Did the E-D really do that badly in GEN?

[Patrick Degan]

For me, electrostatic -> time-invariant distribution of charge and magnetostatic -> time-invariant distribution of currents. A charge-separated system in which there was motion of the charges would lead me to classify it as electrodynamic, not electrostatic. Electrostatic and magnetostatic situations have direct consequences in Maxwell's equations, whereas I don't think a criterion based purely on charge separation does.

Now, the continuity argument; when some current or charge distribution is altered there will be time-dependent behaviour, but these transients will die out over time after the intial event (probably, but not necessarily quite rapidly). In general the transients will not be characterised by a single frequency but a continuous range of them.

OK, now I see your perspective on this.

If you're not pushing all that mass through space, you still would have to apply a proportional amount of energy to the ship to "lighten" its load. My guess is that, as the "mass-lightening" effect is only applying sufficent force to reduce or negate its gravitational effect upon the surrounding space/time, this operation would be less power-intensive than if the engines simply burned fuel directly to accelerate the ship through space. Granted, the whole concept is pretty dodgy.

I don't think I understand. Its gravitational influence should be minimal in any case. Most of the work done must be accounted for by simply pushing propellant. Anyway, lightening the ship's mass should lighten the available fuel, which would reduce the energy available from annihilation!

As I said, the whole concept is dodgy. And perhaps the term "gravitational influence" is not the ideal one to use; rather, the effect of an accelerating mass upon the surrounding space/time continuum, which is analogous to a gravitational influence with regard to moving bodies in free space. But logically, you would still be faced with the mass/energy equivalency problem.

We've already seen how efficent weapons' targeting is in Star Trek; poor enough, for example, where Riker was able to evade a Borg tractor beam simply by turning the battle module hard to port in "Best Of Both Worlds (2)", where Locutus was fooled by the saucer module's antimatter fireworks show and couldn't find a small shuttlecraft in the same episode, and where the Defiant missed several times against the Lakota at close range in "Homefront". The warships in Trek seem to require fixed firing solutions rather than dynamic target-tracking to actually be able to score hits with any degree of reliability.

Yes, targetting often appears poor (and sometimes, very good). But why would that mitigate against lasers as weapons? Phasers are beam weapons too, and yet are extensively used, even relied upon over torpedos in some situations.

Because any weapon is only as good as the ability to aim it at the target.

To address a point you raised earlier in regards to lasers being "underrated" as weapons in comparison to particle beams, the main reason would have to be the sheer amount of time it would take for a laser to burn through a hull plate, while a particle-beam breaks molecular bonds through high-velocity particle collision and thus renders the hull plate's material progressively brittle. In that sense, a particle-beam would be a "blasting" rather than a burning weapon and would get the job done quicker. Particularly against material which posseses a high thermal resistance.

For lasers: the effects of the laser depend strongly on wavelength. At shorter wavelengths the damage will become very non-thermal, ionisation, some transmission through the plating, etc. At very high intensities the damage will also become non-thermal. However, as far as thermal effects go, I think the point about industrial cutting remains. It's not particle beams, but lasers that are being used in industry and starting to appear as military devices.

Industrial cutting applications are a whole different matter than use as weapons. Industrial lasers are quite useful but time-intensive applications and ones where precision cutting is an absolute requirement. And in ship-to-ship combat, ionisation damage won't guarantee the crippling or destruction of an enemy vessel.

For particle beams: the problems with them are that accelerators have very poor efficiency, take ages to build up energy (when synchrotrons are used) are enormous, and don't produce very high luminosities at the end of it all. Witness the free-electron laser; fed by a particle accelerator, the FEL has the worst efficiency of any laser I'm aware of, although it does have certain interesting abilities. I'm also unconvinced that the beam divergence of even a neutral particle weapon could ever be particularly impressive.

The efficency of present-day lasers is none too impressive either; they gobble power and are useful mainly where time is not a vital consideration or against thinly-plated targets (such as with the prototype military lasers now being developed for use as anti-ASM weapons). The beam is attenuated by atmospheric refraction (while particle-beams are worse in this regard), which is why their best performance is over short distances or in a vacuum environment. And a reflective surface affects a laser the same as any other light source.

[ClaysGhost]

As I said, the whole concept is dodgy. And perhaps the term "gravitational influence" is not the ideal one to use; rather, the effect of an accelerating mass upon the surrounding space/time continuum, which is analogous to a gravitational influence with regard to moving bodies in free space. But logically, you would still be faced with the mass/energy equivalency problem.

Minimal, surely (the effect on the surroundings). Is this at warp or impulse? I think mass lightening is often proposed to solve the wrong problem. You really need a propelling force from outside the lightened object - slap-on discs to make heavy cargo containers less massive and more handleable would be much funkier.

Because any weapon is only as good as the ability to aim it at the target.

