Particle beams

Actually, no.

The acceleration imparted on a particle in a gravitational field is a function of the strength of the field, and independent of the mass. To use the Newtonian approximation [easier to type, particularly from memory, and very few people can decipher tensor equations on sight] for a central-particle field, F=ma=Gm1m2/r^2 -> a=Gm2/r^2. While the form of a will differ in a sidewall, that doesn't change the fact that it's independent of the projectile mass.

Dilandu wrote:

Daryl wrote:Also with respect, 99.9% of light speed brings in massive tau effects. The particles would become much heavier, and harder to accellerate before that. Basically MC2=E.

And - harder to deviate from course, also. I.e. the defocusing effect of sidewalls would be greatly lessened.

Sorry, missed that. Forgot the free energy physics aspect of the Honorverse in general and gravitics in particular. In OTL it would require enormous energy input.

Daryl wrote:Also with respect, 99.9% of light speed brings in massive tau effects. The particles would become much heavier, and harder to accellerate before that. Basically MC2=E.

Dilandu wrote:
With all respect, 99,9% of lightspeed aren't as far away from 100% of lightspeed to make serious difference in tactical sence.

Okay.....but the thing doing the accelerating (at least in the case of a defensive sidewall or the edge of a wedge) is gravity - and the force exerted by gravity scales directly with mass - no matter the 'perceived' mass of a particle in a beam, the force it experiences from the sidewall wrenching it off course will be proportional.

The only way you get through without being deflected enough to miss is by crossing the sidewall in a short enough time period - so the difference in duration between crossing at 99% c and 100% c may be small in tactical terms, but in the kind of particle physics terms you need to consider for laser fire, nuclear detonations, radiation, etc, it may be all the time in the world.

locarno24 wrote:

Daryl wrote:Also with respect, 99.9% of light speed brings in massive tau effects. The particles would become much heavier, and harder to accellerate before that. Basically MC2=E.



Okay.....but the thing doing the accelerating (at least in the case of a defensive sidewall or the edge of a wedge) is gravity - and the force exerted by gravity scales directly with mass - no matter the 'perceived' mass of a particle in a beam, the force it experiences from the sidewall wrenching it off course will be proportional.

The only way you get through without being deflected enough to miss is by crossing the sidewall in a short enough time period - so the difference in duration between crossing at 99% c and 100% c may be small in tactical terms, but in the kind of particle physics terms you need to consider for laser fire, nuclear detonations, radiation, etc, it may be all the time in the world.

Except that sidewalls aren't infinitely powerful; if you hit them with enough force the generators overload and that section of sidewall goes down (at least temporarily)

We know (from the IFF armor essay) that an intermediate step between contact nukes and laserheads was the standoff sidewall "burner" where grav lenses focused the detonation of a nuke at the sidewall from modest standoff range. That wouldn't necessarily damage the ship but could blow out the sidewall leaving the target more vulnerable to follow up attacks.
But I don't know if Honorverse tech is up to generating a particle beam of sufficient power to do the same.

In fact, it probably is. Ship-mount lasers and grasers are almost certainly FELs, although TTBOMK this has never been confirmed, which means that they can accelerate electrons, at least, to GeV energies with ridiculous beam currents - and do it in something that fits inside the hull, to boot. In fact, given the physics, the power in the particle beams is 100-1000x the output of the weapons as radiation. Making the accelerator a pretty nasty weapon in its own right - except for 2 problems.

First, as noted, any massive particle is going to be strongly affected by the sidewalls. The more uniform the beam, the easier it will be to get it through, but these are not photons, and the beam isn't going to be [not is difficult to do, but not doable in principle] coherent, meaning that it will always disperse as it enters the side wall, not just bend the way photons do. Although, come to think of it, I would be designing the sidewalls with non-uniform fields so that there would be dispersion even with fully-coherent photon beams, an effect that will be amplified with particle beams.

Second, you have to used charged particles in the accelerator, and a charged beam will bloom as soon as it's out of the focusing fields. Probably useless as a weapon in less than 50,000km. There are a couple of ways of generating neutral beams, both of which involve inserting objects into the beam path. And those items will have to be replaced for every shot, require hyper-precise construction and placement, and even with that will seriously impair both beam energy and dispersion.

