How Overpowered Scifi Space Combat Would Be

[KerikBalm]

9 hours ago, Spacescifi said:

Maybe science fiction that has fictional stuff should be called Science Fantasy then?

I often refer to a lot of Science fiction as Fictional science. Only "hard" Sci-Fi is actually scientific fiction, by my definition. I also like to call it: Fantasy, in spaaaaccceeee!!! which would includethings like star wars.

8 hours ago, ARS said:

If I had to express my opinion, I think the space combat would be fought primarily by kinetic weapons (railguns, coilguns, etc.) over extremely long distance. Energy weapon tend to get weaker with distance, judging from collimation and energy dissipation, while missiles has limited propellant, which, since the target spacecraft could maneuver away (and has way more deltaV than missiles), even tracking would be ineffective if the target could outmaneuver it, not to mention the missile could be shot down (and warships tend to fit defense turrets for that reason). Even if missile explodes, the fragment it creates may not be any different than a hail of highspeed micrometeorite strikes, which, a military-grade warship operating in space is certainly equipped to deal with that.

#1) Energy weapons will be able to focus out to a diffraction limited distance. If you had a 30 meter mirro/lens, you can focus it doesn to a point at a certain distance, and between that point and the lens/mirror, it gets stronger with distance (like when you use a magnifying glass to burn something, holding the glass to close to the target doesn't work). As I mentioned, large focusing arrays and short wavelengths can get this ranges very high, to the point where the lag from the speed of light is problematic.

#2) A missile using the same type of propulsion as a warship, will have more dV or the same, not less, as it will all be about mass fractions. If you armor your warship to withstand high speed shrapnel, it will certainly have less dV than the missile. Shoot down the missile far enough away, and it only takes a small maneuver to avoid the shrapnel.

#3) It all comes down to the propulsion systems. If we were to engage in space warfare with current/near future tech, or lasers would not be good enough for anything other than point defense. Missiles would be used at long range, possible some kind of railgun firing a guided projectile (a gun-missile hybrid, which we already use very often in conventional warfare). Increase tech a bit more, where you have bulky nuclear (fusion?) drives that don't scale down well (and thus aren't suited for use on missiles), and high frequency lasers, and then it looks like lasers may dominate.

Increase tech even more so that missiles can start achieving substantial fractions of c, then they can jink any laser shots at longer ranges (even 1 AU away allows them ot juse make a small maneuver every 16 minutes to avoid being hit), and start jinking faster as they come within about half an AU. With a good propulsion system and high speed, the transit time over half an AU is small, and they have the dV to jink until the very end (where light speed lag becomes insignificant, and jinking is useless) - giving laser PDWs a very limited amount of time to engage incoming missiles (whose shrapnel clouds will still be very deadly).

So I'd say depending on tech level: Gun-launched missiles > lasers > relativistic missiles.

[Codraroll]

10 hours ago, Spacescifi said:

Maybe science fiction that has fictional stuff should be called Science Fantasy then?

Because anything we dream up that we know does not exist is just that... until we learn otherwise.

Regarding such, it is my approach to modify or enhance or manipulate stuff we already know to make scifi super tech.

There has to be fictional stuff in sci-fi, otherwise it would have been reality already. 

At some point, you MUST assume "this works, somehow". If not with technology, then with economics, or politics, or tactics, or human behaviour, or a bunch of other stuff I can't even imagine at the moment. Those assumptions are absolutely necessary if you want to tell a story beyond current reality - extending even to such near-future stuff as human activity beyond low Earth orbit. If you want to make a story, you have to make assumptions and pull some stuff from your imagination. Don't let "but wait, this doesn't make any sense if you look at it like this" stop your writing. You're making up stuff, and if your story is good enough, nobody will notice. Take Star Wars, for instance, nothing there makes sense if you examine it too closely. That doesn't seem to stop neither fans nor writers.

So yeah, have your aliens use cars and bows and arrows if you want to. As a writer, you can make up the necessary technobabble to make it work. Both Hunger Games and The Avengers did it. If you let trivialities such as reality come in the way of your writing, you will never write anything. Come to think of it, have you even written anything? Or are you just endlessly exploring concepts?

