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arXiv · 2602.11823

Intrinsic speed characteristics of a self-propelled camphor disk under repulsive perturbations

Yuki Koyano·Jerzy Górecki·Hiroyuki Kitahata
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Abstract

Camphor is a well-studied material capable of generating self-propelled motion at a water surface, and the resulting dynamics can exhibit a wide range of behaviors. Here, we analyze a one-dimensional model describing a mobile camphor disk perturbed by a second localized camphor source. The interaction between the rotor and the perturbing disk is represented by a distance-dependent potential. The study is motivated by experiments in which a camphor rotor interacts with a fixed camphor disk placed on the water surface. Numerical simulations of the model reproduce the essential features of the experimentally observed position-dependent rotor velocity for all considered forms of the potential. For weak perturbations, we derive analytical solutions valid for arbitrary potential profiles. Both the simulations and the analytical results demonstrate a pronounced asymmetry in the rotor velocity depending on whether the rotor approaches or recedes from the perturbation.

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Yuki Koyano, Jerzy Górecki, Hiroyuki Kitahata. 2026-02-12. Intrinsic speed characteristics of a self-propelled camphor disk under repulsive perturbations. https://doi.org/10.1063/5.0303123

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