1. Observational evidences of wave excitation and inverse cascade in a distant Earth foreshock region

The foreshock with nascent plasma turbulence is regarded as a fascinating region to understand basic plasma physical processes, e.g., wave-particle interactions as well as wave-wave couplings. Although there have been plenty of intensive studies on this topic, some key clues about the physical processes still lack observations. A relatively comprehensive case study with some new observations is presented in this work based on the WIND spacecraft observations. In this case, upstream energetic protons were drifting at tens of Alfvén speed with respect to the background plasma protons. When looking at the magnetic wave activities, we find the co-existence of high-frequency (0.1−0.5 Hz) large-amplitude right-hand polarized (RHP) waves and low- frequency (0.02−0.1 Hz) small-amplitude left-hand polarized (LHP) waves in the spacecraft (SC) frame.

2. Sea-surface reflection-aided underwater localization with unknown sound speed

The problem of underwater localization has drawn considerable attention in recent years. How- ever, it is quite challenging due to a lack of mea- surements and the unknown sound propagation speed (SPS), even with sensor nodes (SN) having known positions. In practice, sufficient measure- ments might not be available due to the harsh un- derwater environment or the sparse deployment of SNs.