[DDE]

48 minutes ago, Codraroll said:

Don't let "but wait, this doesn't make any sense if you look at it like this" stop your writing. You're making up stuff, and if your story is good enough, nobody will notice.

Somebody will. Most won't.

And for most of those who do notice, it won't necessarily be a showstopper so long as it's internally consistent or does not otherwise undermine the story.

51 minutes ago, Codraroll said:

Come to think of it, have you even written anything? Or are you just endlessly exploring concepts?

*lays low and pretends it doesn't also apply to him*

[Codraroll]

43 minutes ago, DDE said:

*lays low and pretends it doesn't also apply to him*

Heh, I'm guilty too. Got an old script sitting somewhere, intending to finish it ... some day. But I find it enjoyable to try to overcome the technological snags with my own excuses, rather than being frustrated about how it could possibly clash with known science. I mean, when writing, you have the power to make up science and make it work for you rather than the other way 'round. For instance,  my half-finished idea contains a civilization whose greatest achievements involve the dis-coupling of speed and momentum (meaning they can accelerate stuff way past c, but colliding into stuff would not be an issue) and a way of matter-to-energy conversion without doing the detour through antimatter (essentially, they fuel their ships pouring rocks into them, while rods of material not quite unlike iridium is the preferred method of energy storage). How can they do this? In both cases, the answer is "somehow". My biggest excuse is that it's a setting with some magic in it, and if you apply Clarke's third law in reverse, you can handwave it by saying  "Sufficiently basic magic is obtainable through technology". For instance, the space-faring race take generations of research to find a way of delay-free communication, while the race of magical people are just born with telepathic powers, and the two are found to work approximately the same (at least to the point of interfering with each other - both experience the other as random noise). 

I mean, yes, it breaks apart if you analyse it too much, but nobody will even want to do that if there isn't an engaging story told around it. Look at how much The Expanse gets right versus Star Wars from a scientific point of view, and compare the number of articles digging into where their respective science breaks down. Everybody knows how impossible and impractical lightsabers are, but that's irrelevant because their setting is so fun and accessible. It takes a bit more knowledge to see anything wrong with the Epstein drive, but the series is still so niche not many people bother to do so. And there are tons of even more obscure sci-fi out there, whose authors have painstakingly ensured that everything is aligned with the current understanding of science, to the benefit of nobody since most of the text is just esoteric technobabble nobody bothers to read. To boil it down into a simple sentence: "Soft sci-fi can be halfway through a character arc on the other side of the solar system in the same amount of time it takes for hard sci-fi to explain how its propulsion works".

So yeah, story first, science later, if you have time for it at all. If you let science get in the way of your fiction, you won't ever get it told.

Edited July 21, 2020 by Codraroll

[DDE]

48 minutes ago, Codraroll said:

If you let science get in the way of your fiction, you won't ever get it told.

It's worse. I've recently gotten bogged down in... a different kind of minutae.

I'm coming to the realization that this is counterproductive. So here's why everyone should switch to America's four-tank squads...

[KSK]

Personally, I don't think that getting hung up on the labels is particularly helpful for either the reader or the writer.

From the reader's point of view, provided that the story was enjoyable, does it really matter if it was hard sci-fi, soft sci-fi, space opera, space fantasy, fictional science, or whatever? 

From the writer's point of view, I was at a very interesting webinar the other evening put on by our local sci-fi magazine, where one of the speakers made the point that it's possible to know too much about a subject if you want to write about it. By all means do your research and have your writing be plausible but knowing too much can lead you to unconsciously dismiss a whole lot of potentially interesting directions to take your story because 'that's not how it works in reality', when strict adherence to reality (aka hard science fiction or whatever other label you choose to apply)  might not be that important.

What labels are outstanding at though, in my experience, (and I'm not aiming this at anyone on this thread) is giving people an excuse to look down their noses at particular stories or styles of story because 'those aren't proper sci-fi'.

Besides, you invariably get the edge cases where a story crosses genres and attaching a label to it becomes even less helpful. Take Stephen Baxter's Voyage for example, which is so firmly set in the present day that you could make an argument for it being hard sci-fi or alternate history. At the other end of the scale, take Patrick Rothfuss's The Name of the Wind. It's fairly obviously a fantasy story and yet its magic system is extremely constrained by conservation of energy. In that regard, it's far more scientific than pretty much any technology you'll see in a more obviously science-fiction setting such as Star Wars or Star Trek.

