中国“人造太阳”实验找到突破密度极限方法

Core Viewpoint - The research team from the Hefei Institute of Physical Science, Chinese Academy of Sciences, has confirmed the existence of a density free zone in the EAST (Experimental Advanced Superconducting Tokamak) nuclear fusion device, providing significant physical evidence for high-density operation in magnetic confinement fusion devices [1] Group 1: Research Findings - The EAST device utilizes magnetic confinement to achieve controlled nuclear fusion, functioning as a spiral "magnetic track" that traps high-temperature plasma [1] - Plasma density is a critical parameter affecting fusion reaction rates, and the research developed a theory model (PWSO) to understand the interaction between boundary plasma and wall [1] - The study revealed that radiation instability caused by boundary impurities plays a key role in triggering the density limit, elucidating the mechanism behind this limit [1] Group 2: Experimental Methods - Researchers employed methods such as electron cyclotron resonance heating and pre-filling gas to reduce boundary impurity sputtering, actively delaying the onset of the density limit and plasma disruption [1] - By adjusting the physical conditions of the target plate, the team reduced tungsten impurity-induced sputtering, allowing plasma to surpass the density limit and enter a new density free zone [1] - The experimental results were in high agreement with the predictions made by the PWSO theory, marking the first confirmation of the existence of a tokamak density free zone [1]