[Arm-netbook] http://www.emff.urjc.es/members/arrayas_files/Articles/PhysRep.pdf

[Luke Kenneth Casson Leighton]

hi theo, been talking to the mathematician behind that paper on knots,
he explained that the "null condition" is where the EM field is...
zero, and that the E is perpendicular to M at all points.  it's not
the same thing as the "non-radiating condition" for which you have to
take a fourier transform.

he sent a link to the above paper which he said may have some clues
about non-radiating conditions.

l.