Sure, but it's not a laser-specific disadvantage, but an unguided weapon problem generally (although if the targetting's that bad, it'd raise questions as to how well a guided weapon would perform anyway).

Industrial cutting applications are a whole different matter than use as weapons. Industrial lasers are quite useful but time-intensive applications and ones where precision cutting is an absolute requirement. And in ship-to-ship combat, ionisation damage won't guarantee the crippling or destruction of an enemy vessel.

Well, the ionisation takes place at the front of a shock travelling through the target, although I emphasize that this effect requires either very high luminosities or weapon frequencies at the far-UV and higher. Even if radiation didn't penetrate the hull but was completely absorbed by either the armour or by the ionised hull material, free charges could be hazardous to electrical systems, ignoring the actual damage to the hull itself. I don't see that particle weapons can necessarily guarantee destruction either - the hull material would likely be more efficient at stopping protons or neutrons than short-wavelength radiation, so although the target ends up with brittle armour (assuming that the accelerator can get shots off at a decent rate) it saves the crew and internals. The laser could still pose a radiation risk to crew behind armour (*if* the frequency range available extends far enough into X-rays, which is far from certain - you might end up using a FEL, which really does have serious efficiency problems).

Lasers may not be the ideal weapon (is there any such beast?) but particle accelerators are downright bad.

The efficency of present-day lasers is none too impressive either; they gobble power and are useful mainly where time is not a vital consideration or against thinly-plated targets (such as with the prototype military lasers now being developed for use as anti-ASM weapons).

I don't see why maybe 40% efficiency (for non-semiconductor lasers) is so terrible when a typical high-energy particle accelerator will be somewhere around 1% and of greater size and mass. You'd have to build the ship around a particle weapon, most likely, and I imagine that the field of fire would be limited to a fixed axis (whilst you could bend charged particles to emit them from several places, they would radiate EMR as they turned - apart from the safety aspect, this is just inefficient). The time issue can be reduced by using higher power (most cutting lasers seem to operate on at the kW level - military lasers seem to operate from 200kW up to 10MW), and is not as serious as the very large amount of time taken for a synchrotron to build up a beam of particles. Linacs don't take as long, but then you have the size/mass issue coming in again, although synchrotrons themselves are hardly low-mass, low-volume items.

The beam is attenuated by atmospheric refraction (while particle-beams are worse in this regard), which is why their best performance is over short distances or in a vacuumenvironment.

Certainly (although there is a frequency dependence), but in lasers vs. particle beams as space weapons this isn't really an issue.

And a reflective surface affects a laser the same as any other light source.

Reflectivity collapses rapidly into UV wavelengths, possibly earlier if the reflective coating is not maintained well. I don't know how much covering a ship in a highly reflective material would cost; I can't tell if it would be worth it.

In summary, I agree that lasers have their disadvantages. But I think the pros outweigh the cons for lasers used as part of a multi-weapon approach to arming a starship. I don't think that's the case for particle weapons.

[Patrick Degan]

As I said, the whole concept is dodgy. And perhaps the term "gravitational influence" is not the ideal one to use; rather, the effect of an accelerating mass upon the surrounding space/time continuum, which is analogous to a gravitational influence with regard to moving bodies in free space. But logically, you would still be faced with the mass/energy equivalency problem.

Minimal, surely (the effect on the surroundings). Is this at warp or impulse? I think mass lightening is often proposed to solve the wrong problem. You really need a propelling force from outside the lightened object - slap-on discs to make heavy cargo containers less massive and more handleable would be much funkier.

From TNG-onward, it appears that the subspace based mass-lightening effect is integral to both warp and impulse drives. In fact, in the DS9 pilot, Chief O'Brien generates a subspace mass-lightening field surrounding the space station in order to move it rapidly from Bajor orbit to the periphery of the wormhole using only the manoeuvering thrusters.

Because any weapon is only as good as the ability to aim it at the target.

Sure, but it's not a laser-specific disadvantage, but an unguided weapon problem generally (although if the targetting's that bad, it'd raise questions as to how well a guided weapon would perform anyway).

You still have to aim beam weapons, even if they're turret-mounted.

Well, the ionisation takes place at the front of a shock travelling through the target, although I emphasize that this effect requires either very high luminosities or weapon frequencies at the far-UV and higher. Even if radiation didn't penetrate the hull but was completely absorbed by either the armour or by the ionised hull material, free charges could be hazardous to electrical systems, ignoring the actual damage to the hull itself<snip>

Since a ship must be shielded and insulated simply to protect its crew and electronics from cosmic background and solar flux radiation to start with, I do not see ionisation as presenting a vital threat; not sufficent to knock out the ship on its own.

