Sunday, February 8, 2015
Franklin Chang Diaz's VASIMR plasma rocket engine is very similar to the work I did in 1980 (see I.E.E.E. Transactions on Plasma Science, 10, 8, 1982) except that VASIMR uses ICRH ion heating. But it seems to me that ICRH would preferentially increase ion motion perpendicular to the magnetic field when what one wants is ion motion parallel to the B field. I would think that in any case heating the electrons will ultimately accelerate the ions down the plasma potential gradient and out the magnetic nozzle. So preferential ion heating seems unnecessary anyway.