A COMPARATIVE ANALYSIS OF PLASMA INJECTION BETWEEN MERCURY AND EARTH
Seminars
Plasma circulation at Mercury and Earth is predominantly driven by the Dungey cycle, a picture in which the large-scale background plasma transport in the nightside plasma sheet. However, strong magnetotail dynamics can greatly deviate from this steady-state pattern when the cross-tail current is disrupted through reconnection. This drives sudden, burst-like earthward plasma flows that episodically inject plasma into the inner magnetosphere, providing seed particles for radiation belts, populating the ring current, and creating particle velocity-space anisotropies that drive plasma waves that are responsible for further acceleration in the inner magnetosphere. We present both case studies and statistical surveys on energetic plasmas at Mercury and Earth, placing an particular emphasis on injection-related events. We characterise the typical energies, typical life-times, spatial dependence, and correlation with the magnetic field (as well as flow speed, cross-tail electric field and geomagnetic activity on Earth) for the observed injected plasmas in different planetary magnetospheres. This work serves for constructing a comparative picture of plasma “injections” in different planetary systems, in aid of understanding whether the distinctively different field and plasma environments can drive the same plasma transport and acceleration process, or if these injections-like phenomena are driven by fundamentally different physics.
Additional information: Mr. QIN Tianshu, qint2023@connect.hku.hk