Abstract: Plasma jet experiments using planar coaxial electrodes with bias magnetic field, emulating the central object–accretion disk system, are conducted on the BRB at WiPPL. Hydrogen plasma jets (density ∼ 1e+19m−3 at 11 ± 2eV) at high bias voltage (2–3kV) are injected into different H plasma backgrounds (density ∼ 1e+17m−3 at ∼ 5eV). Axial component Bz propagates downstream from the gun, undergoing collimation while elongating. The induced toroidal field Bϕ shows pinching near the column axis, indicative of plasma compression or helicity injection. The current density Jz is strongly collimated, extending up to ∼ 90–100cm from the gun, approximately propagating along collimated Bz lines. Later, both Bz and Jz distributions broaden and weaken, suggesting relaxation or enhanced interaction with the background plasma. This J − B topology is consistent with earlier plasma jet experiments. Bz with average peak amplitude ∼ 240G remain collimated for longer durations when jets are launched into lower density plasma.: lasting ∼ 34μs at 1.0 × 1e+17m−3 compared to ∼ 24μs at 6.2 × 1e+17m−3 (each at 3kV bias). The propagation speed of Bz [90, 76, 46]km/s decreases with increasing background density ∼ [2.1, 3.1, 5.2] × 1e+17m−3, for jets biased at 2kV.