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Bingkun Yu

Publications and source records attributed to Bingkun Yu.

2 recordsLinked to original sources

Probing Triton's Space Environment and Internal Structure: An Integrated Detection-and-Interpretation Framework

Triton, Neptune's largest moon, is a prime ocean-world target. Constraining ocean thickness, composition, and conductivity is essential for habitability assessment, but magnetic induction alone cannot resolve the thickness-conductivity degeneracy, and magnetic perturbations from Triton's space currents can obscure the internal induction signal. We present an integrated detection-and-interpretation concept linking four physically consistent calculations. Using `PlanetProfile', we construct a common radial interior structure (temperature, density, conductivity, seismic-wave speed). We then use `MoonMag' to compute the degree-one magnetic-induction response from that conductivity profile at the synodic, rotational, and orbital periods. We perform a multi-fluid `SWMF' simulation with the induced dipole as the inner-boundary condition and develop a Coulomb-gauge Poisson reconstruction to isolate space-current magnetic fields. Finally, we develop the `TritonSeis' workflow, three-dimensional seismic forward modeling plus hierarchical travel-time inversion, to constrain the ice-ocean and ocean-rock interface depths. We find that induction is substantially more sensitive to ocean conductivity than to layer thickness, and that space-current fields are comparable in amplitude to the internal induction signal. A five-station synthetic recovery test resolves both interfaces to first order, with errors of +8.4% for the ice shell and -12.5% for the ocean. Under a conservative noise assumption, the minimum detectable magnitudes are approximately 3.8-4.6 at epicentral distances of 100-1000 km. The Poisson reconstruction and end-to-end seismic recovery are, to our knowledge, the first such quantitative demonstrations for Triton. Coordinated magnetic, plasma, and seismic measurements are complementary and can break the conductivity-thickness degeneracy, providing a framework for future Triton exploration.

astro-ph.EP

Interplanetary Coronal Mass Ejections and Stream Interaction Regions observed by Tianwen-1 and Maven at Mars

Tianwen-1 spacecraft (Wan et al. 2020) is China's first Mars exploration mission. The Mars Orbiter Magnetometer (MOMAG) is a scientific instrument aboard the Tianwen-1 mission that is designed to study magnetic fields at Mars, including the solar wind to the magnetosheath and the ionosphere. Using the first Tianwen-1/MOMAG data that is publicly available, we present interplanetary coronal mass ejection (ICME) and stream interaction region (SIR) catalogues based on in-situ observations at Mars between November 16, 2021, and December 31, 2021. We compared the magnetic field intensity and vector magnetic field measurements from Tianwen-1/MOMAG and Mars Atmospheric Volatile EvolutioN (MAVEN)/MAG during the ICME and SIR interval and found a generally good consistency between them. Due to MAVEN's orbital adjustment since 2019, the Tianwen-1/MOMAG instrument is currently the almost unique interplanetary magnetic field monitor at Mars. The observations indicate that the MOMAG instrument on Tianwen-1 is performing well and can provide accurate measurements of the vector magnetic field in the near-Mars solar wind space. The multi-point observations combining MOMAG, MINPA, and MEPA on board Tianwen-1 with MAG, SWIA, and STATIC on board MAVEN will open a window to systematically study the characteristic of ICMEs and SIRs at Mars, and their influences on the Martian atmosphere and ionosphere.

physics.space-ph