Rail Gun Propulsion: Perverting a Rail Gun Into a Rocket?

[schonovic]

Is it possible to pervert a rail gun into a rocket? I'm understanding that plasma conducts electricity. If i could supply a rail gun with constant current and send in a constant feed of hot plasma into the rail gun would the machine send out plasma at high enough speeds to be used as a rocket engine?

 

[Bobbywhy]

Have you checked out existing plasma propulsion systems yet? There are several mechanisms already developed. Do any of these match your description?
http://en.wikipedia.org/wiki/Plasma_propulsion_engine

 

[schonovic]

Bobbywhy

No, none of those are what I am describing. I'm talking about a regular rail gun except instead of a solid round being propelled to high velocities I'm having heated plasma propelled to high velocities. A constant current being applied to the rail and a constant supply of plasma being fed into the system. What I'm asking is will this work? Will a regular rail gun propel plasma the same way it propels a solid round?

 

[etudiant]

In theory, the rail gun would accelerate the plasma, maybe even more efficiently than a slug.
In practice, the plasma needs to be confined and may not touch the power leads for the rail gun, lest the propulsion effect get short circuited.
Solving those problems may drive you back to the approaches Bobbywhy has noted above.

 

[schonovic]

Thanks etudiant and thank you Bobywhy. I'll refer to your help.

 

[Lsos]

I'm sure your concept would work, but why have a whole separate rail mechanism accelerating the plasma, when the plasma's heat and pressure already do this? And thus you have the aforementioned ion thruster...

 

[schonovic]

Lsos
I just thought it would dramatically increase thrust capacity.

 

[Danger]

You could use a rail gun to serve as the first stage of a rocket-propelled device which would then ignite the second stage at the appropriate time. It would eliminate having those pesky boosters falling into the ocean.

 

[Deotheophilus]

your idea is sound and there is some existing tech however this system would require HUGE amounts of energy to operate at anything approaching thrust capacity, so if you have unlimited power supply then sure, but in a practical application standard solid or liquid state rocket fuel will offer the most force per pound and thus be the most efficient for a rocket (chemical energy storage is the best known so far), that said if you can mount your system to the ground, say for a plasma weapon or a cutting tool, then you might have something that could function... perhaps even powering it with solar or wind... haha you could have a green gun...

 

[Lsos]

Deotheophilus, "standard" chemical rockets might be most efficient when it comes to thrust/energy, but they most certainly are not when it comes to thrust/mass. Since mass is often the limiting factor once in space, a brute "force/ pound" approach is not going to give you the most speed.

 

[Deotheophilus]

I'm not arguing that for slow long distance travel (E.G space) something that requires minimal fuel, such as the high energy plasma thrusters disused here https://en.wikipedia.org/wiki/Plasma_propulsion_engine however the previous article claimed that these were not what was in mind, instead it is assumed that by rocket schonovic intends this as a on Earth or similar body weapon propellant, and in this case a chemical rocket will provide more energy/mass than you could hope for in any electric storage system I know to exist today, because of this my statement stands, a chemical rocket will still offer a more efficient option, in Layman's terms "More Bang for Your Buck"... (this might account for the reason NASA and now SpaceX use chemical thrusters to achieve escape velocity and only switch to ion thrusters when in the vacuum of space while powering it with the photoelectric effect) further thrust/energy advantage would not be necessarily true of a chemical rocket, they are merely capable of storing more energy/mass...