Questionable Questing

Persimmon

With cold coupling, they'd exceed grasers in ability to hold a small spot size at long range. Threat range vs manouvering targets is thus light minutes, like other lightspeed weapons.

I think I'll do a omake/writeup on potential Aliceverse Particle Weapons sometime tomorrow. At the gym right now.

inverted_helix

That's very surprising to me, since atomic rockets article about particle beams suggested that their minimum beam angle was much worse than lasers and so would be shorter ranged.

magic9mushroom

What's cold coupling?

inverted_helix

Hmm interesting, read up on it a bit. I'm basically a layman, but it seems like cold coupling is basically using particles that will form molecules in flight. So a beam of hydrogen atoms that collect into H2 molecules in flight averaging their velocities and thereby reducing beam divergence.

inverted_helix

From my reading it seems like particle beams would basically force crafts to deploy plasma and magnetic shields at all sizes instead of just the PD laser and large graser realms, and that they'd wreck unprotected dust barriers allowing RKKV shots to hit the ships directly.

Persimmon

Cold beams are obtained by chilling the ion source and averaging their traverse velocities before feeding into the main accelerator. You can further reduce the temperature of the beam (and thus divergence) via molecular bonding, yes.

Persimmon

Laser-coupling is using an optical tweezer effect on a particle beam via laser to dramatically reduce divergence, an immense game changer. Most of Atomic Rockets was written pre-PROCSIMA, so I'm not surprised.

inverted_helix

So I read this article on the subject: http://toughsf.blogspot.com/2019/02/cold-laser-coupled-particle-beams.html

I think their penetration numbers rather implausible, I suspect it doesn't account for amount of energy bouncing back into space. But the overall explanation at least made sense to me.

inverted_helix

Overall it doesn't seem that plausible to get a particle beam close to lightspeed with this sort of mechanism either. It seems to get less efficient as speed rises because it's harder to maintain low enough divergence. So you're probably firing beams in the 0.1 to 0.5 c range. Which means that against a moving target your effective range is lower than an RKKV or graser.

inverted_helix

Against a stationary target it's better than grasers, but lesser than the hypothetically infinite range of RKKVs.

Either way though this would offer a much longer ranged option for ships too small to mount an RKKV than conventional mass drivers which tend closer to 0.01c.

inverted_helix

Since it's fundamentally normal particles just accelerated to high speed, then I think normal deflector shields should work on them as well as they would against a mass driver round with similar energy put into it. I think it likely penetrates armor better because the energy is more focused than a mass driver similar to an RKKV.

Persimmon

Laser power required to maintain optical tweezing rises with particle beam throughput/current, not particle energy. To be honest, PROCSIMA is so new we haven't even gotten the results from the first experiments yet.

Persimmon

But yes, I could see laser coupling requiring dramatically shorter -frequencies- as beam speed approaches C. Which would mean to get graser range you'd need a graser tier FEL, lol.