What are the hurdles toward constructing a plasma engine?

by this I mean, a machine that generates hot plasma by heating up the air and then accelerating it electromagnetically to obtain thrust...what are the hurdles. |||The earlier Russian space program, the ESA and NASA have all used ion engines on spacecraft. The European space agency has recently built a proof of concept model for an improved version with greater thrust.





Basically a stream of ionised gas (plasma) that can be accelerated by a magnetic or electromagnetic field. These things need to be in a vacuum more or less, in other words space. The advantages of ion engines is a high velocity thrust, for high speed, and operation for long periods and good efficiency. The thrust is small, but the speed builds over time. Only a small amount of the raw material used to make the plasma is used. Often electromagnetic energy (microwave) is used to heat the gas into a plasma.





No doubt there will be improvements over time. Perhaps it is possibleto do it in the atmosphere one day as you suggest, but the current generation would not offer much. In the atmosphere we are after huge thrust and not too bothered about speed.. Incidentally the exhaust of chemical rockets is a plasma.





If you have a lot of power like a nuclear reactor, who needs a plasma in the atmosphere. You can just heat the air, steam etc. There have been nuclear powered aircraft and missiles programs, but the shielding remained an unsolved issue. The link below shows that "Two General Electric turbofan engines were successfully powered to nearly full thrust using two shielded reactors." |||The energy in even getting it to be a plasma would be quite interesting. perhaps if you had a microwave generator in some area away from metal parts that could create the ionized gas (Plasma) out of air and a flame. Maybe a hurdle would be the safety of such a device. If you have a nuclear reactor generating this heat, that would not be fun having cancer in the next few weeks. |||The purpose of this device is what? A massive heater? To push trains?





Anyway, it sounds inefficient compared to conventional electric motors.