Numerical Investigations of Low‐Latitude Ground Magnetic Fields Due To Cavity Mode Oscillations

33 Pi2 oscillations have been known to be associated with cavity mode oscillations (CMOs) in 34 the inner magnetosphere at low latitudes. CMOs can also be excited by interplanetary shocks 35 on the dayside. We present results from a global linear MHD wave model in spherical 36 coordinates that allows us to analyse these waves at equatorial latitudes. We see that the 37 model reproduces some of the principal CMO harmonics. The standing wave cavity modes 38 are set up due to a dense plasmasphere. The CMOs associated with interplanetary shocks are 39 compared with ground observations from the EMMA array at mid-latitudes. In accordance 40 with observations of Pi2 pulsations, we also see a small phase difference between 41 compressional mode Alfvén waves at midnight at low altitudes and on the noon ground, both 42 at equatorial latitudes. This supports the finding that upon being excited in the nightside inner 43 magnetosphere, these waves travel quickly around to the dayside. We compare our results to