# Need help understanding off axis electromagnet field strength equation

• Jake110
In summary, the conversation is about an equation for the magnetic field strength of an electromagnet, which is provided on a website. The person tried using the equation up to the 8th power, but found that the field strength drastically increases instead of decreasing as expected. They are seeking help in understanding how to properly use the equation, and also inquire about the possibility of an equation for the field strength outside the central core.

#### Jake110

I have this equation for the magnetic field strength of an electromagnet but it’s in the form of multiple polynomials. Here is the page where they all are:

http://www.netdenizen.com/emagnet/offaxis/solenoidoffaxis.htm

since it gives values for e_8 and p_8 I tried using the main equation up to the 8th power but when I plotted the parallel distance against the field strength I found that it increases drastically to the point where at 5cm away the field strength is 1 Tesla (the strength I already know is B_0 which is the strength at the centre of the electromagnet and that’s only 0.03 Tesla)

So obviously the way I tried using it is wrong because the field strength should decrease the further away your measuring.

Can anyone help me figure out how to use this equation?

Read the page you linked carefully. Note that the polynomial represents approximately field strengths INSIDE the solenoid. As you have discovered, if you extrapolate polynomial approximations outside of the region it represents the values obtained become meaningless very fast,

damit, you wouldn't happen to know an equation for the field strength outside the central core would you?

## 1. What is an off-axis electromagnetic field?

An off-axis electromagnetic field refers to a magnetic field that is not aligned with the axis of an object or system. This can occur when the source of the field is not directly in line with the object, causing the field to be at an angle or off-center.

## 2. How is the strength of an off-axis electromagnetic field calculated?

The strength of an off-axis electromagnetic field can be calculated using the off-axis electromagnetic field strength equation. This equation takes into account the distance between the source of the field and the object, the angle of the field in relation to the object, and the strength of the field at its source.

## 3. Can the strength of an off-axis electromagnetic field be controlled?

Yes, the strength of an off-axis electromagnetic field can be controlled by adjusting the distance between the source of the field and the object, as well as the strength of the field at its source. Additionally, using shielding materials or altering the angle of the field can also affect its strength.

## 4. How does the strength of an off-axis electromagnetic field affect objects?

The strength of an off-axis electromagnetic field can have various effects on objects, depending on their composition and sensitivity to magnetic fields. Strong fields can cause objects to move or vibrate, while extremely strong fields can magnetize or demagnetize certain materials.

## 5. Are there any safety concerns related to off-axis electromagnetic fields?

Yes, there can be safety concerns related to off-axis electromagnetic fields, especially when dealing with strong fields or sensitive objects. These fields can potentially interfere with electronic devices, cause harm to living organisms, or disrupt certain processes. It is important to take proper precautions and understand the strength and effects of these fields when working with them.