Spherical Tokamak Negative Triangularity Plasma Confinement
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Solution Overview
Problem
Current spherical tokamaks face challenges in operating with negative triangularity due to construction complexity, software integration, and vertical stability issues, limiting their ability to achieve high-temperature, low-turbulence, and compact plasma confinement with reduced magnetic fields and installation space requirements.
Innovation Solution
A spherical tokamak reactor designed to operate with negative triangularity, featuring a chamber with divertor plates and poloidal field coil magnets that support both positive and negative triangularity configurations, along with a robotic mechanical structure and AI control for optimal plasma confinement and startup schemes like Double Null Merging, allowing for efficient plasma confinement and reduced magnetic field usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spherical tokamak is designed to operate with negative triangularity, then plasma confinement efficiency and turbulence reduction are improved, but construction complexity and software integration difficulty increase
Solution Approach 1:
The poloidal field coil magnets are designed to be movable and adjustable, allowing the tokamak to dynamically switch between positive and negative triangularity configurations. This enables the system to adapt its plasma shape for optimal confinement efficiency while managing construction complexity through a flexible, reconfigurable magnetic field system.
Solution Approach 2:
The system changes the triangularity parameter (δ) from positive to negative values to improve plasma confinement. By adjusting the poloidal field coil configurations and plasma current profiles, the tokamak can transition between different triangularity states, optimizing performance for specific operational phases such as startup versus steady-state operation.
2Stress or pressure
If spherical tokamak operates with negative triangularity, then magnetic field requirements are reduced, but vertical stability becomes more difficult to maintain
Solution Approach 1:
An AI-based control system continuously monitors plasma position and magnetic field configurations, providing real-time feedback to adjust poloidal field coil currents. This feedback mechanism compensates for the reduced magnetic field strength by dynamically optimizing the field distribution to maintain vertical stability during negative triangularity operation.
Solution Approach 2:
The system performs preliminary configuration of poloidal field coils and plasma current profiles before transitioning to negative triangularity mode. This preparatory action ensures that the magnetic field structure is pre-optimized to provide adequate vertical stability from the outset, preventing instability issues before they arise.
3Volume of stationary object
If spherical tokamak is designed for compact operation with reduced magnetic fields, then installation space requirements are reduced, but plasma confinement at high temperatures becomes more challenging
Solution Approach 1:
The tokamak employs advanced composite materials for the chamber walls and magnetic coil structures, enabling a more compact design with reduced installation space. These materials provide enhanced thermal and structural properties that allow the system to maintain high plasma temperatures despite the reduced size and lower magnetic field strength.
Solution Approach 2:
The system uses periodic pulsed heating and magnetic field adjustments to achieve and maintain high plasma temperatures in the compact configuration. By applying heating power in controlled pulses and periodically optimizing the magnetic confinement, the tokamak overcomes the limitations of reduced size and magnetic field strength.
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 design enables efficient plasma confinement with reduced turbulence and magnetic fields, achieving compact and cost-effective operation while maintaining high-temperature stability and efficient startup and steady-state conditions.
Implementation Method 1
said chamber comprises poloidal field coil magnets configured to support fusion plasma with both positive and negative triangularity
Implementation Method 2
During the tokamak discharges, it was observed that the vertical distension of the plasma and the creation of a 'D' shape could allow to obtain a double effect
Implementation Method 3
the divertor field coils guide the radially inner plasma separator leg towards the respective divertor plate
Implementation Method 4
the heating of the plasma was obtained by ohmic means, i.e. by resistive heating generated by the induced plasma current
Implementation Method 5
heating by means of an electron cyclotron, which is able to change the deposition of the heating on different regions of the plasma
Implementation Method 6
Fusion reactions are considered a great opportunity to generate abundant ecological and economically scalable energy for terrestrial use
Data Source
AI summary
A spherical-type tokamak, configured to operate with plasma in negative triangularity, includes a chamber for housing a plasma, and is configured so that, during operation, the plasma defines a profile having both in an upper region and in a lower region of said plasma, radially internal and external plasma separator legs. The chamber includes upper and lower regions for receiving the upper and lower plasma regions. The upper and/or lower regions of the chamber are equipped with at least one divertor. The at least one divertor includes a divertor plate and divertor field coils. The divertor field coils are configured to drive the radially inner and radially outer plasma separator legs towards the respective divertor plate. The at least one divertor includes an inlet which is located in an external support vessel in a radially outermost position with respect to a point of the respective region.