  We present a statistical analysis of 132 dayside (LT 0700-1700) bow shock
crossings of the AMPTE/IRM spacecraft. We perform a superposed epoch analysis
of plasma and magnetic field parameters as well as of low frequency magnetic
power spectra some minutes upstream and downstream of the bow shock by dividing
the events into categories depending on the angle between bow shock normal and
interplanetary magnetic field and on the plasma-beta, i.e., the ratio of plasma
to magnetic pressure.
  Downstream of the quasi-perpendicular low-beta (beta < 0.5) bow shock we find
a dominance of the left-hand polarized component at frequencies just below the
ion cyclotron frequency with amplitudes of about 3 nT. These waves are
identified as ion cyclotron waves which grow in a low-beta regime due to the
proton temperature anisotropy. We find a strong correlation of this anisotropy
with the intensity of the left-hand polarized component. Downstream of some
nearly perpendicular high-beta (beta > 1.0) crossings mirror waves are
identified. However, there are also cases where the conditions for mirror modes
are met downstream of the nearly perpendicular shock, but no mirror waves are
observed.