And, if you'll excuse the blatant plug, somewhere in the middle you get stuff like my own short story, which combines reasonably hard fictional science with an obviously Clarke tech setting. Or my KSP fanfic for that matter which combines pretty hard sci-fi space travel (as you might expect from a KSP story) with softer sci-fi elements concerning plant science and ecology.

Edited July 21, 2020 by KSK

[kerbiloid]

On 7/17/2020 at 4:48 PM, radonek said:

Yes, antimatter is incredibly dangerous. So was gunpowder at times. Or steam engine. Or nuclear power…

Not exactly.

You can open the gunpowder can, stop the engine, or not engage the nuke, and nothing happens.
But there is no safe state for AM charge. Anything of listed means boom.

In SCP terms,
gunpowder, engine, and nuke are of the Safe class ("if put it into a box and forget, nothing happens"),
while AM is typical Kether ("if put it into a box and forget, destructions and casualties are inevitable").

15 hours ago, Spacescifi said:

For example, the greeks/romans developed primitve steam engine technology, but even if they had went further to actually utilize it in an industrial manner it would not be as efficient as modern tech steam engines 

Since they lacked the fine and precise tools and machinery that made steam engines an efficient choice for the 18th century.

The whole aeolipile physics was totally inefficient, compared to the steam engine.
And they didn't have enough steel in ancient times, and didn't use coke. Their needs of metal were too low to require higher metallurgical productivity, so their furnaces were too small and weak to melt the iron ore.
The precision didn't play role.

14 hours ago, ARS said:

If I had to express my opinion, I think the space combat would be fought primarily by kinetic weapons (railguns, coilguns, etc.) over extremely long distance.

And the ultimate case of kinetic weapons are particle beams.

 

Spoiler

 

Quote

(Mechanized Infantry Rifle Platoon scheme)

 

(Reading the scheme)

"Alternate gunner" =
A gunner with a different mindset, he/she prevents the first gunner from the rigid way of thinking.
There are two of them to have a real pluralism.
They just vote what to do next, that's why the BFV-1 crew doesn't have a "Bradley Com.", it's a real combat democracy.

BFV-2 and -3 are old style traditionalists.

BFV-4 is an anarchical vessel. They do what they want and have no council or commander.

"Platoon Leader" is a mini-king, he carries a globus cruciger (see his sign). Likes when they call him Platoon King.
"Platoon  Sergeant" is a half-king, with same globus cruciger but half-empty. Hates when chess and card players call him Platoon Queen.

"Radio Operator." Often gets hit by electricity, so his sign is a lightning.

"Forward Observer". Has no rear window, can look only forward. That's why they tease him "Forward" rather than just "The Observer".
As the eyehole in the armor is narrow, usually can see nothing even forward. That's why his sign is a stroke out eye.

"Combat Medic". Can pray and hope. Carries a bag with corresponding symbols.

"Squad Leader". Wants to be a Squad King, too, but still has to carry a globus cruciger with only one stick.
Because he is an infantry, not a cavalry. If he had a horse, could have a full one.

"Team Leader" secretly cosplays the "Platoon Sergeant" when he doesn't see. So, carries a plain globus to hide it quickly.

"Grenadier". Cosplays XVII century. As nowadays everyone has grenades, feels jilted. The draft officer promised that all grenades are only his.

"Rfleman". Like the previous one is, this one is Musketeer. Is sure that M in M4 is for Musket.

"Automatic Rifleman". Upgraded version of the previous one. Can be grown when you upgrade Barracks up to Advanced Barracks.
This requires "Automaton" and "Machine" skills, so he is Automatic, while his gun is Machine.

***

A missile can be used as a beam delivery.

[JoeSchmuckatelli]

3 hours ago, DDE said:

It's worse. I've recently gotten bogged down in... a different kind of minutae.

I'm coming to the realization that this is counterproductive. So here's why everyone should switch to America's four-tank squads...

Three observations

1.  I'm stunned the Army is still using M4A1s - my experience with Iraq showed that the shorter barrel adversely impacted muzzle velocity, terminal ballistics and mission accomplishment.

