| Περίληψη: |
Close-in terrestrial exoplanets around M dwarfs reside in dense, magnetized winds, where non-ideal plasma coupling can strongly affect how electromagnetic energy is redistributed within the dayside interaction region. We present three-dimensional resistive magnetohydrodynamic simulations of the TRAPPIST-1 wind interacting with a dipolar TRAPPIST-1e magnetosphere for three stellar-wind forcing cases and four prescribed magnetic diffusivities, η = (0 , 538.018 , 5.380 18 × 10 8 , 5.380 18 × 10 12) cm2 s−1. Energy transport is diagnosed using maps of the total energy density, the magnitude of the total Poynting flux, and the divergence of the total Poynting flux. We further estimate a radio-power proxy from the volume integral of ∇ ⋅ S t o t a l over the dayside bow-shock and magnetopause layers. Across all cases, increasing prescribed η broadens the coupling layer and shifts the dominant energy-conversion regions from thin, patchy boundary arcs to thicker, more spatially extended structures, with an increasing relative contribution from the magnetopause. The inferred radio-power proxy increases by several orders of magnitude across the explored scan. However, because the estimated numerical magnetic diffusivity in the strongest gradient regions is η n u m ∼ 10 15 – 10 16 cm 2 s − 1 , the present η scan is best interpreted as a controlled sensitivity study rather than as a direct constraint on the physical diffusivity of the TRAPPIST-1e environment. For the adopted planetary fields ( B e q = 0.32 –1.28 G), the maximum cyclotron frequencies are ν c , max ≈ 1.8 –7.2 MHz, below the ground-based window, implying that meaningful radio constraints on TRAPPIST-1e magnetism will require space-based observations below 10 MHz or substantially stronger planetary fields than those assumed here. [ABSTRACT FROM AUTHOR] |