Superconducting magnet with HTS wire

Click For Summary

Discussion Overview

The discussion revolves around the calculation of the magnetic field produced by a superconducting magnet constructed with high-temperature superconducting (HTS) wire, specifically in the context of a pancake or flat spiral coil geometry. Participants explore various mathematical models and methods relevant to this unique configuration, including both analytical and numerical approaches.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant describes the geometry of their superconducting magnet as a disk or racetrack coil and seeks guidance on the appropriate equations for calculating the magnetic field.
  • Another participant suggests that numerical methods, such as finite element methods (FEM) using software like COMSOL, are often necessary for complex geometries, as analytical methods may only apply to simpler shapes like long solenoids.
  • A participant identifies the coil type as a “pancake” or “flat spiral” coil and proposes a magnetic model based on a flat conductive disk with a sheet current, indicating that the inner to outer radius ratio is significant for model selection.
  • There is mention of using a first approximation of the magnetic field based on a single turn with the average radius, multiplied by the spiral current and number of turns.
  • Another participant encourages searching for existing literature on the magnetic field of pancake coils and asks for specific dimensions of the coil, including inner and outer radii, and whether an axial field is required.
  • The original poster shares their inner and outer radii measurements and expresses confidence in performing calculations, despite acknowledging limited math skills and a lack of familiarity with certain terms like "vector."

Areas of Agreement / Disagreement

Participants express a range of views on the appropriate methods for calculating the magnetic field, with some advocating for numerical methods while others suggest analytical approaches. The discussion remains unresolved regarding the best approach for the specific geometry of the coil.

Contextual Notes

Participants note the complexity of the geometry involved and the potential limitations of existing equations, particularly in relation to the specific configuration of the pancake coil. There is also a recognition of the need for further clarification on certain mathematical concepts.

Who May Find This Useful

This discussion may be useful for individuals interested in superconducting magnet design, particularly those working with pancake or flat spiral coils, as well as students seeking to understand the application of different mathematical models in electromagnetism.

MagnetDude
Messages
6
Reaction score
1
Hey guys, I am building a superconducting magnet. The wire I have is extremely thin, and is flat. To put it more into perceptive it has a width and height. When I wind it into a magnet, it is more like a disk coil, or racetrack coil. Because it has a different geometry than most other electromagnets, what equation would I use to calculate its magnetic field?

Most equations I have seen are a little something like this.

p=permeability
I=current
N=Number of turns
L=length of turn

The ones I have seen are PxNxI/L.

That goes for a solenoid mainly. The length of the coil I will make, if it were to be a disk, would be the Thickness of the wire times the number of turns, its width would have nothing relevant enough do with the calculation I would assume. After I find the turn density, what do I do? It is going to be a really weird magnet.
 
Engineering news on Phys.org
In most cases you end up having to use numerical methods, e.g. FEM using something like COMSOL.
Analytical methods rarely work unless you have a very simple geometry (e.g. a long solenoid(
 
The coil I think you are describing is called a “pancake” or a “flat spiral” coil.
The question as to which model to use really depends on the inner to outer radius ratio.

A simple magnetic model is a flat conductive disk with inner and outer radii that has a sheet current circulating, the sheet current is Nturns times the spiral current. That may give you a simple analytic solution.

A first approximation of the field could be that of a single turn with the average radius, multiplied by spiral current and number of turns.
 
f95toli said:
In most cases you end up having to use numerical methods, e.g. FEM using something like COMSOL.
Analytical methods rarely work unless you have a very simple geometry (e.g. a long solenoid(

F95toli: This is not a long solenoid though, this is a flat solenoid. To give you more of a perceptive of this wire, here is a link to the

Baluncore said:
The coil I think you are describing is called a “pancake” or a “flat spiral” coil.
The question as to which model to use really depends on the inner to outer radius ratio.

A simple magnetic model is a flat conductive disk with inner and outer radii that has a sheet current circulating, the sheet current is Nturns times the spiral current. That may give you a simple analytic solution.

A first approximation of the field could be that of a single turn with the average radius, multiplied by spiral current and number of turns.

I just spent about 30 minutes googling what you suggested, and that you were stating seemed to be right, but all the equations I am finding are for inductance. I am not finding anything that gives me the tesla strength of the magnetic field.
 
There are many users of pancake coils for SC magnets.
Google 'magnetic field of pancake coil' or 'magnetic field of spiral coil' and you will get examples of flat spiral design.

What are your inner and outer radii ?
Do you need axial field only ?
http://spectronet.de/portals/visqua/story_docs/vortraege_2009/090520_measurement/090520_tag1/090520_03_andris.pdf
 
Last edited:
Baluncore said:
There are many users of pancake coils for SC magnets.
Google 'magnetic field of pancake coil' or 'magnetic field of spiral coil' and you will get examples of flat spiral design.

What are your inner and outer radii ?
Do you need axial field only ?
http://spectronet.de/portals/visqua/story_docs/vortraege_2009/090520_measurement/090520_tag1/090520_03_andris.pdf
Sorry for the late reply. I am only trying to fine the field that would come out of the Z axis if that is what you mean by axial field. my inner radii is .7535 CM, my outer is going to be 1.691, with 75 turns of HTS wire. I think Ill be able to do all the calculations myself, My math skills might not be that sharp for I am still in high school. I have heard the term vector before, but I forgot what it is for.
 

Similar threads

  • · Replies 14 ·
Replies
14
Views
6K
  • · Replies 37 ·
2
Replies
37
Views
4K
  • · Replies 28 ·
Replies
28
Views
17K
Replies
76
Views
10K
  • · Replies 10 ·
Replies
10
Views
6K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
11
Views
4K
  • · Replies 26 ·
Replies
26
Views
3K
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K