CDI vs. Inductive Ignition Drivers and the "ideal transformer"

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Original poster: "Jolyon Vater Cox by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>

Dear List,
I was musing over merits of electronic drivers for ignition coils used as 
HV transformers in TC service,
trying to figure out whether capacitive discharge ignition (CDI) or 
inductive ignition drivers were better in a circuit where the function of 
the coil is to charge the primary cap of a spark-gap TC.

This led me to wonder if the coupled magnetic field in the ignition coil 
could be used for energy storage
or was this just a "gearbox" which would refer a "transformed" value of the 
capacitor back to the LT side; if the latter were true surely energy could 
not be stored in the coupled inductance  but only in the uncoupled flux 
i.e. the in "leakage inductance" that would appear to be in series with the 
otherwise "ideal" transformer.

Thus, it would appear that less energy can be stored in the magnetic field 
of a transformer with a capacitor connected across the secondary than one 
without. Is this true, and if so what are its implications in the use of 
inductive ignition drivers versus capacitive ignition drivers in TC service?

Finally, is it true that in the hypothetical ideal transformer there can be 
no magnetic field since all the magnetic flux added by the current in 
primary must be subtracted by the magnetic flux from the current in the 
secondary if power in is equal to power out, according to Lenz's Law?

And is this reason why ideal transformers don't exist in reality?