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[Rosen_Ritter_1]

I'm not sure what the point of the arguement here is


Increasing the rail guns energy on impact isn't that big of a deal, since they already pretty much oblitorate anything they manage to hit. And increasing velocity doesn't help that much against Loroi/Umiak opponents. The ranges they fight would make a doubling or even tripling of rail gun speed not much more useful.

[BattleRaptor]

The argument is based on some people missreading what I wrote, then attempting to argue outsider railgun specifics as if they had access to real world outsider tests in response to a statement of fact, instead of simply admitting they fracked up.

Rosen its a question of species evoloution.
You invent weapons that can kill your enemy before he can kill you, its a constant and continued advancement thoughout history.

Two terran ships with equal tech.
One that can fire a 100kg at 12kms and one that can fire a 200kg at 6kms will result in a kill rate that greatly favours the ship with the faster and hence longer/more accurate rounds.

Not only do you have longer range but you can carry more ammo.

Modern Rifle saw this exact thing happen, they went from heavy slow rounds to faster lighter rounds yet maintained the same or more energy.
and allowed soldiers to carry twice the ammo for the same weight.

[elizibar]

The argument is based on some people missreading what I wrote, then attempting to argue outsider railgun specifics as if they had access to real world outsider tests in response to a statement of fact, instead of simply admitting they fracked up.

Rosen its a question of species evoloution.
You invent weapons that can kill your enemy before he can kill you, its a constant and continued advancement thoughout history.

Two terran ships with equal tech.
One that can fire a 100kg at 12kms and one that can fire a 200kg at 6kms will result in a kill rate that greatly favours the ship with the faster and hence longer/more accurate rounds.

Not only do you have longer range but you can carry more ammo.

Modern Rifle saw this exact thing happen, they went from heavy slow rounds to faster lighter rounds yet maintained the same or more energy.
and allowed soldiers to carry twice the ammo for the same weight.

Assuming you have the practical materials technology to build the former railgun.

[fredgiblet]

The argument is based on some people missreading what I wrote, then attempting to argue outsider railgun specifics as if they had access to real world outsider tests in response to a statement of fact, instead of simply admitting they fracked up.

I very much wonder what thread you've been reading.

[Voitan]

It sounds like people are expecting humanity to be the hero of the story, rather than Alex.

Then check your ears, no one is saying humanity is going to make a difference in the war effort in the story.

It's been known for a while Arioch said such development is beyond the story in Outsider currently.

Everyone here is just speculating on what could happen given enough time.

One's also got to also consider then, that Loroi society in the next few decades is going to also be radically more different than it was centuries prior. Before the war Loroi society was majority centennials. War casualties and lifting of breeding restrictions has resulted in a massive demographic shift where there are now young than old. Even more dramatically, the newest generation didn't grow up under relatively assured Loroi dominance. They grew up in the middle of an apocalyptic war for survival challenging everything about Loroi society. You can't presume that development trends from the last half millennium will stick with these new war generations.

Maybe humanity could have outpaced the complacent previous generation over time. But what about this new one that's grown up knowing nothing but war? Who might not pay much heed to the cultural barriers of communication since they interfere in weapons R&D. Who might never go back to the old breeding restrictions and want to expand Loroi numbers as much as possible.


And you know what? I like that. I like having a situation where humanities position feels precarious. Where we CAN'T just jump ahead of everything by authorial fiat. Where we survive by adjusting to the situation and paying attention to the nitty gritty details.

Me too, I like the possible cultural upheaval that could change both societies.

Heck, what if Earth gets a bunch of expat Loroi immigrants? Probably not going to happen in the story, but surely listel castes will take trips to further study the humans in their environment.

[manticore7]

a Loroi among humans, I've always loved those human through alien eyes stories. though I think the Loroi would only be intrested in gathering tactical on humans.

[Voitan]

though I think the Loroi would only be intrested in gathering tactical on humans.

Sure, until they got distracted by chocolate.

SpoilerShow

And realize that humans consume the poisonous things in the galaxy, egads!

[manticore7]

behold our chocolate resistant bodies, and dispair!

[bunnyboy]

200 kg is peashooter, and you just throw them around.


