30 kw first stage test
VX -200 Prior to entering Test Chamber
In vacuum chamber
The Variable Specific Impulse Magnetoplasma Rocket (Vasimr) is slated to enter higher power testing. (paid subscription required)
The first stage, a 30kw system, has been successfully tested, and they are now working on a 2nd stage, which will boost the power of the unit to around 200 kw.
The performance benefits, the ISP (basically fuel economy) is more than 10 times that of chemical rockets, would be very significant if this can be made to work.
For example, it could take the time for a transit to Mars from 180-200 days to about 40 days.
Prior posts here.