Chinese Scientists Achieve Record Breakthrough in Sustained ELM-Free Plasma Operation Within Metal-Wall Tokamak Environment

Chinese researchers demonstrate a DTP plasma regime on the EAST tokamak, achieving sustained ELM-free high confinement and divertor detachment.

By: AXL Media

Published: Apr 30, 2026, 6:28 AM EDT

Source: Information for this report was sourced from EurekAlert!

Engineering a Sustainable Path for Long-Pulse Nuclear Fusion

Managing the extreme thermal conditions of a nuclear fusion reactor requires a delicate balance between cooling the exhaust components and maintaining the high-temperature core. A research team from the Hefei Institutes of Physical Science, Chinese Academy of Sciences, has achieved a significant milestone by demonstrating a plasma regime that integrates three critical requirements for stable operation. Led by Professor Xu Guosheng, the team successfully sustained a state that combines partial divertor detachment, high pedestal performance, and the total suppression of damaging energy bursts within the EAST tokamak.

The Mechanics of the Detached Divertor and Turbulence-dominated Pedestal

The researchers have termed this breakthrough the Detached divertor and Turbulence-dominated Pedestal (DTP) regime. This state was achieved by carefully controlling the injection of light impurity gases into the reactor chamber in real time. By fine-tuning this gas seeding, the team managed to create a cooling effect at the divertor plates, significantly reducing the heat flux that typically threatens to damage reactor components. Unlike previous experiments where excessive cooling might degrade the plasma edge, the DTP regime maintains a stable and high-performance environment suitable for long-term power generation.

Solving the Volatility of Edge-Localized Modes

One of the primary obstacles to controllable fusion is the occurrence of edge-localized modes (ELMs), which are sudden bursts of heat and particles that can erode the metal walls of a tokamak. In the DTP regime, these ELMs are completely suppressed, allowing for a steady-state high-confinement mode. According to the research findings, the system utilizes a closed divertor geometry to trap and pump neutral particles. This configuration prevents the cooling of the plasma pedestal and instead enhances the temperature gradient, which is essential for efficient energy confinement and reactor stability.