Fusion energy promises to be a sustainable, safe, and low-carbon method of electricity production that could play a key role in reducing global emissions of greenhouse gases. In the core of a fusion device, at temperatures so high that all gases ionise to form plasmas, light isotopes fuse together to form heavier elements, releasing energy in the process. This energy can then be converted into electricity. There are several different types of fusion devices being actively researched and built worldwide by both public and private organisations, all with the hope of proving commercial-viability of electricity production.
Of all the concepts, the tokamak, a doughnut-shaped machine that confines plasma using magnetic fields, has been proven to have the best fusion performance. The Columbia team studied a variation of the design of the traditional tokamak, known as the negative-triangularity tokamak, over the summer.
In a tokamak, a series of electromagnetic coils produce magnetic fields that spiral around the inside of a doughnut-shaped vacuum vessel, and the plasmas confined typically have a ‘positive-triangularity’ shape, when viewed from a cross-section of the tokamak, see Figure 2, right-side. A different configuration of coils can change this cross-section to form a ‘negative-triangularity’ shape, see Figure 2, left. This new shape holds several advantages for confining the hot plasma compared to the traditional shape, and is the subject of an increasing amount of research and experimentation.