Conducting-Coil Assembly for Producing Three-Dimensional Magnetic Null Points

Three-dimensional magnetic null points (3D nulls) are sites of dynamic activity and particle acceleration in astrophysical environments. Future laboratory infrastructures to validate theoretical models of observed plasma dynamics about 3D nulls will benefit from an experimental infrastructure that closely reproduces these analytical potential magnetic fields. As such, a conducting-coil assembly is presented that closely matches the theoretical form of a 3D null within an interior volume. Exact magnetic field solutions are attained for a spherical aggregation of circular current-carrying coils with finite cross sections that create a central magnetic null point of vanishing magnetic energy density. This configuration is shown to replicate the fan-plane--spine-axis topology of 3D nulls to a high order within the central volume close to the null. Finally, numerical analyses demonstrate that the investigated architecture is scalable over wide size and energy ranges. Applications of the presented conducting-coil assembly include sophisticated next-generation plasma experiments and particle accelerators.