Jonathan_S wrote:Except that sidewalls aren't infinitely powerful; if you hit them with enough force the generators overload and that section of sidewall goes down (at least temporarily)

We know (from the IFF armor essay) that an intermediate step between contact nukes and laserheads was the standoff sidewall "burner" where grav lenses focused the detonation of a nuke at the sidewall from modest standoff range. That wouldn't necessarily damage the ship but could blow out the sidewall leaving the target more vulnerable to follow up attacks.
But I don't know if Honorverse tech is up to generating a particle beam of sufficient power to do the same.

Jonathan_S wrote:Except that sidewalls aren't infinitely powerful; if you hit them with enough force the generators overload and that section of sidewall goes down (at least temporarily).

Depends on the form of the energy. Pretty sure most missiles have far more kinetic energy than the energy released by the nuke going off, yet they don't knock out sidewalls.

Indeed, as I recall, it's more the sidewall penetrator that knocks down the sidewall in order to maximise the damage inflicted.

WLBjork wrote:

Jonathan_S wrote:Except that sidewalls aren't infinitely powerful; if you hit them with enough force the generators overload and that section of sidewall goes down (at least temporarily).

Depends on the form of the energy. Pretty sure most missiles have fare more kinetic energy than the energy released by the nuke going off, yet they don't knock out sidewalls.

Indeed, as I recall, it's more the sidewall penetrator that knocks down the sidewall in order to maximise the damage inflicted.

Hmm, good point. The one instance we saw of a missile actually hitting a sidewall was against Thunder of God.

That was 75 ton missiles impacting at 0.25c.
The Wolfram|Alpha kinetic energy calculator (that appears to account for relativistic effects) tells me that the missile would have had a kinetic energy of 2.005 * 10^20 joules.
That looks to be the equivalent of a roughly 48,000 megatons nuclear explosion (and the biggest nuke humans have set off yet was the 57 megaton Tsar Bomba in '61)!

So yeah, looked that that way it's weird that the grav focused blast of a nuke could drop a sidewall when the kinetic impact of the missile whose grav penetrator failed didn't. (Though maybe the wedge to sidewall interaction caused much of that energy to be dispersed and not directly strike the sidewall...)
Or maybe this is just how David wanted sidewalls to work; logic be damned

I think it's pretty clear that the implications of e=1/2m*v^2 didn't hit David until after book 4 was submitted.

If then.

I was vastly amused to discover that the first time he gave us enough details to integrate f dot dr for a trajectory - in AoV - it turned out that every ship in 8th Fleet would have had to fuse its own mass in hydrogen to get the energy for the approach to Enki, if all of it was coming from on-board power. It was around then that we first learned about the siphon effect

Major reason I get impatient with people who go on and on about some specific story element that's got their dander up. I've never seen any SFF story worth reading that looked better than 60-70% plausible anyway - often because I was too ignorant of the points where it fell flat on it's face to know that they weren't all that plausible. Which is why I run the numbers, have my chuckle, and move on.

kzt wrote:I think it's pretty clear that the implications of e=1/2m*v^2 didn't hit David until after book 4 was submitted.

Major reason I get impatient with people who go on and on about some specific story element that's got their dander up. I've never seen any SFF story worth reading that looked better than 60-70% plausible anyway - often because I was too ignorant of the points where it fell flat on it's face to know that they weren't all that plausible. Which is why I run the numbers, have my chuckle, and move on.

Yeah, that´s why it´s science FICTION rather than science, contemporary drama/action or something.

We can go on and on forever comparing how things would or could not work based on current knowledge, and it could easily be that some or most of it is effectively made useless by someone figuring out some kind of physics "cheat" tomorrow.




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With all respect, 99,9% of lightspeed aren't as far away from 100% of lightspeed to make serious difference in tactical sence.

I believe the point was that you´re not getting 99.9%. Frankly i doubt you can realistically get 90%.