Ion Thruster is a thrusting mechanism which is alternative to chemical propulsion used today.
This propulsion uses Lorentz force to accelerate ions.
It can be used for a huge number of purposes. Accelerating ions can provide thrust for a spaceship or satellite.
This technology is better than chemical propulsion in some ways. But, there are some limitations as well.
Once those limitations are overcome, such a rocket can be very well feasible.
You must be thinking that things like StarThis and StarThat are all acts of fiction from the StarWars movie . But, in fact StarTram is not fictitious anymore.
It is actually a patent for a design of a new space launch vehicle. Today, we use jet propulsion to precision for launching space vehicles and satellites. Now, we can start using maglev technique to lauch space vehicles.
A StarTram is just an accelerator for increasing the speed of a payload to orbital velocity speeds.