Pursuing Solar Power: A Hundred Years of Fusion Energy Developments, from Aston to Tokamak
In the 1920s and 1930s, the world witnessed significant advancements in atomic theory and particle physics. Arthur Eddington proposed that the sun's energy might derive from the fusion of hydrogen into helium, linking nuclear physics with stellar thermodynamics [3]. Around the same time, research on cosmic rays and nuclear particles helped advance knowledge about high-energy particles and nuclear processes, setting the stage for controlled nuclear fusion research [4].
However, the focus shifted during the 1939-1945 period towards nuclear fission research and the development of the atomic bomb, culminating in the Manhattan Project [1]. The hydrogen bomb, or thermonuclear weapon, demonstrated fusion reactions could be initiated in Earth-bound conditions in 1952, but its use was unsuitable for civilian purposes [2].
From the 1950s onward, scientific efforts shifted to achieving controlled fusion for energy production. The Soviet Union made a pivotal contribution to this endeavour with the development of the tokamak, a doughnut-shaped device that used magnetic fields to confine plasma [5]. This marked the beginning of magnetic confinement fusion research, which would later become the dominant paradigm for fusion research by the 1970s, supplanting rival designs such as stellarators and magnetic mirrors [6].
The Lawrence Livermore National Laboratory in California played a significant role in the development of inertial confinement fusion (ICF). Facilities like Shiva and the National Ignition Facility were built at the laboratory for ICF research [7]. Inertial confinement, the use of lasers to compress and heat a small pellet of fusion fuel, is another approach to achieving sustained fusion reactions [8].
ITER (International Thermonuclear Experimental Reactor) is the most ambitious fusion project to date, funded by a consortium including the EU, U.S., China, Russia, Japan, South Korea, and India [9]. ITER seeks to demonstrate sustained fusion at energy gain, but its timeline has extended by decades, costs have ballooned, and its geopolitical consensus remains fragile [10].
Each new fusion reactor, such as JET in the UK, TFTR at Princeton, JT-60 in Japan, pushed the boundary further, but none could achieve "breakeven," the point at which a fusion reaction produces as much energy as it consumes [11]. Fusion's immense potential made it politically irresistible, but its complexity and long-term nature made it vulnerable to funding cuts [12].
The development of plasma physics, the study of ionized gases under high temperature, was essential to understanding the conditions necessary for sustained fusion [13]. The pursuit of fusion has transformed various scientific fields, including plasma physics and materials engineering, and has trained generations of researchers [14].
The long arc of fusion may yet culminate in power plants that produce no carbon, no waste, and no warheads, but that day remains distant [15]. Fusion energy is a reminder of the scale of ambition necessary to reimagine civilization's energy foundations. Despite the challenges, the history of fusion energy research from 1920 to the present is marked by overpromises and the difficulty of translating scientific milestones into technological revolutions [16].
- In the shift of focus from the 1940s, the application of fusion reactions moved from potential weapons to potential energy sources, leading to the goal of controlled fusion for environmental-science benefits in the 1950s.
- The development of magnetic confinement fusion research in the 1950s, led by the Soviet Union's tokamak, and later inertial confinement fusion by the Lawrence Livermore National Laboratory, represent advancements in technology and energy.
- The ambitious ITER project, a collaboration among multiple nations, aims to demonstrate sustained fusion at energy gain, illustrating the intersection of science, finance, climate-change, and industry, with the ultimate goal of producing clean and sustainable energy.
