Studies of mode lock instability in the HL-1M tokamak
Locked mode instability in the HL-1M tokamak has been investigated in this paper. In the HL-1M tokamak the mode lock instability often appears in with low density discharges (<img src="http:/img/fbpe/bjp/v32n1/27eq01.gif" align="absMiddle"> < 1 × 10(19) m-3). The precursor perturbations on both soft-X rays and Mirnov signals simultaneously increase before mode locking. Their frequencies are the same and gradually decease, which indicate that the perturbation is global. Their existence time-scale is about 10ms. The plasma will suddenly stop rotating when the fluctuation amplitude or frequency reaches a threshold. Mode lock instability can often cause major disruptions. The rotation frequency is decreased to about 3kHz before mode locking in the HL-1M tokamak, which is consistent with the theoretical model.
| Main Authors: | , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Sociedade Brasileira de Física
2002
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332002000100027 |
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| Summary: | Locked mode instability in the HL-1M tokamak has been investigated in this paper. In the HL-1M tokamak the mode lock instability often appears in with low density discharges (<img src="http:/img/fbpe/bjp/v32n1/27eq01.gif" align="absMiddle"> < 1 × 10(19) m-3). The precursor perturbations on both soft-X rays and Mirnov signals simultaneously increase before mode locking. Their frequencies are the same and gradually decease, which indicate that the perturbation is global. Their existence time-scale is about 10ms. The plasma will suddenly stop rotating when the fluctuation amplitude or frequency reaches a threshold. Mode lock instability can often cause major disruptions. The rotation frequency is decreased to about 3kHz before mode locking in the HL-1M tokamak, which is consistent with the theoretical model. |
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