2.  As a former tanker: the US style of 4-vehicle platoons (two sections of two tanks able to support one another and move independently) has always seemed far superior to the 3-tank platoon model (Soviet).  I know what it is like to be a single tank sitting by yourself out in the open: you feel all the limitations of the platform.  With your wingman next to you, you're ready for offensive action, and each platoon can do two things at once.  Flexibility is power. 

3. As a former Marine Infantry officer, I agree with all of the critiques listed above.  We had a real advantage in our Vietnam-era vehicles (that the AF failed to identify).  Our AAVs offer 18 troop spaces.  Given the average Marine Rifle Squad is 13 men, the remaining 5 (well 7-9) spaces in the vehicle were used successfully to keep the squad's attachments (machine-gun teams or assault/rocket teams) with their squads.  I can only imagine how frustrating it must be for an Army LT to try to do Combined Arms mission planning with vehicles that don't let him keep his mission-tailored squad assignments together.  There's a real risk of losing Tempo if the squad leaders and other NCOs have to spend the first moments after deployment finding people, rather than attacking the objective.

We almost had a replacement with the AAAV - but trying to build a ground-combat capable vehicle that protects the Navy by being over-the-horizon deployable and self-ship-to-shore capable proved... expensive.

 

Which reminds me: a 4th observation - Starship Troopers' individual ablating eggs for dropping into the battlespace (an analog of paratroops) was always interesting to me.  Cook did some interesting things in his Sci-Fi books, but a whole lot of authors regularly fail to spend much time on how the Navy (space battle cruiser, whatever you call it) gets the infantry on the ground.  If we're gonna have a good space war... I really want the author to spend some thought on how they're going to deploy the 'boots on the ground' aspect of combat.

 

 

Edited July 21, 2020 by JoeSchmuckatelli

[Hannu2]

On 7/11/2020 at 5:30 PM, Spacescifi said:

How powerful is one ton of antimatter?

According to one calculation that is 43000 megatons, with a incinerate to burn damage of a 500 kilometer radius!

To put that in perspective, the karman line is about 200 kilometers up... so if we light up one of these 1 ton AM bombs EVEN in LEO the Earth below is bound to get a massive fireball anyway.

You seem to overestimate power of antimatter bomb. 1 t of antimatter annihilated with 1 t of matter produce 1.8E20 J. If it is distributed evenly on sphere with radius of 500 km it gives 58 MJ/m^2.

 

On 7/11/2020 at 5:30 PM, Spacescifi said:

A single one ton AM bomb missile would either annihilate or damage most of any fleet that lacks fictional shields. Armor matters not.

Heating 20 C water to 100 C and evaporating it consumes 2.6 MJ/kg. Water shield of 22 kg/m^2, or 22 mm thick layer, could absorb 58 MJ/m^2. Practically absorption coefficient of gamma radiation is low and need thickness of meters, but if you think technological level able to refine and handle tons of antimatter it is not hard to believe that they are able to take material from asteroids to build shields needed to protect themselves. Thick armor would not overheat and be expendable.

 

On 7/11/2020 at 5:30 PM, Spacescifi said:

Do spread ships out one by one.. like really far, maybe 2000 kilometers.

If you use large antimatter driven spaceships you probably intend to travel at least interplanetary distances. 2000 km is pretty much nothing in such scale. For example, a sphere with radius of 400000 km (Moon distance) can contain about 64 million spaceships with distance of 2000 km.

Antimatter bomb could be usable to destroy some kind of single important local base or station, but you would need one bomb per ship. Or practically much more, if ships had protection measures, which they would certainly have if there were risk to be attacked.

 

[kerbiloid]

2 hours ago, Hannu2 said:

You seem to overestimate power of antimatter bomb. 1 t of antimatter annihilated with 1 t of matter produce 1.8E20 J. If it is distributed evenly on sphere with radius of 500 km it gives 58 MJ/m^2.

