"Computers are useless. They can only give you answers."
-- Pablo Picasso (unsourced)

http://en.wikiquote.org/wiki/Picasso

I don't understand. They seem to be setting up two static, plane electric fields at some angle to one another. Surely the resultant field is just another field at a different angle? Say the two fields are E and J , with
E = ( E , 0 , 0 )
J = ( 0 , J , 0 )
Then you've just got the resultant field, E' = E + J , where
E' = ( E , J , 0 )
which is just another static, plane electric field. So, given that two fields are really equivalent to one, if you set up just the resultant field in the first place, would this motor effect still occur?
What am I missing?