From: Stefan Israelsson Tampe * Not sure that you could rule out a spherical wave. Who knows, but the fact is that the missing radiation is a mystery and I reckon that in a cold fusion event in a solid state, it sure is many orders of magnitude more spherical symmetric than hot fusion, that's sounds like a clue to me.
A paper of interest related to the spherical wave (for spin energy release) involves so-called “skyrmion” bubbles… This sounds a bit like another verbalization of the magnon. Editor's Summary of “Blowing magnetic skyrmion bubbles” by Jiang et al. The formation of soap bubbles from thin films is accompanied by topological transitions. Here we show how a magnetic topological structure, a skyrmion bubble, can be generated in a solid-state system in a similar manner. Using an inhomogeneous in-plane current in a system with broken inversion symmetry, we experimentally “blow” magnetic skyrmion bubbles from a geometrical constriction. The presence of a spatially divergent spin-orbit torque gives rise to instabilities of the magnetic domain structures that are reminiscent of Rayleigh-Plateau instabilities in fluid flows. We determine a phase diagram for skyrmion formation and reveal the efficient manipulation of these dynamically created skyrmions, including depinning and motion. The demonstrated current-driven transformation from stripe domains to magnetic skyrmion bubbles could lead to progress in skyrmion-based spintronics.