700 kg is better to have around just being sure.


And 2300 kg makes good bang for surgical strikes.


This is how military think even if future.

[dfacto]

Their current record is 33 MJ, apparently with a 10.4 kg 2.5 km/s shot.

Which is why I doubt the best we can do in another 150 years is 3 GJ, 200kg and 6 km/s

Traditional artillery went from barely being able to dent a stone wall to blasting through a foot of hardened steel in a matter of 700 years, and that's with a clear limitation due to the use of chemical propellants and lack of any industrialization or widespread scientific research.

I'd be shocked if EM tech didn't progress very very rapidly once the barrel ablation/alignment issues are solved.

[Mjolnir]

Their current record is 33 MJ, apparently with a 10.4 kg 2.5 km/s shot.

Which is why I doubt the best we can do in another 150 years is 3 GJ, 200kg and 6 km/s

Traditional artillery went from barely being able to dent a stone wall to blasting through a foot of hardened steel in a matter of 700 years, and that's with a clear limitation due to the use of chemical propellants and lack of any industrialization or widespread scientific research.

I'd be shocked if EM tech didn't progress very very rapidly once the barrel ablation/alignment issues are solved.

Ablation is only an issue for deployment as a working weapon, not for achieving a high projectile energy for such a single shot test, and I don't know what "alignment" issue you're talking about...the biggest issues are on the pulsed power supply side, and when scaling up to the levels of the Outsider shot and keeping weapon length short enough to fit in a ship, preventing vaporization of the projectile is going to become a big problem as well.

That record was made with one shot, zero repeat rate, no requirement for precise control or shot-to-shot repeatability, an experimental prototype for a weapon with planned engagement ranges that would be point blank even for Terran ships in Outsider, and two decimal orders of magnitude difference in projectile energy content between it and the Outsider weapons. They certainly would have made a lot of progress by the time Outsider takes place, but given the difficulties in scaling up mass drivers of any sort, the velocity and energy performance of the equipment described is not unreasonable. There are physical limits for what you can do with electromagnetic acceleration as well, and other considerations that might lead to you sacrificing velocity for control, repeatability, payload survival, etc.

My main surprise is actually their lack of particle beam technology...this can be thought of as taking the extreme of scaling mass down and velocity up, but it's much easier to accelerate charged particles, and there are approaches that sidestep all the switching speed issues that scale up so badly with projectile velocity. We're probably closer to having particle beam weapons than we are to railgun weapons, they just aren't useful in atmosphere.

[dfacto]

Ablation is only an issue for deployment as a working weapon, not for achieving a high projectile energy for such a single shot test, and I don't know what "alignment" issue you're talking about...

Current problems with the rail itself are ablation and the rail buckling after each shot, requiring realignment if it is to shoot again. Can't really have a gun shoot twice if your barrel is warped.

My main surprise is actually their lack of particle beam technology...this can be thought of as taking the extreme of scaling mass down and velocity up, but it's much easier to accelerate charged particles, and there are approaches that sidestep all the switching speed issues that scale up so badly with projectile velocity. We're probably closer to having particle beam weapons than we are to railgun weapons, they just aren't useful in atmosphere.

How is that supposed to work? Particles are easier to accelerate, but a particle cannon would still require extreme amounts of power (considering that the difference in required acceleration is huge), and unless you create a particle hose to spray an enemy over a long period of time I can't see it being a realistic weapon against a ship with any shielding.

I'm really betting on advanced railgun tech before particle cannons.

[Mjolnir]

How is that supposed to work? Particles are easier to accelerate, but a particle cannon would still require extreme amounts of power (considering that the difference in required acceleration is huge), and unless you create a particle hose to spray an enemy over a long period of time I can't see it being a realistic weapon against a ship with any shielding.

Of course it still requires large amounts of power, you're just not going to deposit a large amount of energy into your target without putting that energy in somewhere. Railgun, linear synchronous motor, particle beam, laser, kinetic missile, the same goes for all of them. Not sure where you're going here.

