https://arxiv.org/abs/2205.03299
https://www.sciencealert.com/scientists-suggest-earth-s-core-could-be-in-a-superionic-state
"Self sustaining dyanmo" & "superionic plasma"
Im sure everyone will disagee but superionic plasma has to form a toroid to create the quadrupoles on our planet and sun. If it forms a toroid it must also form a z pinch. If it forms a z pinch its a seperate plasma flow to the toroid. Let the toroid form a self sustaining dynamo from the superconducting superionic plasma and tap the super compressed plasma energy in the z pinch to rotate the generator. As long as you dont slow the reactor down by stalling it by exacting to much power the self sustaining dynamo will keep producing the z pinch. And the z pinch will keep the reactor turning. How much input energy is required is a complete unknown, how much power can be extract is a complete unknown. Hence the need for R&D, but every time you convert energy from 1 form to another or transfere energy from 1 medium to another you lose energy. Im not transfereing energy from plasma to water tho the walls of the reactor. So it will inevitable be more efficent than a tokamak.
Not to mention the fact plasma expands at a far greater rate than steam does, as shown in this paper.
https://www.cambridge.org/core/journals/journal-of-plasma-physics/article/an-alfvenic-reconnecting-plasmoid-thruster/F296E45CC504E8FF2586EA79117E2514
Essential that means you use less volume of plasma to generate the same amount of thrust.
The same is true for burning hydrocarbons and oxygen. You can look up the terminal velocity of a craft using hydrocarbons, eventually the craft out runs the speed of expansion.
It shouldnt take a rocket scientist to figure out the plasma in the polidal jets of say a pulsar is going to expand faster than a rocket. You can read about it in the paper or multiple articles on the internet. Search for solar flare thruster and you should find plenty
Just because a particular power source, is extremely complicated, and perhaps, not well understood yet. Doesn't mean that you can start believing that it will be a source of unlimited energy (free energy), i.e. like a perpetual machine.
I get the impression, that you seem to think, that as long as this mechanism, is NOT abused. I.e. That too much energy in one go (or continuously), is NOT allowed. You can travel for huge distances, using this energy source, unlike limited, one-use power sources, such as batteries or burning rocket fuel (and ejecting it), to create motion, in space rockets.
Some theoretical energy sources, such as fusion energy (but also Nuclear fission types), can be expected/calculated, to have a huge amount of energy, which can be extracted, with some loss of mass, with the fuel materials (I.e. Einsteins's E = MC^2).
But in general, energy sources, based on some peoples ideas on how 'free energy', 'perpetual motion machines' and possibly other similar ideas. Are widely considered to be unproven (no experiments showing them working, except some suspected scam experiments, with hidden batteries/motors or secret mains connection wires, etc). have been demonstrated, as far as I'm aware.
Also, scientifically, they are considered, somewhat or fully, impossible. Since they would defeat a number of fundamental laws of Physics, such as conservation of energy, E = MC^2, making energy/matter out of nothing, etc.
If I'm mistaken, and that is NOT what you think. Then without Fusion, Fission, big tanks of rocket fuel, relying on getting enough solar energy with solar cells or relying on conservation of momentum, when the space vehicle is traveling at enough speed. Where exactly is any energy needed to power the space ships systems and/or CHANGES in speed, going to come from ?