Is There a More Accurate Equation for the Magnetic Moment of a Solenoid?

In summary, there are discussions about finding an equation that accurately describes the magnetic moment of a solenoid without using the number of turns as an input. The standard formula for the B field at the middle of a long solenoid has a dependence on the number of turns, but it is suggested to use a dipole equation instead. However, there is a desire for a better approximation, as a solenoid only becomes like a dipole at infinity. The B field on the axis at one end of a solenoid is 1/2 of what is given by the standard formula and the magnetic moment can be calculated using the equation m=BL/4pi in Gaussian units. Some confusion arises due to the missing cross-sectional
  • #1
Kydharis
4
0
Does anyone have an equation that describes the magnetic moment of a solenoid that does not actually use number of turns as an input?

I'm trying to validate a solenoid I have made with something like 11000 turns, but I'm not sure how accurate my number of turns in, so I need a second input that I can validate through testing (In this case, I can measure the magnetic flux at the poles of the solenoid).

I'm told that using a dipole equation for it is a decent approximation, but I'm really looking for a better approximation than that, since ideally a solenoid only becomes like a dipole at infinity.
 
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  • #2
The B field on the axis at one end of a solenoid is 1/2 what is given by the standard formula for the B field at the middle of a long solenoid.
 
  • #3
Yes, but unfortunately the standard formula for the B field of a long solenoid has a
dependence on N (turns).

I actually can measure B of my solenoid - its the magnetic moment I'm concerned about. I want to use the B field I measured to get a magnetic moment.
 
  • #4
In Gaussian units, the magnetic moment of a solenoid of length L with a field B at its center is m=BL/4pi.
 
  • #5
I left out the cross-sectional area of the solenoid.
The mag moment should be m=BAL/4pi.
 
  • #6
The units on that equation are a little weird. Right now, BAL/4pi is Tm^2 (or gauss*M^2). In my experience, magnetic moment is usually given in Am^2. I think the missing link is the magnetic constant - but adding it in with the 4pi leaves us with Am^3.
 

Related to Is There a More Accurate Equation for the Magnetic Moment of a Solenoid?

What is the magnetic moment of a solenoid?

The magnetic moment of a solenoid is a measure of the strength of its magnetic field. It is defined as the product of the number of turns in the solenoid, the current passing through it, and the area enclosed by the solenoid.

How is the magnetic moment of a solenoid calculated?

The magnetic moment of a solenoid is calculated by multiplying the number of turns in the solenoid by the current passing through it and the area enclosed by the solenoid. This can be represented by the equation M = NIA, where M is the magnetic moment, N is the number of turns, I is the current, and A is the area.

What factors affect the magnetic moment of a solenoid?

The magnetic moment of a solenoid is affected by the number of turns, the current passing through it, and the area enclosed by the solenoid. Additionally, the type of material the solenoid is made of can also affect its magnetic moment.

What is the unit of measurement for magnetic moment?

The unit of measurement for magnetic moment is the ampere-meter squared (A⋅m²) in the SI system. In the CGS system, it is measured in ergs per gauss (erg/G).

What is the significance of the magnetic moment of a solenoid?

The magnetic moment of a solenoid is significant because it determines the strength of its magnetic field. This is important in various applications such as electromagnets, electric motors, and generators. It also plays a role in understanding the behavior of magnetic materials.

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