Rippled Electron-Scale Structure of a Dipolarization Front

We use the Magnetospheric Multiscale mission to investigate electron-scale structures at a dipolarization front. The four spacecraft are separated by electron scales and observe large differences in plasma and field parameters within the dipolarization front, indicating strong deviation from typically assumed plane or slightly curved front surface. We attribute this to ripples generated by the lower hybrid drift instability (LHDI) with wave number of kρ_e≃0.4 and maximum wave potential of ∼1 kV ∼k_BT_e. Power law-like spectra of E_⊥ with slope of −3 indicates the turbulent cascade of LHDI. LHDI is observed together with bursty high-frequency parallel electric fields, suggesting coupling of LHDI to higher-frequency electrostatic waves.