Ah, got it. So when we think of “rocket fuel” we’re conflating two things: energy source and propellant. Kerosene and oxidiser gives you both heat and combustion products for the heat to fling out of your nozzle.
Hall effect thrusters decouple energy and propellant. The noble gas is the propellant. It’s stuff you’re throwing. The energy, however, must come from elsewhere, e.g. solar panels or a nuclear reactor.
There is an aerospace term called specific impulse [1]. It measures engine efficiency. Ion thrusters are about as efficient as the turbofans on a modern jetliner. Those, in turn, are about 12x more efficient than the Space Shuttle’s solid-fuel boosters and like 7x better than cryogenic, i.e. hydrogen-oxygen, fuelled engines.
Hall effect thrusters decouple energy and propellant. The noble gas is the propellant. It’s stuff you’re throwing. The energy, however, must come from elsewhere, e.g. solar panels or a nuclear reactor.
There is an aerospace term called specific impulse [1]. It measures engine efficiency. Ion thrusters are about as efficient as the turbofans on a modern jetliner. Those, in turn, are about 12x more efficient than the Space Shuttle’s solid-fuel boosters and like 7x better than cryogenic, i.e. hydrogen-oxygen, fuelled engines.
[1] https://en.m.wikipedia.org/wiki/Specific_impulse