Pulsed Fusion Characteristics

Figure 1: Fusion reaction rate coefficients Thermonuclear fusion is governed by the rate coefficient 〈σv〉 for fusion reactions, which for a particular reaction is a function only of (ion) temperature T . For the D-T reaction its value is roughly 5× 10−22 m−3s−1 at T = 20keV, the typical operating temperature of proposed reactors. The rate peaks a factor of only 2 higher at about 60keV temperature, so it is not generally worth trying to go to higher temperature. For other fusion reactions the rate is at least 10 times less; so they are much more difficult. Pulsed reactors consider a single complement of fuel which is compressed, heated, reacts and then exhausts. Net energy production requires that sufficient fraction of the fuel experiences a fusion reaction, otherwise the energy consumed in compressing and heating the fuel will surpass the fusion energy released. In some approaches to pulsed fusion, such as Magnetized Target Fusion, it is supposed that essentially the whole of the fuel is heated. In others, only a fraction of the fuel (the “hot spot” in laser fusion) is supposed to be heated, and its energy yield is supposed to heat