Authors: Xi Lu (UTD), Ivan Vasko (UTD), Zubair Shaikh (UTD), Forrest Mozer (UCB)

Interplanetary shocks are ubiquitous in the heliosphere and are always associated with electrostatic fluctuations. We identified 18 fast forward interplanetary shocks and 18,542 planar waves at 1 AU using burst mode measurements from the Magnetospheric Multiscale satellite mission between September 2015 and January 2026. Statistical analysis shows that the planar wave packets have plasma-frame phase speeds comparable with the local ion-acoustic speed, wavelengths of several tens of Debye lengths, and electrostatic potential amplitudes smaller than 0.5% of the local electron temperature. In addition, the waves generally propagate aligned with local magnetic field but are more oblique at quasi-perpendicular shocks. The correction procedure applied to the attenuated electric fields performs well for the high-frequency signals, with ~40% of the waves corrected by more than 20% relative to the original measurements. The occurrence rate of waves is not found to be associated with the shock geometry or relative location (upstream, ramp or downstream) to the shock structure.