This core is a MetGlas PowerLite Amorphous Alloy taped core.
AMCC-80 and 6 modified Metglas bobbins made for the size 80 core.
It may be just the minimal size to provide an experiment, anything smaller gets hard to work with area and bobbins.
The core is vey important for this type of transformer.
From what I understand your standard laminate core will most likely not produce a decent result.
Its very important to tune to the cores resonant point.
Naudin has excellent M.E.G. pages:
http://jnaudin.free.fr/meg/megv21.htmThis is a great place to start to understand this technology.
M.E.G. Motionless Electromagnetic Generator. Also known as Flux Switched Transformer.
Picture of core shaving fell off while winding outer core bobbin. Ultra thin material 23um.