JIMO attitude control systems

Hi,

Just read an article on SpaceFlightNow.com about a new ion engine
being developped and tested with substantial improvements over older
designs, such as the one used in Deep Space 1 [1].

I was wondering how they're considering the attitude control
systems... One of the limitations for Galileo was the fuel, same goes
for Cassini... I was reading the other day about the attitude control
on Hubble, which works with a combination of momentum wheels and
magnetic torquers for CMG desaturation manoeuvers, since there's a
risk for contaminating the optics with normal thrusters.

Would Jupiter's or Jovian moon's magnetic fields be powerful enough to
enable the use of magnetic torquers?

Of course, one would bring along chemical-based thrusters for
emergencies or manoeuvers where CMGs would just not cut it...