Types of fusion reactors and how they work?

[Xforce]

TL;DR Summary

There are more ways to fuse atoms other than a tokamak

At the early 20th century, people can only achieve fusion by smashing atoms together via particle accelerators. That obviously outputs much less energy than input, and takes forever just to fuse a single gram of hydrogen to helium.
Currently, speaking of thermonuclear reactors we always think of a tokamak like ITER (see the picture below)

It undoubtedly have sustained fusion and high efficiency, but I have also heard fusion methods like Z-pinch, stellarators and inertial fusion (as a proposed futuristic space propulsion). What are the other ways of achieving fusion, how do they work and what advantages/disadvantages do they have?

 

[phinds]

What are the other ways of achieving fusion, how do they work and what advantages/disadvantages do they have?

What research have you done? What have you found out so far?

 

[Xforce]

I have find out that there are mostly two methods of achieving fusion, one method i think is called MEF where you use a magnetic field to levitate the plasma, then heating the plasma hot enough (probably around 100 million Celsius) to have fusion reactions. This method is ideal to be used in power plants, combining it with thermoelectric generators. Another one is ICF (inertial confinement fusion) where you fire lasers at extremely short pulses onto a fusion pellet, and they do this doing continuously. I think it will be difficult to generate power out of this, but by adding a magnetic force to redirect the charged particles into a certain direction, it will make a great vacuum propulsion system.

 

[phinds]

Another one is ICF (inertial confinement fusion) where you fire lasers at extremely short pulses onto a fusion pellet, and they do this doing continuously. I think it will be difficult to generate power out of this, but by adding a magnetic force to redirect the charged particles into a certain direction, it will make a great vacuum propulsion system.

If it will be difficult to generate power out of this method, then why would you think it would be useful as a propulsion system? Where will you get the power to run it?

 

[Xforce]

If it will be difficult to generate power out of this method, then why would you think it would be useful as a propulsion system? Where will you get the power to run it?

Because pulse lasers are extremely powerful (those short pulses have the highest peak outputs amongst human made devices) ignition can reach higher temperature to enable things like D-He3 fusion that produce solely charged particles (of course there are D-D fusion that generate neutrons, but 95% energy is carried by charged particles) where our tokamaks can’t reach that kind of temperature. So it will be easier to redirect the flow of particles and getting higher efficiency. In fact I think the Daedalus project use this method...
The power problem can be solved by using part of the power output of the engines, to charge the capacitors of pulse lasers and the electromagnets..Especially the thermoelectric power of the neutrons, we don’t want to waste them. But I doubt the energy will be enough though (that’s what I mean difficult)

 

[phinds]

Because pulse lasers are extremely powerful

Which doesn't answer my question. Over the long haul, how do you power the lasers? You admit that the output of the engines won't be enough and of course they couldn't possibly because then you'd be creating power out of nowhere if the engines could power themselves AND drive the rocket. Where does the extra energy come from?

 

[Xforce]

Which doesn't answer my question. Over the long haul, how do you power the lasers? You admit that the output of the engines won't be enough and of course they couldn't possibly because then you'd be creating power out of nowhere if the engines could power themselves AND drive the rocket. Where does the extra energy come from?

Probably an onboard tokamak for power generation, but this means the spacecraft will be bulky, and requires to carry 3 types of fuel, deuterium, helium3 and tritium. Another method is to beam power via lasers from earth, but distance will be a limitation .

 

[artis]

Just to be clear here, a missile or a rocket or any type of flying object especially one that aims to travel long distances in space needs to be lightweight and with an engine powerful enough yet at the same time using a fuel or an energy source that is "energy dense"
By energy dense I mean a fuel for example that has a lot of potential energy for a given weight aka power to weight ratio.

A tokamak , at least the current ones are very energy/mass ineffective by this I mean the structure and cooling and all the auxiliary stuff required weighs ALOT, but the power density is rather low, that is because the plasma density that can be achieved (proposed) is also rather low. It may work for earthly commercial power goals but definitely not for space , at least not for now.
for example Iter toroidal D shaped magnets used to confine the plasma weight about 310 tons each and there are 18 of them, the central magnet used to induce current in the plasma weighs even more.
The whole structure weighs 1000's of tons.
https://www.iter.org/mach/MagnetsAlso forget about the laser fusion experiment, it's just a way for the US to test fusion physics and also simulate H bomb behavior (possibly)
To get any commercial net power one needs a fusion reactor with sufficient plasma volume/density and sufficient burn time (the time in which enough fusion events take place so that the energy given out by plasma is enough to self heat the plasma as well as provide extra net energy)
The small pellet needs to be reinserted every time after it has been imploded which takes time, then the lasers are only 20 something % efficient so enormous amounts of electricity are spent and they can't be recovered.

If this all was so easy as you @Xforce make it sound then Greta Thunberg would have never been allowed into the UN to speak because there would be nothing to speak about as our energy/waste problem would be solved.