The pinch-field generator operates on the same principle as a black hole.
Matter makes light bend. The mechanism isn’t really light bending, per-se, so much as space bending around it. So the light travels a straight line in curved space, and it only looks like it bends.
Well, it turns out mass and energy are really the same thing. This gave an engineer an idea. And his son the same idea. And in turn his twin daughters the same idea, and one of their sons the same idea, and his son the same idea, and so on for a dozen or so generations until one of the line of engineers finally succeeded, and vague speculations became ultra-secret, classified military projects. See, with a bit of trickery, energy can be made to distort space too. And by rerouting that energy, you can change the effect, in a manner impossible with ordinary matter.
Why you hitting yourself?
The basic idea is to create, preferably as far from your ship as possible, a grid of superconducting cables, then dump energy into them. Like, a lot of energy. Like, the-total-output-of-the-sun-for-a-year kind of energy. But, with Dyson spheres around a hundred or so stars, the first fully functional ship sporting a pinch-field generator was completed in the 19th year of the Human-Tassad war.
The first encounter is worthy of note. At 7550-12-12 04:07 EST, the Tassad battlecruiser opened fire with starboard laser batteries 45 through 97 at a range of 17 light-seconds and nearly zero relative velocity. The U.F.P. Dauntless, sensors tripping at the sudden heat flux, automatically deployed the pinch-field’s incomprehensible energy from the central core of the ship, out into the far distant material of the shield.
As the night watch in the Dauntless was thrown unceremoniously into null-G, to a distant observer, the Dauntless appeared to disappear in an instant. But look closely, and you could see that the area where the shield had been now appeared a reflection–a cosmic mirror.
In truth, what had happened was the light now bent through 180 degrees, while still traveling in a straight line. But, unlike any physical mirror, no fractional percentage of light was absorbed by any material. No weakness existed. In fact, any material object nearby, save the exquisitely balanced shield cables themselves, would be torn asunder by tidal forces almost instantly. Invulnerable.
The titanic blast from the 53 Tassad laser batteries came to bear on the pinch-field, and were promptly and utterly harmlessly rotated through twisted space, 180 degrees in heading. Thereupon, the fiery lasers of the Tassad battlecruiser demonstrated the meaning of that ageless playground taunt: “Why you hitting yourself?”
The Human-Tassad War ended tidily in the 20th year.