Fig. 7.

Horizontal component temporal behaviour, as seen by one-minute values, around the storm of 28–29 October (left), and 20–21November, 2003 (right) at CLF and HER, and the associated wavelet spectral exponents. The SYM-H index is also plotted. The vertical dashed lines delineate the storm onset. Labels T1 to T6 above the scaling exponent indicate the phase transition near the storm onset. Minor ticks on the abscissa equal two-hour intervals. The horizontal dashed lines indicate the transition from an antipersistent (1 < β < 2) to persistent (2 < β < 3) behaviour of the field.