Solar wind proton deceleration at higher altitude above lunar magnetic anomalies

We study interaction between the solar wind (SW) flow and lunar magnetic anomalies. Our recent study showed that incident SW protons are decelerated at low altitude (say, ~25 km) above strong magnetic anomalies, and that SW protons are less or not affected by the magnetic anomalies at higher altitude (~100 km). Here we report that SW protons are strongly decelerated above strong and wide magnetic anomaly region even at the higher altitude under specific SW conditions of high density and strong interplanetary magnetic field (IMF). The SW proton deceleration at higher altitude is accompanied by a strong enhancement in local magnetic field, which suggests that pile-up of the IMF is more effective under the conditions.