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Playing the “bad guy” to enhance next-generation safety
Sometimes, cops and robbers is more than just a kid’s game. At the Department of Energy’s national laboratories, researchers are channeling their inner saboteurs to discover vulnerabilities in next-generation nuclear reactors, making sure that they’re as safe as possible before they’re even constructed.
Kiyomasa Y. Watanabe, Arthur Weller, Satoru Sakakibara, Yoshiro Narushima, Satoshi Ohdachi, Kazumichi Narihara, Kenji Tanaka, Katsumi Ida, Kazuo Toi, Hiroshi Yamada, Yasuhiro Suzuki, Osamu Kaneko, Large Helical Device Experimental Group, Wendelstein 7-AS Experimental Group
Fusion Science and Technology | Volume 46 | Number 1 | July 2004 | Pages 24-33
Technical Paper | Stellarators | doi.org/10.13182/FST04-A537
Articles are hosted by Taylor and Francis Online.
Recently, dramatic progress has been achieved in the study of helical systems with high-beta experiments. Discharges with more than 3% beta plasmas have been achieved in Large Helical Device (LHD) and Wendelstein 7-AS (W7-AS). Although magnetohydrodynamic (MHD) instabilities affect local pressure gradients, the global transport property does not seem to limit the achieved beta value in either device. We summarize the LHD high-beta properties in MHD stability, equilibrium, and transport, and we show the relationship between the experimentally achieved parameters and theoretical predictions. We contrast the LHD results with the W7-AS high-beta properties. In both devices, stationary discharges in the definitely MHD unstable region have not been observed. We mention the key issue for achievement of the beta values >5%.