Hi @hcf,
I am not really a fan of “North-pole only” (and sometimes I have heard “South-pole-only”) admonitions. I think these all come from, as you say, “the usual sources”. To me these claims have a certain distinctive whiff. They usually spiral off into indecipherable pseudo-scientific jargon, but on occasion when they are coherent enough, I often find myself saying “that’s definitely not how magnetism works”. So, I find these things to have very low (essentially zero) credibility, and since life has limited time, I do not invest any time trying to chase down, decipher, prove, disprove, or emulate anything related to these claims.
However, I might very well be wrong. You are a highly intelligent person, and if you decide to chase these things down, then I would be very interested to hear what you find. I do not know what secret special technical details (or imagined details) any of my products have as relates to this specific application such as edge effects or magnetic field dispersion, or anything like that, but you can get unipolar magnetic pulses as you suggest, by using specific “unipolar” pulse modes.
Unfortunately, I can not say exactly when or which mode will provide the desired “north” versus “south” pole, because ICES coils can be wound either way on our devices**, so for any specific pulse generator + one coil of a specific set of coils (the other coil in the pair will be opposite), you would need to check and verify the magnetic polarity during any of the unipolar pulse modes. For this you will probably need to use a high-speed Hall effect sensor and an o-scope (that’s how I do it).
So, it is definitely possible to do, and I would certainly want to hear the results anyone has to share if they go to the trouble to make the necessary measurements.
** Why do I not control for individual coil polarity as indicated by the bumpy sides of each of the coils? Because symmetry is assumed between N and S pulses, and there is therefore no need to control it. Could I control it? Yes, which would approximately double the cost of coils, with no benefit to customers unless they wanted to do what you are asking about. For reference, I have had one other person ask me about this several years ago. So, this specific feature is of interest to about 0.04% of people who use ICES-PEMF technology. So, the extra cost and effort is not justified IMO.