ULF waves downstream of ICME driven shocks.

IP shocks can be driven in the solar wind by fast coronal mass ejections. Past studies have shown that a variety of ULF waves can be observed upstream of these shocks. Less attention has been given to understand what wave modes permeate the sheath regions downstream of these shocks. It is expected that due to temperature anisotropy, ion cyclotron and mirror mode waves can grow downstream of IP shocks in a similar way to planetary magnetosheaths. Understanding these waves is important because they contribute to shock acceleration processes. In this work we use STEREO data to study wave structure downstream of ICME driven shocks. The waves observed downstream of IP quasi-parallel shocks have larger amplitudes than waves in the regions downstream of quasi-perpendicular shocks.  A variey of waves can be found in the sheath regions of ICMEs, even when IP shocks are weak, mostly for quasi-perpendicular shocks. These include ion cyclotron waves (ICW) with well defined peaks in frequency, broad spectra ICW and mirror mode storms, which tend to occur for higher plasma beta.