Is the magnetic field inside a solenoid stronger near the border?

[Rafikix]

I was reading some papers about calculating the magnetic field produced by a coil using the biot savart law and I saw some graphs that caught my attention.

This one from a paper from Ravaud, et al. Titled "Calculation of the Magnetic Field Created by a Thick Coil". I saw similar graphs in other articles too.

And this one from the wikipedia entry for solenoids.

They seem to indicate that the magnetic field gets stronger near the border, whereas from my intuition I thought they were stronger in the center.
I also did a simulation in python using the biot savart law and the formula from Ravaud's paper and the plot looked like the wikipedia's one, with the magnetic field stronger nearing the border with that triangular shape.

How do I explain this?

 

[Vanadium 50]

By "border" you mean coils? Yes, the field is strong near the coils.

 

[hutchphd]

The center of the coil is at r=0...that would be about a foot off the side of my monitor. This is in a tenth inch thick wire turn I beleive.

 

[Keith_McClary]

whereas from my intuition I thought they were stronger in the center.

My intuition is that the coils are the source and the field always gets weaker as you go away from them. I will try to think of a proof.

 

[hutchphd]

For a long straight wire the field falls off as 1/r. If you get close enough everything is flat...
You mean coil center or wire center ?

 

[Dale]

They seem to indicate that the magnetic field gets stronger near the border, whereas from my intuition I thought they were stronger in the center.

The field is most uniform in the center. It is strongest near the coil.

 

[A.T.]

... from my intuition I thought they were stronger in the center...

To test intuitions consider extreme cases: Increase the radius of the coil towards infinity while keeping its axial length constant. Does your intuition still say that the field will be strongest in the middle, far far away from the conducting wire loop?