Current Loop equivalent to Earth's Magnetic Field

In summary, the Earth's magnetic field at the equator is approximately 31 microT and at 50 degrees latitude it is about 58 microT. To approximate this field with a superconducting belt placed around the equator, it is estimated that it would need to carry around 20MA of current, although this number may be affected by the Earth's iron content. The US/UK World Magnetic Model for 2010-2015 provides detailed data for these calculations, but a simpler estimate may be off by a factor of 2. Further calculations using the B=uI/2R formula are needed, but this assumes a constant permeability which may not apply to a solid sphere in a vacuum.
  • #1
.Scott
Science Advisor
Homework Helper
3,472
1,587
I'm trying to get a feel for the overall magnitude of the Earth's magnetic field.

If I placed a superconducting belt around the Earth magnetic equator, how much current would that loop have to carry to approximate the Earth magnetic field?

Currently, the field at the equator is about 31 microT and at 50 degrees latitude is about 58 microT.

If I replace the Earth with a vacuum, it looks like I would need on the order of 20MA - but I have no confidence in that estimate. It looks to me as though the Earth's iron content might bring this number down.
 
Physics news on Phys.org
  • #3
Bobbywhy said:
This document appears to have all the necessary data to answer your questions:

The US/UK World Magnetic Model for 2010-2015
http://www.ngdc.noaa.gov/geomag/WMM/data/WMM2010/WMM2010_Report.pdf

That all very incredibly detailed - but I would settle for and answer that's off by a factor of 2.
I have the basic data and the B=uI/2R formula (for the center of a current ring). What I don't have is any experience calculating magnetic fields directly from currents - so I am very uncertain of my computations.

Also, the B=uI/2R is for the center of a current ring, not on the surface of a sphere girdled by a current ring - so I don't have a direct comparison. The B=uI/2R also assumes a constant permeability (u) which is not the case of a solid sphere hanging in a vacuum.
 

1. What is a Current Loop equivalent to Earth's Magnetic Field?

A Current Loop equivalent to Earth's Magnetic Field is a model used by scientists to describe the strength and direction of the magnetic field surrounding a current-carrying loop. This model is based on the principle that a current-carrying loop generates a magnetic field that is similar to the Earth's magnetic field.

2. How is the Current Loop equivalent to Earth's Magnetic Field calculated?

The strength of the Current Loop equivalent to Earth's Magnetic Field is calculated by multiplying the current passing through the loop by the number of turns in the loop and dividing it by the distance from the loop. The direction of the field is determined by the right-hand rule, where the fingers of the right hand point in the direction of the current and the thumb points in the direction of the magnetic field.

3. What is the purpose of using the Current Loop equivalent to Earth's Magnetic Field?

The Current Loop equivalent to Earth's Magnetic Field is used to simplify calculations and understand the behavior of magnetic fields. It also provides a way to visualize the strength and direction of magnetic fields in a current-carrying loop.

4. Can the Current Loop equivalent to Earth's Magnetic Field be used for any current-carrying loop?

Yes, the Current Loop equivalent to Earth's Magnetic Field can be used for any current-carrying loop, as long as the loop is small compared to the distance from the loop and the current is constant. This model is not applicable for larger and more complex systems.

5. How does the Current Loop equivalent to Earth's Magnetic Field affect the behavior of a compass?

The Current Loop equivalent to Earth's Magnetic Field can cause a compass needle to align with the direction of the magnetic field in the loop. This can be seen in devices such as galvanometers and electromagnets, where the magnetic field from the current loop can affect the movement of the needle or the strength of the magnetic field in the electromagnet.

Similar threads

I Work Done in Changing Shape of Current Carrying Loop
    • Electromagnetism
Replies
5
Views
851
I Is the magnetic field from this current rotationally symmetric?
    • Electromagnetism
Replies
12
Views
750
I Origin of the Earth's magnetic field
    • Electromagnetism
Replies
8
Views
1K
I Resulting magnetic field due to the passage of an AC current
    • Electromagnetism
Replies
27
Views
1K
I Effect of Fringe Fields for a Bending (Dipole) Magnet on Field Integral?
    • Electromagnetism
Replies
0
Views
104
B Calculating Force on an Iron Object with Magnetic Field
    • Electromagnetism
Replies
21
Views
1K
Magnetic field on a loop due to another loop
    • Electromagnetism
Replies
2
Views
15K
I Simple electromagnetic wave including delay
    • Electromagnetism
Replies
2
Views
362
Force acting on a current carrying conductor within a magnetic field
    • Electromagnetism
Replies
2
Views
822
Faraday's Law with Zero Resistance Current Loop
    • Electromagnetism
Replies
2
Views
6K

Hot Threads

Recent Insights

Back
Top