Parisi and Ball begin with a high-level overview of human power use and the ultimate sources that can be used to provide that, then in "Energy in Numbers and Graphs" give a quantitative analysis of our future energy options, considered quite generally. Fusion is not our salvation, but is one possible component of our future energy supply mix.
Three chapters then present the core physics and engineering of fusion energy systems. A short chapter covers the basic energetics — potentials and binding energies and cross-sections — and different possible fuels — deuterium-tritium is the most plausible. Then comes a long chapter on confinement, looking at the physics of plasmas and the problems involved in holding one together for long enough, at high enough temperatures, for fusion to take place. And a chapter describes the bevy of complex engineering systems that are required for this: magnets to produce the confining fields, systems for heating the plasma, the "first wall" container, divertors for managing leaking particles and energy, tritium breeding blankets, diagnostics, and so forth.
Parisi and Ball then turn to the history of fusion research, focusing on tokamak systems. "The Past" concentrates on technological breakthroughs such as superconducting magnets, the bootstrap current, H-Mode plasmas and supercomputer simulations, but also the background politics, such as key Soviet contributions in 1956 and 1968 despite Cold War tensions. "The Present" focuses on ITER, looking at the political and organisational challenges it faces as well as the engineering ones. And "The Future" looks at the challenges of designing an actual fusion power plant.
Three chapters cover extra topics. Alternative approaches to fusion, some of them being worked on by commercial startups, include stellarators (with complex magnetic field geometries making the physics easier at the expense of extra engineering challenges), inertial confinement (using lasers to implode small fuel capsules), spherical tokamaks, cusp geometries, different fuels, and high-temperature superconductors. Nuclear fission raises obvious weapons proliferation risks; fusion would not remove these entirely but would, Parisi and Ball argue, drastically reduce them. And: "While fusion clearly has a very long way to go before it will be powering an interstellar colonization mission, it is the only technology that appears capable of such a feat".
Their answer in the concluding "When Will We Have Fusion?" is that it largely depends on how much we are prepared to pay — fusion research funding is tiny, compared either to research into other energy sources or historical predictions of how much would be needed. Parisi and Ball argue that "the multitude of disciplines involved and their interconnectedness is the greatest reason for optimism", picking up a statement in the introduction that "our current ignorance and the complexity of fusion are reasons for confidence in fusion". Which actually inverts my previous feel for the situation: it seems we have progressed far enough now that we need improvements in a few areas, not almost everywhere. In any event, Parisi and Ball make a convincing case that commercial fusion energy is likely to happen and, given its potential importance, worth investing far more in than we currently are.
It is unlikely to confuse purchasers, but the pastries on the cover of The Future of Fusion Energy are slightly disconcerting and I'd be surprised if at least one bookshop doesn't manage to misfile it under "cooking". The illustrations are decent: halftones, some in colour, give a feel for the appearance of key pieces of equipment, and the diagrams and charts support the text. And this is a nicely put together hardcover with quality paper and a good heft to it. The downside is that The Future of Fusion Energy is priced, with the paperback at forty pounds, rather too much like an academic monograph.
It may be too dense to appeal to a mass audience, but for a good many people The Future of Fusion Energy will be the perfect guide to one of humanity's great scientific and engineering endeavours. It fills a gap between more popular books, with more on the people and politics, and more technical works, aimed at students or researchers.