Transport and Stability Studies in Negative Central Shear Advanced Tokamak Plasmas
| Autor: | Raghavan Jay Jayakumar |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Physics
Nuclear and High Energy Physics Tokamak 020209 energy Mechanical Engineering Magnetic confinement fusion 02 engineering and technology Kink instability 01 natural sciences 010305 fluids & plasmas law.invention Bootstrap current Computational physics Nuclear Energy and Engineering law Beta (plasma physics) 0103 physical sciences 0202 electrical engineering electronic engineering information engineering Electron temperature General Materials Science Atomic physics Shear flow Stellarator Civil and Structural Engineering |
| Zdroj: | Fusion Science and Technology. 46:225-233 |
| ISSN: | 1943-7641 1536-1055 |
| DOI: | 10.13182/fst04-a559 |
| Popis: | 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 formationmore » 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 x B flow shear rate and rarefaction of resonant surfaces near the rational q{sub min} 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.« less |
| Databáze: | OpenAIRE |
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