It's kinda analogous to winding an electromagnet very carefully, but the stacked design (along with the holes) allows for easy and effective liquid cooling. It's a somewhat outside of the box thinking of magnet design.
I find it curious that I'm just learning about this now - I've never, ever have seen this kind of magnet construction discussed anywhere (and it is apparently a long-used technique)? I would expect such a design to be discussed in numerous areas (or even just mentioned), but I've never seen anything about it in popular press magazines or books, or anywhere else except now?
I wonder why that is? Is it only because such magnets are for very specialized use-cases, and fabricating one is outside the capability of most organizations, let alone individuals? Or are the use-cases such that almost no one else needs them (ultra-high current and high Tesla output) - and those that do would be in the circles that know about this construction?
Again, I just find it strange; I mean, in my life, I've found books and other sources that detail how to build STMs, CAT Scanners, and Radio Telescopes - but nothing of the nature of a magnet like this (and overall, it's fairly simple in concept and construction).
The magnets they talk about are 35 Tesla. I wonder what kinds of numbers you get from a fridge magnet, a bell wire+nail, or a crt or.. how many teslas (T) in a tesla (car)?
See, for instance: