Antimatter, manipulated by magnetic fields, thus (as Tim B II notes), electricity.
Except instead of using antimatter to combine with matter and produce energy, we discover that antimatter in quantity produces anti-gravity, and beyond that we find new physics of antimatter. When iron atoms have their magnetic poles aligned they are all reinforced (not canceling each other) and create a useful magnetic field.
So once we have enough antimatter atoms of various elements, we discover something similar about one of them, a field that allows normal matter to "sink" into dark-space.
As Tumbislav notes, our space is continuous with and floats on darkspace. This approach can also explain the (IRL) dilemma of the missing antimatter in the universe; it is basically all in darkspace as antimatter. Like oil and water, they have separated, and although they can be mixed and were thoroughly mixed at creation, they naturally tend to separate into light-space and dark-space. As a result, the collective anti-gravity of anti-matter (anti-gravitons) in dark-space will repel photons, which is why it is dark.
Photons are their own anti-particle (maybe) but (hand-wavy) the anti-gravity keeps them out of dark-space, and if photons are emitted IN dark-space, they don't travel in a precisely straight line, they have a half-life: after a few light minutes they will "decay", vanishing from dark-space and emerging spontaneously in light-space. That's what the expanded quantum theory says, anyway, and to us in light space, this happens naturally so seldom we never observed it, or attributed it to experimental error or spontaneously formed photons from the quantum foam.
However, now that we can access dark-space and emit photons in it, we have verified that component of expanded quantum physics.
The matrix ripper field, like magnetism, can be controlled in power by physically manipulating the antimatter (say it is a specific element, like anti-Hassium). We can do that with strong magnetic fields. Just like we can use magnetic fields to levitate, spin, and move magnetic objects around. So I'd make this matrix-ripper field something we get by spinning anti-hassium at relativistic speeds (near light speed) using magnets (in a vacuum of course), and we can physically move spinning spheres of anti-hassium around to give shape to the matrix ripper field, and spin it faster or slower to control the depth in dark-space.
If our engines fail (they can be anti-matter engines too) then the anti-hassium sheds energy into the matrix ripper field, slows down, and the ship emerges from dark-space into light-space. Perhaps catastrophically if this is uncontrolled, into a planet, sun or black hole.
Hassium (HS, the normal version) is a silvery metal in the same column of the periodic table as Iron, Ruthenium and Osmium, all of which are metals with magnetic properties. Only about 100 atoms of Hassium have been formed in super colliders; and it has a half-life of about 10 seconds; but I'd hand-wave something that "stabilizes" it, or hand-wave a machine that produces a constant supply.
It will likely be centuries (to never) before we can perform actual chemistry on anti-matter and produce anti-atoms of anything but the lightest materials, so all of this is "can't prove me wrong" science.