Acceleration is an issue for railguns because you must pour a lot of energy into a single projectile before it leaves the rails, switching and controlling huge currents on nanosecond timescales and delivering all the energy in microseconds. Particle beams don't have this requirement. Even a shot of the same total energy that lasts only a few milliseconds would use far lower peak power, given similar efficiency. And efficiency can potentially be greater, because you're accelerating particles with a high charge to mass ratio rather than driving currents through a macroscopic projectile to produce a magnetic field to work against.

The big scientific accelerators are built to get higher and higher particle energies, but that's not needed in a weapon...there's no major advantage to throwing particles at 0.999999991c instead of 0.99c...the main thing affected by adding more nines of c is ability to focus the beam at long distances and counter bloom effects. The sort of accelerator I envision is a simple single stage linac much like some of the earliest particle accelerators built or those currently in widespread use as medical equipment, only with an enormous beam current by research/medical accelerator standards. Accelerators that are essentially what is needed have existed for decades, they simply need to be scaled up in beam current rather than in particle energy, something that is relatively simple to do.

[dfacto]

Of course it still requires large amounts of power, you're just not going to deposit a large amount of energy into your target without putting that energy in somewhere. Railgun, linear synchronous motor, particle beam, laser, kinetic missile, the same goes for all of them. Not sure where you're going here.

You say that railguns take too much energy, etc etc; The future is in Particle cannons.

Which would take far more energy to rival the destructive effect of rounds in the kilo range. Plinking your enemies with solitary particles isn't going to do damage.

Yes, accelerating particles close to c is much easier than accelerating metal slugs. But metal slugs hitting with Gigajoules of energy tear ships open. Particles hitting with Gigajoules of energy strip miniscule parts of the ship off or simply penetrate through it. If you want to do serious damage with particle weaponry you will need a LOT of particles.

And then you'll have to contend with the inevitable magnetic shielding which will be put on ships to deflect particle beams.

You can't put anything on a ship to deflect a relativistic slug except for another slug launcher.

Bottom Line: I doubt particle cannons will be realistically able to compete with railgun tech anytime soon because to get a similar effect you will need absurd amounts of power.

[Mjolnir]

You say that railguns take too much energy, etc etc;

No. That is not at all what I said. It's not even close.

The future is in Particle cannons.
Which would take far more energy to rival the destructive effect of rounds in the kilo range. Plinking your enemies with solitary particles isn't going to do damage.

I haven't suggested anything remotely like firing solitary high-energy particles, I was in fact very specifically describing the very opposite...low particle energies compared to research/medical accelerators, and very high beam currents.

And you appear to remain quite confused about energy and power. Regardless of how much mass a projectile has, it has no more energy than you put into it. Power depends on how fast you put that energy in...given equal efficiency and averaging power over the shot, a 1 gigajoule 1 ms particle beam shot takes 1/100th the peak power of a 1 gigajoule railgun shot that takes 10 µs to travel down the rails, and has nothing like the pulse shaping requirements that a railgun has. And with the low particle energy requirements of a weaponized particle beam, there may be significant efficiency gains due to the fact that you're accelerating charged particles.

Yes, accelerating particles close to c is much easier than accelerating metal slugs. But metal slugs hitting with Gigajoules of energy tear ships open. Particles hitting with Gigajoules of energy strip miniscule parts of the ship off or simply penetrate through it. If you want to do serious damage with particle weaponry you will need a LOT of particles.

And as I just said, you don't need particles with extremely high energies, so the particles will not just shoot through the ship without depositing their energy. We're talking about what's essentially low energy alpha radiation at extremely high intensities...it won't go through the ship, it'll be absorbed by what it hits. And if the shot has gigajoules of energy, the result won't be stripping minuscule parts of the ship off.

And then you'll have to contend with the inevitable magnetic shielding which will be put on ships to deflect particle beams.

You can't put anything on a ship to deflect a relativistic slug except for another slug launcher.

First, nobody is launching relativistic slugs. Even if they fired slugs at a hundred times the current 45 km/s record, that'd still be <2% of c, nowhere near relativistic. This is another advantage of particle beams...the lower flight time makes it easier to actually hit the target.

