  We consider radial sine-Gordon kinks in two, three and higher dimensions. A
full two dimensional simulation showing that azimuthal perturbations remain
small allows to reduce the problem to the one dimensional radial sine-Gordon
equation. We solve this equation on an interval $[r_0,r_1]$ and absorb all
outgoing radiation. Before collision the kink is well described by a simple law
derived from the conservation of energy. In two dimensions for $r_0 \le 2$, the
collision disintegrates the kink into a fast breather while for $r_0 \ge 4$ we
obtain a kink-breather meta-stable state where breathers are shed at each kink
"return". In three and higher dimensions $d$ a kink-pulson state appears for
small $r_0$. The three states then exist as shown by a study of the $(d,r_0)$
parameter space. On the application side, the kink disintegration opens the way
for new types of terahertz microwave generators.
