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arXiv · 2602.01333

Ion-Neutral Drift Velocity as a Diagnostic of Dust Growth and Magnetic Field in Star-Forming Environments

Haruka Fukihara·Yusuke Tsukamoto·Hiroyuki Hirashita·Doris Arzoumanian·Yoshiaki Misugi
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Abstract

Recent observations have revealed that the ion-neutral drift velocity in star-forming molecular clouds and dense cores is on the order of 100 m s^-1. Theoretical studies have shown that, in ambipolar diffusion, the process responsible for the differential motion between ions and neutrals, the dust size distribution has a significant impact on the magnetic resistivities. In this study, we perform simulations to investigate how dust growth through accretion and coagulation affects the ion-neutral drift velocity in molecular clouds and cores. We find that, on core scales, both dust growth and a magnetic field strength of 200 microgauss are required to reproduce the observed drift velocity. We suggest that measurements of ion-neutral drift velocity, particularly on core scales, may serve as a new diagnostic to constrain the dust size distribution and magnetic field strength in such environments.

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Haruka Fukihara, Yusuke Tsukamoto, Hiroyuki Hirashita, Doris Arzoumanian, Yoshiaki Misugi. 2026-02-01. Ion-Neutral Drift Velocity as a Diagnostic of Dust Growth and Magnetic Field in Star-Forming Environments. https://doi.org/10.3847/1538-4357/ae3f9c

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