HTS Tape C-Angle Orientation in Tokamak Central Column
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Solution Overview
Problem
The construction of toroidal field coils using high temperature superconducting (HTS) tapes faces challenges in aligning the c-axes of the HTS tapes with the magnetic field, leading to either excessive number of coils or reduced critical current due to misalignment, especially in wound coils where uniform HTS distribution is required.
Innovation Solution
The use of multiple types of HTS tapes with different c-angles, strategically arranged in segments of the central column to optimize alignment with the magnetic field, allowing for fewer but more evenly distributed return limbs and improved critical current uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uniform HTS tapes are used in wound coils, then the coil structure is simple, but the critical current is reduced due to misalignment with the magnetic field
Solution Approach 1:
The patent applies local quality by using HTS tapes with different c-angles in different regions of the central column. Specifically, tapes with different c-angles (e.g., 0°, 45°, 90°) are strategically positioned at different angular positions around the central column to match the local magnetic field orientation, ensuring optimal alignment and critical current in each region while maintaining overall structural simplicity
Solution Approach 2:
The central column is divided into multiple segments, each containing HTS tapes with specific c-angles optimized for the local magnetic field conditions. This segmentation allows each region to be independently optimized for critical current while the overall coil structure remains relatively simple and modular
2Reliability
If HTS tapes are aligned with the magnetic field to maximize critical current, then the critical current is improved, but the number of return limbs increases
Solution Approach 1:
Instead of uniformly aligning all tapes, the patent uses local quality by applying different c-angle orientations only where needed. Tapes with specific c-angles are placed in regions where the magnetic field requires that orientation, while other regions use different orientations, thereby achieving optimal critical current without requiring additional return limbs for each orientation change
3Reliability
If HTS tapes with different c-angles are used, then the alignment with magnetic field is improved, but the manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into manageable sections, with each segment containing tapes of a specific c-angle. This allows for standardized manufacturing of each segment type, which can then be assembled into the complete central column, reducing overall manufacturing complexity despite using multiple c-angle variations
Solution Approach 2:
HTS tapes with different c-angles are pre-manufactured and prepared in advance as standardized components. This preliminary action allows for optimized manufacturing of each tape type independently, which are then assembled into the final structure, simplifying the overall manufacturing process while maintaining alignment optimization
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 the number of return limbs and enhances the critical current by aligning HTS tapes effectively with the magnetic field, improving the uniformity and efficiency of the toroidal field coil, while allowing for easier assembly and reduced heat loads.
Implementation Method 1
toroidal field coil for a tokamak plasma chamber... comprising a central column... HTS tapes
Implementation Method 2
high temperature superconductors (HTS)... critical temperature (the temperature above which the material cannot be superconducting
Data Source
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AI summary
An HTS assembly for use in a toroidal field coil having a central column is described. The HTS assembly comprises a plurality of parallel arrays of HTS tapes arranged to pass through the central column, each array comprising a plurality of HTS tapes arranged such that c-axes of all tapes in an array are parallel to each other, and such that planes of the HTS layers of the HTS tapes are perpendicular to a first radius of the central column. Each HTS tape has a c-angle which is an angle between a perpendicular to a plane of an HTS layer of the HTS tape and the c-axis of the tape. The plurality of arrays comprises first and second sets of arrays. Each array within the first set of arrays comprises HTS tapes of a first type having a first c-angle, and each array within the second set of arrays comprises HTS tapes of a second type having a second c-angle which is greater than the first c-angle. The first set of arrays are arranged closer to the first radius than the second set of arrays.