  Recent advancements in optical, terahertz, and microwave systems have
unveiled non-transverse optical toroidal pulses characterized by skyrmionic
topologies, fractal-like singularities, space-time nonseparability, and
anapole-exciting ability. Despite this, the longitudinally polarized fields of
canonical toroidal pulses notably lag behind their transverse counterparts in
magnitude. Interestingly, although mushroom-cloud-like toroidal vortices with
strong longitudinal fields are common in nature, they remain unexplored in the
realm of electromagnetics. Here, we present strongly longitudinally polarized
toroidal pulses (SLPTPs) which boast a longitudinal component amplitude
exceeding that of the transverse component by over tenfold. This unique
polarization property endows SLPTPs with robust propagation characteristics,
showcasing nondiffracting behavior. The propagation-invariant strongly
longitudinally polarized field holds promise for pioneering light-matter
interactions, far-field superresolution microscopy, and high-capacity wireless
communication utilizing three polarizations.
