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Fusion energy: Progress, partnerships, and the path to deployment
Over the past decade, fusion energy has moved decisively from scientific aspiration toward a credible pathway to a new energy technology. Thanks to long-term federal support, we have significantly advanced our fundamental understanding of plasma physics—the behavior of the superheated gases at the heart of fusion devices. This knowledge will enable the creation and control of fusion fuel under conditions required for future power plants. Our progress is exemplified by breakthroughs at the National Ignition Facility and the Joint European Torus.
Kozo Yamazaki, Osamu Motojima, Makoto Asao
Fusion Science and Technology | Volume 21 | Number 2 | March 1992 | Pages 147-160
Technical Paper | Experimental Device | doi.org/10.13182/FST92-A29734
Articles are hosted by Taylor and Francis Online.
Optimization studies have been carried out for the proposed Large Helical Device, which has a major radius of ∼4 m and a magnetic field of ∼4 T, in which a key experiment is to demonstrate a divertor concept. These studies clarified that configurations with a higher helical coil pitch parameter γc (γc ≳ 1.25) and a larger plasma minor radius are not consistent with the requirement of a clean divertor configuration. More compact, lower m systems (m ≲ 8) without helical coil pitch modulation are ruled out by the equilibrium beta limit of the plasma and the stability limit of the superconducting coil current because of the higher maximum magnetic field strength. Systems with a larger aspect ratio and larger m (m ≳ 12, γc ∼ 1.2 to 1.3) with better neoclassical confinement properties are not effective because of a lower stability beta and a narrower clearance between the divertor layer and the wall. An l = 2/m = 10/γc = 1.2 superconducting system is found to be an optimized high-nτT configuration for 4 m/4 T next-generation experiments with respect to the high-beta requirement, clean divertor installation, superconducting coil engineering, and cost optimization.