Fig. 6: Mirror to FRC transition induced by an increase in total NBI power, the axial bounce frequency of the fast ions is observed to increase during the reversal process as the turning points (TP) move toward the mid-plane.
From: Generation of field-reversed configurations via neutral beam injection
a Temporal evolution of excluded flux radius, rΔϕ, (left abscissa) and neutral-beam injection power (right abscissa); mirror and FRC plasma regimes are highlighted by orange and blue, respectively, with a transition zone between them. b Spectrogram of Bz fluctuations with n = 0 azimuthal structure and averaged over measurements at axial locations z = ± 0.48 m, the ABM and harmonics are indicated by arrows and the vacuum bounce frequency of fast ions sourced from NBI by the dashed white line. c Axial structure of the axial bounce mode in the Mirror and FRC regions (left abscissa) and vacuum field magnitude (right abscissa); the turning point regions identified by the peak amplitude of the mode (shaded regions) and the turning points of the vacuum field (black dashed lines) are indicated. Error bars represent the standard deviation of the mode amplitude over time.
