Helicity Injection by Knotted Antennas into Electron Magnetohydrodynamical Plasmas

A fully three-dimensional computer simulation of an ideal electron magnetohydrodynamical plasma is performed. By introducing various pulsed inductive antenna sources, magnetic helicity ( H  =  ∫ȦB dV) injection is studied. Confirming experimental results, a simple loop provides no net helicity injection. Linked and knotted antennas, however, do inject helicity and preferentially radiate whistler wave packets parallel or antiparallel to the ambient magnetic field. Relative efficiencies of these antennas are reported as well as their unique directional properties.