Hey Green Team, nice work.
A permanent magnet motor and an axial flux alternator are related to each other but they are different. Similar to the relationship between humans and apes. In some ways they look alike, but there are some major differences between the two.
Concerning the halbach array, that is an interesting arrangement that could be useful in the creation of a monopole that could be used to create a magnet motor. A magnet motor would be a self-powered motor. It would rotate by using only the power of the magnets. It is considered the holy grail of inventions that would solve the energy crisis in this planet. But the halbach array is not useful for an axial flux alternator.
For an axial flux alternator, those magnets in your picture are a bit too close to each other. If you put them closer than that, there would be a lot of flux leakage. Flux leakage is when the magnet flux jumps from one magnet to the magnet next to it. You don’t want that, that is wasted power.
Ideally, the magnet flux should flow through the coils to the magnet of opposite polarity on the rotor that is on the other side of the stator. When the flux goes through the coils, it produces voltage, that’s what you want.
You are doing OK. What you have there is a nice little system that you can use to learn from.
Keep us posted on your progress. If you have questions, just ask.
Ed