Figure 2.
An illustrative example of an interplanetary shock exhibiting both a dispersive (purple arrows) and nearly constant frequency (magenta arrows and boxes) whistler precursors observed by the Wind spacecraft, (first and second panels) The same format as Figure 1. Shown are the Morlet wavelet transforms [Torrence and Compo, 1998], from top-to-bottom, of (third panel) |Bo|, (fourth panel) Box, (fifth panel) Boy, and (sixth panel) Boz, with wavelet power range shown to the right as color bars. Figure 2 (first panel) shows the same upstream shock parameters as in Figure 1. Finally, the green vertical line denotes the separation between upstream (to left) and downstream (to right) regions.