The impact of toroidal mode coupling on high-density discharges in J-TEXT
Density limit has long been a widely studied issue influencing the operating range of tokamaks. The rapid growth of the m / n = 2/1 (where m and n are poloidal and toroidal mode numbers, respectively) tearing mode is generally regarded as a primary precursor to the density limit disruption. In this...
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Veröffentlicht in: | Plasma science & technology 2024-12, Vol.26 (12), p.125101 |
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Hauptverfasser: | , , , , , , , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Density limit has long been a widely studied issue influencing the operating range of tokamaks. The rapid growth of the m / n = 2/1 (where m and n are poloidal and toroidal mode numbers, respectively) tearing mode is generally regarded as a primary precursor to the density limit disruption. In this experiment, the coupling of the m / n = 1/1 mode and the m / n = 2/1 mode in high-density plasma was observed. During a sawtooth cycle, the frequencies of the two modes gradually converge until they become equal. After that, toroidal coupling occurs between the 1/1 and 2/1 modes, resulting in a mutually fixed phase relationship. With the occurrence of toroidal coupling, the 2/1 mode is stabilized. Prior to the disruption, the cessation of the 1/1 and 2/1 mode coupling, along with the rapid growth in the amplitude of the 2/1 mode, can be observed. Additionally, under the same parameters, comparing discharges with or without the 1/1 mode, it is found that the presence of the 1/1 mode leads to higher plasma density and temperature parameters. |
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ISSN: | 1009-0630 |
DOI: | 10.1088/2058-6272/ad659f |