Plasma is a relatively common weapon in science fiction, with weapons that fire magnetically-bound superheated plasma or melee weapons that hold plasma in a containment field to burn through just about anything.
Plasma in real life isn't as useful as a weapon. It loses heat quickly when fired (assuming we find a way to keep the plasma from just expanding into hot air log before it reaches the yarget) or is almost as deadly to the wielder of a plasma melee weapon as to it's target. So my question is: assuming technical problems can be overcome, what would be the most efficient way to use plasma as a weapon?
My own thoughts so far:
"classic" plasma fired from a gun held by some pseudo-magic magnetic core. Even when keeping it together like this it'll lose a lot of heat while traveling. Perhaps if you managed to increase the magnetic force and make the plasma bolt incredibly tiny you could alleviate some of this.
Contained plasma. The plasma is put in an insulation shell to prevent as much heat loss during travel. Upon contact the shell breaks and unleashes the plasma on the target. Potentially you could pressurize the plasma in the shell, upon breaking the plasma would burst forth from the hole similar to a shaped charge, although I'm not sure how much plasma would spray into/on the target and how much would just propel the shell and plasma away from what it hit. Probably the best bet would be to pressurize it only a bit so the plasma jet upon shattering wont exceed the speed with which it impacts a target.
melee weapons with plasma-contained edges. The "classical" form where most of the blade is a containmentfield with a lot of plasma in seems too dangerous for the wielder and very energy inefficiënt. A better way would likely be to have a "normal" melee weapon where its edges are formed by a containment field and plasma. The thinness, heat and how this plasma edge reforms after each strike would be the key here without requiring so much heat to cut something that striking an enemy would cause a water vapour explosion and heated gasses to burn the wielder.