1.8*10²⁰ J / 4.2*10¹⁵ J ~=43 000 Mt

1 Mt, aerial, 10 kPa radius (nominal destruction radius) ~= 14 km.

(43 000 / 1) ^1/3 * 14 ~= 490 km (rough estimation)

[Hannu2]

8 minutes ago, kerbiloid said:

1.8*10²⁰ J / 4.2*10¹⁵ J ~=43 000 Mt

1 Mt, aerial, 10 kPa radius (nominal destruction radius) ~= 14 km.

(43 000 / 1) ^1/3 * 14 ~= 490 km (rough estimation)

Thickness of significant atmosphere is at most few tens of kilometers. Approximations of aerial explosion are totally useless in space and also in atmosphere if bomb is big enough. If I remember correctly those approximations failed already in 50 Mt tsar bomba explosion, because most of energy "leaked" straight to space through thin atmosphere.

It is extremely difficult to make effective area destruction effects in space. It would need neutron stars or other exotic and practically impossible power sources.

 

[kerbiloid]

4 minutes ago, Hannu2 said:

It is extremely difficult to make effective area destruction effects in space.

In space it's easier as nothing absorbs the radiation between the explosion and the target, so you just need to estimate the required energy per area to cause damages.
And this depends on the ship construction, so can vary in wide range. But for exact ship you can.

In air - of course, it's a rough estimation, as I said.

Edited July 21, 2020 by kerbiloid

[Hannu2]

8 minutes ago, kerbiloid said:

In space it's easier as nothing absorbs the radiation between the explosion and the target, so you just need to estimate the required energy per area to cause damages.
And this depends on the ship construction, so can vary in wide range. But for exact ship you can.

As I showed, energy needed to cause damage is enormous. 1 t of antimatter, which needs technomagic level technology and we can not even know is it ever practically possible, can not cause damage from 500 km away, which is very short distance in space. Of course you could attack against ISS with large antimatter or even nuclear bombs, if you were a commander of supercivilization's space force, but if you assume about same level of defensive technology, practically possible radiation pulses are easy to absorb under credible conditions (for example separation of thousands of kilometers between space fighters).

[kerbiloid]

52 minutes ago, Hannu2 said:

can not cause damage from 500 km away,

Iron hull.

Half-value layer ~3 cm (depends on energy).

So, ~10 cm thick iron absorbs almost all thermodynamically significant energy.

Iron evapouration heat ~6.3 MJ/kg (google), density 7800 kg/m³.

0.1 * 6.3*10⁶ * 7 800 ~= 5*10⁹ J/m² to evaporate as thick armor layer as you can and hit the ship with the shockwave.

sqrt(1.8*10²⁰ J / (4 * pi * 5*10⁹ J/m²)) ~= 54 km.

The ship hull will be mechanically destroyed at ~50 km distance.

***

The gas cloud here is 7 800 kg/m³ dense and ~3 000 K hot, molar mass 56*10^-3 kg/mol, layer thickness 0.1 m, monoatomic.

Inner energy of the gas ~(3/2 * 7 800 * 3 000 * 8.3144 / 56*10^-3) * 0.1 ~= 4 * 10⁹ J/m³ * 0.1 m ~4*10⁸ J/m².

If take a carrier-sized ship as an example, mass ~= 100 000 t, length ~=250 m, width/height ~= 50 m, then its mass/cross-section area ~=10⁸ / (250*50) ~= 8000 kg/m².

If ~25% of the gas energy pushes the ship, it's ~0.2 * 4*10⁸ / 8 000 ~= 10 000 J/kg of kinetic energy.
Or 100+ m/s of sudden delta-V.

The gas thermal velocity ~sqrt(3 * 8.3144 * 3 000 / 56*10^-3) ~= 1 100 m/s.
The gas layer thickness ~0.1 m, so the dissipation duration ~= 0.1 / 1 000 ~= 10^-4 s.

Acceleration ~100 / 10^-4 / 9.81 ~= 100 000 g.

So, the ship will be thrown away with 100 000 g overload, and everything inside will get pulped

***

To decrease the overload down to ~1..10 g, it should get only 10 000..100 000 th of that amout of iron vaporized.

So, to be sqrt(10 000.. 100 000) = 100...300 times farther.

100..300 * 50 = 10 000 +/- 5 000 km.

So, the inertial damages will take place at thousands of kilometers distance.

***

Human body: LD100 ~500 rem.
For gamma 1 rem = 1 rad, so 500 rad. Or 5 Gr.

