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60 Years of U: Perspectives on resources, demand, and the evolving role of nuclear energy
Recent years have seen growing global interest in nuclear energy and rising confidence in the sector. For the first time since the early 2000s, there is renewed optimism about the industry’s future. This change is driven by several major factors: geopolitical developments that highlight the need for secure energy supplies, a stronger focus on resilient energy systems, national commitments to decarbonization, and rising demand for clean and reliable electricity.
Raghavan Jay Jayakumar
Fusion Science and Technology | Volume 46 | Number 2 | September 2004 | Pages 225-233
Technical Papers | Stellarators | doi.org/10.13182/FST04-A559
Articles are hosted by Taylor and Francis Online.
Achieving high performance for long duration is a key goal of advanced tokamak research around the world. To this end, tokamak experiments are focusing on obtaining (a) a high fraction of well-aligned noninductive plasma current, (b) internal transport barriers (ITBs) in the ion and electron transport channels over a wide radial region with transport approaching neoclassical values, and (c) control of resistive wall modes and neoclassical tearing modes that limit the achievable beta. A current profile that yields a negative central magnetic shear (NCS) in the core is consistent with this focus; NCS is conducive for obtaining ITBs, a high degree of bootstrap current alignment, and reaching the second stability region for ideal ballooning modes, while being stable to ideal kink modes at high beta with wall stabilization and neoclassical tearing modes in the core NCS region. Much progress has been made in obtaining advanced performance in several tokamaks through an increasing understanding of the stability and transport properties of tokamak plasmas. Radio-frequency and neutral beam current drive scenarios are routinely developed and implemented in experiments to access new advanced regimes and control plasma profiles. Short-duration and sustained ITBs have been obtained in the ion and electron channels. The formation of an ITB is attributable to the stabilization of ion and electron temperature gradient and trapped electron modes by the negative shear and by the enhanced E × B flow shear rate and rarefaction of resonant surfaces near the rational qmin values. The progress in understanding the underlying physics in such plasmas and the development of techniques and technology would be of interest in stellarator efforts.