![]() Much more promising are much smaller devices using highly nonequilibrium, pulsed regimes, such as the so-called dense plasma focus (DPF). Construction of the International Toroidal Experimental Reactor (ITER) (left). Model of ITER reaction chamber. ![]() From the standpoint of actually realizing fusion as a commercial power source, though, the ITER looks very much like a dead end. In my opinion, the ITER is valuable primarily as a platform for plasma research, technology development and as a means of supporting an ecosystem of scientists and engineers working in relevant areas. Today the scene is dominated by the gigantic International Thermonuclear Experimental Reactor (ITER) project, now under construction in Cadarache, France. using magnetic fields to counteract its enormous force of expansion. The first strategy is to confine the hot plasma in a “magnetic bottle,” i.e. The effort to solve this problem has led to two very different strategies. Without mechanisms to confine it, the heated fuel will expand explosively and quickly lose the density required for significant numbers of reactions to take place. Million-degree temperatures generate astronomically high pressures. Predicting and controlling the behavior of plasmas at high energies is a formidable task, even with the help of the fastest supercomputers. For the physicist a paradise, or a nightmare, depending on how you look at it. There are collisional and quantum effects etc. Plasmas exhibit an enormous variety of different types of waves and oscillations they emit electromagnetic radiation, they display collective, self-organizing properties. One speaks of “magneto-hydrodynamics.” Plasma behavior is by its very nature highly nonlinear. Their motion gives rise to electric currents and magnetic fields, which in turn act upon the whole plasma. Already at much lower temperatures, the fuel turns into a plasma: the electrons (or most of them) are no longer bound to the nuclei, but swarm around more or less freely, as do the nuclei, albeit still pushed and pulled around by the forces of attraction and repulsion among them. Much more than heating is involved, though. This is also the origin of the term thermonuclear weapon to denote what is more popularly known as a “hydrogen bomb.” In the fusion business, until now, one speaks mainly of thermonuclear fusion: fusion reactions induced by raising the fuel to million-degree temperatures. New approaches are evidently needed, in fact, a new paradigm, which one might call the “non-thermal paradigm.” Plasma physics: paradise or nightmare? Meanwhile, after well over half a century of worldwide efforts, and investments ranging into the tens of billions of dollars, it is still not possible to predict with any degree of certainty when power stations based on the D-T reaction might actually come online. ![]() Unfortunately, hydrogen boron reactions occur in significant numbers only under very extreme physical conditions – even much harder to realize than the deuterium-tritium (D-T) reaction, which has until now been at the focus of fusion research. In the previous installment of this series, Jonathan Tennenbaum explained how the nuclear fusion reaction between hydrogen and boron could provide a basis for highly-efficient, radioactivity-free generation of electricity, with virtually unlimited reserves of fuel.
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