Physics of spin-polarized plasmas

If the nuclear spins in a fusion reactor are oriented, or polarized, in an appropriate manner, then the nuclear reactions are modified in such a way as to enhance the performance of the reactor. The methods by which the spins can be polarized and the various difficulties connected with these methods are discussed. The processes by which the polarization can be lost owing to various physical processes in a confined plasma are assessed. The different polarization modes of the plasma ions are applicable to the different nuclear reactions, D–T, D–3He and D–D. The benefits for reactor performance of these modes are discussed. It is concluded that on the basis of current knowledge, the possibility of achieving polarized spin in a fusion plasma cannot be ruled out and that the physics of such plasmas is well worth pursuing both for its intrinsic interest and for its benefit to fusion. Further, detailed calculations of the modification of the D–T nuclear reaction produced by spin polarization are given, as well as calculations of the depolarization rates for physical processes in a confined plasma. Finally, a kinetic description of a polarized plasma is outlined which generalizes the normal kinetic description of a plasma.