PSD of magnetic field fluctuations upstream and downstream of the bow shock shown in Figure 1. The PSDs are calculated using 1 hr intervals in the upstream and downstream regions. The dashed lines mark the proton gyrofrequencies for the upstream (﹩{f}_{cp}^{u}﹩) and downstream (﹩{f}_{cp}^{d}﹩) regions. The dashed–dotted lines mark the Taylor-shifted frequencies associated with the proton inertial length for the upstream (﹩{f}_{dp}^{u}﹩) and downstream (﹩{f}_{dp}^{d}﹩) regions.