Second, magnetic shielding is a possible approach to defense against charged particle beams, but there's no reason to expect it to be a perfect defense. You need to produce a strong external magnetic field and support it against an impacting weaponized particle beam...this is not going to be trivial. It's much easier to produce an intense magnetic field deep inside an accelerator than it is to surround a ship with one.

And in the Outsider universe, it's demonstrated not to be a perfect defense...similar weapons, scaled up even further, are the primary armament of both sides in the war.

Bottom Line: I doubt particle cannons will be realistically able to compete with railgun tech anytime soon because to get a similar effect you will need absurd amounts of power.

You haven't done anything to demonstrate that.

[Mjolnir]

In addition to all of that, magnetic fields are only an effective defense against charged particle beams. The particles of the beam needn't remain charged after being accelerated...electrons can be injected after the final focusing/fine aiming stage to neutralize them. Apart from making it harder to defend against, this will reduce blooming of the beam due to self repulsion, increasing its effective range.

[dfacto]

I haven't suggested anything remotely like firing solitary high-energy particles, I was in fact very specifically describing the very opposite...low particle energies compared to research/medical accelerators, and very high beam currents.

Just so I'm sure I understand you here: low energy, lots of particles? And when you say low energy you mean high speed, but low mass, so low KE per particle?

And you appear to remain quite confused about energy and power. Regardless of how much mass a projectile has, it has no more energy than you put into it.

I know.

Power depends on how fast you put that energy in...given equal efficiency and averaging power over the shot, a 1 gigajoule 1 ms particle beam shot takes 1/100th the peak power of a 1 gigajoule railgun shot that takes 10 µs to travel down the rails, and has nothing like the pulse shaping requirements that a railgun has.

Out of curiosity, what's the formula/formulas used here? Not to be a doubter, but you're throwing numbers around with no references.

And as I just said, you don't need particles with extremely high energies, so the particles will not just shoot through the ship without depositing their energy. We're talking about what's essentially low energy alpha radiation at extremely high intensities...it won't go through the ship, it'll be absorbed by what it hits. And if the shot has gigajoules of energy, the result won't be stripping minuscule parts of the ship off.

So you would want something with ~15,000 km/s speed and energy of 110TJ/kg (http://en.wikipedia.org/wiki/Alpha_decay)? That would require a shot containing grams of material. How does this compare to conventional linear accelerator injections, and what does that mean for energy requirements? Additionally, how would you deal with the acceleration itself? You can't have an emitter as a source because you will need very large amounts of particles all traveling in a tight bundle, and you can't have a kilometers long accelerator either. Would you use a cyclotron for initial acceleration before injecting the shot into a linear accelerator (barrel)?

This is another advantage of particle beams...the lower flight time makes it easier to actually hit the target.

Indeed. But remind me why you wouldn't just create a more powerful laser and tag ships multiple light seconds away with ease?

You haven't done anything to demonstrate that.

Brb, getting a Phd in physics.

[BattleRaptor]

Not quite true Mjolnir, Magnatized plasma field extending a few million kilometers wouldnt have to be very dense to recharge some of the particles in a dense neutral particle beam and have the beam rip itself apart due to electrostatic repulsion and particle collisions.

The beam wouldnt be stoped but when it reaches the target it could be highly unfocused.

The only problem with such a "shield" is that it would require extremly efficent high tempreture conductors to last long enough to cause a reasonble effect before vaporising.
So it wouldnt be a system installed on ships, but maybe as a kind of disposable shield system that seperates from ships before activating.

[Mjolnir]

I haven't suggested anything remotely like firing solitary high-energy particles, I was in fact very specifically describing the very opposite...low particle energies compared to research/medical accelerators, and very high beam currents.

Just so I'm sure I understand you here: low energy, lots of particles? And when you say low energy you mean high speed, but low mass, so low KE per particle?

Exactly. Still highly relativistic, but that's not at all hard to achieve with particle accelerators.
Relativistic kinetic energy: E = m*c^2/sqrt(1 - (v/c)^2)
Proton mass: 938 MeV/c^2
WolframAlpha: http://www.wolframalpha.com/input/?i=%2 ... 2%29*c%5E2

0.99c: 5.7 GeV/proton
0.9c: 1.21 GeV/proton
0.5c: 145.1 MeV/proton

Out of curiosity, what's the formula/formulas used here? Not to be a doubter, but you're throwing numbers around with no references.

