Structural transitions of finite dust clusters in the presence of wake-mediated interaction and an external magnetic field

We investigate ion-wake-induced structural transitions in finite dust clusters under the combined influence of ion streaming and an external magnetic field using molecular dynamics simulations. In the presence of ion streaming, the interplay between isotropic Yukawa repulsion and anisotropic wake-mediated attraction leads to a reentrant structural transition, in which the cluster evolves from an asymmetric nested-shell configuration to a vertically elongated structure and subsequently recovers its symmetric nested-shell structure as the Mach number increases. This non-monotonic behavior reveals a competition-driven mechanism governing structural organization in strongly coupled finite systems. Such behavior is widely observed in diverse physical systems. We further show that an external magnetic field provides an additional control parameter by modifying ion trajectories and wake strength, leading to dimensional transitions from one-dimensional chain to two-dimensional zigzag and three-dimensional configurations in small clusters. These results reveal a novel mechanism for tunable structure formation in finite strongly coupled systems and establish dusty plasmas as a versatile platform for exploring competition-driven and field-driven self-organization in flowing environments.