Questions about UT smoke, lasers, and plasma.

[lwcamp]

Originally Posted by lwcamp

Smoke that blocked vision would stop a modern laser weapon - but the GURPS model is a bad model for it. Lasers are light, and if the light going through a cloud of smoke is mostly scattered from the beam-path before it gets through

Originally Posted by Fred Brackin

All these particles are suspended in the air too and you're exploding the air out of your way because you have to use a frequency of laser light that air absorbs well. The smoke particles wil get blown out of the way too.

Note that the post you are responding to is about near infrared modern laser weapons, which go through air very nicely and would be entirely unsuitable for making evacuated tunnels.

Originally Posted by Fred Brackin

Why is tis smoke scattering light instead of absorbing it? I would expect most smoke (as produced by a smoke grenade or similar source) to be full of carbon particles.

Black smoke would be absorbing light more than scattering it, white smoke would scatter light more than absorb it. White smoke would be better for concealment, since in addition to removing light from the image, it will scatter additional light into the image to create background noise and wash out the image; rather than just making the image dimmer like black smoke would. Modern smoke screens seem to be sometimes white and sometimes dark.

Originally Posted by Fred Brackin

In the end the difference between absorption, reflection and refraction is only going to be a matter of degree. Things that absorb the laser light will heat up and be destroyed first, then the reflectors because they can't reflect the light perfectly and absorb some of the energy in the process. The refractors come last but they aren't perfect either and each tiny microrefractor will eventually pick up enough energy in the process to exceed its' miniscule capacity to absorb the laser light too.

Again, the post you are responding to was referring to modern laser weapons. These have focused beams, rather wide near the laser's aperture but focused down to a tight spot at the target. For most of the laser's path, the light will not be intense enough to heat aerosols to the point that they vaporize. This is helped by the very high surface area to volume ratio of the particles, so they can rapidly shed heat to the surrounding air.

Luke

[Anthony]

Originally Posted by lwcamp

Modern smoke screens seem to be sometimes white and sometimes dark.

Possibly because of ease of production; any color will be opaque if there's enough of it.

[RyanW]

Originally Posted by Anthony

Possibly because of ease of production; any color will be opaque if there's enough of it.

Not really. Most military smoke grenades start off as white, either sugar based slow burn or phosphorus based instant smoke, and get colored whatever is desired. Though I don't know if phosphorus is ever really colored. The M18 uses lactose and potassium chlorate, with dyes for the desired color.

[T.K.]

Originally Posted by sethbrayman

Heh, by definitely I mean backed up by clear use of UT rules or even UT rules and real world science! Unfortunately it doesn't seem like that will be possible, the UT description of the plasma weapon and the UT description of what smoke does, along with how lasers and smoke really work doesn't seem to jive together. I guess that's just SS right...

Well, you see...first I'll leave my common disclaimer for this type of thing:

"
- When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.

- The only way of discovering the limits of the possible is to venture a little way past them into the impossible.

- Any sufficiently advanced technology is indistinguishable from magic.
"

What I mean is, even though its clearly not magic, such technology might be so cutting edge that the real inward workings of it might be beyond grasp for our current thought capability.

For our current physics model of the universe and existence, we have already set in place paradigms that we abide to. What if those are incomplete? What if they're flat out wrong?

A Scorching Flame Breath IS technology for someone with a flamethrower.
An aspirin pill IS magic for a terribly ill 5th century citizen.

On top of that, you're (imo) hanging way too much on what you already defined as _flavor_ aka what the author might've thought, at the time made sense to him, considering the type of setting and knowledge he had at the time of production.

[Fred Brackin]

Originally Posted by lwcamp

Again, the post you are responding to was referring to modern laser weapons. These have focused beams, rather wide near the laser's aperture but focused down to a tight spot at the target.

Someone who is hoping to stop lasers and/or plasma beams will 1 to 10 hexes of smoke will be probably dropping his smoke grenade near himself and not trying to lay it in front of the firer. He has a lot more control of it that way. He certainly doesn't want his smoke grenade to bounce.

Aside from smoke grenades (which I admit usually produce lighter colored smoke) the main smoke producing schemes dump diesel into a vehicles' exhaust and partially combust it. This is certainly the way to make big smoke clouds and it also makes very dark smoke indeed.

Most smoke v. lasers schemes will be sharply limited by the principle that if you can't shoot a laser through it you can't see through it or probably breathe it either.

[Ulzgoroth]

Originally Posted by Fred Brackin

Most smoke v. lasers schemes will be sharply limited by the principle that if you can't shoot a laser through it you can't see through it or probably breathe it either.

Breathing probably isn't a problem in UT. Air filters are a basic feature of any serious UT combat loadout. Seeing might be, but you can use HUD assistance, non-visual sensors, and potentially IR/hyperspectral vision to try to make up for it.

[Fred Brackin]

Originally Posted by Ulzgoroth

Breathing probably isn't a problem in UT. Air filters are a basic feature of any serious UT combat loadout. Seeing might be, but you can use HUD assistance, non-visual sensors, and potentially IR/hyperspectral vision to try to make up for it.

These sound like battlesuit subsystems. The armor on battlesuits is usually enough to stop sub-cannon sized lasers anyway.

[Ulzgoroth]

Originally Posted by Fred Brackin

These sound like battlesuit subsystems. The armor on battlesuits is usually enough to stop sub-cannon sized lasers anyway.

Nah, all easy to include in even a light infantry loadout. Maybe excepting the non-visual sensors, but I think some of those (in their smallest, weakest versions) are quite compact too. Extended-spectrum vision comes in easy wear-on-your-face form factors, HUD capability can be included on anything with a faceplate and can be driven by a computer smaller than a smartphone, and I think all the infantry helmets include breathing filters.

[Fred Brackin]

Originally Posted by Ulzgoroth

HUD capability can be included on anything with a faceplate and can be driven by a computer smaller than a smartphone, and I think all the infantry helmets include breathing filters.

The Faceplate is optional on the Light Infantry helmet and it doesn't seal even if you are wearing a Tac Suit or heavier. You need the Combat Infantry Helmet for that. After you add al the stuff you want to the Light helmet you might as well go with Combat model which has all that built in.

[Ulzgoroth]

Originally Posted by Fred Brackin

The Faceplate is optional on the Light Infantry helmet and it doesn't seal even if you are wearing a Tac Suit or heavier. You need the Combat Infantry Helmet for that. After you add al the stuff you want to the Light helmet you might as well go with Combat model which has all that built in.

Yeah, I'd forgotten how featureless the minimal helmet was. You could add a simple Filter Mask, if you really wanted to not use the Combat Infantry Helmet, but usually I'd say just go for the fully-featured headgear. It's lighter than the LIH+visor anyway (though it does cost more and have slightly less face DR).

Definitely not a battlesuit system, though. It's naturally suited to pair with a tacsuit, but can be worn with lesser kits if desired.

Small sensor units make for easily man-portable four pound shoulder mounts, though the range is fairly short if you can't use LADAR and want better resolution than search radar.