Top Surface Wave Antenna Layout for Tokamak Core Power Absorption
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Solution Overview
Problem
The density limit in current driving of low-hybrid wave external antennas in small Tokamaks restricts the effective absorption of power in the plasma core region, necessitating a top surface wave antenna design to complement peripheral antennas.
Innovation Solution
A top surface wave antenna for a spherical Tokamak is designed with a feedback waveguide, a brim, sub-waveguides, and a metal base, arranged in a compact sawtooth pattern to enhance microwave absorption and stability, acting as a supplementary antenna to peripheral ones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If low power external antenna is used for non-inductive current driving, then current driving capability is improved, but power absorption in core region deteriorates due to density limit
Solution Approach 1:
The antenna system is segmented into two distinct parts: external antennas for current driving and a top surface wave antenna for core region power absorption. This segmentation allows each antenna type to specialize in its optimal function, with the top antenna specifically designed to penetrate the density limit and deliver power to the core region where external antennas cannot effectively reach.
Solution Approach 2:
The top surface wave antenna acts as an intermediary component that bridges the gap between external power sources and the core plasma region. It receives microwave power and converts it into surface waves that propagate along the plasma boundary, effectively mediating energy transfer into the core region without being directly exposed to the density limit constraints affecting external antennas.
2Use of energy by moving object
If top surface wave antenna is designed to promote power absorption in core region, then power absorption capability is improved, but device complexity increases
Solution Approach 1:
The antenna structure merges multiple functional components into a unified design: the feed waveguide, brim structure, and array of radiating elements are integrated into a single top surface wave antenna assembly. This merging reduces the need for separate complex systems while achieving both power absorption and structural stability through a consolidated design approach.
Solution Approach 2:
The antenna transitions from a two-dimensional external antenna configuration to a three-dimensional top-mounted structure with vertical penetration into the plasma. By adding the vertical dimension and utilizing the top surface of the tokamak, the antenna achieves direct access to the core region without increasing horizontal complexity, effectively using spatial dimensionality to simplify the overall system architecture.
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 top surface wave antenna achieves stable performance and excellent testing results, effectively promoting power absorption in the plasma core, thereby overcoming the density limit issues and meeting experimental requirements.
Implementation Method 1
The lower end of the feed waveguide is connected to one end of the metal base, and one side of the feed waveguide is connected to the brim
Implementation Method 2
Low-hybrid wave current driving is one of the most effective Tokamak non-inductive current driving methods recognized
Implementation Method 3
A top surface wave antenna of a spherical Tokamak comprises a feedback waveguide, a brim, sub-waveguides, and a metal base
Data Source
AI summary
Disclosed is a top surface wave antenna of a spherical Tokamak, comprising a feedback waveguide, a brim, sub-waveguides, and a metal base. The lower end of the feed waveguide is connected to one end of the metal base, and one side of the feed waveguide is connected to the brim. The brim is towards a length direction of the metal base. A plurality of sub-waveguides are arranged on the metal base at equal intervals, the tops of the sub-waveguides are not higher than the height of the metal base, and the sub-waveguides are arranged in a rising line trend. The feed waveguide serves as a microwave input port. The top surface wave antenna of the spherical Tokamak is mainly used in a high-power Tokamak system and acts on the low-hybrid wave current driving together with an external antenna so as to obtain a better effect.