5 Gr = 5 J/kg.
For 70 kg body, at 0.25 m² projection, it requires 5 * 70 / 0.25 ~= 1 400 J/m² of gamma radiation flow.

1.8*10²⁰ / 1 400 / (4 * pi) / (k * R²) ~= 10¹⁶ / (k * R²) = 1

k * R² ~= 10¹⁶ m².

At 1 000 km distance you need k ~= 10¹⁶ / (10⁷)² ~= 100 ~= 6.6 half-value layers ~= 20 cm ot steel armor to get jus LD100.
To be relatively safe (several rads), you need additional k ~500 / 5 ~= 100, i.e. the armor twice as thick, 40 cm.

***

So, rough estimation for a carrier-sized spaceship is ~1000+ km.

***

As there is no sense in one bomb per heavy cruiser, an AM-armed ship will destroy allied forces in tens of thousands of kilometers radius, causing a chain reaction of their explosions.

And if place ships too close, they can't assist each other and are not a fleet.

Edited July 21, 2020 by kerbiloid

[DDE]

6 hours ago, KSK said:

What labels are outstanding at though, in my experience, (and I'm not aiming this at anyone on this thread) is giving people an excuse to look down their noses at particular stories or styles of story because 'those aren't proper sci-fi'.

We can keep the recursion going for quite a while...

[DDE]

4 hours ago, JoeSchmuckatelli said:

As a former Marine Infantry officer, I agree with all of the critiques listed above.  We had a real advantage in our Vietnam-era vehicles (that the AF failed to identify).  Our AAVs offer 18 troop spaces.  Given the average Marine Rifle Squad is 13 men, the remaining 5 (well 7-9) spaces in the vehicle were used successfully to keep the squad's attachments (machine-gun teams or assault/rocket teams) with their squads.  I can only imagine how frustrating it must be for an Army LT to try to do Combined Arms mission planning with vehicles that don't let him keep his mission-tailored squad assignments together.  There's a real risk of losing Tempo if the squad leaders and other NCOs have to spend the first moments after deployment finding people, rather than attacking the objective.

Well, sadly there is the obvious but also dubious solution: cut tge squad down to whatever the vehicle designers can manage.

Spoiler

Soviet fireteams were always essentially non-existent, but the mechanized variant of the paratroops seen above definitely took the cake )

Those USMC amphibs really are an asset. And since the missions of a rifle squad are ever-expanding, the path ahead may be bigger squads, not the smaller squads introduced post-WWII. The Corps might be entirely right about the three-fireteam squad.

4 hours ago, JoeSchmuckatelli said:

If we're gonna have a good space war... I really want the author to spend some thought on how they're going to deploy the 'boots on the ground' aspect of combat.

Well, most sci-fi boils down to some mixture of 'space parachutists' and 'space helicopters'/'space Higgins boats'. Which isn't a problem, since most of it avoids having any sort of armour or a major logistics train.

Whenit doesn't, depending on how whether we're talking tanks, or humongous mecha, it can become either 'space LCUs' or outright 'Landing Starships Tank'.

Spoiler

...but that's almost never seen in prominent media, of course.

[Spacescifi]

20 hours ago, Codraroll said:

to think of it, have you even written anything? Or are you just endlessly exploring concepts?

 

Define written.

As in actual chapters?

Or worldbuilding drafts?

I explore concepts more because it's part fun, part frustrating, learning that most all of scifi is wrong... yet at times reality can be a boon, as in the case of antimatter.

And I like how overpowered mixing reality and scifi tropes is... far greater in power than usual scifi media fare.

The more one mixes reality with scifi tropes, the more likely the result will look like some overpowered newtonian nightmare with a glass jaw (tv tropes... you probably know what the phrase means).

Which ironically and makes me laugh is that such thorough mixing will hurt even unrealistic starships.

Who even needs photon torpedos?

We can fire antimatter particle beams thousands of kilometers away at near light velocity given the same tech shown in the setting.

And going further, the fact that PLASMA beams actually weaken trek shields makes them look kinda weak.

They may as well put gatling guns on ships and fire those... they would pack a greater punch... if newtonian physics even mattered in trek on a consistent basis.

