Magnetic Solenoid with Compound Radius for Field Uniformity

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Solution Overview

Problem

Conventional magnetic solenoids with cylindrical configurations face challenges in generating a substantially uniform magnetic field, particularly near the ends and off-axis points, which is crucial for applications like NMR gyroscopes.

Innovation Solution

A magnetic solenoid design featuring a conductive coil with a radius defined by a compound equation that combines elliptical or circular functions for the central portion and exponential, parabolic, or hyperbolic functions for the ends, ensuring symmetry and uniformity along and off the central axis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a cylindrical configuration of the conductive coil is used, then the magnetic solenoid can be manufactured with simple geometry, but the magnetic field uniformity deteriorates near the ends and off-axis points

Engineering Contradiction:
Improvecoil geometry simplicityVSAvoidmagnetic field uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The conductive coil is designed with non-uniform turn density along its length, with higher turn density at the ends and lower turn density at the center. This local variation in coil structure compensates for the natural field non-uniformity, creating a substantially uniform magnetic field throughout the inner volume while maintaining manufacturability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The radius of the conductive coil is varied along its length according to a specific profile that increases at the ends and decreases at the center. This parameter change in the coil geometry transforms the magnetic field distribution from non-uniform (with a cylindrical coil) to substantially uniform throughout the inner volume

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the magnetic solenoid is designed for high field uniformity throughout the inner volume, then applications like NMR gyroscopes can be supported, but the solenoid size increases

Engineering Contradiction:
Improvemagnetic field uniformityVSAvoidsolenoid size
Core Design Contradiction:
Manufacturing precisionVSVolume of moving object

Solution Approach 1:

By concentrating the magnetic field generation capability where it is most needed (through non-uniform turn density), the design achieves high field uniformity in a compact volume, eliminating the need for oversized solenoids that would be required with uniform cylindrical coil designs

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The varying radius profile of the conductive coil optimizes the magnetic field distribution within a smaller overall volume, achieving the required uniformity without increasing solenoid dimensions

Inventive Principle:
Principle #35Parameter changes

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 design achieves magnetic field uniformity of better than five parts per million within a spherical volume, allowing for a significantly smaller solenoid size while maintaining high uniformity, and is applicable in various magnetic field applications.

Implementation Method 1

magnetic solenoids can be implemented to generate a magnetic field for a gyroscope, such as a nuclear magnetic resonance (NMR) gyroscope that is located within the inner volume of the magnetic solenoid, to induce precession of noble gas isotopes

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

magnetic solenoids can be implemented to generate a magnetic field for a gyroscope, such as a nuclear magnetic resonance (NMR) gyroscope that is located within the inner volume of the magnetic solenoid, to induce precession of noble gas isotopes

Methodology Applied
Scientific EffectPrecession: Precession

Data Source

PatentEP2392015B1Magnetic solenoid for generating a substantially uniform magnetic field
Publication Date: 2019.07.03 NORTHROP GRUMMAN GUIDANCE AND ELECTRONICS CO INC
  • EP2392015B1 patent drawingFigure 1
  • EP2392015B1 patent drawingFigure 2
  • EP2392015B1 patent drawingFigure 3

AI summary

One embodiment of the invention includes a magnetic solenoid. The magnetic solenoid includes an elongated sidewall that extends between spaced apart ends. The elongated sidewall can surround a central axis that extends longitudinally along the sidewall. The elongated sidewall can have a radius that is defined by a compound equation that varies the radius as a function of position along the central axis.