Plasma precursor solitons driven by finite-sized charged sources: Effects of source alignment, charge, geometry, magnetic fields, and electron–ion temperature ratios

We investigate precursor soliton dynamics driven by finite-sized charged sources in a two-dimensional plasma using two-dimensional three-velocity particle-in-cell simulations with OSIRIS. The study examines how source geometry, charge density, vertical alignment, and external magnetic fields influence soliton formation, structure, and coherence. A single finite line source generates forward-propagating solitons with trailing wakes, while the precursors generated by two vertically aligned sources interact nonlinearly in a non-elastic manner, forming bow- or crescent-shaped fronts. An external magnetic field aligned with the dual-source motion suppresses transverse expansion, eliminating bow- or crescent-shaped fronts and producing narrow, axially elongated, field-aligned solitons with enhanced longitudinal coherence. Unequal source-to-plasma charge ratios induce asymmetric precursor solitons with tilted fronts and uneven downstream structures. Increasing source charge enhances soliton amplitude and propagation distance, whereas low electron-to-ion temperature ratios strengthen Landau damping and reduce coherence. Systematic variations in source shape—including triangular and V-shaped profiles—reveal that the number and orientation of leading slopes govern whether solitons appear one-sided, dual-sided, symmetric, or asymmetric. Scalability tests confirm predictable dependence on the ion-acoustic speed, and simulations under low-Earth-orbit conditions reveal stationary (“pinned”) solitons. These results provide critical insights into how source configuration, plasma parameters, magnetic effects, and non-elastic interactions collectively shape nonlinear wakefields and debris–plasma interactions in laboratory and space plasmas.