I don't see why maybe 40% efficiency (for non-semiconductor lasers) is so terrible when a typical high-energy particle accelerator will be somewhere around 1% and of greater size and mass. You'd have to build the ship around a particle weapon, most likely, and I imagine that the field of fire would be limited to a fixed axis (whilst you could bend charged particles to emit them from several places, they would radiate EMR as they turned - apart from the safety aspect, this is just inefficient). The time issue can be reduced by using higher power (most cutting lasers seem to operate on at the kW level - military lasers seem to operate from 200kW up to 10MW), and is not as serious as the very large amount of time taken for a synchrotron to build up a beam of particles. Linacs don't take as long, but then you have the size/mass issue coming in again, although synchrotrons themselves are hardly low-mass, low-volume items.

Perhaps (although I've not seen data on lasers reaching such comparatively high efficencies), but unless engineering makes significant advances in miniaturisation, I don't see any shipborne combat laser of appreciable power (sufficent to cut through a target thicker than the skin of a missile) existing outside a fixed-axis mounting either. These issues are some of the reasons why all the beam weapon schemes for SDI came up bust fifteen years ago.

Reflectivity collapses rapidly into UV wavelengths, possibly earlier if the reflective coating is not maintained well. I don't know how much covering a ship in a highly reflective material would cost; I can't tell if it would be worth it.

To protect the ship in combat, the cost would be quite justifiable, and amortised through line production of war vessels.

In summary, I agree that lasers have their disadvantages. But I think the pros outweigh the cons for lasers used as part of a multi-weapon approach to arming a starship. I don't think that's the case for particle weapons.

Hmm... A point worthy of consideration, but dependent on a number of factors. Certainly, sole dependence upon beam weapons would be unwise in any case.

[ClaysGhost]

From TNG-onward, it appears that the subspace based mass-lightening effect is integral to both warp and impulse drives. In fact, in the DS9 pilot, Chief O'Brien generates a subspace mass-lightening field surrounding the space station in order to move it rapidly from Bajor orbit to the periphery of the wormhole using only the manoeuvering thrusters.

Oh yes, I'd forgotten that one. Must've been the trauma.

You still have to aim beam weapons, even if they're turret-mounted.

Sure, but it's not a laser problem per se. Actually, would guided missiles be any better off? They've got the same problem of target detection and tracking but with presumably poorer sensors than those that will fit on a starship. If the missile and starship exchange sensor data to cope, and the starship can't actually shoot straight on its own, I think the missile would still have problems.

Since a ship must be shielded and insulated simply to protect its crew and electronics from cosmic background and solar flux radiation to start with, I do not see ionisation as presenting a vital threat; not sufficent to knock out the ship on its own.

It doesn't occur as an isolated phenomenon on its own, but as part of a series of connected effects. Of course, thicker shielding will reduce the risk, but increase the mass.

Perhaps (although I've not seen data on lasers reaching such comparatively high efficencies),

40% is CO2. Semiconductor lasers are of higher efficiency, and their power output is gradually increasing over time (you can get semiconductor laser diodes suitable for cutting nowadays) although obviously there are other laser types with far higher power output but lower efficiency). They'll never be MW-level though. Compared to particle accelerators there are plenty of types that do far better, although noble-gas ion lasers and He-Ne lasers have the same low performance as accelerators. I don't know how good the neodynium (sp) -glass types are. I'm really struggling to think of a high efficiency weapon in any case. I suppose missiles won't have high efficiency and may be interceptable/slow, but theywon't release their waste energy inside the ship that launched them either.

but unless engineering makes significant advances in miniaturisation, I don't see any shipborne combat laser of appreciable power (sufficent to cut through a target thicker than the skin of a missile) existing outside a fixed-axis mounting either. These issues are some of the reasons why all the beam weapon schemes for SDI came up bust fifteen years ago.

IR lasers could plausibly operate from a central station with the beam relayed to exterior mountings as required. High frequency lasers would certainly have to be fixed axis, yes. I'm optimistic about the miniaturisation of lasers for a variety of reasons, but mainly because lasers are an implementation of an optics principle, not any one particular device. There's a lot of room for innovation there, I think. "Beam weapons" includes lasers and particle weapons as well?

To protect the ship in combat, the cost would be quite justifiable, and amortised through line production of war vessels.

Well, it wouldn't if the lasers were UV or shorter wavelength types, and I'm not sure that a quality optical surface could be established to cope equally well with frequencies from far IR to optical, but if it's the loss of a ship vs. the expense of a quality optical surface then I see your point.

In summary, I agree that lasers have their disadvantages. But I think the pros outweigh the cons for lasers used as part of a multi-weapon approach to arming a starship. I don't think that's the case for particle weapons.

Hmm... A point worthy of consideration, but dependent on a number of factors. Certainly, sole dependence upon beam weapons would be unwise in any case.

Yes. Perhaps substitute "energy weapons" for "beam weapons" since both lasers and particle devices can operate pulsed. I suppose it depends on what missiles do.