A team of engineers at the UK Atomic Energy Authority has reached a significant milestone in fusion energy research by successfully stabilizing plasma using a three-dimensional magnetic field. This groundbreaking experiment marks the first time such plasma stabilization has been achieved in a spherical tokamak, potentially overcoming a major challenge in the quest for abundant fusion energy.
Nuclear fusion, the process that powers the sun, involves combining two lighter atomic nuclei to form a heavier nucleus, releasing vast amounts of energy. A tokamak employs powerful magnets to control and stabilize the plasma necessary for these reactions. The largest operational spherical tokamak, known as MAST Upgrade, was commissioned by the UKAEA in collaboration with the European Atomic Energy Community and has been operational since 2020 at the Culham Centre for Fusion Energy in Oxfordshire.
In order to achieve fusion within the MAST Upgrade, researchers must confine fusion fuel at extremely high temperatures, which allows the fuel to transition into plasma. However, maintaining plasma stability is crucial, as excessive pressure, density, or current can lead to instability and poor performance, potentially damaging the tokamak”s components.
According to a press statement from the UK government, the UKAEA team utilized Resonant Magnetic Perturbation (RMP) coils to effectively suppress Edge Localized Modes (ELMs) within the MAST Upgrade. ELMs are instabilities that arise at the plasma”s edge and can create serious complications for fusion plant components. The application of a small 3D magnetic field at the plasma edge represents a historic first in the context of spherical tokamaks.
“Suppressing ELMs in a spherical tokamak is a landmark achievement,” stated James Harrison, Head of MAST Upgrade Science at UKAEA. “It is an important demonstration that advanced control techniques developed for conventional tokamaks can be successfully adapted to compact configurations, laying the groundwork for future power plants like STEP, the Spherical Tokamak for Energy Production.”
This experiment was part of MAST Upgrade”s fourth scientific campaign, which primarily focused on understanding plasma characteristics and managing plasma exhaust. The findings from this research are expected to significantly advance the development of ELM control systems for the UK”s STEP program, which aims to generate net electricity from fusion energy by 2040. The STEP initiative is central to a £2.5 billion investment by the UK government, aimed at making nuclear fusion a viable energy source.
