At the beginning of the derivation it says "ion mass is irrelevant here (no inertia effects)". If it is irrelevant than the derived force does not really correspond to a thrust.
Harry Michel Jullian wrote: >> ...the thrust formula >> I*d/mu where ion mobility mu... > Also, for you Michel, why does the ion mobility equation necessarily > interpret as being ion wind? ... > Dave Because ion [induced] wind yields exactly the above thrust formula if you do the maths, here is an elegant derivation by R.S. Sigmond (if the 16 kB gif image makes it to the list) Michel
