Friday 21 March 2025
The XuanLong-50 (EXL-50) experiment, conducted at the Hebei Key Laboratory of Compact Fusion in China, has made significant strides in advancing our understanding of plasma confinement and current drive in spherical torus devices. The researchers have successfully demonstrated non-inductive current start-up using electron cyclotron waves (ECRH), achieving plasma currents of up to 180 kiloamperes.
One of the key challenges in achieving stable plasmas is maintaining a high level of energetic electrons outside the last closed flux surface (LCFS). The EXL-50 team has achieved this by employing multiple techniques, including ECRH and lower hybrid current drive (LHCD). These methods have allowed them to create a stable plasma with a high level of energetic electrons, which is essential for maintaining a strong magnetic field.
The researchers have also investigated the effects of boron injection on plasma confinement. Boron has been shown to be an effective tool in suppressing plasma-wall interaction and edge turbulence, leading to improved plasma stability. The team has observed a significant increase in plasma density after boron injection, indicating that this technique can be used to improve plasma performance.
Another notable achievement is the development of a new type of magnetic coil, which allows for more precise control over the plasma shape and position. This coil, known as the poloidal coil (PF), has enabled the researchers to achieve a high level of plasma confinement and stability.
The EXL-50 experiment has also shed light on the role of energetic electrons in plasma confinement. The team has found that these electrons play a crucial role in maintaining the magnetic field and preventing plasma losses. This understanding is critical for developing more efficient and stable plasmas in future fusion devices.
The results of the EXL-50 experiment have significant implications for the development of compact fusion reactors. By achieving non-inductive current start-up using ECRH, the researchers have demonstrated a viable approach to creating high-performance plasmas without the need for large-scale magnetic coils. This technology has the potential to enable more compact and efficient fusion devices, making it an important step towards realizing practical fusion power.
Overall, the XuanLong-50 experiment has made significant progress in advancing our understanding of plasma confinement and current drive in spherical torus devices. The results have important implications for the development of compact fusion reactors and highlight the potential of ECRH as a viable approach to achieving high-performance plasmas.
Cite this article: “Advances in Plasma Confinement and Current Drive in Spherical Torus Devices”, The Science Archive, 2025.
Fusion, Plasma Confinement, Current Drive, Spherical Torus, Electron Cyclotron Waves, Lower Hybrid Current Drive, Boron Injection, Magnetic Field, Compact Fusion Reactors, Exl-50 Experiment
