Tunable Neutral Beam Injectors for FRC Plasma Stability
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Solution Overview
Problem
Conventional Field Reversed Configuration (FRC) systems face challenges in maintaining stability and confinement of plasma due to convective losses and the need for external multipoles to control rotational instabilities, which can lead to fast particle losses, especially in advanced hybrid FRCs with kinetic and thermal plasma combinations.
Innovation Solution
The system employs a combination of neutral beam injectors with tunable beam energy capabilities, axial plasma guns, mirror plugs, and advanced magnetic field control using quasi-dc coils and saddle coils to stabilize the FRC plasma in both radial and axial directions, and to maintain a high-performance FRC regime with improved particle, energy, and flux confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional FRC systems use external multipoles to control rotational instabilities, then stability of the plasma is improved, but fast particle losses increase
Solution Approach 1:
The patent removes external multipole fields from the system and replaces them with an internally generated magnetic field structure. The FRC plasma itself generates the necessary magnetic field configuration through its current, eliminating the need for external multipoles that cause fast particle losses while maintaining rotational instability control.
Solution Approach 2:
The FRC plasma becomes self-sustaining by generating its own magnetic field structure through internal currents. The plasma current creates the magnetic field that provides rotational stability, eliminating dependence on external multipole systems that cause particle losses.
2Reliability
If conventional FRC systems use high magnetic fields to improve confinement, then particle and energy confinement are improved, but device complexity and operational costs increase
Solution Approach 1:
The patent changes the magnetic field strength parameter from high to low, operating the FRC in a regime with reduced magnetic fields. This is compensated by optimizing other parameters such as plasma current density and configuration geometry to maintain confinement performance without requiring complex high-field magnet systems.
3Reliability
If conventional FRC systems use larger machine sizes to improve confinement, then particle and energy confinement are improved, but device complexity and operational costs increase
Solution Approach 1:
The patent optimizes the plasma configuration parameters including aspect ratio, minor radius, and current distribution to achieve superior confinement in a compact geometry. By carefully controlling these parameters, the system achieves high confinement performance without requiring large machine dimensions.
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 significantly enhances the confinement time of FRCs by over a factor of 5 compared to conventional systems, allowing for longer plasma sustainment and higher energy operation without the need for high magnetic fields or large machine sizes, reducing operational costs and engineering complexity.
Implementation Method 1
fast (H) neutrals are injected from neutral beam injectors to provide heating and current drive as well as to develop fast particle pressure
Implementation Method 2
external magnetic fields of about 0.1 T, plasma densities around 5×10 19 m−3, and temperatures in the range 10-100 eV
Implementation Method 3
The present FRC system 10 employs sets of mirror coils 420, 430, and 444 as shown in Figures 2 and 3
Implementation Method 4
The Field Reversed Configuration (FRC) belongs to the class of magnetic plasma confinement topologies known as compact toroids (CT). It exhibits predominantly poloidal magnetic fields and possesses zero or small self-generated toroidal fields
Implementation Method 5
two separate theta-pinches at opposite ends of a confinement chamber simultaneously generate two plasmoids and accelerate the plasmoids toward each other at high speed; they then collide at the center of the confinement chamber and merge to form a compound FRC
Data Source
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AI summary
Systems and methods that facilitate forming and maintaining FRCs with superior stability as well as particle, energy and flux confinement and, more particularly, systems and methods that facilitate forming and maintaining FRCs with elevated system energies and improved sustainment utilizing neutral beam injectors with tunable beam energy capabilities.