Statistical characteristics of plasma flows associated with magnetic dipolarizations in the near‐tail region of r < 12 RE

摘要: [1] The magnetic dipolarization in the tail close to Earth is often associated with plasma flows of some magnitude, and flow direction can be critically related substorm triggering issue. In this work we identified 167 events dipolarizations near-Earth (r ≈ 7–12 RE) using Time History Events Macroscale Interactions during Substorms (THEMIS) observations examined patterns dipolarizations. We first find that ∼50% near-tail region initiate a significant magnitude (>100 km/s). Out such fast events, ∼78% are earthward ∼22% tailward flows, which interpret as rebound flows. The overall occurrence rate (including both flows) noticeably decreases earthward: It drops from ∼47% at r 8–9 RE ∼27% 7–8 RE. This implies seldom penetrate inside RE, consistent previous reports. Incidentally, directions change course entire process whether begins an or flow. Nevertheless, net transport main duration most dipolarizations, even if they dominantly onset.