Prediction of Net Energy Gain in Deuterium-Beam Interactions with an Inertially Confined Plasma

It is shown that deuteron beams incident on compressed, tritium-based plasma targets can undergo beam-fusion reactions at a rate greater than Coulomb scattering for a wide range of beam energies and target temperatures. As a result, energy gains of about 5 are possible. The analysis is carried out by treating the beam ions, target ions, and the electrons as separate fluids. Essential to the attainment of high gain is the inclusion of the contribution to the fusion yield from deuterons that gain scattered energy at the expense of directed energy. The results are confirmed by Monte Carlo simulations equivalent to a Fokker-Planck treatment.

Figure 1

Plotted vs time are the beam velocity, the energy gain, the beam energy density loss to the target ions, and the beam energy density loss to the target electrons. The target temperature is 10 keV. Time is normalized to the collision time for beam ions incident on target electrons.

Figure 2

The fusion energy gain as a function of beam energy for various target temperatures. Each curve is labeled by the corresponding target temperature.

Figure 3

The ratio of the energy deposited by the beam ions on the target electrons to that deposited on the target ions. For most parameters of interest, stopping is predominantly due to target ions.

Figure 4

The heating efficiency as a function of beam energy for various target temperatures. Each curve is labeled by the corresponding target temperature.

Figure 5

The gain as a function of beam energy resulting from the fluid approach and the Monte Carlo calculations.