Study of PSR B0943+10 using FAST: the modes, geometry and OPMs Cao, Shunshun We present a study of a well-known mode-switching pulsar J0946+0951 (B0943+10) using FAST. We show its modes' properties under FAST L band, get a reasonable radiation geometry, and discover this pulsar's clear existence of orthogonal polarization modes (OPMs), which shows various properties in different radiation modes and different distributions of the single pulses' circular polarization.