I Measuring change of magnetic field strengh over distance

[april7]

I have few cylindrical neodymium magnets of same diameter and different heights and different magnetic inductions in the geometric center of the magnetic pole surface. Knowing those values of magnetic induction, how can I measure what the induction is at a certain distance from that center?

For example height: 4 [mm] and induction: 0,263 [T]
What equation do I use to know what the induction is at distance of 4mm? I'm very much clueless about magnets and don't really know where to look.

 

[Vanadium 50]

Get a Hall probe.

Trying to measure the field with another magbet is difficult, as each pole responds differently, and what you will see is the difference in the field between the two. Converting that to a field is non-trivial.

 

[kuruman]

I have few cylindrical neodymium magnets of same diameter and different heights and different magnetic inductions in the geometric center of the magnetic pole surface. Knowing those values of magnetic induction, how can I measure what the induction is at a certain distance from that center?

For example height: 4 [mm] and induction: 0,263 [T]
What equation do I use to know what the induction is at distance of 4mm? I'm very much clueless about magnets and don't really know where to look.

Do you want to measure the magnetic field or calculate it? If you are "very much clueless about magnets" I suggest that you buy a magnetometer and measure it. There are apps for smartphones but I am not sure of their limitations for strong magnetic fields like yours. Also, bringing a neodymium magnet close to your smartphone might mess up its compass calibration or other "stuff".

 

[april7]

Do you want to measure the magnetic field or calculate it? If you are "very much clueless about magnets" I suggest that you buy a magnetometer and measure it. There are apps for smartphones but I am not sure of their limitations for strong magnetic fields like yours. Also, bringing a neodymium magnet close to your smartphone might mess up its compass calibration or other "stuff".

Yes, I haven't specified it but I need to calculate it

 

[Vanadium 50]

I need to calculate it

I'm very much clueless about magnets

Those two statements are mutually inconsistent.

What you want is very difficult and usually solved numerically. It is not for the clueless, I'm afraid,

 

[april7]

Those two statements are mutually inconsistent.

What you want is very difficult and usually solved numerically. It is not for the clueless, I'm afraid,

I'm doing my engineering thesis on superparamagnetic iron oxide nanoparticles (SPION) and I'm tasked with creating a model of magnetic pad we will use to stimulate particles with. I have to calculate which of few different neodymium magnets will give approximate value of 200 mT at distance of 4 mm. I want to know if I can calculate it and how I can do that without using programs.

 

[Vanadium 50]

Again, this is really hard. You don't even have adequately specified boundary conditions. As people have suggested, measure.

 

[april7]

well I used chatgpt, asked same question and was directed to online calculator and softwares that can calculate it
I've got my answer now so I guess thread can be closed

 

[kuruman]

Good luck.