[KerikBalm]

47 minutes ago, Spacescifi said:

We can fire antimatter particle beams thousands of kilometers away at near light velocity given the same tech shown in the setting.

As already mentioned, if you are firing a particle beam at near light speed, making the particles antimatter would have a negligible effect.

Why do you insist on using antimatter where it doesn't make sense?

[Codraroll]

2 hours ago, Spacescifi said:

Define written.

As in actual chapters?

Or worldbuilding drafts?

Stories. The stuff that's left when you remove the techno-jargon. What happens, not how it happens. And, just as importantly, the characters things happen to. 

To paraphrase yourself, the more one mixes reality with scifi, the less it becomes scifi, because if you refuse to step beyond a few boundaries, the fiction part dwindles away until you're left with a long list of theoretical considerations. And if that's the direction you want to go, you're better off just studying particle physics than trying to write stories.

[kerbiloid]

It can be a philosophical inner monologue of an antimatter particle of that beam. Full of drama, describing its origin. Its thoughts about the inevitable meeting with the target. And its emotions when the shot had missed, so the particle is now endlessly flying to the great nowhere.

[magnemoe]

2 hours ago, KerikBalm said:

As already mentioned, if you are firing a particle beam at near light speed, making the particles antimatter would have a negligible effect.

Why do you insist on using antimatter where it doesn't make sense?

Agree, antimatter weapons make sense as an fie dust cloud or even gas at standard velocities. Close to light speed particle beams standard matter works just as well and is a bit easier to work with. 
Big bombs, nuclear bombs are very safe, unlike antimatter who goes off if anything goes wrong, they are also fairly rugged and cheap. 
The cloud would be effective as an area effect weapon. Nice against missile swarms distributed sensors or other cases where you have lots of small targets 

An second use is as rocket fuel as its the best. Think it would be very nice for missiles as engine don't have to be gigantic. The danger of antimatter is less relevant for missile but is relevant for the launch platform. 

Edited July 22, 2020 by magnemoe

[KSK]

43 minutes ago, kerbiloid said:

It can be a philosophical inner monologue of an antimatter particle of that beam. Full of drama, describing its origin. Its thoughts about the inevitable meeting with the target. And its emotions when the shot had missed, so the particle is now endlessly flying to the great nowhere.

And if the gunners / targeting computers aren’t much good:

”Curiously, the only thing to go through the mind of antiproton OnePointEight x Ten-to-the-Fifth was “oh no - not again.”

[kerbiloid]

"Antiparticle. When the whole world is opposite to you."

[magnemoe]

16 hours ago, Hannu2 said:

Thickness of significant atmosphere is at most few tens of kilometers. Approximations of aerial explosion are totally useless in space and also in atmosphere if bomb is big enough. If I remember correctly those approximations failed already in 50 Mt tsar bomba explosion, because most of energy "leaked" straight to space through thin atmosphere.

It is extremely difficult to make effective area destruction effects in space. It would need neutron stars or other exotic and practically impossible power sources.

 

http://www.projectrho.com/public_html/rocket/spacegunconvent.php#shapedcharge
Here you have your plasma weapons
However its more like an anti tank shaped charge but using nuclear weapons rather than chemical explosives. 

An small version has a couple of km standoff distance. An large one 50 and an large advanced one up to 1000 km. 
Bomb pulsed x-ray lasers is much in the same category. Probably not more range than the advanced but should be lighter and might hit multiple targets. 

This is relevant as you will need to kill missiles farther out. Enemy might also set off a missile at extreme range to damage your sensors and point defense weapons who will be less protected than the hull. 
 

[KSK]

1 hour ago, kerbiloid said:

It can be a philosophical inner monologue of an antimatter particle of that beam. Full of drama, describing its origin. Its thoughts about the inevitable meeting with the target. And its emotions when the shot had missed, so the particle is now endlessly flying to the great nowhere.

“Hath not an antiproton substance? Hath not an antiproton charge, spin, dimensions, gauge, field interactions! Born of the same singularity, used for the same weapons, subject to the same laws, given mass by the same means, warmed and cooled by the same enthalpies and entropies as a proton is? If you collide with us do we not annihilate?“

Edited July 22, 2020 by KSK