Can Radiation Losses Be Recovered in Nuclear Fusion for Net Power Gain?

[TESL@]

Hello,

After researching on many kinds of confinement methods and most promising reactions, (aneutronic fusion etc.) I saw almost every paper complained about radiation losses as the greatest problem preventing net power gain. And except Tri-Alpha Energy and LPP (Dense Plasma Focus) companies, nobody seems to be caring about recovering these losses. Since degenerate plasma is not practical aside from inertial confinement, the radiation must either be harvested or sent back to the plasma. So, why don't they just generate electricity from electron cyclotron waves by a rectenna array, and in return heat the ions by ICRH? What about bremsstrahlung? Is there no possibility but inefficient photoelectric converters?

Thank you.

 

[mfb]

So, why don't they just generate electricity from electron cyclotron waves by a rectenna array

The radiation is not coherent, and I don't think radio waves make up a significant part of the emitted power.

The harsh radiation and temperature conditions also limit the number of things you can place next to the plasma. It is hard enough to find some material for the first wall, even without additional functionality.

 

[TESL@]

Thank you for replying. Anything about bremsstrahlung?

edit: Inverse-bremsstrahlung is possible http://link.springer.com/chapter/10.1007/978-1-4684-8416-8_20

 

[the_wolfman]

After researching on many kinds of confinement methods and most promising reactions, (aneutronic fusion etc.) I saw almost every paper complained about radiation losses as the greatest problem preventing net power gain. And except Tri-Alpha Energy and LPP (Dense Plasma Focus) companies, nobody seems to be caring about recovering these losses. Since degenerate plasma is not practical aside from inertial confinement, the radiation must either be harvested or sent back to the plasma. So, why don't they just generate electricity from electron cyclotron waves by a rectenna array, and in return heat the ions by ICRH? What about bremsstrahlung? Is there no possibility but inefficient photoelectric converters?

Both Tri-alpha and Lpp are interested in p-B fusion. p-B fusion requires orders of magnitude hotter temperatures than D-T fusion. The power radiated by Bremsstrahlung increases with both temperature and ion charge. For p-B fusion Bremsstrahlung is a potential show stopper for p-B fusion. Its a huge issue!

In a burning D-T plasma, 80% of the energy is lost via the neutron. This is the lions share of the energy, and the focus should be on capturing this energy efficiently (neutrons are also important because they are used to breed tritium). The remaining 20% of the energy is lost via various conduction, convection, and radiation mechanisms. I expect that various turbulant losses will dominate the remaining 20%. Turbulance dominates the heat loss in modern high performance tokamaks and stellarators.