The Role Of Convection Transport In Toi Breaking Into Polar Cap Patches

As a significant weather phenomenon in polar space, the polar cap patch formation is one of important issues. It is commonly considered that the high-density sunlit plasma can be transported from dayside, through cusp, over the polar cap, and eventually to the dawnside. Observations suggest that the strong convection flow due to the dayside magnetic reconnection has an important role in TOI (Tongue of ionization) "breaking off", forming polar cap patches. Based on observations to polar GPS/TEC and SuperDARN convection, this paper analyzes the cases of polar cap patches formation process, focusing on two mechanisms of TOI breaking into polar cap patches. The results show that the plasma transportation takes a key role in TOI breaking into polar cap patches, and both the convection pattern and the rapid change of velocity of partial TOI can bring out instability, causing TOI breaking into polar cap patches.