Partial and major disruptions in the JIPP T-II tokamak

High-density disruptions and low-q disruptions have been investigated by soft-X-ray imaging on the JIPP T-II tokamak. Although an m = 3 / n = 2 mode is identified together with a 2/1 mode before partialdisruptions in high-density discharges, the resulting disturbance is limited and the central region is not affected. The growth of the 3/2 mode detected in low-q discharges leads to a rearrangement of the soft-X-ray profile by a 1/1 mode. The essential feature of major disruptions is the abrupt central thermal quench. Before major disruptions the predominant 2/1 mode is modulated by a central 1/1 component. The 1/1 mode is found to play an important role in the final stage of major disruptions, both in high-density discharges and in low-q discharges.

[1]  T. Tsunematsu,et al.  Numerical studies of toroidal coupling on low-m resistive modes , 1983 .

[2]  D. Robinson,et al.  Major Disruptions in the TOSCA Tokamak , 1980 .

[3]  D. Edery,et al.  Current‐driven internal kink modes in cylindrical and helicoidal discharges , 1976 .

[4]  B. V. Waddell,et al.  Nonlinear interaction of tearing modes in highly resistive tokamaks , 1979 .

[5]  A. Cormack.  Representation of a Function by Its Line Integrals, with Some Radiological Applications , 1963 .

[6]  K. Sakurai,et al.  Current density profile control by programming of gas puffing and plasma current waveform in the JIPP T-II tokamak , 1979 .

[7]  C. Reverdin,et al.  Internal disruptions in the TFR tokamak: A phenomenological analysis , 1983 .

[8]  H. R. Hicks,et al.  Effects of toroidal coupling on the stability of tearing modes , 1981 .

[9]  J. Wesson,et al.  Major disruptions in tokamaks , 1980 .

[10]  A. Pochelon,et al.  Method of cartography of q = 1 islands during sawtooth activity in tokamaks , 1980 .

[11]  B. Kadomtsev.  Behaviour of disruptions in Tokamaks , 1984 .

[12]  K. Kawahata,et al.  Soft X-ray tomography in the JIPP T-II stellarator , 1982 .

[13]  N. R. Sauthoff,et al.  A study of disruptive instabilities in the PLT tokamak using X-ray techniques , 1978 .

[14]  Takeaki Enoto,et al.  A New Numerical Method for Asymmetrical Abel Inversion , 1981, IEEE Transactions on Plasma Science.

[15]  K. Lackner,et al.  Current Disruption in Toroidal devices , 1979 .

[16]  J. Wesson,et al.  Transport, instability and disruptions in tokamaks , 1982 .

[17]  R. Petrasso,et al.  Effects of internal disruptions on impurity transport in tokamaks , 1983 .

[18]  Soft X-Ray Tomography of the m =2 Magnetic Island Structure in the JIPP T-II Tokamak , 1981 .

[19]  Equipe Tfr.  Structure of low-frequency oscillations during the disruptive instability in the TFR tokamak , 1977 .

[20]  B. V. Waddell,et al.  Mechanism for Major Disruptions in Tokamaks , 1978 .

[21]  B. V. Waddell,et al.  Nonlinear coupling of tearing modes with self‐consistent resistivity evolution in tokamaks , 1980 .