A Tesla coil is not an antenna, although some radiation will take place
from its conductors -- which will probably be damped sinusoidal pulses
similar to a spark transmitter. The radiation will not be all "E", but
will have the same E/H ratio of any radiated signal. i.e. E/H = 377
(ohms) in the far field.

73,

Frank

Just checked http://home.wtal.de/herbs_teslapage/theory.html The Tesla coil
is a spark transmitter without an antenna connected.

Frank