The Heavy Ion Inertial Fusion Program is the principal part of the Inertial Fusion Energy Program in the Office of Fusion Energy of the U.S. Department of Energy. The emphasis of the Heavy Ion Program is the development of accelerators for fusion power production. Target physics research and some elements of fusion chamber development are supported in the much larger Inertial Confinement Fusion Program, a dual purpose (defense and energy) program in the Defense Programs part of the Department of Energy. The accelerator research program will establish feasibility through a sequence of scaled experiments that will demonstrate key physics and engineering issues at low cost compared to other fusion programs. This paper discusses progress in the accelerator program and outlines how the planned research will address the key economic issues of inertial fusion energy.

Target physics imposes requirements on the design of inertial fusion drivers. The influence of beam propagation in near vacuum fusion reaction chambers is evaluated for the relation between target gain and the phase-space requirements of heavy-ion accelerators. Initial results suggest that neutralization of the ion beam has a much greater positive effect than the deleterious one of beam stripping provided that the fusion chamber pressure is

Induction acceleration is one of two principal approaches for producing ion beam for heavy-ion inertial fusion. This approach was first suggested by the late Denis Keefe of Lawrence Berkeley Laboratory and is the main approach of the US heavy-ion-fusion program. Induction accelerators have the ability to handle high beam currents; therefore, accumulation rings or storage rings are not required. This paper reviews the target and accelerator considerations that are important for the design of induction accelerators for fusion. These considerations, including some important assumptions, have led to a standard induction accelerator concept; however, a careful examination of the assumptions and considerations shows that many of them are not truly fundamental. Through improvements in technology, changes in design, and alternate ways of focusing beams, it appears possible to circumvent or relax the constraints imposed by the standard orthodoxy. If it is possible, it will lead to induction accelerators that are more efficient and less costly than the standard concept.

Inertial-fusion targets have been designed for use with heavy-ion accelerators as drivers in fusion energy power plants. We have made an initial survey of target gain versus beam energy, power, focal radius, and ion range. This provides input for understanding the trade-offs among accelerator designs.

Inertial-fusion targets were designed for use with heavy-ion accelerators as drivers in fusion energy power plants. In the interest of providing inputs for understanding the trade-offs among accelerator designs, an initial survey was carried out regarding target gain versus parameters of relevance. This was done in two stages, firstly target gain was related to the beam energy, power, focal radius, and ion range. Secondly, a more comprehensive discussion was made by posing target gain constraints on the beam-occupied phase-space volume of the linacs. This latter discussion had included some rather simplified models of accelerator final focus and beam transport in near-vacuum fusion reaction chambers. Some further analyses of the basic assumptions of this summary are also described.