sublight engines

[Splitsecond]

I work as an accelerator physicist, so I know a lot about hyper-velocity charged particles and I can tell you that all you need is an overall charge, any charge will do, but the more mass you have per charge the harder it is to accelerate the mass.

[thekillman]

i'm not a scientist.

my point is: ions are just ions. they are matter that is ionized and then accellerated. plasma is superheated gas that has free nucleae. because it is superheated, it delivers thrust. add electric accelleration and you have even more thrust.

[Character]

But you still have to heat the gas for it to become plasma, in other words apply energy, which you can do equaly well to ions. So i dont see why plasma would be more powerfull. Although, talking about SG tech, while plasma implies that you somehow energize, accelerate and use the plamsa to push the craft, ions as you said arent neccesarily gas, so their use for propulsion could be drasticly different and so could be much more powerfull. Like, a simplest idea would be that the ions are used to apply a stronger/more efficient charge to energize the plasma. Or maybe they have more exotic properties, like whatever is used in the NIGs.

[thekillman]

or use an exothermal reaction for the gas.

[Splitsecond]

i'm not a scientist.

my point is: ions are just ions. they are matter that is ionized and then accellerated. plasma is superheated gas that has free nucleae. because it is superheated, it delivers thrust. add electric accelleration and you have even more thrust.

An electrically charged particle of group of particles will accelerate towards a point with opposite charge. Say for example you're using electrons:

electron (-)
cathode l+l
electrode l-l
acceleration >>
deceleration <<

l-l >> (-) >> l+l << (-) << l-l >> (-) >> l+l

The problem here is that there is no net acceleration, so you shield the electrons from the decelerating part with the use of a Faraday cage

Faraday cage =


l-l >> (-) >> l+l======l-l >> (-) >> l+l

The thermal expansion of plasma is nothing compared to the acceleration you can get from an electric field. The important factors are the electric field strength between the points, the charge on the particles and the mass of the particle group.

And there you have accelerator physics 101.

[thekillman]

i got the accelleration part, thank you.

my point is: before being plasma, you can use some reaction (say, igniting rocketfuel) to create plasma. seeing as rockets have use, it creates tons of thrust. the idea is that you massively enhance the thrust by electric accelleration.

[Splitsecond]

No, there's no point. Modern accelerators get particles up to nearly the speed of light in relatively short distances. Ions are cheaper to accelerate to very very high velocities because lower mass particles radiate their energy away faster when going round a bend. LHC will accelerate iron ions once it starts working again. The accelerated particle beam is not a beam, it is a train of bunches, because microwaves are used to accelerate the beam. A surfer is accelerated at the front of the wave, yet is decelerated if he's behind the wave. With microwave generated acceleration, you produce a wave, which accelerates those at the front and decelerates those behind, this causes the particles to bunch. Plasma from a reaction would be a relatively continuous stream, so you would lose as much energy as you would gain when the plasma starts to bunch. Incidentally plasma driven acceleration may be the future of accelerator physics, but you just use the plasma to accelerate the ions.

Also I am sorry if you already know this and think it's slightly condescending but this is my bread and butter and I love explaining it to people.

[thekillman]

nono it makes sense. but why not scrap microwaves and use electric accelleration alone? or am i mixing up alot of things?

[Splitsecond]

Electric acceleration is commonly done using microwave cavities now-a-days, although strangely it's called RF (radio-frequency). The EM wave creates the electric potential that accelerates the beam.

[SavetheGate]

A naquadah generator would be waaaay too powerful for a 302... I think

[thekillman]

Electric acceleration is commonly done using microwave cavities now-a-days, although strangely it's called RF (radio-frequency). The EM wave creates the electric potential that accelerates the beam.

so using a Cathode and Anode is different from the microwave thingey?

then plasma would be done best by C/A accelleration.

[Splitsecond]

so using a Cathode and Anode is different from the microwave thingey?

then plasma would be done best by C/A accelleration.

It's the same principle but much, much better. The C/A acceleration method is just to get things started, like pushing a car, it wouldn't be useful to just use that.

[thekillman]

so for plasma its the only possible way, but for ions the microwave thing is better?

[Splitsecond]

so for plasma its the only possible way, but for ions the microwave thing is better?

No you can do the same with plasma, but it should be started at a standstill ie cold otherwise you just waste the energy it had at the beginning when bunching the plasma together. Protons is hydrogen plasma and a positive hydrogen ion.

[General_Finley]

I am thinking either ion thrusters or Bussard ramjets biult with some help biulding them from the asgard, although it they could use some kind of fusion drive.