Years ago there was some hype around a theory that would supposedly allow for FTL. But I have since heard nothing of this.
Is anything happening with the theory? How would a magnetic field allow us alter spacial dimensions?
As far as I know, you can not alter space-time curvature with any realistic amount of magnetic field(you'd need a planck energy per planck length to rip the fabric, which is equivalent to a black hole anyway).
As for FTL, it brings up so many problems that it should not really exist in a universe obeying "casuality".
About Heim Theory,
Some scientists are so concerned with addressing some specific problems in physics that their resultant theory is in contrary with even every-day phenomena like F=ma or x=vt. They, of course, do not do this just to mess around, it is done to lead some other theories to a reasonable final theory. However, as far as I know, it was not Heim himself that tried to apply FTL travel to Heim theory, it was some other physicist who found a way to implement Heim theory in a way for it to allow FTL travel.
As a result,
-Heim theory is not really considered a valuable candidate for replacement of GR&QM. -The fact that it proposes FTL does not really mean much for us since it is so lackluster in so many aspects that you can't really trust it. -A stronger magnetic field would not really allow for much alteration in any spatial dimension. It would just tear you apart because of diamagnetism of water and strip the info out of your credit cards at a longer distance. Incredibly strong magnetic fields exist near magnetars and FTL phenomena would have been observed near magnetars if there were such a condition.