Power is just energy (work) over time: P = dW/dt
Imparting the same energy over half the time means double the power. And time in the weapon:

t is time time spent in the gun, a is the acceleration, v is the end velocity, D is the length of the gun.
D = 0.5*a*t^2, a = v/t

Some algebra gets you:
2*D/v = t

So time scales proportionally to barrel length and inversely proportional to exit velocity. Given the same projectile energy and the same efficiency at converting energy into kinetic energy of the projectile, peak power scales inversely with weapon length and in direct proportion to the exit velocity. There's no simple equations for modeling losses, but generally the faster things happen, the more you leave the system ringing after a shot with excess energy that needs to be absorbed by the cooling systems...plus the more you lose to EM radiation.

Railgun projectiles don't stay in the gun for long...about 10 microseconds was quoted for the Navy railguns. Making the weapon longer helps, but also produces longer conductors that slow pulse rise times and increase losses, plus experience more severe stresses during firing...also makes the thing harder to aim. Long weapons are probably going to be something more like a coilgun, more closely related to a linear synchronous motor than to a railgun.

So you would want something with ~15,000 km/s speed and energy of 110TJ/kg (http://en.wikipedia.org/wiki/Alpha_decay)? That would require a shot containing grams of material. How does this compare to conventional linear accelerator injections, and what does that mean for energy requirements? Additionally, how would you deal with the acceleration itself? You can't have an emitter as a source because you will need very large amounts of particles all traveling in a tight bundle, and you can't have a kilometers long accelerator either. Would you use a cyclotron for initial acceleration before injecting the shot into a linear accelerator (barrel)?

For Outsider Terrans, I'm thinking about something with shots in the milligrams to grams range, not too far off from a baby version of the Loroi and Umiak plasma weapons. It's vastly greater than what's typically used in research accelerators, but the focus with research accelerators has been to achieve vastly greater particle energies, not beam currents. There will likely be plenty of issues with scaling beam intensity up, but not as severe as for scaling railgun velocities up...at the worst, you'll have to gang up multiple beam lines in parallel.

Huge beam intensities simply haven't been a particularly great design goal for research accelerators...about the only thing it would be useful for would be a space weapon without a space warship to mount it on, though some applicable work has been done for things like ion beam and electron beam milling/drilling machines. Looking at some numbers, I underestimated the energy of low energy alpha radiation, but the 0.9-0.99c range I was thinking of is still very far away from being so energetic that it passes through the target without depositing most of its energy. The impact characteristics *would* be different, there would be less momentum for the amount of energy, but such a weapon should still be able to deal large amounts of damage.

I don't envision any cyclotron, just a straight linear accelerator...more straightforward to scale up in beam intensity, and it's what existing particle beam milling machines use. And probably with a particle source more like those used in plasma drives in development now, such as VASIMR.

This is another advantage of particle beams...the lower flight time makes it easier to actually hit the target.

Indeed. But remind me why you wouldn't just create a more powerful laser and tag ships multiple light seconds away with ease?

Well, lasers are generally even less efficient and more difficult to scale up in power. And in fact, the ones most likely to be used as really high power (MW-class) weaponry are free electron lasers, which use a high-power particle accelerator (generally a linac) to produce the laser beam.
http://www.onr.navy.mil/Media-Center/Pr ... stone.aspx
http://www.onr.navy.mil/Media-Center/Fa ... Laser.aspx

[fredgiblet]

Railgun projectiles don't stay in the gun for long...about 10 microseconds was quoted for the Navy railguns. Making the weapon longer helps, but also produces longer conductors that slow pulse rise times and increase losses, plus experience more severe stresses during firing...also makes the thing harder to aim. Long weapons are probably going to be something more like a coilgun, more closely related to a linear synchronous motor than to a railgun.

Don't forget the cost of extended a precision-engineered barrel, beyond the engineering challenge of creating it paying for it is an issue as well, all those obstacles cost money to overcome.