I'm sure most of you on this board know what the VASIMR plasma rocket engine that is being prepared to be tested on the ISS. I read that high-powered radio waves are used to heat the argon gas to the plasma state of matter and then the superconducting magnets eject the superheated gas out of the magnetic nozzle to produce the thrust (~1lb). I also know that the Helicon antenna uses a lot of power (5kw) to produce 1 kilowatts worth of radio waves to heat the argon to the plasma state. My question is that would a UV laser be more efficient in producing the plasma needed to make this work? I know that UV lasers are great at ionizing gases at earths atmospheric pressure. Maybe there is another benefit to using this system. Other than heat, there tends to be little "waste" with lasers.