Authors: Neha Pathak(Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, 80303, USA),R. E. Ergun (Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, 80303, USA),T. Vo(T. Vo),Y. Qi(Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, 80303, USA), A. Chasapis(Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, 80303, USA), N. Ahmadi(Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, 80303, USA)

The presence of nonlinear structures like double layers (DLs), electron phase space holes, and other electrostatic structures are often observed in the plasma sheet boundary layer of the Earth’s magnetotail. The Magnetospheric Multiscale (MMS) mission has provided valuable multi-point observations, suggesting that Nonlinear Ion-Acoustic Waves (NIAWs) are prevalent in this region and appear to play a substantial role in mixing of the two plasma populations from the plasma sheet and the lobes, particularly during active periods when the magnetosphere is influenced by external disturbances. MMS observations have shown that these NIAWs have parallel electric fields with amplitudes up to300 mV/m. The speed ( of the parallel electric field structures along the background magnetic field (B) is approximately can be hundreds of km/s. These NIAWs can carry significant parallel potential, reaching up to approximately 1000 Volts, which is equal to or higher than the temperature of lobe plasma (in eV), and a substantial fraction of the temperature of the plasma sheet. The observations support that NIAWs with significant electric fields can alter the electron distribution function suggesting that NIAWs may play a crucial role in regulating plasma mixing in the plasma sheet boundary layer.