Effectiveness of ME kinetic barriers

[Perseid]

Since I asked about this I've started to reply ME2, and I've noticed that barriers are used more like force fields in Star Trek than anything else. They are used to contain the atmosphere around the helm when the Normandy is going down at the beginning, and Joker seems to have an active barrier around him, again acting to protext him against the lack of atmosphere that he could be exposed to.

I don't know whether the cut scenes are cannon, but for this I'd expect kinetic barriers to be able to interact with everything down to an atomic level, since they can act as atmosphere shields. So as people have said above, any weapon that would have a kinetic component, even if it's a particle pulse weapon, should be deflected, at least in part, by the barriers.

So given we see Particle beam weapons pass right through the barriers (which they shouldn't), that must mean that there must be something in play similar to what Ted C mentioned, that being the barriers have some form of sensor system to them which detects something coming towards the ship and puts the barrier between the ship and the incoming threat, with anything above a certain velocity not being detected...
Ugh makes my head hurt, the very idea that the barriers can somehow detect a 20KG projectile travelling at 0.013c (or whatever) and be able to deflect it, when the main sensors can't detect a ships mass that's hiding it's thermal emissions is rediculous and laughable.

From what little I remember of the Mass Effect codex, the way that shields work is that they generate a really sharp gravitational field gradient at a certain distance away from the emitter. Smaller objects that hit that gradient experience a sharp change in mass at the front, and the resulting change in momentum deflects sufficiently small, fast-moving objects. Larger objects can pass through without being deflected for whatever reason.

But we never see a large object hit barriers. We know that infantry level barriers can deflect "grain of sand" size projectiles, but at the same time a ship can generate barriers as I've said above. The tech is too varied within the setting from a game play, cut scene and codex point of view, hence me opening with "They work as advertised".

[Grumman]

I don't know whether the cut scenes are cannon, but for this I'd expect kinetic barriers to be able to interact with everything down to an atomic level, since they can act as atmosphere shields. So as people have said above, any weapon that would have a kinetic component, even if it's a particle pulse weapon, should be deflected, at least in part, by the barriers.

Maybe it is. But the same force being exerted on a heavy, fast atom isn't going to deflect it as much as on a lighter, slower atom, so shielding that keeps atmospheric losses down to an insignificant level will not necessarily stop a particle cannon punching straight through it.

[Starglider]

But we never see a large object hit barriers.

We see the Normandy SR2 hit several pieces of giant metal debris at several hundred kph. Mostly glancing blows, but the debris is hull sections from much larger ships. The result is a reduction in barrier strength to 40%. If you don't have the top-spec kinetic barriers you also take some minor internal damage from the feedback (that destroys Legion but doesn't seem to cause any reduction in the ship's ability to fight the Collector warship).

I think it's perfectly reasonable to say that kinetic barriers work on slugs travelling at 0.013c but not on a stream of particles travelling at >0.99 c; it's a plausible technological limitation. Presumably there is an absolute limit on how fast energy can be bled off per particle as they cross the finite width of the barrier.

[Simon_Jester]

They would, however, at least partially reduce the impact energy of the beam.

Also, if you don't hit such a barrier perpendicular to the plane of the barrier field, the rapid deceleration of particles hitting the field will drastically fan out the beam, dispersing its zone of effect across a wider part of the hull than would otherwise be the case.

This may or may not make much practical difference depending on the impact energy, of course. A kiloton-range particle bolt might well become a good deal less effective if it hits thirty square meters of hull rather than ten, but a gigaton-range bolt will still be overwhelming and devastating unless I am badly underestimating Mass Effect material science technology.

[Caiaphas]

[quote="Simon_Jester"]Also, if you don't hit such a barrier perpendicular to the plane of the barrier field, the rapid deceleration of particles hitting the field will drastically fan out the beam, dispersing its zone of effect across a wider part of the hull than would otherwise be the case.[quote]

Wouldn't this be at least partially dependent on the momentum of the particles in the beam? I mean, yes, for any particle beam to be of any use you need to fire them at relativistic velocities anyways, but having more momentum (shooting them faster) does at least two things to my line of thinking which would help mitigate beam spread.

One, the particles are moving faster. Time and length dilation reduce the transit time and total distance between the shield and the hull, meaning that there's less time for the mass effect field to deflect it, ergo, less spread.

Two, the particles are much heavier a la relativistic mass gain, so it's much more difficult for them to be deflected.

[Simon_Jester]

One and two are co-equal when you apply relativity consistently- the particle's increase in mass as it approaches c IS the particle's increase in momentum, because "relativistic mass" isn't actually a thing in relativity, it's just what you get when you divide (relativistic) momentum by velocity.

I'm actually not sure how it'd pan out; a lot depends on the actual thickness of the fields involved. But if a mass effect field actually works by imparting a constant delta-v to incoming objects, AND if that delta-v is sufficient to stop slugs traveling at at least a few percent of the speed of light... I honestly don't think it'll matter.

The incoming massive object still bleeds off a constant amount of its kinetic energy penetrating the barrier no matter how fast it moves- although this may only be a small percent of total energy for a highly-relativistic mass. And while it may experience only a small change in velocity along its line of flight, delta-v perpendicular to the line of flight is still in play.

Then again, a lot depends on how much standoff distance there is between the mass effect field and the hull. And whether you are, say, matching a kinetic barrier capable of stopping .1c projectiles against a .5c beam, or matching a barrier that stops .02c projectiles against a 0.99997c beam.