A few thoughts on nuclear fusion (esp. magnetic confinement approach). Im no expert, I just want a good discussion going and a lot of "prove me wrongs" since im just learning about all this stuff! My background is astrophysics and cosmology so as for the material sience in this post, im a total beginner. As for the physics parts, e.g. everything that has to do with Lorentz Force, MHD, I can help you understand.
Part 1
- magnetic confinement (tokamak/stellerator) has shown to be superior over inertial confinement when in comes to applicability for a future fusion power plant (area of heat + cooling systems, confinement time, amount of fuel)
- the stellerator is a highly attractive idea because the helical magnetic field results from outer coils rather than from a contribution of a plasma current, yet poses enormous difficulties when it comes to partial replacements or manufacturing of the superconducting coils (the cassette idea for DEMO looks good to me)
- the D+T reacting is superior over all other possible nuclear fusion reactiongs (like D-D) because it has the highest nuclear cross section in a temperature interval which is attractive (~150*10^6 K); higher T means more difficulties for surrounding materials and the magnetic field
- MHD is extremely complicated when it comes to different phenomena, e.g. ExB drift
- At some point during plasma heating, additional heating like ECRH (can also control plasma instabilities) or NBI (can contribute to the current drive, more later) is required because (in a tokamak) the ohmic heating power goes with the inverse temperature as P~(1/T)^(3/2) and the alpha particles from the fusion products (D+T->He(3.5Mev) + n(14.1 MeV) will of course contribute to the heating at later, hotter times when they can be produced from the first fusion processes
Part 1
- magnetic confinement (tokamak/stellerator) has shown to be superior over inertial confinement when in comes to applicability for a future fusion power plant (area of heat + cooling systems, confinement time, amount of fuel)
- the stellerator is a highly attractive idea because the helical magnetic field results from outer coils rather than from a contribution of a plasma current, yet poses enormous difficulties when it comes to partial replacements or manufacturing of the superconducting coils (the cassette idea for DEMO looks good to me)
- the D+T reacting is superior over all other possible nuclear fusion reactiongs (like D-D) because it has the highest nuclear cross section in a temperature interval which is attractive (~150*10^6 K); higher T means more difficulties for surrounding materials and the magnetic field
- MHD is extremely complicated when it comes to different phenomena, e.g. ExB drift
- At some point during plasma heating, additional heating like ECRH (can also control plasma instabilities) or NBI (can contribute to the current drive, more later) is required because (in a tokamak) the ohmic heating power goes with the inverse temperature as P~(1/T)^(3/2) and the alpha particles from the fusion products (D+T->He(3.5Mev) + n(14.1 MeV) will of course contribute to the heating at later, hotter times when they can be produced from the first fusion processes
