\n
![\"EarthSnap\"\/](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/01\/1767702488_540_earthsnap-banner-news.webp.webp\")
\n<\/a><\/p>\n
Fusion energy<\/a> comes from joining light atoms together, just like inside the Sun. Scientists hope fusion can one day provide clean and endless power. <\/p>\n Achieving that goal requires plasma that stays hot, dense, and stable for long periods.<\/p>\n Density has always caused trouble. Once density rises too much, plasma usually collapses. New experiments on China\u2019s EAST reactor show that problem no longer looks permanent.<\/p>\n The research was led by Jiaxing Liu and Professor Ping Zhu from Huazhong University of Science and Technology<\/a> and the University of Wisconsin Madison<\/a>.<\/p>\n China\u2019s artificial sun reactor<\/p>\n The Experimental Advanced Superconducting Tokamak, known as EAST, sits at the Institute of Plasma Physics under the Chinese Academy of Sciences in Hefei. <\/p>\n EAST uses strong magnetic fields to hold plasma in place while heating it to extreme temperatures. <\/p>\n Full metal walls made of tungsten surround the plasma, unlike older machines that used carbon<\/a>.<\/p>\n Why high density matters<\/p>\n Fusion reactions grow stronger as plasma density rises. When density doubles, fusion power rises much faster. High density helps fusion reach ignition, the point where reactions power themselves. <\/p>\n Despite that benefit, tokamaks face a density ceiling called the Greenwald limit. Crossing that line often triggers plasma collapse.<\/p>\n Older explanations blamed turbulence or magnetic problems. Many experiments tried adding more fuel or heating, but disruption usually followed. A new idea now offers a deeper explanation.<\/p>\n Plasma wall self-organization, or PWSO, explains density limits by focusing on interactions between plasma and reactor walls. <\/p>\n D. F. Escande and collaborators first developed the idea. PWSO links plasma behavior to impurity radiation caused by wall materials.<\/p>\n When plasma hits metal walls, tiny particles break loose. Those particles enter plasma and radiate energy away. Too much radiation cools the plasma<\/a> and ends the experiment. <\/p>\n PWSO theory shows that balance between heating power and radiation decides how dense plasma can become.<\/p>\n Two operating paths appear in PWSO theory. One path leads to a density limit. Another path leads to a density-free regime. In that second path, plasma stays stable even as density keeps rising.<\/p>\n Why tungsten walls matter<\/p>\n Wall material plays a major role. Carbon walls release impurities through chemical reactions. Tungsten walls release particles mainly through physical impacts. <\/p>\n Physical sputtering behaves in a more predictable way at lower temperatures.<\/p>\n PWSO theory predicts that tungsten walls can support the density-free regime when target region temperatures remain low. <\/p>\n EAST uses full tungsten divertors, which creates ideal conditions for testing that idea.<\/p>\n Stabilizing the artificial sun<\/p>\n Researchers adjusted conditions at the very start of plasma formation. High initial gas pressure filled the chamber before plasma ignition. Electron cyclotron resonance heating supplied extra energy during startup.<\/p>\n That combination reduced harmful radiation and kept plasma clean. Lower impurity levels allowed density to rise smoothly. Plasma temperature near divertor targets dropped, which further reduced wall damage and radiation.<\/p>\n Measurements showed plasma density reaching about 1.3 to 1.65 times the Greenwald limit. Stability remained strong even near collapse. <\/p>\n The results matched predictions from both simplified and detailed PWSO models.<\/p>\n Theory supports the findings<\/p>\n PWSO models describe feedback between heating power, radiation, and impurity production. When delayed radiation stays below heating input, plasma reaches a stable balance. <\/p>\n Calculations showed that EAST experiments entered the density-free basin predicted by theory. Lower divertor temperatures played a key role.<\/p>\n As wall conditions improved over repeated experiments, density limits increased even more. That trend matched theoretical expectations closely.<\/p>\n Why these results matter<\/p>\n Fusion ignition depends on density, temperature, and confinement time working together. Removing the density barrier brings ignition much closer. <\/p>\n EAST results show that startup control and wall design matter as much as raw heating power.<\/p>\n \u201cThe findings suggest a practical and scalable pathway for extending density limits in tokamaks and next generation burning plasma fusion devices,\u201d said Professor Zhu.<\/p>\n Professor Ning Yan noted that the team plans to apply the same method during high confinement operation. That step could push density even higher under stronger fusion conditions.<\/p>\n Fusion energy<\/a> still faces challenges, but one of the hardest limits has begun to fall. With careful control and smart design, artificial suns may soon burn brighter than ever before.<\/p>\n The study is published in the journal Science Advances<\/a>. <\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.\u00a0<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"China has moved one step closer to clean fusion energy by breaking a long-standing rule in plasma physics.…\n","protected":false},"author":2,"featured_media":391333,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[49],"tags":[199,79],"class_list":{"0":"post-391332","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-physics","9":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/391332","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=391332"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/391332\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/391333"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=391332"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=391332"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=391332"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}