Figure 1a. Time variations
of solar wind and IMF parameters,
beginning from 4 days prior to
the key day (day 0), which
corresponds to the commencement of a sequence of four consecutive quiet
days with
Ap 4, and up to 4 days after the termination
of the sequence of quiet intervals. The label
sig. before
the variable indicates the hourly variability in the parameter, as
reported in the OMNI tape for the period 1963 to July 1998.
The units are km s-1 for solar wind
velocity and its variability,
n cm3 for density, and nT for all other parameters
(B, its components, and their variability).