THE STRUCTURE OF MAGNETIC FLUCTUATIONS IN HBTX-1A REVERSED FIELD PINCH
Arrays of edge magnetic coils and statistical analysis techniques have been used to investigate the magnetic fluctuation structure in HBTXIA Reversed Field Pinch. The superficially random fluctuations can in fact be attributed almost entirely to global modes with poloidal mode number m = 0 and 1 provided account is taken of toroidal distortion of the modes. A toroidal array of coils discloses a broad spectrum of toroidal mode numbers with peak at *n* +- 10 and significant variation with time and frequency. Cross correlation establishes that the *n* +- 10 is m = 1, a helical mode resonant inside the reversal surface and also shows the presence of m = 0, n +- 0. The time scales of the fluctuation indicate that the instabilities are probably resistive in character and mode amplitudes are such that island overlap and magnetic field ergodization should occur. The energy confinement time due to stochastic transport, estimated from the measured fluctuations, is consistent with that experimentally observed.
Bibliographic Reference: WRITE TO THE LIBRARY, UKAEA, CULHAM LABORATORY, ABINGDON, OXON. OX14 3DB (UK), MENTIONING REPORT CLM-P 701, 1983
Record Number: 1989122050500 / Last updated on: 1987-01-01
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