facilitating improved plasma flow and semiconductor wafer etching processes.
Implementation Method 1
The currents flowing through the coils T, S1, S2, S3, S4, and S5 generate a magnetic field in the plasma accelerator. The magnetic field generated in the plasma accelerator by the currents flowing through the coils T, S1, S2, S3, S4, and S5 induces a second current according to Maxwell induction equation, and the second current converts gas in the plasma accelerator into plasma.
Implementation Method 2
The magnetic field is generated by the currents and accelerates the plasma toward the exit. A magnetic pressure distribution is B2/2μ. Herein, B denotes a magnetic flux density and μ denotes a permeability.
Data Source
AI summary
A plasma accelerator is provided. The plasma accelerator includes a chamber having a closed top, an opened bottom and a lateral surface, a first coil section comprising a plurality of coils that are connected to one another in series and are wound around the lateral surface of the chamber in opposite directions, and a second coil section comprising a plurality of coils that are wound around the lateral surface of the chamber between coils of the first coil section in opposite directions. Accordingly, it is possible to make the mutual inductance between the coils small, to accurately adjust levels and phase differences of currents to be applied to the coils, and also to simplify the driving circuit.